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For cell proliferation over time, 3 and 6 kN showed no differences, but 9 kN showed a significant difference between day 4 and day 8 (^p=0.031). SEM and histological analysis showed a network of cuboidal cells on the allograft surface.
To investigate osteoclastogenesis in vitro Peripheral Blood Mononuclear Cells (PBMC) were isolated from healthy volunteers and cultured over a two-week period under stimulation by cytokines (RANKL, M-CSF, VEGF, PlGF, a specific ligand for VEGFR 1 and VEGF-D, a specific ligand for VEGFR 2). RAW 264.7 cells (a mouse monocyte/macrophage cell line able to differentiate into osteoclast-like cells) were cultured for seven days under stimulation by cytokines (RANKL, VEGF and M-CSF). Osteoclasts were identified by staining for Tartrate Resistant Acid Phophatase (TRAP) and numbers of multinucleated cells counted per treatment. Culture on ivory slices was performed to measure resorption activity of the osteoclasts.
The PBMCs stimulated by VEGF and RANKL together differentiated into multinucleated TRAP positive cells in similar numbers (22±4.7) per field of view to the M-CSF and RANKL (27.3±7.2). Resorption of ivory was identified in these cultures. Stimulation with PlGF and RANKL resulted in increased osteoclastogenesis but VEGF-D with RANKL had little effect. Similar results were seen in triplicate experiments RAW 264.7 cells also differentiated into osteoclast-like cells after stimulation with VEGF and RANKL similar to M-CSF and RANKL.
Image analysis results demonstrated an average bone attachment of 30.94% to the implant surface (fig 2). Greatest bone attachment occurred at the end of the pins (78.99%) contributing 22% of overall attachment to the implant. Least attachment occurred beneath the prosthetic cup (13.82%) and in the medial aspect adjacent to the central pin. Greater total bone area was measured in control hips and no significant correlation between bone attachment to the ‘pegs’ and bone area beneath the prosthetic cup was identified.
The aim of this study was to (I) determine the intra-operative temperature of the femoral cancellous bed prior to insertion of prosthesis, (II) to investigate whether the magnitude of the temperature gradient effects interface porosity (III) to develop clinically relevant recommendations.
The cement mantle was sectioned transversely, then longitudinally to expose the cement-prosthesis interface. This was stained with acrylic dye to facilitate image analysis. Three mantles for each temperature were produced.
In order to determine factors that stimulate activin A production, chondrocytes were isolated from human cartilage and stimulated with various cytokines. RT-PCR methods were used to measure activin mRNA production and the culture medium was assayed for activin protein. Cartilage explants were also stimulated and activin protein levels were measured.
Using a newly developed fracture model of the proximal tibia of the rat, the effect of simvastatin on osteoporotic and non-osteoporotic fracture healing was investigated. The fracture model was used as it provided a useful model of metaphyseal fracture healing which is particularly relevant to osteoporotic fracture.
X-rays of the healing fractures were taken. Both the intact and fractures tibiae were then taken for mechanical testing by four point bending.
Although end-to-side neurorrhaphy did support nerve regeneration with sometimes good return of muscle function, the use of this technique as a clinical tool at this time cannot be recommended.
We measured 1: the area occupied by a cell and 2: the number of focal adhesions per cell. The largest values of osteoblastic cell area were seen with the smoother vitallium surface. In contrast, samples with more numerous and larger surface features resulted in the osteoblasts covering a smaller area and being confined by topographical elements (Ti2> TM2F> Ti6Al4V). In terms of adhesion, there were generally more focal adhesions per cell on rougher surfaces (Ti6Al4V> TM2F> Vitallium> Ti2).
MLO-Y4 cells were treated with physiological doses (10−8)M of either 17-beta E2 or the oestrogen receptor inactive stereoisomer 17-alpha E2 with or without the specific oestrogen receptor antagonist ICI 182,780 prior to the addition of 0.4milliM 30% (v/v) H2O2. Cellular apoptosis was determined using morphological and biochemical criteria.
The cellular production of reactive oxygen species was determined using the free radical indicator 2′7′- dichlorodihydrofluorescein diacetate. H2O2 induced increases in the number of ROS positive cells (34.6 ± 9.07 SD vs control 0.22 ± 0.39 SD). In contrast pre-treatment with both 17-beta E2 and 17-alpha E2 reduced the number of ROS positive cells associated with H2O2 treatment (Fig 1).
Our aim was to assess femoral offset and leg length following hip resurfacing and hybrid THR (uncemented acetabulum) performed by the same surgeon.
All films were analysed by the same investigator using the technique described by Jolles et al (J Arthroplasty 2002). A horizontal line was drawn between the base of the teardrop on both sides, and perpendicular lines drawn from the back of the teardrops. The anatomical femoral axis was drawn and femoral offset measured from this. The centre of rotation of the femoral head was determined by templating and the acetabular offset obtained.
Distance from tip of the greater trochanter to the centre of the femoral head in the axis of the femur was determined on pre and post-op films, as this shows little variation with rotation of the femur. Leg length was measured from the horizontal line to the tip of the greater trochanter together with the angle between the femoral axis and the horizontal to correct for abduction of the hip.
The aim of this study was to deduce the effect of Hip flexion on the knee’s full extension angle (popliteal angle) in a control group of subjects with normal knees.
In contrast, the release of the inflammatory cytokine TNF-α and the multifunctional growth factor TGF-β-2 occurred at lower doses (0.0005 to 5 μm3/cell for TNF-α and 0.5 to 50 μm3/cell for TGF-β-2). No release of IL-6 was detected at any dose. Only growth factor FGF-23 was increased in similar pattern to the DNA damage.
Contact patterns have been examined ex vivo
The objective of this study was to determine the feasibility of using a surface laser scanner to determine cartilage thickness and, therefore, likely contact area and to correlate changes in thickness to changes in sphericity of the articular surface.
The cloud point data for the cartilage and bony surfaces were exported into modelling software (McNeal and Assoc., Seattle, WA) and the surface area of the head divided into ten equal sections. For each slice of both the cartilage and bony surface, the radius of curvature was calculated using a least square fit optimisation technique
normal, grade IV chondral damage, osteochondral defects or endstage osteoarthritis (OA) of the knee, categorised by the cartilage appearance at arthroscopy.
Levels of matrix metalloproteinases (MMPs) 2 and 3 and the inhibitor, TIMP 1, were measured in the fluids via ELISA assays. Urea levels were measured in blood and synovial fluids and enzymes and their inhibitors were normalized according to the ratio of serum:SF urea, to account for the dilution factor of the SF (Kraus et al 2001). Western blotting was used to identify the presence of aggrecan components (chondroitin-4-sulphate: 2B6 antibody; C-6-S: 3B3 and C-0-S: 1B5; keratan sulphate: BKS-1; the G1 domain: 7D1; interglobular domain: 6B4) and also enzyme degradation products of MMPs (BC14) and aggrecanases (BC3; BC-13).
Dentin matrix protein (DMP-1), a phosphoprotein highly linked to dentin formation, has recently been reported to have an important role in skeletal development. Previously we reported that adult mice lacking the gene for DMP-1 exhibit the characteristics of chondrodysplasia, osteoarthritis, and showed severe defects in mineralization. DMP-1 knock-out (KO) mice display a profound defect in mineralization, and this is not due to a systemic defect in calcium/phosphate metabolism because serum levels of calcium and phosphate are similar to those in the wild-type mice. Although KO neonates and newborns appear normal, upon closer examination, these animals exhibit skeletal abnormalities, which include delayed secondary ossification and impaired bone remodelling. Heterozygous DMP-1 (H) mice however, show no apparent differences to the wild-type mice. In this study, biomechanical assessment tests of bones from DMP-1 KO mice were performed. Fifteen heterozygous, H, (DMP-1 +/−) and 15 KO, (DMP-1 −/−) male mice were produced and used in this study. At 1, 3 and 7.5 months of age, the mice were sacrificed and 4–5 ulnae from each animal group were harvested and stored in 70% ethanol solution. Volumetric density (BMD) measurements of the intact ulnae were performed using peripheral quantitative computed tomography (XCT960M; Stratec, Pforzheim, Germany) and Norland Stratec software version 5.10. One millimetre thick slices were scanned at a distance of 1 mm under the articular cartilage surface of the elbow as identified by the scout view of the CT scan. BMD of the corticalis and subcortical bone were recorded. Cross-sectional area measurements were also made at the mid-diaphysis of the ulnae. Biomechanical tests were performed in 3-point bending, with supports 3.5 mm apart at a rate of 3 mm/min (Lloyd Instruments Ltd, UK). The ultimate load, yield load and stiffness were determined from the load-displacement curves. All data were analysed using Mann-Whitney U tests (SPSS, Version 9, Chicago, Illinois). Differences were considered significant at p < 0.05. Density studies revealed that H mice had higher BMD than KO mice at all ages (p < 0.001). In the H and KO mice, the cortical BMD peaked at 3 and 7.5 months, respectively. At 1 month, the mean cross-sectional areas of the ulnae were larger in H mice compared to KO mice (0.50 mm2 Vs 0.33 mm2). However at 7.5 months of age, the reverse was observed (H = 0.75 mm2 and KO = 0.98 mm2). Biomechanically, stiffness increased with age at a higher rate in H mice than KO mice. Significant differences were observed at 3 months (p< 0.01) and 7.5 months (p< 0.05) between the two animal groups. There were no significant differences between stiffness values at 1 month. This study has demonstrated that DMP-1 deficiency leads to:
severely compromised bone mineralization; poor biomechanical properties of the long bone; and delayed bone development and remodelling. In conjugation with previous findings that DMP-1 plays important roles in the early developmental stage of bone through its effects on osteogenic gene expression of Cbfa1, Col I, and Col II and regulating vascular invasion, the current study may suggest another important role for DMP-1 as a regulator for skeletal mechanostasis.
The potential importance of bone morphogenic proteins (BMPs) to improve fracture healing is of great interest to orthopaedic surgeons. Although the complex mechanisms leading from the presence of local BMP (either endogenous or exogenous) to form bone is increasingly understood, however most appropriate time to administer exogenous BMP has yet to be elucidated. The purpose of this study was to investigate when BMP may be administered to a fracture arena in order to best improve fracture healing. Forty mice were randomised into 4 groups; (group I) control, treated at day 0 with placebo; (groups II, III and IV) treated with BMP at days 0, 4 and 8, respectively. All animals underwent a previously validated surgical procedure involving the creation of an open femoral fracture which is stabilised using a 4 pin external fixator. Thirty microlitres of bovine serum albumin (BSA) alone was used in group I, and the other groups (II, III and IV) were treated with a combination of the BSA and 2.5 microgrames of rhBMP-2. The BSA and rhBMP were injected through a lateral approach immediately after operation, or at 4, or 8 days postoperatively. At days 0, 8, 16 and 22, sequential radiographs were taken using a digital x-ray machine and at day 22 all animals were sacrificed. Both femora were harvested and assessed biomechanically in 3-point bending prior to fixation for histological evaluation. All data were analysed using Mann-Whitney U tests (SPSS, Version 9, Chicago, Illinois) and differences were considered significant at p < 0.05. X-ray analysis indicated that healing of fractures treated with BMP at day 0(group II) or day 4(group III) was significantly greater than that at both days 16 and 22 (p < 0.05) than those animals in placebo (group I) and BMP day 8(group V) treatment groups. Although the administration of BMP at day 4 seemed to cause more bone formation than treatment at day 0, no significant difference were observed. There were no differences between group IV and group I. Biomechanically, group III exhibited ultimate load values closest to the contralateral unoperated femora followed by group II, then IV and finally the control group I. Significant differences (p < 0.05) were observed between the control animals (group I) and both groups II and III. Qualitative histology suggested that at 22 days after surgery, only groups II and III had healed with woven bone. Group I and group IV had considerable amounts of fibrous tissue and cartilage at the fracture gap. This study suggests that a single percutaneous injection of BMP has a positive effect on fracture healing in this model, when prescribed between the time of injury (day 0) and 4 days. Data suggests that the most effective timing of delivery of BMP may not be at the time of surgery but actually in the early healing phase. The day 4 time point in the mouse model is likely to equate to that of 7–10 days in larger animals or humans. This suggests that current human treatment practices may require further investigation in order to elucidate the most appropriate time of delivery for these important proteins. This work may negate the current requirements for carrier products and large doses of these expensive drugs.
During bone development and repair, angiogenesis, osteogenesis and bone remodeling (resorption) are closely associated processes with some common mediators involved. BMPs, VEGF and other cytokines are released from bone during bone resorption. Recent study showed that VEGF caused a dose- and time-dependent increase in bone resorption in vitro and in vivo, and BMP-2 markedly enhanced osteoclast differentiation induced by sRANKL and M-CSF in mouse osteoclast culture system. The aim of this study was to further examine the effects of VEGF and BMP-2 on osteoclastogenesis using in vitro human osteoclast culture system. Mononuclear cells were isolated by Lympo-Prep density gradient centrifugation from bone marrow washouts in bone samples from patients undergone total hip replacement. Mononuclear cells were plated at a density of 1 x 106/cm2 in a T-75 flask with aMEM and 15% FCS. The first medium change was made at day 7, when the floating cells were collected from the withdrawn media by centrifugation, and plated in a separate flask. The non-adherent cells in the 2nd flask were harvested again 24 hours later in a similar fashion. The non-adherent cells were then cultured in 24-well plates or calcium phosphate (Ca-P) coated plates, with osteoclast-inducing media (OC media) containing sRANKL 30 ng/ml and M-CSF 30 ng/ml, media were changed every 4 days. After 4 days culture in OC media, rhBMP-2 (3, 30, 300 ng/ml) and VEGF (25 ng/ml) were added respectively or in combination to the cell culture, and the culture was kept for total 16 days. The number of TRAP positive multinuclear cells in each well and the resorptive pit areas on the Ca-P coated plates were calculated and compared. Osteoclastic cell phenotype was defined by expressing tartrate resistant acid phosphatase (TRAP), vitronectin receptor (VNR) and resorptive pit assay. By day 12–14, osteoclastic cells were found in all the experimental groups, they were positive for TRAP and VNR. The number of TRAP+ multinuclear cells were significantly reduced (p< 0.05, t-test) when rhBMP-2 (30 and 300 ng/ml) were present, and this was further reduced (p< 0.01) when rhVEGF was added together with rhBMP-2, comparing to the culture with OC media alone. Extensive lacunar resorption pits in the Ca-P coated plates were found in the culture treated with OC media and OC media with rhVEGF (25 ng/ml). The resorption pit areas were, however, significantly reduced when rhBMP-2 was added at 30 and 300 ng/ml with or without rhVEGF (25 ng/ml, p< 0.05, t-test). The presence of low concentration of rhBMP-2 (3 ng/ml) with VEGF had no effect on osteoclast number or the areas of resorption pit formation. In contrary to previous findings in the mouse osteoclast culture system, the present study had shown that the presence of rhBMP-2 at 30 and 300 ng/ml had strongly inhibited osteoclast differentiation and bone resorptive capability in the human osteoclast culture system, and the inhibition was further enhanced by the presence of rhVEGF. This study implies that VEGF and BMP-2 may be important, yet to be defined regulators, for osteoclastogenesis.
Fine-wire fixator systems have been used successfully for the treatment of fractures, malunions and for limb lengthening for many years. There has been much research investigating the biomechanical properties of these systems but this has been almost entirely centred on the mechanical properties of the fixator as a whole. Our knowledge of the interactions occurring at the interface between wire and bone remains sparse. To this end we devised an experimental model to analyse the distribution of pressure in cancellous bone surrounding a tensioned wire under loading conditions. The Sawbones cancellous bone material (type 1522-11) was cut into 65x30x40 mm blocks. A 2 mm olive wire was inserted into each block, parallel to the surface and along the 65 mm dimension. The distance from the wire to the surface was variable, from 0.5mm to 5mm in a 0.5mm increment. The wire was mounted on a 150 mm ring and tensioned to 1200 N against a load cell. The ring was rigidly mounted on a material testing machine and a second bone block was incorporated into the testing machine crosshead with a universal joint. Three grades of pressure-sensitive films (Low, Superlow and Ultralow) were sandwiched in turn between the testing block and cross head. The force applied was 175 N for 5 s. The developed film was scanned into a computer and a Matlab program was developed to analyse the pressure image. The results show three phases of pressure distribution. Very close to the wire there is a polar distribution of pressure that is, the pressure is concentrated towards the entry and exit points of the wire. At a depth of 1.5mm away from the wire the pressure becomes evenly distributed along the path of the wire in a beam-loading manner. At a distance of greater than 4mm from the wire there is even distribution of pressure throughout the bone. The peak pressures (6–8 MPa) were found closest to the wire. Most of the pressure measured was less than 1 MPa, which is less than the yield strength of cancellous bone (2–7 MPa, Li and Aspden, 1997). In contrast a similar analysis using threaded half pins under the same conditions showed far higher peak pressures (20 MPa), which were present deeper in the bone specimen. The pressure was concentrated toward the pin entry site and was not well distributed throughout the pin-bone interface. These results allow us to explain why ring fixators are superior to half pin fixators when used in metaphyseal bone.
Percutaneous vertebroplasty (PVP) is an emerging interventional technique for treatment of vertebral compression fractures. Bone cement is introduced to mechanically augment fracture and pain relief is almost immediate. Recent clinical and biomechanical studies have outlined the phenomenon of fractures occurring in adjacent vertebrae following PVP [
Most biomechanical studies adopt a single vertebral body as a model for PVP analysis. With this approach it is not possible to determine the effect of load distribution on adjacent structures. Where multi-segment vertebrae have been used there is little documentation of the fracture characteristics produced or their repeatability. The purpose of this study was to develop a 3-vertebra model for the biomechanical analysis of PVP. The particular focus was on developing a robust technique for generating repeatable level of fracture severity from specimen to specimen.
An alignment device was developed to fit into standard materials testing machine, which allowed constant axial compression without causing lateral bending or flexion-extension of the specimen’s ends. Porcine 3-segment specimens (T8-L2) were mechanically compressed to failure at a rate of 5mm/min applied vertically at a distance of 35% to the anterior edge of the specimen’s anterior-posterior length. During the test load-displacement data was displayed in real time on a PC. In order to generate uniform fractures, a protocol was devised in which the specimens were compressed for a further 6mm after initial yield point. After the initial fracture the segments were augmented with 3ml of PMMA cement injected through each pedicle and then recompressed. The fracture characteristics generated under these conditions were analysed using quantitative microcomputer tomogragy (μCT).
μCT images showed that fractures were generated in the central vertebra, with some propagation towards adjacent vertebra. The results support the use of a 3-segment specimen as a better representation for PVP analysis. The method will enables the load shift and fracture progression on either side of the augmented vertebra to be observed, thereby providing a more complete picture of load-bearing kinetics. Secondly, the middle, augmented motion segment remains unconstrained by platens and cement impressions; hence its anatomical boundary conditions are less compromised. Although longer segments have been shown to be more anatomically appropriate, it is difficult to apply physiologic levels of load without causing the specimen to buckle. We were able to minimise buckling effect by incorporating an alignment device to position the specimen without constraint. Given the preceding observations, the concepts of 3-segment specimen in PVP biomechanical tests provides a suitable compromise in choosing an appropriate clinical setting for in-vitro testing of biological spine specimens.
The purpose of this study was to determine and compare the effects of radiofrequency ablation and mechanical shaving on tendon using histological and ultrastructural techniques. A single cut using a scalpel blade was used to create a standardised reproducible lesion in 12 freshly harvested ovine infraspinatus tendons. Each lesion was then subjected to either bipolar radiofrequency ablation or mechanical shaving. Specimens were either fixed in formalin and processed for light microscopy or fixed in glutaraldehyde and processed for transmission electron microscopy. Samples of normal and untreated cut tendon were analysed as suitable controls. The radiofrequency treated samples showed an area of coagulative necrosis with an average diameter of 2mm around the lesion. Conversely, the shaved samples showed viable cells up to the edges of the lesion. These findings were supported by ultrastructural appearances, which showed preservation of tendon architecture in shaved samples and widespread denaturation of the tendon matrix with loss of fibrillar structure in the radiofrequency treated samples. Radio-frequency electrical energy and mechanical shaving are often used for resection of soft tissues during arthroscopic reconstructive procedures. The effects of these techniques on tendon are not yet clearly understood. The results of this study indicate that thermal resection of tendon causes an immediate additional 2mm area of tissue necrosis which is not present after mechanical shaving. These findings may have implications for the success of arthroscopic debridement and tendon repair procedures.
Although the function of proteoglycans within the tendon extracellular matrix are not fully understood, changes in their turnover have been associated with tendinopathies. In contrast to cartilage, aggrecanases are constitutively expressed and active in tendon, indicative of a high rate of aggrecan turnover. Clinical trials investigating the use of active site MMP inhibitors have been confounded by side-effects which involve tendonitis and “musculoskeletal syndrome”. Such side effects may relate to non-specific inhibition of tendon aggrecanases required to maintain normal metabolic homeostasis. The purpose of this study, therefore, was to compare the rate turnover of tendon and cartilage proteoglycans derived from the same joint and to determine the effect of MMP inhibitors (actinonin and marimastat) on aggrecan catabolism. Deep digital flexor tendon explants from compressed and tensional regions were dissected from young and mature bovine. Explants were precultured and then cultured for a further 4 days with or without marimastat (0–2 M) or actinonin (0–200 M). Proteoglycan and lactate quantification, Western blot analysis of degradation products and RT-PCR analyses were performed on these samples. In a separate experiment for measurement of proteoglycan turnover, explants were set up as described above then pulse chase labelled with [35S] sulphate. The rate of turnover of 35S-labelled proteoglycans from the matrix of tendon (and articular cartilage obtained from the same animal) was subsequently calculated from the amount of 35S-labelled macromolecules appearing in the medium each day and that remaining in the matrix of explants at the termination of culture. Proteoglycan turnover (presumably predominantly aggrecan) was markedly higher in tendon versus cartilage. This difference was apparent in tendons from all regions and ages. Both marimastat and actinonin inhibited aggrecanase-mediated proteoglycan catabolism in both tendon and cartilage explants. As expected mRNA expression for the aggrecanases, MMPs and TIMPs was unaffected by addition of these inhibitors to the culture medium. Aggrecan turnover in tendon is higher than that of articular cartilage, which may be attributed to distinct physiological properties of this proteoglycan in tendon. Importantly, immunohistochemical staining for aggrecan in tendon indicates its presence in between collagen fibres and fibril bundles and thus aggrecan aggregates may dissipate resultant compressive loads by resisting the flow of water in these locations. In addition, aggrecan may facilitate the sliding of fibrils during the small amount of elongation of the tendon whilst under tension. Thus, the half-life of tendon aggrecan is significantly reduced because it constantly participates in repeated resistance to compression. Our data also demonstrates that both marimastat and actinonin can inhibit aggrecanase-mediated proteoglycan catabolism in tendon cultures. This suggests that the occurrence of “musculoskeletal syndrome” in clinical trial patients may be due to the fact that these inhibitors affect the activity of aggrecanases in tendon, thus preventing them from playing their normal role in tendon aggrecan turnover and consequently perturbing normal physiological function.
The energy-storing human Achilles tendon and equine superficial digital flexor tendon (SDFT) show no adaptation to exercise unlike muscle and bone, and are prone to injury. Injury involves microdamage accumulation until there is sufficient weakening for rupture to occur during normal athletic activity. Anatomically opposing positional tendons, such as the common digital extensor tendon (CDET) in the horse rarely suffer exercise–induced injury. Tenocytes maintain the extra-cellular matrix, but in energy-storing tendons they appear unable to adequately repair microdamage as it occurs. Tenocytes have been classified subjectively into 3 subtypes on the basis of histological nuclear morphology. Long, thin type 1 cells are thought to be less synthetically active than cigar-shaped type 2 cells, but their exact morphology and relative proportions in different tendon sites and ages has not been clearly defined. We hypothesised that tenocytes are separable into morphologically distinct subtypes, reflecting differences in age and functional requirements within and between specific tendons. Samples were taken from tensional and compressed regions of the SDFT and CDET of 5 neonates, 5 foals (1–6 m), 5 young adults (2–6 y) and 5 old horses (18–33 y) Cell nuclei were counted and measured in digital images from histological sections by computerised image analysis. Total tenocyte densities and proportions of the 3 subtypes were calculated for each age group, as were nuclear length:width ratios. Length:width ratio distributions for all horses were evaluated using a normality test followed by a paired t-test. There was a significantly higher total cellularity in the SDFT than the CDET, with a higher proportion of type 1 tenocytes in the CDET. With age, total cellularity decreased in all tendon sites and an increase in the proportion of type 1 tenocytes was observed in tensional regions. Foal and neonatal tendons contained significantly higher proportions of type 2 tenocytes than older tendons. The morphology of the two main subtypes in all age groups was significantly different; type 1 tenocytes had a higher nuclear length:width ratio (mean ± SD = 9.6 ± 2.5) than type 2 (mean ± SD =4.7 ±1.1) (p< 0.001). We were able to objectively separate tenocytes into 3 distinct subtypes based on nuclear length:width ratio measurements. There were significant differences in proportions of subtypes with tendon site and age. The positional tendon had significantly lower cellularity and a higher proportion of type 1 tenocytes; these cells may be less functionally active but sufficient to maintain the matrix in a tendon which is not subjected to high levels of strain. The SDFT continues to grow up to 2 years of age and is subjected to high strains, explaining the need for relatively higher proportions of type 2 cells. There is however an age-related increase in type 1 cells in both tendons which may explain an inability of the adult energy-storing tendon to adapt to exercise and to repair microdamage. Understanding the stimulus for age-related changes in tenocyte subtype proportions in tendons with different functions may help us understand the pathogenesis of exercise-induced tendon injury and to develop more appropriate training regimens.
Degenerative joint disease (DJD) involves the proteolysis of many extracellular matrix molecules (ECM) present in articular cartilage and other joint tissues such as tendon, meniscus and ligaments. Recent research has identified key enzymes involved in the catabolism of ECM. Two classes of enzyme the Matrix Metalloproteinases (MMP’s) MMP-2, MMP-3, MMP-13 and the ADAMTS family (a disintegrin and metalloproteinase with thrombospondin motifs) of proteinases most notably, ADAMTS-1, -4 and −5, have been shown to be involved in the catabolism of ECM (such as type II collagen and cartilage aggrecan). The presence of several MMPs in the synovial fluid has been reported; however, little data has yet been gathered on the presence of ADAMTS-1, -4 or −5 (the aggrecanases) in synovial fluids. In this study we have used a recombinant artificial substrate and specific neoepitope antibodies that recognise either MMP- generated or aggrecanase -generated degradation products to measure the relative activity of these two enzyme families in the synovial fluid from human patients.
Osteoblast growth and differentiation are central to the formation and maintenance of healthy bone tissue. The search for novel mechanisms resulting in osteoblast maturation are highly desirable on several fronts. Firstly they provide potentially important information on the normal development of bone, in addition they may offer alternative therapies for bone diseases like osteoporosis and finally they may facilitate ex-vivo manipulation of cells for the subsequent improvement of oseointegration in transplantation/tissue engineering regimens. Recently we have been addressing how calcitriol, an active metabolite of vitamin D3, integrates with the signalling of epidermal growth factor (EGF) following reports that calcitriol can influence EGF receptor trafficking, expression and ligand binding. We have also extended our studies to investigating how other growth factors known to signal via receptor tyrosine kinases (RTKs) interact with calcitriol in controlling osteoblast growth and differentiation. The co-treatment of human pre-osteoblasts (MG63) with EGF and calcitriol resulted in the synergistic induction of their differentiation as supported by demonstrable increases in alkaline phosphatase activity and osteocalcin. The intracellular components responsible for eliciting the maturation response included protein kinase C and MEK 1/2 since the addition of calphostin C or UO126, respectively, blocked the differentiation response. Other ligands known to signal via RTKs, namely IGF1, VEGF and FGF1 could not induce differentiation in the presence of calcitriol. These findings support the specific integration of calcitriol/EGF signalling in osteoblast maturation. Collectively we have identified a novel, integrated, signalling pathway that drives terminal differentiation of osteoblasts. Our findings support earlier predictions (Yoneda 1996) in identifying novel actions of EGF in bone that will lead to advances in the field. Yoneda, T. 1996. Local regulators of bone: Epidermal growth factor – transforming growth factor-α. In Principles of bone biology (ed. J.P. Bilezikian, L.G. Raisz and G.A. Rodan.), pp. 729–738. Academic press Ltd.
Evidence has accumulated in recent years that programmed cell death (PCD) is not necessarily synonymous with the classical apoptosis, as defined by Kerr & Wyllie (J Path, 1973, 111:255–261), but that cells use a variety of pathways to undergo cell death, which are reflected by different morphologies. Although chondrocytes with the hallmark features of classical apoptosis have been demonstrated in culture, such cells are extremely rare in vivo. We have examined the morphological differences between dying chondrocytes and classical apoptotic cells in growth plate and osteoarthritic chondrocytes. Unlike classical apoptosis, chondrocyte death involves an increase in the endoplasmic reticulum and Golgi apparatus. This is likely to reflect an increase in protein synthesis with retention of proteins in the ER leading to expansion of the ER lumen, whose membranes surround and compartmentalise organelles and parts of cytoplasm. The final removal of apoptotic remains does not involve phagocytosis, but a combination of three routes: 1) auto-digestion of cellular material within compartments formed by ER membranes; 2) autophagic vacuoles and 3) extrusion of cell remnants into the lacunae. Together these processes lead to complete self-destruction of the chondrocyte as evidenced by the presence of empty lacunae. The involvement of ER suggests that the endoplasmic reticulum pathway of apoptosis may play a greater role in chondroptosis than receptor-mediated and mitochondrial pathways. Lysosomal proteases, present in autophagic digestion, are likely to be as important as caspases in the programmed cell death of chondrocytes in vivo. We propose the term ‘chondroptosis’ to reflect the fact that such cells are undergoing apoptosis, albeit in a non-classical manner, but one that appears to be typical of programmed chondrocyte death in vivo. Chondroptosis may serve to eliminate cells that are not phagocytosed by neighboring cells, which constitutes a crucial advantage for chondrocytes that are typically embedded in an extracellular matrix. Classical apoptosis in that situation is likely to lead to secondary necrosis with all its disadvantages. This may be the reason why most programmed cell death of chondrocytes in vivo appears to follow a chondroptotic pattern and not the classical apoptotic pattern. At present the initiation factors or the molecular pathways involved in chondroptosis remain unclear.
In addition to the above quantitative changes, qualitative assessment of the data showed an alteration in the loading pattern with reduced push off forces. However, eighteen of the twenty feet showed no alteration in the pattern of pressure distribution.
Aseptic loosening is a growing problem for orthopaedic surgeons and the importance of elevated hydrostatic pressure in its development in vivo is now well documented, but the mechanisms by which pressure could enhance loosening are unclear. We have demonstrated that hydrostatic pressures increased MP synthesis of cytokines, chemokines, PGE2 and M-CSF in vitro, all of which are implicated in bone resorption. 1,25-dihydroxy vitamin D3 (1,25D3) has a pivotal role in bone resorption. It stimulates osteoclastic bone resorption and formation, causes fusion of committed osteoclast precursor cells and activates mature osteoclasts in vitro. Under the correct conditions, macrophages (MP) have the ability to differentiate into osteoclasts. Research has shown that MP can synthesise 1,25D3 and changes in this synthesis occur during MP differentiation. We therefore examined how the application of hydrostatic pressure to MP in vitro influenced their synthesis of 1,25D3. In this study, normal human peripheral blood MP (5x105/ml) were cultured for 7 days then exposed to physiological pressure (34.5x10-3MPa) and/or UHMWPE particles (8mg/ml) and the effect on synthesis of 1,25D3 by endogenous 1a-hydroxylase (1aOHase) was studied. MP were incubated with H3-25, hydroxy vitamin D and 1,25D3 synthesis was analysed by HPLC. 1,25D3 synthesis was increased in cells under pressure by an average of 17% compared to static controls. In situ hybridisation (ISH) was used to demonstrate expression of 1aOHase. Image analysis showed a small increase in 1aOHase mRNA in response to pressure and to particles, and a larger increase to the two stimuli simultaneously. Expressed as % of maximum +Pressure + Particles 100%;+ Particles 59%; +Pressure 37%; No Stimulus < 0.1%. These results suggest that 1,25D3 may be one of the factors which stimulates osteoclastic bone resorption in aseptic loosening. As both these stimuli are likely to be present in vivo, such synthesis could further exacerbate loosening.
All four NSAIDs reduced The effect on adherence was confined to unconditioned PMMA. The effect on biofilm formation and on established biofilms appeared to be related to that on growth and viability. On these grounds, NSAIDs appear to have a limited prospect for use in prevention or treatment of
Interfacial stress distributions in the acetabular region have been studied using plane strain finite element models before and after total hip replacement. The model was adapted from a roentgenogram of a 4 mm slice normal to the acetabulum through the pubic and ilium. The model was divided into 24 regions of different elastic constants with isotropic material properties assumed in each region. The femoral head was modelled as a spherical surface that was mated with a congruent spherical acetabular socket. The implanted hip model was developed by modifying the natural hip model. Contact analyses were carried out between the articulating cartilage layers and between a cobalt chromium head and a cemented ultra-high molecular weight polyethylene (UHMWPE) cup under selected hip contact load cases during normal walking. Local polar coordinates were employed to facilitate the calculation of the interfacial stress components between the cup and cement, cement and subchondral bone as well as between the subchondral and underlying cancellous bones.
The results show that severe reductions in the local stresses in subchondral and cancellous bones were found in the reconstructed case. Both the peak stress and the range of the stress were reduced substantially, suggesting stress shielding in the acetabular region. Load transfer in the reconstructed case was found to occur primarily in the cement layer superior to the cup. Both the peak stress and the stress variation in the cement mantle are substantial, whilst abrupt changes in interfacial stresses occurred between the cement and cup, and cement and subchondral bone. The influence of subchondral bone retention and thickness of the cement (up to 6 mm) on the interfacial stress distribution appears to be insignificant.
The work represents the first stage of research towards developing a numerical tool for pre/post operative assessment of cement/cementless acetabular components.
Joint replacement failure is usually caused by the formation of wear debris resulting in aseptic loosening. Particulate metal and soluble metal ions from orthopaedic alloys (cobalt chromium or vanadium titanium aluminium) that are used in medical prostheses can accumulate in tissues and blood leading to increased chromosome aberrations in bone marrow and peripheral blood lymphocytes. This paper demonstrates that two of the metals used in orthopaedic prostheses, chromium and vanadium can produce delayed as well as immediate effects on the chromosomes of human fibroblasts in vitro. Fibroblasts were exposed to metal ions for only 24 hours and were then expanded over 30 population doublings involving ten passages. The initial increase of chromosomal aberrations, micronuclei formation and cell loss due to lethal mutations persisted over multiple population doublings, thereby demonstrating genomic instability. Differences were seen in the reactions of normal human fibroblasts and those infected with a retrovirus carrying the cDNA encoding hTERT that rendered the normal human fibroblasts telomerase-positive and replicatively immortal. This suggests that chromosomal instability caused by metal ions is influenced by telomere length or telomerase activity. Formerly this syndrome of genomic instability has been demonstrated in two forms following irradiation. One type is non-clonal and involves the appearance of lethal aberrations that cannot have been carried by the surviving cells. The other type is clonal and the aberrations are not lethal. These may arise as a result of complex rearrangements occurring at a high rate post-insult in surviving cells. The consequences of genomic instability are not yet known but it is possible that the increase of chromosomal aberrations that have been previously observed in human patients could be due to immediate and delayed expression of cellular damage after exposure to orthopaedic metals.
Wear debris from worn cobalt chrome joint replacements causes an increase in chromosomal translocations and aneuploidy. In this study the relationship between the amount of DNA damage and the changes in gene expression was investigated in human fibroblasts after exposure to artificial cobalt chrome particles. The comparison was made with different doses of particles, at different time intervals and in fibroblasts of different ages, those that had completed 10 population doublings (10 PD fibroblasts) and those that had completed 35 population doublings (35 PD fibroblasts). The genes (TGF-©¬2, p38 MAPK, Integrin ¥â1, SOD1, Caspase 10, PURA, FRA-1 and VNR) were chosen after a previous screen with cDNA microarrays. The percentage of senescent cells was evaluated using an immunohistochemical assay for ¥â-galactosidase activity. The 35 PD fibroblasts showed significantly more ¥â-galactosidase activity than the 10 PD fibroblasts. The level of DNA damage, as detected with the alkaline comet assay, was greater at higher doses, at longer exposures (up to 24 hours) and in 10 PD fibroblasts. The expression of all the genes listed above was generally lower after exposure to cobalt chrome particles using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The reduction in gene expression, like the increase in DNA damage was greater at higher doses and at longer exposure times. After 24hr exposure the reduction in gene expression was greater in 10 PD fibroblasts compared to 35 PD fibroblasts. After 6hr exposure this was only true at higher doses of particles and the opposite was seen after a lower dose of particles. These results show that levels of gene expression of TGF-©¬2, p38 MAPK, Integrin ¥â1, SOD1, Caspase10, PURA, FRA-1 and VNR may be correlated with the level of DNA damage and that this depends on the dose and length of exposure and the age of the cells. This highlights the potential importance of these genes in the mutagenicity of cobalt chrome particles in human fibroblasts.
Clonal chondrocytes of osteoarthritic (OA) cartilage express an aberrant set of genes. We hypothesize that this aberrant gene expression may be due to clonally inherited epigenetic changes, defined as altered gene expression without changes in genetic sequence. The major epigenetic changes are due to altered DNA methylations in crucial parts of the promoter region. If the cytosines of CpG dinucleotides are methylated, the gene will be silenced, even if the right transcription factors are present. Similarly, de-methylations may activate previously silenced genes. Our aims were to provide ‘proof-of-concept’ data by examining the methylation status of genes in OA vs non-OA chondrocytes. Articular cartilage was obtained a) from the cartilage of fracture-neck-of-femur (#NOF) patients and b) from or around the eroded regions of OA samples. The former was full thickness cartilage, the latter was partially degraded cartilage, which contained mostly clonal chondrocytes as confirmed by histology. The cartilage samples were ground in a freezer mill (Glen Creston, UK) and DNA was extracted with a Qiagen DNeasy maxi kit. To assess DNA methylation status, the genomic DNA was treated overnight with methylation-sensitive restriction enzymes. Cleavage of selected sites was detected by PCR amplifications with primer pairs designed to bracket selected promoter regions. Loss of the PCR band after digestion with the enzymes indicated absence of methylations, whereas presence of the band indicated methylated cytosine. We selected MMP-9 as one of genes that is activated in OA. Transcription of mmp-9 is regulated by a 670 bp sequence at the 5′-end flanking region, which contains 6 CpGs and a further 21 CpGs within the 1.5 kb region further upstream. A PCR primer pair was designed to bracket a 350bp sequence upstream from the transcription start site of mmp-9, which contained four of the six potential methylation sites, cleaved by the methylation-sensitive enzymes AciI and HhaI. DNA from 9 OA patients, 5 #NOF patients and 1 rheumatoid arthritic (RA) patient were digested with HhaI or AciI and examined for the presence or absence of PCR bands. In all patients, digestion with HhaI abolished the PCR band, indicating that the HhaI site was never methylated in either #NOF or OA patients. However, a remarkable difference was found after digestion with AciI: in 8/9 OA patients, the PCR band was no longer detectable, while in 4/5 #NOF patients the PCR band was still present. This suggested that all three AciI cleavage sites were methylated in the majority of chondrocytes from #NOF patients, while at least one of the three AciI cleavage sites was unmethylated in OA patients. Interestingly, the PCR band was present in the RA patient, suggesting methylation of the AciI cleavage sites. The present study provides the first ‘proof-of-concept’ data that suggest epigenetic changes may play a role in the etiology of osteoarthritis. Clearly further work is required to establish the generality of the present findings and whether de-methylations are also found in the promoter regions of other genes that are aberrantly expressed in OA.
It is possible in theory to optimise the geometry of the metallic bearing surfaces, based on the worn components, to minimise the running-in wear. However, such an improvement in lubrication cannot be readily achieved because of difficulties in surgical techniques and position of the components.
Osteoclasts are cells that resorb bone. They derive from haemopoietic precursors in the presence of Macrophage-Colony Stimulating Factor (M-CSF) and the osteoclast growth factor, Receptor Activator of Nuclear Factor–kB Ligand (RANKL). Tumour Necrosis Factor-a (TNF-a) and M-CSF has been shown to form mature osteoclastic bone resorption in vitro murine cultures in the absence of RANKL. The aim of this study was to investigate the mechanism of action of the pro-inflammatory cytokine Tumour Necrosis Factor-a (TNF-a) with respect to osteoclastic bone resorption. Development of osteoclasts was performed using an in vitro assay of healthy human peripheral blood mononuclear culture (PBMNC) in the presence of M-CSF and RANKL. In the same cultures RANKL was replaced by TNF-a over a wide range of concentrations. Osteoclasts were generated in the presence of M-CSF, TNF-a and RANKL from human PBMNC. However, in the same experiments M-CSF and TNF-a in the absence of RANKL failed to support human osteoclast formation. Aseptic loosening and osteolysis are considered the main long-term complications of hip arthroplasty. Pathogenesis of peri-prosthetic osteolysis is multifactorial and both biological and mechanical factors are important. TNF-a is thought to be involved in orthopaedic implant oste-olysis induced by prosthesis-derived wear particles. The final osteolytic step is undertaken mainly by osteoclasts. This is the first report showing that TNF-a and M-CSF in the absence of RANKL in human PBMNC is not capable of inducing osteoclast formation. TNF-a therefore may increase peri-prosthetic loosening by enhancing the activity of the mature osteoclast.
The purpose of this study was to evaluate the effect on movement under load of different techniques of reat-tachment of the humeral tuberosities following 4-part proximal humeral fracture. Biomechanical test sawbones were used. 4-part fracture was simulated and a cemented Neer3 prosthesis inserted. Three different techniques of reattachment of the tuberosities were used – 1)tuberosities attached to the shaft, and to each other through the lateral fins in the prosthesis with one cerclage suture through the anterior hole in the prosthesis, 2)as 1 without cerclage suture, and 3)tuberosities attached to the prosthesis and to the shaft. All methods used a number 5 ethibond suture. Both tuberosities and the shaft had multiple markers attached. Two Digital cameras formed an orthogonal photogrammetric system allowing all segments to be tracked in a 3-D axis system. Humeri were incrementally loaded in abduction using an Instron machine, to a minimum 1200N, and sequential photographs taken. Photographic data was analysed to give 3-D linear and angular motions of all segments with respect to the anatomically relevant humeral axis, allowing intertuberosity and tuberosity-shaft displacement to be measured. Techniques 1 and 2 were the most stable constructs with technique 3 allowing greater separation of fragments and angular movement. True intertuberosity separation at the midpoint of the tuberosities was significantly greater using technique 3 (p< 0.05). The cerclage suture used in technique 2 added no further stability to the fixation. In conclusion, our model suggests that the most effective and simplest technique of reattachment involves suturing the tuberosities to each other as well as to the shaft of the humerus. The cerclage suture appears to add little to the fixation in abduction, although the literature would suggest it may have a role in resisting rotatory movements.
To determine the quantitative adherence and biofilm development of P. acnes on titanium compared to surgical steel. To assess the subsequent effect of penicillin, the therapeutic drug of choice, on mature P. acnes biofilms.
Autologous osteochondral cylinder transfer is a treatment option for small articular defects, especially those arising from trauma or osteochondritis dissecans. There are concerns about graft integration and the nature of tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of quality of repair. The aim was to evaluate cell viability at the graft edge from ex vivo human femoral condyles, after harvest using conventional technique. With ethical approval and patient consent, fresh human tissue was obtained at total knee arthroplasty. Osteochondral plugs were harvested using the commercially available Acufex 4.5mm diameter mosaicplasty osteotome from regions of the lateral femoral condyle (anterior cut) that were macroscopically non-degenerate and microscopically non-fibrillated. Plugs were assessed for chondrocyte viability at the graft edge using confocal laser scanning microscopy (CLSM), fluorescent indicators and image analysis. The central portions of the plugs remained healthy, with > 99% cell viability (n=5). However, there was substantial marginal cell death, of thickness 382 ± 68.2 microm in the superficial zone (SZ). Demi-plugs were created by splitting the mosaicplasty explants with a fresh No. 11 scalpel blade. The margin of SZ cell death was 390.3 ± 18.8 microm at the curved edge of the Acufex, significantly (Mann-Whitney; P= 0.0286; n =4) greater than that at the scalpel cut (34.8 ± 3.2 microm). Findings were similar when the cartilage was breached but the bone left intact. In time-course experiments, the SZ marginal zone of cell death after Acufex harvest showed no increase over the time period 15 minutes to 2 hours. Mathematical modelling of the mosaicplasty surface shows that cell death of this magnitude results in a disturbing 33% of the superficial graft area being non-viable. In conclusion, mosaicplasty, though capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration. There would appear to be considerable scope for improvement of osteochondral transplant techniques which may improve graft-recipient healing and clinical outcomes.
Mechanical load is crucial to maintaining skeletal homeostasis, but the pathways involved in mecha-notransduction are still unclear. The OPG/RANK/ RANKL triumvirate has recently been implicated in bone homeostasis. These molecules, which are produced by the osteoblast (OPG and RANKL) and the macrophage/osteoclast (RANK), modulate osteoclastogenesis. We have previously shown that cyclical hydrostatic pressure influenced synthesis of various molecules by cultured human macrophages. These factors are important in osteoclastogenesis and bone resorption and have been linked to the development of aseptic loosening. We have also demonstrated that 1,25-dihydroxyvitamin D3 (1,25D3) influences macrophage response to pressure. For this study human macrophages were co-cultured with osteoblasts and subjected to cyclical hydrostatic pressure (34.5x10–3MPa [5.0 psi]) for up to five days, with or without 1,25D3 supplementation. Cells were immunostained for RANK and culture media were assayed for sRANKL and OPG using specific ELISAs. Immunostaining for RANK showed that macrophages subjected to pressure or 1,25D3 supplementation synthesised more RANK than controls. In addition, when exogenous 1,25D3 and hydrostatic pressure were administered simultaneously, immunostaining for RANK was more intense. There was a reciprocal relationship between OPG and sRANKL in co-cultures subjected to pressure. If pressure increased synthesis of sRANKL, OPG was decreased. In cultures where pressure decreased sRANKL, a corresponding increase in OPG was seen. In addition, samples from different individuals responded differently to pressure. The majority of cell populations responded to pressure by increasing OPG synthesis, compared to non-pressurised controls. These results demonstrate for the first time that the OPG/RANK/RANKL complex is sensitive to hydrostatic pressure and that 1,25-dihydroxyvitamin D3 might be involved in this response. These findings suggest a possible transduction mechanism for mechanical load in the skeleton, which has implications for future therapies for aseptic loosening and for skeletal abnormalities such as osteoporosis.
High bone density will increase the yield point and stiffness of the femoral head and therefore improve the implant fixation. Cement fixation will increase the yield point and stiffness of the femoral head, especially for the lower density bone compared with cementless fixation.
For yield point, there is no significant difference between cemented or cementless resurfacing (4169 ± 1420 N vs. 3789 ± 1461 N; P = 0.434). However, the high density heads provide a significantly higher yield point than low density heads (4749 ± 1145 N vs. 3208 ± 1287 N; P = 0.01). The addition of cement significantly contributes to femoral head stiffness compared to cementless resurfacing (5174 ± 1730 N/mm vs. 3678 ± 1630 N/mm; P = 0.012).
A phenomenon of methicillin resistance in methicillin sensitive Staphylococcus aureus has been noted in organisms living in biofilm induced by the state of cell wall deficiency. The rate and the amount of biofilm formed by the cell wall deficient organisms far exceeds that of cell wall patent organisms. Once removed from the biofilm the S. aureus had the same sensitivities of the original organism. Cell wall deficient organisms outside the biofilm did not demonstrate the methicillin resistance. A known laboratory strain (ATCC 9144) was induced into a cell wall deficient state and allowed to form biofilm. The rate of formation and amount formed was compared with that formed by cell wall patent organisms. Before inducing cell wall deficiency sensitivity to methicillin was demonstrated using standard microbiological technique. Using an oxacillin containing plate as a culture medium: the biofilm, cell wall deficient organisms and the cell wall competent organisms were inoculated onto separate media. Organisms from the biofilm were isolated and grown free of the biofilm on blood agar. Any growth on the oxacillin containing plate would demonstrate methicillin resistance. There was no growth on the plates containing the cell wall competent or cell wall deficient organisms. There was however growth on the plate inoculated with bio-film, however when organisms were isolated from the biofilm, there was no growth on the media. Antibiotic sensitivities of the original inoculant and the organisms isolated from the biofilm were the same. The biofilm, induced as a result of cell wall deficiency, offers a form of structural protection to the Staphylococcus aureus without altering the resistance pattern of organism. Standard microbiological techniques would therefore report the organism as methicillin sensitive, however clinically the organism may behave as a methicillin resistant organism. The state of cell wall deficiency encourages the formation of biofilm in S. aureus. In-vitro the state of cell wall deficiency is induced using high osmolality media or sub-lethal doses of cell wall active antibiotics. Both these states are found in clinical practice.
Use of allograft in orthopaedic surgery is a well-established procedure. Ethylene Oxide sterilization is still controversial in bone banking because of its effect on osteoinductive properties of bone graft. Freeze drying is considered to be the best technique for allograft preparation and storage. High cost of equipment and its maintenance makes this method not feasible option in developing countries like India. This study involved setting up of a bone bank for the first time in JIPMER institute, Pondicherry, India. Cancellous bone was collected from 40 patients (femoral heads removed during joint replacements). They were cleaned thoroughly, chemically processed and sterilized with ethylene oxide gas and stored doubly packed. These were implanted at 11 patients with 14 non-unions, which required cancellous bone grafts. Patients were followed up clinically looking for infection and radiologically for graft incorporation. 85.7 % of grafted sites were united at the end of 12 months. Non-unions took average of 44.8 weeks for the union. Radiological union achieved by 12 months with average time of graft incorporation 44.8 weeks. In 8 cases the allografts were used to pack cavities. Healing occurred at an average of 29 weeks. In 4 patients with arthrodesis following excision of tumor one site failed to unite, one deep infection, which did not resolve with regular chemotherapy had an amputation. The rest of the sites healed at an average 54.8 weeks. This study shows ethylene oxide sterilized cancellous allograft suitable for packing cavities in treatment of benign bone lesions as well as in treatment of non-union. The osteoconductive property of bone allograft may not be affcted by the ethylene oxide sterilization. Achivement of union and a low rate of infection confirms efficacy of ethylene oxide as cost effective and reliable option for bone allograft sterilization.
Back pain is a major cause of disability and absence from work. 80% of the population will experience back pain at some point in their lives. In our study we looked at 2 randomised groups of patients. Group 1 patients had only epidural steroid injections (ESI) and group 2 patients had ESI plus radiofrequency (RF). We hypothesized that there is no difference in outcome between group 1 and 2 patients. The 2 groups were sent out a retrospective questionnaire which had 5 parts to it, including SF-36 health survey, pain drawing chart, visual analogue scale (VAS), oswestry disability score (ODS) and a patient satisfaction questionnaire. The patients had treatment between 2002 and 2003 and the post-treatment questionnaires were sent out in May 2004. The SF-36 was scored giving a physical component score (PCS) and a mental component score (MCS) using an online scoring website. The groups studied were from 2 different referral hospitals. The patients were randomised by GP referral being sent to the 2 different hospitals. 115 questionnaires with stamped addressed envelopes were sent out to group 1 patients, out of which 71 were returned (61.7%) and 113 to group 2 patients out of which 55 were returned (48.7%). Statistical analysis was done using the SPSS software programme. As there was some evidence of non-normality Mann-Whitney test was carried out, and for the patient satisfaction questionnaire, chi-squared and fisher’s exact test was used. We found that there was a significant difference among the 2 groups in the PCS (p< 0.0005) and MCS (p=0.017). There was a statistically significant difference among the 2 groups in their pain draw score, VAS and ODS with p values of < 0.0005. In the patient satisfaction questionnaire, 8 questions were asked. Patients were asked to assess how successful the spinal injection was. 35 (67%) patients from group 2 said it was successful, compared with 25 (37%) patients from group 1. 9 (17%) patients from group 2 said it was not successful compared with 27 (40%) patients from group 1. 8 (15%) patients were not sure from group 2 and 16 (24%) were not sure from group 1. The difference was statistically significant with a p value of 0.003. When asked whether they would recommend this type of injection, more patients from group 2 said they would (p=0.029). When asked about the duration of effectiveness of the injection, group 2 noticed an increased duration of benefit compared with group 1 (p< 0.0005). There was no significant difference between the groups when asked how many injections were required (p=0.089) or when asked whether or not they required painkillers (p=0.062). However, more patients from group 2 said that painkillers controlled their pain (p=0.001). When asked if they were able to return to work and do housework/gardening after injection, there were significantly more patients from group 2 being able to do so (p< 0.0005). We conclude that in the patients studied, the group who had radiofrequency treatment and epidural steroid injection did better as compared with patients who had epidural steroid injection alone.
All polyethylene tibial components (APT) for total knee joint replacement have been recently reintroduced due to their past success and cost savings with respect to knee designs with a metal backed tibial tray (MBT). However, isolated cases of collapse of the medial bone in APT designs have been observed by the authors prompting this investigation. The objective of this study was to investigate the stress/strain distribution within the cancellous bone for the APT and MBT systems, particularly looking at the effects of coverage of the tray over the proximal tibia in each design. A three-dimensional finite element model of the proximal tibia implanted with a tibia tray was generated. An elliptical cylindrical tibia tray with a peg was modeled as being perfectly bonded to a PMMA layer on the superior surface of the cancellous and cortical bone. Gap size between the edge of the tray and outer of the cancellous bone, was introduced in the medial direction. Load was applied on the superior surface of the tibial insert in the medial side. Two lift-off loading cases were used, a low load of 800N (1 body-weight) and a high load of 3200N (4 x BW), both on the medial side. Permanent plastic deformation and collapse was allowed only in the cancellous bone, while all other materials were modeled elastically. Under low load conditions within the elastic limit, introducing a gap between the tray and the cortical bone produced a stress/strain intensity in the cancellous bone beneath the edge of the tray. The strain in the cancellous bone within the APT design was generally 3 times greater than the MBT design, however, peak strain values were similar at the edge of the tray. Whilst the strain increased with the introduction of a gap the resulting strain was not sensitive to the gap size for both designs. Under high load conditions, permanent plastic deformation and bone collapse were observed in the cancellous bone at the edge of the tibial tray in both designs where a gap was introduced. The maximum strain in the cancellous bone was found to be more sensitive to the gap size for the APT design than the MBT design. This can be contributed to the difference in the load transfer through the cancellous bone in the two designs. The MBT design with the more rigid tibial tray transfered higher load through the outer cortical bone than the APT design. The less rigid APT design resulted in progressive collapse of the cancellous bone beneath the tray. Particularly significant was the volume of highly stressed cancellous bone which was 4 times greater in the APT design compared to the MBT design. The results suggest that coverage may be a more important parameter for the APT design than the MBT design. The APT design may, therefore, be more suited to patients with better bone quality.
Distal radial fractures account for 17% of all fractures treated, with peaks in the bimodal distribution corresponding to young and senior patients. External fixation is one of the best techniques to allow quick patient recovery and is necessary for complex fractures, such as that of the distal radius. However, the safe removal time for these frames remains unclear. A conservative approach commonly leaves the external fixator in place for six weeks, which may be unnecessarily prolonged and lead to increased complications. The aim of this work is to develop a technique to quantify, objectively, a safe removal time for these frames. Studies have been conducted on external fixation of tibial fractures, however there are differences that do not allow transfer of these studies to the external fixation of distal radial fractures. These differences include configuration of the fixation frame, bone and fracture geometries, and the application and transfer of the load to the bone. In this work, the dynamic transfer of the load between the fractured bone and the fixator is investigated. An instrumented grip and a measuring device have been developed to monitor the axial force and displacement when the patient applies a load. Using measurements collected by the instrument and data specifying the frame geometry, a finite element model is used to calculate the load carried by the fixator and by the bone, and the rigidity of the new callus is determined. Plotting the rigidity on semi-logarithmic scale the healing rate can be established. This technique has been successfully verified in a laboratory simplified structure representative of bone fracture. The rigidity of several intra-gap materials has been estimated experimentally using the technique, and the results compared to the real value of the material. These measurements do not interfere in any way with the patient treatment and they can be collected from the first day after the operation. The technique has been tested on 14 volunteer patients and the increase in callus rigidity can be detected by measurements during treatment using the technique described. A randomised prospective study has been initiated to validate this technique and investigate the healing process. A positive outcome would enable the rigidity of the new callus bone and the healing rate to be monitored during clinical assessment. Any healing delay or non-union could be promptly detected, improving the quality of the treatment.
During conventional hip arthroplasties, the diseased femur is rigidified using a metallic stem. The insertion of the stem induces a change in the stress distribution in the surrounding femur, and the bone remodels; this stress distribution is a direct result of the stem stiffness characteristics. Healthy healing of the femur requires that the bone be loaded as naturally as possible. If the bone is not loaded appropriately, it can resorb which may result in stem loosening and revision. Although current rigid metallic femoral stems are very successful, a poor stress distribution may become a critical problem for younger patients as the stem/femoral bone construct will be subjected to higher loads for longer times, and since remodelling is faster, loosening can occur earlier. Reduced stiffness stems have therefore been investigated, but early failures have been reported due to increased movements, poor initial stability and the low proximal stiffness of the stem. A novel biocompatible carbon fibre reinforced plastic (CFRP) stem has been developed in light of these past experiences
Measuring strain in biological specimens has always been inherently difficult due to their shape and surface properties. Traditional methods such as strain gauges require contact and therefore have reinforcing effects, also the surface preparation can be time consuming and if proper fixation is not achieved the results will be inaccurate. Using a non contact method to measure strain such as photogrammetry has several advantages. The strain over the whole surface of a specimen can be mapped, depending on the field of view of the camera used. It has a large dynamic range, from microns to millimetres which can be decided upon at the post processing stage. Specimens can be tested to destruction without damaging any measurement equipment. Also there is considerably less set up time involved between testing different specimens once the system is in place. We aimed to test speckle photogrammetry, a method used in industry and fluid dynamics as a tool for assessing proximal femur fracture stability and repair techniques. A Zwick Roell materials testing machine was used to axially apply a staircase loading pattern to sawbones femora, simulating the load experienced by the femur when standing. Firstly an intact bone was tested then a set of three identical fractures of each of three common fracture configurations were produced by osteotomy. The first femur of each configuration was loaded un-repaired to failure; the remaining two were repaired using common techniques for that particular fracture type then also loaded to failure. The bone and fixation device were covered with stochastic, high contrast paint speckle prior to testing. This speckle pattern was recorded at regular load intervals by a digital camera which was attached to the materials testing machine via a rigid frame to eliminate any camera movement. These images were then transferred to a computer where they were converted to 8 bit bitmap images. Matlab was used to process the data from subsequent images to produce vector and colour maps of the displacements and strains over the entire visible surface of the proximal femur and to show the comparative displacements and strains experienced by the individual bone fragment and the fixation devices. Non contact optical strain measurement has proved itself to be a useful tool in assessing the stability of fractures and the repair techniques of these fractures. Additionally it can also be used to validate finite element models to compare theoretical and experimental results due to the similar data and graphic visualisation outputs which are produced by both techniques.
Conventional fixed-bearing (FB) knee prostheses have been proved clinically successful. Rotating platform, mobile-bearing (MB) total knee replacements (TKR) have been developed to improve knee kinematics, lower contact stresses on the polyethylene tibial component, minimize constraint, and allow implant self-alignment. The purpose of this study was to characterize and compare the functional outcome of FB- and MB- TKR during gait and deep knee bends, using a motion analysis system. Two groups of five patients with a unilateral FB TKR (PFC) or MB TKR (LCS) underwent a gait analysis study. The normal contralateral limb was used as a control to compare data in the stance phase of gait. Demographic, clinical, and radiographic data were equivalent in the 2 groups. Both MB and FB TKRs gave good functional results in spite of different design rationales. No statistically significant difference was demonstrated between the two groups. However, gait and knee function after TKR was abnormal even though the patients were asymptomatic. A flexional pattern for flex-ion-extension moments at the knee during level walking was present in both types of TKR. Differences in rotational moments between the two groups were observed, with a higher internal rotational moment in the PFC group (PFC, 0.14 Nm/kg; LCS, 0.09 Nm/kg; p=0.094). A stressful weightbearing activity, such as deep knee bends, amplified the functional differences between the different prosthetic designs, indicating that knee kinematics are activity-dependent. Kinetic and kinematic differences noted between the 2 groups reflect different patterns of joint surface motion and loading, with postulated effects on long term failure of the implants through wear, mechanical failure, and loosening. Gait analysis using external skin markers has a limited role in the characterization of the joint surface motion of the prosthetic knee during ambulatory activities because of errors and assumptions inherent in the technique. However, it provides scope for the study of kinetic parameters acting on different knee prostheses during gait.
Osteomyelitis commonly causes bone destruction and is most frequently due to infection by Staphylococcus aureus.
Bone microhardness has been successfully correlated with important functional parameters such as mineralisation and stiffness. It provides a means of examining the mechanical competence of bone at a micron scale, averaging the effect of osteonal lamellae but sensitive to variation in mineral content within a bone, and, with careful selection of indentation site, able to obtain material characteristics separate from any effects of porosity. However, the effect of bone’s viscoelasticity on such measurements has been largely ignored. This preliminary study investigates the post-indentation size change of Vickers indentations on wet bone. 4 axial slices of bovine femur were harvested from the same shaft, and polished. Each sample was subjected to 4 sets of 10 Vickers indentations with a load of 50 g and holding period of 15 s. The indentation size was measured immediately after the load was removed, and then again at intervals for a period up to 24 hours after the indentation was made. To avoid dehydration, the bone stood in water during the indentation testing and during measurement, and between each measurement period it was fully immersed in water. Measured hardness significantly decreased with time, by approximately 30% in total. The rate of post-indentation recovery is difficult to analyse since the driving force of residual strain decreases as recovery takes place. However a simple exponential fit to the variation of HV with time in the form of H = H(final).(1−exp(−kt)) + H(initial) suggests that the size of the indentation tends towards a constant size between 5 and 24 hours after indentation. Thus we conclude that care should be taken when making “early” measurements given the rapid rate of change in indentation size. Caution should also be employed when interpreting such data.
Cortical porosity is a useful evaluator of bone since it is sensitive to changes in bone turnover. The aim of this study was to evaluate cortical bone porosity of human vertebrae samples using Scanning Acoustic Microscopy (SAM). Currently the common techniques used to determine bone porosity are histomorphometry or scanning electronmicrosopy images. Both methods require extensive preparation of the bone samples. SAM represents a new technique with the great advantage of minimal sample interference since the bone is imaged in water, or saturated, and requires just one flat surface which is scanned (but not contacted) by the transducer. 46 specimens between the ages of 64–90 years were randomly selected and ground before SAM imaging of was carried out using a 400 MHz transducer. For each sample posterior and anterior sections of the cortical bone were scanned several times, and the porosity measured using Scion image software to process the images. It was possible to image the entire anterior or posterior cortex in a single image with 4 mm spatial resolution. Measured porosity was in the region 5 % – 21 %, and showed a significant increase with age for the female specimens but no age dependence in the male specimens. At low porosity (< 6 %) vertebral compressive strength was uncorrelated with porosity. However, at higher porosities strength was highly correlated with porosity. (As would be expected, strength decreased with increasing porosity). High frequency SAM has potential for future bone characterisation, particularly where it is desirable to correlate local measurements of material properties such as nanohardness or microhardness, with microstructure.
Since cementless stem fixation in hip arthroplasty is becoming more and more common, the overall incidence of intraoperative femoral fractures has risen considerably. Depending on primary or revision arthroplasty, literature reports fracture rates between a few percent up to one third of the cases.
In this study, methods commonly applied in the field of structural testing were customized for this specified interference fit situation. A cementless hip system (ABG II, Stryker) was used on animal bones and biomechanical bones.
Transient excitation in the form of regular hammer strokes and sinusoidal excitation using a shaker served as an input. The output of the system under test was measured on the greater trochanter using a piezoelectric accelerometer.
The signals were digitized with a high-speed data acquisition system and analyzed in real-time with spectrum analysis software.
Analysis included threshold detection in the time domain to determine the time delay between the input and output transducer. Spectrum analysis in the frequency domain included FFT analysis and frequency response function analysis to identify shifts of fundamental frequencies and harmonics to describe the vibrational changes with increasing stability.
A digital imaging system was set up to take pictures of the metal-bone site to measure inducible displacement with each hammer impact and correlate it with the vibrometry results. Furthermore a strain gauge circularly mounted around the proximal femur monitored accurately any hairline fracture.
This study shows that changes of the vibrational spectrum are directly related to implant fit. The range of interest is well in the sonic range, which apparently is the reason for many surgeons to listen and ‘feel’ carefully during advancing the broach or the final implant into the femur.
The study is trying to extract critical vibrational parameters correlated with stability and femoral integrity. Due to the different dimensions of the tested animal bones and lack of soft tissue damping, further experiments on cadavers need to be carried out.
Vibrational spectrum analysis could prove to be a useful tool to readily assess implant stability and femoral integrity. It seems to be most beneficial in revision surgery or minimally invasive hip replacement, where the risk of femoral fractures is increased or fissures could easily be missed.
the circumference of the anatomical neck; (H) as the most superior point of the articular surface at the insertion of the supraspinatus tendon, (L) as the corresponding lowest point of the articular surface at the cartilage/calcar interface; The medial (MC) and lateral (LC) humeral condyles were exposed and delineated with k-wires.
A Microscribe 3D-X digitizer was used to digitize the points and lines. The data for each humerus were imported into Rhinoceros NURBS modelling software and graphically represented. The constructed graphical model was used to divide the articular portion of the humeral head into six equal sections in the axial plane. The retroversion angle, relative to the epicondyles, was calculated for each section.
Intervertebral disc function and dysfunction is governed by its structural architecture of concentric layers of highly ordered collagen fibres. This architecture is important at the mm scale for overall mechanical performance of the disc; and at the micron scale for mechano-transduction signalling pathways of the disc cells that are responsible for matrix maintenance and therefore disc health. To understand such mechanical behaviour 3-dimensional collagen fibre architecture must be quantified in intact intervertebral discs. Conventional imaging modalities lack either the spatial resolution (e.g. x-ray diffraction) or penetration (e.g. optical, electron or confocal laser microscopy) to yield mechanically important information. Preliminary studies of scanning acoustic microscopy (SAM) at 50 MHz visualises alternating layers of fibre texture, however exactly what is being imaged requires both explanation and validation. Three-dimensional SAM data sets obtained from intact discs were compared to polarised-light and scanning electron micrographs of individual layers of fibres, peeled by micro-dissection from discs. The dimensions of the structural features were measured and recorded. Optical and electron microscopy revealed that each layer consisted of highly oriented collagen fibres of diameter 5 μm with regularly spaced splits between fibres with a spacing of approximately 20–30 μm. The SAM data sets showed layers with a uniform highly oriented fibre texture that reversed between adjacent layers. Resolution of the texture was limited by the acoustic system to approximately 30 μm. It is clear that SAM at 50 MHz cannot resolve and therefore image individual collagen fibres. However, the regular defects in the fibre layers can be visualised and convey complete information about local collagen fibre architecture. SAM therefore provides an effective way of quantifying the fibrous structure of intact, hydrated, unfixed intervertebral discs.
This study aimed to explore the relationship between the geometry of the tuberosity located superior to the Achilles tendon enthesis and the thickness of its fibro-cartilaginous periosteum. The tuberosity acts as a pulley for the tendon during dorsiflexion of the foot and is thus compressed by the overlying tendon. This can result in pressure-related injuries which account for a significant number of Achilles-related problems among sportsmen or women. We postulated that variations in the contact area between the tendon and the tuberosity (and consequently the pressure exerted by the tendon) affects the periosteum thickness. Here, we report four methods of portraying the two dimensional geometry of the superior tuberosity. Material was obtained from 10 elderly dissecting room cadavers donated to the Cardiff University for anatomical examination and prepared for routine histology. Serial sagittal sections were collected at 1 mm intervals, and stained with Masson’s trichrome, toluidine blue and haematoxylin & eosin. In the first method, the area of the bursal cavity was measured between the deep surface of the tendon and the tuberosity within a 9mm radius of the proximal part of the attachment site. The second technique was similar, though used the long axis of the tendon as a reference, rather than its deep surface. The third technique measured the area of the tuberosity within 20 degrees of the tendon long axis. The final technique measured the cumulative gradient of the first 5 mm of the tuberosity, with reference to the tendon long axis. The periosteum thickness was measured at 500 μm intervals from the proximal part of the enthesis and mean values calculated. A good correlation was seen between all techniques, with the tuberosities having the most localised area of contact with the tendon, showing the thickest periosteum.
The present study investigates the repeatability of two new methods of measuring acetabular wear with differing levels of automation. Experimental evaluation showed that the more automated method was more repeatable. Both methods segmented the femoral head and acetabular rim with ellipses. The displacement of the ellipse centres was measured and the difference at year 1 and 5 taken as a measure of wear. Measurements were obtained twice for each case. The less automated of the two methods involved the annotation of 9 points on the femoral head and 18 on the acetabular rim to which two least squares ellipse fits[
Surgical site infection (SSI) is an important outcome indicator. It is estimated that 70% of post-operative infections present after discharge. A reliable post-discharge surveillance (PDS) method is yet to be described. The aim of this prospective cohort study was to assess the reliability of patient self-diagnosis. Telephone questionnaires were used following hip and knee prosthetic surgery. A trained validation nurse checked the wounds of all patients reporting problems and a sample of those who did not. 376 elective hip and knee arthroplasty procedures from 363 patients were included. In-patient infection rate was 3.1% (13 of 422 procedures) and post-discharge infection rate was 5.2% (22 of 422 procedures). Results suggest that patients can reliably self diagnose SSI. The sensitivity of the procedure (the probability that the telephone surveillance will detect an infection given that the patients has an infection) was 90.9%. The specificity (the probability that the telephone surveillance will report no infection given that no infection is present) was 76.6%. Hence telephone PDS of SSI is a valuable means of identifying accurate rates of hospital acquired infection following surgery. In this study population, 41% of infections were diagnosed post discharge, which is lower than has previously been estimated. PDS of SSI is necessary if accurate rates of hospital acquired infection following surgery are to be available.
The demographic challenges of an advancing aged population emphasise the need for innovative approaches to tissue reconstruction to augment and repair tissue lost as a consequence of trauma or degeneration. Currently, the demand for bone graft outstrips supply, a key issue in the field of revision hip surgery where impaction bone grafting of the femur and acetabulum has impressive results in the short and medium term but often requires up to 6 donated femoral heads. Spine and selected tumour and trauma cases are also eminently suitable for this mode of bone stock replacement. In the current study, we examined the histological and biochemical findings of two parallel in-vitro and in-vivo studies using human mesenchymal stem cells on synthetic scaffolds for possible bone augmentation. The first study confirmed that culture expanded bone marrow cells from 3 patients (mean age 76 +/−4) could be successfully seeded onto washed morsellised allograft. The seeded graft was then exposed to a force equivalent to a standard femoral impaction (impulse=474 J/m2) and cultured for 4 weeks in osteogenic media. Examination of cell viability using cell tracker green and ethidium homodimer-1 and confocal microscopy confirmed extensive cell proliferation and viability following impaction and culture. Alcian blue/ Sirius red confirmed matrix production, alkaline phosphatase immunocytochemistry production of enzyme activity and Goldners trichrome enhanced osteoid formation. The second study compared 3 scaffolds; bone allograft, a ß – Tricalcium Phosphate (ß-TCP) graft substitute and a 50:50 mixture of allograft and ß-TCP. The scaffolds were seeded with either immunoselected STRO-1+ human mesenchymal stem cells or unselected marrow cells. The scaffolds were similarly exposed to impaction forces and cultured for 4 weeks in vitro or in vivo, implanted subcutaneously in MF1nu/nu mice. Both studies demonstrated cellular viability, activity and osteogenesis as assessed using confocal microscopy, Goldners trichrome and alcian blue/Sirius cytochemistry. The demonstration of enhanced osteoid formation as a consequence of stem cell proliferation after impaction grafting augers well for the success of autologous stem cell implantation on impacted graft substitute with or without the addition of morsellised allograft. The implications therein for clinical use in the future await clinical trials.
Idiopathic osteoarthritis (OA) is a complex, late-onset disease whose causes are still unknown. In spite of tremendous efforts, the search for the genes pre-disposing towards osteoarthritis has so far met with little success. We hypothesize that epigenetic changes play a major role in the pathology of OA. Epigenetics refers to stable, heritable, but potentially reversible modifications of gene expression that do not involve mutations in the DNA sequence, for example DNA methylation or histone modification. Epigenetic changes are gene and cell-type specific, may arise sporadically with increasing age or be provoked by environmental factors. To investigate whether epigenetic changes are significant factors in OA, we examined the DNA methylation status of the promoter regions of three genes that are expressed by OA, but not by normal, articular chondrocytes, namely MMP-3 (stromelysin-1), MMP-9 (gelatinase B) and MMP-13 (collagenase3). We hypothesized that these genes are silenced in normal chondrocytes by methylation of the cytosines of CpG dinucleotides in the respective promoter regions, but that abnormal expression is associated with a de-methylation, leading to eunsilencing f of gene expression. Cartilage was obtained from the femoral heads of 16 OA and 10 femoral neck fracture (#NOF) patients, which served as controls due to the inverse relationship between osteoporosis and OA. The cartilage was milled in a freezer mill with liquid nitrogen, DNA was extracted with a Qiagen kit, digested with methylation sensitive restriction enzymes, followed by PCR amplification. These enzymes will cut at their specific cleavage sites only if the CpGs is not methylated and thus allow us to determine methylation status of specific CpG sites.
In osteoarthritis (OA) there is a loss of matrix components, especially aggrecan, which is a major structural component important for the integrity and function of articular cartilage. The breakdown of aggrecan is mediated by enzymes from the ADAM-TS (a disintegrin and metalloproteinase with thrombospondin motifs) family and recent studies have suggested that, in humans, ADAM-TS4 (aggrecanase-1) plays a major role. Articular chondrocytes do not express ADAM-TS4 in contrast to clonal OA chondrocytes. Since in any somatic cell non-expressed genes are thought to be silenced by DNA methylation in the promoter region, the aims of the project were twofold:
to localize enzyme expression for ADAM-TS4 by immunocytochemistry and to determine whether ‘unsilencing’ (i.e. DNA de-methylation) in the promoter of ADAM-TS4 was associated with the abnormal enzyme synthesis.
Using immunocytochemistry, we confirmed that there is an increased expression of ADAM-TS4 in OA chondrocytes, which initially occurs in chondrocytes of the superficial zone. As the Mankin score increases, ADAM-TS4 positive chondrocytes were found in duplets, then quadruplets until, at Mankin score > 10, all the cells in a typical OA clone were immunopositive for ADAM-TS4, suggesting that abnormal enzyme expression was inherited by daughter cells. DNA was extracted from femoral head cartilage of 24 patients, who had undergone hip replacement surgery for either symptomatic OA or following a fracture of neck of femur (#NOF). The latter was used as control due to the inverse relationship between OA and osteoporosis. For OA samples, it was important to sample only those regions for which immunocytochemistry had shown the presence of ADAM-TS4 synthesizing cells, i.e. the superficial zones near the weight-bearing region. DNA methylation only occurs at cytosines of the sequence 5′...CG...3′, the so-called CpG sites. To determine methylation status of specific CpG sites, methylation sensitive restriction enzymes were used, which will only cut DNA in the absence of methylation. By designing PCR primers that bracketed these sites, presence or absence of PCR bands could distinguish between methylated and non-methylated CpGs respectively. The ADAM-TS4 promoter contains a total of 13 CpG sites. Using restriction enzyme/primers combinations, it was possible to analyze 7 of these sites for methylation status. In the control group, all 7 CpG sites were methylated, while there was an overall 49% decrease of methylation in the OA group (p=< 0.0001). Some of the CpG sites were more consistently demethylated then others, one site at −753bp upstream from the transcription start site, showed a 86% decrease in methylation in OA compared to the control group (p=0.0005), while at other sites the decrease in methylation ranged from 36–50%. Conclusions. This study confirmed by immunocytochemistry that ADAM-TS4 is produced by OA chondrocytes, contributing to the degradation of their matrix. This abnormal enzyme expression is associated with DNA methylation. If a causal relationship could be proven in the future, then DNA de-methylation might play an important role in the pathogenesis of osteoarthritis and future therapies might be directed at influencing the methylation status.
NSAIDs inhibit fracture repair, yet the mechanism behind this effect is unknown. It is recognised that NSAIDs impede tumour growth via an inhibition of angiogenesis, primarily via a COX-2 pathway. We propose that the inhibition of fracture repair is via a similar mechanism and have investigated this hypothesis using a murine fracture model. 225 animals were randomised into either treatment (rofecoxib) or control groups and underwent a standard open femoral fracture treated using an external fixator. Outcomes measures involved assessment of healing using radiographic, histolological and biomechanical means; and measurement of blood flow across the fracture gap using Laser Doppler Flowmetry. X-ray analysis showed a similar healing pattern in both groups, however at days 16 and 32 the NSAID group had significantly poorer healing. Histological analysis showed that controls healed quicker (significant at days 24 and 32); and had more bone but less cartilage at day 8. Biomechanical testing showed controls were statistically stronger and stiffer at day 32, while NSAID animals had a significantly greater rate of fixation failure, leading to loss of pin-bone osseointegration; this occurred primarily before day 16. There was no difference in blood flow between the groups on the day of surgery, and both groups exhibited a similar flow pattern; NSAID animals however, exhibited a lower median flow from day 4 onwards, which was significantly poorer at days 4, 16 and 24. Positive correlations were demonstrated between a higher blood flow and both the histological and radiographic results. While NSAIDs were seen to inhibit fracture repair in all outcome measures; and were also noted to decrease blood flow at the fracture, with strong negative correlations being noted between NSAID prescription and fracture repair; multiple regression analysis suggest that this negative effect of NSAIDs on healing is independent of its inhibitory action on blood flow. COX-2 inhibitors are marketed as having cleaner side effect profiles and prescribing is on the rise. Recently however some of the newer COX-2 specific inhibitors have been removed from the market as their seemingly clean side effect profile has come under scrutiny. We have demonstrated that the COX-2 specific inhibitor rofecoxib does has a significant negative effect on fracture repair; and as hypothesised that it also has a significant negative effect on blood flow at the fracture site. While these outcomes strongly correlate, the mechanism behind the effect remains to be elucidated, as we have also demonstrated that these modalities are independent of each other.
Joint pain, as a consequence of cartilage degeneration or trauma results in severe pain or disability for millions of individuals worldwide. However, the potential for cartilage to regenerate is limited and there is an absence of clinically viable cartilage formation regimes. Cartilage is composed of only one cell type, is avascular and has a relatively simple composition and structure, thus cartilage tissue engineering has tremendous potential. Therefore, to address this clinical need, we have adopted a tissue engineering approach to the generation of cartilage ex vivo from mesenchymal cell populations encapsulated in polysaccharide templates form alginate and chitosan that favours chondrogenesis, and cultured within perfused or rotating bioreactor systems. To drive the chondrogenic phenotype, alginate beads were encapsulated with isolated human bone marrow cells, human articular chondrocytes or a combination of both in a 2:1 ratio, with the addition of TGF-â3, and placed in either a Synthecon rotating-wall bioreactor, perfused at a flow rate of 1ml/hour, or held in static conditions for 28 days. Alcian Blue and Sirius Red staining indicated ordered, structured and even cell distribution within capsules from the rotating bioreactor system in comparison with perfused and static conditions. Furthermore, alginate beads encapsulated with mixed cell populations that were cultured under static and rotating-wall conditions revealed positive staining for both collagen and proteoglycan, and with areas that closely resembled the formation of osteoid. Cell viability, assessed using the fluorescent dye Cell Tracker Green, indicated a higher proportion of metabolically active cells in capsules from the rotating-wall bioreactor than perfused or static under the conditions examined. Immunohistochemistry indicated the expression of type II collagen, SOX9 and C-MYC in samples from all conditions after 28 days. C-MYC is implicated in cell proliferation and differentiation and type II collagen and SOX9 are cartilage-specific markers. Biochemical analysis revealed significantly increased (p < 0.05) protein in samples encapsulated with mixed cell populations compared with alginate samples that were encapsulated with either bone marrow or chondrocytes. There was also a significant increase in protein in all samples that were cultured in the rotating-wall bioreactor in comparison with perfused or static conditions after 28 days. A significant increase in DNA was observed in the rotating-wall than perfused or static for the bone marrow cultures. Interestingly in chondrocyte cultures perfused conditions were found to result in significantly higher DNA than rotating-wall and static, and static conditions resulted in significantly higher DNA for alginate encapsulated with mixed cell populations. The current studies outline a tissue engineering approach utilising progenitor populations, bioreactors and appropriate stimuli to promote the formation of cartilage within a unique innovative polysaccharide capsule structure, and indicate the potential of rotating-wall systems to promote cartilage formation. Understanding the conditions required for the generation of functional cartilage constructs using such bioreactor systems carries significant clinical potential.
Viscosupplementation is the current treatment modality for early stage arthritis and in some cases for delaying joint replacement procedures. Rheological properties similar to that of synovial fluid and high molecular weight have been recognized as the determining factors in hyaluronic acids (HA) therapeutic and analgesic value (
Leucocytes represent a very important host defence against a number of invading pathogens and neoplasia. However, the activity of phagocytic leucocytes has been heavily implicated in the development of ischaemia-reperfusion injury, and as an aetiological factor in the pathology of other clinically important inflammatory conditions. Ischaemia-reperfusion injury occurs in diseases such as stroke and ischaemic heart disease (IHD), and during surgical procedures such as orthopaedic surgery. Investigations presented here employed a model of tourniquet-induced forearm ischaemia-reperfusion injury to investigate the effect on leucocyte adhesion and trapping (n=20). Neutrophil and monocyte leucocyte subpopulations were isolated by density gradient centrifugation techniques. Neutrophil and monocyte cell surface expression of the adhesion molecule CD11b was measured by labelling with fluorescent anti-CD11b monoclonal antibody via flow cytometry. Plasma concentrations of the soluble intercellular adhesion molecule-1 (sICAM-1) and soluble L-selectin (sL-selectin) adhesion molecules were measured using commercially available ELISA kits. Leucocyte trapping was investigated by measuring the concentration of leukocytes in venous blood leaving the arm. During ischaemia-reperfusion there was an increase in CD11b expression on neutrophils (p=0.040) and monocytes (p=0.049), a decrease in sL-selectin (p=0.387) and sICAM-1 (p=0.089) concentrations, and a decrease in peripheral blood leucocyte concentration (p=0.019). Evidence of increased leucocyte adhesion and trapping during ischaemia-reperfusion injury was supported by an increase in CD11b cell surface expression of neutrophils and monocytes. CD11b is expressed on phagocytic leucocytes and binds to ICAM-1 expressed on the surface of vascular endothelium. This increased expression of CD11b on leucocytes may therefore play a central role as the mechanism by which leucocyte trapping in the microcirculation occurs. The measured decrease in plasma concentration of sICAM-1 and sL-selectin suggests that these adhesion molecules retain their functional activity, and may bind to their corresponding cell surface ligands. It is therefore reasonable to believe that ICAM-1 expressed on the endothelium and L-selectin expressed on leucocytes is also binding to their corresponding cell surface ligands. A decrease in the number of leucocytes in the peripheral circulation may be due to increased trapping of leucocytes in the microcirculation. When leucocytes become trapped their concentration in blood leaving the microcirculation decreases, resulting in the measured decrease in leucocyte concentration. In conclusion, this study confirms the important role of leucocytes during ischaemia-reperfusion injury, which could allow for the possibility of future research that may provide therapeutic intervention for inflammatory conditions.
Crush injury is one of the categories of nerve injury, which is often encountered in the clinical field. There is no doubt that crushed nerves, which have anatomical continuity, regenerate spontaneously and somehow reinnervate their target tissues, such as muscle and skin. However, the longer it takes to reinnervate the target tissues, the more profoundly the atrophy of these target tissues progresses, resulting in a poor outcome. Clinically, it is therefore crucial to accelerate nerve regeneration if excellent results are to be achieved. Hepatocyte growth factor (HGF) is well known to be involved in many biological functions, such as organ regeneration and angiogenesis, and to exert neurotrophic effects on motor, sensory, and parasympathetic neurons. This raised hopes that HGF protein might be useful for the clinical treatment of nervous system disorders. However, administration of HGF as a recombinant protein is still beset by a number of problems, such as a short serum half-life and poor access to the central nervous system by the systemic route because of the presence of the blood-brain barrier. These problems can be major obstacles to the therapeutic use of such factors, and this has highlighted the need to develop innovative therapeutic strategies for more efficient delivery into the nervous system. Gene transfer into the nervous system has enormous therapeutic potential for a wide variety of disorders. It appears to have advantages over the administration of single or multiple bolus doses of a recombinant protein because gene transfer can achieve an optimally high, local concentration within the nervous system. Recently, two different strategies have been reported. Firstly gene transfer by local intraneural injection and secondly gene transfer via retrograde axonal transport. In crush injury, it is well known that some axons in the crushed nerve can remain intact. It is from this evidence that the idea of performing gene transfer via retrograde axonal transport arose. In this study, we gave repeated intramuscular injections of the human HGF gene, using nonviral HVJ (Hemagglutinating Virus of Japan) liposome method, to examine whether transfection of the rat nervous system with this gene is able to exert neurotrophic effects facilitating recovery of a crushed nerve. The expression of HGF protein and HGF mRNA indicated that gene transfer into the nervous system did occur via retrograde axonal transport. At 4 weeks after crush, electrophysiological examination of the crushed nerve showed a significantly shorter mean latency and a significantly greater mean maximum M-wave amplitude with repeated injections of HGF gene. Furthermore, histological findings showed that the mean diameter of the axons, the axon number and the axon population were significantly larger in the group with repeated injections of HGF gene. The above results show that repeated human HGF gene transfer into the rat nervous system is able to promote crushed-nerve recovery, both electrophysiologically and histologically, and suggest that HGF gene transfer has potential for the treatment of crushed nerve.
Tissue loss, as a result of injury or disease, provides reduced quality of life for many and with an increasingly ageing population there is a greater requirement for skeletal repair strategies. An emerging attractive approach, tissue engineering, is based on the use of an appropriate source of progenitor cells, a scaffold conducive to cell attachment and maintenance of cell function and the delivery of appropriate growth factors. As a cell source, mesenchymal stem cells (MSCs) or marrow stromal cells derived from adult human tissues offer tremendous potential for tissue regeneration. However, to date, the plasticity, multipotentiality and characteristics of potential stem cells from fetal skeletal tissue remain poorly defined. We have examined, in preliminary studies, the multipotentiality and phenotypic properties of cell populations derived from human fetal femurs collected at 8–12 weeks post-conception in comparison to adult-derived mesenchymal stem cell populations including those isolated using STRO-1 immunoselection. Fetal cells were culture expanded from explants in basal media then maintained for periods of up to 28 days in monolayer cultures in adipogenic and osteogenic conditions. Cells were also maintained in chondrogenic conditions via the pellet culture method, maintained in established media conditions including TGF-â3, with cultures taken to 7, 14, 21 and 28 days. Adipocyte formation was confirmed by morphology: large amounts of lipid accumulation were observed by Oil Red O staining and aP2 (FABP-3) immunocytochemistry. Osteogenic differentiation was also confirmed by Type I Collagen immunocytochemistry. The growth of fetal cells on biomimetic scaffolds and their osteogenic activity was confirmed by confocal microscopy and Alkaline Phosphatase staining respectively. In chondrogenic conditions, chondrocytes were embedded within lacunae and extensive matrix deposition was observed using Alcian blue/Sirius red staining. The chondrogenic phenotype was confirmed by positive staining via SOX9 immunocytochemistry. Differentiation and proliferation were accelerated in fetal populations compared to adult-derived immunoselected MSCs. Plasticity of fetal cells has been demonstrated by the formation of large numbers of adipocytes within osteogenic populations. In summary we demonstrate the proliferative and multi-potential properties of fetal-derived chondrocytic cells in direct comparison to adult-derived MSCs including STRO-1 immunoselected populations. Given the demographic challenges and ethical issues surrounding current embryonic cell research, fetal cell populations may also provide a unique half-way model to address stem cell differentiation in comparison to adult cells. Elucidation of immunogenecity and selective differentiation will confirm the potential of these fetal cells as a unique alternate cell source for therapeutic approaches in the restoration of damaged or diseased tissue.
Dual energy X-ray absorptiometry (DXA) is a precise tool for measuring bone mineral density (BMD) around total joint prostheses. The Hologic ‘metal-removal hip’ analysis package (Hologic Inc, Waltham, Massachusetts) is a DOS-based analysis platform that has been previously validated for measurement of pelvic and proximal BMD after total hip arthroplasty (THA). This software has undergone a change in the operating platform to a Windows-based system that has also incorporated changes to DXA image manipulation on-screen. These changes may affect the magnitude of random error (precision) and systematic error (bias) when compared with measurements made using the previously validated DOS-based system. These factors could influence interpretation of longitudinal studies commenced using the DOS system and later completed using the Windows system. The aims of this study were to compare the precision and bias of pelvic and femoral periprosthetic BMD measurements made using the Windows versus the DOS analysis platform of the Hologic ‘metal-removal hip’ software. A total of 29 subjects (17 men and 12 women) with a mean age of 51years (SD±10), who had undergone hybrid THA using a cemented stem and uncemented cup. Subjects underwent duplicate DXA scans of the hemipelvis and proximal femur taken on the same day after a period for repositioning.. Scans were obtained with the patient lying supine in the scanner with the legs in extension and the foot in a neutral position. Scans were carried out using the same Hologic QDR 4500-A fan-beam densitometer in ‘metal-removal hip’ scanning mode. The DXA scan acquisitions were analysed using both the DOS and the Windows versions of the analysis software. The same observer made all analyses (NRS). Pelvic scans were analysed using a four region of interest model and femoral scans were analysed using a seven region of interest model. Precision was expressed as coefficient of variation (CV%) and compared between methods using the F-test. Systematic bias was examined using the Bland and Altman method and paired t-test. The CV% for the pelvic regions of interest (n=4) varied from 3.92 to 8.54 and from 2.36 to 5.96 for the Windows and DOS systems, respectively. The CV% for the net pelvic region was 3.04 and 2.36 for Windows versus DOS, respectively (F- test, p> 0.05). The CV% for the femoral regions of interest (n=7) varied from 1.58 to 4.14 and from 1.84 to 4.65 for the Windows and DOS systems, respectively. The CV% for the net femoral region was 1.75 and 1.51 for Windows versus DOS, respectively (F- test, p> 0.05). Absolute BMD values for the net pelvic region were similar (Bland-Altman, Windows minus DOS value mean = -1.0%, 95% CI −7.5 to 5.6; t-test p.0.05). Absolute BMD values for the net femoral region were also similar (Bland-Altman, Windows minus DOS value mean = 1.3%, 95% CI −8.3 to 10.8; t-test p.0.05). In summary precision of the measurements using the 2 operating systems was similar and there was no systematic bias between methods. These data suggest that scans analysed using each platform may be used interchangeably within the same study subjects, without the need of a calibration correction.
Methotrexate and Cox-2 inhibitors are thought to interfere with bone healing. There have been controversial results published in the literature. The effect of newer antirheumatoids (Leflunomide, Etanercept, Infliximab) has not been studied. The aim of this study was to find the in-vitro effect of methotrexate, newer anti-rheumatoids, steroids and cox-2 inhibitors on Osteoblasts. Osteoblasts were cultured from femoral heads obtained from young otherwise healthy patients undergoing total hip replacement. The cells were cultured using techniques that have been previously described. A computer aided design of experiment was used as a model for setting up the experiment on samples obtained from five patients. Normal therapeutic concentration of the various antirheumatoids was added alone and in combination to the media. The cell growth was estimated after two weeks using spectrophotometric technique using Roche Cell proliferation Kit. Multiple regression analysis was done to estimate the best predictor of the final result. Patient was found to be the most significant factor (p< 0.001) in predicting the ultimate response. Cox-2 inhibitor (Etoricoxib) was found to be the next best predictor (p=0.043). Etoricoxib in fact had a stimulatory effect (R=0.219) on the osteoblast growth, which was accentuated in the presence of other agents that varied amongst different patients. Different patients respond differently to the drugs. None of the antirheumatoids inhibit osteoblast proliferation and differentiation in-vitro. If osteoblastic activity is considered to be the primary factor responsible for bone healing, then an inhibition should not result in patients who are on these drugs.
The purpose of this study was to determine the effect of the use of a system to retransfuse salvaged drainage blood in patients undergoing primary THR with the aim of avoiding the significant risks that allogeneic blood transfusion poses to the patient. This was a retrospective cohort study where records of 109 patients undergoing elective THR following the introduction of an autologous retransfusion system at the institution were compared with a cohort of similar patients who underwent the same procedure prior to the introduction of the autologous system. The two groups were matched for age, surgeon, approach and technique and the results were subjected to statistical analysis. The use of a system to retransfuse postoperative salvage drainage blood, without concomitant use of predonation or intraoperative blood salvage, significantly reduced the need for allogeneic blood transfusion from 30% to 9%(p< 0.001). Patients who received salvaged blood also had a significantly smaller haemoglobin drop (Difference 0.56g/dL p=0.001) in the perioperative period, even though the preoperative haemoglobin level was not significantly different in the two cohorts. The overall cost of using the retransfusion system was similar to that of routine vacuum drainage when the savings of reduced allogeneic blood transfusion were considered. In conclusion the retransfusion of postoperative salvage drainage blood is a simple, effective and economical way of providing autologous blood for patients undergoing primary THR
Developments in motion analysis technology over the last two decades have enhanced our understanding of human locomotion. However, such advances in knowledge are futile if no practical use is made of them. Scientists and engineers need to make the most of these developments by forging stronger links with orthopaedic surgeons and applying further advances in their knowledge to clinical problems for the long-term benefit of patients. This need has been identified by many in the field of biomechanics and a “serious attempt [has been made] to take gait analysis out of the research laboratory and into the clinic” (Whittle, 1996 pp.58). For this reason, the aim of this research is to develop an objective and quantitative classification tool that uses motion analysis to aid orthopaedic surgeons and therapists in making clinical decisions. Practical applications of this tool would include joint degeneration monitoring; diagnostics; outcome prediction for surgical intervention; post-operative monitoring and functional analysis of joint prosthesis design. The classification tool (Jones, 2004), based around the Dempster-Shafer theory, is logical and visual; as the progression from obtaining clinically relevant measurements to making a decision can be clearly followed. The current study applies the tool to identify knee osteoarthritis (OA) and post-operative recovery following total knee replacement (TKR) surgery. Knee function data from 42 patients (22 OA and 20 normal (NL)) were collected during a clinical knee trial (Holt et al., 2000). Nine of the OA patients were followed at 3 stages following TKR surgery. Using the tool, a subject’s knee function data are transformed into a set of belief values: a level of belief that the subject has OA knee function, a level of belief that the subject has NL knee function and an associated level of uncertainty. These three belief values are then characterized in a way that enables the final classification of the subject, and the variables contributing to it, to be represented visually. Initial studies using this technique have provided encouraging results for accuracy, validity and clinical relevance (Jones, 2004). The tool was able to differentiate between the characteristics of NL and OA knee function with 98% accuracy. The belief values and simple visual output showed the variation in the extent to which patients had:
developed OA and; recovered after TKR surgery.
Furthermore, the visual output enabled straightforward comparison between subjects and indicated the variables that were most influential in the decision making process for comparison with clinical observations and quality of life scores. The tool is generic, and, as such, would be applicable to a wide range of pathological classification and predictive problems.
Polysaccharide (alginate and chitosan) capsules coated with a unique self-assembled semi-crystalline shell of calcium phosphate provide an enclosed biological system for the spatial and temporal delivery of human cells and bioactive factors. The aim of this study was to demonstrate plasmid DNA entrapment, delivery and transfection of adjacent cells inside capsules, embedded capsules and plated. Bacterial plasmid DNA and/or bone cells (SaOS) was added to solution of sodium alginate solution supplemented with phosphate ions and mixed thoroughly. Alginate droplets were fed through a syringe into a solution of chitosan supplemented with calcium ions. Guest capsules were inserted into soft, pliable host capsules soon after immersion in chitosan solution. Capsules were then immersed in 2mL DMEM 10% FCS in 6-well plastic plates for up to 7 days to enable transfection to occur. Encapsulated bone cells were stained with standard X-Gal to show transfected cells expressing beta-galactosidase. DNA delivery and transfection was demonstrated within capsules containing SaOS cells and plasmid, an admixture of SaOS bone cells and plasmid (51%) and from capsules containing DNA alone suspended in media over plated SaOS one cells. We also demonstrate capsule transfection of encapsulated cells in vivo. Transfection efficiency is highest when plasmid is entrapped and released from embedded capsules followed by plasmid/ SaOS admixture within capsules and lowest efficiency was observed with plated SaOS cells (with a transfection efficiency of 5%). The ability to regulate shell decomposition by manipulating the degree of mineralization and the strength of gelling, and release of capsule contents provides a mechanism for programmed release of gene modulated cells into the biological environment. The beta-galactosidase plasmid was found to be strongly associated with the chitosan/ calcium phosphate shell as shown by ethidium-homodimer-1 staining of encapsulated DNA and this may assist the transfer from gel to cell. Programmed non-viral delivery of genes using biomaterial constructs is an important approach to gene therapy and orchestrated tissue regeneration. These unique biomineralised polysaccharide capsules provide a facile technique, and an enclosed biomimetic micro-environments with specifiable degradation characteristics, for the safe encapsulation and delivery of functional quantities of plasmid DNA with the implicit therapeutic implications therein.
The aim of this study was to assess the usefulness of Cast index and an indigenously developed Gap index as measures of poor moulding of plaster. 20 cases of re-manipulation of distal third forearm fractures excluding growth plate injuries were compared with a control of 80 patients. 5 patients in the control group had an axial deviation of more than 10 degrees but were not remanipulated and therefore were included in the failure group. The gap index and the cast index of the two groups was compared as predictors of failure of conservative treatment. The groups were similar in terms of demography and post reduction alignment. There was a significant difference (< 0.001) in the Cast index and the Gap index of both the groups. The sensitivity of the Cast index (> 0.8) in predicting failure of plaster was 48% while that of the sum of Gap index (> 0.15) in AP & Lat view was 88%. Gap index was found to be more accurate (84%) than Cast index (78%) in predicting failure. The gap index is a better predictor of failure than the cast index. A quick assessment of these indices, especially by the less experienced surgeons, is a good practice before accepting any plaster following a manipulation of distal radial fractures. It would not only save the patient a second anaesthesia but also complications of a more extensive second procedure and of course hospital resources.
Injury to the core region of energy-storing tendons is a frequent occurrence in both human and equine athletes, the incidence of which increases with age. Such energy-storing tendons include the human Achilles tendon (AT) and the equine superficial digital flexor tendon (SDFT). By definition, energy-storing tendons experience high strains during high-speed athletic activity. In contrast, anatomically opposing tendons (“positional” tendons), such as the common digital extensor tendon (CDET) in the horse and extensor digitorum longus tendon in man act only to transmit muscular force and rarely suffer exercise–induced injury. Functional adaptation of muscle and bone in response to exercise is well – documented, but there has been no convincing evidence to suggest that the energy-storing tendons in adults have the ability to adapt to exercise. We hypothesised that adaptive increases in tenocyte cellularity would occur in the energy-storing and positional tendons of young horses subjected to three specific exercise regimens. Samples were taken from midmeta-carpal regions of the SDFT (periphery and core) and CDET of young Thoroughbred horses from the following groups. Group 1: 6 horses exercised on a high-speed treadmill for 18 months from 21.3 months of age (SD 1.1) with 6 age-matched controls that underwent walking exercise only (long-term); Group 2: 6 horses exercised on a high-speed treadmill for 18 weeks from 19.4 months of age (SD 0.6) with 6 age-matched controls that underwent walking exercise only (short-term) and Group 3: 6 horses trained on pasture in New Zealand for 18 months beginning at 7–10 days of age, with 6 age-matched controls kept at pasture with no additional enforced exercise (Global Equine Research Alliance). Tenocyte nuclei were counted and measured in digital images from histological sections stained with haematoxylin and eosin, by computerised image analysis. Tenocyte densities (per mm2) for exercised and control groups for each study were evaluated using paired t-tests. Tenocyte density was significantly higher in the CDET of exercised horses in Group 3 (mean ± SD =260.4 ± 23.4) compared with the non – exercised controls (mean ± SD =226.9 ± 23.8) (p < 0.01). There was no such difference in the SDFT (core or periphery). There was also no significant exercise-related difference in tenocyte density in either the SDFT (core or periphery) or CDET for Groups 1 or 2. No previous data is available on the effect of exercise on tenocyte populations in equine tendons. The lack of other adaptive changes in previous studies of mature equine tendons had raised the question as to whether immature tendons would be more able to adapt to mechanical stimuli. In this study we were able to show that beginning training of horses shortly after birth (Group 3) stimulated an adaptive response by tenocytes in the positional CDET but not the SDFT. The inability of energy-storing tendons to show functional adaptation to exercise in immature or mature animals may explain the high incidence of strain-induced injury. Understanding the pathway by which exercise-related increases in tenocyte densities occur in immature positional but not energy-storing tendons may increase our understanding of the pathogenesis of strain-induced tendon injury.
The Authors report their experience in the treatment of scaphoid non-union recurring to the vascularised bone graft technique as described by Zeidemberg. The patients have been treated between the 1999 and 2004. The authors report 22 cases (21 males and 1 female) with an average age of 31 years (from 17 to 42). 10 cases the involved wrist was the right one and in the other 12 cases was the left one.
18 patients presented an avascular necrosis of the proximal fragment of the scaphoid, recognised by the MNR. Two patients have been previously treated by the traditional bone graft technique as described by Matti-Russe, using a cannulated screw for the stabilization of the graft. 16 patients have been controlled at the follow-up (mean 23 months, from 3 to 65). The authors, looking at the good results obtained at the follow-up, feel that this technique might be a very useful one in the treatment of the established scaphoid non-union, mainly in presence of an avascular necrosis of the proximal third of the scaphoid. This technique might also be useful in the treatment of the failure of the classic bone graft technique.
The Authors report a case about a scaphoid remowing’s wrong operation performed in anohter hospital on a woman who was affected by rizoarthrosis. The authors visited the woman in the clinical outpatients six months after the wrong operation. In the Centre of Hand Surgery and Microsurgery of Modena the Authors performed an operation of an arthrodesis of TM associated with a arthrodesis capitate-lunate-hamate on that woman. The Authors report the good clinical outcome and X-ray’s results.
Forty patients with subcutaneous rupture of the Achilles tendon were enrolled in a prospective study and randomised to two groups: group A treated with open surgery with Kessler-type suture, and group B treated by percutaneous tenorraphy (Tenolig®) under ultrasound control. The follow-up included an objective and a subjective (SF-12) clinical evaluation at 4, 12 and 24 months, ultrasonography at the same time points, and isokinetic muscle performance tests at 12 months. There were no significant differences between the two groups at clinical and ultrasound evaluation except for a greater ankle circumference in group B (p< 0.01) at 12 months; peak torque and total work isokinetic tests did not differ significantly in the two groups nor between involved and uninvolved side. At 24 months data show similar clinical and ultrasonographic results with both techniques, leading us to prefer percutaneus tenorraphy under ultrasound control owing to the attendant advantages of local anaesthesia in day surgery, decreased risk of skin complications, reduced surgical time, faster functional recovery, and greater patient compliance.
The significance of flat-foot in childhood and adolescence in Italy has never been studied on a statistically significant sample.
In our survey, thousands of subjects from different regions of northern, central and southern Italy (Calabria, Lazio, Umbria, Lombardia) were studied in order to determine the prevalence of flat-foot and search for possible genetic or environmental factors that may influence the normal development of the longitudinal arch, starting from birth.
Podoscopy was integrated with anamnesis, physical examination and measurement of weight and height. Footprint morphology has been related with variables such as age, sex, geographical area of origin and BMI (Body Mass Index).
The anatomical integrity of the epi- and para-nevrium is the most relevant factor for the correct gliding of the median nerve, and when they are surrounded by scar tissue, the result is a chronic neuropathy. This recurrent compressive neuropathy represents a very challenging clinical and surgical problem. Neurolysis can not always improve the recovery of nerve function, and the soft tissue coverage is necessary to prevent recurrent scar and to achieve a useful mobilization of the median nerve. The autogenous vein graft wrapping technique has shown great promise for the treatment of chronic compressive neuropathy after other procedures have failed. The author present their experience using the Basilic vein grafting as a valid alternative to the Saphenous one. All our patients presented symptoms in the median nerve distribution, including pain, swelling and numbness, and grip strength reduction. Four of these patients presented a CRPS and have been evaluated before treatment in a multidisciplinary dedicated equipe to plan the surgical procedure. The vein graft wrapping represents a simple technique without problem in donor area. In the authors’ casuistry it presented also as a very useful technique in the treatment of median neuropathy in CRPS.
The main problem, in the follow up results is a lack of pronosupination that stresses the importance of a perfect reduction of distal radioulnar joint to begin early a phisiotherapy
We believe that a combination of the two fixation system allow an optimal external stabilization in the first week (So the therapist can move the patients in intensive care room). Secondary the internal fixator allows an anatomical reduction with a stable fixation in the secondary kinesiterapeutic time.
Dislocation and carpal fracture-dislocation are a rare injury, interesting capsula and ligaments, with a variable damage of the vascularization. Classification is difficult for the complexity on this lesion.
The aim of our work is to underline how the best final clinical result is achieved after an immediate treatment of reduction and stabilization of bone injury.
We considered two groups:
A: 13 patients, who have been observed since 1991 until 1998:
B: Another group is at short term is since July 2002 until 2005 and is in 20 patients with 21 wrists 1 is bilateral.
Finally we think that is necessary, to avoid the instability and pseudoartrosis on the scaphoid, to treat all the transcapholunate dislocation with open reduction and stabilisation, as agreed with literature.
The aim of the study was review all the type B and Type C according with A.O. classification tibial plateau fractures from January 1995 to August 2004 with a minimum follow up of six months. It has been selected all the patients treated with closed surgery. In the treatment of type B fractures we used cannulated screws, sometimes with external fixator. In the treatment of type C fractures we used external fixator. As a result of the technical improvements, in the recent years, external fixation has become a surgical technique not only for the treatment of open fractures but also for the management of comminuted fractures with percutaneous synthesis, since there is no need to open the fracture site. In our recently experience we have used a hybrid fixator which is single-use, pre-assembled and radiolucent.
The authors report their results of “extension-block Kirschner wire fixation” for the treatment of mallet finger fracture. This technique should be considered in presence of a large bone fragment involving more than the 30% of the articular surface, with or without palmar subluxation of the distal phalanx. A modification of the extension-block technique is described reducing the fragment to 0° extension of the distal interphalangeal joint. The results confirmed the better outcomes of this modification, minimizing the postoperative extension lag at the distal interphalangeal joint. The Wehbe and Schneider method was used to classify the mallet finger fractures and the results were graded according to Crawford’s criteria (66,6% excellent and 33,4% good). The extension-block K wire technique, when properly applied, is a very helpful procedure avoiding the risks and complications of the open surgery and achieving a good indirect anatomical reduction of the fracture.
The aim of the study was to test the biomechanical effectiveness of the radiolucent fixator “X-caliber”. For this reason, care was taken to include a heterogeneous group of leg fractures capable of treatment with external fixation. A multi-centre study was organized to taste the biomechanical effectiveness of the radiolucent synthesis device. Our centre was equipped with this external fix-ator, which is preassembled and completely radiolucent.
The fixator is manufactured from a carbon fibre composite, with stainless steel cams and locking nuts, and aluminium alloy bushes.
The fixator types comprise standard fixators, fixators with a periarticular ring attachment, and fixators with a swivel clamp for ankles. Between December 2000 and May 2002 the authors tasted the biomechanical effectiveness of the new fixators in 13 patients with leg fractures. After a follow up of 6 months, analysing the results of other centres the authors retook the utilization of the radiolucent fixator and, in this paper, relate their total experience until April 2004 in 42 patients with leg fractures.
Lateral unstable fractures of the femoral neck represent a controversial problem for the surgical treatment, due to the difficulty in achieving an adequate mechanically stable bone-devices system. Compression hip screw alone has proven to be inadequate, while in association with the trochanteric stabilizing plate (TSP) it offers better results. The authors analyse functional results and complications of a series of 87 lateral unstable fractures of the femoral neck (type A2 and A3 of the AO classification). Weight bearing was allowed 48 hours after surgery. The most important complications reported were: persistent trochanteric pain (12 cases) shaft medialization and device mobilization (2 cases) shortening of more than 2cm (3 cases). All complications were reported in A3 type fractures. Our data confirm the efficacy of the TSP the treatment of lateral unstable fractures of the femoral neck (type A2) because it stabilizes the lateral cortex. In A3 type fractures, intramedullary devices offers better results than compression hip screw and TSP in terms of complications rate and stability.
Fractures of the distal metaphysis of the tibia represent 7–10% of tibial fractures and less than 1% of the lower limb fractures.
Their treatment is difficult and presents a high percentage of bad results because of comminution of the metaphyseal bone fragments, articular involvement, poor circulation in the distal third of the leg. Until few years ago, in presence of a comminuted fracture, the only surgical possibility was the use of plate and screws. The external fixation represented a temporaneous treatment in case of open fracture or severe soft tissue damage. The recent technology applicated to external fixation has transformed the external fixator in synthesis device less uncomfortable, to increase the compliance of the patient, and more stable, to be used in the definitive treatment of this fractures. Recently we change the external fixator with double ring in a monolateral external fixator with single ring, in the “hybrid frame”.
Reduction and fixation with a paracortical sliding screw or an intramedullary nail are the most used treatments for intertrochenteric fractures.
In cases of complications the attempt to perform further internal fixation may lead to failure because of the poor quality of bone and cartilage. Conversion to a hip replacement seems a better choice and the use of long stems with a distal, diaphyseal fit appears to be a good option, allowing to by-pass the intertrochanteric region. Authors report their experience in hip replacement for failed treatment of hip fractures that allow to restore immediately the function of the hip.
This paper describes our experience about isthmic reconstruction on younger children.
The so called “floating knee” is the result of ipsilateral fractures of femur and tibia.
The definition of floating knee dates back to 1974, when Blake and Mc Bryde proposed it in order to move the attention from the skeletal plane of the lower limb to the articular and vasculonervous plane of the knee, where complications are more frequent and dreadful: lesions of popliteal artery or sciatic nerve, stiffness or instability of the knee.
The timing of surgical treatment is still debated: in fact it may be immediate but provisional, with necessity of a second operation, or delayed but definitive.
Also the strategy of osteosynthesis may be controversial, because of the association of fractures.
We present a series of 3 cases (among them there were also 2 ipsilateral fractures of patella) with both femur and tibia treated by osteosynthesis with plate (1 case, with complications) or nail (2 cases, without complications): the patients were followed-up clinically and with X-rays for 1 year.
Our experience confirms the gold standard for this kind of fractures is locked intramedullary nailing, retrograde for femur and antegrade for tibia.
The authors evidences the results of their experience, matured in the Orthopaedic and Traumatologic Division, of Fano Hospital, that have been involved 106 patients with lateral femoral fractures from the January 2003 to 31st July 2004, treated with endomedullary nailing (Endovis). With a medium follow up of 12 months, 89 patients have been estimated clinically and radiologically, classified second to AO-Muller: 31A1 (21%), 31A2 (46%), 31A3 (33%).For all the patients we have used the classification of operative risk ASA: ASA 1–2 (88.5%), ASA 3–4 (14%), ASA 4 (2.5%).In agreement with the literature, the 88%, of the patients have been subordinate to surgical intervention within 48 hours, from the admission, while for serious patients with severe pathology, the treatment has been done within the 72 hours. In only 3 patients (1%) the surgical intervention was complicated with break down of the screw; in 8 cases (7.5%) an iper-correction in valgus position.
As the importance from socioeconomic point of such pathology, we think that the Endovis nail, is a valid method of osteosynthesis and it guarantees an early mobilization, reduced hospitalisations with obvious positive reply on the cost/benefit ratio.
From January 2003 to December 2004, 160 consecutive intertrochanteric hip fractures has been treated at the Orthopaedic Rizzoli Institute by a new short intra-medullary rod, which can be distally locked, combined with two sliding screws that insert into the femoral neck and head. The rod is an undersized, titan one. It can be inserted percutaneously.
Fractures were classified pre-operatively according to stability and post-operatively according to the type of operative reduction.
The failure rate and post-operative stability were then compared according to the type of fracture and to the quality of operative reduction.
Results indicate that the pre-operative fracture classification is a significant determinant of post-operative stability. The type of operative reduction was not as significant a determinant of post-operative stability, but an anatomical reduction gives better clinical results.
Overall results shows that stable fractures has always healed and only minor complications has been observed. Unstable fractures has a percentage of drawbacks of 1.5% (3 in 160 pts) due to a wrong screw positioning ( 2 proximal and 1 distal ).
Three patients died in the early post-operative period due to cardiac failure.
No intraoperative fracture, no displacement of the fracture site and no “cut out” were observed.
Mesenchymal stem cells (MSCs) are exciting candidates for cellular repopulation and repair in intervertebral disc degeneration (IDD). Our purpose is to investigate the interaction between MSCs and nucleus polposus cells (NPCs) and to determine viability of MSC in the intervertebral disc (IVD).
Human NPCs and hMSCs were co-cultured in pellet system at different ratios. Proteoglycans were measured and normalized with DNA content. Histological analysis were also performed. Rabbit MSCs from bone marrow were trasduced with LacZ reporter gene and were injected into a rabbit IVD. Rabbits were sacrificed postoperatively at 3, 6, 12 and 24 weeks. Histological analysis was performed.
Co-culturing of hNPCs with hMSCs resulted in increases proteoglycans as compared with hNPCs alone. Histological examination of the injected IVDs revealed presence of MSCs without apparent decrease in numbers or diminishment of protein production at 3, 6, 12 and 24 weeks.
The data from this study show that there is a synergistic effect between MSCs and NPCs resulting in upregulated proteoglycan synthesis in-vitro. MSC remain viable and continue to express an ex-vivo transduced protein for up to 24 weeks. These results suggest that MSCs can survive in the harsh environment of the IVD and may favourably modify ECM production.
The aim of this study was to analyse the morphological differences of the intervertebral disc at different levels focusing in the endplate and the anchorage of the disc fibres to the vertebrae and the distribution pattern of collagen I and II.
This study was conducted on 45 intervertebral discs from nine monkeys (Macaca fascicularis). All slices were processed for histological, histomorphometrical and immunohistochemical analysis.
The endplate was formed, at all the levels, by 3 zones: a cartilaginous zone adjacent to the nucleus pulposus, an intermediate mineralised zone of cartilage and a growth cartilaginous zone adjacent to the vertebrae.
The inner annular fibres anchored to the not mineralised cartilaginous endplate zone, whereas the outer annular fibres anchored to the mineralised cartilaginous endplate zone.
The height of the intervertebral disc varied along the length of the spine. The smallest value was measured in T3–T4, with a larger increasing caudally than cranially. The highest value was measured in L2–L3. A cervical intervertebral disc was the 55% of a lumbar one.
The findings of this study provide a detailed structural characterization of the IVD and may be useful for further investigations on the disc degeneration process.
The main problem in revision hip surgery is the loss of bone, expression of the reactive phenomena to the granulation tissues secondary to debris production. The choice of surgical system and strategy is related to the bony loss.
The tantalum, due to its elevated porosity and microarchitecture and elasticities similar to trabecular bone, facilitates the periprosthetic osteointegration, so to be considered particularly indicated in acetabular revisions.
The Authors present clinical and radiological results of a two years experience with tantalum hemispheric cup, emphasizing its versatily, with possible choice between a model with reinforce net-like function with a cemented polyethylenic component and other with standard modular inlay.
In case of serious bone-loss bone banking graft has been used (except in septic mobilization, although a two-stage proedure with the use of temporary antibiotic-impregnated spacer) and two or more screws for additional fixator.
B and C vertebral fractures types sec. Magherl have univocal indication to the surgery even if are in discussion both type and number of approaches than the characteristics of the osteosynthesis. About A type, instead, is debated if the treatment must be conservative or surgical. With the acquired experience in vertebro/kyphoplasty for the treatment of metastatic osteolytic or ostheoporotic fractures, Verlaan et al, in 2002, emphasized the possibility to use the kyphoplasty, in association to posterior stabilization, for treatment of traumatic toraco-lumbar A1-A2-A3 fractures, in order to reinforce the front column and to increase the vertebral body resistance. This idea, the experience of the kyphoplasty, the sophisticated B-Twin Expandable Spinal System mechanism, initially studied like intersomatic cage, are the base of a our technique for the treatment of great part of A type vertebral fractures.
The expansion of B-twin, introduced with transpe-duncolar approach, raise the plate reducing the fracture and creating an intraspongy space in which is possible to inject the cement at low pressure. We apply this technique approximately from one year, even if still experimental, without any cement complications or vertebral late sinking evidenced although we have always authorized the premature and not protected walking.
Different revision stems are described in literature: from the primary systems, with or without cementation, used for minor defects of the proximal femoral region, to special revision stems employs in order to by-pass meta-epiphyseal zones with high loss of bone-stock and to search a distal fit.
The Authors describe their experience with modular system ZMR (Zimmer, Warsaw, IN, USA), in Titanium alloy, available in two “configurations”: porous, in three distinct porous body styles with variable inclination neck to pair with straight or porous bowed spline stems available in different lengths and diameters optimising axial and rotational stability, and Taper, designed to provide a better distal fixation transmitting axial, torsional and bending loads to the adjacent bone through a splined taper stem, a more physiological cervical-diaphyseal angle and a neck planned in order to save the calcar zone. The mid-stem junction uses a Morse-type taper connection with a dynamometric system to assure locking of the body and stem components.. The Authors underline the benefit to use a versatile system able to allow the intraoperatory choice of antiversion, diameter and length more adapted diminishing the risks of a post-operative sinking and avoiding the corrosion phenomena of splice sites.
Published experimental data on BMP-7(OP-1), carried by collagen type 1 (Osigraft), related to reconstructive surgery attest that: it accelerates and improves the incorporation of strut allograft; the combination of OP-1 with auto or allograft results in an improvement of critical size defect healing from radiological, histological and mechanical perspective.
In human revision hip surgery, OP-1 has been used with morcellized allograft, proximal femoral allograft and bulk femoral head allograft for acetabular or femoral reconstruction: a faster and more evident new bone formation as well as a faster incorporation of grafts has been shown compared to what expected without OP-1 usage.
Even if OP-1 usage in hip surgery is not approved by regulatory agencies, because of lack of randomised clinical studies, we decided to use it in patients with serious acetabular defects (II/III GIR).
In our experience, we treated eight patients with OP1, in conjunction with allografts. Clinical, radiographic and densitometric analysis has been done at 3, 6 and 12 months.
Preliminary densitometric results show that the quantity and features of new formed bone are superimposable to natural bone.
80% of myeloma patients have lytic bone lesions and osteoporosis secondary to corticosteroid therapy with high rate of vertebral compression fractures (VCFs). The consequences include pain and spinal deformity. The treatment ideally should address both the fracture-related pain and associated spinal deformity. Kyphoplasty provides a new tool that may impact bone care entailing the insertion and expansion of an inflatable bone tamps (IBT) in a fractured vertebral body. Bone cement is then deposited into the cavity to correct the deformity and improvement in structural integrity of collapsed vertebra.
Eighteen VCFs were treated during 11 balloon kyphoplasty procedures in 7 multiple myeloma patients. The clinical outcomes were assessed according to visual analogue scale with 0 representing no pain and 10 severe pain. Patients rated their pain before surgery, 1 week after surgery and at 1 year-postoperative period.
Mean improvement in local sagittal alignment was 12.3°. All of the patients who had reached the 1-year postoperative period had reported a high reduction in pain.
Treatment with chemotherapy and/or radiation therapy is very important in the control of bone disease. Patients treated with kyphoplasty in combination with pharmacologic therapy return to higher activity levels, leading to increased independence and quality of life.
The problem of modular acetabular cups in total hip replacement (THR) links with its survival, unpredictable because of wear and fixation. In fact, while primary fixation is not a problem, the use of screws could generate bone resorption. A monoblock cup made by tantalum and polyethylene insert is available since some years. Tantalum is a metal element with an elasticity intermediate between cortical and trabecular bone, a three times higher porosity than titanium and a very high ductility. These features allow a very high primary and secondary stability eliminating movements between insert and metal.
From 2001 we started using the TMT cup and we performed 48 implants in 45 patients: 18 male and 30 female. The mean age was 64 years old.. 80% of the patients were affected of primary arthritis, 20% avascular head necrosis and fracture. In last 20 procedures we perform a minimal invasive approach (around 9 cm.). The mean follow up was 26 months. We reported no infections, no loosening and 1 traumatic dislocation. Follow up showed good stability on the acetabular side.
In conclusion we can affirm that, despite our preliminary results, the tantalum cup could open new perspectives in primary hip replacements.
Renal neoplasm is the most frequent cause of metastases, after prostatic and breast carcinoma.
Lesions are aggressive and expansive with cortical destruction and soft tissue extension. Pathological fracture is very common, up to 50%. The most frequent localizations are long bones, spine and pelvis.
Aim of this work is to evaluate the usefulness of surgical treatment of soft tissue and skeletal metastases in kidney neoplasm.
Between 1995 and 2005 66 patients (40 males, 26 females) were submitted to surgical treatment at San Raffaele Hospital, Milano. Most common localizations were femur, humerus, spine, pelvis, metatarsus. We report 3 cases of soft tissue metastases of lower limb.
Twenty-five patients had single localization, 10 pathological fracture and in 5 diagnose was bioptical.
Surgical treatment was performed with large resection and in 15 patients the lesion was embolized.
Twelve patients had local relapse and in 3 we performed a new surgical treatment.
We had no infections nor fatal outcome in the post-surgical period.
It is well known that wide resection and reconstruction with modular or composite prostheses is the treatment of choice in high chondrosarcoma of metasepiphyseal bone. Nevertheless there is a debate concerning the treatment of low grade chondrosarcoma, a locally aggressive tumour, similar also histologically to benign lesion. Two different therapeutic options are reported in these lesions: wide resection and intralesion curettage. Between 1995 and 2003 the Authors analysed a series of 37 cases of low grade chondrosarcoma of long bone treated with curettage and local adjuvant, like liquid nitrogen and acrylic cement, if necessary associated with synthesis. The least follow-up was two years. The authors observed 3 local recurrences within the first 12 months from the surgical treatment; and, in every case, an increased grade of malignity was observed at histology. The Authors confirmed that the aggressive intralesional treatment with the use of the local adjuvant like liquid nitrogen and cement, is a valid therapeutic possibility in these lesions, but they confirm that it’s necessary an accurate preoperative diagnosis with also open biopsy for an efficacy treatment.
Biomaterial porosity is considered one of most important proprieties required to obtain fixation of bone ingrowth and ongrowth in prostheses.
Since 1998 in the USA and from in Europe a new highly porous biomaterial, Trabecular Metal Technology (TMT, ©Zimmer, USA) has been used in orthopaedic surgery.
This study evaluates the short-term morphological findings of porous tantalum screws implanted in three patients with osteonecrosis of a femoral head. Tantalum trabecular metal offers several advantages over conventional materials. Its regular porosity is considered one of most important properties in bone ingrowth and ongrowth and high biocompatibility and osteoconductivity. The biomechanical properties of tantalum are sufficient to withstand physiological load.
Our study disclosed a good integration. The bone penetrated the porous metal completely and many characteristics of good bio-integration were evident such as new formation of lamellae, presence of calcium and phosphorus elements, absence of fracture and signs of implant metallosis. The presence of peri-implant medullary cisternae confirmed the functional sites of new bone formation.
We conclude that the porous tantalum material is an optimal osteoinductor and osteoconductor even in critical conditions.
The aim of this study is to evaluate the efficacy of the use of the dynamic hip orthosis in subjects who are affected with degenerative hip diseases, even those who are waiting for a total hip replacement, and in subjects who had undergone a hip replacement because of a proximal femur fracture. For each patient we’ve prepared a card in which we’ve reported personal data, comorbidities, pharmacological and rehabilitative treatments, VAS, WOMAC, Barthel Index, GDS and a evaluation of the compliance. We’ve evaluated those patients periodically. Until now, and considering the follow up is not ended, we can say that the dynamic hip orthosis can be addressed to patients with mild to moderate hip osteoarthritis and in elderly who’ve been undergone surgery for a proximal femur fracture because it reduces pain, it facilitates a safer gait and it accelerates the functional recovery. However it is important the dynamic hip orthosis to become a part of an individualized rehabilitative project.
Elastofibroma dorsi is a rare benign unencapsulated tumour characterized by a elastic fibres proliferation in a collagen stroma with adipose tissue. Lesion is often asymptomatic, monolateral and localized at the tip of the scapular. It is slow-growing. It mainly occurs in adult females. At now some controversies concerning diagnosis and modality of treatment are reported in the literature. Authors report clinicopathological features of elastofibroma dorsi analysing 8 cases from 2001 to 2005, and revise the literature. Seven females and 1 adult male were observed, often dedicated to manual labour. Six symptomatic patients underwent marginal excision of tumour, and the remaining asymptomatic 2 patients were only followed. No local recurrences were observed in operated patients.
On the basis of these data Authors evidenced limits of different instrumental methodologies of diagnosis (ultasonography, computer tomography and magnetic resonance imaging) and suggested a algorithm for diagnosis and treatment remarking that marginal excision constitutes effective treatment of symptomatic patients.
The Hipstar cementless system (Stryker) is a straight, wedge-shaped with a rectangular cross-section, titaniumalloy (TMZF) femoral component. This particular titaniumalloy (titanium, molybdeno, zirconium and iron) makes the stem 20% more resistant and less elastic than TiAlV alloy. The advantages are: a thinner neck with an equal resistant, an increase of range of motion, a reduction of impingement.
We examined 100 consecutive primary THRs between January 2002 and March 2004. The mean age was 69,9. Preoperative evaluation included a physical and radiographic examination. The acetabular component was the Trident cup (Stryker). Clinically, all the 100 hips were evaluated according to the scoring system of Harris. A patient’s evaluation test (WOMAC test) was also performed. At the time of the latest follow-up, standardized antero-posterior and axial radiographs of the pelvis and hip were made and evaluated according to Engh radiographic score. The median duration of follow-up was 24 months.
The median post-operative Harris Hip Score for 100 hips was 90.5. The observed mean value of WOMAC test score was 5,11. At the time of the latest follow-up, there was a bony incorporation of all components. We have had 2 cases of dislocation. At the latest follow-up no evidences of infection are present.
Ceramics are used in hip prostheses in approximately 40% of the implants (ce/ce and ce/pe). The increase of the diameters (32 and 36 mm) in order to improve the stability and the Range of Motion of the prostheses is now the topic. Research and development has allowed creating new alumina inserts with smaller out diameter (39 mm for the 32 mm bearing and of 44 mm for the 36 mm ones). The new alumina matrix composite has allowed the realization of ceramic revision ball-heads. This system, made of 28 or 32 mm ball-heads with a titanium slivers (12714 internal cone), will allow applications of the ceramic ball-head on an in situ damaged taper. Beyond S, M and L lengths, will be available also an XL version. A femoral knee component, still in phase of study, has shown advanced resistances of 5, 8 and 15 times the body-weight in different load configurations. Have been carry out some tests in order to estimate the adhesion between the ceramic and the cement of different thickness and have been caught up values of 6,17 MPa (2 mm) and 14,90 MPa (0,7mm).
Dysplasia epiphysealis hemimelica is a rare congenital abnormality of enchondral ossification of one or more epiphyses, thus determining an asymmetrical growth in that bone district. We are here considering 2 cases. The first case regards a 4-month-old female baby with an irreducible flexion of the right knee. The X-rays highlighted an area of different density with irregular contours and multiple ossifications; the MRI showed a bone lesion with osteocartilaginous structure in contiguity with the medial condyle; during the operation a osteocartilaginous formation partially fused with the medial condyle was observed. The second case regards a 10-month-old male baby, with a medial malleolus swelling. The X-ray highlighted an area of different density with irregular contours and multiple ossifications, medial to the epiphyseal nucleus of the talus; the MRI showed an osteocartilaginous lesion in contiguity with the talus; during the operation an osteo-cartilaginous formation fused with the talus was observed. The histological findings confirmed in both cases the presence of cartilaginous and bone tissue in absence of pathological lesions.
Being a lesion of malformative origin, the early removal of the abnormal ossification nuclei will permit to avoid the secondary lesions described in literature, like asymmetrical growth of the limb and functional limitation.
Aim of the study was to evaluate the recovery and short term results of simultaneous bilateral unicompartmental knee replacement in front of unilateral procedure.
Fractures of lower limb treated with Open Reduction and Internal Fixation (O.R.I.F.) are frequently complicated in the postoperative period. Minimal Invasive Plate Osteosynthesis (MIPO) is developing for subcutaneous plating. The purpose of this study is to demonstrate the improvement in dropping the risks of complications following internal fixation using MIPO. From January 1998 to May 1999 we collected 32 cases of lower limb fractures treated with O.R.I.F (Group I). From June 1999 we started to perform MIPO in closed fractures of lower limb with conventional and new devices with angular stability that offer more mechanical stability (Group II 90 cases). In Group I we got 2 infections in pilon fractures, 3 delayed union in distal tibial fractures, 1 non-union in distal femoral fracture, 1 varus deformity in distal femoral fracture and 2 DVT. In Group II we had only 4 cases of varus deformity and 1 DVT.
The findings of this study justify the effort to follow this procedure also because the new devices available improved mechanical stability. MIPO is a demanding technique with undoubted advantages: it respects the biology of callus and soft tissues, it reduces the necessity of bone graft and is particularly indicated in polytrauma patients.
Patients were evaluated clinically and instrumentally before the first application and at one and three months of follow-up. Three disability scales we utilized (NRS, Mcgill Pain Questionnaire e Chronic Pain Grade Questionnaire).
Obesity is strongly linked to osteoarthritis; can affect the outcome of total knee arthroplasty and can increase the load on the components with reduction of the implant’s survivorship.
The purpose of this study is to compare clinical and radiographic outcomes in obese (defined as BMI > 30) and non obese patients.
The Knee Society scoring system and WOMAC was used to evaluate the knees preoperately and at latest follow up.
With a follow up ranging from 1 to 5 years, Knee Society score and WOMAC for the patients who were obese were lower than non obese patients.
Non progressive radiolucent lines were located adjacent to the tibial component in the group of obese patients, but without clinical significance.
Poor results increase in older patients. After Orthopaedic treatment 60% of hips in children with LPC Disease appearing before the age of 6 find again its sphericity (Stulberg 1 or 2). About 30 % of hips in children with LCP Disease appearing between 6 and 9 years of age became “normal” (Stulberg 1 or 2) at the end of growth/Only 1 hip out of 10, in the oldest group of children (over 9 years), became spherical at the end of growth. Surgery increases the percentage of good results in all groups of patients.
Fracture of the Tibia in children usually are treated conservatively. Isoelastic intramendullary nails is an excellent method in order to fix the instable fracture of the shaft of the tibia. The method has a low rate of complications and combines the advantages of the closed reduction and internal fixation technique with the conservative method. The technique allows a precocious weight bearing.
Our retrospective study consider the clinical and radiological outcome of the tibia fractures fixed with intramedullary nails by Metaizeau.
From January 2000 till June 2004 over 150 tibia fracture were observed in our Institution.
14 instable shaft tibia fracture were treated with intramedullary nails. Medium follow up is 33.6 months. Mean Age 11.7 years.
All fractures healed in a mean time of 11 weeks.
No infection, no damage of the physis or refracture were observed.
Metaizeau nails give an elastic but in the same time a stable fixation. This point is very important especially when we have to treat a patient with associated lesions.
The technique has a low rate of infections and recurrence.
A knee functional spacer made of antibiotic-loaded acrylic cement was used for treatment of infected TKA with two-stage exchange arthroplasty procedure.
The Spacer K is a preformed articulated spacer with the characteristics of an ultra-congruent condylar knee-prosthesis, made of acrylic cement impregnated with antibiotic (gentamicin). The device, industrially pre-formed in 3 sizes (Spacer K, Tecres), with standardised mechanical and pharmacological performances, was implanted in 21 consecutive patients all affected by late (8) infection according Segawa classification. Infection was caused by CoNs (16 cases), MSSA (1), Micrococcus spp (1), Enterococcus spp. (1). In 2 cases the germ was not detected. All knees presented the integrity of extensor apparatus and of peripheral ligaments (medial), furthermore type I & II bone loss according to Engh’s classification. Mean implantation time was 12 wks. Post-op following std. rehabilitation program as with primary TKR. We evaluated: healing of infection (clinical parameters, CPR, ESR, biopsy); clinical results and functional outcome (KSS); mechanical device behaviour (breakage, wear: macro – and microscopic surface evaluation, histological examination of peri-prosthetic tissues); possible related complications (bone loss, instability or dislocation, loosening: intra- and postoperative evaluation, x-ray study). The results obtained shows that the spacer K is effective and safe.
In the past the prevailing view believed that there was an inverse relationship between osteoarthritis and osteoporosis; a recent study showed that elderly women with advanced osteoarthritis requiring total hip replacement had an evidence of osteoporosis and vitamin-D deficiency. An altered metabolic bone status as induced by low level of vitamin D could be one of the major causes of aseptic bone loosening and consequently failure of the implant. We studied the bone mineral metabolism of thirty elderly women with osteoarthritis undergoing total hip replacement in order to identify whether or not there were a bone metabolic alterations.
All the subjects included in the study were over than 70 years old (mean age 74 ± 2.5). The results showed that six (20%) subjects had a hypovitaminosis D status and eighteen (60%) had a vitamin D deficiency status. Five subjects (16%) had a secondary iperparathyroidism. The bone mineral metabolism of elderly women with osteoarthritis undergoing total hip replacement is characterised by a high prevalence of vitamin D deficiency and in a less percentage of the cases by a secondary iperparathyroidism. Both of these metabolic conditions could compromise the bone integration of the implant and lead to aseptic bone loosening.
The study describes the changes of condrocytes and extracellular matrix occurring in Hip OA. 16 femoral heads were included in the study.
Cartilage explants were removed from 3 anatomical sites over the surface of 14 OA and 2 non-OA patients. Cartilage sections were evaluated with histological (EE, Alcian Blu and Mallory-Azan stainings) and immuno-histochemichal (antibodies directed against fibronectin, tenascin, laminin, type I and type IV collagen, metallo-proteinase-1,-2,-7 and -7) analysis.
Histological analysis of cartilage of central and per-hipheral biopsies from patients with severe OA showed significant reduced number of chondrocytes in both superficial and middle zones. In the lower cartilage layer with severe structural lesions a cospicous number of cartilagineous repair-islands were noticed. Immunohistochemical analysis showed high levels of tenascin in all cartilage layers of byopses showing structural damages. Frequently we observed an altered distribution of fibronectin. Metalloproteinase-2 (constitutive) is present in all stages during coxarthritis. Metalloproteinase-9 (not constitutive) is expressed at the final stages suggesting an important late role. Obtained results show that metalloproteinases have a peculiar behaviour during coxarthritis vs. other pathologies. Costitutive metal-loproteinases have a fundamental role in extracellular matrix remodelling, MMP-2 especially.
Patella resurfacing in revision total knee arthroplasty is a controversial issue. While performing revision TKA we must consider some different situations: previously resurfaced patella or not, in case of resurfaced patella, if it is fix or loosened, in case of loosened patella is there a bone loss or not. If patella wasn’t previously resurfaced, we can preserve natural patella performing at least a regularization of its osteophytes, or we can realize a primary resurfacing. If patella was previously resurfaced and still well fixed, we preserve domed component if not grossly damaged. Its revision is performed if it is damaged or not congruent. If patella was previously resurfaced and loosened the two possibilities are the revision or the retention of the bony patella. In case of previously resurfaced and loosened patella, with severe bone loss, we can preserve the bony shell, or we can realize revision with the use of cortical grafting or we can performa patelloplasty, or complete patellectomy. Finally, in these cases it’s possible the revision with tantalum patella. Outcomes of patella resurfacing in revision total knee arthroplasty are usually fair: low functional and pain scores, quadricipite leverage loss, worse patellar tracking, anterior pain, patellar fractures, knee stiffness.
The different spatial sideway of geodes in the same femoral head, their number, dimensions, origin, suggested to us the present document. Before now, it has already been analysed cystic hollows in primary arthrosis. Actually on our study, we relate the outcomes regarding the same phenomenon in rheumatoid arthritis.
Septic knee prosthesis revision is particularly challenging either for the eradication of the infection and for functional recovery of the patient.
18 patients treated from year 2000 to 2003, treated according to the same medical and surgical protocol have been reviewed. In all cases the following steps have been followed:
- removal of the septic prosthesis, debridement and implant of an articulated pre-formed cement spacer; - at 2 months, removal of the spacer and implant of a modular PFC knee revision prosthesis; - when appropriate osteotomy and synthesis of the anterior tibial tuberosity; - double antibiotic therapy, parentheral and oral, for 2 months after the first and after the second stage procedure.
At a mean 18 months follow-up, we observed:
- no infection recurrence in all cases (one patient is lost to follow-up); - range of motion: flexion 73° +− 25°, extension – 5° +− 3°; - 1 dislocation of the articulated spacer; - 1 femoral fracture.
Two-stage septic knee prosthesis revision, according to a the described protocol, allows to obtain high infection eradication rate and acceptable functional recovery, in the medium term follow-up.
In Italy the osteoporosis cause approximately 250000 fracture/year. A useful aid in the treatment of this pathology comes from the Teriparatide, a synthetic form of the natural human parathyroid hormone, that stimulates the formation of new bone by increasing the number and action of bone-forming cells, unlike estrogen and bisphosphonate which are only able in slowing or stopping bone loss by blocking the action of osteoclasts. The Authors presents theirs first results after treatment with 20 mcg per day of Forsteo (Ely Lilly), trade name of the teriparatide, along with calcium (1000mg) and vitamin D (400UI) supplementation, for the previewed maximum period of 18 months, in women older than 65 years with unsatisfactory bisphosphonate treatment, T-score equal or inferior to −4, multiple vertebral osteoporotic fractures and one or more age-independent factors risk like: BMI< 19 kg/m2, maternal familiarity with neck-femoral fractures before 65 years old, premature menopause, conditions associated with the extended immobility. The treatment induced in all patients an increase of Ca plasmatic concentrations for 16–24 hours with a maximum peak in 4–6 hours. Condition like hypercalcemia, severe renal insufficiency, renal calculosis, hyperpara-thyroidism, Paget, alkaline hyperphosphatasaemia and previous therapy radiating are the main parameter of exclusion from the treatment.
After the embryonic period, notochord remnants persist inside the intervertebral disc (IVD), where they give rise to the nucleus pulposus. Notochordal cells (NTCs) gradually disappear during maturation. This phenomenon is correlated with onset of disc degeneration. The objective of this study was to design a protocol for the isolation of NTCs to study his role in IVD regeneration.
Lumbar IVDs from immature rats were either enzymatically dissociated or mechanically taken out or cells isolation. Cells RNA extraction for PCR analysis was performed to assay Sonic and Indian Hedgehog (Ihh and Shh) and his receptor Patched (Ptc) expression.
NTCs were readily detectable in culture as large vacuolated “physalipherous” cells, with the enzymatic method. The cells isolated mechanically were enable to grow in monolayer while grown 2 weeks in a 3-D pellet culture. Ihh and Ptc was expressed in the cells isolated with both method, while Shh was expressed only in the cells isolated through the mechanical method.
Our findings show that the better way to isolate a pure population of NTCs is a mechanical extraction from a immature IVD. This is a first step in order to study his role for the regeneration of IVD.
We studied the efficacy of arthroscopic ACL repair for femoral avulsion of the ligament in ten patients (18 to 32 years of age). The tibial attachment and the midsub-stance of the ligaments were intact. We placed 2 mattress sutures with #2 fiberwire. The footprint of the ACL on the medial wall was decorticated and a guide drill was passed from inside-out followed by an endobutton reamer. The sutures were retrieved through the femoral tunnel using a small skin incision and tied over a button in full extension.
The rehabilitation included weightbearing with a hinged knee brace in extension, and CPM machine for the first month. The minimum follow-up was one year (mean 14 months). Lachman, Pivot shift, drawer tests, KT-1000 were documented. At 1 year all patients were stable. Sixty percent tested symmetric on KT-1000 and within 2 mm of the controlateral site. Forty percent had Lachman and anterior drawer within 1 grade and KT-1000 scores of > 4mm from the non-injured knee. None of the patients had a positive pivot shift. Our short-term data on arthroscopic ACL repair of a specific tear pattern are encouraging despite the negative outcome of open repair reported in the literature.
From June 2003 we have elaborated a new procedure consisting in an osteoinductive-antibiotic gel, positioned on the spongiosametal surfaces of the implant. The gel contains five elements: Cancellous bone chips, Platelet-Rich Plasma, Bone marrow, Fibrin glue, Vancomycin and Tobramycin. Blood loss, operative time Hemoglobin drop values and clinical results were collected. Our procedure shows a quickly osteointegration of the implants without septic complications due to the local delivery of antibiotics. The procedure is safe and easy because includes only autologous factors without risks of disease transmission or immune response.
The Pamidronate inhibits osteoclastic bone resorption and have been successfully used as an intravenous infusion in the treatment of fibrous dysplasia (FD) of the bone.
We describe the preliminary results of this approach in a 14 years old male patient with a monostotic fibrous dysplasia of the femur. A biopsy was performed before given the biphosphonate. He received 2 cycles of 180 mg intravenous infusion of pamidronate every months (60 mg/day for 3 days): Clinical symptoms, serum levels of calcium and electrolytes were valued during each treatment.
X-rays and BMD of total skeleton studies were performed at baseline and every 3 months. We observed a significant clinical improvement of the pain associated with the radiographic evidence of the thickening of bone cortex surrounding the lesion. Therefore, pamidronate seems to be a valid therapeutic option for patients with FD of the bone.
The authors studied the short-term results following patellar resurfacing using trabecular metal patella. Ten patients underwent primary (2 cases) or revision (8 cases) TKA with the use of a trabecular metal patella and were evaluated at a mean follow-up of 24 months. All patients had marked patellar bone deficiency or patellar absence precluding resurfacing with a standard cemented patellar button. The all polyethylene patella was cemented into the trabecular metal base and the remaining patella bone stock; additional fixation was provided by non-adsorbable sutures through the peripheral holes on the metal shell. No intraoperative complications occurred. There was no displacement of any trabecular metal patellar component and no patellar fractures. The fixation appeared excellent at three to six months radiographic evaluation with uniform bone contact in the peripheral regions in both lateral an Merchant radiographic views. The mean Knee Society scores improved in all patients.
Samples prepared with Karnowsky fixing and urani-lacetate solution. Fibril diameter and transversal area measured by LEICA QUIN in 5 cuts randomly selected for each sample.
Endoscopic methods of ACL reconstruction have shown some disadvantages such as the inability to freely position the femoral tunnel. Moreover, this technique dictates relatively vertical and central non anatomical graft placement compared to the more horizontal and lateral course of the native ACL. The ACL presents a collection of individual fibers that are grouping in two distinct bands, anteromedial (AM) and posterolateral (PL). The most anterior fibers of AM band are the most isometric. The majority of ACL fibers lie posteriorly to the isometric point on the medial wall of the femoral condyle. These fibers are lax during flexion and tight in extension. This behaviour was defined “favourable non isometry”. The “favourable non isometry” is very interesting because increased knee loading often occurs at flexion angles of less than 60 degrees. Classic two-incision technique, using a rear-entry drill, our two-incision technique, or the Clancy anatomic endoscopic technique using flexible reamers and use of different not commonly arthroscopic portals seems to allow a predictable, near-anatomic placement of femoral tunnel.
During Anterior Cruciate Ligament reconstruction, using bone- patellar tendon- bone graft, debris can accumulate in the joint. We assessed incidence and potential for complications, described the radiographic appearance and defined the natural history of these intrarticular debris in 50 consecutive reconstructions. The records and radiographs of 50 consecutive cases were reviewed. A stripe of radio-opaque material, resembling a comma, termed the “comma” sign, was noted behind the lateral femoral condyle on the early postoperative radiographs of 40 of the 50 cases. There was no statistically significant difference in loss of knee motion at six, twelve, twenty- six and fifty- two weeks postoperatively (P> 0.50) between the patients presenting the radio-opacity and those without it. A second set of radiographs was taken in 12 patients between 3 and 18 months postoperatively, revealing that this radio- opaque material was visible in 1 case only. No correlation was found between presence of radio- opacities and duration of pain, effusion, analgesia requirement, discharge timing, time to driving and time to work. A protocol of postoperative early weight- bearing mobilisation had been followed in all cases which may have played a role in promoting the faster dissolution of the debris.
In double bundle ACL reconstruction two tibial tunnels were drilled: for the anteromedial the 65 degrees Howell guide was employed; the posterolaetral was drilled through a prototype jig attached to the first guide. Two femoral tunnels were drilled outside-in with the Rear Entry guide. A 6 millimetres bovine tendon graft was employed and fixed to bone with interference screws.
Under an anterior drawer test double bundle ACL reconstruction restored anteroposterior laxity significantly better than single bundle reconstruction at 20 and 40 degrees of flexion. A trend towards a better rotational control of double bundle reconstruction was observed in extension.
Thirty patients with chronic lesions of the ACL underwent reconstruction of the ACL with double bundle technique. A wire at 65° was used for AM tibial tunnel and a prototype was used for the PL. For femoral tunnels, a transtibial technique was applied in fifteen patients and the outside-in technique was used in fifteen more. All patients had an MRI after three months. The tunnels position was studied with Amis’ circle method, as a proportion of the circle’s height and width. We compared the proportion of the anatomical data on fourteen cadaveric knees. In the transtibial group the AM tunnel was at 56% of the circle’s height and at 65%of the depth (mean); the PL was at 40% of the circle’s height and 54% of the depth. In the out-side group the AM tunnel was 48%of the circle’s height and at 66% of the depth; the PL one was at 32%of the circle’s height and at 61%of the depth. In corpses the AM insertion was at 50% of the circle’s height and 69% of the depth (mean). In conclusion the outside-in technique allows better anatomical positioning.
Investigation based on: Sport activity recover; IKDC; KT2000; isokinetical tests; muscular throphysm recover; Tegner and Lyshom score; Activity Rating Scale (ARS); Psychovitality Questionnaire; radio graphical evaluation in AP, LL and Rosemberg.
DB technique allows a faster sport activity and muscular throphysm recover and better results in the isoci-netical tests.
The kinematic effect of tunnel orientation and position, during ACL reconstruction, has been only recently related to the control of rotational instability.
This paper presents a detailed computer-assisted in vitro evaluation of two different femoral tunnel orientations with the same tunnel position, at 10.30 ‘o clock, during the intervention of ACL reconstruction with double bundle technique. Results highlighted better kinematic performances of the horizontal tunnel, with respect to the vertical one, in controlling antero-posterior (AP) laxities at 30°, and internal-external (IE) laxities.
Elongations of anterior and posterior bundles of reconstructed ACL, for both reconstruction, decreased during PROM respectively by 20% and 40%. Total length of the graft varied during PROM, mainly due to graft elongation during tests, graft length on horizontal tunnel varied from 237 to 213mm while graft length on vertical tunnel varied from 257 to 233mm. Kinematic tests showed a better performance of horizontal tunnel in the control of IE rotations at 30° and 90° and of the Lachman test with respect to the vertical one. Stability was restored with both reconstructions.
The efficacy of thermal modulation of collagen utilizing an electrothermal device to treat low to moderate demand patients with mid-substance anterior cruciate ligament tears was studied. Ten patients with partial ACL tear were treated with thermal modulation of the ligament. A chondral pick was utilized to create vascular inlet channels within the intercondylar notch. The mean follow up was 18 months (range of 12 to 36 months).
The patients ranged from 21 to 47 years of age. On the physical examination and KT-1000 testing eight patients had good to excellent clinical results, one patient an acute traumatic failure at 18 months and one a poor outcome. However the KT-1000 results deteriorated after one year.
There may be some benefit in treating moderate to low demand patients with this technology; however the long term results are unknown.
There have been very few studies evaluating the efficacy of thermal modulation of the ACL, and those studies have included patients who have previously undergone ACL reconstruction and have developed a loose graft. To our knowledge, this is the only study that evaluates primary ACL injuries, and utilizes vascular inlet channels to allow cellular population of the treated ACL.
Aim of this study is the investigation of lower limbs biomechanics before and after meniscectomy.
Data were acquired by means of Vicon motion analysis system
The dynamic analysis stresses alterations in knee sagittal moment. Before surgery the knee flexion moment is reduced. After partial meniscectomy the knee flexion moment increases in both the limbs. In squatting investigation, main focus was on repeatability. Before surgery high inter subjects variability affects knee joint angle; while after surgery high variability affects also hip and ankle.
The aim of this study was to evaluate the efficacy of Hyalograft®-C, in a group of patients with full thickness patellofemoral defects.
This tissue engineered osteochondral composite could represent a valuable model for further in vivo studies on the repair of osteochondral lesions.
The present study analysed the clinical outcome and the histological characteristics of membrane-seeded autolo-gous chondrocytes implantation at 24 month after surgery for chondral defects.
A prospectic study was performed on fifteen patients (8 males and 7 females, mean age 38 years) suffering from cartilage lesions of the knee (12 cases) and the ankle (3 case). The patients underwent matrix-induced autologous chondrocyte implantation (MACI). Clinical outcomes were assessed by revised IKDC form and Knee Osteoarthritis and Injury Outcome Score (KOOS). At 12 months after implantation biopsy samples were obtained from 7 patients. The specimens were analysed by histochemistry, immunohistochemistry (ICRS visual histological assessment scale) and histomorphometry (Quantimet 500+).
Improvement 12 months after operation was found subjectively (39.7 to 57.9) and in articular function levels. IKDC scores showed marked improvement at 12 months (88% A/B). 90% of biopsies showed: smooth articular surface, hyaline-like matrix, columnar cell distribution, viable cells, normal subchondral bone, tide-mark. All sections were clearly stained with safranin-O, alcian blue, and revealed immunoreaction for S-100 protein, chondroitin-S and type II collagen.
Clinical improvement and hyaline-like appearance of the repair tissue indicate that MACI implantation is an effective technique for the treatment of cartilage lesions.
A comparative prospectic randomized study has been performed between two groups of patients, one undergone to surgery by conventional technique (A) and the other by CAS (B). In all the patients the same type of prosthesis, Innex Ucor® (Zimmer), was implanted by the same surgeon. The surgical technique has been “tibia first” with preliminary ligament balance in both groups.
In CAS technique has been utilized the Navitrack® (Orthosoft) system integrated by an hydraulic tensor, Hydraulic Knee Analyzer® (Zimmer), able to measure the applied force and the obtained space.
Evaluation criteria have been: x-ray alignment (HKA), IKSS, SF-36. Minimum follow-up has been 12 months.
The data shows a statistically significant difference in the group B related to HKA (p< 0,0001) and functional score (p= 0,009). The knee score is “non significant” but it has a “tendency value”, even if the pain score is “significant” (p=0,008). SF-36 isn’t “significant”.
The group B has shown an important reduction of clinical and radiographic outliers.
This study identifies parameters that allow to foresee the necessity of soft tissue release (STR) before surgery. Femoral and tibial morphotype were defined evaluating several radiological parameters. Intra-operative STR during surgery was correlated to radiographic parameters identified. 33 cases were analysed and divided in 2 groups, release (6) no release (27), statistical evaluation has been performed using Mann-Whitney test and contingency tables for most relevant parameters. Three parameters were measured on femur and four on tibia.
The results confirmed the usability of angle between femoral anatomical axis and transepicondylar axis ATA (p< 0.001) and between femoral mechanical axis and tangent to distal condyles MCA (p< 0.001 ) as predictors, among tibial parameters angle between mechanical axis and tangent to tibial plateaux gives good results (p=0.028).The use of contingency tables highlighted that the combined use of ATA and MCA, gives better specificity than the use of a single angle.
Purpose of this experimental-prospective study on 35 total knee prostheses is to compare the data related to the bone cuts imposed during surgery using PIGalileo navigator and those really gotten and measured by TC scan examination at follow-up. PIGalileo navigator consists of a photogrammetric infrared camera that links a computer to three reflecting sensories fixed on femur and tibia. At follow-up, all the knees were submitted to a spiral TC analysis making a sequential 3 mm axial scans. In six cases (17%) it has not been possible complete the operation utilizing the navigator. Any statistically significance has been found regarding the mechanical axes of the femur and the tibia, the sagittal rotation of the femur and the horizontal rotation of the tibia. High level of statistical significance has been noted for the horizontal rotation of the femur (intraop: 3.7° extra vs. TC: 0.2° intra; p=.006) and for the sagittal rotation of the tibia (intraop: 6.2° post vs. TC: 3.5° post; p = .003). PIGalileo navigator has shown effectiveness to reproduce bone cuts respect the major axes of the knee but it has been less precise in rotation, mainly for the femoral cut.
The uncemented cup with iliac stem ensures immediate primary stability by fixation to the hipbone in acetabular loosening with severe bone defect. Homologous bone grafts contribute to restoring bone stock, which is a fundamental requirement for long lasting implant stability.
From 2002 to 2004 we implanted 23 cups with iliac stems in 22 patients. In 7 cases there was also stem loosening, and so total hip arthroplasty was performed. In 2 patients the defect was grade 2b, in 5 grade 3a, and in 16 grade 3b according to Paprosky. A direct lateral approach was performed in the supine position. Morselized bone grafts were used in all cases by the “impaction grafting” technique, and in 4 cases modelled structural grafts were also employed. Mean follow-up has been 18 months (8–32).
So far we have not had any cases of loosening. At follow-up x-rays showed remodelling of the grafts with integration.
The cup with iliac stem enables primary stability on healthy bone tissue, and protects the grafts form mechanical stimulation, thus allowing them to integrate and restore bone-stock. It also restores the centre of rotation, and provides functional benefits and implant stability.
A computer assisted technique for TKA Revision is presented. It is based on the use of a navigation system, RTKANav consisting of anl optical localizer, a dedicated software specifically done for TKA revision and some navigated tools developed for this application.
The system doesn’t use any patient model derived from medical images, but on the system interface patient anatomy model is represented with dots and lines corresponding to acquired landmarks and data derived from them. These data describe the main anatomical features and provide the surgeon with the main references for the intervention; angles between the mechanical axes can be controlled and monitored at any time.
Even if during acquisition phase some specific points can not be identified, since for each prosthetic component several criteria to set each degree of freedom are considered and compared, the system is always able suggest an intervention plan.
The system provides the surgeon with tools to analyse and modify the proposed plan, and to reproduce it on the patient.
Navigated technique validation is under development. Till now it was used on two patients by an expert surgeon. Computer guidance showed early promising results providing the surgeon with useful indications achieve a satisfactory prosthesis implant.
The use of extramedullary and intramedullary guides to prepare the tibial cut was studied comparatively in 100 consecutive primary total knee arthroplasties Low Contact Stress rotating platform. Each type of guide was used in 50 consecutive cases for a total of 100 cases. An ideal tibial alignment (90°± 2°) was obtained in 42 cases (84%) using the intramedullary system (IM group) and in 36 cases (74%) using an extramedullary alignment system (EM group) (p = 0.14). A posterior slope of 10° (± 2°) was achieved in 45 cases (90%) in IM group and in 40 cases (80%) in EM group 2 (p =0.16). The difference was not statistically significant but a greater accuracy was demonstrated when using an IM tibial alignment system.
Reasons for bone loss in septic hip prosthesis include osteolysis caused by the infection in itself and by the mechanical loosening, while implant removal and the necessary bone debridment usually ends in a even more severe bone loss.
In two stage revision surgery the use of a long stem antibiotic-loaded pre-formed cement spacer (Spacer G – Tecres s.r.l., Italy) appears particularly useful to allow mechanical stability and antibiotic local elution even in the presence of wide proximal femoral bone loss. After two months the revision is performed with non-cemented long stem modular implants (Profemur – Wright-Cremascoli) without the need for massive bone grafts. Recently we have also started using growth factors to stimulate bone stock reconstitution. In all the patients a double antibiotic therapy is administered after the first and second stage procedures for 6–8 weeks.
The results obtained (54 patients, follow-up 2 – 5 years) according to this protocol show the absence of infection recurrence, 10 cranial spacer dislocation, not treated, 2 revision prosthesis dislocations, that required open reduction, 1 transient femoral nerve palsy.
The described technique, used according to a proper protocol, allows to obtain good results, in the medium term follow-up.
We present 11 cases of total femur implanted in patients affected by severe bone defects in septic or aseptic prosthesis failures or tumours. Good results were obtained with a precise preoperative technical and surgical planning, without septic complications. We reported results and complications of our series.
BMPs, among which BMP-7 or OP-1, unlike several growth factors involved in new bone formation, are the only proteins able to start the whole process. That is BMPs are the only factors with osteoinduction ability.
Contrary to other growth factors, BMPs on the market are drugs.
RhOP-1, carried by collagen type 1, is the first osteo-inductive drug approved in the world for the clinical usage: in long-bone non-unions in US, Australia and Canada and in tibia non-unions, recalcitrant to autograft, in Europe (Osigraft).
We report data related to a retrospective observation on some patients treated in Italy with rhOP-1.
90 patients (66 with long-bone non-union diagnosis, 8 with delayed union, 7 with bone defect /bone cyst and the remaining with other pathologies) are reported, and efficacy results are showed on 60 patients with follow-up > 6 months.
Radiographic analysis shows that rhOP-1 is effective in 86,6% of patients. Unions have been reported in 34,8% at 4–5 months, and in 69,1% at 6–8 months.
Failure: 8/60 (13,4%). No adverse event has been reported.
These data are similar to those reported in literature in randomised and not randomised studies.
The treatment of relapsing pseudoarthrosis of ulna presents quite a lot of perplexities as regards the surgical strategy to follow which means of synthesis to solve the biomechanical problems (lack of favourable loading stimuli and, on the contrary, presence of unfavourable torsional strengths due to the movement of pronosupination of the forearm),and how to interact in order to favour the restoration of osteogenesis (homologous or autologous bone graft, vascularized or not, bone substitutes, employment of autologous growth factors, of morphogenetic proteins (BMP),and of autologous staminal cells).
The authors report about 4 particular cases of relapsing pseudoarthrosis of the ulna previously treated with autologous bone grafts but with no recovery.
In order to activate osteogenesis, the authors have employed a graft of autologous bone enriched with platelet derived growth factors + adult mesenchymal stem cells from drawing from the iliac wing. The osteosyntesis has been carried out in 3 cases with endomidollar locked nail and, in one case, with external fixation.
All the four cases have reached prompt lasting clinical recovery (following up from 8 to 28 month) and Rx precocious evidence of osteointegration of the grafts independently from the synthesis means.
The limited casuistry does not enable us to report any comparable statistical data.
The authors think that association of AGF + adult mesenchymal stem cells can be determinant and encouraging and, thanks to the results, they suggest its spreading.
The groups were thus divided:
Group 1: lyophilised bone chips.
Group 2: lyophilised bone chips + platelet gel
Group 3: lyophilised bone chips + platelet gel + packed autologous medullary cells (Buffy coat).
At six weeks X-rays, MRI and needle biopsies were carried out. The tissue underwent morphological and microstructural tests.
Results confirmed that the use of platelet gel and packed medullary cells as adjuvant for the lyophilised bone aid bone repair and graft integration. Morphological and morphometric tests showed that at six week the newly formed bone of group 3 had better mechanical properties.
Regulations and in force laws impose to obtain an informed consent prior to any care, especially in surgical setting. Such consent must be informed, explicit, personal, specific and aware. Aim of the present study was the drawing of an informed consent form to be used in external fixation.
The possible drawbacks of using external fixation have been divided in three main groups: general biological, local biological and external fixation related. Moreover, within this consent, a detailed patient compliance section has been included because of this particular fixation system, with regard on nursing, medications and treatment time. As for the specificity of indications in trauma, the pre-existing of risk factors as cigarette smoking or open fracture has been clearly stressed. Finally, the consent for hardware removal has been predisposed, too.
Haemophilia is a lifelong inherited bleeding disorder characterized by spontaneous bleeding resulting in painful joint deformities. Even if prosthetic surgery and the effectiveness and safety of clotting factor concentrate have improved the therapeutic options available, sometimes the orthopaedic surgeon has to treat substance losses. First, we have to distinguish: 1) sub-chondral cysts, 2) intra-osseous cysts, 3) pseudo-tumour (a chronic expanding blood cyst with the ability to displace and destroy adjacent tissues) Surgical treatment is in relation to its anatomical location and extension and is always associated with prolonged treatment with clotting factor concentrate. In our 20 years’ experience, we have used several therapeutic options. In some cases, we use filling with bone graft and fibrin seal and today platelet derived growth factor; in the others we have used amputation or custom made prosthesis.
Acetabular loosening is often dangerous because the patient is pain free for several years. The following bone loss may represent the biggest challenge in revision surgery.
Object of this study is to evaluate the use of an iliac stem cup (Link®) associated with impacted bone grafts in acetabular loosening and CDH.
We performed 25 implants in loosening (13 grade 2 and 12 grade 3 of Paprosky): average age was 68 years old in 16 female and 9 male. Mean follow up was 22 months.
We used bone grafts in 17 cases. In 1 case we cemented the Mcminn cup because of poor initial stability with no complication at 18 months.
We noted radiolucency lines < 2 mm. in 1 case and bone resorption in 2 cases. The complications were: malpositioning of the stem (1%), sacroiliac pain (4%), superficial infection (2%) and DVT (1%).
In conclusion, we can affirm that McMinn cup, despite a demanding surgical technique, represents a valid alternative to acetabular revision surgery because of the good initial stability, the respect of loading lines and besides it allows the use of pressurized bone chips.
Loss of bone stock resulting from wear particle-induced osteolysis may compromise the stability and osteoin-tegration of arthroplasty implants. Usually allogeneic corticocancellous bone is used around an implant to fill the defects, but because of the safety and availability of these grafts, the use of synthetic substitute of bone is becoming everyday frequently. BoneSave™ is an osteo-conductive biomaterial prevalently used in reconstructive surgery but it can be used to fill every bone defects or in traumatology like adjuvant of an osteosynthesis. The particles of BoneSave™ (2–4 mm or 4–6 mm) are made of tricalcium phosphate 80% and hydroxyapatite 20%, they have a superficial porosity of 50% (range 10–400 mm). Usually the osteointegration happens after 2–3 years. Recently studies have described that the mixture of 80% TCP/20% HA with human mesenchymal stem cells induced bone formation in vivo faster than the other formulations of the same elements, In vitro studies also demonstrated the expression of osteocalcin. The mixture of TCP/HA with bone-marrow aspiration could be useful if human stem cells are not available. Orthopaedic and traumatology cases will be shown where the use of Bone-Save™ has lead to good clinical and radiological results after a follow-up of 24 months.
A new island fasciocutaneous flap raised on the inner surface of the upper arm has been used for reconstruction of soft tissue of the elbow as described by Maruyama in 1987. The medial arm represent a very useful potential donor site for flap because of its excellent colour, fine texture and ideal thickness. The flap sa described by Maruyama achieves a good coverage of the defects of the elbow region and results extremely suitable for contracture and ulcers treatment at the elbow region as we can see after burns or other various trauma and lesion. The blood supply to this flap comes from the fasciocutaneous perforators of the ulnar recurrent vessels. In our experience this flap is relatively quick and simple, involving only one stage procedure that adequately corrects the skin defect around the elbow region.
In amputation or amputation-like injuries of lower limbs, only in a few cases reconstructive treatment with microsurgery is encouraged, according to evaluation of lesion by Mangled Extremity Severity Score (MESS). Replantation cases may require substantial bone shortening, as consequence to seriousness of the trauma or a deliberate choice to enable primary vessel and nerve repair. Callus distraction technique by external fixation, circular or axial, is a common method for recover lengthening in these cases of replanted or revascularized extremities.
We report six cases of lower limb replantation or revascularisation, with primary bone shortening from 3 to 7 cm and secondary lengthening by callus distraction.
It was always obtained equalization of lower extremities, with successful rehabilitation of the patients and low onset of complications during treatment.
Hig energy fractures of the lower limb are often associated with tibial or femoral bone loss, skin exposition with vascular and nervous injuries (Gustilo et al.).
The surgical procedure is a real challenge, consisting in a temporary stabilization of the fracture associated with a plastic and/or vascular reconstruction.
Once the skin and vascular injuries are recovered, the orthopaedic surgeon can remove the temporary stabilization performing a circular external fixation with bone lengthening by using the “bifocal” (one site of metaphiseal corticotomy and one site of compression) or “trifocal” (two sites of metaphiseal corticotomy and one site of compression) technique.
We use to do a “docking site” treatment when bone fragments are nearly in contact.
Our experience indicates that circular external fixation, by using the Orthofix system, is a very useful and safe technique in the management of severe lower limb injuries.
Our good clinical results lead us to suggest this surgical technique that allow to obtain a limb reconstruction, avoiding segment amputation.
The aims of the treatment of tibial infected nonunions with bone and soft tissue loss (generally consequent to open fractures) are: the healing of infection, the bone consolidation with preservation of lower limb length and the reconstruction of soft tissue loss. The epider-mato-fascio-osteoplasty according to Umiarov (a modification of bifocal or multifocal compression-distraction osteosynthesis) enables to treat wide areas of bone and soft tissue loss without a preventive sterilization of the infection neither soft tissues closure and without bone and skin grafts. An important point of the treatment is the prevention of complications such as: persistence of infection (due to an insufficient debridement), trouble in formation of bone regenerate and /or callus at the docking site (due to inadequate configuration of the external fixator, imperfect management of the phases of treatment, obstacles on bone transport), defect of skin coverage (due to an improper rate of bone and soft tissue transport), complications at the site of application of the device (inflammation or infection, breaking of the fixation elements), functional impairment (knee and ankle stiffness).
In the 54 patients treated the anatomical and functional results have been particularly favourable, thanks to an accurate preoperative planning and a careful postoperative management, diminishing the risks of complications.
Primitive malignant neoplasms affecting the distal third of the tibia are altogether rare. The authors describe the diagnostic procedure and surgical strategy of limb salvage in a case of malignant fibrous histiocytoma in this region, in a 50-year-old male. In this anatomic region, considering the limb salvage surgery, there are different reconstructive possibilities, as ankle prosthesis and arthrodesis with or without vascolarized fibula. The Authors underline the infective and mechanic problems of these surgical solutions, proposing a different arthrodesis. The surgical treatment consisted in resection of the distal third of the tibia and fibula. The restoration of the skeletal continuity has been obtained by a locked nail. The mechanical resistance of the system has been obtained by acrylic cement. A vascularized myocutaneous flap allowed the cover of the resection area. About 28 months after surgical intervention, the patient is now able to walk without the aid of the knee stabilizer nor the sticks; without signs of local recurrence of the disease, metastases, with no implant failure, nor of the cement. The very favourable outcome of the clinical case previously described should make this method be looked at as one of the available surgical options in treating these lesions.
Three cases of patients affected with massive bone defects are reported, in which over 50% of the segments are involved. The treatment options considered were original and not yet described in literature. The patients were affected with: partial agenesia of the tibia, congenital hypoplasia and pseudoarthrosis of the femur, and massive post-traumatic bone defect. In all these cases the Ilizarov’s method was applied. In the first case, instead of carrying out an osteotomy and callotasis of the residual bone tissue, an osteotomy was performed close to the tibiofibular syndesmosis and a distraction at this level was executed. In the second case of pseudoarthrosis with antecurvatum of the proximal femur of 135°, varus of 100°, length discrepancy of 63%, a multiplanar gradual correction of the proximal deformity of the femur was carried out followed by a distal lengthening.
The third case concerning the pluri-fragmented exposed diaphyseal fracture of the tibia and fibula, with massive bone loss, was treated by restoring all the small fragments, even those without periosteal connections, to increase the proximal and distal bone mass. Once the fusion of the fragments occurred, a proximal osteotomy and callotasis was performed to rejoin the fracture’s segments.
We have treated 17 patients with bone defects of the tibia by internal bone transport using a stacked Taylor Spatial Frame.
There were 12 cases of infected non unions, 2 cases of osteomyelitis, 1 case of acute traumatic bone loss, 1 case of non union in a patient with neurofibromatosis, and 1 case of pseudoarthrosis of the tibia.
The mean bone defect was 51.8mm (range 10–100mm).
Leg length has been restored to within 10mm in 16 cases and to within 15mm in one case. All patients have united.
Residual deformity at the docking site or regenerate was negligible in 4 patients and less than 5 degrees in any plane in the remaining 13 patients. There have been two cases of re-fracture which have united with conservative treatment and 1 case of partial peroneal nerve palsy which is recovering.
The use of a stacked Taylor Spatial Frame system is effective in mediating bone transport resulting in predictable regenerate, accurate docking and minimal induced bone deformity.
53 patients underwent closed reduction and longitudinal k-wiring of displaced Colles’ fractures and were reviewed after a mean of 26 months. Radiographs taken at the time of injury, after reduction and k-wiring, and at fracture union were compared for radial shortening and dorsal angulation. Manipulation significantly improved fracture position (p< 0.001). Dorsal angulation was successfully corrected by manipulation in 98%, and this position was maintained to fracture union in all cases. 73% of fractures manipulated for radial shortening > 2mm were adequately reduced, but 41% of these fractures subsequently lost position to malunite. The mean shortening between reduction and fracture union was 1.6mm. This did not correlate with Frykman Class or radial shortening at injury.
Closed Reduction and k-wire stabilisation is an attractive technique because it is relatively non-invasive compared with plating or external fixation. However, a degree of radial shortening between reduction and fracture union must be anticipated. Fractures reduced inadequately to allow for this loss of radial length, are more likely to malunite.
This may compromise functional outcome.
Arthroplasty is the most effective management of displaced intracapsular femoral neck fracture. Hemiarthroplasty (HEMI) is associated with acetabular erosion and loosening in mobile patients and total hip arthroplasty (THA) with instability.
We sought to establish whether HEMI or THA gave better results in independent mobile patients with displaced intracapsular femoral neck fracture.
Eighty-two patients were randomised into two groups. One arm received a modular HEMI, the second a THA using the same femoral stem. Patients were followed for a mean of three years after surgery.
After HEMI, eight patients died, two were revised to THA and there is intention to revise three. One patient had a periprosthetic fracture. Mean walking distance was 1.08 miles and Oxford Hip Score (OHS) 22.5. Twenty patients (64.5% of survivors) had radiological evidence of acetabular erosion.
After THA, four patients died, three dislocated, one required revision. Mean walking distance was 2.23 miles and OHS was 18.8.
HEMI is associated with a higher rate of revision than THA and potential revision because of acetabular erosion. THA after three years displayed superior walking distances (p=0.039) and lower OHS (p=0.033).
THA is a preferable option to HEMI in independent mobile elderly patients with displaced intracapsular femoral neck fracture.
Decreased head-neck ratio diameter and component malposition in total hip arthroplasty are factors known to result in impingement, increased rates of dislocation, wear and failure. In addition to these complications, impingement of the femoral neck on the acetabular component of a hip resurfacing may result in femoral neck fracture and loosening of the acetabular component. Little is known regarding the optimum femoral and acetabular hip resurfacing component position to avoid impingement.
In the first part of this study we analysed the radiographic component position of 131 consecutive hip resurfacings. In the second part the effect of three component variables on the range of motion to impingement were analysed using a dry bone model:
Inclination of the acetabular cup Version of the acetabular cup Femoral head-neck diameter ratio
The mean femoral-stem shaft angle in the first part of the study was 138° (range 121° to 158°). The mean acetabular inclination angle was 45° (range 30° to 63°). This wide range in position mirrors that described in the literature. The dry bone study revealed an optimum acetabular cup inclination tending towards 50° and an anteversion of 25°. A large diameter femoral head relative to the femoral neck resulted in a greater range of motion to impingement. A fine balance however exists, to remove a minimum amount of pelvic bone to accommodate a larger acetabular component with an ‘oversized’ femoral component.
The acetabular resurfacing cup positions described allow the greatest range of physiological hip movement. New technology and improvements to existing equipment and techniques will hopefully lead to more accurate placement of hip resurfacing components minimising the risk of impingement and its complications in this high demand group of patients
The optimum approach for Total Hip Arthroplasty is hotly debated. Many surgeons, especially the newly trained, have been wary of the
We analysed 137 consecutive patients who underwent Primary Total Hip Replacement for Osteoarthritis during the first three years of practice of a newly appointed consultant with an interest in hip and knee arthroplasty. All surgeries were either performed by or under the direct supervision of the senior author. The posterior capsule and short external rotators were reattached to the Greater Trochanter as a routine.
Data was gathered prospectively by proforma for all the patients, one at the time of operation and one each at 3 months and 12 months from the surgery. 4 patients died due to causes unrelated to their arthroplasty (2.9%) and 6 patients (4.3%) were lost to follow up.
The patients were grouped into A, B and C depending on involvement of one hip, both hips and multiple joint diseases respectively and the patients were analysed for pain scores (1–6), function scores (1–6) and satisfaction levels (1–5) after the surgery. All the complications during and after surgery were noted, and special emphasis was laid on the incidence of dislocation, and factors contributing to it. The results were compared with the incidence reported in the literature for posterior and other approaches.
The results were gratifying and were comparable with major series of Total Hip Replacement via the posterior approach. Only one patient (0.7%) had a dislocation. This occurred during the index admission when the patient sat down on a ward toilet without a raised toilet seat. The hip was reduced under General Anaesthesia and he had no problem thereafter. 122 patients (96%) had no pain or minimal pain not limiting the activity after the surgery but 5 patients (4%), 3 from Group C had activity related pain or pain at rest. 93 patients (73%) were walking without a stick after surgery and 34 patients (27%) were using a stick for extra safety. 5 patients (4%) had superficial infection which settled with antibiotics and one patient (0.7%) had deep infection which required a Revision hip surgery. 6 patients developed Deep Vein Thrombosis (4.7%) and one patient (0.7%) had Pulmonary Embolism but all the patients returned to good function after treatment. One patient (0.7%) developed transient Sciatic nerve palsy but recovered completely.
We conclude that the posterior approach, already known to cause less blood loss and to allow optimum component positioning and alignment, is compatible with a low overall rate of early complications. Specifically, the dislocation rate is low and comparable with large series performed by approaches traditionally considered to carry a lower rate of dislocation.
Since Aug‘03 pre-operative MRSA screening & a ward reserved exclusively for MRSA free joint replacement patients has been used. All postoperative wound infections within 3 months following THR & TKR were monitored.
Before screening, 0.59% of 3386 were acutely infected with MRSA. After institution of study policy, 0.10% of 1034, were infected with MRSA.. This was a 6 fold decrease (p< 0.05). The rate of MRSA infection in a control of hemiarthroplasties was unchanged during this period.
A policy of MRSA screening & an MRSA free joint replacement ward reduces the incidence of acute MRSA infections.
We report results using the hydroxyapatite coated, distally locking Cannulok revision hip prosthesis. The component was used to treat periprosthetic and pathological fractures, often in the presence of aseptic loosening or infection in a group of elderly patients. 16 patients with a mean age of 78 years underwent surgery by a single surgeon over a period of 3 years. They were followed up clinically and radiologically for an average of 24 months.
The mean modified Merle D’Aubigne and Oxford Hip Scores were 14 and 23.6 respectively. These results are comparable to the published results for the previous version of the Cannulok hip, and other revision hip revision series.
We believe the implant provides a relatively simple and effective reconstructive option that can be used as an alternative to more extensive surgical options in elderly patients with periprosthetic fractures.
We have assessed the clinical and radiological outcome of traumatic knee injuries resulting in open reconstruction of the posterior cruciate ligament using synthetic ligaments at the University of Toronto, Ontario. Pre and post-operative stress radiographs at 30 and 90 degrees were performed, along with IKDC, Lysholm and Tegner scoring.
Between 1995 and 2002, 11 patients were operated on. The average time to surgery was 42.3 months (range 1 to 252 months). The average age at time of surgery was 34.1 (26 – 48). The length of follow up ranged from 6 to 87 months.
IKDC scoring showed that no patient returned to normal. 5 were nearly normal, 4 abnormal and 2 severely abnormal. The average Lysholm score was 83 (58 – 95). 2 scored excellent, 6 good, 2 fair and 1 poor. The average Tegner score pre-injury was 6.3, prior to surgery 1.8 and post-operatively 3.9 (twice weekly jogging). Stress radiographs showed a decrease in antero-posterior laxity at 30 and 90 degrees although statistical significance was not achieved (p = 0.229 and 0.474 respectively).
We conclude that PCL reconstruction restores the normal biomechanics of the knee allowing a more normal function. The synthetic ligament allowed early weight bearing and range of movement mobilisation. The Tegner scores showed a considerable improvement from pre to post-operative values. The stress radiographs showed a decrease in the antero-posterior laxity. Although the IKDC scores did not show any normal knees post-operatively, this was expected due to the severity of the initial injuries.
The authors recommend the use of synthetic ligaments to reconstruct the PCL.
Trampoline was used by British & American fighter pilots as a training device during World War II. It became popular among Civilian as a recreational sports during 50s and 60s. Trampoline related injuries including quadriplegia and death have been reported from United States and Europe. We are reporting the incidence, type and distribution of trampoline-related injuries in children in a District General Hospital in United Kingdom.
Recently we treated three serious injuries – proximal tibial fracture associated with popliteal artery injury, subtrochanteric fracture of femur and cervical fracture-dislocation leading to quadriplegia, that lead to an audit study. This is a retrospective analysis of trampoline-related injuries in children seen in the Accident & Emergency Department over three months period. The casualty cards and admission records were reviewed.
The mechanism of injury was fall on or off the trampoline in 98.15%(53/54). All injuries occurred on back-garden or leisure-centre trampoline. 74% of injuries were sustained while unsupervised.
The incidence of soft tissue injuries were 59.25%(32/54) and fractures 40.75%(22/54). Soft tissue injuries commonly involved lower limb(16), upper limb(7) and head and neck(4). Fractures commonly involved upper limb(13), lower limb(8) and nasal bone(1). The fractures involved wrist and forearm in eight cases, ankle in five, elbow in four and one case each involving finger, hip, knee and toe. The treatment of trampoline-related injuries varied from reassurance, analgesia, tubigrip bandage to plaster cast. Fourteen(26%) patients were admitted into the wards and ten(18.5%) required surgical treatment.
The incidence of trampoline-related injuries in back-garden and leisure-centre when unsupervised was high. The supervision by an adult has not proved to be very effective in preventing the injuries as 26% of trampoline-related injuries occurred under supervision of an adult.
The morbidity related to leisure trampolining is high probably due to lack of training and non-compliance to the manufacturer instructions in the use of trampoline. We would recommend banning the routine use of back garden trampoline without proper training and supervision.
A modern craze is the Harry Potter series of books. UK sales of the latest book, The Half-Blood Prince, are estimated to reach 4 million. Given the lack of horizontal velocity, height, wheels or sharp edges we were interested to investigate the impact the books had on children’s traumatic injuries.
The launch dates of the most recent two books (Order of the Phoenix and The Half-Blood prince) were identified and the admissions for these weekends were compared to surrounding summer weekends and those dates in previous years.
Data were obtained from MetOffice (
MetOffice data suggested no confounding effect of weather.
Our vascular injection studies indicate that the blood supply to triceps brachii is proximally based. We used a posterior approach identifying the ulnar nerve. We mobilised lateral triceps and anconeus in continuity preserving the vascularity and separated the components of distal triceps through an intermuscular septum. The fractures were reduced and fixed using K wires.
Reconstruction was done by a standard 4-strand hamstring technique using an endobutton proximally and a spiked washer and screw distally in the tibia.
The IKDC, Lysholm and Tegner scores were used to assess the knees pre and post-operatively. Stability was measured using the KT-1000 arthrometer.
Theoretical advantages of a one stage open reduction includes shortened hospital stay, avoidance of prolonged repeated immobilization and decreased joint stiffness. This study reports the results of single stage combined procedure for late presenting congenital dislocation of the hip in children aged 4 years and above.
Patients had improvement of pain, posture, hip instability, walking ability and limb length discrepancy. The median lengthening of the femur was 3 cm (2–5). The mechanical axis was realigned in all patients. All patients were satisfied with the outcome. Planned secondary contra lateral epiphyseodesis was required to equalise leg length in 2 patients. Complications included a stiff knee (1) that required a Judet quadricepsplasty, premature consolidation (1) that required reosteotomy and knee subluxation (1) that required cross knee stabilisation.
We changed our pin tract care practice from 1996. We had a significant decrease in pin tract infections since then (p< 0.0001). We also found that using Ilizarov wires had significantly less infections than with half pins used with monolateral fixators (p< 0.0001; linear trend, p= 0.0338). There were 48 patients that required hospital admissions for IV antibiotics. and of these 10 patients required debridement. There were no residual long lasting infections or chronic osteomyelitis.
Percutaneous drill epiphyseodesis is an effective method of achieving physeal ablation with no significant complications. While the growth remaining method is a crude estimate of the timing of epiphyseodesis, it was accurate in the majority of cases in this small series. The determination of skeletal age was found to be a useful adjunct to management in a small proportion of cases.
Navigation is the combination of real and virtual anatomy. Registration brings the virtual world of imaged anatomy into accordance with the real world of actual anatomy. Without a navigation system the process takes place in the head of the surgeon, he assigns the image data to the patient’s anatomy, based on his experience. This process is called mental registration.
Registration methods: Every point in the patient’s anatomy correlates to one point in the three-dimensional image of the patient. Every point in the anatomy and the image can be clearly defined as a position vector in a Cartesian coordinate system. Registration is carried out by a series of transformations of the different Cartesian coordinate systems. The registration between the real and the virtual world can be performed manually or automatically. Different technologies are available for this process.
In the Paired Points Matching landmarks, which can be clearly identified in the image dataset and in the in situ anatomy, are registered pre-operatively in a three-dimensional (e.g. CT) dataset. At least three points, registered as precisely as possible in the dataset and the intra-operative anatomy, are necessary to define the spatial position of the dataset and to bring it into correlation with the patients anatomy. On the spine, the existing prominent landmarks on the accessible dorsal part of the vertebrae, the dorsal process, and the joint condyles are used. Different factors contribute to an inaccurate registration, like an inadequate preparation of the anatomic structure, a misinterpretation of the landmarks by the surgeon, or anatomic variations, that formed in the time between the CT images and the operation.
The definition of corresponding point pairs can be difficult in many applications and an increased degree of invasivity must be accepted. Therefore, the precise recognition of the predefined points of the image dataset in the patient’s anatomy is severely impaired. However, other characteristics, e.g. curves or surfaces of bones can be extracted from the image data. These form the basis for the Surface Matching. A series of points on the surface of the bone must then be digitalised intra-operatively. This accumulation of points is then transferred to the corresponding virtual surface with the help of a complex mathematic algorithm, so that the gap between the points and the surfaces is minimized.
Under special circumstances the registration can be carried out automatically. For this it is necessary that the position of both coordinate systems is known at the time of image recording. To do this, a reference array needs to be attached to the patient and thus the automatic registration can only be performed intra-operatively. In general, all available intra-operative imaging equipment can be used.
Bulky equipment, such as computer tomography or magnetic resonance imaging is available intra-operatively only in very few facilities. The most valuable source for intra-operative images is the image intensifier. Images can be recorded with a navigated, calibrated C-Arm in the standard positions relevant for the surgery. Several fluoroscopic image layers can be displayed at the same time as optical information in the operating room in the form of a permanent virtual fluoroscopy.
Since 2001 a fluoroscopic image intensifier is available, which can generate three-dimensional multilayer reconstructions of high-contrast objects, like bones, from single fluoroscopic images. Since the introduction of three-dimensional imaging techniques in navigation, it is possible to perform the automatic registration of three-dimensional data. So, the above described limitations of CT-based navigation for minimal invasive surgery, e.g. not being able to update the dataset and errors during manual registration, were taken into account. However, the process of automatic registration is highly complex and influenced by many factors.
The use of surgical navigation in computer assisted or image guided procedures requires the precise measurement of the spatial position of surgical instruments. Investigations of several physical principles have turned out that two technologies are best feasible for application in clinical routines: a) optical technology, b) electromagnetic technology. Available systems based on either principle deliver measurement information for the 3D-position of a surgical instrument, expressed by the x-y-z coordinates of its tip, and for its 3D-orientation, described by the direction of the instrument axis towards the tip. It is therefore common terminology to describe such measurement systems as 3D/6D digitizing or localizing systems.
The presentation will describe basic principles of both technologies, including their main technical features and the design of key components such as rigid bodies for optical systems and sensor coils for electromagnetic systems. The survey includes an overview of known challenges and problems, and how commercial systems cope with these. A comparison of both technologies outlines the advantages and drawbacks in different applications as well as possible future improvements. It leads to the conclusion that both technologies will co-exist for the foreseeable future.
Measurements of a patient’s anatomy are often made in two different forms, for instance from a computer tomography (CT) scan and by direct measurement of the anatomy, or when comparing a CT and a magnetic resonance imaging (MRI) scan or at different times. Therefore, it is almost inevitable that the patient will be measured in a different position each time, since the relative position between the patient and the measuring or scanning device will be different. To align the patient’s anatomy between these different measurement systems a process of registration is used. This is necessary in a number of fields including computer assisted navigation, robotic assisted surgery and diagnostics.
Computer assisted surgery (CAS) generally involves “patient to modality” registration, as, in any CAS application that involves planning, the relationship between the modeled space (where the procedure is planned) and the patient’s workspace (where the procedure is executed) needs to be established. Patient to modality registration involves the registration of patient-specific anatomy with an image acquired using one of many modalities. It is usually associated with intra-operative registration, where the actual patient’s position needs to be known with respect to a pre-operative or previously acquired image. Even though the acquisition of patient-specific information may itself involve the use of a modality, the purpose of the process is to register the patient’s position against the model. The two co-ordinate systems to be registered belong to the patient and to the modality used to acquire the registration image, respectively.
In “image-based” methods, identifiable features, such as fiducial marker screws or anatomical landmarks, are first extracted from the model, which is generally reconstructed from CT images, and then “sensed,” or located, in the operating theatre. This process provides the system with enough positional information for the model’s and patient’s spaces to be registered against a common co-ordinate system.
In recent years, the CAS community has seen a shift to “image-free” methods, where both the plan and registration process are carried out without any prior knowledge of the patient’s anatomy. The pre-operative image acquisition stage is avoided altogether, and the planning is executed intra-operatively during surgery. A complete functional model of the patient is reconstructed from anatomical landmarks sensed intra-operatively and, in some instances; intra-operatively acquired surface information is used to “morph” a standard anatomical atlas to resemble that of the patient.
Image-free methods offer the prospect of no pre-operative imaging or planning, however their value, in terms of intra-operative workflow and accuracy of outcome, has yet to be assessed when compared to image-based methods.
A major limiting factor for the accuracy in Computer Assisted Surgery (CAS) is the system’s positional knowledge of the patient’s anatomy, derived through the process of registration. In computer assisted Minimally Invasive Surgery (MIS) the registration process is made more difficult by the lack of direct access to a large portion of the surface to be registered. Current experience with a hands-on robotic surgery system, which uses a set of points measured with a mechanical digitiser on the exposed surface of the bone and a surface reconstructed from computer tomography (CT) data, has shown that accurate and robust registration is still possible through an MIS approach.
The registration method described here, which was originally developed for robotic assisted total knee arthroplasty (TKA), has successfully been adapted for robotic assisted unicompartmental knee arthroplasty (UKA) and computer assisted hip resurfacing (HR). Results show that good registration can be achieved by registering the bone surfaces through conventional surgical incisions, with two additional stab-wounds required for the UKA procedure. However, experimental results suggest that, because of the limited access resulting from a smaller incision, a good correspondence between the point-set and surface measurements (i.e., better than one millimeter) is necessary for registration accuracy better than two degrees and two millimeters. This degree of correspondence can be expected for a good surface model and an appropriate intra-operative setup, but poses an important constraint on the requirements for a system suitable for this type of procedure, if a registration method based on anatomical features is to be used without the need for additional access.
The Phantom based Computer assisted orthopaedic surgical system (CAOSS) has been developed collaboratively by the University of Hull and the Hull Royal Infirmary, to assist in operations like dynamic hip screw fixation. Here we present summary of our system.
CAOSS comprises a personal computer based computer system, a frame grabber with video feed from a C-arm image intensifier, an optical tracking system and a radiolucent registration phantom which consists of an H arrangement of 21 metal balls. The phantom is held in position by the optically tracked end-effector. Knowing the optical position of the phantom, a registration algorithm calculates the position of C-arm in coordinate space of the optical tracking system.
Computer based planning uses an anteroposterior (AP) and lateral image of the fracture. Marks are placed on the 2D projections of femoral shaft, neck and head on the computer screen, which are then used to create 3D surgical plan. The computer then plans a trajectory for the guide wire of DHS. The depth of the drill hole is also calculated. The trajectory is then shown on both AP and lateral images on the screen.
CAOSS meets all the requisite of electrical and electromagnetic radiation standards for medical equipment. There has been extensive validation using software simulation, performance evaluation of system components, extensive laboratory trials on plastic bones. The positional accuracy was shown to be within 0.7mm and angular accuracy to be within 0.2°. The system was also validated using Coordinate Measurement Machine.
Our system has the unique feature of the registration phantom which provides accurate registration of the fluoroscopic image.
The movement of a normal knee is a complex of flex-ion-extension, translation and rotational movements. Intracapsular anatomical structures such as ACL, PCL, menisci, the bone anatomy as well as the muscles acting on the knee joint influence the screw home mechanism.
We assessed the axial rotation of the tibia during knee flexion in order to better understand the kinematic behavior of osteoarthritic knees.
We included 55 consecutive admissions (31 females and 24 males) with diagnosed osteoarthritis of the knee. All records were obtained by consultant orthopaedic surgeons using the trackers and software of a navigation knee replacement system, prior to a knee replacement surgery. All the records were obtained before any soft tissue release.
For the statistical analysis we used the Wilcoxon non parametric two sample test.
We found that the tibial rotation on knee flexion followed three distinct patterns: a) normal rotation: 26 knees (47%) with average rotation of 15.96° (range: 0.5°–34°). b) mixed internal and external rotation: 22 knees (40%) with average rotation 6.7° (range: 5°–0.5°) and c) reversed rotation: seven knees (13%) with average external rotation of 2.7° (range:1°–4°).
Most of the tibial rotation occurs in the first 0–30° of flexion (70%) p< 0.001.
Our study confirms that osteoarthritis affects the normal kinematics of the knee joint and also suggests that the observed kinematics follow distinctive patterns.
Computer aided joint replacement surgery has become very popular during recent years and is being done in increasing numbers all over the world. The accuracy of the system depends to a major extent, on accurate registration and immobility of the tracker attachment devices to the bone. This study was designed to assess the forces needed to displace the tracker attachment devices in the bone simulators.
Bone simulators were used to maintain the uniformity of the bone structure during the study. The fixation devices tested were 3mm diameter self drilling, self tapping threaded pin, 4mm diameter self tapping cortical threaded pin, 5mm diameter self tapping cancellous threaded pin and a triplanar fixation device ‘ortholock’ used with three 3mm pins. All the devices were tested for pull out, translational and rotational forces in unicortical and bicortical fixation modes. Also tested was the normal bang strength and forces generated by leaning on the devices.
The forces required to produce translation increased with the increasing diameter of the pins. These were 105 N, 185 N, and 225 N for the unicortical fixations and 130N, 200N, 225 N for the bicortical fixations for 3mm, 4mm and 5 mm diameter pins respectively. The forces required to pull out the pins were 1475N, 1650N, 2050N for the unicortical, 1020N, 3044N and 3042N for the bicortical fixated 3mm, 4mm and 5mm diameter pins. The ortholock translational and pull out strength was tested to 900N and 920N respectively and still it did not fail. Rotatory forces required to displace the tracker on pins was to the magnitude of 30N before failure. The ortholock device had rotational forces applied up to 135N and still did not fail. The manual leaning forces and the sudden bang forces generated were of the magnitude of 210 N and 150 N respectively.
The strength of the fixation pins increases with increasing diameter from three to five mm for the translational forces. There is no significant difference in pull out forces of four mm and five mm diameter pins though it is more than the three mm diameter pins. This is because of the failure of material at that stage rather than the fixation device. The rotatory forces required to displace the tracker are very small and much less than that can be produced by the accidental leaning or bang produced by the surgeon or assistants in single pins. Although the ortholock device was tested to 135 N in rotation without failing, one has to be very careful not to put any forces during the operation on the tracker devices to ensure the accuracy of the procedure.
Computer assisted navigation (CAN) has been shown to significantly improve the overall alignment obtained after total knee arthroplasty (TKA). Human error and the use of conventional jigs may be the reasons for the inaccuracy of conventional TKA. The impact of computer assisted equipment in surgeon training has not yet been established.
Three orthopaedic trainees participated in this prospective study to assess the impact of CAN upon intraoperative alignment. Each trainee’s first five (early group) and last five (late group) TKA’s were included in the study during their three month training period. A total of 30 patients were included in the study. The accuracy of conventional jig positioning was assessed simultaneously using navigation equipment. After this assessment, the actual bony resection was performed using CAN equipment.
There was a consistent trend towards improved accuracy between the early and late groups in the majority of parameters assessed. In the early group, the coronal plane tibial alignment was found to be outside the acceptable three degree range in 11 out of 15. In the late group this improved to two out of 15 (p< 0.05). An average of 2.8 degrees of tibial jig deviation during pinning was noted in the early group which improved to one degree in late group. The accuracy of jig placement in both groups was improved by CAN.
Computer assisted navigation is helpful in improving the accuracy of trainee surgeons and should prove a useful adjunct in training. Surgical accuracy using conventional jig based systems can be improved with training. Deviation of conventional tibial alignment jig during pinning is a significant factor. This aspect has not been appreciated fully in the past and can be minimised by the use of the navigation equipment. As shown in previous studies, the overall alignment using CAN is superior to what would have been obtained using conventional jigs for TKA.
Though the perceived advantages of computer assisted orthopaedic systems (CAOS) have been claimed incessantly over the years, these systems are far from commonplace in most orthopaedic theatres. Here, we present a summary of those very reasons.
Health Technology Assessment report elicited no proof of clinical benefits of the Robodoc over conventional procedures. Mazoochian et al were unable to confirm the same accuracy of implant position while using the Caspar. Honl et al found a higher revision and dislocation rate accompanied with longer surgery durations when robotic assisted technology was used.
Shortcomings identified in the CT-based navigation systems included an additional CT scan, which represents extra costs for the acquisition as well as additional radiation to the patient. Sistan et al claims that image-free navigational systems in knee arthroplasty do not provide a more reliable means for rotational alignment as compared to traditional techniques. Computer assisted pedicle screw insertion in the spine has also not demonstrated any significant clinical advantages.
To date, long term results of computer-guided or robot-assisted implantation of endoprosthetic devices are still lacking. With the unproven long-term clinical and functional results of patients who had computer aided surgery and given the multi-factorial complexities of patient outcome, it is difficult to claim via small scale short term studies that these systems present a significant benefit to the patient or the healthcare providers. Potential benefits of long-term outcome, better implant survival and functional improvement require further investigation and until that information is available this technology must be further developed before its widespread usage can be justified.
Surgical treatment of pelvic injuries is one of the most challenging tasks in trauma surgery. Intra-operative two-dimensional imaging technology can often not cope with the complex requirements of the three-dimensional anatomy of the pelvis. A registration, which is difficult to achieve with minimal invasive techniques, is obligatory for the CT-based navigation. Changes in the reduction can only be visualized inadequately. The intra-operative imaging after completed osteosynthesis has significantly enhanced since the introduction of three-dimensional image amplifiers. The three-dimensional data can be used directly for the visualization of the osteosynthesis material by linking it to a navigation system.
Since January 2001 the Trauma Center Ludwig-shafen has the ability to perform the registration-free three-dimensional navigation by linking the 3D image intensifier to a navigation system. From January 2002 to January 2005 30 patients with a pelvic injury, where the intra-operative navigation was carried out with the 3D image intensifier, were included in a prospective study. A complete neurological status, conventional fluoroscopic diagnosis, and CT-images were available pre-operatively for all patients. This information formed the basis for the classification and indication for surgery. Patients were positioned on a metal-free carbon table. Due to the registration-free navigation, and thus without the need for a manual registration of landmarks, a tissue-saving preparation could be performed. The postoperative assessment of the implant position was carried out by an independent radiologist.
Screw placement on the pelvic ring was performed in 23 patients (IS lag screws), in 3 patients on both sides. Periacetabular screws were implanted in 7 patients with acetabular fractures. A prerequisite was that the closed repositioning and a temporary fixation could be carried out before the recording of the 3D dataset. 7 surgeons participated in this study. The 3D image intensifier and the navigation system were always operated by the same person. In total 66 screws were implanted (49 IS screws, 17 periacetabular screws). One misplacement of a IS screw with a penetration of the neuroforamen was found during post-operative check-ups. The screw position was corrected during revision surgery. The mean fluoroscopy time for the recording of the 3D scans and the 2D check-ups was 1.78 (+/− 0.4) min. The mean operating time was 105 (+/− 24) min.
This prospective study demonstrated the clinical use of navigation in a three-dimensional dataset from the 3D image intensifier with automatic registration on the pelvis. A relatively high misplacement ratio during IS lag screw placement in the traditional, percutaneous technique according to Matta up to 30% is described in literature. The 3D image intensifier navigation facilitates a standardized working process in the operating room. This is reflected in the low range in fluoroscopy and operating time. The limiting factor in pelvic surgery is the relatively small image volume of the 3D image intensifier of 12 cm3 and the low image quality compared to a CT.
Anatomic reduction and appropriate implant placement is essential for optimal treatment of intraarticular tibial plateau fractures. Standard intraoperative fluoroscopy provides limited visualization of the reduction and hardware placement compared with pre- or postoperative 3-D imaging modalities. As such, post-operative computer tomography (CT) has become a common procedure to evaluate the quality of the reduction and fixation. The Iso-C3D provides 3-D intraoperatively imaging to dynamically assess the surgical reduction and fixation at different anatomic regions. We report on our first 19 clinical tibial plateau fractures scanned intra-operatively with the Iso-C 3D.
Between January and November 2003, 19 intraarticular tibia plateau fractures were scanned intraoperatively with the Iso-C3D (Siemens, Germany). No formal selection criteria were utilised except for the presence of a tibial plateau fracture. Operative procedures included 14 cases of open reduction internal fixation and 5 cases of internal fixation with arthroscopic assisted reduction.
Imaging Technique: All patients were positioned on full-carbon tables for the operative procedure. After initial operative reduction and fixation, conventional two-dimensional fluoroscopic imaging was performed using standard AP and lateral projections. These images were evaluated by the operating surgeon; if the reduction and fixation was judged to be appropriate, Iso-C3D imaging was initiated
In 21% (n=4) of all cases an immediate revision of the operative procedure was performed after Iso-C3D imaging. These revisions were not deemed necessary with conventional fluoroscopy alone. In two cases, significant intra-articular incongruencies (greater than two millimetres) were noted. Additionally, in two cases, implant mal-position was detected. All patients had a postoperative CT scan. All CT scans confirmed the intraoperative Iso-C imaging, no further additional articular incongruencies or malpositioned implants were identified. When compared to conventional C-arm images, the Iso-C 3D scans demonstrated improved ability to identify the articular malreduction and implant mal-position in all cases.
We have demonstrated that the Iso-C3D provides reliable intraoperative evaluation of reduction and hardware placement compared to traditional CT scans for tibial plateau fractures. In addition, clinically relevant intra-operative information was gained with its use in this study. In four (21%) cases, the operative treatment was modified due to the use of the multiplanar imaging modality. On average, 10 minutes of additional operative time was required for the use of Iso-C3D scanning and the evaluation of the images. Further prospective clinical studies are needed to improve our findings.
Computer aided joint replacement surgery is being used increasingly. It is more commonly used at present in the knee replacement surgery as compared to hip replacement arthroplasty. It is still under developmental phase. The published literature shows there is increased accuracy of the component placement of acetabular cup and femoral stem. We describe the technique for the Stryker navigation system as used in total hip arthroplasty.
The technique used by us presently is an active tracker system. This is a both way communication system of infrared waves between the trackers and the sensors. The trackers are fixed to the bones, then the registration of patient specific anatomy is done and hip arthroplasty is performed with aid of the computer navigation.
The computer navigation gives the values of the component orientation in space. It gives the implant position in the pelvis and femur models generated by the computer but fed in and created by the surgeon. It is important that the data fed to the computer in making the model of pelvis and femur is accurate. It is surgeon dependent. At the end of surgery one can also evaluate impingement and range of motion. It also shows the change in offset of the centre of rotation of the hip as well as leg lengthening. While it can aid in the technical performance it is essential that the surgeon does not go blind to his operating environment as the computer navigation is to help the surgeon, not replace.
Hip resurfacing is a challenging task. Not only because of the historic failure of the early resurfacings, like the Wagner cup, that mainly failed due to deficits in technology. But two other issues make resurfacing such a difficult undertaking: the femoral head and neck are not removed, which makes access to the acetabulum more difficult.
There are two critical steps during hip resurfacing that call for utmost precision: the placement of the central guiding rod in the femoral head and neck and the orientation of the cup. The central head/neck rod is crucial for the success of the surgery: it decides upon the alignment of the femoral component and whether any impingement with the femoral neck occurs or not. Initially this rod was introduced in a retrograde fashion from the lateral side, using a jig similar to those used during arthroscopic k-wire placement. This worked well and safely, yet required a large extension of the incision, which seems unacceptable in these minimal invasive days. The new jig allows for smaller incisions and seems to be working well, but still requires a lot of talent and/or training on behalf of the surgeon, and certainly is not fail safe. It is rather based on trial and error. Simple computer navigated placement of the central rod is feasible, cheap and fast, and it will guarantee precision in every case.
The same goes for cup placement. As the method requires a rather big cup, there is not much room for correction once the acetabulum is reamed. The very enlightening publications from Tony DiGioia and Branko Jaramaz have shown the susceptibility for error during cup reaming and placement. Adaptation of the existing navigation systems for the purposes of hip resurfacing is simple and fast. One should not hesitate to incorporate this extra quantum of security for the sake of the patients, for the sake of the method and, last but not least, for the sake of the surgeons.
This paper presents initial results of the Acrobot® Navigation System for Minimally Invasive (MI) Hip Resurfacing (HR) which addresses the problems of conventional HR. The system allows true MI HR – mini-mising the incision and tissue retraction required, and conservation of bone in contrast to other MI total hip procedures.
Pre-operative CT-based software allows the surgeon to plan the operation accurately. Use of CT gives the greatest accuracy, and is the only method which can give an accurate assessment of procedure outcome (planned versus achieved implant position). Intra-operatively, the bones are registered by touching points using a probe connected to a digitising arm. Next a series of tools is connected so that bone preparation and implant insertion is performed using on-screen guidance.
The accuracy of the registration probe is within 0.6mm, inside the acceptable margin for optical tracker systems. We have validated this acceptability using registration simulations leading to a protocol which restricts registration errors to within 1.5mm and three degree. These error margins are within those in the literature for acetabular component placement using optical tracker based systems (five degree inclination, six degree anteversion). No comparable data could be found regarding the accuracy of femoral component placement during computer-assisted HR.
The system is currently undergoing clinical tests at one alpha site, with three further beta sites planned for early 2006. The methods described by Henckel et al (CAOS International Proceedings 1994, pp. 281–282) are being used to evaluate the performance of the system, comparing pre-operative to post-operative CTs to obtain a true, accurate measure of performance.
This paper illustrates the concept of a versatile surgical assistance system which combines an optical navigation system and a robotic arm. The integrated system offers precise positioning and guiding of surgical instruments according to pre-operative planning. A unique feature results from its capability to track small motions of the patient in real time, eliminating the need to rigidly fix the anatomical structure to be operated. The modular system architecture facilitates the adaptation of a common basic hardware platform to various surgical applications by adding associated software modules as well as appropriate surgical tools mounted to the robotic arm. The arm can be regarded as a controlled machine actuator of a navigation system. Its operation is mainly controlled by interactive operating modes which are based on a versatile haptic interface. The system supports the surgeon in those parts of a procedure where human skills are limited, but always lets him take full control, for example by directly grasping and moving the arm at its wrist if he wants to push the arm aside.
Hip resurfacing has advantages over hip replacement for younger, more active patients. However, it requires that surgeons learn new techniques for correctly cutting bone and positioning the components. Pre-operative planning systems exist for conventional hip replacement. Planning software for hip resurfacing is described, with the resulting plans available as a visual aid during surgery, or transferred to the Acrobot® Navigation system for intra-operative guidance.
CT data is acquired from the top of the pelvis to immediately above the acetabulae in 4 mm slices, and from there down to just below the lesser trochanter in one mm slices. This keeps radiation doses low while providing high image quality in the important regions for planning. This is segmented semi-automatically, and bone surface models are generated.
Frames of reference are generated for the pelvis and femur, and the acetabular and femoral head positions are computed relative to these.
Prosthesis components are initially positioned and sized to match the computed anatomy. They can then be adjusted as required by the surgeon. While adjusting their positions, he is able to visualize their fit onto the bone to ensure good placement without problems such as femoral neck notching.
Twenty one hip resurfacings have been planned including two navigated cases. In addition, visualization of hip geometry for osteotomy and impingement debridement has been performed on 14 cases, giving the surgeon a good understanding of hip geometry prior to surgery. Initial evidence indicates surgeons find the planner useful, particularly when the anatomy is not straightforward.
The use of computer aided joint replacement surgery is increasing exponentially. Its use in hip arthroplasty is still under developmental phase. Although the available literature shows there is increased accuracy of the component placement but there can be a number of factors on which it relies.
We have used the Stryker navigation system to aid in total hip arthroplasty for more than four years. It is improving continuously with time. Still there are many factors which are completely surgeon dependent and which can cause lot of variations in the component placement. Most important factors are the registration of patient anatomy and fixity and immobility of the bone trackers during the procedure. A number of other simple things can produce errors. We carried out some studies to see the effect on navigation values which will be presented. While use of computer navigation can aid greatly in achieving the set goals, it is dependent on surgeon thought process and appropriate implementation of the procedure.
Modern hip-replacement requires fixation of the femoral component, the stem, in the proximal femur. After resection of head and neck, the surgeons prepare the shaft in order to make room for the stem. Cemented fixation of the stem requires over-reaming, because the surgeon needs to provide space for the cement mantle, usually between 2 and 4 mms wide. Reaming for cemented fixation means removal of (cancellous) bone stock. Precision of reaming is not of utmost importance, as cement will fill gaps and will provide close contact between implant and bone. Cementless fixation on the other hand requires rather precise reaming, as for the biological fixation to occur, a close contact between implant and bone is crucial. There are two ways to achieve such contact: ream the bone to the precise negative form of the implant, or compress the cancellous bone into this shape. Compressing is technically easier and is regarded by some as the better option: the supposedly weak cancellous bone is compressed and provides a firm contact surface for the implant. The other option is precise reaming of the surface, sparing the scaffolding of the cancellous bone to provide biological support for the implant. It is difficult though to achieve this precise cutting with traditional tools: an animal experiment conducted by the author showed fractured and destroyed bone in the hand broached group, resulting in defects and lasting atrophy in the periphery, due to inadequate load transfer. These results coincide with a cadaver study performed by v.Hasselbach et al in 1996. The alternative to traditional hand broaching in both studies was using a high speed cutter with 70,000 rpm. As such a cutter can not be applied by hand due to the high torque; surgery was performed in both studies using a robot guiding the cutter. Cuts were performed according to a preoperatively established plan.
In the animal experiment, histological examination after one year showed no signs of atrophy in the high speed cutter group, whilst atrophy was still present in the hand broached group. These results coincide with significantly better performance in the postoperative force plating.
Conclusion: Application of navigation systems has helped to solve the problems in orientation of both cup and stem. Yet the preparation of the interface of the stem remains an unaddressed issue both in navigated and minimal invasive surgery. The use of high speed cutters (which prove to be helpful also in total knee replacement – Acrobot and Robodoc) seems an option that should not be neglected. The interface between bone and implant is the location where the fate of the implant is decided.
The use of navigation systems to aid in the performance of total knee replacement has become an accepted method of treatment. Previous studies have shown that by using computer aided navigation the components can be implanted with more reproducible accuracy.
We present the results of a prospective randomised trial, with ethical committee approval that was performed to compare the use of a new, two-pin system with the original three-pin system to fix the tracker to bone. There were 37 patients in the two-pin group and 31 patients in the three-pin group. Pre-operative demographic data was similar. Patients were assessed pre and post operatively clinically using the Knee Society Score, WOMAC and SF36. Radiographic assessment was performed using “The Perth CT Protocol.”
At one year there was no significant difference clinically between either group. Radiographic assessment showed no significant difference in the results of all the prosthesis variables as measured by the Perth CT Protocol, except in the femoral prosthesis absolute varus/ valgus position, with the two-pin group being more accurate. The upgraded tracker fixing system in the computer navigation system allows as accurate implantation as the earlier system with less patient morbidity.
Computer aided joint replacement surgery is being used increasingly. It has found its most common use in the total knee replacement arthroplasty. Although the literature has proven its accuracy in the alignment of the components, we still await the long term benefits in terms of patient outcome and longevity of the prosthesis.
The parameters of the alignment are created and fed to the computers, although most of these are based on long term wisdom and on the historical observations rather than on hard scientific studies as to the ideal positioning of the implants for each specific individual. It is therefore important that while using the computer guidance we understand what are the technical assumptions and points based on which the computer is guiding us. A presentation of these will be done mainly based on Stryker knee navigation system.
The first generation of surgical robots which has been used in orthopaedics was characterized by automatic performance of certain tasks like milling of bone cavities or planes. These systems have not been successful as their application and operation suffered from a number of unacceptable drawbacks. Presently computer assisted surgery is dominated by surgical navigation systems where position and orientation of manually guided instruments are visualized on a computer screen as an overlay to the picture of the anatomical structure.
However, new concepts of surgical robots make the benefits of using robotic systems more evident. Such robots do not operate automatically but are designed as assistance systems which support the surgeon by interactive operating modes. Compared to manual instrument guidance in pure navigation they offer several additional advantages some of which are particularly valuable to support less or minimal invasive operating techniques. No problems due to tremor or unintentional slipping of the tool. Precise drilling or reaming by stable tool guidance, surgery will be exact and reproducible to achieve pre-operatively planned targets, to overcome the ergonomic problems, such as difficult hand-eye-coordination and frequent changes of viewing direction. The application of interactive assistance robots in orthopaedic and trauma surgery is illustrated by describing exemplary procedures.
The primary objective of navigation systems is to optimise component alignment to improve total knee replacement (TKR) performance. This study utilizes finite element analysis techniques to determine how component alignment affects tibial insert contact stresses. Contact stresses were derived from navigation system and conventional TKR alignments, and were compared to ideally aligned components.
This study builds upon the work of a previous study, in which post-operative CT scans from 70 patients were utilized to extract knee component angular alignments. These patients had been randomised to having either navigation based or conventional TKR.
Knee component finite element models were oriented into specific alignment positions. Tibial insert contact stresses were computed under physiologically relevant loads at various flexion angles. Finite element analysis was also performed on ideally aligned cases for comparison purposes.
At full extension, the median alignment of conventional TKR induces contact stresses 17.8% above ideal alignment conditions. Navigation based TKR alignment induces stresses 3.5% above ideal alignment conditions. At 45–90° flexion, conventional TKR alignment induces stresses 2.7% above ideal alignment conditions, while comparable navigation based TKR alignment induces stresses that match ideal alignment conditions.
Knee component alignment is improved by navigation techniques. This predictive finite element analysis study shows markedly reduced contact stresses for navigation aligned TKR compared to conventional aligned technique. The reduction in tibial insert contact pressures could reduce abnormal polyethylene wear, increasing the structural longevity of knee system components.
Minimally invasive total knee arthroplasty is growing in popularity. It appears to reduce blood loss, reduce hospital stay, improve post-operative quadriceps function and shortens post-operative recovery. We show our experience of minimally invasive TKA with a computer navigation system.
Forty patients who underwent MICATKA were compared with forty patients having conventional CATKA. Component positioning was assessed radiographically with AP long leg standing views. Knee Society Scores, length of stay and recovery of straight leg raise was also recorded pre-operatively and at 6, 12, 18 and 24 months.
Pre-operative Knee Society Scores showed no significant difference between the two groups. Post operatively the mean femoral component alignment was 89.7 degrees for MICATKA and 90.2 for CATKA. The mean tibial component alignment was 89.7 degrees for both. Knees society scores at 6, 12, 18 and 24 months were statistically better in the MICATKA (p< 000.1). However the mean difference in Knee Society Scores had fallen. Straight leg raise was achieved by day one in 93% of the MICATKA compared to only 30% of the CATKA. Length of stay for MICATKA was a mean of 3.25 days with CATKA a mean of 6 days.
MICATKA is a safe procedure with reproducible results. Alignment is equivalent to CATKA. It gives statistically significant improvement in Knee Society Scores compared to the open procedure. The length of stay and time to straight leg raise is also reduced. At a minimum of 2 years follow-up we have seen no revisions and no evidence of radiographic loosening. A randomised multi centre trial is under way and early results are awaited.
Accurately planning the intervention and precisely measuring outcome in computer assisted orthopaedic surgery (CAOS) is essential for it permits robust analysis of the efficacy of these systems.
We demonstrate the use of low dose computer tomography (CT) radiation for both the planning and outcome measurement of robotic and conventionally performed knee arthroplasty.
Studies were initially performed on a human phantom pelvis and lower limb. The mAs (milliampere seconds) were varied from 120 to 75 at the pelvis and from 100 to 45 for both the knee and ankle whilst keeping the kV (kilovolt) between 120 and 140. Image quality was evaluated at the different doses.
The volumes scanned were defined on the scout film; they included the whole femoral head (0.5cm above and below the head), 20cm at the knee (10cm on either side of the joint line) and 5cm at the ankle (the distal tibia and the talus). Effective dose (mSv) was calculated using two commercially available software packages. This protocol was subsequently used to image patients in our prospective double-blind randomised controlled study of our active constraint robotic system ACRO-BOT.
With the reduction in the mA and scanned volume the effective dose was reduced to 0.761 mSv in females and 0.497 mSv in males whilst maintaining a sufficient image resolution for our purposes. We found that a mAs of 80 for the hip joint, 100 for the knee and 45 for the ankle was sufficient for imaging in both pre-op planning and pos-operative assessment in knee arthroplasty. This contributed on an average effective dose to the hip of 0.61 mSv, the knee 0.120 mSv and to the ankle 0.0046 mSv.
The results of our study show that we have considerably reduced the effective dose (0.8 mSv) to one third of the Perth Protocol (2.5mSv) by reducing the areas of the body scanned and adjusting the mA for the various parts of the body whist maintaining the x, y and z axis throughout the scan. The areas between the knee, hip and ankle that were not exposed to radiation are not strictly necessary for the planning of knee arthroplasty, but it is essential that the leg does not move during the scanning process. In order to prevent this leg was placed in a radiolucent splint. For post op three dimensional (3D) assessments only the knee component of the protocol is necessary.
Revision total knee replacement is becoming a more common procedure. Landmarks commonly used for alignment are often distorted by the cause of the failure or removing the components themselves. This can make correct alignment and re-creation of joint line height difficult.
We looked at consecutive knee replacements that underwent revision surgery over one year. All cases had revision total knee replacements by the senior author using the Stryker® Navigation System. All cases were assessed radiographically post-operatively with long leg Maquet views. The tibial and femoral component varus/ valgus angles taken from the mechanical axis and the mechanical tibio-femoral angle were measured.
On long leg Maquet views the mean mechanical tibio-femoral angle was 3.25 with a range from 0 to 6, the mean tibial component angle was 90.4 with a range of 89 to 92 and the mean femoral component angle was 90.3 with a range of 89 to 91.
Computer navigation in revision total knee replacement is a safe procedure that gives reproducible results. Postoperative alignment, as measured radiographically, gave good results with tibial and femoral components within 2 degrees to the perpendicular of the mechanical axis. We feel that navigation is helpful in obtaining accurate positioning of components in revision knee surgery.
Revision total knee arthroplasty (TKA) is becoming a more frequent procedure throughout Europe. Painful patello-femoral problems, patellar dislocation, impingement pain as well as aseptic loosening and gross malalignment are among many causes. We investigated the use of CT scans in identifying alignment causes for pain in failed TKA where no other obvious cause is found.
Twenty poorly functioning TKA were analysed using the Perth CT protocol. All patients were awaiting revision TKA and had no obvious evidence of infection or loosening. They were scanned using a GE multislice CT scanner. The measurements were performed using standard CT software. Knee society scores were obtained pre- and post-operatively.
The mean coronal position of the components was three degrees of valgus for the femoral component and 2.5 degrees of varus for the tibial component. Fourteen knees had errors of femoral component rotation, which ranged from one degree of external rotation to nine degrees of internal rotation. The cumulative error of implantation ranged from 6–24 degrees in all planes. Knee society scores improved post-operatively from a mean of 52 pre-operatively to 83 at one year. Compound error also improved to a range of 6 to 10 degrees in all planes.
Revision TKA remains a difficult procedure that is increasing in frequency. The use of a CT protocol allows all coronal, sagital and rotational errors of an implant to be accurately identified prior to surgery. This could be useful in the small groups of patients with painful TKA that have no obvious cause for failure. Total knee replacement failure in these cases maybe explained by a cumulative error in alignment and correction of which may improve their Knee Society Scores.
We believe that a CT scan of a failed TKA is useful as part of the pre operative planning and also in investigating painful TKA where no obvious cause is found.
The primary objective of this study was to evaluate the performance of the Acrobot® Sculptor system in achieving a surgical plan for implantation of unicompartmental knee prostheses, compared with conventional surgery. The Acrobot® Sculptor is a novel hands-on medical device, consisting of a high speed cutter mounted on a robotic device which the surgeon holds and directs.
A prospective, randomised, double-blind (patient and evaluator), controlled versus conventional surgery study was undertaken and has been fully reported in Journal of Bone and Joint Surgery (British), 88-B.
All (13 out of 13) of the Acrobot® cases were implanted with tibio-femoral alignment in the coronal plane within ±2° of the planned position, while only 40% (six out of 15) of the conventionally performed cases achieved this level of accuracy.
There was also a significant enhancement in the extent of post-operative improvement, as measured by American Knee Society (AKS) Scores at six weeks, in the cases implanted with the Acrobot®. The difference between type of surgery is statistically significant (p=0.004, Mann-Whitney U test). Operating time (skin to skin) is higher in Acrobot treated subjects, but the difference between the two types of surgery fails to reach significance.
The Acrobot® System was found to significantly improve both accuracy and short term outcome in this investigation. By permitting the creation of bone surfaces that can be machined by means other than an oscillating saw, the Acrobot® System paves the way for novel implant designs to be developed, facilitating bone conserving arthroplasty in the knee, hip and spine with a new generation of even less invasive but more reliable procedures.
We studied the change in the axial rotation of the tibia at different levels of knee flexion after Knee Replacement using navigation systems.
We reviewed the knee kinematic data of 36 consecutive patients (15 males and 21 females) who underwent elective knee replacement (Scorpio/Stryker) at King’s College Hospital. All data were generated using the navigation TKR trackers and software of a knee replacement system. All preoperative data obtained before any soft tissue release. We studied the tibial rotation at 30°, 60° and 90° of knee flexion. All operations were performed by consultant orthopaedic surgeons. We used the Wilcoxon non parametric two sample test for statistical analysis.
The average tibial internal rotation upon knee flexion was 9.4° preoperatively and was reduced to 5.3° (mean 7.3°) post operatively. Most of the change (80%) occurred within the first 30° of flexion (p< 0.001). Postoperatively 38% of the studied knees had the screw home mechanism preserved. 52.7% had a mixed pattern of both internal and external rotation of the tibia and three knees (8%) had a reversed rotation of the tibia. The abnormal screw home pattern was preserved in 16 of the postoperative joints (46%). One knee was found postoperatively with external tibial rotation in all flexion increments. The abnormal pattern of tibial rotation was not improved following a navigation arthroplasty.
We found that computer navigated TKR reduces significantly the tibial rotation and the replaced knee joint does not behave as a hinge joint. Pre-existing abnormal tibial rotation patterns were not improved postoperatively.
Although total knee replacement (TKR) has good long term reliability, some patients remain unhappy; this may relate to abnormal motion causing pain or instability. This study measured the effect of TKR femoral component internal-external rotation position upon knee kinematics.
The kinematics of eight fresh-frozen cadaveric legs were measured, with a range of loading and states of preparation. The stages of preparation included intact; TKR in standard navigated position aligned to mechanical and epicondylar axes, TKR with three and six degree internal and then external rotation of femoral component. The loads applied were 70N anterior and posterior draw; Five Nm internal and external rotation; Five Nm valgus and varus. All these were applied in every state of preparation with the knee moved passively in 0–120deg flexion-extension, then repeated with the quadriceps tensed to 400N by a pneumatic cylinder and cable. The TKR used was a Stryker Scorpio posterior cruciate retaining. The implant positions and tibio-femoral kinematics were measured continuously using a modified software Stryker knee navigation system, leading to ′envelopes of laxity′ for each degree of freedom across the range of flexion-extension. In order to vary the implant rotation, the ‘standard’ TKR was removed and then remounted on an adjustable intra-medullary rod-intube mechanism that was also linked to the navigation system. Adjustments in 6 degrees of freedom allowed the datum position to be regained within 1mm and 1deg, using a custom software module and a sensor located on the implant.
Internal rotation of the femoral component caused increasing tibial valgus with knee flexion, with the increase in valgus at 90deg matching the changed rotation. Similarly, external component rotation caused matching tibial varus with knee flexion. Varus and valgus laxities were not altered significantly from those in the datum condition by femoral component internal rotation, across the whole range of flexion. However, external rotation caused increased valgus laxity in flexion. Tibial rotational effects were complex. In the extended knee, femoral component rotation caused a matching tibial rotation. Thus, an externally rotated femoral implant magnified tibial external rotation (the screw-home) with terminal knee extension. The tibial internal rotation with knee flexion was then increased above normal, so that the tibia was internally rotated at 90deg flexion. Internal rotation of the component caused increased internal rotation laxity and decreased external rotation laxity; the opposite occurred after femoral component external rotation.
Changes in femoral component position had complex effects on the movement and posture of the tibia across the range of knee flexion. Some have easily-understood consequences, such as component internal rotation caused tibial valgus in flexion, thus increasing the lateral force vector acting on the patella. The changes in rotational laxity patterns are related to the differing structures of the medial and lateral collateral ligament complexes, the lateral collateral ligament allowing greater freedom of movement in response to the altered height of the ligament attachment above the joint line at that side of the knee, whereas the medial collateral ligament maintained greater control of rotational laxity. These effects explain loss of stability in flexion and the tendency of the knee to pivot about a medial axis.
We used computer tomography (CT) to measure the outcome of knee-arthroplasty in our prospective double-blind randomised controlled study of our active constraint robotic system ACROBOT.
All patients in our trial had pre-operative CT scan and proprietary software used to plan the size, position and orientation of the implants. Post operatively a further CT scan was performed and measurement studies performed using 3 different methods of manipulating the CT dicom data.
Method 1, a quick and simple method of implant assessment that measures the varus-valgus orientation of the implants relative to the axes of the long bones
Two landmarks each are used to define the individual mechanical axis for both the femur and tibia, for consistency these landmarks are the very ones used in the planning stage on the pre-operative CT.
Landmarks are then placed on the implants in order to measure their tilt relative to the mechanical axes. An appropriate Hounsfield threshold (2800) was used to image the metal components. The angle between the individual mechanical axis and the prosthetic component was calculated.
Method 2, detailed and accurate comparisons between the planned and achieved component positions in 3D are made. Co-registration of the precisely planned CT based models with surface models from the post-op scan gives real measurements of implant position enabling the measurement of the accuracy of component in an all six degrees of freedom giving both translation and rotation errors in all three planes.
The process of alignment was achieved by surface-to-surface registration. An implementation of the iterative closest point algorithm was used to register matching surfaces on the objects to be registered. A polygon mesh of the implant, provided by the manufacturer, defined the surface shape of each size of implant. This was used both to define the planned position and to register to the post-operative scan. Method 3, in this study we quantified post-operative error in knee arthroplasty using one value for each component whilst retaining 3D perspective.
The position of the prosthetic components in the post-op scan is calculated and individual transformation matrix computed which is matched to the transformation matrices for the planned components.
The pre-operative CT based component positions were co-registered to the post-operative CT scan and values for the intersection (volumetric) between the digitised images (both planned and achieved) were calculated. Both the co-registered femoral and tibial component’s intersection was quantified with software packages supporting Boolean volume analysis
Method 1, the sum of the two, independently measured, angles allows an estimate of the post-operative alignment of the load bearing axes in the two bones.
Method 2, 3D CT allows precise measurements of the achieved position for each component in all three planes. Six values, three angular and three translational, define the achieved component position relative to the planned position.
Method 3, the greater the percentage intersection between the planned and achieved images, the greater the accuracy of the surgery. Owing to the shape of the components (large articular surface) large intersections demonstrate more accurate reconstruction of the joint line.
In the recent past the lack of a sufficiently accurate tool to plan and measure the accuracy of component placement has resulted in an inability to detect and study radiological and functional outliers and hence the hypnotised relationship between prosthetic joint placement and outcome has been difficult to prove.
CT offers us the ability to accurately describe the actual position and deviation from plan of component placement in knee arthroplasty. Whilst X-ray has the intrinsic problems of perspective distortion magnification errors and orientation uncertainties CT can be used to define ‘true’ planes for two dimensional (2D) measurements and permits the comparison in three dimensions (3D) between the planned and achieved component positions.
Tibial rotation and translation provide important stability parameters after ACL reconstruction. An accurate tool for a combined pre- intra- and postoperative stability measurement is not in clinical use so far. Navigation of the drill canals for the ACL placement and evaluation of possible impingement problems has been introduced for some years already, while measurement of the tibial translation and rotation is only available for a short time and only available for a few navigation modules. Navigation provides an accuracy of 1mm/1°, therefore navigated measurement of tibial rotation and translation were evaluated in this study with a new developed mechanical device and directly compared to conventional measurement techniques.
Accuracy of navigation was compared with the KT1000 for the anterior-posterior (AP) translation and to a new developed goniometer tool concerning the rotational range of motion. Comparative tests included plastic whole leg models and specimens. Tests were repeated with intact and dissected ACL′s. A conventional navigation system (Vector Vision, Brainlab, Germany) was used in all cases. This included software developed for fluoroscopy based navigated ACL reconstruction. The following knee kinematics were detectable with the navigation system: Flexion/Extension degrees of the knee joint (°); AP translation of the tibia in relation to the femur (mm); Axial tibial rotation relative to the femur (°).
Validation of Navigation: first neutral tibial rotation was defined and marked in the knee joint in neutral position. All rotational measurements were done with a new developed goniometer tool and compared to the navigated technique. Then the knee was rotated externally until 45° (maximum) and internally 45° (maximum), by single 2.5° steps. These measurements were repeated in 0°, 30°, 60° and 80° knee flexion. All tests were repeated three times and performed by 3 different observers. A total of 1296 measurements were done. Measurements of the tibial translation were compared with the KT 1000 for the specimen testing.
Results revealed: accurate navigated measurement of tibial rotation in plastic and specimen models; variation of absolute AP translation values between KT1000 and navigation; variation of the AP translation corresponding to the ACL condition; increased range of total tibial rotation after dissecting the ACL compared to the intact ligament.
Restoration of the rotational stability and limiting of the AP translation is necessary to provide normal knee kinematics after ACL reconstructions. Intraoperative measurements of these stability parameters are demanding and so far not established with navigation systems or conventionally. As our results show, navigation offers an accurate technique for measurement of the AP translation and rotation of the knee with intact and dissected ACL’s under laboratory conditions. General use in the evaluation of a successful ACL reconstruction becomes possible intraoperative and might be reproducible for further measurements. Clinical studies are needed to improve our results.
The degree of correction was controlled during the operation with the navigation system and compared with pre- and postoperative 2.5D ultrasound measurements to avoid projection errors of long standing x-rays.
The postoperative 2.5D ultrasound leg axis analysis showed a maximum of +/− 2° difference between the pre-, intra- and postoperative measurements.
This first results show a promising increase of accuracy while radiation can be reduced. The actual values show that the main goal to increase the intraoperative accuracy in corrective osteotomies can be achieved with computer aided surgery.
Optimal soft tissue tension maximises function after total knee arthroplasty (TKA). Excessive tension may lead to stiffness and or pain, while inadequate tension can lead to instability. Composite component thickness is a prime determinant of this soft tissue tension. The thickness provided by polyethylene inserts currently allows for a 2–3 mm incremental change. This study analyses the effect of incremental change in polyethyl-ene thickness on soft tissue tension.
Computer assisted (Stryker Knee Nav) TKA was performed on 8 cadaveric knee specimens (4 pairs). Kinematic data was collected through the navigation software. The soft tissue tension was analysed by measuring compartmental loads. A validated load cell instrumented tibial insert was used to measure medial and lateral compartmental loads independently. The effect of 1mm increments in polyethylene thickness on compartmental loads was evaluated.
We measured an increase in compartmental loads with increasing insert thickness. The peak loads in each compartment showed different behaviour reflecting varying tension in the medial and lateral sides. The peak loads generated showed a reduction after reaching a maximal level with further increase in insert thickness. With a one mm increase in insert thickness, 75 % of specimens showed greater than 200 % increase in the peak loads in the lateral compartment. Similarly the medial loads showed a greater than 100% increase. Individual specimens showed a high variability in loading patterns.
Our study highlights high variation of knee loads present between subjects. The compartmental loads vary as a function of insert thickness. The high sensitivity of compartmental loads with a 1mm increment is significant and has not been previously appreciated, especially intraoperatively. The currently available TKA inserts with 2–3 mm increments may make obtaining optimal soft tissue tension difficult. In addition to the current focus of obtaining accurate leg alignment, further computer aided techniques are required to address soft tissue tension.
There was a positive correlation between instrumented Cobb angle and total SRS-24 score (p=0.03, r2=0.085) and between curve correction and total SRS-24 score (p=0.04, r2=0.081). No correlation was found between coronal alignment, sagittal alignment, shoulder elevation or size of rib hump and the SRS-24 scores (p> 0.05).
Patients ranged in age from 18 years to 91 (average age 48 years) and 41% were males. Thirty percent of the population was deformity patients, 49% degenerative patients and the remaining 21% had various other spine problems. Thirty-five percent of the patients underwent a combined anterior posterior procedure, 13% anterior alone and 34% posterior alone.
Statistical analysis included descriptive summary, vicariate correlation to assess individual risk factors (university analysis) and multivariate regression.
Overall, 61% of the patients had at least one of the major risk factors. The number of major risk factors increased with increased age. The percent of patients with any given risk factor also increased with age.
When no other factors were taken into account (such as co-morbidities), there was an increased occurrence of a major complication (any one), pneumonia and infection with increased age at time of surgery. In order to differentiate the effect due to age and due to co-morbidities (which increased with age), multivariate regression was utilized. For the occurrence of any major complication, the presence of respiratory problems and previous infection were both more influential than age. Furthermore, when the effects of these two risk factors were controlled for, there no longer was an effect due to age.
The purpose of this project was to provide a systematic review of the literature on RF neurotomy for the treatment of spinal pain of zygapophysial joint origin.
The basis of back pain and disc degeneration is little understood. The end point of disk degeneration is cellular decline, loss of water content, decrease of proteoglycans, decrease in Type II collagen with consequent increase in Type I collagen as well as anular fissures, loss of mechanical competence of the disk facet complex as well as bony changes. Little is known of the process from the healthy disk to more degenerated disc.
The current solution to what is thought to be the causes of the problem is surgery involving disc excision, fusion and/or replacement. These solutions may be the cause of more problems. Frequently these solutions are temporary. The question is whether there is a better or different way to treat this pain-generating disc degeneration. In intervening with disc degeneration by manipulating the cellular environment, timing may be everything. However we do not know at which time point the decline of disc tissue becomes irreversible, when any cellular, genetic or growth factor therapies to try to regenerate will be futile. The goal is to find this point and try to perform therapies that are appropriate at that time point. The strategies should include promoting and upgrading matrix synthesis within the disc, inhibiting the catabolic processes that may be a normal aging process, and to try to replace the loss number of cells to increase the matrix to avoid the imbalance between synthesis and catabolism that maybe causing the disk degeneration.
Disc tissue and chondrocytes cultured using a variety of techniques synthesize proteoglycans and collagen type II. These culture systems can be used to manipulate the biology using growth factors, gene therapy methods and environmental cues to increase proteoglycans or collagen II production. Human OP-1 has been shown to increase proteoglycan synthesis while collagen type II can be increased when cultures are exposed to recombinant human BMP. Unfortunately, growth factors have a short half life and must therefore be administered in multiple doses to prolong their effect.
The potential solution may be the use of viral vector or gene therapy. When a viral vector with an exogenous gene is introduced into cell cultures, the gene is incorporated into the target cell which can express the gene producing growth factors long term. Adenoviral vector systems using a therapeutic gene containing TGF beta 1 promotes both proteoglycan and collagen synthesis. This response is dose dependent. Similarly, anulus fibrosis cell cultures show increased collagen synthesis when exposed to viral vectors carrying BMPs and Sox-9 genes. Combined use of multiple growth factors genes such as TGF beta 1, BMP 2, and IGF has an additive effect on proteoglycan synthesis. The Sox-9 gene is essential for chondrogenesis. It has been shown to promote type II collagen synthesis in disc cell cultures. In animal studies adeno Sox-9 inoculation of the disc maintains normal disc anatomy while controls show disc degeneration and osteophyte formation.
To date, studies show that growth factors may slow the degenerative process but not reverse it. Disc chondrocytes are sparse in numbers and difficult to isolate and culture. Mesenchymal stem cells grown in an hypoxic environment will produce collagen and Sox-9 markers similar to nucleus pulposus cells. Cells harvested from the disc and grown in culture will survive and synthesis matrix when retransplanted into the disc environment. If suitable cells can be cultured and genetically manipulated to up regulate growth factor production, then introduction of these cells into a degenerating disc at an appropriate stage might favorably moderate the degenerative process hopefully obviating the need for surgery.
MRI experiments were undertaken at 25.0 ± 0.1 °C on a Bruker Avance NMR spectrometer (Bruker Bio-Spin, Rheinstetten, Germany) using a 7.0T vertical bore magnet system, equipped with a 1.1 T m-1 (110 G cm-1) gradient set and 15 mm ‘birdcage’ RF resonator. Specimens for testing were immersed in physiological saline inside a 15 mm NMR. Both multi echo and diffusion weighted images were acquired with a recycle time TR = 2 s and 8 averages using a 0.7 mm slice thickness, a field of view (FOV) of ca. 15 × 15 mm and a 128 × 128 matrix. For multi echo experiments the echo time was 5 ms with 64 echoes and for DT imaging a diffusion gradient duration δ = 2 ms and diffusion delay Δ = 12 ms. The diffusion tensor was calculated from the seven requisite diffusion-weighted images using in-house Matlab® code (The Mathworks, Natick, MA) written for the purpose.
access to remove the fragment posteriorly is severely compromised by the condition. The commonest spinal deformity requiring surgery in the achondroplastic is thoracolumbar kyphosis, the tendency to which is increased by a posterior approach.
A 46-year old male fell down stairs sustaining a neck injury and loss of consciousness. A CT scan of his cervical spine demonstrated an odontoid peg fracture (type II). Subsequent imaging showed the odontoid peg was completely normal. The initial CT appearances were entirely due to artifact caused by the patients’ tongue piercing!
The aim of this series of experiments was to measure the temperatures reached during VP using a sheep model. The cement volume effect and inter cement differences were assessed. Spinal cord monitoring was undertaken to monitor spinal cord function during this procedure to validate this for clinical use.
Spinal cord monitoring showed that when PMMA was injected into the correct location within the vertebral body there was no change in amplitude of the evoked potentials. When significant leakage of PMMA occurred, there was a decrease in amplitude of MEP’s.
Using epidural monitoring we were able to show that when PMMA is injected into the correct location within the vertebral body there is no change in amplitude of MEP’s.
We describe the technique of utilizing the Trimline™ Vertebral Body Distractor in correction of the sagittal plane deformity and maximizing the contact surface between plate and fusion construct
The compressive strength of the MAA and MSA based copolymers was measured as a function of anhydride concentration. Compressive strength for MMA increased (90±9 to 140±10 Mpa) in an approximately linear manner for MAA concentrations from 10 to 40 wt.% but decreased markedly for MAA concentration of 45% (62±14 Mpa). The compressive strength of MSA decreased exponentially for concentrations ranging from 10 to 45 wt.% (140±18 to 39±1 Mpa).
Autograft – Since before modern surgical techniques were described, ancient Greeks new of the possibilities for bone to grow after fracture. Studying open fractures, often post mortem, they new of the importance of both the “amount and integrity of bone architecture” that was necessary for two ends of a bone to heal. More recently, modern spinal surgical techniques, many pioneered by surgeons such as John Moe MD, use the same knowledge that for the intentional arthrodesis of two or more bony spinal levels there requires a certain amount and quality of bone – both capturing osteoinductive and osteoconductive properties.
Autograft can be harvested in many ways for spinal arthrodesis and can be taken from iliac crest, tibia or fibula, and from local vertebral sources. Often requiring a separate skin and/or fascial incision, morbidities such as pain, neurovascular injury, infection, blood loss, haematoma, seroma, and fracture can plague the technique. Limited quantities, especially in children, can also be an issue with autograft. Cancellous or cortico-cancellous structural grafts can be milled and used for posterolateral fusion, interbody fusion, and can be mixed with other graft substitutes/expanders. Morbidity profile aside, autograft still remains the gold standard for spinal arthrodesis with regards “ideal properties” of bone grafts.
Allograft – Currently, allograft is the most common substitute for autograft bone in spinal fusion. Allograft is primarily osteoconductive, with minimal osteoinductive potential. Avoidance of donor site morbidity, quantity issues, and surgical time saving are all features of allograft. Increased costs and potential for infection are negative issues. Preparation can vary and fresh unprocessed grafts are no longer used. Freeze drying (lyophilization) involves drying of the grafts before freezing at sub zero temperatures, and the technique reduces immunogenicity, though upon rehydration, structural strength is lost by around 50%. Low dose radiation (< 20kGy) can also be used to process the grafts, as can ethylene oxide, yet both techniques also reduce mechanical strength of the trabecular architecture. With adequate donor screening and tissue processing, the risk of developing HIV from an allograft is estimated to be less than 1 in a million.
Incorporation of allograft is similar to that of autograft, though the process takes more time. Allograft cancellous particles provide a larger surface area and therefore incorporate faster. Studies suggest that mulched allograft femoral heads provides as good a fusion rate in posterior spinal surgeries for children with scoliosis as does the use of autograft. Combination of osteoinductive agents (BMP etc) with allograft is now possible and will likely enhance its further use. Structural fibular allografts in cervical interbody fusion and femoral ring allografts in lumbar interbody fusion have been well described and have very high rates of fusion.
Arthrodesis of the spine is the preferred surgical treatment for a number of pathological disorders. This process is dependent on three primary components: osteogenic cells with osteoblastic potential, osteoinductive growth factors and an osteoconductive scaffold that facilitates bone formation and vascular ingrowth. Several systemic and local factors are known to affect the rate of spinal fusion. Autogenous bone graft remains the gold standard graft material for spinal fusion. It is the only graft material that supplies the three primary components necessary for a solid fusion. Unfortunately autogenous bone is only available in limited quantities and the procurement of autograft is associated with significant donor site morbidity. A number of different bone graft materials have been developed as alternatives to autograft. These materials may be classified into two major groups, bone graft extenders used to augment autograft, or bone graft substitutes. Several different bone graft materials have been developed including allograft, osteoconductive matrices, demineralised bone matrices, bone marrow aspiration, autologous platelet concentration, growth factors and gene therapy.
Allograft is currently the most widely used substitute for autogenous bone. Because any osteogenic cells are eradicated during the tissue processes, allograft is primary osteoinductive with minimal osteoinductive potential. Processing may affects the structural and biological characteristics of a graft. The incorporation of allograft occurs by a process similar to that observed with autograft but more slowly and is less complete.
Osteoconductive scaffolds do not contain any osteogenic cells or osteoinductive factors and are used as a composite graft as a carrier for either osteogenic cells or osteoinductive growth factors. They are biocompatible and do not illicit a response. There is also no inherent risk of infection and availability is unlimited. These materials are brittle with poor mechanical properties and need to be protected from excessive biomechanical forces until fully incorporated. A number of osteoconductive scaffolds have been developed including ceramics, calcium sulfate, mineralized collagen, bioactive glasses, and porous metals.
Dematerialized bone matrices (DMPs) are osteoinductive with variable osteoconductive properties. DMPs consist of Type I collagen and non-collagenous proteins including multiple signaling proteins. The osteoinductive activity of DMPs is due to a small fraction of bone morphogenic proteins. There is significant variability in the osteoinductive potentials and clinical efficacy of DBMs. DBMs are most effective when combined with autograft or bone marrow aspirate.
Bone marrow aspiration provides osteogenetic cells and osteoinductive growth factors but must be combined with an osteoconductive carrier to form a composite graft. It is associated with minimal morbidity compared to the use of autograft and is easily obtained. Unfractionated bone marrow contains only moderate osteogenic potential. Selective retention technology can increase the number of osteogenic cells then combined with an osteoconductive carrier such as a collagen sponge or DBM.
Activated platelets release multiple factors that may enhance bone formation by promoting chemotaxis, cellular proliferation and differentiation of stem cells. Platelets do not release BMPs so this autologous platelet concentrate is not inductive. Concentrated platelet rich plasma gel is combined with an osteoconductive scaffold or osteogenic cells to form a composite graft for implantation. The capacity for fusion by this technique may be inferior to autologous graft.
Bone morphogenetic proteins are low molecular weight proteins related to the transforming growth factor beta superfamily. They bind receptors on the surface of osteoprogenitor stem cells and activate intracellular signal transduction cascades resulting in the osteoblastic differentiation of pluripotential stem cells. Recombinant BMPs are typically combined with an osteoconductive carrier to form a composite graft. Recombinant BMPs have been used successfully in spinal fusions and may be superior to autograft.
Gene therapy involves the transfer of specific DNA sequence into target cells that express the protein of interest. Gene therapy may provide a more potent osteoinductive signal than recombinant growth factors because the sustained local release of osteogentic proteins may be more physiologic than the administration of a single large dose of recombinant factors. There are potential safety concerns and economic issues.
Autogenous bone remains the gold standard of graft material; however composite grafts consisting of multiple materials may prove to be efficacious for stimulating a spinal fusion.
Bone morphogenetic proteins are low molecular weight proteins which have extensive similarity in structure and function to the transforming growth factor beta factors. They bind receptors on the surface of osteoprogenitor stem cells and activate intracellular signal transduction cascades resulting in the osteoblastic differentiation of pluripotential stem cells.
Bone morphogenetic proteins (BMP) are being increasingly used in orthopaedic surgery including spinal fusion. These small molecules are capable of inducing bone formation when delivered in the appropriate concentration and on the appropriate scaffold. Recombinant BMP usually is combined with an osteoconductive carrier to form a composite graft. The osteoconductive carrier not only supports cellular adhesion but restricts the diffusion of these soluble factors away from the fusion site increasing local concentration of BMP. There is currently no consensus as to the ideal carrier but the optimal carrier may be dependent upon the specific clinical application for which it is used. In addition osteogenic cells that are able to respond to these osteoinductive signals must also be present for a successful spinal fusion to occur.
Not all BMPs are equally effective. Over 15 BMPs have been identified and there are currently only two Food and Drug Administration (FDA)-approved BMPs (BMP-2 with a full PMA approval and BMP-7 with an HDE approval).
Recombinant BMPs have been used successfully in anterior lumbar interbody fusions. Multiple animal studies have shown recombinant human BMP to be superior to autograft in the cervical, thoracic and lumbar spine, while human clinical trials have also shown recombinant human BMP-2 to be superior to autograft for anterior fusion. Similarly, multiple animal studies and clinical trials have shown that recombinant human BMPs result in equivalent or superior fusion rates for posterior spinal fusion compared to autograft. The use of BMPs may obviate the need for decortication and overcome the negative effects of nicotine and anti-inflammatories
In all studies, the concentration of BMPs necessary to produce successful spinal fusion was substantially greater than physiological levels, raising several potential safety concerns including bony overgrowth and bone formation which may lead to neural compression or unintended extension of the fusion. There are also the risks of local toxicity and a host immunologic response. These potential complications related to off-label use of BMPs need to be understood. For this reason, it is essential to determine the appropriate dose for each clinical application and develop efficient carrier systems.
There are economic concerns associated with the use of this new technology. A single treatment of recombinant human BMP is expensive but may be cost effective if clinical outcomes are improved or other costs are avoided. The increased cost of BMP may offset the complications associated with harvesting autograft bone. When used properly, these molecules have the potential to eliminate the need for iliac crest bone graft harvest and improve the speed and success of spinal fusion.
In this lecture, a summary of Ron Beetham’s life was presented, focused on the pivotal roles he played in the foundation of the Facet Club, (later to become the Spine Society of Australia), I.S.S.L.S. and on his contribution to orthopaedic education in Asia. Reflections based on 50 years in spinal surgery were presented, dealing with the highs and lows of this fast-evolving specialty. Unresolved aspects of disc pathology and spinal cord injury will be discussed.
* The Ron Beetham Memorial Lecture is an eponymous lecture for inclusion in the Annual Scientific Meeting of the Spine Society of Australia. (William) Ron Beetham (1925–2003) was a co-founder of the Facet Club in 1970. The Facet Club was the predecessor to the Spine Society of Australia which came into being in 1990. Ron Beetham was a notable spinal orthopaedic surgeon and humanitarian who practiced in Ballarat and was a major contributor to spinal surgery in Australia and overseas.
This lecture is to honour a founder of what has become the Spine Society of Australia and the eponymous lecture should make some historical reference to this effect. The Ron Beetham Memorial Lecturer will be selected by the Executive at its final meeting of the calendar year and invited by the President to give a half hour dissertation on a topic of mutual agreement between the President and the invited lecturer. The topic may be wide ranging and not necessarily confined to the science and practice of spinal surgery. The lecture will be delivered at the Annual Scientific Meeting following selection of the lecturer and subject to agreement. The occasion is marked by a presentation of an award.
Injuries of the cervical spine can be classified into six categories according to a mechanistic system describing the biomechanical deficiencies incurred in a cervical spine injury. However high velocity flexion compression loads cause multiple contiguous and noncontiguous fractures due to multiple force vectors. A universal classification system cannot be applied.
Instability exists if there is greater than 3.5 mm of translation or greater than 11 degrees of angulation as compared to other segments. The degree of ligamentous injury on MRI correlates with instability in patients with lateral mass facet fractures, with rupture of multiple ligaments including the anterior longitudinal, posterior longitudinal, interspinous, or facet capsule. Patients with less than 13 mm of narrowing of the sagittal canal are predisposed to neurologic injury. Vertical compression injuries cause canal occlusion and vertebral column shortening. The timing of surgery in cases of spinal cord injury is controversial. There is no difference in outcome between early (< 72 hours) and late (> 5 days) surgery. However, there remains at least a theoretical benefit to early surgery.
Compression-flexion injuries result in loss of the anterior column by compression followed by the posterior column in distraction. The injury is considered unstable if there is a vertical cleavage fracture of the vertebral body or displacement. Treatment includes a cervical orthosis or halo for minor injuries, depending on the degree of kyphosis. Major injuries with displacement should be treated surgically by anterior corpectomy and plate or an anterior/posterior fusion, depending on the degree of posterior instability.
The most common level of vertical-compression injuries is at the C6 or C7 level. Minimally displaced injuries can be treated with a collar or halo. Fragmentation and peripheral displacement of the bony fragments needs a halo followed by surgery and this may include an anterior corpectomy and plating.
Distraction-flexion injuries may result in facet sub-luxation with less than 25% displacement, or dislocation of one (UFD) or both (BFD) facet joints. When there is 3 mm of translation (25%), the canal is occluded 20–25%. With 6mm of translation (50%), there is 40–50% canal occlusion. MRI can help analyse the soft tissue and ligamentous injuries. In UFD, all posterior ligamentous structures including joint capsule, and half the disc annulus are disrupted. Disruption of ALL and PLL is not necessary to create a UFD. In addition to the posterior structures, the ALL, the PLL and disc are disrupted in BFD. Rupture of the intervertebral disc may include posterior herniation or circumferential disruption. All distraction flexion injuries should be reduced closed. The necessity of a preoperative MRI is undetermined. Preoperative MRI is recommended if there is an unreliable exam due to the patient being uncooperative, if there is neurological worsening with, or failure of closed reduction. If the patient is neurologically intact and closed reduction successful, a posterior cervical fusion is advocated if there is no evidence of an extruded disc on the post reduction MRI. If the closed reduction failed, or MRI indicated, and there is no evidence of a herniated disc, an open posterior reduction followed by fusion is performed. Anterior discectomy with reduction, a graft and a plate is performed for a herniated disc.
Compression-extension injuries fail by compression of the posterior elements followed by distraction of the anterior elements. There are unilateral or bilateral fractures of the laminae/neural arch with degrees of displacement. Undisplaced neural arch fractures can be treated with a cervical orthosis or halo. Displaced neural arch fractures are treated with a posterior cervical fusion.
There are two stages in the distraction-extension injury group. The anterior longitudinal ligament is disrupted with possibly a transverse fracture of the body. With more major injuries, there is a significant displacement injuring the posterior column. Stage 1 injuries can be treated with a halo and Stage 2 with an anterior decompression and fusion with a plating device. There are two stages to lateral flexion injuries. Minor injuries include asymmetric centrum fracture and a unilateral arch fracture. In addition, there is displacement of the body with contralateral ligamentous failure in major injuries. The treatment for Stage 1 is usually a collar while treatment for Stage 2 is usually a posterior cervical fusion.
Posterior stabilization procedures may be performed with wires and cables with or without rods. Posterior clamps usually are not recommended; while plates and screws are preferred. The plates and screws are biomechanically superior to wiring and avoid canal penetration. They are ideal when there is loss of the posterior elements. Pedicle fixation should be considered when operating on the C2 or C7 level.
One in five patients may have complete disruption of vertebral artery blood flow. This occurs most commonly with flexion-distraction or flexion-compression injuries. Vertebral artery evaluation is recommended in patients with flexion injuries and symptoms consistent with vertebral artery insufficiency.
It is important to understand the mechanism of injury; to understand which elements are compromised. We have to get the appropriate imaging studies, we have to be cognizant of the fact that the vertebral artery may be injured, or there may be an associated herniated disc. We have to understand the degree of instability, which dictates the appropriate treatment and we have to understand the risk benefit of the specific internal fixation systems that we use.
At the latest follow-up, there was no measurable subsidence of the devices except in one case at L5S1 due to a technical error and no evidence of device migration. The measured range of motion in flexion-extension ranged from 3 to 16 degrees (mean range of motion, 6 +/− 4 degrees). L4–L5 level is more mobile: average 8.4 degrees. With regards to sagittal balance, there was no significant change in any of the variables studied including sacral tilt, pelvic tilt, or overall lordosis after placement of total disc arthroplasty. Only the lordosis at the level above the prosthesis was significantly decreased. The position of the implant on AP and lateral x ray was analyzed and correlated with the clinical results. Less than 19% of offset on AP view had no influence on clinical results. One complication, a ureter injury occurred during the approach in one procedure. One left iliac vein injury occurred per-operatively and treated with vascular clip. One patient with two discs with persistent low back was re-operated for posterior fusion with a significant improvement of pain at two years. This patient had been operated 3 times before for disc herniation and recurrence of HD.
As a rule, after 10 to14 days a revision approach via the same incision should be avoided. At L5–S1 it is best to use the opposite side retroperitoneal approach. L4–5 should be approached either transperitoneally or via a more lateral retroperitoneal incision. Returns to L3–4 and L2–3 are best via a more lateral approach as well. Right-sided approaches should only be used for L5–S1. For higher levels, potential injuries to the inferior vena cava make the risk prohibitive.
Clinical outcomes variables, assessed preoperatively and at 3, 6, 12 and 24 months, included the Japanese Orthopaedic Association score (JOA) for low back pain, SF-36, lumbar and leg pain visual analog scale (VAS), and Odom score. At these assessments flexion/extension radiographs were performed and yearly MRIs have been obtained.
Pre-operatively, the mean VAS was 70.3/100. At three months, VAS was significantly reduced (P< 0.01) to a mean 18.3 with further reductions to 17.0 at 6 months and 14.6 at 24 months. At 3 months post-operation, all categories of the SF-36 scores (except general health) had shown significant improvement compared with preoperative values. At 1 year, and sustained at 2 years, the SF-36 scores were comparable with an aged and sex matched normal population form France. The JOA score (15 point scale) significantly improved (P< 0.01) from 6.0 preoperatively to 12.9 at 24 months after reaching a plateau at 3 months (12.5).
From Odom’s assessment at 3 months 85% of subjects were categorized as ‘good’ or ‘excellent’, this being sustained over the period of the study, with results at 6 months and 24 months 90% and 88%, respectively.
Of the total cohort of 262 cases, only four implant-related failures have been observed to date.
The few implant related failures all occurred in the first year, after which some minor implant modifications were made. There have been no subsequent implant related failures.
The cardiovascular effects of pulmonary cement embolism were investigated using an animal model.
Pulmonary hypertension was more severe in the CaP cement group. This may have been due to the disintegration of the CaP cement resulting in blockage of more pulmonary vessels compared to the PMMA cements.
Using the positional scanner four postures were investigated: Neutral Standing, Neutral Sitting, Flexed Sitting and Extended Sitting. These scans comprised simultaneous sagittal and coronal non-contiguous slices to facilitate three-dimensional registration and reduce acquisition time. Conventional MRI was then used to scan the subject at higher resolution contiguous slices. After segmentation and surface extraction of all bones from all scans, each bone geometry was registered with each of the positional scans to produce high quality in vivo skeletal position data.
For 2 subjects, each of the 5 lumbar vertebrae and the pelvis were registered 5 times in the 4 postures to investigate intra-tester reliability. This resulted in 48 sets of 5 registrations. Each bone surface was represented by surface points and a local coordinate system. Angular and translational differences between coordinate axes were examined for each set of five registrations.
The most appropriate classification of traumatic thoracolumbar (TL) spine injuries remains controversial and current systems can be cumbersome and difficult to apply. No classification aids decision making in clinical management. Clinical spine trauma specialists from institutions around the world were canvassed with respect to information deemed pivotal in the communication of TL spine trauma and the clinical decision making process. Traditional injury patterns were reviewed and reconsidered in light of these essential characteristics. The reliability and validity of an earlier version of this system has been demonstrated.
The Thoracolumbar Injury Classification and Severity Score (TLICS) was devised based upon the three most important injury characteristics: 1) morphology of injury determined by radiographic appearance, 2) integrity of the posterior ligamentous complex, and 3) neurological status of the patient. These characteristics are largely independent of each other. A composite injury severity score can be calculated from these characteristics stratifying patients into surgical and non-surgical treatment groups. The three principal injury patterns are compression (including burst – 1 point each), translation/rotation (3 points) and distraction (4 points). Neurological status can be classified as a nerve root injury (1 point), a complete (ASIA A-2 points) or incomplete injury (3 points) to the spinal cord or conus, or injury of the cauda equina (3 points). Disruption of the posterior ligamentous complex and facet joint capsules results in instability. Disrupted posterior ligaments can be seen as subluxation or dislocation of a facet, interspinous widening, or MRI evidence of ligament discontinuity. Failure of the posterior ligamentous complex can be classified as indeterminate (2 points) or definitely disrupted (3points).
Coexisting clinical factors (qualifiers) may alter decision making by virtue of their effect on stability, general management or effect on healing. Metabolic disorders such as ankylosing spondylitis, DISH, osteoporosis and age may influence treatment. Injury characteristics such as excessive kyphosis, severe vertebral body collapse and sternal fracture may influence outcome and modify treatment. Treatment options might be influenced in patients with head injuries or polytrauma. The impact of these clinical qualifiers on patient care must be evaluated.
Once all the major variables have been assigned points, a total TLICS Score can be determined. Patients with 3 or less points are non-operative candidates while patients scoring 5 or more points should be considered for surgery. Clinical qualifiers may modify treatment. The morphology of the injury, neurological status, and integrity of the posterior ligamentous complex can help guide the management of TL injuries. Incomplete neurological injuries warrant anterior decompression if posterior realignment is ineffective in relieving neurological compromise. Distraction and translational injuries, and disruptions of the posterior ligamentous complex are managed optimally with an initial posterior approach for realignment and stabilization. Although there will always be limitations to any cataloging system, the TLICSS reflects accepted features cited in the literature important in predicting spinal stability, future deformity, and progressive neurological compromise. This classification system is intended to be easy to apply and to facilitate clinical decision making.
Introduction Reported clinical results suggest that vertebroplasty is a safe and effective technique for providing pain relief. However, information about the long-term effect of PMMA on the adjacent intervertebral discs and the augmented bone is lacking. Adjacent intervertebral discs may be at higher risk of degeneration due to nutritional constraints. Bone loss in augmented vertebrae may occur due to mechanical stress-shielding or toxicological effects.
The aim of the present study was therefore to investigate the effect of PMMA augmentation on intervertebral disc and bone tissue after 6 and 12 months, using an animal model.
Postmortem, T1- and T2-weighted sagittal and axial MR images were taken prior to fixation in 80% ethanol. Spines were cut into specimens containing one intervertebral disc and half of the two adjacent vertebrae. The discs which were two levels above the first augmented vertebra served as controls. Microsections were stained with H&
E, Goldner, Alcian blue-PAS and Safranin O. MRI signal intensity and morphology of discs were evaluated qualitatively. Histomorphological analysis of discs and endplates was conducted using published criteria [
The risk of degenerative changes of intervertebral discs should be considered in patients undergoing vertebroplasty.
