To determine presenting features, treatment modalities and associated outcome following treatment of spinal dural arteriovenous fistulas in a tertiary centre.

Retrospective cohort study of patients with SDAVF assessed at a single tertiary referral centre, between 1999 and 2009. Medical records were used to identify intervention type, pre- and post-intervention Aminoff-Logue disability score (ALDS), recurrence rate, follow-up time and discharge status. Statistical analysis was performed using Wilcoxon signed rank.

26 patients were identified with 23 receiving intervention. Two were unavailable for follow up. Endovascular embolization was performed successfully in 13 patients, recurrence occurred in 6 of these, 3 of which were subsequently treated surgically. Surgery was the initial treatment for 10 patients due to either unsuccessful embolization attempt or proximity of the fistula to spinal artery feeders; only 1 of these recurred. ALDS-gait reduced (improved) by a mean of 0.33 points following intervention but this was not statistically significant (P=0.0645). There was negligible change in micturition and bowel ALDS. Improvement in ALDS was greater in patients treated with surgery first and also in patients whose fistula did not recur. Mean follow-up was 38 months with 56% of working age patients returning to work.

Both embolisation and surgery achieved the primary aim of reducing disease progression, leading to an improved ALDS. Outcome was superior if initially treated surgically and recurrence occurred more frequently in patients treated endovascularly. The small number of patients in our cohort emphasise the need for further studies into this group of patients.

It has been shown that a cognitive function (CF) loss can occur after hip or knee arthroplasty procedures, with an incidence of 40 to 70%. The pathogenesis remains unclear but studies suggest some form of brain emboli; although both trans-cranial doppler and trans-oesophageal doppler have both shown emboli per-operatively a correlation has never been shown with CF loss post-operatively. In contrast, in the cardiothoracic literature an embolic cause is widely accepted for detectable post-operative CF drop. The purpose of this study was to ascertain whether MRI could show evidence of embolic phenomena in patients undergoing hip or knee arthroplasty.

Twenty-five patients presenting for hip or knee arthroplasty procedures were consented for this study. Brain MRI scans and MR angiograms were performed 1 week pre-operatively and within 1 week post-operatively using a Phillips 1.5Tesla MRI unit. All scans recorded were independently reviewed by 2 radiologists. A series of tests to examine several modes of cognitive function were carried out by a clinical psychologist pre-operatively, and at 1 week post-operatively. The CF tests showed a clinically significant drop following surgery in 64% of cases – this is in keeping with other recently published data.

None of the post-operative scans or angiograms showed overt evidence of new lesions. Three Scans had equivocal tiny brainstem hypodensities on a single slice with no correlating abnormality on diffusion images to support the presence of new ischaemia.

We conclude that either the aetiology of post-operative CF drop following arthroplasty is not embolic in nature, or that with current technology MRI brain scans even with angiograms are not sensitive enough to show the corresponding abnormality. With currently available equipment there appears to be no benefit from using MRI as a tool to evaluate post-operative CF loss in this group of patients.

Hyaluronic acid (Hyalunan, HA), β-1,4-linked D-glucuronic acid and β-1,3 N-acetyl-D-glucosamine polysaccharide, is a nonsulfated glycosaminoglycan(GAG) conserved in the extracellular matrix (ECM). Due to its biocompatibility, biodegradable properties, HA is widely applied for tissue engineering. However, HA also has defects for tissue engineering such as mechanical properties, difficulty of handling. Thus, it is various modified by chemical reaction to produce HA derivative. HA plays an important role in tissue morphogenesis, proliferation and cell differentiation. Ascorbic acid (AA) has an effect on collagen synthesis and bone mineralization. Ascorbate levels also have a significant effect on osteoblast proliferation and alkaline phosphatase (ALP) expression. However AA is weak to heat and light, thus it is easily degradable. Consequently, we conjugated HA with AA in order to make it more stable and effective. In this study, we prepared HA-AA conjugate and evaluated activity of products in pre-osteoblast.

To produce more effective conjugation, we synthesised HA derivative, HA-N-hydroxysuccinimide, an activated ester of the glucuronic acid moiety. This HA-active ester intermediate is a precursor for drug-polymer conjugates. The degree of substitution was calculated by NMR analysis. The modified HA was dialysed and lyophilised. The yield of conjugation is calculated by Gel Permeation Chromatography (GPC). After the process, HA was conjugated with AA once again as previously mentioned. In this study, the resultant HA-AA conjugate was tested on MC3T3-E1, murine pre-osteoblast cells. We examined cellular viability (cytotoxicity), proliferation and gene expression. The expression of Type 1 collagen was examined by RT-PCR and western blot. Osteocalcin (OCN), osteopontin (OPN) and bone sialoprotein (BSP), bone proliferation and differentiation marker were detected by RT-PCR. Alkaline phosphatase assay was also performed. For confirmation on bone mineralization, alizarin red staining and von Kossa staining was performed.

In conclusion, the in vitro data demonstrate that HA-AA conjugate has an important role in bone formation, as it can increase proliferation and osteogenic differentiation of MC3T3-E1 cells. These observations further support the use of in vivo system for tissue engineering applications.

Constrained condylar knee (CCK) prosthesis offers an implant option for complex revision total knee arthroplasties in which stable varus-valgus constraint as well as rotational control is needed for severe bone defect and ligament insufficiency. The aim of this study was to evaluate the clinical and radiological outcome of CCK prosthesis in revision TKA.

Fify-one revision TKAs performed using CCK prosthesis between Jan. 1998 and Feb. 2006 were performed. The mean follow-up period was 5 years and 3 months (2 to 9 years) and the interval between initial and revision TKA was 8 years (4 months to 21 years). The mean age was 67 years. Range of motion (ROM), knee society (KS) score, hospital for special surgery (HSS) score, complication rate and failure rate was evaluated. The tibiofemoral angle and radiolucent line was also evaluated on plain radiograph.

The mean ROM improved from 81.9° to 102°. The mean KS score improved from 49.3° to 79.7°, and KS function score from 50.3 to 71.0 (P< .001). The mean HSS score improved from 50.7 to 78.7 (P< .001). Tibiofemoral angle improved from valgus 3.1° to valgus 5.6° (P< .001). Radiolucent line more than 2mm was observed around 4 femoral and 4 tibial components. Complications including 1 skin necrosis, 1 tibial tubercle nonunion, 2 infections, 3 periprosthetic fractures and 5 arthrofibrosis were observed. Overall rating was excellent or good in 88% at the last follow up.

Revision TKA using CCK prosthesis showed comparable results with other reports in average 5 years follow-up.

The aim of this study was to evaluate the rotational axis of the tibia and the association of its axis to tibial coronal alignment after TKR.

TKRs were performed using navigated mobile bearing system (40 knees), conventional mobile bearing (48 knees) and conventional fixed bearing (40 knees) and preoperative and postoperative CT scans were assessed using 3D image reconstruction-analysis program. The tibial AP axis which was defined as the line connecting the middle of the PCL and the medial edge of the patellar tendon attachment was measured relative to the AP axis of distal femur preoperatively and postoperatively, as well as the coronal angle of the tibia and posterior slope. The tibial coronal alignments in navigation, postoperative plain radiograph and CT were compared.

The AP axis of the tibia was in 2.10° internally rotated position relative to the AP axis of the femur preoperatively and 3.54° postoperatively (range, 19.5° internal rotation to 16.8° external rotation). The coronal angle of the tibia was 0.46° varus on plain radiograph, 0.72° varus on CT, 0.37° valgus in navigation (p=0.005). Posterior slope was 2.53° on plain radiograph and 0.67° in navigation (p< 0.001). There was no correlation between postoperative rotational position of the tibia relative to the femur and the difference in the tibial coronal angle between navigation data and CT.

The proposed anteroposterior axis of the tibia centered between 0 to 5 degrees internally rotated position relative to the femur but showed wide range of deviation. The rotation angle of the tibial cutting in navigated TKR did not influence on the postoperative measurement discrepancy between navigation and CT.

The aim of this study was to evaluate passive kinematics of a mobile-bearing, ultracongruent (UC) total knee design compared with a mobile-bearing, posterior stabilised (PS) design intraoperatively using navigation system.

Thirty-four knees of 24 patients which had undergone total knee arthroplasty with UC prosthesis (E-motion^®, Aesculap, Tuttlingen, Germany) for primary osteoarthritis and fifteen knees of 14 patients with PS prosthesis (E-motion^®) were included in this study. Thirty-one female and seven male patients were included and the mean age was 70.4 years. Patients were followed up for 7.26 months (6 to 12 months). Intraoperative kinematics including valgus/varus rotation, internal/external rotation, and anterior/posterior translation was assessed from 10° to 120° of passive flexion before and after total knee replacement using a surgical navigation system (Orthopilot^®, Aesculap). The range of motion (ROM) was measured preoperatively and at the final follow up.

The tibiofemoral alignment in 10° flexion changed from varus 5.85° to valgus 0.38° in UC group and changed from varus 7.45° to valgus 1.08° in PS group (p> 0.05), the magnitude of varus rotation during flexion was 0.01° in UC group and 4.08° in PS group (p< 0.05). PS knee showed the tendency to slight varus alignment during flexion but UC knee showed the tendency toward valgus alignment fter midflexion. The mean internal rotation during flexion was 10.3° in UC group and 13.2° in PS group (p> 0.05). The translation of the femur was 4.99mm posteriorly in UC group and 3.24mm posteriorly in PS group at 120° flexion (p> 0.05). The maximum flexion angle at the final follow up was 123° in UC group and 118° in PS group (p> 0.05). Total knee arthroplasty with high flexion PS prosthesis showed good ROM and satisfactory early clinical results.

UC total knee design showed less varus rotation during flexion, more valgus pattern in higher flexion angle than PS design, similar internal rotation angle and pattern, and similar posterior translation at 120° flexion with PS design.

Clinical experience has shown the needs for high flexion. The aim of this study was to evaluate the clinical and radiological results of a fixed bearing high flexion posterior stabilized (PS) total knee arthroplasty (TKA).

Between July 2001 and December 2005, 422 TKAs in 288 patients were performed with high flexion PS prosthesis and 378 knees of 258 patients had been followed up for 2 to 6.5 years (mean: 3 years 11 months). We evaluated range of motion (ROM), Knee rating system of the Hospital for Special Surgery (HSS) and Knee Society (KS) score, and radiological results.

The mean flexion improved from 110.1 degrees to 126.7 degrees at the latest follow-up. 333 knees (88 %) showed more than 120 degrees of flexion, 105 knees (28 %) more than 140 degrees of flexion. The mean KS clinical score improved from 39 to 93 points (p< 0.01) and KS function score, from 40 to 85.4 points (p< 0.01). The mean HSS score improved from 41.2 to 86.3 points (p< 0.01). In 28 knees, radiolucent line of 1–2 mm in width was observed at zone 1 without symptoms. Aseptic loosening in 4 knees, Mid-flexion instability in 2 knees, superficial infection in 3 knees and deep infection in 3 knees were observed.

Total knee arthroplasty with high flexion PS prosthesis showed good ROM and satisfactory early clinical results. Complication rate was similar to those of other series. Close observation and serial radiological evaluation are needed for long term results.

Background : A composite femoral stem was introduced with a structural stiffness similar to that of the native femur to promote proximal load transfer. This consisted of a cobalt-chromium alloy core surrounded by an injection-moulded layer of polyaryletherketone covered with a porous titanium mesh.

Material and Methods: 31 consecutive primary total hip replacement stems were implanted in 26 patients with an average age of 37 years (range 17–57) using the Epoch stem (Zimmer, Warsaw, IN) as part of a prospective multi-centre trial. A cementless Harris-Galante I acetabular component with a 28mm polyethylene insert (Zimmer) was used in 29 cases, a Plasmacup with 28mm polyethylene insert (Aesculap, Tuttlingen, Germany) in 1 case and a bipolar head in 1 case. Annual follow-up with Harris Hip Scores and radiographic evaluation was performed for a mean of 10.1 years.

Results : Harris Hip Scores improved from a mean of 52 points preoperatively to 90 at the time of last follow-up. Radiographs showed no stem migration or loosening. 4 cases with polyethylene wear showed trochanteric osteolysis. Specific radiographic features noted were a sclerotic halo in Gruen zones 1 in 8 cases, calcar rounding in 10 cases and improvement in calcar appearance with squaring of the calcar in 4 cases. Calcar resorption was seen in 1 case associated with polyethylene wear. There have been 8 instances of revision of the head or acetabular component- 3 liner exchanges for polyethylene wear, 3 acetabular component revisions for liner dissociation with associated cup damage, 1 acetabular component revision for infection and 1 bipolar head revised to unipolar head with cementless acetabular component for pain. No stem has required or requires revision.

Conclusion : The Epoch stem resulted in an excellent clinical outcome with evidence of radiographic stability and proximal bone preservation, and no cases of stem revision in a cohort of young patients with long-term follow-up.

Introduction: A composite femoral stem was introduced with a structural stiffness similar to that of the native femur to promote proximal load transfer. This consisted of a cobalt-chromium alloy core surrounded by an injection-moulded layer of polyaryletherketone covered with a porous titanium mesh.

Materials and Method : 31 primary total hip replacement stems were implanted in 26 patients with an average age of 37 years (range 17–57) using the Epoch Stem (Zimmer, Warsaw, IN) as part of a prospective multicentre trial. A cementless Harris-Galante I acetabular component with a 28mm polyethylene insert was used in 28 cases, a Plasma cup (Aesculap) in 1 case and a bipolar head in 2 cases. Annual follow-up using Harris Hip Scores and radiographic evaluation was performed for a mean of 10.1 years.

Results: Harris Hip Scores improved from a mean of 56 points preoperatively to 90 at the time of last follow-up. Radiographs showed no stem migration or loosening. 4 cases with polyethylene wear showed trochanteric osteolysis. Specific radiographic features noted were calcar rounding in 10 cases and improvement in calcar appearance with squaring in 4 cases. Calcar resorption was seen in 1 case associated with polyethylene wear. There have been 9 instances of revision of the head or acetabular component – 3 liner exchanges for polyethylene wear, 3 liner exchanges for dissociation, 1 acetabular component revision for infection and 2 bipolar heads revised to unipolar heads with cementless acetabular component for pain. No stem has required or requires revision.

Discussion: The Epoch stem resulted in an excellent clinical outcome, with evidence of radiographic stability and proximal bone preservation, and no cases of stem revision in a small cohort of young patients at 10-year follow-up. The limitation of reconstruction in this cohort of young patients has been the acetabular component.

Purpose: To establish and validate animal model for Achilles tendon disease with subsequent examination of histology, biochemistry and biomechanics

Methods: Experimental rats were subjected to an over-exercise running regime. Achilles tendons were analyzed for histology, glycosaminoglycan content, collagen content, collagen subtype, collagen cross-linking (hydrothermal isometric tension testing), and mechanical properties.

Results: Experimental rat Achilles tendons demonstrated: decreased semi-quantitative grade for collagen organization (2.9 vs. 3.7, p < 0.05), decreased semi-quantitative grade for collagen staining (1.9 vs 3.5, p < 0.05) and increased nuclear numbers per high-power field (527 vs. 392, p < 0.05). Immunohistochemical analysis revealed a predominance of by fibroblasts or endothelial cells. The total collagen content remained unchanged (84.3 vs. 89.0% p=0.38), while the glycosaminoglycan content was increased (17.5 vs. 9.0% p=0.02). Differences in collagen cross-linking were characterized by a greater proportion of reducible intrahelical crosslinks. These differences did not translate into a decrease in ultimate tensile failure during mechanical testing (UTS of 77.8 vs. 88.8 N, p=0.26).

Conclusions: Over-exercise model produced Achilles tendons with histology and biochemistry consistent with the animal and human tendon disease and characteristic of a remodeling response not an inflammatory response.

Introduction Historically, lumbar discography has been one of the most controversial subjects in the management of discogenic low back pain. The diagnostic value of normal psychometric specific pain provocation by disc pressurization has emerged. The sensitivity, specificity and accuracy of discography as a diagnostic test are not in doubt. In clinical discography pain reproduction and location are essential elements. There is an accepted rate of 0–10% false positives. This rate is influenced by occupational disability and abnormal psychometric profiles. By contrast, little attention has been given to false negative results and their outcomes if surgically treated. Traditionally, whether or not the test is considered to be positive or negative is determined immediately after completion of the diagnostic procedure. This study shows that patient’s pain reproduction may occur up to 24 hours after the discogram which often initially interpreted as a true negative when it is actually a false negative result. This study verifies the existence and significance of a false negative through the patients’ treatment and outcomes.

Methods In this study, 150 patients underwent discography for investigation of chronic persistent low back pain (CPLBP). All patients had a control (morphologically normal) discogram at the level above the degenerative segment. No patients with abnormal psychometric profiles or compensation were included. All patients were followed up 24 hours post discogram by the radiologist to further assess their clinical status. Ten of the patients (7.5%) were considered to have a false negative discogram, as per the Dallas Discogram Scale. The surgeon correlated the delayed response on the subsequent follow-up. These ten patients were diagnosed as having a positive response and were treated surgically for their discogenic pain. VAS-B, VAS-L, ODI, RMD were collected prospectively. Preoperative and 6 month results were reviewed.

Results Seven of the 10 patients (70%) reported severe increase CPLBP and reproduction of pain within 8 hours of the discogram, while 3 patients (30%) did so in the ensuing 24 hours after the discogram. Surgical treatment was either by total disc replacement or anterior lumbar interbody fusion. All patients reported greater than 50% reduction in VAS-B and VAS-L and with improvements of greater than 50% in their ODI and RMD scores.

Discussion The clinical reliability of discography hinges on the subjective assessment of pain concordance as the discriminating factor in determining false positives from false negatives. Given the limitations of discography, all information about the patient should be considered prior to diagnosis, including clinical, radiological, historical, and psychometric factors. The delayed positive discography response is an important consideration for the patient, the radiologist, and the treating surgeon to be aware of. The results of this study verify the existence of this subgroup and justify their surgical treatment.

Introduction The CPS-Plus stem (Endoplus UK) is a polished double-taper with rectangular cross section maintained throughout for rotational stability. There are 5 stem sizes with proportionate offset, and 5 neck length options. A unique proximal stem centraliser has been shown to increase proximal cement pressurisation during insertion in-vitro, also assists with alignment of the stem and helps create an even cement mantle. RSA analysis has demonstrated linear subsidence in a vertical plane, without posterior head migration and valgus tilt.

We report a multi-centre prospective clinical trial. 231 hips in 223 patients have been entered into the study. 151 of these have reached 3 years follow-up.

Method Patients were recruited by surgeons working at three centres in the UK, and two in Norway. Merle d Aubigne and Postel, Harris, and Oxford hip scores were recorded pre-operatively and at follow-up (3, 6, 12, 24, 36, 60 months). Radiographic assessment included evaluation of subsidence and the presence of any radiolucencies.

Results Hip scores have been very satisfactory. Radiological subsidence is less than 1.5mm in over 95% of cases and only one stem has subsided more than 3mm. There has been one revision for deep sepsis, 7 dislocations and one femoral fracture, but none of these complications were related to the choice of femoral component. There have been no revisions for aseptic loosening. Kaplan Meier survivorship analysis at 36 months for aseptic stem loosening is 0.997 (95% CI 0.977 – 1) and for all-cause revision is 0.981 (95% CI 0.958 – 1). 53 hips had reached 5-year follow-up at 30/9/04.

Discussion The tradition of polished tapered stems arose from serendipity and most results have been excellent. The CPS-Plus stem represents an attempt to re-examine the issues relating to rotational stability, subsidence, cement pressurisation and offset. Earlier laboratory studies have now been supplemented by this clinical evaluation, performed in a number of different centres by several surgeons, and the evidence is encouraging.

In particular, the RSA subsidence characteristics, cement pressurisation and rotational stability already associated with this implant in-vitro have been supported by excellent survivorship analysis, and the authors believe that increasing familiarity with the concepts raised by this implant will result in clinical benefits in relation to polished taper cemented stem longevity.

Dissociation of the polyethylene liner of modular acetabular components is a rare occurrence, and previous reports have commented on the difficulty in diagnosis from plain radiographs. The radiograph is often incorrectly reported by radiologists as showing advanced polyethylene wear, causing delay in referral and increasing the complexity of treatment required.

We report 9 cases of late polyethylene liner dissociation of the cementless Harris-Galante II porous-coated acetabular component (Zimmer Inc, Warsaw, IN) which occurred without trauma or injury. This is the largest reported series to date.

In all cases, there was a common pattern of clinical symptoms and signs which is described.

Radiographs showed a distinct appearance with a radiolucency medial to the femoral neck in association with an eccentrically placed femoral head lying in contact with the acetabular metal shell. We have termed this the ‘crescent sign’.

We believe that the diagnosis can be made from a single antero-posterior pelvic radiograph without the need for previous films for comparison, or the need for arthrography. Clinicians should look specifically for the crescent sign when an eccentrically placed femoral head has been noted, in order to differentiate the more unusual diagnosis of dissociation from that of polyethylene wear. Early diagnosis and prompt referral prevents further damage to the femoral head and metal acetabular shell, thus reducing the complexity of revision surgery.

Introduction Primary and revision total hip surgery in the face of poor neuromuscular function, cognitive impairment or recurrent dislocation are fraught with complications. A useful option for such cases is the constrained acetabular component, or “captive cup”. We present the largest series reported to date, and use radiostereometric analysis (RSA) to assess cup migration.

Method Between February 1999 and September 2003 133 patients (141 hips) were identified as high risk of dislocation and were treated with a constrained acetabular component. One hundred and twenty cases were revision arthroplasties and 21 were primary replacements. Patients were assessed pre-operatively (WOMAC, Harris Hip Scores and SF-36). Defects were reconstructed with allograft (massive, morsellised or strut) where required. Most components were inserted into uncemented metal cups. Radiostereometric beads were inserted. Post-operatively patients were followed up regularly and clinical scores repeated. Radiostereometric analysis (RSA) was performed at 6 months, and then annually to assess prosthesis migration.

Results Mean follow-up was 3.1 years (range 1 – 5.6 years). At last review 26 patients had died, and 7 were lost to follow-up. There were 8 revisions for cup loosening. There were 5 dislocations and 2 dissociations in 6 patients. There was a statistically significant improvement in WOMAC and Harris Hip scores. RSA confirmed cup migration was greater than for non-captive cups, but was nevertheless minimal. Interestingly there was no statistically significant difference at 6, 12 and 24 months suggesting most migration occurs early on.

Conclusion Our results suggest the “captive cup” is an effective and safe option for the treatment of primary and revision arthroplasty in those at high risk of dislocation.

Introduction: Primary and revision total hip surgery in the face of poor neuromuscular function, cognitive impairment or recurrent dislocation are fraught with complications. A useful option for such cases is the constrained acetabular component, or “captive cup”. We present the largest series reported to date, and use radiostereometric analysis (RSA) to assess cup migration.

Method: Between February 1999 and September 2003 126 patients were identified as high risk of dislocation and were treated with a constrained acetabular component. One hundred and sixteen cases were revision arthroplasties and 10 were primary replacements. Patients were assessed pre-operatively (WOMAC, Harris Hip Scores and SF-36). Defects were reconstructed with allograft (massive, morsellised or strut) where required. All components were inserted into uncemented metal cups. Radiostereometric beads were inserted. Post-operatively patients were followed up regularly and clinical scores repeated. Radiostereometric analysis (RSA) was performed at 6 months, and then annually to assess prosthesis migration.

Results: Mean follow-up was 3.1 years (range 1 – 5.6 years). At last review 8 patients had died, and 2 were lost to follow-up. There were 7 revisions: 3 for infection, 2 for periprosthetic fractures, and 2 for aseptic loosening. There was one case of cup disassociation successfully treated with open reduction. There have been no further dislocations. There was a statistically significant improvement in WOMAC and Harris Hip scores. RSA confirmed cup migration was greater than for non-captive cups, but was nevertheless acceptable: 0.16mm medially, 0.47mm proximally, 0.16mm posteriorly. Interestingly there was no statistically significant difference at 6, 12 and 24 months suggesting most migration occurs early on.

Conclusion: Our results suggest the “captive cup” is an effective and safe option for the treatment of primary and revision arthroplasty in those at high risk of dislocation. RSA analysis confirms minimal prosthesis migration.

Introduction and Aims: Accumulating evidence suggests that bacterially derived endotoxins may contribute to aseptic loosening. This study determined whether lipopolysaccharide (LPS), the classical endotoxin from Gram-negative bacteria, can be detected in periprosthetic tissue from patients with aseptic loosening. We utilised an assay that detects all forms of LPS and is unaffected by beta-glucan-like molecules.

Method: Periprosthetic tissue from revision total hip arthroplasty and synovia from primary total joint arthroplasty were homogenised in PBS in endotoxin-free conditions. Non-specific amidases in the homogenates were inactivated at 100 degrees C. LPS was measured using the Endospecy assay (Associate of Cap Cod). Multiple dilutions of the homogenates were assayed to maximise sensitivity, while avoiding assay inhibition assessed by spike recovery determinations. Results were corrected for colour and spike recovery. Assay results were considered positive if the absorbances were higher than the lowest standard and the LPS level was significantly greater (p< 0.05) than the PBS control. Statistical analysis was by ANOVA with Bonferroni-Dunn (Control) post-hoc tests.

Results: Samples from 13 patients have been studied to date. Multiple assays of four of these samples showed no detectable LPS while nine of these samples resulted in both positive and negative assays. This inter-assay variability prevents measurement of the concentration of LPS in the samples. Nonetheless, many of the samples contain detectable amount of LPS. Thus, six out of eight samples from revision THA patients with aseptic loosening had positive assays, as did two of four primary TJA patients. LPS was also detected in a sample from a revision control. These results demonstrate that samples from THA patients with aseptic loosening and from primary TJA contain detectable amounts of LPS derived from Gram-negative bacteria.

Conclusion: This conclusion is consistent with numerous studies, showing that human serum contains LPS derived from minor infections, gut flora, or dental procedures. It is likely that many of these samples also contain molecules derived from Gram-positive bacteria that have very similar biological effects as LPS. However, detection of these Gram-positive molecules await further improvements in assay specificity and sensitivity.

Introduction: The treatment with epidural steroids and local anaesthetic for radicular pain arising from nerve root compression is a commonly utilised and recognised treatment. The aim of this study is to determine the efficacy of CT-guided injection of epidural steroids without anaesthetic for radicular pain but without clinical neurology in the presence of a degenerative of lytic spondylolisthesis and concomitant foraminal narrowing.

Method: The study subjects, 21 in total, were selected over a 1-year period by the surgeon. All patients had either degenerative or lytic spondylolisthesis as determined by CT, MRI and plain film and were suffering from radicular pain – sharp, shooting and burning in the L5 or S1 dermatome. For inclusion, there had to be no associated evidence of nerve root compression. All patients completed, prior to epidural therapy, a pain diagram, visual analogue scale (VAS) of pain severity on a scale of 1 to 10 and Oswestry Disability Index (ODI). The MRI and clinical pain picture were correlated. The level of the spondylolithesis was determined.

Highly selective CT-guided epidural steroid injection was then carried out at the level of spondylolithesis by an experienced interventional radiologist. The pain diagram, VAS of pain severity and ODI were all completed again by the subjects themselves or by telephone at 1 and 3 months after injection in the presence of an independent assessor (nurse) and then reviewed and discussed with the treating doctor. All subjects were also asked to complete a functional questionnaire.

Results: One month after injection 86% of those treated had greater than 50% radicular pain relief and from this group 72% had radicular pain reduction of greater than 80%. All had improvement in function. All of the above, confirmed that their quality of life had certainly improved. Three months after injection 76% of those treated still had a reduction in their radicular pain of greater than 50% (92% of these still had pain reduction of over 80%). Again all reported continued functional improvement.

Discussion: Despite the small sample size, this study highlights the short-term Benefit of CT-guided steroid epidural injections with symptomatic lumbosacral spondylolisthesis and spondylolysis with radicular pain. Pain can be relieved without anaesthesia. The mechanisms of pain relief are speculative.

We retrospectively reviewed 45 hip arthroplasties which were performed over a period of 20 years in 38 patients with cirrhosis of the liver. There was a high perioperative 30-day complication rate (26.7%). Advanced cirrhosis was associated with a higher risk of complications (p = 0.004) as also was increased age, a high level of creatinine, a low level of albumin, a low platelet count, ascites, encephalopathy and an increased operative blood loss. The survival of the prosthesis at five years was 77.8% and infection was a major cause of failure.

In view of the high rate of early complications and the limited longevity of the prosthesis, surgeons who perform hip arthroplasty on such patients should counsel them appropriately preoperatively.

We report the results of seventy-six Harris Galante Porous Cups (HGP 1) in sixty-three patients treated by Total Hip Arthroplasty (THA) with a diagnosis of avascular necrosis (AVN) of the femur (grade III and IV). The cups were inserted between 1986 and 1994 and followed prospectively. Seventy hips with a follow up of more than five years (mean 7.6 years) were reviewed.

At last review the mean Harris Hip Score was 94 (standard deviation (& dcl001;) .8), preoperatively the mean had been 29 (& dcl001;14.7). Radiographically there was no evidence of acetabular migration. The revision rate of the femoral prosthesis was 8.6%, however only three stems (4.3%) were revised for loosening the rest being revised to allow down sizing of the femoral head. The revision rate for the acetabular prosthesis was 7.1%, (five cups). At the time of revision none of the cups were clinically loose and only required the liner to be changed. The complication rate was low with no deep infections or dislocations and only nine hips, (11.8%) with grade III heterotopic ossification. Survival analysis for both stem and cup at 8 years is 96.3% (confidence interval 91 – 100%), with a worst-case survival of 93.6%, (C.I 87.4 – 99.9%)

Previous studies of patients undergoing cemented THA for the treatment of advanced AVN have reported a high incidence of component loosening. This study shows good medium term results using the Harris Galante Porous cup for acetabular reconstruction with cemented femoral components for the treatment of this difficult problem.

There are several techniques for the accurate measurement of the migration of components after arthroplasty some of which require the operative placement of tantalum balls. We have reviewed the position and migration of these markers in 64 patients after total hip arthroplasty.

In 40% of cases, one or more balls was seen to be outside the proximal femur on the postoperative radiograph, although all were considered to be within the bone at operation. In two hips, one ball appeared to have migrated towards the joint, although none was seen within the joint. Misplacement was not related to the experience of the surgeon or the operative approach.

Migration analysis which necessitates the insertion of tantalum balls requires careful technique to avoid a potential source of third-body wear. It should probably be used only for research in small series of patients.