METHODS

Healthy chondrocytes were isolated from the articular cartilage of six femoral heads, obtained with ethical permission after operations following neck of femur fractures. Chondrocytes were cultured for 5 weeks in 4 separate groups: without treatment (control culture); with 2.5ng/ml IL-1b and 2.5ng/ml oncostatin M (IL-1b+OSM); with 1.0mM BAY alone; and IL-1b+OSM+BAY. Total RNA and genomic DNA were extracted from each sample. Gene expression of IL1B was determined by SybrGreen-based qRT-PCR. The % DNA methylation at a specific CpG site in the IL1B promoter (which had previously been identified as a crucial CpG site) was quantified after bisulfite modification with a pyrosequencer (Biotage). The data for IL1B expression and % DNA methylation were analyzed in Microsoft Excel using Wilcoxon's signed rank test. P values < 0.05 were considered significant.

RESULTS

Although there was considerable variation between samples, expression of IL1B was increased by > 1000 fold in the IL-1b+OSM group compared with control culture, confirming previous results. When BAY was present together with IL-1b+OSM, the increase in IL1B expression was reduced from ∼1000-fold to ∼200-300-fold (P< 0.01). In addition, the % DNA methylation had changed. At the -299 CpG site of IL1B promoter the % methylation was 57% in control culture and 60% in the BAY alone group. IL-1b+OSM caused a decrease to 37% (P<0.01 compared with all other groups), whereas presence of BAY prevented this loss, since the % methylation was 58% in IL-1b+OSM+BAY group.

BACKGROUND

Although osteoarthritis (OA) is not an inflammatory arthritis, a characteristic feature of OA is increased production of pro-inflammatory cytokines, such as interleukin 1beta (IL-1b), by articular chondrocytes. In fact, the degree of articular inflammation is often associated with disease progression; indicating that this process probably contributes to articular damage. Suppressor of cytokine signalling (SOCS) proteins are, as the name suggests, inhibitors of cytokine signalling that function via the JAK/STAT pathway (Janus kinase/signal transducers and activators of transcription). Eight SOCS proteins, SOCS1-SOCS7 and CIS-1 (cytokine-inducible SH2-domain-1 with similar structure to the other SOCS proteins) have been identified, of which, SOCS1-3 and CIS-1 are the best characterised. Reduced expression of SOCS proteins would be predicted to result in increased cytokine responsiveness and thereby could contribute to OA pathology.

OBJECTIVES

1) To compare the expression of SOCS1-3 and CIS-1 in normal and OA human articular chondrocytes and 2) to analyze the effects of IL-1b on SOCS1-3 and CIS-1 mRNA expression.

Introduction

Primary mechanical stability is important with uncemented THR because early migration is reduced, leading to more rapid osseointegration between the implant and bone. Such primary mechanical stability is provided by the design features of the device. The aim of this study was to compare the migration patterns of two uncemented hip stems, the Furlong Active and the Furlong HAC stem; the study was designed as a randomised control trial. The implants were the Furlong HAC, which is an established implant with good long term results, and the Furlong Active, which is a modified version of the Furlong HAC designed to minimise stress concentrations between the implant and bone, and thus to improve fixation.

Materials and methods

The migration of 43 uncemented femoral components for total hip replacement was measured in a randomised control trial using Roentgen Stereophotogrammetric Analysis (RSA) over two years. Twenty-three Furlong HAC and twenty Furlong Active stems were implanted into 43 patients. RSA examinations were carried out post-operatively, and at six months, 12 months and 24 months post-operatively. The patients stood in-front of a purpose made calibration frame which contained accurately positioned radio-opaque markers. From the obtained images, the 3-D positions of the prosthesis and the host bone were reconstructed. Geometrical algorithms were used to identify the components of the implant. These algorithms allowed the femoral component to be studied without the need to attach markers to the prosthesis. The migration was calculated relative to the femoral coordinate system representing the anterior-posterior (A-P), medial-lateral (M-L) and proximal-distal (P-D) directions respectively. Distal migration was termed subsidence.

Introduction

Therapeutic exploitation of MSCs in orthopaedics has been tempered by their scarcity within ‘gold-standard’ iliac crest bone marrow aspirate (ICBMA) and the resulting need to expand cells in vitro. This is time-consuming, expensive and results in cells with a reduced differentiation capacity. [Banfi 2000] The RIA is a device that provides continuous irrigation and suction during reaming of long bones. Aspirated contents pass via a filter, trapping bony-fragments, before moving into a ‘waste’ bag, from which MSCs have been previously isolated. [Porter 2009] We hypothesised that ‘waste’ RIA bag contains more MSCs than a standard aspirated volume of ICBMA (30 ml). We further hypothesised than a fatty solid phase within this ‘waste bag’ contains many MSCs trapped within the adipocyte-rich stromal network and hence requiring an enzymatic digestion for their efficient release [Jones 2006].

Methods

The discarded filtrate ‘waste’ bag that contained saline from marrow cavity irrigation procedure from RIA reaming (7 patients) was filtered (70μm) and the solid fraction digested for 60min (37oC) with collagenase. MSC enumeration was performed using the colony-forming-unit-fibroblast (CFU-F). Following culture in standard expansion media, passage 2 cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages and their phenotype was assessed using flow cytometry. ICBMA from the same patients was used as controls.

Introduction

The use of platelet-rich concentrate (PRC) to enhance the healing response in tendon repair is currently an area of considerable interest. Activated platelets release a cocktail of growth factors and ECM regulating molecules. Previous work suggests that tenocytes are activated by contact with these clot-derived molecules. Our studies on tenocytes and PRC aim to establish the direct molecular and functional effects of PRC on tenocytes and to support the clinical research on Achilles tendon repair taking place within our group. We hypothesise that applying PRC to human tenocytes in culture will increase proliferation rate and survival by activating relevant signalling pathways.

Materials and Methods

Using a centrifugation method, PRC was extracted from fresh human whole blood. The PRC was immediately clotted and left in medium overnight to release biological factors (at least 95% of presynthesized growth factors are secreted in the first hour of activation)¹. Human tenocytes derived from explanted healthy hamstring were used for up to three passages. Cells were treated with varying concentrations of PRC-conditioned medium and assessed for viable cell number (Alamar Blue™ fluorescence) and proliferation (Ziva™ Ultrasensitive BrdU assay) after 72hrs. For western blotting, cells were treated with 10% PRC for 5 or 30 minutes. Antibodies to P-ERK and P-Akt detected the active protein state on the blot, followed by membrane stripping and re-probing with pan antibodies. Quantification was achieved by densitometry using Visionworks software v. 6.7.1.

Introduction

Both the RANK/RANKL system and the endocannabinoid system have roles in bone remodelling. Activation of CB1 receptors on sympathetic nerve terminals in trabecular bone modulates bone remodelling by attenuating adrenergic inhibition over bone formation. CB2 receptors are involved in the local control of bone cell differentiation and function. Osteoblastic CB2 receptor activation negatively regulates RANKL mRNA expression indicating an interaction between the two systems and that efficient bone remodelling requires a balance between these two systems. The aim of the study was to establish the presence of the different components of the endocannabinoid system and the RANK/RANKL signalling pathway in human bone and osteoclast culture.

Methods

Levels of endocannabinoids (AEA, 2-AG) and their related compounds (OEA, PEA) in human trabecular bone, obtained from patients undergoing elective orthopaedic surgery, were measured using Liquid Chromatography Mass Spectrometry (LC-MS-MS). mRNA for the endocannabinoid synthetic and catabolic enzymes (NAPE-PLD, DAGLa, FAAH, MAGL), cannabinoid-activated receptors (CB1, CB2, PPARs, TRPV1), and RANK, RANKL and NFkB were determined using Taqman Real-Time PCR. Osteoclasts were differentiated from U-937 cells (Human leukaemic monocyte lymphoma cell line), following the sequential treatment using TPA (0.1μg/ml) followed by either TNF-a (3ng/ml) or calcitriol (10⁻⁸M), cultured for up to 30 days. Osteoclasts were identified by positive staining with tartrate resistant acid phosphatase (TRAP), multinucleation and the ability to form resorption pits on calcium phosphate coated discs. Taqman Real-Time PCR was performed to detect the expression of the osteoc!

last marker genes TRAP and cathepsin K, together with genes of the endocannabinoid and RANK/RANKL signalling pathways.

Osteoarthritis (OA)

is the most common arthritic condition. OA causes joint pain, loss of mobility and significantly affects the quality of life for the affected individual. The major burden to patients with arthritis is pain. However, often radiological joint destruction and the extent of pain do not correlate. This causes a dilemma for clinicians in advising timing for joint replacement surgery. In arthritis, concentrations of the neurotransmitter, glutamate is increased within the synovial fluid activating both peripheral pain mechanisms and pathological processes (1). Other pathological/pain related metabolites are also released into synovial fluid, which provides a real time snap shot of the joint pathology. We have tested the hypothesis that ‘The increased levels of pain and disease-related metabolites within human synovial fluids from arthritic joints can be detected and quantified ex vivo using high resolution 1H-NMR.’

Method

OA synovial fluid samples were obtained during arthroscopy or total knee replacements from patients with varying degrees of pain and pathology (cartilage graded 0-4; n=21). Pain perception was determined using the Oxford knee score and samples sub-classified as mild, moderate and severe pain. All samples were analysed using 500 MHz 1H NMR spectroscopy. Chemical shifts were referenced to a known concentration NMR internal standard (TSP), peaks identified by reference to published synovial fluid NMR spectra (2) and peak integrals measured using the Bruker software Topspin 2.0.

Results: Using NMR we were able to detect around 26 metabolite-specific peaks in synovial fluid spectra (such as glutamate/glutamine, isoleucine, acetyl glucoproteins, beta-hydroxbutyrate, CH2 lipids, lactate, glucose). Some specific metabolites varied significantly with pain or pathological score. For example, we found significantly more glutamate/glutamine, isoleucine and beta-hydroxybutyrate (p<0.05, T test) in OA samples reporting mild to moderate levels of pain (n=14) compared to severe pain (n=7). Significantly more CH2 lipids (p<0.05, T-test) were also present in samples indicating severe pain compared to mild/moderate pain.

Background/Study Aim

Injectable scaffolds which also deliver cells and bioactive molecules to augment bone healing overcome many of the limitations associated with current bone graft substitutes. The aim of this study was to develop and test a novel injectable scaffold that self-assembles isothermically in situ to form a biodegradable porous osteoconductive material, and to assess the viability of human mesenchymal stem cells (hMSC) seeded onto the scaffold.

Methods

Rheological assessment was performed on three different molecular weights (Mw) of poly(lactic-co-glycolic acid) (PLGA) (26kDa, 53kDa and 92kDa) combined with differing ratios of polyethylene glycol (PEG) to control the temperature required for scaffold self-assembly. The strength (MPa) and stiffness (Young's Modulus) patterns of the scaffolds were assessed in compression. The cell viability, proliferation and distribution patterns of hMSCs seeded within the scaffold were assessed through various assays (Alamar Blue), confocal microscopy and micro-CT. The hMSC differentiation in osteogenic media was characterised by the identification of specific bone formation markers (e.g. alkaline phosphatase).

Introduction

The biological response to UHMWPE particles generated by total joint replacements is one of the key causes of osteolysis, which leads to late failure of implants. Particles ranging from 0.1-1.0μm have been shown to be the most biologically active, in terms of osteolytic cytokine release from macrophages [1]. Current designs of lumbar total disc replacements (TDR) contain UHMWPE as a bearing surface and the first reports of osteolysis around TDR in vivo have appeared recently in the literature [2]. The current wear testing standard (ISO18192-1) for TDR specifies only four degrees of freedom (4DOF), i.e. axial load, flexion-extension, lateral bend and axial rotation. However, Callaghan et al. [3] described a fifth DOF, anterior-posterior (AP) shear. The aim of this study was to investigate the effect that this additional AP shear load component had on the size and morphology of the wear particles generated by ProDisc-L TDR devices over five million cycles in a spine simulator.

Methods

A six-station lumbar spine simulator (Simulation Solutions, UK) was used to test ProDisc-L TDR components (Synthes Spine, USA) under the ISO 18192-1 standard inputs and with the addition of an AP load of +175 and −140N. Wear particles were isolated at 2 and 5 mc using a modified alkaline digestion protocol [4]. Particles were collected by filtration and imaged by high resolution FEGSEM. Particle number and volume distributions were calculated as described previously [4] and were compared statistically by one way ANOVA (p<0.05).

Introduction

Unicompartmental Knee Replacement (UKR) is an appealing alternative to Total Knee Replacement (TKR) when the patient has isolated compartment osteoarthritis (OA). A common observation post-operatively is radiolucency between the tibial tray wall and the bone. In addition, some patients complain of persistent pain following implantation with a UKR; this may be related to elevated bone strains in the tibia. The aim of this study was to investigate the mechanical environment of the tibia bone adjacent to the tray wall, following UKR, to determine whether this region of bone resorbs, and how altering the mechanical environment affects tibia strains.

Materials and methods

A finite element (FE) model of a cadaver tibia implanted with an Oxford UKR was used in this study, based on a validated model. A single static load, measured in-vivo during a step-up activity was used. There was a 1 mm layer of cement surrounding the keel in the cemented UKR, and the cement filled the cement pocket. In accordance with the operating procedure, no cement was used between the tray wall and bone. For the cementless UKR a layer of titanium filled the cement pocket. An intact tibia was used to compare to the cemented and cementless UKR implanted tibiae. The tibia was sectioned by the tray wall, defining the radiolucency zone (parallel to the vertical tray wall, 2 mm wide with a volume of 782.5 mm³), corresponding to the region on screened x-rays where radiolucencies are observed. Contact mechanics algorithms were used between all contacting surfaces; bonded contact was also introduced between the tray wall and adjacent bone, simulating a mechanical tie between them. Strain energy density (SED), was compared between the intact and implanted tibia for the radiolucency zone. Equivalent strains were compared on the proximal tibia between the intact and implanted tibia models. Forty patients (20 cemented, 20 cementless) who had undergone UKR were randomly selected from a database, and assessed for radiolucency.

INTRODUCTION

Osteoarthritis (OA) can be artificially simulated ex vivo on healthy articular cartilage (AC) samples by use of proteolytic enzymes. In this article we will present preliminary analyses of the physical degradation of AC when subjected to alternating mechanical stresses. Since AC damage due to OA is believed to be mechanically induced, the first step towards the realisation of an improved understanding of degenerative behaviour of AC under physiological loading conditions is to perform ex vivo tests which mimic such conditions at best.

METHODS

Porcine AC was subjected to biochemical stimulation or left as native AC. Biochemical degradation was performed using combinations of trypsin and Matrix Metalloproteinases (MMPs) to induce the loss of proteoglycan and collagen. A comparison of the biochemical and mechanical properties, topography and difference in response to mechanical damage between the digested AC and healthy AC was made using White Light Interferometry (WLI), Atomic Force Microscopy (AFM) and mechanical testing. The mechanical damage was induced by subjecting AC to shear under physiological and non physiological conditions. The AC was mechanically tested in a Phosphate Buffered Saline (PBS) bath. After mechanical testing, biochemical analysis of the collagen and aggrecan content of the tissue and PBS present in the bath during the mechanical test was performed. Collagen content was determined by measurement of the amount of hydroxyproline (HPRO), and aggrecan content by the amount of glycosaminoglycans (GAG). The mechanical test was either performed on healthy (native) AC or on AC which had first been digested.

INTRODUCTION

Bone marrow derived mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. Hypoxia has been shown to improve chondrogenesis in adult stem cells. In this study we characterised bone marrow derived stem cells and investigated the effects of hypoxia on gene expression changes and chondrogenesis.

MATERIALS AND METHODS

Adherent colony forming cells were isolated and cultured from the stromal component of bone marrow. The cells at passage 2 were characterised for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium under normoxic (20% oxygen) or hypoxic (5% oxygen) conditions for 14 days. Gene expression analysis, glycosoaminoglycan and DNA assays, and immunohistochemical staining were determined to assess chondrogenesis.

Purpose

To identify genes showing altered expression in osteoarthritic (OA) cartilage and synovium. Dkk3, a member of the Dickoppf family of Wnt signalling inhibitors was overexpressed and this work highlights the potential function of Dkk3 in OA.

Methods

Real-time PCR was used to compare the expression of 270 cytokines, chemokines and their receptors in cartilage and synovium from OA and non-OA patients. Expression of Dkk3 was also measured in ATDC5 cells and in bovine nasal cartilage (BNC) explants treated with inflammatory cytokines. The effect of Dkk3 on hydroxyproline and GAG release was measured in BNC explant cultures.

To assess the distribution of Dkk3 in OA cartilage immunohistochemistry was carried out on anteromedial gonarthrosis specimens. The level of Dkk3 in synovial fluid tricompartmental and unicompartmental cartilage lesions was measured using ELISA.

Introduction

P-15 (GTPGPQGIAGQRGVV), a fifteen residue synthetic peptide, is a structural analogue of the cell binding domain of Type 1 collagen and creates a biomimetic environment for bone repair when immobilized on anorganic bovine mineral (ABM) scaffolds. ABM-P-15 scaffolds have been shown to enhance bone marrow stromal cell growth and differentiation. This study aimed at evaluating the osteogenic potential of human dental pulp stromal cells (HDPSCs) compared to human bone marrow stromal cells (HBMSCs) in monolayer and on 3D ABM-P-15 scaffolds in vitro and in vivo.

Materials and Methods

HDPSCs and HBMSCs were cultured as monolayers in basal or osteogenic media for 3 weeks. Osteogenic differentiation was confirmed using alkaline phosphatase (ALP) staining and ALP specific activity (ALPSA). In addition, the presence and distribution of osteogenic markers including Type 1 collagen, bone sialoprotein (BSP), osteopontin (OPN) and osteocalcin (OCN) was determined by immunohistochemisty. Gene expression for COL1, RUNX2 and OCN was determined using RT-PCR after 1, 3 and 5 weeks in basal culture. For 3D culture, HDPSCs were seeded on ABM scaffolds ± P-15 (CeraPedics LLC) and cultured in basal media for 6 weeks. Cell viability and growth were visualized by confocal and scanning electron microscopy. Osteogenic differentiation was confirmed by ALP staining and ALPSA. For in vivo studies, HDPSCs were injected and sealed in diffusion chambers containing ABM-P-15 or ABM alone which were then implanted intraperitoneally in nude mice for 8 weeks. The retrieved samples were then processed for histology.

Introduction

Local anaesthetic has been reported to have a potentially detrimental effect on human chondrocytes both in vitro and in vivo. Due to chondroproliferative effects, magnesium may be an alternative intra-articular analgesic agent following arthroscopy. We aimed to examine the dose response effect of commonly used local anaesthetics on chondrocyte viability and also to report on the effect of adding magnesium to the local anesthetic agent.

Methods

Human chondrocytes were grown under standard culture conditions. Cells were exposed to either lignocaine (0.5, 1, 2%), levobupivacaine (0.125, 0.25, 0.5%), bupivacaine (0.125, 0.25, 0.5%) or ropivacaine (0.1875, 0.375, 0.75%) for 15 minutes. Cells were also exposed to a local anesthetic agent with the addition of magnesium (10, 20, or 50%). Cells exposed to culture media or saline served as controls. The MTS assay was used to assess cell viability 24 hours after exposure. One-way ANOVA were used to test for statistical significance.

In conclusion

we have shown that ES waveforms enhanced osteoblast activity to different extent but importantly demonstrate for the first time that DW stimulation has a greater effect on differentiation and mineralisation of osteoblasts than CC stimulation. DW stimulation has potential to provide a secure, controlled and effective application for bone healing. These findings have significant implications in the clinical management of fracture repair and bone

non-unions.

Introduction

Recovery of muscle strength following Total Knee Replacement (TKR) is variable, and can affect the resultant function of the patient. Satellite cells are undifferentiated myogenic precursors considered to be muscle stem cells that lie quiescently around the muscle fibre. These cells repair damaged fibres and have the potential to generate new muscle fibres. Therefore, theoretically, they could be associated with the variation in muscle recovery following surgery. We hypothesised that the recovery of muscle strength following knee replacement in a given patient would be influenced by the underlying number of satellite cells in that patient.

Methods

20 patients undergoing TKR were recruited from the waiting list of a single consultant. A muscle biopsy was taken at the time of surgery from the distal quadriceps. This was fixed in paraffin wax, and sections obtained. Satellite cells were identified with a primary mouse antibody for Pax7 - a cytoplasmic protein marker - and an immunofluorescent goat anti-mouse secondary. Slides were counterstained with DAPI to stain the myonuclei. The positive staining index (PSI) was calculated (number of satellite cells/total number of myonuclei x 100). Recovery of muscle (quadriceps) strength was assessed using the leg extensor power-rig (LegRig) pre-operatively, at 6 and 26 weeks post-operatively. Statistical analysis was performed using the Minitab version 15 software, the level of significance was set as p = 0.05.

Introduction

The annual incidence of fractures in the UK is almost 4%. Bone grafting procedures and segmental bone transport have been employed for bone tissue regeneration. However, their limited availability, donor site morbidity and increased cost mean that there is still a large requirement for alternative methods and there is considerable research into regeneration using bone morphogenetic proteins (BMPs). The aims of this study are to synthesise and combine BMP-2 with a novel nanocomposite and study its release.

Materials and Methods

BMP-2 was synthesised using an E. coli expression system and purified. C2C12 cells were used to test its bioactivity using an alkaline phosphatase (ALP) assay. The modified solution evaporation method was used to fabricate 30% a-TCP/PLGA nanocomposite and it was characterized using SEM, TEM, TGA, XRD, EDX and particle size analysis. The release pattern of adsorbed BMP-2 was studied using an ELISA assay.

Introduction

Anteromedial gonarthrosis is a common well described pattern of knee osteoarthritis with cartilage wear beginning in the anteromedial quadrant of the medial tibial plateau in the presence of an intact and functioning ACL. It is well known that mechanical factors such as limb alignment and meniscal integrity affect the progression of arthritis and there is some evidence that the morphology of the tibial plateau may be a risk factor in the development of this disease. The extension facet angle is the angle of the downslope of the anterior portion of the medial tibial plateau joint surface in relation to the middle portion on a sagittal view. If this is an important factor in the development of AMG there may be potential for disease modifying intervention.

This study investigates if there is a significant difference in this angle as measured on MRI between a study cohort with early AMG (partial thickness cartilage damage and intact ACL) and a comparator control cohort of patients (no cartilage damage and ACL rupture).

Methods

3 Tesla MRI scans of 99 patients; 54 with partial thickness cartilage damage and 44 comparitors with no cartilage damage (acute ACL rupture) were assessed. The extension facet angle was measured (Osirix v3.6) using a validated technique on two consecutive MRI T2 sagittal slices orientated at the mid-coronal point of the medial femoral condyle. (InterClass Correlation 0.95, IntraClass Correlation 0.97, within subject variation of 1.1° and coefficient of variation 10.7%). The mean of the two extension angle values was used. The results were tabulated and analysed (R v2.9.1).

AIM

Avascular necrosis (AVN) of the femoral head is a potentially debilitating disease of the hip in young adults. Impaction bone grafting (IBG) of morcellised fresh frozen allograft is used in a number of orthopaedic conditions. This study has examined the potential of skeletal stem cells (SSC) to augment the mechanical properties of impacted bone graft and we translate these findings into clinical practice.

STUDY DESIGN

We have examined the effect of SSC density on augmentation of bone formation. An in vitro model was developed to replicate the surgical IBG process. Plain allograft was used as the control, and the SSC's seeded at a density of 5×103, 5×104 and 2×105 cells per cc of allograft for the experimental groups. All samples were cultured for 2 weeks and mechanically tested to determine shear strength using the Mohr Coulomb failure curve. The approach was translated to 3 patients with early avascular necrosis (AVN) of the femoral head. The patient's bone marrow was concentrated in theatre using a centrifugation device and the concentrated fraction of SSC's were seeded onto milled allograft. The patient's necrotic bone was drilled, curetted and replaced with impacted allograft seeded with SSC's. Osteogenic potential of concentrated and unconcentrated marrow was simultaneously compared in vitro by colony forming unit assays.

Introduction

Ischaemic preconditioning (IPC) is a phenomenon whereby a tissue is more tolerant to an insult if it is first subjected to short bursts of sublethal ischaemia and reperfusion. The potential of this powerful mechanism has been realised in many branches of medicine where there is an abundance of ongoing research. However, there has been a notable lack of development of the concept in Orthopaedic surgery. The routine use of tourniquet-controlled limb surgery and traumatic soft tissue damage are just two examples of where IPC could be utilised to beneficial effect in Orthopaedic surgery.

Methods

We conducted a randomized controlled clinical trial looking at the role of a delayed remote IPC stimulus on a cohort of patients undergoing a total knee arthroplasty (TKA). We measured the effect of IPC by analysing gene expression in skeletal muscle samples from these patients. Specifically we looked at the expression of Heat shock protein-90 (HSP-90), Catalase and Cyclo-oxygenase-2 (COX-2) at the start of surgery and at one hour into surgery. Gene analysis was performed using real time polymerase chain reaction amplification. As a second arm to the project we developed an in-vitro model of IPC using a human skeletal muscle cell line. A model was developed, tested and subsequently used to produce a simulated IPC stimulus prior to a simulated ischaemia-reperfusion (IR) injury. The effect of this on cell viability was investigated using crystal violet staining.

Objective

Human bone marrow stromal cells (HBMSCs) are multipotent and can form bone, cartilage or other tissues under different inductive conditions. The aim of this study was to investigate the effects of enamel matrix derivative (EMD) on the growth and osteogenic differentiation of HBMSCs.

Methods

HBMSCs were cultured in monolayer with EMD (1, 10, 50,100, 250μg/ml) in aMEM supplemented with 2% FBS for 3 days. Cells cultured in aMEM supplemented with 2% FBS (basal medium) served as the control group. Double-stranded DNA was quantified by PicoGreen assay. Quantitative RT-PCR was performed to determine the expression levels of RUNX2, osteopontin (OPN) and osteocalcin (OCN), dentin matrix protein1 (DMP1) and dentin sialophosphoprotein (DSPP) at different time points (day 0, 5 and 10) when exposed to 10μg/ml EMD or basal medium. Alkaline phosphatase specific activity (ALPSA) was determined after 5 and 10 days culture. Mineral deposition (as calcium) was visualised using Alizarin Red staining.

Background

Osteoarthritis (OA), is characterised with a loss of cartilage and pain in affected joints. It is this pain which most patients associate with their condition. Intra-articular (IA) hyaluronan (HA) has been shown to reduce the pain associated with OA both in animal models and in clinical trials. There are purified HA available and in recent years hyaluronan hydrogels, where the material has been cross-linked into networks, have become available. One of these cross-linked HA hydrogels is Durolane¯. This study has sought to evaluate the effect of Durolane in an in vivo model of osteoarthritis.

Methods

Mice (C57BL/6, 12 weeks) were obtained from Jackson Labs and all protocols were approved by Rush IACUC. Joint injury was initiated by TGFb1 injection as described [1]. Mice were given IA injections of 200 ng TGFb1, at days 1 and 3 delivered in a 6 ul volume into the rear right knee joint only. Twenty four hours after the second injection of TGFb1 10 ul of Durolane was injected into the same knee joint. All animals were exercised daily on a treadmill to induce tissue degeneration. Three groups of animals were evaluated: Naïve (n = 4), TGFb1 + saline (n = 5) and TGFb1 + Durolane (n = 5). Running performance was monitored daily and 15 days post injections, gait was assessed quantitatively using the TreadScan gait analysis system (CleverSys).

Background

Following an anterior cruciate ligament (ACL) injury, the affected knee is known to experience bone loss and is at significant risk of becoming osteoporotic. Surgical reconstruction is performed to attempt to restore the function of the knee and theoretically restore this bone density loss. Cross-sectional analysis of the proximal tibia using peripheral quantitative computed tomography (pQCT) enables localised analysis of bone mineral density (BMD) changes. The aim of this study was to establish the pattern of bone density changes in the tibia pre- and post- ACL reconstruction using pQCT image analysis.

Methods

Eight patients who underwent ACL reconstruction were included. A cross sectional analysis of the proximal tibia was performed using a pQCT scanner pre-operatively and one to two years post-operatively on both the injured and contralateral (control) knee. The proximal two and three percent slices [S2 and S3] along the tibia were acquired. These were exported to Matlab(tm) and automated segmentation was performed to remove the tibia from its surrounding structures. Cross correlation was applied to co-register pairs of images and patterns of change in BMD were mapped using a t-test (p<0.05). Connected components of pixels with significant change in BMD were created and used to assess the impact of ACL injury & reconstruction on the proximal tibial BMD.

Method

Synovial fluid samples have been obtained during arthroscopy or knee replacement from patients with varying degrees of joint pathology (cartilage graded 0-4; meniscal tears classified as acute or degenerative). Samples were also taken from patients undergoing Anterior Cruciate Ligament (ACL) reconstruction with no additional pathology. Samples were analysed using 500 MHz 1H NMR spectroscopy. Chemical shifts were referenced to known concentration NMR internal standard (TSP), peaks identified by reference to published synovial fluid NMR spectra (1) and peak integrals measured using the Bruker software Topspin 2.0.

Results

Spectroscopy revealed a number of differences in metabolites between OA, meniscal tear and ACL pathologies. These included significantly increased concentrations of glutamate, n-acetyl glycoprotein and β-hydroxybutyrate in OA (n=10) and acute meniscal tears (n=6) compared to ACL samples (p<0.05, T-test, n=6). Specific metabolites were also able to discriminate between OA with no meniscal tear and OA with meniscal tear synovial fluids. For example, concentrations of n-acetyl glycoproteins, glutamate and CH3 lipids were significantly increased in OA without tears (n=10) compared to OA plus meniscal tears (n=12); conversely ceramide concentrations were significantly increased in OA plus tears compared to OA only samples (p<0.05, T-test).

Materials and methods

MBG was prepared using femoral heads donated from patients undergoing total hip replacement surgery using a bone mill in a standard manner. Non porous HA (npHA) was prepared using a precipitation method of Calcium Carbonate and Orthophosphoric acid. The porous HA, (pHA) is a 60% macroporosity HA commercially prepared.

Chamber

The uniaxial compression chamber was a 30mm diameter, steel chamber. Holes were drilled to allow fluid drainage. Loads were applied using a 10 kN load cell. Specimens were prepared in the volumetric proportions pure HA, pure MBG, 2:1, 1:1, 1:2 ratio of MBG to HA. The samples were subjected to compressive forces of incrementally increasing loads of up to 2 KN for 60 cycles. The sample was then allowed to creep under a stress of 2 kN. MBG was also tested up to forces of 7 kN. The mechanical parameters that were examined were the stiffness of the sample at the 60th cycle, (Ec60), and creep

Background

Deep infection rates of 1 - 2% following primary hip and knee arthroplasty are mainly due to endogenous contamination of the surgical site from bacteria within the patient's own skin. However surgical skin preparation removes only bacteria from the surface of the skin, leaving viable bacteria in the deeper layers of the skin within hair follicles and sweat and sebaceous glands. The aim of our study was to test the hypothesis that surface skin swabs taken after skin preparation with alcoholic povidone iodine would not grow bacteria, whereas full thickness biopsies taken from the line of surgical incision would grow bacteria.

Methods

Under LREC approval, informed consent was obtained from 22 patients undergoing primary hip (n=9) or knee (n=13) arthroplasty. All patients received intravenous antibiotic prophylaxis at the time of induction of anaesthesia. After surgical skin preparation with alcoholic povidone iodine, a surface skin swab and full thickness skin biopsy, using an 8mm x 4 mm elliptical punch, were taken. The swab culture was incubated aerobically and anaerobically at 37°C. The skin biopsy was cut aseptically in half. One half was crushed using artery forceps, placed in 5mL anaerobe basal broth and incubated anaerobically at 37°C. The other half of the skin biopsy was frozen in isopentane and gram – stained after sectioning.

Introduction

Iliac crest bone marrow aspirate (ICBMA) is frequently cited as the ‘gold-standard’ source of MSCs. MSCs have been shown to reside within the intramedullary (IM) cavities of long-bones [Nelea, 2005] however a comparative assessment with ICBMA has not yet been performed and the phenotype of the latter compartment MSCs remains undefined in their native environment.

Methods

Aspiration of the IM cavities of 6 patients' femurs with matched ICBMA was performed. The long-bone-fatty-bone-marrow (LBFBM) was filtered (70μm) to separate liquid and solid fractions and the solid fraction was briefly (60min, 37oC) digested with collagenase. MSC enumeration was performed using the colony-forming-unit-fibroblast (CFU-F) assay and quantification of cells with the CD45low CD271+ phenotype by flow-cytometry. [Jones 2002, Buhring 2007] MSCs were cultured and standard expansion media and passage 2 cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages.

Background

Osteoarthritis (OA) is a degenerative, chronic disease of the articular cartilage that affects more than 150 million people [1]. In the knee, OA can begin as either isolated medial OA or isolated lateral OA. Previous research [2,3] shows medial OA and lateral OA have characteristic cartilage lesion locations and progression patterns as well as flexion angles associated with lesion development, indicating strong involvement of mechanical factors in disease initiation. Therefore, it is important to investigate these mechanical factors. Previous studies combined data sets (geometry, motion, load) from separate sources. The aim of the current work was to use a consistent multi-modal approach.

Method

A finite element (FE) model of a healthy knee in full extension was created using magnetic resonance imaging (MRI) and motion analysis data from the same subject (female, 24 yrs). MRI data was obtained using a 3T MRI scanner (Philips Medical Systems/Achieva). Surface geometries of the tibia, femur, and associated cartilage were then semi-automatically segmented and processed (Mimics 12.5; Geomagic Studio 11; SolidWorks 2009). Motion data was collected at 100 Hz (Vicon 612) during level walking and subsequently applied to a lower limb model (AnyBody Version 3.0) to calculate muscle forces. Both sets of data were then combined to create a subject-specific FE model (ANSYS 11.0) which was solved to determine relative contact areas, pressures, and deformations in the medial and lateral tibiofemoral compartments.

Introduction

Civilian fractures have been extensively studied with in an attempt to develop classification systems, which guide optimal fracture management, predict outcome or facilitate communication. More recently, biomechanical analyses have been applied in order to suggest mechanism of injury after the traumatic insult, and predict injuries as a result of a mechanism of injury, with particular application to the field so forensics. However, little work has been carried out on military fractures, and the application of civilian fracture classification systems are fraught with error. Explosive injuries have been sub-divided into primary, secondary and tertiary effects. The aim of this study was to 1. determine which effects of the explosion are responsible for combat casualty extremity bone injury in 2 distinct environments; a) in the open and b) enclosed space (either in vehicle or in cover) 2. determine whether patterns of combat casualty bone injury differed between environments Invariably, this has implications for injury classification and the development of appropriate mitigation strategies.

Method

All ED records, case notes, and radiographs of patients admitted to the British military hospital in Afghanistan were reviewed over a 6 month period Apr 08-Sept 08 to identify any fracture caused by an explosive mechanism. Paediatric cases were excluded from the analysis. All radiographs were independently reviewed by a Radiologist, a team of Military Orthopaedic Surgeons and a team of academic Biomechanists, in order to determine the fracture classification and predict the mechanism of injury. Early in the study it became clear that due to the complexity of some of the injuries it was inappropriate to consider bones separately and the term ‘Zone of Insult’ (ZoI) was developed to identify separate areas of injury.

Introduction

The optimum strategy for the care of war wounds is yet to be established. A need exists to model complex extremity injury, allowing investigation of wound management options.

Aim

To develop a model of militarily relevant extremity wounding.

Introduction

Patients with knee osteoarthritis (OA) often tell us that they put extra load on the joints of the opposite leg as they walk. Multiple joint OA is common and has previously been related to gait changes due to hip OA (Shakoor et al 2002). The aim of this study was to determine whether patients with medial compartment knee OA have abnormal biomechanics of the unaffected knee and both hips during normal level gait.

Methods

Twenty patients (11 male, 9 female), with severe medial compartment knee OA and no other joint pain were recruited. The control group comprised 20 adults without musculoskeletal pain. Patients were reviewed, x-rays were examined and WOMAC and Oxford knee scores were completed. A 12 camera Vicon (Vicon, Oxford) system was used to collect kinematic data (100Hz) on level walking and the ground reaction force was recorded using three AMTI force plates (1000Hz). Surface electrodes were placed over medial and lateral quadriceps and hamstrings bilaterally to record EMG data (1000Hz). Kinematics and kinetics were calculated using the Vicon ‘plug-in-gait’ model. A co-contraction index was calculated for the EMG signals on each side of the knee, representing the magnitude of the combined readings relative to their maximum contraction during the gait cycle. Statistical comparisons were performed using t-tests with Bonferroni's correction for two variables and ANOVA for more than two variables (SPSS v16).

Background

High re-rupture rates following repairs of rotator cuff tears (RCTs) have resulted in the increased use of repair grafts to act as temporary scaffolds to support tendon healing. It has been estimated that thousands of extracellular matrix repair grafts are used annually to augment surgical repair of rotator cuff tears. The only mechanical assessment of the suitability of these grafts for rotator cuff repair has been made using tensile testing only, and compared grafts to canine infraspinatus. As the shoulder and rotator cuff tendons are exposed to shearing as well as uniaxial loading, we compared the response of repair grafts and human rotator cuff tendons to shearing mechanical stress. We used a novel technique to study material deformation, dynamic shear analysis (DSA).

Methods

The shear properties of four RCT repair grafts were measured (Restore, GraftJacket, Zimmer Collagen Repair and SportsMesh). 3mm-sized biopsy samples were taken and subjected to DSA using oscillatory deformation under compression to calculate the storage modulus (G') as an indicator of mechanical integrity. To assess how well the repair grafts were matched to normal rotator cuff tendons, the storage modulus was calculated for 18 human rotator cuff specimens which were obtained from patients aged between 22 and 89 years (mean age 58.8 years, with 9 males and 9 females). Control human rotator cuff tendons were obtained from the edge of tendons during hemiarthoplasties and stabilisations.

A 1-way ANOVA of all of the groups was performed to compare shear properties between the different commercially available repair grafts and human rotator cuff tendons to see if they were different. Specific comparison between the different repair grafts and normal rotator cuff tendons was done using a Dunn's multiple comparison test.

INTRODUCTION

Motion analysis is routinely used in the clinical and research sectors to quantify joint biomechanics. It plays an important role in clinical assessments by aiding the physician to distinguish between primary movement abnormalities and any secondary compensatory mechanisms that may overshadow the cause of the problem. During a data collection session, a wealth of biomechanical data regarding joint and segment kinematics and kinetics are collected from patients performing daily activities. Objective classification can be used to automate a diagnosis from this data and has been used previously to analyse measurements of level gait [1]. It is of interest to assess the knee during stair-gait as this activity involves greater range of motion (ROM) of the lower limbs, larger forces and moments acting at the knee.

AIM

The aim of the current study is to explore the use of an objective classifier [1] to characterise knee osteoarthritis (OA) and monitor functional recovery following a total knee replacement (TKR) using measurements from stair-gait.

INTRODUCTION

Useful feedback from a Total Knee Replacement (TKR) can be obtained from post-surgery in-vivo assessments. Dynamic Fluoroscopy and 3D model registration using the method of Banks and Hodge (1996) [1] can be used to measure TKR kinematics to within 1° of rotation and 0.5mm of translation, determine tibio-femoral contact locations and centre of rotation. This procedure also provides an accurate way of quantifying natural knee kinematics and involves registering 3D implant or bone models to a series of 2D fluoroscopic images of a dynamic movement.

AIM

The aim of this study was to implement a methodology employing the registration methods of Banks and Hodge (1996) [1] to assess the function of different TKR design types and gain a greater understanding of non-pathological (NP) knee biomechanics.

Introduction

Low back pain is a major public health problem in our society. Degeneration of intervertebral disc (IVD) appears to be the leading cause of chronic low-back pain [1]. Mechanical stimulations including compressive and tensional forces are directly implicated in IVD degeneration. Several studies have implicated the cytoskeleton in mechanotransduction [2, 3], which is important for communication and transport between the cells and extracellular matrix (ECM). However, the potential roles of the cytoskeletal elements in the mechanotransduction pathways in IVD are largely unknown.

Methods

Outer annulus fibrosus (OAF) and nucleus pulposus (NP) cells from skeletally mature bovine IVD were either seeded onto Flexcell¯ type I collagen coated plates or seeded in 3% agarose gels, respectively. OAF cells were subjected to cyclic tensile strain (10%, 1Hz) and NP cells to cyclic compressive strain (10%, 1Hz) for 60 minutes. Post-loading, cells were processed for immunofluorescence microscopy and RNA extracted for quantitative PCR analysis.

Introduction

The treatment of distal femoral fractures has undergone several changes during the past century, from non-operative techniques to more recently minimally-invasive internal fixation. The Less Invasive Stabilisation System (LISS) is an internal fixation plate that combines closed fixation of the distal femur using an anatomically pre-contoured plate with locked unicortical screws.

Study aim

The purpose of this multicentre study was to review the use of the LISS plate in three regional centres with respect to fracture healing between different severities of fractures.

Introduction

Anteromedial osteoarthritis of the knee (anteromedial gonarthrosis-AMG) is a common form of knee arthritis. In a clinical setting, knee arthritis has always been assessed by plain radiography in conjunction with pain and function assessments. Whilst this is useful for surgical decision making in bone on bone arthritis, plain radiography gives no insight to the earlier stages of disease. In a recent study 82% of patients with painful arthritis had only partial thickness joint space loss on plain radiography. These patients are managed with various surgical treatments; injection, arthroscopy, osteotomy and arthroplasty with varying results. We believe these varying results are in part due to these patients being at different stages of disease, which will respond differently to different treatments. However radiography cannot delineate these stages. We describe the Magnetic Resonance Imaging (MRI) findings of this partial thickness AMG as a way of understanding these earlier stages of the disease.

Method

46 subjects with symptomatic partial thickness AMG underwent MRI assessment with dedicated 3 Tesla sequences. All joint compartments were scored for both partial and full thickness cartilage lesions, osteophytes and bone marrow lesions (BML). Both menisci were assessed for extrusion and tear. Anterior cruciate ligament (ACL) integrity was also assessed. Osteophytes were graded on a four point scale in the intercondylar notch and the lateral margins of the joint compartments. Scoring was performed by a consultant radiologist and clinical research fellow using a validated MRI atlas with consensus reached for disagreements. The results were tabulated and relationships of the interval data assessed with linear by linear Chi2 test and Pearson's Correlation.

Study groups

The study consisted of four experimental groups: 1)Pure MBG, force of 1.98 kN 2)Pure MBG, force 3.63kN. 3)1:1 mixture of MBG: porous HA (pHA), 4)1:1 mixture MBG: non porous HA (npHA). 6 samples of each group were performed.

Endurance testing

The potted femur was loaded in a manner representing the walking cycle (1.98kN) at 1 Hz for 50 000 cycles. The displacement of the femoral head during loading was measured by two displacement transducers (LVDT) were mounted on aluminum brackets to measure vertical displacement and rotation.

Introduction

Open fractures occur with an annual incidence of 11.5 per 100,000 (6900 pa in UK). Infection rates, even with intravenous broad-spectrum antibiotics, remain as high as 22%. For this reason necessary bone grafting is usually delayed until soft-tissue cover of the bone injury is achieved. A biodegradable bone graft that released sustained high concentrations of antibiotics and encouraged osteogenesis, that could be implanted safely on the day of injury would reduce infection rates and avoid reoperation and secondary grafting. The non –union rate (approx 350 pa in UK) should also be reduced. Such a graft, consisting of a PLA/PGA co –polymer and containing antibiotics, is under development and here we report assessment of spectrum and duration of antimicrobial activity and effect of addition of antibiotics on mechanical properties.

Methods

Varying concentrations of gentamicin, colistin, clindamycin and trimethoprim, singly and in combination, were added to the copolymer and test pieces were made. These were then tested using an established method (SPTT) which determines degree and duration of antimicrobial activity as well as risk of emerging resistance. Test bacteria were Staphylococcus epidermidis, Staphylococcus aureus, MRSA and Escherichia coli. Mechanical properties (compressive strength and porosity) were determined using established methods.

SUMMARY

The relationship between component position, wear rate and edge loading was investigated for 115 explanted current generation Metal-on-Metal (MoM) hips. Edge wear was detected in: 63% of all hips; and 48% of those with cups positioned within Lewinnek's box.

BACKGROUND

The link between steeply inclined cups (>55 degrees) and edge loading is known for all common hip bearing couples. Edge loading is associated with high rates of wear, and has been linked to premature failure of hips.

Introduction

Articular hyaline cartilage has a unique structural composition that allows it to endure high load, distribute load to bone and enables low friction movement in joints. A novel acellular xenogenic graft is proposed as a biological cartilage replacement, for repair of osteochondral defects. Acellular porcine cartilage has been produced using repeated freeze thaw cycles and washing using hypotonic buffers and sodium dodecyl sulphate solution (SDS; Keir, 2008). DNA content of the acellular matrix was reduced by 93.3% compared to native cartilage as measured by nanodrop spectrophotometry of extracted DNA, with a corresponding reduction in glycosaminoglycan (GAG) content.

Hypothesis

It was hypothesised that penetration of decellularisation solutions into the native tissue could be improved through deformation of the cartilage under confined compression and then allowing the osteochondral pin to recover in solution, allowing removal of cellular DNA and greater retention of the GAGs.

Introduction

Iatrogenic proximal femur hoop-stress fracture is a recognised complication of uncemented hip arthroplasty. It has a reported incidence of two to three percent and increases patient morbidity. We describe a novel technology that predicts fracture in real-time by less than one minute.

Method

Four proximal femora from red deer (Cervus elaphus), similar size to human proximal femora, were prepared to accept an uncemented hip arthroplasty femoral rasp (Finsbury Orthopaedics) and then mounted in a loading machine. The femora were fresh-frozen, defrosted and kept at room temperature in 0.9% saline swabs. The rasp was forced into each femur in repeated loading cycles every 10 seconds, in steps of 100N increasing from 200N to over 2000N until fracture, in a manner to simulate surgery. One sensor was attached to the surface of the proximal femur and one to the femoral rasp. The sensor outputs were recorded, analysed and displayed on a PC using a software algorithm to show signal energy (joules) and amplitude (decibels). The proximal femur was coated with specular marking paint to permit real-time 3-D digital image correlation (DIC) analysis. DIC is an established tool in engineering fracture analysis and utilises two spatially orientated video cameras to measure surface strain and fracture. The femur was observed by the human eye and loaded in cycles until a fracture was seen. The moment of fracture was marked in the recording timeline. DIC was used to confirm fracture.

Purpose

Functional ultrasound Elastography (FUSE) of Tendo Achilles is an ultrasound technique utilising controlled, measurable movement of the foot to non-invasively evaluate TA elastic and load-deformation properties. The study purpose is to assess Achilles tendons, paratenon and bursa mechanical properties in healthy volunteers and establish an outcome tool for TA treatment.

Methods

Forty asymptomatic Achilles tendons of 20 healthy volunteers were recruited (10 men and 10 women, age range 18-55). One patient with Acute Achilles rupture scanned to evaluate the tendon gap. Each volunteer answered the Foot and Ankle Outcome Score (FAOS) and Victorian Institute Sport Assessment score (VISA-A) questionnaires. The Achilles Tendons were divided into three thirds (total 120 Proximal, middle and distal thirds). Three longitudinal images of each third were obtained using portable US scan device (Z.one, Zonare Medical System Inc., USA, 8.5 MHz). Images processing was achieved using a MatLAb software (developed by the research team) in parallel Oxford university computers. Each 1/3rd Achilles tendon under went the following scans:

Free hand US scan

B mode and elasticity images were derived from the raw ultrasound radio frequency data. The anatomical structures mechanical properties were evaluated by a quantitative score of different colours representing stiff tissue (blue) to more soft tissue (green, yellow, red).

Introduction

It is believed that wear of replacement joints vivo in is strongly dependent on input motions (kinematics) and loading. There is difficulty in accurately measuring total disc replacement (TDR) kinematics in vivo. It is therefore desirable to ascertain the sensitivity of implant wear in vitro to perturbations of the standard testing parameters. An anterior-posterior (AP) shear force input is not currently included in the present ISO and ASTM testing standards for lumbar TDRs but is known to exist in in vivo. Other joint-replacement wear tests have shown that the phasing of input motions influences the ‘cross-shear’ process of polyethylene wear. Polyethylene bearing materials do not behave linearly to axial loading changes and so the effect on wear rate is difficult to predict. The study aim was to assess the effects on wear of a ProDisc-L TDR under the following conditions: ISO 18191-1 standard inputs; an additional input AP shear; input kinematics phasing changes; axial loading changes.

Methods

A five active degree of freedom (DOF) spine simulator was used to compare the effects of varying the kinematic and loading input parameters on a ProDisc-L TDR (Synthes Spine). A four DOF standard ISO (ISO18192-1) test was followed by a five DOF test which included the AP shear force. The standard ISO test was repeated on a second simulator (of identical design) but with the phasing of the lateral bend (LB) and flexion extension (FE) motions changed to be in-phase, creating a low cross-shear motion pattern. The standard ISO test was then modified to give half the ISO standard axial loading. All tests conducted were based on the ISO18192-1 standard for lumbar implants with 15 g/l protein lubricant and modified as described. Gravimetric wear measurements were taken every million cycles (mc) in units of milligrams (mg). Six discs were tested to give statistically significant results.

Introduction

Metal-on-metal (MoM) hip resurfacing arthroplasty is a popular choice for young and active patients. However, there are concerns recently regarding soft tissue masses or pseudotumours. The appearance of these complications is thought to be related blood metal ion levels. The level of metal ions in blood is thought to be the result of MoM wear. In the present study the contribution of acetabulum orientation to stress distribution was investigated.

Methods

Four subjects with MoM resurfacings and with known blood metal ion levels underwent motion analysis followed by CT scans. The positions of the acetabular (cup) and femoral components were determined the CT data relative to local coordinate systems in the pelvis (PCS) and the femur (FCS). Transformations, calculated from the motion analysis data, between the PCS and FCS gave the position of the cup relative to the femoral component for each frame of captured motion data.

Hip reaction forces were taken from published data1. The intersection of hip reaction force with each subject's cup and the increase in inclination required to move the force to the edge of the cup was calculated for 2% intervals during the stance phase of gait. Finite element models representing each subject's cup and femoral components were created and contact stresses were determined for the native cup inclination angle. For each model, the effect of increasing the inclination of the cup, by up to 10°, in 1° increments, was determined.

INTRODUCTION

Many patients suffering from osteoarthritis (OA) take daily glucosamine (GlcN) in the hope of slowing down disease progression and ameliorating pain. However, the physiological basis of this effect is not known. We previously presented preliminary data suggesting that GlcN prevented the increase in interleukin-1beta (IL-1b) expression caused by addition of inflammatory cytokines to cultures of healthy human articular chondrocytes. Previous studies had also shown that, in OA, epigenetic DNA methylation loss at specific CpG sites in relevant promoters ‘unsilences’ the genes and that this DNA de-methylation underlies the aberrant gene expression of proteases (Arthritis Rheum 52;3110-24). Furthermore, exogenous inflammatory cytokines have the capacity to cause DNA de-methylation in the IL-1b promoter (Arthritis Rheum. 2009, 60, 3303-3313). The aims of the present study were to investigate whether GlcN not only prevents the increased IL-1b expression, but also inhibits epigenetic unsilencing by preventing the cytokine-induced loss of DNA methylation.

METHODS

Healthy chondrocytes were isolated from the articular cartilage of four femoral heads, after operations following femoral neck fracture (ethic permission was obtained). The chondrocytes were cultured for 5 weeks in four treatment groups: no treatment (control); with IL-1b and oncostatin M (IL1b+OSM); with 2.0mM GlcN; and with IL1b+OSM+GlcN. Total RNA and genomic DNA were extracted. The % DNA methylation at the CpG site at -299bp (previously identifies as the crucial CpG site) was determined after bisulphite modification with a pyrosequencer. Gene expression of IL-1B was quantified by SybrGreen-based qRT-PCR.

Introduction

Acetabular fractures are a challenging problem. It has been published that outcome is dependent upon the type of fracture, the reduction of the fracture and concomitant injuries. The end-points of poor outcome include avascular necrosis of the femoral head, osteoarthritis. However, we lack definitive statistics and so counselling patients on prognosis could be improved. In order to achieve this, more outcome studies from tertiary referral centres are required. We present the first long term follow up from a large tertiary referral centre in Ireland.

Methods

We identified all patients who were ten years following open reduction and internal fixation of an acetbular fracture in our centre. We invited all of these patients to attend the hospital for clinical and radiographic follow-up. As part of this, three scoring systems were completed for each patient; the Short-form 36 health survey (SF36), the Merle d'Aubigné score and the Short Musculoskeletal Functional Assessment (SMFA).

Introduction

Kager's fat pad (KFP) is located in Kager's triangle between the Achilles tendon (AT), the superior cortex of the calcaneus and Flexor Hallucis Longus (FHL) muscle & tendon. Although the biomechanical functions of KFP are not yet fully understood, a number of studies suggested that KFP performs important biomechanical roles including assisting in the dynamic lubrication of the AT subtendinous area, protection of AT vascular supply, and load and stress distribution within the retrocalcaneal bursa space. Similar to the knee meniscus, KFP has become under increasing investigations since strong indications were found that it serves more than just a space filler. Both KFP and the knee meniscus are anchored to their surrounding tissues via fibrous attachments, they can be found in encapsulated (or ‘air tight’) regions, lined by synovial membranes, and they both slide within their motion ranges. The protruding wedge (PW) of KFP was observed to slide in and out of the retrocalcaneal bursal space during ankle plantarflexion and dorsiflexion, respectively. In-vitro studies of KFP suggest that it reduces the load by 39%, which is similar to that of the knee meniscus (30%-70% of the load applied on the knee joint). This study investigated the in-vivo load bearing functionality of KFP.

Materials and Methods

The ankles of 5 volunteers (3 males, 2 females, Age 20-28, BMI 21-26) were scanned using a 0.2T MRI scanner at ankle plantarflexion and neutral positions. The ankles of 2 of those volunteers were later scanned using a 3T MRI scanner for higher accuracy. The areas and volumes of KFP were measured using Reconstruct¯ 3D modelling software. The hind foot of the volunteers were scanned using dynamic ultrasound to measure in-vivo real time shape changes of PW.

Introduction

The results of the original mobile bearing Oxford unicompartmental knee replacement (UKR) in the lateral compartment have been disappointing because of high dislocation rates (11%). This original implant used a flat bearing articulation on the tibial tray. To address the issue of dislocation a new implant (domed tibia with biconcave bearing to increase entrapment) was introduced with a modified surgical technique. The aim of this study was to compare the risk of dislocation between a domed and flat lateral UKR.

Methods

Separate geometric computer models of an Oxford mobile bearing lateral UKR were generated for the two types of articulation between the tibial component and the meniscal bearing: Flat-on-flat (flat) and Concave-on-convex (domed). Each type of mobile bearing was used to investigate three distinct dislocation modes observed clinically: lateral to medial dislocation, with the bearing resting on the tray wall (L-M-Wall); medial to lateral dislocation, out of the joint space (M-L); anterior to posterior dislocation, out of the joint space (A-P).

A size C tray and a medium femoral component and bearing were used in all models. The femoral component, tibial tray and bearing were first aligned in a neutral position. For each dislocation the tibial tray was restrained in all degrees of freedom. The femoral component was restrained from moving in the anterior-posterior directions and in the medial-lateral directions. The femoral component was also restrained from rotating about the anterior-posterior, medial-lateral and superior-inferior directions. This meant that the femoral component was only able to move in the superior-inferior direction. Different bearing sizes were inserted into the model and the effect that moving the femoral component medially and laterally had on the amount of distraction required to cause bearing dislocation was investigated.

INTRODUCTION

Intramedullary nail fixation has been used for successful treatment of long bone fracture such as humerus, tibia and femur. We look at the experience of our trauma unit in treating long bone fracture using the AO approved Expert femoral/tibial nail and proximal femoral nail antirotation (PFNA). We look at the union and complication rates in patients treated with AO approved nailing system for pertrochanteric, femoral and tibial shaft fracture.

METHODS

We carried out retrospective case notes review of patients that underwent femoral and tibial nailing during the period of study- October 2007 to August 2009. All patients were treated using the AO approved nailing system. We identified all trauma patients that underwent femoral and tibial nailing through the trauma register. Further information was then obtained by going through medical notes and reviewing all followed-up X-rays stored within the online radiology system.

Study Aim

Femoral components used in total knee arthroplasty (TKA) are primarily designed on the basis of kinematics and ease of fixation. This study considers the stress-strain environment in the distal femur due to different implant internal geometry variations (based on current industry standards) using finite element (FE) analyses. Both two and three dimensional models are considered for a range of physiological loading scenarios – from full extension to deep flexion. Issues associated with micro-motion at the bone-implant interface are also considered.

Materials and methods

Two (plane strain) and three dimensional finite element analyses were conducted to examine implant micro-motions and stability. The simple 2D models were used to examine the influence of anterior-posterior (AP) flange angle on implant stability. AP slopes of 3°, 7° and 11° were considered with contact between bone and implant interfaces being modeled using the standard coulomb friction model. The direction and region of loading was based on loading experienced at full extension, 90° flexion and 135° flexion. Three main model variations were created for the 3D analyses, the first model represented an intact distal femur, the second a primary implanted distal femur and the third a distal femur implanted with a posterior stabilising implant. Further each of the above 3D model sets were divided into two group, the first used a frictional interface between the bone and implant to characterise the behavior of uncemented implants post TKA and the second group assumed 100% osseointegration had already taken place and focused on examining the subsequent stress/strain environment in the femur with respect to different femoral component geometries relative the intact distal femur model.

SUMMARY

We report a prospective study of clinical data collected pre, intra and post operation to remove both cup and head components of 118 failed, current generation metal on metal (MOM) hips. Whilst component position was important, the majority were unexplained failures and of these the majority (63%) had cup inclination angles of less than 55 degrees. Poor biocompatibility of the wear debris may explain many of the failures.

BACKGROUND

Morlock et al reported a retrospective analysis of 267 MOM hips but only 34 head and cup couples (ie most were femoral neck fractures) and without data necessary to define cause of failure. The commonest cause of failure in the National Joint Registry (NJR) is unexplained.

Aim

To control the growth and function of osteoblasts on Titanium alloy surfaces produced by electrochemical patterning.

Methods

Samples of Ti6Al4V were prepared with three different finishes; no surface preparation following machining, polishing on a grinding wheel with sequential grit papers up to 4000 to achieve a mirror finish and treatment in a flat electrochemical cell with a 3M sulphuric acid in methanol using 9V supplied over 60 seconds to produce a surface with defined nano/microscale roughness. Glass coverslips were used as control surfaces. Surfaces were seeded with primary rat calvarial osteoblasts and incubated in Dulbecco's Modified Eagle Medium with 10% (v/v) sera for 24 hours before fixing and performing immunofluorescence staining with anti-vinculin antibody. Photomicrographs of the surfaces were analysed with Image J and analySIS FIVE programs. Results for cell number, cell area, focal adhesion area and polarity (lack of roundness) were analysed (using the Mann Whitney test) for ANOVA using SPSS.

Introduction

Mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. We have previously demonstrated that the infrapatellar synovial fat pad is a rich source of mesenchymal stem cells and these cells are able to undergo chondrogenic differentiation. Although synovial fat pad derived mesenchymal stem cells may represent a heterogenous population, clonal populations derived from the synovial fat pad have not previously been studied.

Materials and Methods

Mesenchymal stem cells were isolated from the infrapatellar synovial fat pad of a patient undergoing total knee arthroplasty and expanded in culture. Six clonal populations were also isolated before initial plating using limiting dilution and expanded. The cells from the mixed parent population and the derived clonal populations were characterised for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium for 14 days. Gene expression analyses; glycosoaminoglycan and DNA assays; and immunohistochemical staining were determined to assess chondrogenic responses.

AIM

When a hip is replaced using a posterior surgical approach, some of the external rotator muscles are divided. The aim of this study was to assess if this surgery has a long term affect on hip rotation during activities of daily living.

METHODS

An electromagnetic tracking system was used to assess hip movements during the following activities:-

Activity 1. Picking an object of the floor in a straight leg stance.

Activity 2. Picking an object of the floor when knees are flexed.

Activity 3. Sitting on a chair.

Activity 4. Putting on socks, seated, with the trunk flexed forward.

Activity 5. Putting on socks, seated, with the legs crossed.

Activity 6. Climbing stairs.

Measurements were taken from 10 subjects with bilaterally normal hips, 10 patients with a large head hip replacement, 10 patients with a resurfacing head and 10 patients with a small head hip replacement. All the hip replacement patients were at least 6 months post-op, with an asymptomatic contra-lateral native hip for comparison. Sensors were attached over the iliac crest and the mid-shaft of the lateral thigh. Data was collected as each activity was repeated 3 times. The tracker recorded hip rotation at 10 hertz, with an accuracy of 0.15 degree.

ABSTRACT

The friction and lubrication behaviour of four Biomet ReCap components with a nominal diameter of 52 mm and diametral clearance ranging from 167-178 μm were investigated using a friction hip simulator. Friction testing was carried out using pure bovine serum and aqueous solutions of bovine serum (BS), with and without carboxymethyl cellulose (CMC), adjusted to a range of viscosities (0.001-0.236 Pas). The Stribeck analyses suggested mixed lubrication as the dominant mode with the lowest friction factor of 0.07 at a viscosity of 0.04 Pas.

INTRODUCTION

The femoral resurfacing systems provide an alternative to hemi and total hip arthroplasty and offer several unique advantages including large resurfacing heads (>35–60 mm diameter) allowing increased range of motion (and stability) over the traditional 28 mm artificial hip joints, with excellent tolerances and surface finish leading to a reduction in wear, as well as preserving primary bone with the femoral canal remaining untouched. This work has investigated the friction and lubrication behaviour of four 52 mm metal-on-metal Biomet ReCap components with a clearance of 167-178 μm using serum-based lubricants.

Objective

To determine the reliability, reproducibility, variability and validity of the Osteoarthritis Research Society International (OARSI) Osteoarthritis Cartilage Histopathology (OACH) system and Mankin Histopathology – Histochemical Grading System (HHGS) when applied to the characterisation of the osteoarthritic human knee.

Method

Kellgren-Lawrence and Line Drawing Atlas (LDA) radiology scores clinically graded the knees of ten patients undergoing total knee arthroplasty due to osteoarthritis. The tibial plateaux were scored using the Modified Collins (MC) and Société Française d'Arthroscopie (SFA). Three observers, twice scored, using both the OACH and HHGS systems across a single complete medial and lateral tibial plateau transect taken to include the region with the most severe OA lesion. Intra and inter-observer reliability, reproducibility, variability and validity were quantified, and the correlation between the two histopathology scoring systems was calculated.

Objective of the study

To determine if the location and pattern of knee pain as described by the patients using the knee pain map was comparable with the intra articular pathology found on arthroscopy as well as to facilitate diagnosis based on pain.

Methods

There were Sixty consecutive patients with acute and chronic knee pain participating in the study and they subsequently underwent arthroscopy of the knee joint as therapeutic or diagnostic procedure in day surgery.

Those patients with extra articular pathologies, referred pain hip, back and foot were excluded from the study.

All the participants were consented for the study; subjective data was recorded on the standardised knee pain map that included visual analogue pain scale preoperatively on the day of admission for arthroscopy.

The findings of the arthroscopy including EUA were recorded on the on standard arthroscopy forms used in our department by the operating surgeon.

Introduction

The use of the dynamic hip screw is common practice for the fixation of intertrochanteric fractures of the femur. The success of this procedure requires accurate guide wire placement. This can prove difficult at times and can result in repeated attempts leading to longer operating time, multiple tracks and more importantly greater radiation exposure to both patient and operating staff. We hypothesised that rather than using the standard anterior-posterior projected image (Figure 1) of a proximal femur, rotating the intensifier image (Figure 2) so that the guide wire appears to pass vertically makes it easier to visualise the projected direction of the guide wire.

Methods

Fifty Specialist Registrars, thirty participating in the London hip meeting 2009, ten from Oxford and ten from Northern deanery orthopaedic rotations were involved in the study. They were presented with standard AP and rotated images of the femoral neck on paper using 135 degree template to replicate the DHS guide.

The participants were asked to mark the entry point on the intertrochanteric area of femur on the image where they would have placed the guide wire. They did this on both standard AP and rotated images aiming for the centre of the head of the femur. Fig. 1 Standard AP image Fig. 2 Rotated image

ABSTRACT

The viscosity and shear stress versus shear rate relationship for pure bovine serum (BS) and its aqueous solutions with and without carboxymethyl cellulose (CMC) were investigated. BS and diluted BS without CMC showed pseudoplastic flow curves up to a critical shear rate of ∼100 s-1 above which a Newtonian flow with significant rise in shear stress was observed. The viscosity flow curve for the diluted BS+5g CMC showed only shear thinning up to a shear rate of 3000 s-1 whereas diluted BS+1g or +2g CMC showed similar flow curves to pure BS. The shear rate application modified the flow behaviour of BS from a pseudoplastic to a Newtonian flow depending on its purity and CMC content. Friction factor was dependent on viscosity and clearance with mixed lubrication as the dominant mode within the viscosity range 0.001-0.044 Pas.

INTRODUCTION

Pure BS and diluted BS are used as in vitro lubricants for tribological studies. Boundary, mixed and fluid film lubrication are the mechanisms involved in the lubrication of both natural and artificial joints. Clearance and lubricant viscosity will influence the nature of contact between the articulating surfaces. The objectives of this work were to study the flow properties of serum-based lubricants with different viscosities and the correlation between the rheological properties and frictional (and lubrication) behaviour of large diameter Biomet ReCaps with various clearances.

Objective

To determine the use of oral anti-inflammatory drugs use in the year before and the two years after primary total hip (THR) or knee (TKR) replacement, and to assess whether this varied according to the Body mass Index (BMI).

Design

Population based retrospective case control study.

Background, Context and Motivation

“Increases in reconstructive orthopaedic surgery, resulting from advances in surgical practice and the ageing population, have lead to a demand for bone graft that far exceeds supply.”…Traditional bone grafting methods have been linked with a number of negative issues including increased morbidity due to secondary operation site and action as a vector for spread of disease. (Hing 2004). A solution to these insufficiencies would be the creation of a synthetic osteoinductive bone graft material. This would vastly improve bone graft surgery success rates and expedite post-op recovery times. The aim of this study was to classify then explore the dissolution rates of three experimental hydroxyapatite/silicate apatite synthetic bonegrafts in physiological solutions, (phosphate buffered saline, (PBS) +/− serum proteins, (PBS +FCS). The overall objective being to identify whether there is an explainable significant difference in ion exchange that could be behind the osteoinductive phenomena.

Methods Used

Classification of the apatite samples, (HA, SA1 and SA2), was conducted via X-Ray diffraction, FTIR-PAS Spectroscopy and SEM with EDS analysis. A dissolution experiment of the experimental apatites was conducted in PBS and PBS + FCS solutions, over time periods of 1, 2 and 4 hours, and at 1, 2, 4 and 8 days, with repeat measures.

Introduction and aims

Biomechanical testing has been a cornerstone of the development of surgical implants for fracture stabilisation. To date most fracture surgery implant design and testing has been dominated by the use of standard bench top biomechanical testing. Although such methods have been used to successfully reproduce certain clinical observations, there are very clear limitations. More recently however, computerised engineering technology using finite element analysis (FEA) has been used to research orthopaedic biomechanical testing. This study aims to use FEA technology to further understand proximal femoral fractures, simulating falls, recreating fracture patterns and analyse fracture fixation devices for such fractures.

Study design and results

In a multi-disciplinary collaboration, novel clinically relevant models were developed at Swansea University using advanced computational engineering. In-house software (developed initially for commercial aerospace engineering), allowed accurate finite element analysis (FEA) models of the whole femur to be created, including the internal architecture of the bone, by means of linear interpolation of Greyscale images from multiaxial CT scans. This allowed for modeling the changing trabecular structure & bone mineral density in progressive osteoporosis. Falls from standing were modeled in a variety of directions, (with & without muscle action) using analysis programs which resulted in fractures consistent with those seen in clinical practice.

By meshing implants into these models and repeating the mechanism of injury in simulation, periprosthetic fractures have been successfully recreated.

Introduction

Primary Total Elbow Replacement (TER) is gaining popularity as a primary treatment option for osteoporotic fractures of the elbow, particularly in patients with low demand. The aim of this study was to assess the clinical and functional efficacy of TER as a primary treatment for comminuted distal humerus fractures in the elderly.

Methods

We retrospectively reviewed twenty-three patients (22 females and 1 male) who were treated with primary total elbow replacement for complex, intra-articular fractures of the distal humerus in the elderly between March 2000 and January 2010. The average age of the patients was seventy-five years (ranging from 66 to 94 years). Postoperative elbow function was assessed using the Mayo Elbow Performance Score. The radiological assessment was performed using antero-posterior and lateral radiographs done at follow-up appointments.

Half-pin fixation

Increasing the number of half-pins from two to three produced an approximate 80% reduction of yielded bone volume in all age groups. The volume of yielded bone increased with ageing, approximately three times greater in old-aged bone than in young bone. In the young and middle-aged cases yielded bone never penetrated the full cortex. Contrastingly, the full cortex was yielded in the old-aged bone fragments for both two- and three-pin fixation. In all cases the volume of yielded bone was greater at the pin(s) nearest to the fracture gap. The use of titanium pins increased the volume of yielded bone around half-pins by approximately 1.7 times. These results suggest bone competence, number of half-pins, location of half-pins and half-pin material all significantly influence implant loosening.

Illizarov wire fixation

Increasing the number of Illizarov wires reduced the volume of yielded bone by approximately 60% in all age groups. The volume of yielded bone increased with ageing by a factor of approximately 2.0 times from young to old bone. Bone yielding never progressed through the entire cortex; it reached a maximum of 70% of the cortical thickness in two-wire fixation of the old-aged bone fragment. This is a possible reason for the lower rate of loosening in Illizarov wire fixation as compared to half-pin fixation. Increasing wire tension reduced the volume of yielded bone. These results suggest that bone competence, number of wires, wire tension and wire arrangement significantly influence loosening.

Study aim

There is an ever increasing demand for quality clinical trials in surgery. Surgeons' co-operation and enthusiasm to participate are important, if not crucial in success of such studies, especially if they are multi-centred. Clinician's individual uncertainty (equipoise) about a case has been often cited as an ethical basis for inviting a patient to take part in a clinical trial. This study aims to establish current attitudes of surgeons participating in a national multi-centred randomised controlled trial and explores an on line tool for instant assessment of collective uncertainty (equipoise) for individual clinical cases eligible for a trial.

Study design

Surgeons taking part in the UK Heel Fracture Trial were invited to take part. If agreed, they were asked to evaluate treatment prognosis for eligible for the trial anonymised cases of calcaneal fractures online by means of specially designed system. The cases were published on a password protected website on ad-hoc basis during the three years course of the trial. Their responses were submitted instantly on line.

INTRODUCTION

Warfarin remains the treatment of choice for the majority of patients with venous thromboembolism, atrial fibrillation and valvular heart disease or valve replacement unless contraindicated. Poor management of patients on warfarin often leads to delay in surgery, life threatening bleeding during or after operation and unnecessary delay in discharge from hospitals in United Kingdom.

METHODS

We carried out a prospective study on patients who were on warfarin and underwent elective and emergency orthopaedic procedures during period of study- August 2007 to April 2008. All patients included in the study were identified from admission notes during period of study. All data regarding indications for warfarin, pre and post procedures INR, elective or emergency orthopaedic procedures and complications were collected using a standard proforma.

Background

Fractured neck of femurs cause substantial morbidity and mortality in elderly patients and represent a huge financial burden to the NHS. Hip fracture patients are generally malnourished on admission, often having poor nutritional inpatient intake, hindering recovery and increasing chances of “unfavourable outcome.” Nutritional care is included in intercollegiate guidelines for management of fractured neck of femur patients, but is nutrition a management priority in clinical practice?

Study Aim

To evaluate protein and energy intake of acute fractured neck of femur patients depending on admission MMSE, and compare these to department of health targets.

Background

Recent articles in the medical press highlight the potential dangers of Cauda Equina Syndrome (CES). CES has the highest rates of litigation due to its long-term neurological impairment, which can lead to devastating outcome on patients. The aim of this study was to assess health care professionals knowledge with regards to the urinary symptoms of CES and the timeframe in which treatment should be offered.

Objectives

To assess health care professionals knowledge with regards to urinary symptoms of CES and when treatment should be offered.

Introduction

It has been suggested that the transition phases of implementing daylight saving time (DST) may impact on serious or fatal injuries sustained as the result of road traffic collision (RTC). The aim of this study is to explore the effects of transitions into and out of daylight saving time on the incidence of such injuries.

Method

This is a retrospective comparative observational study of 11-year of data submitted prospectively to the Trauma Audit Research Network (TARN) between 1996 and 2006. Data for 4 weeks before and after time transition in spring and autumn of each year was collected. The time periods selected reflect those hours with maximum light level changes due to time alterations (2-hour around sunrise and 4-hour around sunset). Travellers outside those hours are unlikely to be affected by the changes.

Background

The treatment of olecranon fractures frequently involves the use of tension band fixation. Although associated with high union rates, this method has a high incidence of morbidity associated with soft tissue compromise and limitation of range of movement requiring frequent re-operation for removal of metal.

Objectives

We describe the use of a simple jig to ensure intramedullary placement of longitudinal K-wires and compare the accuracy of placement of wires using this device with the traditional free hand method.

Aim

To identify differences in hip muscle strength, knee valgus during a single leg squat (SLS),and function between subjects with Greater Trochanter Pain Syndrome (GTPS) and healthy(H) subjects. To determine associations between pain, function, hip strength and SLS in GPTS subjects. Study Design: Observational study of 14 (3 male 11 female) PFP patients (mean symptom duration 17 months), matched for age height and weight with 14 healthy (H) subjects, All subjects fulfilled specific inclusion and exclusion criteria. Appropriate Ethical approval was obtained. Measures for both groups were Knee valgus angle during SLS using 2D motion capture and SiliconCoach software for measurement of knee valgus angles, hip abduction, internal and external rotation muscle strength using hand held dynamometry, visual analogue scale for pain. Lower Extremity Functional Scale (LEFS). All measures were taken on the affected leg for GPTS subjects and matched for the equivalent leg in healthy group. Strength was reported as a percentage of body weight. SiliconCoach was reliable for intra-rater reliability of knee valgus angle (ICC.996).

Results

There were no significant differences in age, height and weight (p=.85,.57,.51 respectively). Significant differences existed in hip abduction strength p=.005(GPTS13.72 (7.65), H21.49 (5.55)) and LEFS p=0.001(GPTS 57.28(16.55), H76.92(4.44)). There were no significant differences in internal and external rotation and knee valgus angles p=.509, p=.505, p=.159 respectively. There was a negative correlation between pain and function r=.879) p=0.001) and a moderate positive correlation between function and hip abduction strength r=.428 (p=.127).

This preliminary study shows that patients with GPTS have reduced strength in hip abductor musculature when compared to healthy subjects. This may be due to pain inhibition; however the true causes of pain need to be determined. Pain and to a lesser extent hip abductor strength appears to have an effect on function in GPTS patients. In summary the results indicate that hip abductor muscle strengthening and management strategies to reduce pain should be included in the rehabilitation programmes of patients with GPTS. Further research with larger numbers of subjects should be developed to investigate this subject.

Aim

To determine differences in knee valgus angles produced during a single leg squat and hip muscle strength between healthy subjects and patients with patellofemoral pain (PFP). To determine correlations between variables of hip muscle strength, knee valgus angle and pain. Study design: Observational study of 20 (8 male 12 female) healthy (H) subjects, matched for age height and weight with 20 (8 male 12 female) PFP patients (mean symptom duration 46.75 weeks). All subjects fulfilled specific inclusion and exclusion criteria. Appropriate Ethical approval was obtained. Measures for both groups were Knee valgus angle during a single leg squat using 2D motion capture and SiliconCoach software for measurement of knee valgus angles, hip abduction, internal and external rotation muscle strength using hand held dynamometry, visual analogue scale for pain. Strength was reported as a percentage of body weight. All measures were taken on the affected leg for PFP subjects and matched for the equivalent leg in healthy group. SiliconCoach was determined to be reliable for intra-rater reliability of knee valgus angle (ICC.996).

Results

There were no significant differences in age, height and weight (p=.59,.51,.26 respectively). Significant differences existed in hip abduction strength p=.001(PFP 19.93(9.2), H 32.22(8.26)), Hip internal rotation p=0.001 (PFP 12.94(4.35), H 19.53(6.36)), Hip external rotation p=0.001(PFP 10.00(3.07), H 16.26 (4.62)), Knee Valgus Angles p=0.001(PFP 5.31(2.59), H 2.29 (2.35)). No correlations existed between any of the variables including pain.

This preliminary study shows that patients with PFP have larger knee valgus angles when doing a single leg squat and significantly weaker hip muscle strength when compared to healthy subjects. The reason for larger knee angles during single leg squat could be hypothesised as being due to weak hip abductor muscles not sufficiently controlling the alignment of the femur. However no correlations were found for these measures, nor were they found for any of the other variables including pain level. In summary the results indicate that hip musculature strengthening of the rotators and abductors and measures to reduce knee valgus angle should be included in the rehabilitation programme of patients with PFP. Further research with larger numbers of subjects should be developed to investigate this subject.

INTRODUCTION

There is increasing worldwide interest in the assessment of wear in explanted hip components. This is due is part to high profile failures of orthopaedic components in the US, whilst in the UK hip resurfacings have been experiencing a higher than expected failure rate. The reasons for these failures are not well understood, with data from the NJR suggesting the 43% of MoM resurfacing failures are unexplained.

Wear analysis is a vital tool in determining failure mechanisms and ultimately improving the longevity of joint replacements through improved design and manufacturing control. There are currently no relevant measurement standards for the evaluation of retrieved orthopaedic components. This paper will assess two of the most commonly used techniques namely roundness measurement and co-ordinate measurement. The advantages and disadvantages of both techniques are considered in this paper.

ROUNDNESS MACHINE

The Talyrond 365 is a stylus based roundness machine. The component is located on a rotating table and the stylus measures the deviation from a perfect circle as the component is slowly rotated. The Talyrond measures a single profile to an accuracy of 30 nm and up to 72,000 data points per revolution. The air spindle has a radial accuracy of <0.02 μm and the Talymin gauge a minimum resolution of 12 nm. Individual roundness profiles can be stitched together to build up 3D cylinder maps, allowing 3D pictures of sections of explanted hip components to be generated.

Introduction

Isolated midcarpal motion during radioulnar deviation could be approximated to be a rotation in a plane of a radiodorsal/ulnopalmar rotation of the wrist, which may coincide with a motion plane of one of the most essential human wrist motions, known as the dart-throwing motion. This has been studied before in normal volunteers using Magnetic Resonance Imaging to study in vivo kinematics of the midcarpal joint in the wrists of normal volunteers. We present the early results of use of biaxial flexible electrogoniometer to study the range of motion in patients with four-corner fusion.

Methods

Ten patients with four-corner fusion for SLAC/SNAC wrist were assessed to study flexion-extension, radial-ulnar deviation, and circumduction motions using flexible electrogoniometers. Opposite unaffected wrist was studied to provide normal data. Angle-angle curves (Lissajous's figures) were generated to study the area under the curve and comparison with the normal wrists and also to study the deviation from the neutral axis. Five normal volunteers were also studied to calculate the area under the curve and the axis of deviation during circumduction of the wrist.