National guidelines encourage the use of total hip arthroplasty (THA) to treat intracapsular neck of femur fractures. There have been no population based studies appraising the surgical outcomes for this indication across an entire population. This study aims to calculate the complication rates for THA when performed for a fractured neck of femur and compare them to THA performed for primary osteoarthritis in the same population.

The Scottish Arthroplasty Project identified all THAs performed in Scotland for neck of femur fracture and osteoarthritis between 1st of January 2009 and 31st December 2014. Dislocation, periprosthetic infection and revision rates at 1 year were calculated.

The rate of dislocation, periprosthetic infection and revision at 1 year were all significantly increased among the fracture neck of femur cohort. In total 44046 THAs were performed, 38316 for OA and 2715 for a neck of femur fracture. 2.1% of patients (n=57) who underwent a THA for a neck of femur fracture suffered a dislocation in the 1st year postoperatively, compared to 0.9% (n=337) when the THA was performed for osteoarthritis. Relative Risk of dislocation: 2.4 (95% C.I. 1.8077–3.1252, p value <0.0001). Relative Risk of infection: 1.5 (95% C.I. 1.0496–2.0200, p value 0.0245) Relative Risk of revision: 1.5 (95% C.I. 1.0308–2.1268, p value 0.0336).

This is the first time a dislocation rate for THA performed for a neck of femur fracture has been calculated for an entire population. As the number of THAs for neck of femur fracture increases this dislocation rate will have clinical implications.

The burden of osteoporosis (OP), and its accompanied low energy fractures, is ever increasing. Targeted therapies are under development to stem the tide of the disease, with microRNAs identified as biomarkers and potential targets. Assessing the functional capacity of bone marrow mesenchymal stromal cells (BMSC) from patients with low energy neck of femur fractures (NOF) will identify the expected outcomes to be achieved from new, targeted osteogenic therapies.

Two patient groups were assessed; low energy NOF and osteoarthritic. Bone marrow aspirates were taken at time of arthroplasty surgery. The adherent fraction was cultured and assessed by flow cytometry, microRNA expression and differentiation functionality.

Both patient groups demonstrated characteristic extracellular markers of BMSCs. 3 key markers were significantly reduced in their expression in the NOF group (CD 90, 13, 166 P=0.0286). Reduced differentiation capacity was observed in the NOF group when cultured in osteogenic and adipogenic culture medium. 105 microRNAs were seen to be significantly dysregulated, with microRNAs known to be crucial to osteogenesis and disease process such as osteoporosis abnormally expressed.

This data demonstrates the impaired functional capacity of BMSCs and their abnormal microRNA expression in patients who suffer a low energy NOF. Future targeted therapies for OP must address this to maximise their restorative effect on diseased bone. The important role microRNAs can play as biomarkers and target sites has been further reinforced.

Since the introduction of national guidelines in 2009 encouraging the use of total hip arthroplasty (THA) to treat intracapsular neck of femur fractures there has been no population-based studies into the surgical outcomes for this indication. This study aims to calculate the complication rates for THA when performed for a fractured neck of femur and compare them to THA performed for primary osteoarthritis in the same population.

The Scottish Arthroplasty Project was used to identify all THAs performed in Scotland for neck of femur fracture and osteoarthritis between 1st of January 2009 and 31st December 2014. Dislocation, infection and revision rates at 1 year were calculated.

The rate of dislocation, infection and revision at 1 year were all significantly increased among the fracture neck of femur cohort. In total 44046 THAs were performed, 38316 for OA and 2715 for a neck of femur fracture. 2.1% of patients (n=57) who underwent a THA for a neck of femur fracture suffered a dislocation in the 1st year postoperatively, compared to 0.9% (n=337) when the THA was performed for osteoarthritis. Relative Risk of dislocation: 2.3870 (95% C.I. 1.8077–3.1252, p value <0.0001). Relative Risk of infection: 1.4561 (95% C.I. 1.0496–2.0200, p value 0.0245) Relative Risk of revision: 1.4807 (95% C.I. 1.0308–2.1268, p value 0.0336).

This is the first time a dislocation rate for THA performed for a neck of femur fracture has been calculated for an entire population. As the number of THAs for neck of femur fracture increases this dislocation rate will have clinical implications.

We have developed precision-engineered strontium eluting nanopatterned surfaces. Nanotopography has been shown to increase osteoblast differentiation, and strontium is an element similar to calcium, which has been proven to increase new bone formation and mineralization. This combination has great potential merit in fusion surgery and arthroplasty, as well as potential to reduce osteoporosis. However, osteoclast mediated osteolysis is responsible for the aseptic failure of implanted biomaterials, and there is a paucity of literature regarding osteoclast response to nanoscale surfaces. Furthermore, imbalance in osteoclast/osteoblast resorption is responsible for osteoporosis, a major healthcare burden. We aimed to assess the affect of strontium elution nanopatterned surfaces on osteoblast and osteoclast differentiation.

We developed a novel human osteoblast/osteoclast co-culture system without extraneous supplementation to closely represent the in vivo environment. We assessed the surfaces using electron microscopy (SEM), protein expression using immunofluorescence and histochemical staining and gene expression using polymerase chain reaction (PCR).

In complex co-culture significantly increased osteoblast differentiation and bone formation was noted on the strontium eluting, nanopatterned and nanopatterned strontium eluting surfaces, suggesting improved osteointegration. There was a reduction in macrophage attachment on these surfaces as well, suggesting specific anti-osteoclastogenic properties of this surface.

Our results show that osteoblast and osteoclast differentiation can be controlled through use of nanopatterned and strontium eluting surface features, with significant bone formation seen on these uniquely designed surfaces.

Nanotopographical cues on Ti surfaces have been shown to elicit different cell responses such as differentiation and selective growth. Bone remodelling is a continuous process requiring specific cues for optimal bone growth and implant fixation. In addition, the prevention of biofilm formation on surgical implants is a major challenge. We have identified nanopatterns on Ti surfaces that would be optimal for both bone remodelling and for reducing risk of bacterial infection. We used primary human osteoblast/osteoclast co-cultures and seeded them on flat Ti and three Ti nanosurfaces with increasing degrees of roughness, manufactured using anodisation under alkaline conditions (for 2, 2.5 and 3 hours). Cell growth and behaviour was assessed by scanning electron microscopy (SEM), immunofluorescence microscopy, histochemistry and quantitative RT-PCR methods. Bacterial growth on the nanowire surfaces was also assessed by confocal microscopy and SEM. From the three surfaces tested, the 2 h nanowire surface supported osteoblast and, to a lesser extent, osteoclast growth and differentiation. Bacterial viability was significantly reduced on the 2h surface. Hence the 2 h surface provided optimal bone remodelling conditions while reducing infection risk, making it a favourable candidate for future implant surfaces. This work was funded by EPSRC grant EP/K034898/1.

Osteoporosis is an international health and financial burden of ever increasing proportions. Current treatments limit the rate of bone resorption and reduce fracture risk, however they are often associated with significant and debilitating side effects. The most commonly used therapies also do not stimulate osteoblast activity. Much current research focus is aimed at the metabolic and epigenetic pathways involved in osteoporosis. MicroRNAs have been shown to play an important role in bone homeostasis and pathophysiological conditions of the musculoskeletal system. Upregulation of specific microRNAs has been identified in-vivo in osteoporotic patients. It is hypothesized that modulation of specific mircoRNA expression may have a key role in future targeted therapies of musculoskeletal diseases. The assessment and analysis of their potential therapeutic use in Osteoporosis is of great importance, due to the burden of the disease.

We have developed a 3D osteoporotic model from human bone marrow, without the use of scaffold. Magnetic nanoparticles are utilised to form spheroids, which provides a closer representation of the in-vivo environment than monolayer culture. This model will provide the basis for analysing future microRNA experiments to assess the potential upregulation of osteoblastogenesis without cessation of osteoclast activity.

The results of initial monolayer and spheroid experiments will be presented. Optimisation of the osteoporotic bone marrow culture conditions, involving response to differentiation medias, analysis of adipose and bone markers and cell migration in spheroid culture will be displayed. Quantitative and qualitative results, including fluorescence microscopy and in cell western, assessing the monolayer and spheroid cultures will be presented. The development of a pseudo osteoporosis model from healthy bone marrow will also be discussed. This model will form a basis of future work on miRNA targeting.

Introduction

Cement in cement revision with preservation of the original cement mantle has become an attractive and commonly practised technique in revision hip surgery. Since introducing this technique to our unit we have used two types of polished tapered stem. We report the clinical and radiological outcomes for cement in cement femoral revisions performed using these prostheses.

Two major challenges in arthroplasty are obesity and antibiotic resistance. This study was performed to characterise the organisms responsible for deep infection following total hip arthroplasty and to determine if obesity affected the microbiology profile.

A retrospective analysis of the national surgical site infection register was made to obtain data regarding deep infection following 10948 primary total hip arthroplasty (THA) from 1998–2013, with a minimum of 2 year follow-up.

Of all the primary THAs performed, there were 108 deep infections (56 patients had a BMI >30 (obese) and 52 patients <30). There were no significant differences between cardio-respiratory disease, smoking and alcohol status, and diabetes between the 2 groups. Over the last 15 years, staphylococcus aureus continues to be the most frequently isolated organism. Infection with multiple organisms was found exclusively in obese patients. Furthermore, in obese patients, there was a linear increase with methicillin resistant staphylococcus aureus (MRSA) infections and streptococcus viridans.

On this basis, we recommend careful selection of antibiotic therapy in obese patients, rather than empirical therapy, which can be especially important if there is no growth in an infected THA. In addition, a preoperative discussion regarding dental prophylaxis against streptococcus viridans may be warranted.

Successful treatment of periprosthetic joint infection involves surgical intervention and identification of infecting organisms to enable targeted antibiotic therapy. Current guidelines recommend intra-operative culture sampling to include at least 4 tissue samples and for each sample to be taken with a separate instrument.

We aimed to review current revision arthroplasty practice for Greater Glasgow, specifically comparing intra-operative sampling technique for infected revision cases with these guidelines.

We reviewed the clinical notes of all patients undergoing lower limb revision arthroplasty procedures in Greater Glasgow Hospitals (WIG, GRI, SGH) from July 2013 to August 2014. Demographics of all cases were collected. For revision procedures performed for infection we recorded details of intraoperative samples taken (number, type and sampling technique) and time for samples to reach the laboratory. Results of microbiology cultures were reviewed.

Two hundred and fifty five revision arthroplasty procedures (152 hips, 103 knees) were performed in the 12 month study period. Of these 57 (22%) were infected cases (28 hips, 29 knees). These cases were treated by 14 arthroplasty surgeons with a median number of 3 infected cases managed per surgeon (range 1–11). 58% of cases had the recommended number of tissue samples taken. The median number of microbiology samples collected was 4 (range 1–14). Most procedures (91%) had no documentation of whether separate instruments were used for sampling. Number of tissue samples taken (≥4, p=0.01), time to lab (<24 hours, p=0.03) were significantly associated with positive culture results.

In Greater Glasgow, a large number of surgeons manage infected arthroplasty cases with variability in intra-operative sampling techniques. Sample collection adheres to guideline recommendations in 58% cases. Adhering to guideline standards increases the likelihood of positive tissue cultures. Implementation of a standardised approach to intra-operative sampling for infected cases may improve patient management.

Poly-ether-ether-ketone (PEEK) is a biomaterial commonly used for spinal implants and screws. It is often desirable for orthopaedic implants to osseointegrate, but as PEEK is biologically inert this will not occur. The aim of this project was to determine if injection mould nanopatterning can be used to create a make PEEK bioactive and stimulate osteogenesis in vitro.

PEEK substrates were fabricated by injection mould nanopatterning to produce near-square (NSQ) nanopatterned PEEK and planar (FLAT) PEEK samples. Atomic force microscopy (AFM) and scanning electron microscopy were used to characterize the surface topography. Human bone marrow stromal cells (hBMSCs) were isolated from patients undergoing primary hip replacement operations and seeded onto the PEEK substrates. After 6 weeks the cells were stained using alizarin red S (ARS) stain (to detect calcium) and the von Kossa technique (to detect phosphate) and analyzed using CellProfiler image analysis software to determine: surface coverage; cell number; and expression of either calcium (ARS stain) or phosphate (von Kossa technique).

ARS stain showed calcium expression (quantified relative to the number of cells) was increased on NSQ PEEK compared to FLAT PEEK (not statistically significant) and the surface coverage was similar. Von Kossa staining revealed more surface coverage on FLAT PEEK (69.1% cf. 31.9%), cell number was increased on FLAT PEEK (9803 ± 4066 cf. 4068 ± 1884) and phosphate expression relative to cell number was also increased (seven-fold) on NSQ PEEK (P < 0.05) compared to FLAT PEEK.

Although hBMSCs may adhere to NSQ PEEK in smaller numbers, the cells expressed a relatively larger amount of calcium and phosphate. This indicates that the cells adopted a more osteoblastic phenotype and that nanopatterning PEEK induces hBMSC differentiation and stimulates osteogenesis. Injection mould nanopatterning therefore has the potential to improve osseointegration of PEEK implants in vivo.

In biomaterial engineering the surface of an implant can influence cell differentiation, adhesion and affinity towards the implant. Increased bone marrow derived mesenchymal stromal cell (BMSC) differentiation towards bone forming osteoblasts, on contact with an implant, can improve osteointegration. The process of micropatterning has been shown to improve osteointegration in polymers, but there are few reports surrounding ceramics.

The purpose of this study was to establish a co-culture of BMSCs with osteoclast progenitor cells and to observe the response to micropatterned zirconia toughened alumina (ZTA) ceramics with 30 µm diameter pits. The aim was to establish if the pits were specifically bioactive towards osteogenesis or were generally bioactive and would also stimulate osteoclastogenesis that could potentially lead to osteolysis.

We demonstrate specific bioactivity of micropits towards osteogenesis with more nodule formation and less osteoclastogenesis. This may have a role when designing ceramic orthopaedic implants.

When performing total hip replacements in patients with hip dysplasia, acetabular augmentation may be required to prevent early component failure. Preoperative radiographic templating may help estimate acetabularcomponent coverage but has not previously been shown to predict the need for augmentation.

We developed a simple method to estimate the percentage of acetabular component coverage from pre-operative radiographs (True: False cup ratio). We aimed to evaluate whether this couldpredict the need foracetabular augmentation at primary total hip replacement for patients with dysplastic hips.

We reviewed all patients with hip dysplasia who underwent a primary total hip replacement from 2005–2012. Classification of hip dysplasia (Crowe), centre edge angle (CEA), Sharp and Tonnis angles were determined on pre-operative radiographs for each patient. Templating was performed on anteroposteriorand lateral view hip radiographs to determine the likely percentage of acetabular component coverage using the True: False cup ratio. Patients requiring acetabular augmentation at time of primary total hip arthroplasty were noted.

128 cases were reviewed, 31 (24%) required acetabularaugmentation. Comparison between augmented and non-augmented cases revealed no difference in the mean CEA (p = 0.19), Sharp angles (p = 0.76) or Tonnis angles (p = 0.32). A lower True Cup: False Cup ratio was observed in the augmented groupcompared to the non-augmented group(median = 0.68 vs 0.88, p < 0.01).

Preoperative templating can help predict which dysplastic hips are likely to require acetabular augmentation at primary total hip replacement.

Background

Aseptic loosening remains the primary reason for failure of orthopaedic implants. Therefore a prime focus of Orthopaedic research is to improve osteointegration and outcomes of joint replacements. The topography of a material surface has been shown to alter cell adhesion, proliferation and growth. The use of nanotopography to promote cell adhesion and bone formation is hoped to improve osteointegration and outcomes of implants. We have previously shown that 15nm high features are bioactive. The arrangement of nanofeatures has been shown to be of importance and block-copolymer separation allows nanopillars to be anodised into the titania layer, providing a compromise of control of order and height of nanopillars. Osteoblast/osteoclast stem cell co-cultures are believed to give the most accurate representation of the in vivo environment, allowing assessment of bone remodelling related to biomaterials.

Nanoscale topography increases the bioactivity of a material and stimulates specific responses (third generation biomaterial properties) at the molecular level upon first generation (bioinert) or second generation (bioresorbable or bioactive) biomaterials.

We developed a technique (based upon the effects of nanoscale topography) that facilitated the in vitro expansion of bone graft for subsequent implantation and investigated the optimal conditions for growing new mineralised bone in vitro.

Two topographies (nanopits and nanoislands) were embossed into the bioresorbable polymer Polycaprolactone (PCL). Three dimensional cell culture was performed using double-sided embossing of substrates, seeding of both sides, and vertical positioning of substrates. The effect of Hydroxyapatite, and chemical stimulation were also examined.

Human bone marrow was harvested from hip arthroplasty patients, the mesenchymal stem cells culture expanded and used for cellular analysis of substrate bioactivity.

The cell line specificity and osteogenic behaviour was demonstrated through immunohistochemistry, confirmed by real-time PCR and quantitative PCR. Mineralisation was demonstrated using alizarin red staining.

Results showed that the osteoinduction was optimally conferred by the presence of nanotopography, and also by the incorporation of hydroxyapatite (HA) into the PCL. The nanopit topography and HA were both superior to the use of BMP2 in the production of mineralised bone tissue.

The protocol from shim production to bone marrow harvesting and vertical cell culture on nanoembossed HaPCL has been shown to be reproducible and potentially applicable to economical larger scale production.

Infection rates following arthroplasty surgery are between 1–4%, with higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are considerable, with significantly worse functional outcomes reported. New methods of infection prevention are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthoplasty cases.

Specimens from hip and knee arthroplasty infections are routinely collected to identify causative organisms. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (123mW/cm² irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration.

Complete inactivation was achieved for all Gram positive and negative microorganisms

More than a 4-log reduction in Staphylococcus epidermidis and Staphylococcus aureus populations were achieved after exposure to HINS-light for doses of 48 and 55 J/cm², respectively. Current investigations using Escherichia coli and Klebsiella pneumoniae show that gram-negative organisms are also susceptible, though higher doses are required.

This study has demonstrated that HINS-light successfully inactivated all clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes.

Allogenic blood is a finite resource, with associated risks. Previous studies have shown intra-operative cell salvage (ICS) can reduce allogenic transfusion rates in orthopaedic surgery. However, recent concerns regarding the efficacy and cost-effectiveness of ICS mean we must continually re-assess its usefulness in current practice. This study was carried out to review the use of ICS, to establish if its use has led to a reduction in patient exposure to post-op allogenic transfusion.

All orthopaedic patients who underwent ICS and re-infusion between 2008–2010 in the Southern General Hospital (SGH) were audited. The Haemoglobin (Hb) drop, volume of blood re-infused and post-op allogenic transfusion rates were recorded. The revision hip group was compared to a similar SGH cohort, who underwent surgery by the same surgeons between 2006–2008, and a pre-2005 control group. The Cell Saver (Haemonetics) machine was used.

The proportion of patients who received a post-op allogenic transfusion fell by 55% in the 2008–2010 ICS cohort compared with the control, and by 40% compared with the previous ICS study group. In both instances, this was accompanied by a statistically significant (p<0.001) reduction in mean number of units transfused per patient.

ICS has been shown to be effective in reducing rates and volume of post-op allogenic transfusion in patients undergoing revision hip surgery at the SGH. ICS has been used with increasing efficiency over time.

Over 70,000 hip fractures occur annually in the UK. Both SIGN (111) and NICE (124) give guidance on optimal management of these patients. Both suggest cemented hemiarthroplasty should be used in those without contra-indications, as cemented implants are associated with less thigh pain, subsidence and a better functional outcome. Cardiorespiratory compromise secondary to bone cement implantation syndrome (BCIS) is however a concern in those with pre-existing cardiorespiratory disease (NYHA grade 3–4, pulmonary hypertension) or pathological fracture [3].

The aim of our study was to audit the practice of a University of Glasgow hospital with regard to cemented hemiarthroplasty.

We retrospectively reviewed data on all patients treated with hemiarthroplasty for hip fracture at the Southern General Hospital between 01/01/12-02/04/12. Patient demographics, pre-operative plan, procedure performed, ASA grade and pre-morbid mobility were recorded.

Repeat revision hip replacements can lead to severe bone loss necessitating salvage procedures such as proximal or total femoral replacement. We present medium term outcomes from our experience of the Limb Preservation System (LPS) in patients with failed revision hip arthroplasties.

All patients undergoing proximal femoral or total femoral replacement from 2003–2007 at our unit were reviewed. Data was collected preoperatively and at annual assessment post procedure for a minimum of 5 years. This included clinical review, functional outcome scores (WOMAC, Oxford Hip Score, Harris Hip Score) and radiographic evaluation.

A total of 17 patients underwent femoral replacement (13 proximal, 4 total) using the LPS during the study period. Within this cohort there were 13 males and 4 females with a mean age of 64 years (range 47–86). Median follow up was 7 years (range 5–9 years). Primary diagnoses were DDH (7), Primary OA (5), RA (2), proximal femoral fracture (2) and phocomelia (1). Five patients (29%) required further revision surgery for infection (2 patients) or recurrent dislocations (3 patients). No stems required revision due to aseptic loosening or stem failure at 5–9 years. Compared to preoperative assessment, there was significant improvement in median outcome scores at 5 years (WOMAC increased by 33 points, Oxford hip score by16 points and Harris hip score by 43 points). 82% of patients maintained functional independence at latest review.

The Limb Preservation System offers a salvage procedure for failed revision total hip arthroplasty with significant symptom and functional improvement in most patients at medium term follow up.

Metal on metal (MoM) bearings in hip surgery may result in increased blood levels of metal ions. The nature of the relationship between ion levels and failure is still not fully understood.

We compared three cohorts of resurfacing patients, grouped for brand and diameter of femoral component. We measured the blood level of Cobalt and Chromium ions at an average of 4 years postoperatively. The results were grouped as follows: Birmingham Hip Resurfacing ≥50 mm diameter, Durom resurfacing ≥50 mm diameter and Durom resurfacing <50 mm diameter.

120 patients were included in each group. There were significant differences in Cobalt levels between the groups. The median cobalt level for the BHR group was 8 nmol/L higher than the Durom ≥50 mm group (P<0.005). The Durom <50 mm group recorded cobalt levels 8.5 nmol/L higher than the Durom ≥50 mm group (P=0.0004). Revision rates were equal in the Large BHR's and Large Durom HRA (both 3.3%) however the small Durom HRA had a revision rate of 8.3%.

Elevated blood ion levels can indicate a failing MoM bearing. When similar ion levels were reported for BHR and small Durom the latter had significantly higher revision rates. The large BHR and large Durom HRA have similar revision rates yet the large Durom HRA had significantly lower metal ion levels. Only one of the patients having revision surgery (n=18) had metal ion levels above the MHRA threshold. This suggests ion levels do not absolutely predict the rate of HRA failure. Given similar revision rates with different ion levels between the large BHR and large Durom hips, mechanisms of failure leading to revision must be isolated from the release of metal ions. Therefore clinical and image based follow up are recommended in addition to ion level monitoring.

Polyetheretherketone (PEEK) is a thermoplastic polymer that is predominant in spinal surgery as the material of choice for spinal fusion cages, and is also used for bone anchors, cruciate ligament interference screws, and femoral stems. It has the distinct advantage of having similar mechanical properties to bone, but its clinical application as implant material is limited by a lack of bioactivity. This project aims to create an PEEK surface capable of osseointegration using a surface modification technique known as oxygen plasma treatment.

PEEK surfaces were injection molded, washed and then treated in a plasma chamber for up to 10 min. Surfaces were characterised using atomic force microscopy (AFM), scanning electron microscopy (SEM), water contact angle measurements and X-ray photo-electron spectroscopy (XPS). Human bone marrow cells were cultured on the surfaces and assessed for calcium production (using alizarin red stain).

Water contact angle measurements show that after plasma treatment, the surfaces become very hydrophilic, before developing a meta-stable state at approx. 6 weeks. AFM and SEM showed destruction of the nano-pits at treatment durations longer than 2 mins. XPS detected a progressive increase in the atomic proportion of oxygen at the surface with increasing plasma treatment duration. There was significantly less alizarin uptake (and hence calcium production) on the untreated PEEK compared to the plasma treated PEEK surfaces (p < 0.05).

These results show that oxygen-plasma treatment can increase calcium production on PEEK surfaces and may improve long term osseointegration of PEEK implants.

Infection rates following arthroplasty surgery are between 1–4%, with higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are considerable, with significantly worse functional outcomes reported. New methods of infection prevention are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthroplasty cases.

Specimens from hip and knee arthroplasty infections are routinely collected to identify causative organisms. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (123 mW/cm² irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration.

Complete inactivation (greater than a 4-log reduction) was achieved for all of the clinical isolates from infected arthroplasty cases. The typical inactivation curve showed a slow initial reaction followed by a period of rapid inactivation. The doses of HINS-light exposure required ranged from 118–2214 J/cm² respectively. Gram-positive bacteria were generally found to be more susceptible than Gram-negative.

This study has demonstrated that HINS-light successfully inactivated all clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes.

Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis in young active individuals but the pathophysiology remains unclear. Increasing mechanistic studies point toward an inflammatory component in OA. This study aimed to characterise inflammatory cell subtypes in FAI by exploring the phenotype and quantification of inflammatory cells in FAI versus OA samples.

Ten samples of labrum were obtained from patients with FAI (confirmed pathology) during open osteochondroplasty or hip arthroscopy. Control samples of labrum were collected from five patients with osteoarthritis undergoing total hip arthroplasty. Labral biopsies were evaluated immunohistochemically by quantifying the presence of macrophages (CD68 and CD202), T cells (CD3), mast cells (mast cell tryptase) and vascular endothelium (CD34).

Labral biopsies obtained from patients with FAI exhibited significantly greater macrophage, mast cell and vascular endothelium expression compared to control samples. The most significant difference was noted in macrophage expression (p<0.01). Further sub typing of macrophages in FAI using CD202 tissue marker revealed and M2 phenotype suggesting that these cells are involved in a regenerate versus a degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r=0.4, p<0.05) in FAI samples.

We provide evidence for an inflammatory cell infiltrate in femoroacetabular impingement. In particular, we demonstrate significant infiltration of mast cells and macrophages suggesting a role for innate immune pathways in the events that mediate hip impingement. Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement.

Osteogenesis is key to fracture healing and osteointegration of implanted material. Modification of surfaces on a nanoscale has been shown to affect cell interaction with the material and can lead to preferential osteogenesis. We hypothesised that osteogenesis could be induced in a heterogeneous population of osteoprogenitor cells by circular nanopits on a material surface. Furthermore, we intended to assess any correlation between nanopit depth and osteoinductive potential.

The desired topographies were embossed onto polycaprolactone (PCL) discs using pre-fabricated nickel shims. All pits had a diameter of 30μm and investigated pit depths were 80nm, 220nm and 333nm. Scanning electron microscopy confirmed successful embossing and planar controls were shown to be flat. A bone marrow aspirate was obtained from the femoral neck of a healthy adult undergoing a hip replacement. After establishing a culture, cells were seeded onto the PCL discs, suspended in basal media and incubated. Samples were fixed and stained after three and 28 days.

Cells were stained for the adhesion molecule vinculin after three days. Lowest concentrations of vinculin were seen in the planar control group. Osteoprogenitor cells on the shallowest pits, 80nm, had larger and brighter adhesion complexes. After 28 days, osteocalcin and osteopontin expression were used as markers of cell differentiation into an osteoblastic phenotype. 220nm deep pits consistently produced cells with the highest concentrations of osteopontin (p = 0.017) with a similar trend of osteocalcin expression. Cells on all topographies had higher expression levels than the planar controls.

We demonstrated stimulation of osteogenesis in a heterogeneous population of osteoprogenitor cells. This cell mix is similar to that present in fracture healing and after reaming for intramedullary devices or uncemented implants. All nanopit depths gave promising results with an optimum depth of 220nm after 28 days.

Introduction

The outcome of periacetabular osteotomy in dysplastic hips is dependent on the absence of pre-operative osteoarthritis [OA]. The purpose of this study was to analyze whether Tonnis grading is a reliable predictor of OA in patients with hip dysplasia.

Reconstruction of an acetabulum following severe bone loss can be challenging. The aim of this study was to determine the outcome of acetabular reconstruction performed using trabecular metal shell for severe bone loss.

Between June 2003 and June 2006 a total of 29 patients with significant acetabular bone stock deficiency underwent revisions using trabacular metal shell. According to Paprosky classification, there were 18 patients with grade IIIA and 11 patients with grade IIIB defects. Nineteen patients required augments to supplement the defects. Functional clinical outcomes were measured by WOMAC and Oxford hip. Detailed radiological assessments were also made.

At most recent follow up (average 5.5 years, range 3.5–8.5) the mean Oxford hip score improved from 12 preoperatively to 27.11 postoperatively and WOMAC score from 17.57 preoperatively to 34.14 postoperatively The osseointegration was 83% according to Moore's classification. There were two reoperations; one was for instability, and one for aseptic loosening. One patient has a chronic infection and one had a periprosthetic fracture, both treated conservatively.

Despite challenges faced with severe preoperative acetabular defects the early results using this technique in Grade III A and B is encouraging.

Infection rates following arthroplasty surgery are between 1–4%, with higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are considerable, with significantly worse functional outcomes reported. New methods of infection prevention are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthoplasty cases.

Specimens from hip and knee arthroplasty infections are routinely collected to identify causative organisms. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (123mW/cm2 irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration.

Complete inactivation was achieved for all Gram positive and negative microorganisms More than a 4-log reduction in Staphylococcus epidermidis and Staphylococcus aureus populations were achieved after exposure to HINS-light for doses of 48 and 55 J/cm2, respectively. Current investigations using Escherichia coli and Klebsiella pneumoniae show that gram-negative organisms are also susceptible, though higher doses are required.

This study has demonstrated that HINS-light successfully inactivated all clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes.

Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis in young active individuals but the pathophysiology remains unclear. Increasing mechanistic studies point toward an inflammatory component in OA. This study aimed to characterise inflammatory cell subtypes in FAI by exploring the phenotype and quantification of inflammatory cells in FAI versus OA samples.

Ten samples of labrum were obtained from patients with FAI (confirmed pathology) during open osteochondroplasty or hip arthroscopy. Control samples of labrum were collected from five patients with osteoarthritis undergoing total hip arthroplasty. Labral biopsies were evaluated immunohistochemically by quantifying the presence of macrophages (CD68 and CD202), T cells (CD3), mast cells (mast cell tryptase) and vascular endothelium (CD34).

Labral biopsies obtained from patients with FAI exhibited significantly greater macrophage, mast cell and vascular endothelium expression compared to control samples. The most significant difference was noted in macrophage expression (p<0.01). Further sub typing of macrophages in FAI using CD202 tissue marker revealed and M2 phenotype suggesting that these cells are involved in a regenerate versus a degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r=0.4, p<0.05) in FAI samples.

We provide evidence for an inflammatory cell infiltrate in femoroacetabular impingement. In particular, we demonstrate significant infiltration of mast cells and macrophages suggesting a role for innate immune pathways in the events that mediate hip impingement. Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement.

Introduction

Infection rates following arthroplasty surgery are reported between 1–4%, with considerably higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are over 4 times the cost of primary arthroplasties, with significantly worse functional and satisfaction outcomes. In addition, multiple antibiotic resistant bacteria are developing, so to reduce the infection rates and costs associated with arthroplasty surgery, new preventative methods are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process, and is proven to have bactericidal activity against a wide range of species. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthoplasty cases.

Metal-on-metal hip resurfacing prostheses are a relatively recent intervention for relieving the symptoms of common musculoskeletal diseases such as osteoarthritis. While some short term clinical studies have offered positive results, in a minority of cases there is a recognised issue of femoral fracture, which commonly occurs in the first few months following the operation. This problem has been explained by a surgeon's learning curve and notching of the femur but, to date, studies of explanted early fracture components have been limited.

Tribological analysis was carried out on fourteen retrieved femoral components of which twelve were revised after femoral fracture and two for avascular necrosis (AVN). Eight samples were Durom (Zimmer, Indiana, USA) devices and six were Articular Surface Replacements (ASR, DePuy, Leeds, United Kingdom). One AVN retrieval was a Durom, the other an ASR. The mean time to fracture was 3.4 months. The AVNs were retrieved after 16 months (Durom) and 38 months (ASR).

Volumetric wear rates were determined using a Mitutoyo Legex 322 co-ordinate measuring machine (scanning accuracy within 1 micron) and a bespoke computer program. The method was validated against gravimetric calculations for volumetric wear using a sample femoral head that was artificially worn in vitro. At 5mm3, 10mm3, and 15mm3 of material removal, the method was accurate to within 0.5mm3. Surface roughness data was collected using a Zygo NewView500 interferometer (resolution 1nm).

Mean wear rates of 17.74mm3/year were measured from the fracture components. Wear rates for the AVN retrievals were 0.43mm3/year and 3.45mm3/year. Mean roughness values of the fracture retrievals (PV = 0.754nm, RMS = 0.027nm) were similar to the AVNs (PV = 0.621nm, RMS = 0.030nm), though the AVNs had been in vivo for significantly longer.

Theoretical lubrication calculations were carried out which found that in both AVN retrievals and in seven of the twelve cases of femoral fracture the roughening was sufficient to change the lubrication regime from fluid film to mixed. Three of these surfaces were bordering on the boundary lubrication regime. The results show that even before the femoral fracture, wear rates and roughness values were high and the implants were performing poorly.

Raised blood pressures (BP) are associated with increased cardiovascular risks such as myocardial infarction, stroke and arteriosclerosis. During surgery the haemodynamic effects of stress are closely monitored and stabilised by the anaesthetist. Although there have been many studies assessing the effects of intraoperative stress on the patient, little is known about the impact on the surgeon.

A prospective cohort study was carried out using an ambulatory blood pressure monitor to measure the BP and heart rates (HR) of three consultants and their respective trainees during hallux valgus, hip and knee arthroplasty surgery. Our principle aim was to assess the physiological effects of performing routine operations on the surgeon. We noted if there were any differences in the stress response of the lead surgeon, in comparison to when the same individual was assisting. In addition, we recorded the trainee's BP and HR when they were operating independently.

All of the surgeons had higher BP and HR readings on operating days compared to baseline. When the trainer was leading the operation, their BP gradually increased until implant placement, while their trainees remained stable. On the other hand, when the trainee was operating and the trainer assisting, the trainer's BP peaked at the beginning of the procedure, and slowly declined as it progressed. The trainee's BP remained elevated throughout. The highest peaks for trainees were noted during independent operating.

We conclude that all surgery is stressful, and that trainees are more likely to be killing themselves than their trainers.

Cardiovascular disease is now the leading cause of morbidity and mortality worldwide. Raised blood pressures (BP) are associated with increased cardiovascular risks such as myocardial infarction, stroke and arteriosclerosis. During surgery the haemodynamic effects of stress are closely monitored and stabilised by the anaesthetist. Although there have been many studies assessing the effects of intraoperative stress on the patient, little is known about the impact on the surgeon.

A prospective cohort study was carried out using an ambulatory blood pressure monitor to measure the BP and heart rates (HR) of three consultants and their respective trainees during hallux valgus, hip and knee arthroplasty surgery. Our principle aim was to assess the physiological effects of performing routine operations on the surgeon. We noted if there were any differences in the stress response of the lead surgeon, in comparison to when the same individual was assisting. In addition, we recorded the trainee's BP and HR when they were operating independently. The intraoperative measurements were compared with their baseline readings and their stress response, assessed using the Bruce protocol.

Many trends were noted in this pilot study. All of the surgeons had higher BP and HR readings on operating days compared to baseline. The physiological parameters normalised by one hour post-theatre list in all subjects. When the trainer was leading the operation, their BP gradually increased until implant placement, while their trainees remained stable. On the other hand, when the trainee was operating and the trainer assisting, the trainer's BP peaked at the beginning of the procedure, and slowly declined as it progressed. The trainee's BP remained elevated throughout. The highest peaks for trainees were noted during independent operating.

We conclude that all surgery is stressful, and that trainees are more likely to be killing themselves than their trainers.

Hip resurfacing has generally been used in younger patients with early osteoarthritis of the hip. There has been considerable recent interest in this over the past few years. We conducted a prospective randomised trial comparing 2 hip resurfacing implants, Durom and ASR looking at radiological and clinical outcomes.

Forty-nine patients (78% male) with hip osteoarthritis which met the criteria for hip resurfacing were randomised to receive either a Durom or ASR resurfacing implant. These patients have so far been followed up for a minimum of one year. The groups were comparable in age (p=0.124) and gender (p=0.675). The average age in the ASR group was 54.04 years and in the Durom group it was 51.25.

Radiological views were scrutinised immediately post op and at final follow up so far to look at cup inclination, stem-shaft angle, and acetabular osseointegration.

Clinical outcomes were compared using the Oxford hip scores, WOMAC scores and SF12 scores.

At minimum follow up of 1 year the mean post operative Oxford hip score was not significantly different between the Durom (45.32, SD 3.93) and ASR (43.44, SD 8.44). The mean post operative WOMAC score was also not significantly different between the Durom (52.56, SD 6.06) and ASR (49.63, SD 2.23). There was no difference between the groups with regards to signs of osseointegration from radiological assessment (p=0.368). There were 3 periprosthetic femoral neck fractures (5.7%) and one revision for pain.

We conclude from this trial that there is no difference in the clinical or radiological findings between the Durom and ASR implants.

Prophylactic antibiotics administered prior to joint arthroplasty have become standard practice. Due to concern over the risk that 2nd generation cephalosporins posed to the elderly, as regards clostridium difficile associated infections the antimicrobial management team in our unit changed the protocol for prophylactic antibiotics. As of 1st September 2009, flucloxacillin and gentamicin were preferred over cefuroxime as the first choice of prophylactic antibiotic. However, it was noted that postoperatively patients were experiencing a decrease in renal function.

One hundred patients who underwent a total hip replacement following the policy change were randomly selected from the departmental joint arthroplasty database. This group was age and sex matched to 100 patients undergoing their surgery prior to the change. Data was collected on renal function, length of stay, antibiotic and age. Any change in renal function was categorised using the RIFLE criteria.

Exclusion secondary to variations from protocol or treatment for femoral neck fractures resulted in a total number of 156 patients with 78 in each arm. The average age for both groups was 64 years. Non-parametric analysis of preoperative and postoperative serum creatinine concentrations and Glomerular Filtration Rate (GFR) demonstrated a significant difference between the two groups, showing that GFR decreased (p=0.041) and serum creatinine concentration increased (p=0.037) in the cohort receiving gentamicin. Classing the impaired renal function as: risk, injury or failure (RIFLE criteria) demonstrated a statistically significant difference for any criterion positive (p=0.016) but no significant difference for the specific RIFLE groups (p=0.068).

Acknowledging the small numbers and potential confounders for renal impairment, this study was able to show a difference in renal function for patients receiving gentamicin over cefuroxime as prophylaxis for joint arthroplasty.

It is well established that cell behaviour is responsive to the surrounding environment. Chemistry, material stiffness and topography allow control of cell adhesion, proliferation, growth and differentiation. Biomimicry is playing a role in the next generation of biomaterials, surface engineering on orthopaedic implants may promote improved skeletal integration.

Human osteoblasts were cultured on engineered micro-topographical features with nanoscale depths, similar in scale to an osteoclast resorption pit. Three different micro-topographies were used (in addition to planar controls.) created on a hot moulded polymer. The cells were cultured in basal media on surfaces with 20, 30 and 40 micrometer circular pits, each with a depth of 400 nanometers. The cells were fixed at time points 3 days, 21 days and 28 days to allow assessment of cytoskeletal development, production of protein markers of bone production (osteopontin) and mineral deposition respectively.

At each time point greater indicators of cell activity and bone production were evident on the 30 and 40 micrometer structures as compared with the 20 micrometer structures and the planar controls. These positive results include increased focal adhesions, stronger expression of intracellular and extracellular osteopontin and more mature nodules of calcium formation.

This in vitro study demonstrates that micro and nanotopographies influence cell activity. Osteoblast response can be induced on the surface of a future generation of orthopaedic implants, lasting long after the effects chemical application have expired. Further research is required to assess the potential application to implant grade materials.

The objective was to compare vastus lateralis muscle splitting verses muscle sparing surgical approach to proximal femur for fixation of intertrochanteric fracture.

Of the 16 patients in this prospective randomised double blind study 8 were randomised to vastus lateralis muscle splitting and rest to muscle sparing group. Main outcome measurement was assessment of status of vastus lateralis muscle at 2 and 6 weeks using nerve conduction study. Preoperative demographics were identical for both the groups.

There was no statistically significant difference between the groups with regards to velocity, latency, and amplitude. The postoperative haemoglobin drop, heamatocrit, position of the dynamic hip screw and mobility status were identical.

Both clinical and neurophysiological outcome suggest that damage done to vastus lateralis either by splitting or elevating appears to be identical.

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.

Anterior knee pain following primary total knee replacement (TKR) is a common problem with average reported rates in the literature of approximately 10%. Symptoms are frequently attributed to the patellofemoral joint, and the treatment of the patella during total knee replacement is controversial.

There is no article in the literature that the authors know of that has specifically evaluated the effect of patella rim cautery on TKR outcome. This is a denervation technique that has historically been employed, with no evidence base. A prospective comparative cohort study was performed to compare the outcome scores of patients who underwent circumferential patella rim cautery, with those who did not.

Patients who had undergone a primary TKR were identified from the unit's arthroplasty database. Two cohorts, who were age and gender matched, were established. None of the patients had their patella resurfaced, but all had a patellaplasty. The Low Contact Stress TKR (Depuy International) was used in all cases.

The effect of circumferential patella rim cautery on the Oxford Knee Score (OKS) and the more anterior knee pain specific Patellar Score (PS) a minimum of 2 years post surgery was evaluated. Previous reports have suggested that a change of 5 points in the OKS represents a clinical difference. A sample size calculation based on an effect size of 5 points with 80% power and a p-value of 0.05 would require a minimum of 76 patients in each group.

There were 94 patients who had undergone patellaplasty only, and 98 patients who had supplementary circumferential patella rim cautery during their primary TKR. The mean OKS were 34.61 and 33.29 respectively (p=0.41), while the PS scores were 21.03 and 20.87 (p=0.87).

No statistically significant differences were noted between the groups for either outcome score. Patella rim cauterisation is unnecessary in primary TKR.

The diagnosis and treatment of hip disease in young adults has rapidly evolved over the past ten years. Despite the advancements of improved diagnostic skills and refinement of surgical techniques, the psychosocial impact hip disease has on the young adult has not yet been elucidated.

This observational study aimed to characterise the functional and psychosocial characteristics of a group of patients from our young hip clinic. 49 patients responded to a postal questionnaire which included the Oswestry Disability Index (ODI) and Hospital Anxiety and Depression Scale (HADS). Median age was 20 years (range 16-38) with a gender ratio of 2:1 (female: male). The most common diagnoses were Perthes' disease and developmental hip dysplasia. More than half of our patients had moderate to severe pain based on the Visual Analogue Scale (VAS) and at least a moderate disability based on the ODI. Thirty-two percent of patients were classified as having borderline to abnormal levels of depression and 49% of patients were classified as having borderline to abnormal levels of anxiety based on the HADS. Comparison of the ODI with the VAS and HADS anxiety and depression subscales showed a significant positive correlation (p<0.05). Multiple regression showed the ODI to be a significant predictor of the HADS anxiety and depression scores (regression coefficient 0.13, 95% confidence interval 0.06 to 0.21, p<0.05).

This study highlights the previously unrecognised psychosocial effects of hip disease in the young adult. A questionnaire which includes HADS may be of particular value in screening for depression and anxiety in young people with physical illness. This study also highlights that collaboration with psychologists and other health care providers may be required to achieve a multidisciplinary approach in managing these patients.

Revision total hip replacement is often associated with significant blood loss and subsequent transfusion. Intra-operative cell salvage is one approach to minimising this allogenic transfusion.

We carried out a retrospective study of 158 consecutive revision THRs carried out by one surgeon between June 2003 and September 2006 in the Southern General Hospital, Glasgow.

In the study group (79 patients, operated upon after October 2005) Intra-operative cell salvage was routinely used for all cases. In the control group (79 patients, operated upon before October 2005) Intra-operative cell salvage was not available.

Data was collected on transfusion of salvaged blood, transfusion of allogenic blood, operation type, indication for surgery, complications and length of hospital stay.

Results showed a 53% reduction (p=0.002) in the number of units of allogenic blood transfused in the study group compared with the control group. (1.59 units per case compared with 3.41 units).

In the study group 51% of patients received allogenic blood transfusion, compared with 68% of patients in the control group, a relative reduction of 17% (p=0.02).

There was no difference between the two groups regarding haemoglobin drop and length of hospital stay. Data regarding complications yielded no significant results due to small cohort size.

We conclude that intra-operative cell salvage leads to a significant reduction in allogenic blood transfusion with subsequent implications upon cost, resource management, and patient safety and should be used for all patients undergoing revision hip arthroplasty.

Infection following hip arthroplasty although uncommon can have devastating outcomes. Obesity, defined as a BMI of ≥ 30, is a risk factor for infection in this population. Coagulase negative staphylococcus aureus (CNS) is the commonest causative organism isolated from infected arthroplasties. This study was performed to determine if there has been a change in the causative organisms isolated from infected hip arthroplasties and to see if there is a difference in obese patients.

Data on all deep infection following primary and revision hips was obtained from the surgical site infection register from April 1998 to Nov 2007. Case notes were reviewed retrospectively. There were 49 patients with 51 infected arthroplasties; 25 infected Primary THAs and 26 infected Revision THAs. We found a female preponderance in the infected primary and revision THAs (n=30). 63.2% of all patients had a BMI of ≥ 30, compared to only 34.7% of the non infected population (p< 0.0001). Over the period studied, CNS was the most common organism isolated (56.8%) followed by mixed organisms (37.2%) and staphylococcus aureus (25.4%). Multiple organisms were found exclusively in obese patients. In more than half of cases the causative organisms were resistant to more than two antibiotics.

This study shows that over the last 10 years, CNS continues to be the most frequently isolated organism in infected hip arthroplasties. Multiple organisms with multiple antibiotic resistances are common in obese patients. On this basis we recommend that combination antibiotic therapy should be considered in obese patients.

Introduction: The ideal acetabular component has low wear, permanent fixation and physiological bone loading. Recently trabecular metal has been promoted as reproducing the modulus of trabecular bone with a cementless fixation. The aim of this trial was to see if a monobloc trabecular backed polyethylene acetabular component loaded the pelvis physiologically as a cemented polyethylene component.

Method: Between 2004 and 2006 54 patients were ran-domised to a cemented polyethylene acetabular component versus a monobloc trabecular backed polyethylene acetabular component. The primary outcome measurement was bone density in peri-prosthetic acetabular regions of interest measured preoperatively and post operatively at 6 weeks and 1 year. Secondary outcomes measured were radiographic and functional outcomes (HHS and Oxford score).

Results: Radiographically 8 patients in the trabecular group had a significant gap in zone II which resolved in 6 by 1 year. The cemented group had 3 patients with a radiolucent line (zone 1) at 1 year. HHS and OXFORD scores improved with no significant difference between the groups. Both groups had significant loss of bone density in the ilium and ischium. The trabecular group produced a significant increase in bone density in the superolateral region. The cemented group produced increased bone density in the superomedial region.

Discussions and Conclusions: There is a significant reduction in BMD for both groups in the upper pelvis and ischium in keeping with finite element modelling predictions. The press-fit group relative to the cemented group resulted in decreased BMD in the superomedial peri-prosthetic region. The trabecular monobloc cup therefore behaves more like a rigid cementless shell despite the properties of trabecular metal.

Introduction: Infection following hip arthroplasty although uncommon can have devastating outcomes. Obesity, defined as a BMI of ≥ 30, is a known risk factor for infection in this population. Coagulase negative Staph Aureus (CNS) is the commonest causative organism isolated from infected arthroplasties. This study was performed to determine if there has been a change in the causative organisms isolated from infected hip arthroplasties and to see if there is a difference in obese patients.

Methods: Data on all deep infection following primary and revision hips was obtained from the surgical site infection register from April 1998 to November 2007. All case notes were reviewed retrospectively.

Results: There were 49 patients with 51 infected arthroplasties; 25 infected Primary THAs and 26 infected Revision THAs. We found a female preponderance in the infected primary and revision THAs (n=30). 65.3% of all patients had a BMI of ≥ 30. Over the period studied, Coagulase negative Staph was the most common organism isolated (56.8%) followed by mixed organisms (37.2%) and Staph Aureus (25.4%). Multiple organisms were found exclusively in obese patients. In more than half of cases the causative organisms were resistant to ≥ 2 antibiotics.

Discussion: This study shows that over the last 10 years, CNS continues to be the most frequently isolated organism in infected hip arthroplasties. Multiple organisms with multiple antibiotic resistances are common in obese patients. On this basis we recommend that combination antibiotic therapy should be considered in obese patients.

Hip resurfacing preserves proximal femoral bone stock, optimises stress transfer to the proximal femur and offers inherent stability and optimal range of movement. The early results of metal–on-polyethylene resurfacing designs were poor and the resurfacing concept was largely abandoned. Modern metal-on-metal articulations enabled the introduction of a new generation of hip resurfacings with encouraging early results. In 1997 two of the authors developed a hip resurfacing system utilizing a metal-on-metal bearing. Our study reports on the clinical and radiological outcomes of the first 200 hips that were treated with the Durom hip resurfacing at an average follow up of 4.6 years (range 3.5–6).

Between May 2001 and December 2003, 200 consecutive hip resurfacings were performed on 189 patients, using the Durom hybrid metal-on-metal system. The average age of the patients was 50 years (range 22.5 – 72.3) and 119 were male. Patients were seen at 6 weeks and at 3, 6 and 12 months and annually thereafter for clinical and radiological evaluation. Clinical results were evaluated using the Harris Hip Score. A subjective assessment of patient satisfaction was obtained and patient activity was assessed using the UCLA activity score.

No patient was lost to follow up. There were no dislocations and no femoral neck fractures. One femoral component was revised due to aseptic loosening 3.9 years postoperatively. There was one late acute haematogenous infection that was successfully treated elsewhere by debridement and retention of the prosthesis. The mean Harris Hip Score improved significantly from 46.7 preoperatively to 94.4 postoperatively. The mean HHS constituents for pain, function and motion all were significantly improved from the preoperative values of 11.9, 25.7 and 4.2 to 41.8, 43.4 and 4.8 respectively following the resurfacing procedure. The mean UCLA activity score was 7.2 indicating a relatively active patient population and 179 hips were rated as excellent by the patients. No cup was considered radiographically loose. Extensive radiologic changes were observed around the femoral stem in 2.5% of the hips, with migration of the femoral component in one case and stem demarcation in 4 cases. All 5 patients maintained excellent function and had no hip pain. Pelvic osteolysis was observed in 2 cases. Neck remodelling changes were observed in 35 hips (17.5%). Kaplan-Mayer survivorship analysis demonstrated the rate of survival of the resurfacing components to be 99.5% (95% confidence interval 98.5 to 100) with revision for any reason as the endpoint.

Early results with the Durom resurfacing system appear encouraging. Although these should be regarded with caution, modern metal-on-metal hip resurfacing potentially offers the ultimate bone preservation and restoration of function in appropriately selected young patients.

Purpose: To evaluate the appropriateness of posterior blade plate ankle arthrodesis as a salvage procedure, in a complex subgroup of ankle trauma patients.

Methods: We retrospectively identified all patients who underwent an ankle arthrodesis from our prospectively collected trauma database at Vancouver General hospital from 1997 to 2005. We then extracted those who had blade plate arthrodesis via the posterior approach for previous failed fracture fixation or failed previous fusion. Demographics, pre arthrodesis diagnosis, previous surgeries, deformity and complications were recorded. Clinical examination was based on outpatient evaluation and physical evaluation. This was supplemented with radiological follow up to confirm union and outcome scoring using the AOFAS and SF36 systems.

Results: Sixteen patients were identified from the trauma database who had undergone posterior blade plate ankle arthrodesis. Of these thirteen were available for follow up. There average age was 47 years (range 23–63 years). The male to female ratio was 3:1. Three cases were for failed previous ankle fusion by other means. Of the remaining ten patients with post traumatic osteoarthritis, seven had previous pilon fractures, two talar fractures and one fracture dislocated ankle. All cases went onto bony union. Patient satisfaction was good although functional outcome scoring was not normal

Conclusion: We have found this procedure to have several excellent benefits. It allows the surgeon to operate through virgin skin, reducing potential wound complications, and achieve good soft tissue coverage. The blade plate allows reconstitution of a normal plantar grade ankle and distal tibial orientation, when secured appropriately to bone. Excellent compression and union can be achieved with the AO compression device, but it’s important to have a second screw in the talus to prevent blade pull out. The procedure has good satisfaction among patients following previous failed surgery, as a salvage procedure.

To determine if intraoperative positioning in the supine or lateral position affects morbidity and mortality in orthopaedic trauma patients with femur fractures.

Retrospective cohort study of 991 patients representing 1030 femoral shaft fractures admitted to our level one trauma center between the years of 1987 to 2006. Primary outcome measures included mortality and admission to ICU. Secondary outcome measures included length of stay in hospital, length of time admitted to the intensive care unit and discharge disposition. Logistic regression analysis was performed to compare to effect of intraoperative position in addition to other known dependent variables on primary and secondary outcome measures.

Intraoperative position in the supine or lateral position had no effect on morbidity or mortality in orthopaedic trauma patients with femur fractures.

There is no difference in immediate mortality or morbidity between patients with femur fractures treated with IM nails in either the lateral or supine position. We conclude that either position is safe for the surgical stabilization of femur fractures and intraoperative position should be determined by surgeon preference.

Unlike metal-on-Polyethylene, metal-on-metal (MoM) implants seem to affect the adaptive immune response as evident from the associated perivascular infiltrate containing lymphocytes and plasma cells. This is more pronounced in implant failure secondary to aseptic loosening, and may represent the failure mode. A reduction in CD8+ T lymphocyte counts has also been described with Hip Resurfacing. MoM articulations produce a much smaller order of size of wear particles (nanoparticles) than metal-on- Polyethylene, which may be responsible for the observed adaptive immune system effects. We therefore analyzed the effects of CoCr nanoparticles (CoCrNP) on Dendritic Cells, T cells & B cells.

We produced CoCrNP using repetitive short spark discharges between electrodes of prosthetic CoCr alloy. Electron micrography and Brunauer-Emmet-Teller method both confirmed nanoparticle size. The following experiments were then undertaken.

Dendritic Cells were cultured from mouse bone marrow and incubated with CoCrNP of varying concentrations for 24hrs, or lipopolysaccharide as a positive control. Activation status was then characterized by CD40 expression on fluorescence activated cell sorting (FACS) analysis.

We found CoCrNP did not significantly increase CD40 expression on DCs, neither did it alter CD40 or CD86 expression on B cells. Using a sublethal concentration of CoCrNP as determined from the viability tests, CoCrNP inhibited CD3 & CD3/CD28 dependent T-cell proliferation. This would indicate CoCrNP reduces T cell proliferation and/or survival, which may explain the observed reduction in CD8+ count with hip resurfacing. Understanding the development of the Peri-vascular infiltrate associated with MoM implants will however, probably require more complex (most likely in vivo) models.

Background: Increased use of metal on metal (MOM) hip replacements has stimulated interest in immunological effects of chronic CoCr elevation. Unlike metal-on-polyethelylene, MOM implants are associated with a perivascular infiltrate of lymphocytes & plasma cells. This may be the mode of failure of MOM implants. A reduction in CD8+ T lymphocyte counts associated with MOM implants has previously been described. CoCr therefore seems to affect the adaptive immune response even though it is not a proteinous antigen.

We therefore analyzed the effects of CoCr particles on T cells & B cells. We also analyzed it effects on dendritic cells, which are the key antigen presenting cells to T helper cells.

Methods: CoCr nano particles were produced by repetitive short spark discharges between electrodes of prosthetic CoCr alloy. Electron micrography & BET both confirmed nanoparticle size.

Dendritic cells (DCs) were harvested from mouse bone marrow & cultured in medium supplemented with GM-CSF for 6 days, generating DCs typically 80–90% CD11c+. These were incubated with CoCr in concentrations of 25, 10 & 2.5 μg/ml, for 24 hours, or lipopolysaccharide 1 μg/ml as a positive control. Following incubation, activation status of CD11c+ DCs was characterized by MHC Class II, CD40, CD80 & CD86 expression by FACS analysis.

T-Lymphocytes were harvested from mouse lymph nodes & cultured in medium without phenol red. These were incubated at 5 ×105 cells/well with either CoCr, conA (positive control) or CoCr + conA & repeated using 2.5 ×105 cells/well. Other positive controls (CD3 & CD 28) were studied in repeating the experiment. At 48 hours Almar Blue was added & further incubation for 24 hrs. Light absorbance at 570nm & 600nm was then used to determine T cell proliferation

B-Lymphocytes were harvested from the lymph nodes of mice which were only able to mount a B-cell reaction to Hen egg Lysozyme (HEL). These were incubated with medium with CoCr, HEL (positive control) or CoCr+ HEL. The concentration of the CoCr was varied between 25, 10 & 2.5 μg/ml. FACS analysis for markers of B cell regulation was performed after 48 hours incubation..

Results: CoCr did not significantly increase CD 40 expression on DCs, although such expression was increased significantly by lipopolysaccaride CoCr did not significantly up or down regulate B cells as compared to the effects of HEL. CoCr did inhibit proliferation of T-cells & this was more pronounced where the ratio of CoCr/cell density was higher.

Conclusion: Both dendritic & B cells are unaffected by CoCr in vitro. However, CoCr inhibited T cell proliferation. This demonstrates the observed reduction in CD + T cells are probably due to a direct effect of CoCr, & not mediated through another cell type. The perivascular response to MOM implants on the other hand probably requires cell interaction in an in vivo environment.

Introduction: Removal of well-fixed, cementless, acetabular components after resurfacing hip arthroplasty remains a challenging problem. Damage to host bone may limit options for reconstruction, compromise the long-term result of the revision operation and fundamentally defeat the aim of bone conserving resurfacing hip surgery.

Methods: A series of 6 consecutive patients who under-went removal of a secure, acetabular resurfacing component at the time of revision arthroplasty were included for review. During the operative procedure, the size of the component which was removed and the diameter of the final reamer used prior to implantation and final acetabular implant were recorded. The modification of the standard explant technique will be described which allows safe removal of any size of acetabular component.

Results: In all patients the indication for index arthroplasty was osteoarthritis. Three cases were MMT (Smith and Nephew), 2 Cormet 2000 (Corin, UK). and 1 DUROM (Zimmer). The indications for acetabular revision were infection in all cases. The median difference between the size of component removed and the size of final component implanted was 4 mm.

Discussion: Our modification uses a pre-existing system. The ease of removal with this modification and the lack of any further damage to the host bone illustrates that the Explant Acetabular Cup Removal System can be safely expanded to removal of well fixed resurfacing monoblock acetabular components. With experience, any manufacturers resurfacing shell can be removed with virtually no bone loss.

Intraosseous schwannoma is a rare benign neoplasm, which most commonly arises in the head and neck region particularly the mandible, due to the long intraosseous path of sensory nerves in the mandible. We present a 27-year-old lady with an unusual presentation of an intraosseous schwannoma of the first metatarsal. There is only one report published previously of an intraossous schwannoma of the lesser metatarsal bone of the foot.

A 27-year-old woman presented with painful left forefoot following a trip while walking. Plain radiographs demonstrated a pathological fracture through a lytic lesion of the first metatarsal of the left foot. MRI scan using axial T1-weighted spin echo and axial and sagittal T2-weighted gradient echo showed an amorphous mass occupying the medulla of the bone but with a breach of the plantar aspect of cortex with apparent localised destruction. Ultrasound-guided biopsy was performed. Haematoxylin and Eosin stained specimen sections showed a proliferation of spindle cells of alternating hypercellularity and hypocellularity. This case was managed by curettage and grafting with autograft and synthetic bone substitute. At two-year follow-up, the radiographs showed complete graft incorporation and a healed cyst. The patient was clinically asymptomatic with return of full functions. There were no clinico-radiological findings to suggest any recurrence.

Due to rarity and non-specific clinico-radiological features, this case illustrates the necessity of a multi-disciplinary approach with an accurate histological diagnosis in combination with radiological and clinical appearances.

Introduction: Hip resurfacing is a popular alternative to total hip arthroplasty. It aims to provide more physiological loading of the proximal femur, avoiding stress shielding and associated bone resorption. However, finite element analysis of hip resurfacing systems suggests stress shielding occurs in the femoral neck below the prosthesis and theoretically may lead to femoral neck fracture. Nevertheless, recent DEXA studies indicate femoral bone stock preservation with no evidence of stress shielding. It is not yet known what actually occurs in clinical practice. The aim of this study was to assess whether femoral neck resorption occurs in one particular type of hip resurfacing post operatively and quantify the degree of narrowing.

Methods: Femoral neck resorption of the Cormet 2000 metal-on-metal resurfacing prosthesis (Corin, UK) was assessed by measuring the prosthesis-neck ratio on postoperative radiographs. 39 prostheses (35 patients) were measured on plain AP pelvis radiographs taken immediately and mean 2 years post-operatively. Subsequent follow up radiographs were measured up to maximum 7 years follow up, mean 4.75 years.

Results: There was evidence of neck atrophy in 35/39 hips at an average of 2 years post operation, with the overall average neck narrowing from a ratio of 0.86 to 0.81 at 2 years. Average neck ratios were calculated up to 7 years post resurfacing; 25 hips measured at 3 years average ratio of 0.81, 20 at 4 years ratio 0.8, 25 at 5 years ratio 0.8, 9 at 6 years ratio 0.8, 1 at 7 years ratio 0.81.

Discussion: A degree neck resorption occurs with this resurfacing prosthesis by 2 years, however no further resorption appears to occur beyond this, to a maximum follow up of 7 years. This may indicate that early narrowing is more likely to be due to harmless bone adaption then a progressive absorption jeopardising the femoral neck.

Introduction: Aseptic osteolysis represents a significant challenge to the orthopaedic surgeon as it limits the long terms survivorship of prosthetic implants.

Aim: To investigate whether the bisphosphonate aledronate alters the cytokine profile in the psuedomembrane excised from individuals undergoing revision hip arthroplasty surgery for aseptic failure.

Methods: A prospective, double-blinded, randomised controlled trial was conducted with relevant ethical approval. 10 patients were randomly assigned to receive a placebo or alendronate 70mg for a 6 week period prior to revision surgery. All individuals had aseptic failure of primary cemented femoral stems and acetabular cups with UHDPE inserts. Infection was excluded in all individuals prior to surgery. Multiple tissue samples were subsequently excised at surgery and sent for histology and culture. If either was subsequently positive for infection the individual was excluded from the study. Tissue samples were preserved using liquid nitrogen and formalin. Frozen tissue was stored at −70^oC pending Polymerase Chain Reaction analysis. Formalin preserved samples were paraffin sectioned for immunohistochemical analysis. PCR was carried out to assess expression of mRNA for Interleukins 1,6,17,18; TNF alpha, RANK-L, OPG and RANK. IHC was performed to confirm protein expression in the pseudomembrane excised from the femur and acetabulum. Multiple samples were used in each patient.

Results: In the 5 individuals who received the placebo there was expression of mRNA and protein for Interleukins 1,6,17,18; TNF alpha; RANK-L; OPG and RANK in all cases. There was no statistically significant difference in the expression of any of the aforementioned cytokines/receptors in the group receiving alendronate.

Discussion: A six seek course of oral alendronate 70mg had no effect upon osteoclastogenic cytokine expression when compared to the placebo group. This would suggest that alendronate may offer little benefit in reversing established particle induced osteolysis.

Introduction: Despite clinical history, examination and plain radiography it is occasionally difficult to locate the origin of hip pain. This is particularly relevant where the management will be a total hip arthroplasty. Local anaesthetic arthrogram of the hip may provide a simple, safe and reliable test to determine if the hip is the source of the patient’s symptoms. The aim of this study was to establish the use of this investigation in the management of hip pain.

Methods: All local anaesthetic hip arthrograms were reviewed from 1999 to 2005. All patients had completed a pain questionnaire following the arthrogram. Patients were classified into 3 groups; 1) Mild osteoarthritic changes on plain radiographs with possible referred pathology; 2) Minimal radiological changes but no obvious other pathology to refer pain; 3) Previous hip arthroplasty with unexplained pain. Those who subsequently had a primary or revision hip arthroplasty were assessed post-operatively by means of the Oxford hip score.

Results: Fifty-seven patients in total underwent a local anaesthetic hip arthrogram. From all the groups 34 patients obtained pain relief and 24 proceeded to primary or revision hip arthroplasty. Twenty three (96%) had a satisfactory post-operative outcome at an average follow-up of 2 years (average Oxford score 28). The remaining 10 patients with positive arthrograms are still waiting for surgery. All negative arthrogram patients were successfully discharged.

Discussion: A positive response to local anaesthetic hip arthrogram predicts a successful response to surgery. This permits accurate information of the results of hip surgery to be given to patients and aids in a management plan for a group of patients that can be otherwise challenging.

The long-term results of patients with multiple knee ligament injuries, i.e. at least 3 ligament ruptures, including both cruciates, in patients entered prospectively onto the trauma database between 1985 and 1999, were reviewed. Forty patients with this injury had modified Lysholm scores at long term follow-up a mean of 8 years post-injury. The mode of operative treatment fell into 3 groups: direct suture or screw fixation of avulsions (Group 1), mid-substance ruptures treated with cruciate reconstruction with hamstring tendons (Group 2), or suture repairs of mid-substance ruptures (Group 3). All operative procedures were undertaken within 2 weeks of injury. Non-operative treatment involved a cast or spanning external fixator (2–4 weeks) followed by bracing. Statistical analysis was performed on the Lysholm scores.

The 40 patients in the study group were predominantly young males, 40% had polytrauma, 33% had isolated injuries. Thirteen patients (33%) had non-operative management, the remainder had early operative treatment of their ligament injuries, tailored to the type of ligament injuries identified.

Long-term patient outcome data shows statistically significant differences (p< 0.05) between the best results, in patients with direct fixation of bony avulsions (mean = 89), followed by those who had early hamstring reconstruction (mean = 79), followed by those who underwent simple ligament repairs (mean = 65). There was a statistically significant difference (p< 0.05) between the overall scores for the operative group (mean = 80) compared with the non-operative group (mean = 50).

Operative treatment of multiple ligament injuries, particularly fixation of avulsions and primary reconstruction of the posterior cruciate ligament appears to yield better results than non-operative or simple repair in the long term follow-up in this group with significant knee injuries.

This study evaluated the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty. One hundred and twenty-six patients who underwent consecutive revision of total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. WOMAC, Oxford-12, SF-12 and patient satisfaction data were obtained at a minimum of two years follow-up. Follow-up was obtained in one hundred and ten patients. There was no significant difference between the two cohorts with regards to outcomes. A patellar prosthesis does not appear to significantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty.

The purpose of this study is to evaluate the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty in a matched cohort study.

The presence or absence of a patellar prosthesis does not appear to significantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty.

Attempting to resurface the patella in revision cases may not be worthwhile.

Follow-up was obtained in one hundred and ten patients (fifty-two with patellar component, fifty-eight bony shell), matched for age, sex and co-morbidity scores and followed for a minimum of two years. There was no significant difference between the two cohorts with regards to outcomes of WOMAC pain (mean seventy-two and sixty-five, p=0.17), WOMAC function (mean sixty-four and fifty-nine, p=0.26) scores, Oxford −12 (mean sixty-three and sixty-seven, p=0.2), SF-12 (mean forty and thirty-six, p=0.27) and satisfaction outcomes (mean eight and nine, p=0.07), (power of 0.8, beta=0.2).

From January 1997 to December 1999 one hundred and twenty-six patients who underwent consecutive revision total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. At a minimum of two years follow-up, pain and function were assessed by questionnaire for WOMAC, Oxford-12, SF-12 and patient satisfaction data. Co-morbidity, surgical exposure, HSS knee scores and ROM were also collected. Univariate and multivariate analyses were performed.

It is questionable whether patient’s pain, function and satisfaction are affected in revision total knee arthroplasty by patellar prosthetic resurfacing.

Funding: One or more of the authors has received funding from a commercial party. This was DePuy, Inc, Warsaw, IN.

A concern with diaphyseal-fitting cementless stems in revision total hip arthroplasty is intra-operative fractures. Two hundred and eleven patients consecutively underwent revision hip arthroplasty using Solution stems (DePuy, Warsaw, IN). Intra-operative fractures or perforations occurred in sixty-four patients (30% prevalence), with diaphyseal splits in thirty-nine patients (18% prevalence). Risk factors were pre-operative osteolysis, cortex to canal ratio, under-reaming the cortex and large diameter stems. The majority of diaphyseal linear cracks occurred at the distal end of extended trochanteric osteotomies during stem insertion. Intra-operative fracture is associated with an average two days longer length of stay (p< 0.05).

The purpose of this study was to determine the identification of the risk factors and outcomes of intra-operative fractures using a diaphyseal fitting revision stem.

There is an association of intra-operative fracture associated using a diaphyseal-fitting stem in revision total hip arthroplasty with a longer length of stay in hospital.

Identifying preoperative risk factors will allow avoidance of such fractures and prolonged hospital stay.

Intra-operative fractures or perforations occurred in sixty-four patients (30% prevalence) and thirty-nine patients (18% prevalence) sustained diaphyseal splits. Risk factors associated with intra-operative fracture were pre-operative osteolysis, a low cortex to canal ratio, under-reaming the cortex and the use of a large diameter stem. Surgical approach was not directly related to fracture occurrence but the majority of diaphyseal undisplaced linear cracks occurred at the distal end of extended trochanteric osteotomies during stem insertion. Cortical perforation occurred most often with cement removal. Duration of stay was on average two days longer (p< 0.05) for patients with an intraoperative fracture.

Two hundred and eleven patients who had undergone revision hip arthroplasty using the Solution stem (DePuy, Warsaw, IN) between December 1998 and March 2002 were identified. Patients who sustained an intra-operative fracture were compared to controls patients who underwent hip revision at the same time frame but with no fracture. Multiple factors were analyzed to see which were risk factors for intra-operative fractures.

There is a surprisingly high incidence of intra-operative fracture associated with using a diaphyseal-fitting stem in revision total hip arthroplasty. This was associated with a longer length of stay

Patient satisfaction is not uniform or consistent following revision total knee arthroplasty. This study evaluates ninety-nine patients with a self-administered patient satisfaction questionnaire at a minimum of two years following the revision procedure (1997–99) to determine differences between satisfied (sixty-six patients) and dissatisfied patients (thirty-three patients). Univariate analysis revealed that patients satisfied with their results were significantly different (p< .05) than dissatisfied patients with regards to post op scores including those of the WOMAC pain and function, oxford, and SF-12. Patients were not different with regards to (p> .05) age, comorbidity score, surgical approach, or sepsis as a reason for the revision procedure. Regression analysis demonstrated that gender, post-op WOMAC score, and pre-op arc of motion were significant determinants of satisfaction.

The purpose of this study is to evaluate determinants of patient satisfaction following revision total knee arthroplasty.

Patient satisfaction with revision knee surgery is most strongly associated with both pre and post-operative descriptors of knee function as well as gender.

Understanding the variables associated with satisfaction/dissatisfaction following revision knee arthroplasty may further assist ongoing research efforts to improve the outcomes of this procedure.

Univariate analysis revealed that patients satisfied with their results were significantly different (p< .05) than dissatisfied patients with regards to WOMAC pain and function score, oxford knee score, and SF-12. Patients were not different with regards to (p> .05) age, comorbidity score, surgical approach, or presence of sepsis as a reason for the revision procedure. Regression analysis demonstrated that gender, post-op WOMAC score, and pre-op arc of motion were significant determinants of satisfaction (p< .05).

A self-administered patient satisfaction survey was completed by ninety-nine patients at a minimum of two years following revision total knee arthroplasty. Fifty-nine patients were females and forty were males. Sixty-six patients were satisfied and thirty-three patients were dissatisfied with the outcome of their surgery at two years post-op. Univariate analysis and multivariate regression suggest that pre and post-operative joint function and gender are the most significant determinants of patient satisfaction

The purpose of this study is to evaluate the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty in a matched cohort study.

From January 1997 to December 1999 126 patients who underwent revision of total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. At a minimum of two years follow-up, pain and function were assessed by questionnaire for WOMAC, Oxford-12, SF-12 and patient satisfaction data. Co-morbidity, surgical exposure, HSS knee scores and ROM were also collected. Univariate and multivariate analysis were performed. Follow-up was obtained in 110 patients (52 with patellar component, 58 bony shell), matched for age (mean 70 and 67 years), sex and co-morbidity scores and followed for a minimum of two years. There was no significant difference between the two cohorts with regards to outcomes of WOMAC pain scores (mean 66 and 74, p=0.14), WOMAC function scores (mean 59 and 65, p=0.22), Oxford- 12 scores (mean 57 and 64, p=0.17), and satisfaction score outcomes (57 and 68, p=0.14). It remains controversial whether the patient’s pain, function and satisfaction are affected in revision total knee arthroplasty by patellar prosthetic resurfacing. Insufficient patellar bone stock may preclude prosthetic resurfacing in which case patel-loplasty is performed. From this series, the presence or absence of a patellar prosthesis does not appear to sig-nificantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty.

There are a variety of surgical approaches available for open reduction and internal fixation of acetabular fractures. Some centres have avoided the use of the triradiate approach in the belief that it may result in a significantly higher rate of heterotopic ossification. This has not been our experience. In contrast to many centres, acetabular fractures are treated in an emergent manner, with surgery usually undertaken within the first few days post injury. It is the investigators’ belief that this may in part result in a lower rate of heterotopic ossification.

The triradiate approach has fallen out of favour in the treatment of acetabular fractures due to concerns with both wound healing and heterotopic ossification. This approach however has been utilised frequently at the Vancouver General Hospital (VGH) in the treatment of acetabular fractures. The purpose of this study was to review the results and complications of this approach experienced in the large series at VGH.

We concluded that the results of this approach are acceptable with the exposure allowing anatomical fracture reduction in the vast majority of cases. The complication rate was low, as was the rate of heterotopic ossification.

The significance of this study is to highlight that this approach remains extremely useful in the treatment of acetabular fractures, due to its ability to give excellent exposure while still having an acceptably low complication rate. We believe that the ability of our unit to operate on these injuries in an emergent manner may impart the low rate of heterotopic ossification that we have observed.

There were a total of one hundred and sixty-one acetabular fractures that were treated operatively with the triradiate approach over the period 1989 to 2001. Of these, the majority were two column injuries (79 or 49%), T type fractures (34 or 21%) and transverse fractures (17 or 11%). The average age of the patients was thirty-seven years and the average time to surgery was three days. Our early complications included five cases of failure of fixation or loss of reduction of the fracture, two cases of neurovascular injury, two cases of superficial wound infection, one case of deep wound infection and one case of wound breakdown.

The study involved examining patient hospital records and radiographs and included fracture types, patient ages, delay to surgery, post-operative complications and degree of fracture reduction and healing. Grading of heterotopic ossification was performed by reviewing the anteroposterior radiographs and using Gruen’s classification system.

Purpose: To evaluate early and late perioperative complications and long term quality of life outcomes in patients having undergone immediate open reduction and internal fixation of acute high-energy tibial plateau fractures (AO C3).

Methods: Retrospective review of 70 AO C3 tibial plateau fractures managed with immediate open reduction and internal fixation at the Vancouver General Hospital from December 1987 to April 2004. Chart and database review was conducted for early and late perioperative complications, and patients were surveyed using three quality of life instruments: SF36, SMFA, and WOMAC.

Results: 3(4.3%) patients had died at the time of follow-up. Of the remaining 67, 49(73%) could be located and were contacted for follow-up. 28 of the 49 subjects (57%) completed the mail-out surveys (20 male, 8 female). Mean age of respondents at time of follow-up was 45.2±9.0 years. 10(36%) patients were pedestrians or cyclists struck by cars, 9(32%) were injured as a result of a fall, 5(18%) were motor vehicle collisions, 2(7%) were sustained by a direct blow, and 2(7%) were sustained by twisting mechanisms. Mean time from injury to OR was 56.0+84.3 hours. Duration of follow-up was 8.9+5.3 years. 4(14%) patients had open fractures. Fixation methods included immediate ORIF with a single plate in 24(86%) cases, dual plating in 3(11%) cases, and screws alone in one (3%) case. ISS and LOS scores were 11.4+6.8 and 15.7+8.0 respectively. One patient (3%) experienced an early perioperative complication of excessive soft tissue tension post ORIF requiring delayed skin closure. Late perioperative complications included 9(32%) cases of painful hardware, 2(7%) non-unions, 2(7%) superficial infections, 1(3%) osteomyelitis and 1(3%) mal-union. No patients required amputation. SMFA and WOMAC scores were 55.3+9.6 and 29.44+23.22. SF36v scores were 40.6+10.4(PCS) and 45.1+15.8(MCS).

Conclusions: Immediate open reduction and internal fixation with careful attention to soft tissues can be a viable management option for many high energy tibial plateau fractures. Complication rates are comparable to those of delayed definitive management of these injuries.

Introduction and Aims: The use of the triradiate approach has been associated with high rates of wound dehiscence, wound infection and significant heterotopic ossification. This approach has been the favoured extensile exposure at the Vancouver General Hospital for many years. We will review the outcomes of the use of this approach in the treatment of acetabular fractures.

Method: Patients were identified from the database at Vancouver General Hospital who had their acetabular fractures treated through a triradiate approach from the period January 1989 through to December 2001. Patients with a delay of greater than three weeks from injury were excluded. A retrospective review of the hospital and out-patient records and all available radiographs was performed. Patients were contacted to determine if they required any further surgery and to assess their current functional status with appropriate outcome scores. Patients were also invited to undergo repeat radiographic assessment.

Results: Of a total of 407 acetabular fractures treated surgically, 152 open reductions were performed through the triradiate approach. The average age of these patients was 38 years and 114 (75%) of these were male. Patients referred from other hospitals totalled 128 (84%). Wound outcomes were known in 138 cases. Wound complications included five cases of wound dehiscence, of which four resolved with no undue effects. There were three cases of superficial wound infection and five cases of deep wound infection. Two of the patients with deep wound infection had sustained compound acetabular injuries and a further two had significant risk factors for infection (septicaemia from chest infection and significant soft tissue necrosis). Trochanteric osteotomy was performed in 139 (91%) cases. There were only two cases of trochanteric non-union in this series, however 21 cases required removal of painful trochanteric screws. With respect to heterotopic ossification, there was a 15% Broker III/IV incidence. In this group, the injury severity scores were higher, there was a greater delay to surgery and there was a greater need for mechanical ventilation due to multiple injuries. In the group, 24 hip reconstructions were required over the period.

Conclusion: In our centre, we found a low rate of wound dehiscence and deep wound infection associated with the triradiate approach in the treatment of acetabular fractures. Both open acetabular fractures developed deep infection. Trochanteric irritation was a problem in a number of the patients. The rate of significant hetero-topic ossification was low.