Introduction

The Best Practice Tariff (BpT) for primary THR / TKR was established in 2014 and rewards good clinical practice with a £550 uplift on the £5000 basic reimbursement. For an ‘average unit’ performing 220 primary THR and 260 eligible knee surgeries (NJR data) this equates to £265,000 per year or over £1million since its inception. The aim of this study was to investigate why Chelsea & Westminster Hospital NHS Trust was not receiving this reimbursement.

To date, there are no clear guidelines from the National Institute of Clinical Excellence or the British Orthopaedic Association regarding the use of Autologous Blood Transfusion (ABT) drains after elective primary Total Knee Replacement (TKR). There is little evidence to comparing specifically the use of ABT drains versus no drain. The majority of local practice is based on current evidence and personal surgical experience.

We aim to assess whether the use of ABT drains effects the haemoglobin level at day 1 post-operation and thus alter the requirement for allogenic blood transfusion. In addition we aim to establish whether ABT drains reduce post-operative infection risk and length of hospital stay.

Forty-two patients undergoing elective primary TKR in West London between September 2011 and December 2011 were evaluated pre- and post-operatively. Patient records were scrutinised. The patient population was divided into those who received no drain post-operatively and those with an ABT drain where fluid was suctioned out of the knee in a closed system, filtered in a separate compartment and re-transfused into the patient.

Twenty-six patients had ABT drains and 4 (15.4%) required an allogenic blood transfusion post-operatively. Sixteen patients received no drain and 5 (31.3%) required allogenic blood. There was no statistical difference between these two groups (p=0.22). There was no statistical difference (p=0.75) in the average day 1 haemoglobin drop between the ABT drain and no drain groups with haemoglobin drops of 2.80 and 2.91 respectively. There was no statistical difference in the length of hospital stay between the 2 groups (p=0.35). There was no statistical difference (p=0.26) in infection rates between the 2 groups (2 in ABT drains Vs. 0 in no drains). Of the 2 patients who experienced complications one had cellulitis and the other had an infected haematoma, which was subsequently washed out.

The results identify little benefit in using ABT drains to reduce the requirement for allogenic blood transfusion in the post-operative period following TKR. However, due to small patient numbers transfusion rates of 31.3% in the ABT drain group Vs. 15.4% in the no drain group cannot be ignored. Therefore further studies including larger patient numbers with power calculations are required before a true observation can be identified.

Introduction

Subtle deformities of the acetabulum and proximal femur are recognised as biomechanical risk factors for the development of hip osteoarthritis (OA) as well as a cause of hip and groin pain. We undertook this study to examine relationships between a number of morphological measurements of the acetabulum and proximal femur and the hip pain in a 20-year longitudinal study.

Introduction

Tissue diagnosis is essential to direct the definitive management of a suspected soft tissue or bone sarcoma tissue. Knowledge of both the diagnostic yield and accuracy of core needle biopsies is therefore important to give the investigating team information on the likelihood of their initial investigations achieving a diagnosis.

A femoral head/neck ratio (HNR) of less than 1.27 is associated with an increased risk of arthritis. The aim of this study was to establish whether there is evolutionary evidence that the homonin, bipedal stance has led to alterations in HNR that predispose humans to osteoarthritis (OA).

Specimens provided by The Natural History Museums of London, Oxford and the Department of Zoology, University of Oxford were grouped according to gait pattern, HAKF (Hip and knee flexed), Arboreal (ability to stand with hip and knee joints extended) and homonin/bi-pedal. Specimens included those from Devonion, Triassic, Jurrasic, Cretaceous, Miocene, Paleolithic, Pleistocene periods to modern day. Three-dimensional skeletal geometries were segmented using CT images and HNR measurements were taken from coronal views. These were compared with the HNR of 119 asymptomatic human volunteers and 210 patients that had a hip joint replacement for primary OA.

Species of the HAKF group had the smallest HNR (1.10, SD:0.09). Species of the Arboreal group had significantly higher HNR (1.63, SD:0.15) in comparison to the Bipedal group (1.41, SD:0.04) (p=0.006), Human (1.33, SD:0.08) and the OA group (1.3, SD:0.09).

The range of movement associated with arboreal habitat caused an associated change in HNR. This study would suggest that the HNR peaked in the Miocene period with species that ambulated on both ground and trees. More recent homonin gait appears to have developed a smaller HNR and humans have the smallest amongst their close ancestors. Evolutionary theory would suggest that modern environmental pressures might pre-dispose future hominin evolution to OA, secondary to a further reduction in HNR.

Full-thickness burns around the knee can involve the extensor mechanism. The gastrocnemius flap is well described for soft tissue reconstruction around the knee. We describe a method where a Whichita Fusion Nail¯ knee arthrodesis, combined with a medial gastrocnemius muscle flap was used to salvage the knee and preserve the lower leg following a full-thickness contact burn.

The gastrocnemius flap for wound coverage of an open knee joint was originally described in 1970 and remains the workhorse for soft tissue knee reconstruction. There are a number of local alternatives including the vastus lateralis, medialis and sartorius flap; and perforator flaps such as the medial sural artery perforator island flap and islanded posterior calf perforator flap, however many of these are unsuitable for larger defects.

Full-thickness burns around the knee can put the extensor mechanism at risk and subsequent rupture is a possible consequence. The gastrocnemius flap has been used to cover a medial knee defect with exposed joint cavity following a burn and also been used in post burn contracture release around the knee.

The primary indication for Wichita fusion nail is a failed total knee replacement. It allows intramedullary stabilization with compression at the arthrodesis site to stimulate bone union. With fusion rates reported up to 100% and low complication rates as compared to other methods of fusion, the technique has a useful role in limb salvage type procedures.

While use of the gastrocnemius flap in knee burns has been described before we believe this is the first time that this combination of techniques, namely knee arthrodesis with soft tissue reconstruction using a gastrocnemius flap, has been reported. Combining these procedures with a multidisciplinary approach provides a useful alternative leading to limb salvage and avoiding the need for an above knee amputation when extensor reconstruction is not possible.

Aim

A case series with functional and radiographic outcomes, of modular endoprosthetic distal femoral replacement in complex cases of periprosthetic fracture.

Introduction: The use of highly cross-linked polyethylene (HXLPE) is now commonplace for total hip arthroplasty, however there is no long-term data to support its use. Hip simulator studies suggest that the wear rate of some types of HXLPE is ten times less than conventional polyethylene (UHMWPE). The outcomes of hip simulator studies are not always reproduced in vivo and there is some evidence that HXLPE wear may increase between 5 and 7 years.

Method: A prospective double blind randomised control trial was conducted using Radiostereometric Analysis (RSA). Fifty-four subjects were randomised to receive hip replacements with either UHMWPE liners or HXLPE liners. All subjects received a cemented CPT stem and uncemented Trilogy acetabular component (Zimmer, Warsaw, IN, USA). The 3D penetration of the head into the socket was determined to a minimum of 7 years.

Results: The total liner penetration was significantly different at 7 years (p=0.005) with values of 0.33 mm (SE 0.05 mm) for the HXLPE group and 0.55 mm (SE 0.05 mm) for the UHMWPE group. The steady state wear rate from 1 year onwards was significantly lower for HXLPE (0.005 mm/yr, SE 0.007 mm/yr) than for UHMWPE (0.037 mm/yr, SE 0.009 mm/yr) (p=0.007). The direction of wear was supero-lateral.

Discussion: We have previously demonstrated that the penetration in the first year is creep-dominated, from one year onwards the majority of penetration is probably due to wear. This study confirms the predictions from hip simulator studies which suggest that the wear rate of this HXLPE approaches that of metal-on-metal and ceramic-on-ceramic articulations. HXLPE may have the potential to reduce the need of revision surgery, due to wear debris induced osteolysis. It may also enable surgeons to use larger couples, thus reducing the risk of impingement and dislocation.

Introduction: Although originally designed to aid the management of primary malignant bone tumours, the indications for modular endoprosthetic replacement (EPR) have expanded to include complex periprosthetic fractures and failed internal fixation. The objective of this study was to evaluate the success of endoprosthetic replacement (EPR) in patients who had undergone limb salvage following complex trauma presentations.

Materials and Methods: Between 2003 and 2008 twenty one patients presented with complex trauma related problems and underwent EPR at a specialist tertiary referral centre. The mean age was 71 years (range 44–87) and the median number of previous surgical procedures was 3 (range 0–11). Eight patients presented following failed internal fixation of proximal femoral fractures. Nine patients had periprosthetic fractures around joint arthroplasties, seven relating to total knee replacements (TKRs) and two to total hip replacements (THRs). One case of periprosthetic fracture around THR had undergone failed internal fixation. Two patients had distal femoral fractures, of which one was infected and had undergone failed internal fixation, while the other was unreconstruc-table. Two patients had proximal tibia fractures which had both undergone failed internal fixation.

Results: The mean Harris Hip Score was 89.5 (range 64–85) at a mean follow up period of 8 months (minimum 4 months). The mean American Knee Society Score was 82 (range 62–100) and the mean functional score was 62 (range 30–75) at a mean follow up period of 6 months (minimum 2 months). Complications included two cases of deep infection; one resulted in a two stage revision procedure, while the other retained the EPR following a washout.

Conclusion: Modular EPR in the lower limb is a durable reconstructive option in complex trauma problems, particularly in the elderly and those patients with significant bone loss. Preliminary functional results indicate very satisfactory results.

Although originally designed to aid the management of primary malignant bone tumours, the indications for modular endoprosthetic replacement (EPR) have expanded to include complex periprosthetic fractures and failed internal fixation. The incidence of these challenging cases is increasing with an aged population. We reviewed retrospectively our experience with the use of EPR in patients who had undergone limb salvage following complex trauma presentations.

Between 2003 and 2008 twenty one patients underwent EPR following referral to the Oxford Sarcoma Service following lower limb trauma. The average age was 71 years (44–87). The average number of previous surgical procedures was 3 (range 0–11).

The mean Harris Hip Score was 89.5 (range 64–85). The mean American Knee Society Score was 82 (range 62–100) and the mean functional score was 62 (range 30–75). Complications included two cases of deep infection; one resulted in a two stage revision procedure, while the other retained the EPR following a washout. EPR is an effective salvage procedure for failed trauma fixation and periprosthetic fractures. Immediate weight bearing and a good functional outcome can be expected in this difficult group of patients.

Introduction: Symptomatic abnormal soft-tissue masses relating to the hip joint, such as those described as pseudotumours, are being increasingly reported following metal-on-metal hip resurfacing arthroplasty (MoMHRA). These were found to be locally destructive, requiring revision surgery in a high proportion (75%) of patients. Lymphocyte infiltrations seen in pseudotumours were similar to aseptic lymphocyte vascular associated lesion (ALVAL), which is thought to represent a T-lymphocyte-mediated delayed type hypersensitivity. Therefore, a delayed hypersensitivity reaction to nickel (Ni), chromium (Cr) or cobalt (Co) has been suggested to play a role in pseudotumour aetiology. In patients with bilateral MoMHRA who presented with symptoms on one side, subsequent scans have demonstrated pseudotumours both on the symptomatic and asymptomatic side. Thus, there are concerns that there may be an appreciable number of asymptomatic pseudotumours that surgeons are unaware of and these may eventually become symptomatic.

Aim: The aims of this study were:

to determine the prevalence of asymptomatic pseudotumours after MoMHRA; and

Methods: A total of 201 MoMHRA implanted hips in 158 patients (97 male, 61 female) with a mean age of 56 years (range 33–73 years) were evaluated. The mean follow-up was 61 months (range 13–88 months). Resurfacing devices implanted included 128 Birmingham Hip Resurfacing, 66 Conserve Plus and seven ReCap. The control groups included additional 20 patients, 10 male and 10 female (a mean age 68 years, range 57–80 years) with metal-on-polyethylene total hip arthroplasty and a further 22 age-matched patients (a mean age 55 years) without any metal implants. Ultrasound was used as the initial imaging modality and MRI was used to assess the extent of the identified masses. Patients with a soft-tissue mass had ultrasound-guided aspiration or core biopsy performed. Venous blood samples were collected in all patients for serum cobalt and chromium ion levels analysis using Inductively-Coupled Plasma Mass Spectrometer and lymphocyte transformation tests (LTT). The Oxford Hip Score (OHS) was used to measure the functional outcomes of patients. Acetabular component abduction angle was measured from standardised anteroposterior pelvis radiographs.

Results: Prevalence – Pseudotumours were found in 7 patients (6 female and 1 male). The overall prevalence of asymptomatic pseudotumours was 4%, with a relatively very high (30%) prevalence in females with bilateral implants. Histological examinations showed extensive necrosis of connective tissue, in which there were scattered aggregates of metal particles and a diffuse lymphocyte infiltrate.

Metal Ion Levels – The presence of pseudotumour was associated with significantly higher median serum cobalt levels (9.2mg/L vs. 1.9mg/L, p< 0.001), chromium levels (12.0mg/L vs. 2.1mg/L, p< 0.001), hip aspirate cobalt levels (1182 mg/L vs. 86.2mg/L, p=0.003), and aspirate chromium levels (883mg/L vs. 114.8mg/ L, p=0.006), as well as with inferior functional scores (OHS 41 vs. 47 p< 0.001). There was no significant difference in acetabular cup inclination angle (p=0.51). Lymphocyte Reactivity: A higher incidence and level of enhanced lymphocyte reactivity to Ni (p=0.001), but not to Co or Cr (the principal elements in the CoCr alloy used in metal-on-metal hip resurfacing implants), was found in patients with MoMHRA compared to the patients without MoM implants. However, lymphocyte reactivity to Co, Cr and Ni did not significantly differ in patients with pseudotumours compared to those patients without pseudotumours.

Conclusion: The prevalence of asymptomatic pseudotumours in females was high, especially in females with bilateral MoMHRA implants (30%). The patients with ‘asymptomatic’ pseudotumours were in fact mildly symptomatic. Lymphocyte reactivity to Co, Cr and Ni did not differ in patients with pseudotumour compared to those patients without pseudotumours, suggesting that systemic hypersensitivity type IV reactions, mediated by lymphocyte reactivity to these metals, is not the dominant mechanism in pathogenesis of the soft tissue pseudotumours. Furthermore, pseudotumours were not detected in those patients who had normal levels of cobalt and chromium ions. This suggests that pseudotumours do not occur if MoM articulations are well functioning. Therefore, pseudotumours are likely to be a biological consequence of the large amount of metal debris generated in vivo due to excessive wear.

MRI was used to diagnose occult hip pathology in patients with a clinically suspected femoral neck fracture where no abnormality was detected on plain x-ray. All patients admitted into our unit with post traumatic hip pain, an inability to weight bear, and no abnormality found on a series of plain radiographs, underwent an MRI scan of the pelvis and affected hip to look for an occult femoral neck fracture.

The study included 102 consecutive patients who were prospectively studied over a 10 year period between 1997 and 2007. Four patients were excluded due to contraindications or an inability to tolerate having an MRI scan. Of the remaining 98 patients 81 had abnormalities detected (83%). 42 of these patients had evidence of a proximal femoral fracture. 23 patients underwent an operative procedure.

Eight incomplete intertrochanteric fractures were treated non-operatively with good results. One patient had a primary diagnosis of malignancy made on the basis of the MRI scan. One patient had a known primary malignancy but this was the first diagnosis of bony metastatic disease. Seventy five patients were scanned within 48 hours of admission (average 2.4 days).

The use of MRI in our unit was felt to be appropriate in patients with a high suspicion of proximal femoral fracture. Our results show that there is a significant incidence of fractures that are not apparent on plain x-rays. MRI led to early diagnosis and initiation of definitive management, potentially reducing cost and complications of immobility. It was most useful in showing the extent of the fracture, and picked up on other occult pathologies of the hip and pelvis. We recommend stabilisation of femoral neck fractures and non operative management of all incomplete intertrochanteric fractures if able to non weight bear. There must be a high index of suspicion of undiagnosed malignancy

Metal on Metal Hip Resurfacing Arthroplasty (MoMHRA) has gained popularity due to its perceived advantages of bone conservation and relative ease of revision to a conventional THR if it fails. Known MoMHRA-associated complications include femoral neck fracture, avascular necrosis/collapse of the femoral head/neck, aseptic loosening and soft tissue responses such as ALVAL and pseudotumours. This study’s aim was to assess the functional outcome of failed MoMHRA revised to THR and compare it with a matched cohort of primary THRs.

Method: We have revised 53 MoMHRA cases to THR; the reasons for revision were femoral neck fracture (Fracture Group, n=21), soft tissue reaction (Pseudotumour Group, n=16) and other causes (Other Group, n=16: loosening, AVN and infection). Average followup was 2.9 years. These MoMHRA revisions were compared with 103 matched controls from a primary THR cohort; matched for age, gender and length of followup. We compared, using the MannWhitney U test, operative time (OT, measured in minutes), and Oxford Hip Score (OHS) between the revised MoMHRA groups and their individual controls. We also compared, using the Kruskal Wallis test, UCLA Activity Score in the revised MoMHRA groups.

Results: There were no differences between the Fracture Group (mean OT 99.6, SD: 30.4; mean OHS 19.8, SD:9.2) and its controls (mean OT 95.9, SD: 31.8; mean OHS 17.3, SD: 7.5) nor between the Other Group (mean OT 129.4, SD: 36.7; mean OHS 22.2, SD: 9.4) and its controls (mean OT 104.4, SD: 39.2; mean OHS 20.3, SD: 10.1) in terms of OT and OHS. The Pseudotumour Group had significantly longer OT (mean 161.6, SD: 24.5, p< 0.001) and worse outcome (mean OHS 39.1, SD: 9.3, p< 0.001) than its controls (mean OT 113.1, SD: 51.7; mean OHS 20.0, SD: 9.2). In the Fracture Group, there were 3 infections requiring revisions. For the Pseudotumour Group, there were 3 recurrent dislocations, 1 femoral artery stenosis and 3 femoral nerve palsies. In the Other Group, there were 2 periprosthetic fractures. There was significant difference (p< 0.001) in UCLA scores between the MoMHRA groups. The Pseudotumour Group had the lowest mean UCLA score of 3.8 (SD: 1.89). The Fracture Group (mean: 7.0, S.D. 2.0) and the Other Group (mean: 6.7, S.D. 2.1) had similar UCLA scores.

Discussion: The results demonstrate that outcome after revision of MoMHRA is dependent upon the indication for revision. Patients revised for soft tissue reactions had significantly worse outcome. Patients with soft tissue reactions are more likely to experience complications and require further surgical intervention. The pseudotumour associated revisions were associated with a significantly prolonged OT. The overall complication rate for the study groups was quite high, with 11 (21%) revised MoMHRA cases experiencing a complication. The Pseudotumour Group had a higher complication rate (37%).

Patello-femoral instability (PFI) affects 40 individuals per 100,000 population and causes significant morbidity. The causes of patello-femoral instability are multi-factorial, and an isolated anatomical abnormality does not necessarily indicate instability. Patello-femoral subluxation ranges from 0% (stable patella tracking) to 100% (dislocation) and there is an established relationship between the amount of subluxation and anterior knee pain. Traditionally, magnetic resonance (MR) imaging and standard radiographs are used to guide the clinician towards a suitable corrective procedure for PFI. The multi-factorial nature of patello-femoral instability is not addressed with current imaging techniques. This study aims to address which anatomical variables assessed on MR images are most relevant to patello-femoral subluxation. This information will aid surgical decision making, particularly in selecting the most appropriate reconstructive surgery.

A retrospective analysis of MR studies of 60 patients with suspected patello-femoral instability was performed. All patients were graded for degree of subluxation using a dynamic MR scan.

The patient scans were assessed for the presence of a specific range of anatomical variables:

patella alta, (modified Insall-Salvatti)

The Wilk’s Lambda test for multi-variate analysis was used to establish whether any relationship was present between the degree of patello-femoral instability and bony or soft tissue anatomical variables. Non-parametric statistical tests were applied across the groups and within the groups to assess their relative significance.

The following variables showed a significant relationship with patellofemoral subluxation; distance of the VMO from the patella (< 0.001), TTD (< 0.001), patella engagement (0.001), sulcus angles (0.004) and patella alta (0.005).

This study agrees with previous work showing a significant correlation between subluxation and trochlea sulcus angle and TTD.

This is the first study to establish a significant correlation between patella engagement and radiological instability. The lower the percentage engagement of the patella in the trochlea, the greater the degree of patello-femoral instability. Patella engagement showed a more significant relationship with subluxation than patella alta.

We report a new method of predicting patello-femoral instability by measuring the overlap of the patella in the trochlea groove.

The purpose of the study was to establish an algorithm for the treatment of pathological fractures in children.

Pathological fractures can compromise radiographic and histological diagnosis. The need for histological diagnosis and indications for surgical treatment are not clearly defined.

We reviewed our Centre’s Tumour Registry records of children who presented over the past 7 years with a fracture as the first manifestation of primary bone pathology. There were 23 patients (average age 12 years and 2 months).

There were 9 fractures through simple bone cysts, all treated conservatively initially. All patients were subsequently treated with needle biopsy and bone marrow injection. Three patients suffered refracture and underwent flexible intramedullary nail fixation.

There were 5 cases of fibrous dysplasia. Histological diagnosis was obtained in all cases, followed by prophylactic intramedullary nailing in 3 patients.

There were 2 patients with giant cell tumour, 3 with aneurysmal bone cyst and one with chondroblastoma. Histological diagnosis preceded curettage and grafting in all cases.

Finally, there were 3 patients with Ewing’s sarcoma of the femur. One underwent palliative intramedullary nailing for extensive local disease. The second patient was treated conservatively initially. She subsequently underwent segmental resection and vascularised fibular graft. The third patient underwent internal fixation in another unit for what was considered to be a benign lesion. The histological diagnosis of Ewing’s sarcoma was based on intra-operative specimens. Definitive surgery required wide resection and prosthetic replacement.

We recommend that primary fixation of pathological fractures should be avoided until histological diagnosis is obtained. All lesions should be appropriately imaged and biopsied if aggressive characteristics are present. However, if radiographic appearances are reassuringly benign, biopsy can be delayed until conservative fracture management is completed. Definitive treatment of benign lesions with protective intramedullary nailing or curettage and grafting can follow frozen section under the same anaesthetic.

Giant cell tumour of bone (GCTB) is an expansile osteolytic tumour of bone which contains numerous osteoclast-like giant cells. GCTB is a locally aggressive tumour which can cause extensive bone destruction that can be difficult to control surgically, up to 35% of cases recurring after simple curettage. Bisphosphonates are anti-resorptive agents that have proved effective in the treatment of a number of osteolytic conditions.

In keeping with its known effect on osteoclasts, we found that the aminobisphosphonate zoledronate abolished in vitro lacunar resorption in cultures of osteoclasts isolated from GCTB. The effect of zoledronate and other bisphosphonates on 15 cases of recurrent primary GCTB, four of which had metastasised to the lung, was assessed clinically. Most recurrent tumours did not exhibit progressive enlargement and, in some cases, both primary and metastatic GCTBs showed a degree of radiological improvement following treatment However, tumours did not diminish in size and, in some cases, no apparent treatment effect was noted.

Our findings provide in vitro evidence for the use of bisphosphonates to inhibit the progressive osteolysis associated with GCTB. In vivo, these agents produced a degree of clinical and radiological improvement in some cases. This study reports results from three European centres where bisphosphonates are being used to treat recurrent GCTB and highlights the fact that these centres are all employing different clinical indications and different regimes of bisphosphonate treatment. Bisphosphonates have significant side effects and indications for treatment and standardisation of drug type and dosage regimes (and measurement of agreed outcome measures to determine treatment efficacy) should be established before these agents are included as part of a treatment protocol to control GCTB tumour growth and osteolysis.

The infrapatellar (Hoffa’s) fat pad can be affected by a variety of tumours and tumour-like conditions which can occasionally present a diagnostic and therapeutic challenge to the treating surgeon. The fat pad can be affected by diffuse or solitary disease. Solitary tumours are relatively uncommon but with widespread uptake of Magnetic Resonance Imaging Scans (MRI) an increasing number of Hoffa’s fat pad tumours (HFP) are being recognized.

Between 1999 and 2008, 20 patients with HFP pathology referred to Oxford bone and soft tissue tumour service underwent resection and histological examination. Clinical records, imaging and histological findings were reviewed. Histology showed eight different diagnoses with Pigmented Villonodular Synovitis (PVNS) and ganglia being the most common pathology.

In one patient, MRI identified the cause of hypophosphataemic osteomalacia as an HFP phosphaturic mesen-chyma tumour despite the lack of local symptoms.

In conclusion, the majority of solitary HFP tumours are benign and maybe cystic or solid. MRI and plain radiographs are the imaging of choice. Cystic tumours maybe aspirated but the definitive treatment of both cystic and solid tumours should be open arthrotomy and excision biopsy. Arthroscopic resection is not advised, as complete excision is not always possible. None of the 20 patients in this series had a malignant tumour but this has been reported in the literature. Calcification on plain radiographs may indicate a malignant lesion. All patients in our series reported substantial improvement in symptoms following open tumour resection.

Introduction: Despite the satisfactory short-term implant survivorship of MoM hip resurfacing arthroplasty, symptomatic abnormal periprosthetic soft-tissue masses relating to the hip joint, ‘pseudotumours’, are being increasingly reported. These were found be locally destructive, requiring revision surgery in 75% of patients. Asymptomatic pseudotumours have not been previously investigated.

Methods: The aims were: (1) to investigate the prevalence of asymptomatic pseudotumours; and (2) to investigate their potential association with the level of metal ions. A total of 160 hips in 123 patients with a mean age 56 years (range 33–73) were evaluated at a mean follow-up of 61 months (range 13–88). Radiographs and OHS were assessed. Patients with a cystic or solid mass detected on the ultrasound/MRI had an aspiration or biopsy performed. Cobalt and chromium levels were analysed using Inductively-Coupled Plasma Spectrometer.

Results: Pseudotumours were found in 6 patients (5F: 1M). In 80% of bilateral cases, it was found in both sides. Histological examination showed extensive necrosis and diffuse lymphocyte infiltration. The presence of pseudotumour was associated with higher serum cobalt (9.2 μg/L vs. 1.9μg/L, p< 0.001) and chromium levels (12.0μg/L vs. 2.1μg/L, p< 0.001); higher hip aspirate cobalt (1182 μg/L vs. 86.2μg/L, p=0.003) and chromium levels (883μg/L vs. 114.8μg/L, p=0.006); and with inferior OHS (23 vs. 14 p=0.08).

Discussion: The prevalence of asymptomatic pseudotumour (5%) was higher than previously reported for the symptomatic pseudotumours (1%). There was a sixfold elevation of serum and a twelve-fold elevation of hip aspirate levels of cobalt and chromium in patients with pseudotumours. This suggests that pseudotumours may be a biological consequence of the large amount of metal debris generated in vivo. The association between pseudotumour and elevated metal ion levels might theoretically be explained by either systemic hypersensitivity responses to metal ions or local cytotoxic effects due to a high level of metal ions.

Introduction: We report on a group of 20 metal-onmetal resurfaced hips (17 patients) presenting with a soft tissue mass associated with various symptoms; these masses we termed pseudotumours.

Methods: All patients underwent plane radiography; CT, MRI and ultrasound investigations were also performed for some patients. Where samples were available histology was performed. Metal ion levels were measured in six patients and one patient had the metal ion levels in the joint fluid measured.

Results: All patients in this series were female. Presentation was variable; the most common symptom was pain or discomfort in the hip region. Other symptoms included spontaneous dislocation, nerve palsy, a noticeable mass or a rash. In all cases a soft tissue mass was present in the region of the hip, this was either solid or cystic. The common histological features were extensive necrosis and lymphocytic infiltration. The blood cobalt and chromium levels varied considerably between the six patients that had these measurements. The median blood chromium level was 3.8 μg/L (range 0.8 to 23 μg/L) and that for cobalt was 11.5 μg/L (range 2.1 to 15 μg/L). The synovial fluid sample taken from a single joint contained much higher metal levels, 701 μg/L for chromium and 329 μg/L for cobalt. Twelve of the 20 cases have so far required revision to a conventional hip replacement.

Discussion: This complication is best imaged with ultrasound, and is not detected by normal xray. We estimate that about 1% of patients develop a pseudotumour in the first five postoperative years. The cause of these pseudotumours is unknown and is probably multifactorial, further work is required to define this; they may be manifestations of a metal sensitivity response. We are concerned that with time the incidence of these pseudo-tumours will increase.

Introduction: Osteoclast-like multinucleated giant cells (MNGCs) are found in a number of soft tissue sarcomas including malignant fibrous histiocytoma and leiomyosarcoma. The nature of these MNGCs is poorly understood and the cellular mechanisms underlying their accumulation in sarcomas is not known.

Methods: We analysed by immunohistochemistry the expression of osteoclast, macrophage and smooth muscle markers by mononuclear and multinucleated cells in two cases of giant cell-rich leiomyosarcoma. We also characterised the role of mononuclear stromal cells and tumour-associated macrophages in the formation of MNGCs by RT-PCR, cell culture studies and immunohistochemistry/histochemistry for macrophage, osteoclast and smooth muscle markers

Results: MNCGs in giant cell-rich leiomyosarcoma expressed an osteoclast-like phenotype, being negative for smooth muscle actin and CD14 but positive for tartrate-resistant acid phophatase (TRAP), CD45, CD68 and vitronectin receptor (VNR). Scattered mononuclear cells expressing an osteoclast-like antigenic phenotype were also noted. An analysis of 25 conventional (non-giant cell-containing) leiomyosarcomas found isolated CD68+ MNGCs in three cases (approximately 12%); all of these cases were Grade-II/III leiomyosarcomas in which there was a prominent tumour-associated macrophage (TAM) infiltrate. Leiomyosarcoma TAMs isolated from two cases of conventional leiomyosarcoma and cultured in the presence of the osteoclastogenic factors RANKL and M-CSF differentiated into TRAP+/VNR+ MNGCs that were capable of lacunar resorption. RT-PCR studies showed that cultured leiomyosarcoma mononuclear stromal cells expressed RANKL, OPG and TRAIL.

Discussion: These findings show that the MNGCs which are found in leiomyosarcomas are osteoclast-like in nature and that these MNGCs are formed from TAMs by a RANKL dependent mechanism which involves an interaction with RANKL-expressing mononuclear stromal cells. A similar mechanism is likely to account for MNGC accumulation in other soft tissue sarcomas.

Introduction: Young active patients with malignant tumours arising in the distal fibula, requiring bone and soft tissue excision, present a challenge to the treating surgeon. Wide local excision is advocated, to achieve clearance, however, disruption of the ankle mortise results and fusion is often required to restore stability. The loss of movement is poorly tolerated in the younger patient and leads to progressive degenerative changes in surrounding joints.

Method: Excision of the distal fibula lesion followed by rotation of the proximal fibula on its vascular pedicle recreates the ankle mortise with consequent restoration of ankle stability and retaining ankle movement.

Results: Between 2000 and 2008, we have performed this technique on four patients, (2F, 2M) mean age 21 (13–33). Diagnoses were that of chondrosarcoma, parosteal osteosarcoma, Ewings sarcoma and osteofibrodysplasia. Follow up at 5 years (18m-8 year) with no evidence of local or distant recurrence. One case was complicated by deep infection requiring surgical debridement and antibiotic therapy. In all cases the fibula grafts survived. Good to excellent functional results were achieved (Toronto Extremity Salvage Scores, mean 88 range 82–94).

Discussion: We will present the technical aspects of this procedure with particular reference to the most recent case, performed on a young female patient with parosteal osteosarcoma.

We believe this technique provides good oncological and functional results and recommend this treatment option is considered in young active patients required distal fibula excisions for sarcoma.

We report on a group of 20 metal-on-metal resurfaced hips (17 patients) presenting with a soft tissue mass associated with various symptoms. We describe these masses as pseudotumours.

All patients underwent plain radiography and fuller investigation with CT, MRI and ultrasound. Where samples were available, histology was performed. All patients in this series were female. Presentation was variable; the most common symptom was pain or discomfort in the hip region. Other symptoms included spontaneous dislocation, nerve palsy, an enlarging mass or a rash. The common histological features were extensive necrosis and lymphocytic infiltration. Fourteen of the 20 cases (70%) have so far required revision to a conventional hip replacement and their symptoms have either settled completely or improved substantially since the revision surgery. Two of the three bilateral cases have asymptomatic pseudotumours on the opposite side.

We estimate that about 1% of patients develop a pseudotumour in the first five postoperative years after a hip resurfacing. The cause of these pseudotumours is unknown and is probably multi-factorial, further work is required to define this; they may be manifestations of a metal sensitivity response. We are concerned that with time the incidence of these pseudotumours will increase.

Introduction: We report on a group of 20 metal-on-metal resurfaced hips (17 patients) presenting with a soft tissue mass associated with various symptoms; these masses we termed pseudotumours. All patients underwent plane radiography; CT, MRI and ultrasound investigations were also performed for some patients. Where samples were available histology was performed.

Methods: All patients in this series were female. Presentation was variable; the most common symptom was pain or discomfort in the hip region. Other symptoms included spontaneous dislocation, nerve palsy, a noticeable mass or a rash. The common histological features were extensive necrosis and lymphocytic infiltration. Fourteen of the 20 cases (70%) have so far required revision to a conventional hip replacement and their symptoms have either settled completely or improved substantially since the revision surgery. Two of the three bilateral cases have asymptomatic pseudotumours on the opposite side.

Conclusions: We estimate that about 1% of patients develop a pseudotumour in the first five postoperative years after a hip resurfacing. The cause of these pseudotumours is unknown and is probably multi-factorial, further work is required to define this; they may be manifestations of a metal sensitivity response. We are concerned that with time the incidence of these pseudotumours will increase.

Young active patients with malignant tumours arising in the distal fibula, requiring excision, present a challenge to the treating surgeon. Wide local excision is advocated, to achieve clearance, however, disruption of the ankle mortise results and fusion is often required to restore stability. The loss of movement is poorly tolerated in the younger patient and leads to progressive degenerative changes in surrounding joints.

Excision of the distal fibula lesion followed by harvesting of the proximal fibula and using this graft to recreate the ankle mortise restores ankle stability and retains ankle movement.

Between 1998 and 2007, we have performed this technique on 4 patients. Diagnoses were Ewing’s sarcoma, chondrosarcoma, parosteal osteosarcoma and osteofibrous dysplasia. To date there has been no evidence of distant or local recurrence. One case was complicated by infection, which resolved with radical debridement and antibiotics; the other three fibula grafts survived. Good to excellent results were achieved.

We will present the technical aspects of this procedure, with particular reference to the most recent case, performed on a young female patient with parosteal osteosarcoma.

We believe this technique provides good oncological and functional results and recommend this treatment option is considered in young active patients requiring distal fibula excisions for sarcoma.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

Proprioception protects joints against injurious movements and is critical for joint stability maintenance under dynamic conditions. Knee replacement effect on proprioception in general remains elusive. This study aimed to evaluate the changes in proprioceptive performance after knee replacement; comparing Total (TKA) to Unicompartmental Knee Arthroplasty (UKA).

Thirty-four patients with osteoarthritis were recruited; 15 patients underwent TKA using the AGC prosthesis and 19patients underwent UKA using the Oxford prosthesis. Both cruciate ligaments were preserved in the UKA group, while only the PCL was preserved in TKA patients. Patients’ age was similar in both groups.> Joint Position Sense (JPS) and postural sway were used as measures of proprioception. Both groups were assessed pre- and 6 months post-operatively in both limbs. JPS was measured as the error in actively and passively reproducing five randomly ordered knee flexion angles between 30 and 70°using an isokinetic dynamometer. Postural sway (area and path) was measured during single leg stance using a Balance Performance Monitor. Functional outcome was assessed using the Oxford Knee Score (OKS).

Pre-operatively, no differences in JPS or sway were found between limbs in either group. No differences existed between the two groups. Post-operatively, both groups had significant improvement of JPS in the operated limb (UKA mean4.64°, SD1.44° and TKA mean5.18°, SD1.35°). No changes in JPS were seen in the control side. A significant improvement (P< 0.0001) in sway area and path was found in the UKA group only in both limbs. No significant changes in sway occurred in either limb of TKA patients. The OKS improved from 21.4 to 35.5 for TKA patients and from 23.9 to 38for UKA patients.

Both UKA and TKA improve proprioception as assessed by JPS. However, UKA alone improves postural sway in both limbs. This may impart explain why UKA patients function better than TKA patients

Introduction: Knee joint arthroplasty (total or unicompartmental) is the standard operative treatment for osteoarthritis (OA). Survival rate is good for both types but functional outcome is different. The function of unicompartmental knee arthroplasty (UKA) is substantially better than that of total knee arthroplasty (TKA). As function can be strongly influenced by proprioceptive ability, it is possible that improved outcome seen in patients with UKA results from retaining proprioceptive function associated with the cruciate ligaments. This prospective longitudinal study aimed to evaluate the change in proprioceptive performance after knee replacement; comparing TKA to UKA.

Methods and Materials: Two groups of patients with OA as diagnosed clinically and by X-ray were recruited. Group 1 consisted of 15 patients (mean age 65.8 years range 57–72 years, 10 females and 5 males) listed for TKA with the AGC prosthesis (Biomet, UK). Group 2 consisted of 19 patients (mean age 65.5 years range 52–75 years; 9 females and 10 males) listed for UKA with the Oxford UKA (Biomet, UK) for medial compartment OA. The ACL and PCL were present and preserved in all patients in Group 2, while only the PCL was preserved in Group 1 patients. Joint Position Sense (JPS) and postural sway were used as measures of proprioception performance. Both groups were assessed pre-and 6 months post-operatively in both limbs. JPS was measured using a dynamometer (KinCom, Chatanooga Ltd) as the error in actively and passively reproducing five randomly ordered knee flexion angles (30°, 40°, 50°, 60° and 70°). Postural sway (area, path and velocity) was measured during single leg stance using a Balance Performance Monitor (SMS Medical) for 30 seconds interval. Functional outcome was assessed using the Oxford Knee Score (OKS).

Results: Pre-operatively, no differences in JPS or sway were found between limbs in either group. No differences existed between the two groups. Post-operatively, both groups had significant improvement of JPS in the operated limb only (Mean ± standard deviation for UKA 4.64±1.44° and for TKA 5.18±1.35°). No changes in JPS were seen in the control side. An improvement in sway was found in the UKA group only. UKA patients showed significant improvement in both sway area and path (p< .0001) for both limbs post-operatively. No significant post-operative changes in sway occurred in either limb of TKA patients. The OKS improved postoperatively in both groups, rising from 21.4 to 35.5 for TKA patients and from 23.9 to 38 for UKA patients.

Conclusion: Interestingly, joint position sense improved for both groups but did not seem to show any difference between UKA and TKA. Postural sway was influenced by joint replacement type. Ligament retention may contribute to improved global postural control seen after unicompartmental knee arthroplasty and may explain the higher level of function seen in these patients.

Aim: To describe the radiographic findings of soft tissue sarcoma.

Materials and Method: The retrospective review of 100 consecutive patients with a histological diagnosis of primary soft tissues sarcoma of the extremities.

Results: Fifty five patients had plain radiographs at initial presentation. This was mainly due to the fact that most patients were tertiary referrals or had other initial imaging. Histological diagnosis in these patients was: liposarcoma in 24 patients, leiomyosarcoma in 8, undifferentiated spindle cell sarcoma in 5, malignant schwannoma in 4, synovial sarcoma in 4, MFH in 2, fibrosarcoma in 2, haemangiopericytoma, epithelioid sarcoma, malignant GCT, melanoma and spindle cell histiocytoma in one. The upper limb was involved in 18 patients and the lower limb was involved in 37. Thirty-five (63.6%) patients had a visible soft tissue mass on plain film. Eleven had mineralisation within the soft tissue mass and seven had either bone involvement or periosteal response. Those with a distinct soft tissue mass and evidence of fat content on plain film were noted to be diagnosis of liposarcoma in 86.7% of the cases. Mineralization was noted in synovial sarcoma (2), liposarcoma (3), leiomyosarcoma (1), MFH (2) and poorly differentiated sarcomas (2).

Conclusion: The plain radiograph is useful in assessing soft tissue tumour and abnormality is seen in 2/3 of cases reviewed. Mineralization as a radiographic finding features in malignant sarcoma notably liposarcoma. With tumours demonstrating fat on plain film this can correlate with MRI and facilitate surgical treatment avoiding biopsy.

We are presenting the outcome of a young adult with extensive epithelioid hemangioendothelioma of the femur treated with wide excision and vascularised fibular graft.

An 18-year-old builder was referred with an aggressive primary bone tumor of the right femur. Initial staging showed no evidence of distant disease but tumor confined to a 26.5cm diaphyseal segment of the femoral shaft. The patient’s pre-operative Oxford knee score was 28 and the AKSS scores were 74 (observational) and 65 (functional). True cut open biopsy confirmed low grade angiosarcoma. The patient underwent a wide excision of the lesion through a lateral approach leaving a generous cuff of bone and muscle tissue around the tumor. Clear resection margins were assessed intraoperatively. Histologically, the tumor was found to be epithelioid hemangioendothelioma. The 29.5cm defect was filled with a vascularised bone graft of the ipsilateral fibula. The graft was secured with a 22-hole DCS bridging plate and screws at both ends. Intraoperative knee range of motion was from 0 to 125 degrees without recurvatum and graft movement.

The patient had an unremarkable recovery. At the latest follow-up, one year after his operation, the patient had made an excellent functional recovery with non-symptomatic full weight bearing and had also returned to his work as a builder. He demonstrated a knee range of motion of 0 to 115 with a slight genu varum. The patient’s post-operative Oxford knee score was 40 and the AKSS scores were 70 (observational) and 90 (functional). Radiographs showed excellent union at the distal aspect of the graft and a healing stress fracture of the fibula graft at the proximal aspect.

Vascularized fibular graft with plating is a safe reconstruction limb salvage option for defects of long bones after tumor resection.

Purpose: To assess the functional outcome of patients who pre-operatively, were known to have sciatic nerve tumour involvement and proceeded to have nerve-preserving planned marginal excision with epineurectomy.

Methods: We identified patients who had surgery between 1997 and 2004, for soft tissue sarcomas in the posterior thigh with known sciatic nerve involvement. During this period it was the practice of the senior authors (MG & HG) to apply a nerve-preserving epineurectomy approach as part of their planned marginal excision of these tumours.

The identified patients had their notes reviewed, and were contacted by post to complete a Toronto Extremity Severity Score (TESS) questionnaire to assess lower limb function in day-to-day life. Details of their presenting features, oncological work-up, surgical intervention and adjuvant therapy was established and correlated to the TESS score.

Conclusion: This study demonstrates that a careful epineurectomy can preserve sciatic nerve function and allow tumour excision with no increase in local recurrence rate. With good soft tissue cover it appears nerve function can be maintained, even in cases where adjuvant radiotherapy is indicated.

Aims: The purpose of this study is to determine the causes of failed medial Oxford unicompartmental knee arthroplasty (UKA) and assess the outcome after revision surgery.

Materials And Methods: From 1993 to 2003, sixty-nine Oxford UKA (58 patients) were revised to a total knee replacements (TKR) at this centre. The type of implant used at revision surgery, pre- and post-revision American Knee Society (AKS) and Tegner scores were analyzed retrospectively.

Results: The patient’s mean age at the time of UKA was 64.5 years (range: 50–79). The average pre-revision scores were as follows: AKS-Objective score was 41.2 (± 10.4), the AKS-functional score was 56.8 (±10.0) and the average Tegner score was 1.5 (±0.6). The mean follow-up period was 38.3 (range: 12–107) months. The common causes of failure were: lateral compartment osteoarthritis (34.0%), component loosening (30.4%) and early or late infection requiring two-stage revision surgery (14.3%). The majority were revised using a standard primary TKR implant and only six (9%) requiring augmentation stems. Patellar resurfacing was performed in 25% of cases. The mean polyethylene liner width of the revision TKR was 13.4mm (±3.7). The average post-revision scores were: AKS-Objective score 77.4 (±13.1), the AKS-functional AKS score 70 (±21.1) and the average Tegner score of 2.2 (±0.8). Three knees needed rerevision for infection of the revised implant.

Conclusions: Lateral compartment osteoarthritis was the commonest indication for revision surgery for a failed medial Oxford UKA. Revision of a UKA is technically easier and the results are superior to the published results of revision of a primary TKR. In more than 90% cases, no augmentation or stemmed implants were necessary.

Aim: To assess the functional outcomes for patients treated by limb salvage surgery for sarcomas of the upper limb and shoulder girdle.

Materials and methods: Patients who had undergone limb salvage surgery for upper limb sarcoma between 1997 and 2004 were entered into the study. The operation notes were used to obtain details of the surgery. Pathology reports were consulted to identify the type, grade and margins of the tumour. The Toronto Extremity Salvage Score (TESS) questionnaire was used to assess post-operative function, in a postal survey.

Results: A total of 62 patients were identified. Liposarcoma was most common histological diagnosis, and “low” the most common grade (27). Histologically clear margins were achieved in 28 (44%) cases, marginal in 2 (3%), incomplete in 13 (21%) and indeterminate in 20 (32%). 30% had received adjuvant radiotherapy with or without chemotherapy as indicated. A total of 48 (76%) had been treated with excision and primary closure, 7 (11%) with local flaps, and 4 (6%) with endoprostheses. 10 patients had died, and 1 was untraceable. 29 completed TESS questionnaires were returned; with an average follow-up of 33 months post-resection (range 4 to 83). 11 female (38%), 18 male (62%), with an average age at surgery of 55. The average TESS score was 77 +/−10 with a range of 18–100. For the different regions, forearm sarcomas had an average TESS of 81 +/−17, upper arm 76 +/−19 and shoulder 81 +/−14.

Discussion: Surgical excision of soft tissue tumours with limb salvage aims to balance morbidity and mortality. Upper limb amputation has greater morbidity than lower limb and thus the argument for limb salvage should be stronger. A limb-salvage procedure should be considered preferable to amputation provided oncological outcomes are not compromised, and the resulting functional outcome is worth the oncological risk. In this cohort, patients had good functional outcomes, as described by the TESS functional assessment score, with no evidence of compromised oncological outcome during the follow up period.

Introduction This study assesses the outcome of medial unicompartmental knee arthroplasty (UKA) using the Oxford prosthesis for end-stage focal spontaneous osteonecrosis of the knee (SONK, Ahlback grades III & IV).

Methods A total of 29 knees (27 patients) with SONK were assessed using the Oxford Knee Score. Twenty-six had osteonecrosis of the medial femoral condyle; 3 had osteonecrosis of the medial tibial plateau. This group was compared to a similar group who had undergone Oxford Medial UKA for primary osteoarthritis. Patients were matched for age, sex and time since operation.

Results Mean length of follow-up was 5.2 years (range 1–13 years). There were no implant failures in either group, but there was one death 9 months post-arthroplasty from unrelated causes in the group with osteonecrosis. The mean Oxford Knee Score (SD) in the group with osteonecrosis was 37.8 (7.6) and 40.0 (6.6) in the group with osteoarthritis. There was no significant difference between the two groups using Student’s t-test (p=0.29).

Interpretation Use of the Oxford Medial UKA for focal spontaneous osteonecrosis of the knee is reliable in the short to medium term, and gives similar results to when used for patients with primary osteoarthritis.

Between 1972 and 2002 74 patients were treated under the combined care of the orthopaedic oncology service and lymphoma clinic with primary bone lymphoma. We reviewed the seventeen cases affecting the upper limb (23%). Of the seventeen patients nine remain alive. Assessment of the patient’s clinical presentation, histopathological definition, treatment and function outcome was made. The nine survivors were assessed clinically and with the Oxford shoulder score and the Toronto extremity salvage score.

Average time from first presentation to diagnosis was 7 months. All seventeen were diagnosed as a B –cell non-Hodgkin’s lymphoma, fifteen cases were high grade and two cases were low grade. The scapula was involved in six, humerus eight and clavicle three cases. Seven patients sustained pathological fractures three of which were at presentation; of these two were treated surgically. Eight patients have subsequently died of their disease. Functional outcome in surviving patients after medical treatment was very good with average TESS score of 79% (52%–99%) and OSS of 27 (12–52).

The presentation of lymphoma of the shoulder girdle may mimic benign shoulder conditions and lead to a delay in radiological and histopathological diagnosis. Pathological fracture is a common presentation and complication of treatment, however these fractures have a high chance of healing with medical treatment alone. Although shoulder stiffness remains a problem following medical treatment, overall upper limb function is good. There is little evidence that these patients require surgery in the short to medium term.

Purpose: Bone destruction occurs due to the growth of primary malignant bone tumours (sarcomas) that are often not amendable to surgery. Bone resorption is carried out by osteoclasts which are formed from cells of the mononuclear phagocyte system. Primary malignant bone tumours contain tumour-associated macrophages (TAMs) in addition to neoplastic cells. The aim of the study was to determine the cellular and humoral conditions required for TAM-osteoclast differentiation and to assess the affect of an anti-osteolytic agent on osteoclastic bone resorption.

Methods: TAMs were isolated form bone and soft tissue sarcoma by collagenase digestion and cultured in the presence of RANKL and M-CSF on coverslips and dentine slices for up to 21 days. The extent of osteoclast formation and resorption was determined by expression of osteoclast markers (TRAP, VNR, cathepsin K) in cell cultures on coverslips and the extent of lacunar resorption in cell cultures on dentine slices.

Results: Osteoclast formation occurred only when RANKL and M-CSF were added to the TAM cultures. This resulted in the formation of numerous mononuclear multinucleated cells which were strongly TRAP, VNR and cathepsin K positive. In cell cultures on dentine slices, it was noted that these cells were capable of extensive lacunar resorption with formation of multiple large lacunar resorption pits. The addition of the bisphosphonate zoledronate to the cell cultures resulted in inhibition of osteoclast formation and complete absence of lacunar resorption.

Conclusion: These findings indicate that sarcoma-associated macrophages are capable of differentiating into osteoclasts and that both RANKL and M-CSF are required for this to occur. This process is likely to contribute to tumour osteolysis associated with the growth of sarcomas in bone. Further assessment of the use of inhibitors of osteoclast formation/resorption, is also indicated by our results.

Over a five year period 50 patients required combined orthoplastic care out of 987 patients presenting with bone and soft tissue tumours. Thirty men, mean age 51 years, had their treatment reviewed at a mean follow up of 23 months (3–54 months) post surgery. All surviving patients completed the Toronto Extremity Salvage Score.

There were 23 bone and 27 soft tissue sarcomas, 4 were Enneking stage I, 41 stage II and 5 stage III. All tumours were removed by wide resection to achieve microscopically clear margins in 49. 9 endoprostheses were inserted. Soft tissue reconstruction involved 9 local flaps, 13 distant flaps (mainly muscle) and 8 free flaps (including 3 composite osseous flaps). 20 patients received adjuvant radiotherapy and 14 patients received chemotherapy.

Two endoprosthetic replacements required surgery for infection, one distant lap and one free flap required further surgery (6%). The mean disease free interval was 29 months (2–49 months). There were 6 deaths and pulmonary metastases occurred in a further 8 patients. Within this study period there was one episode of local recurrence, but no local recurrence in the group that had radiotherapy. 77% of surviving patients completed the Toronto Extremity Salvage Score and good to excellent function was seen in most cases.

Combined orthoplastic approach facilitates limb sparing surgery and early adjuvant radiotherapy.

The aim of this study was to establish the ability of an invasive fibre-optic probe to measure intra-muscular pH, pCO₂, pO₂, HCO₃-⁻, ambient temperature, base excess and O₂ saturation. The secondary aim was to determine the effect of elevation of the limb on these parameters.

Fibre-optic probes were introduced into the anterior compartment muscle of the leg in five volunteers via 16G cannulae. After equilibration the limb was monitored for 11min with the volunteer supine on an examination couch. The limb was elevated to 22cm (Braun frame) and then 44cm for the same time. Subsequently the leg was returned to 22cm and supine. All volunteers followed this set protocol. Continuous recording of all indices was made throughout. Data was stored to a personal computer for analysis.

Similar trends were observed across all subjects for all parameters. The mean pO₂ when lying flat was 27mmHg (S.D.7.4). Elevation to 22cm increased muscle pO₂ to 33 mmHg (S.D. 5.8). Further elevation to 44 cm resulted in a reduction in muscle pO₂ to a level below that measured when supine. When the limb was returned to 22cm the pO2 trend reversed, the level improving. Returning to the supine position the pO₂ returned to the level seen at the start of monitoring.

This novel probe gives reproducible measures of pH, pCO₂, pO₂, HCO₃⁻, ambient temperature, base excess and O₂ saturation. Results indicate that elevation to 22cm improves muscle oxygenation; a height of 44cm seems detrimental. This technique may be applicable in surveillance for compartment syndromes and muscle ischaemia.

Giant Cell Tumour of the Tendon Sheath is a benign tumour of synovial origin most frequently affecting the upper limb. Up to 11% exhibit radiographic evidence of cortical erosion and intra-osseous expansion. In the upper limb recurrence rates of between 10–50% following excision have been reported. However, GCT-TS is rarely described in the foot and ankle and its behaviour is ill understood.

17 cases of this rarely described tumour in the foot and ankle are presented, describing their clinical presentation, histopathology, treatment and outcome.

Analysis of all cases of histopathologically proven GCT-TS of the foot and ankle from the Oxford Tumour Registry, was conducted between the periods of January 1984 to December 1999.

22 cases were identified of which 17 cases had adequate records to allow analysis of patient demographics, duration of symptoms, preoperative investigations, presumed diagnosis, precise site of origin, post operative complications and recurrence rates

The mean age of presentation was 28 (8–53). 10 cases were female and 7 male. 76% cases occurred in the foot, all of which arose adjacent to the phalanges or heads of the metatarsals. 14% occurred in relation to the ankle or sub-talar joint.

82% presented with a painless swelling. The duration of symptoms ranged from 6 months to 8 years. Only one patient complained of sensory symptoms.

Pre-operative investigations included radiographs in 64% with 3 cases having an additional MRI scan. The MRI scans of GCT-TS have characteristic changes on T1 and T2 images. The presumed preoperative diagnosis was incorrect in 82%.

36% of radiographs taken showed changes including cortical erosion and speckled calcification.

A local excision was performed in 15 cases, an amputation in one and a wide local excision in one case only. There have been no recurrences during the follow up period of between 1–12 years.

GCT-TS of foot and ankle is rare and is commonly misdiagnosed. Despite only a local excision being performed in more than 80% of this series there were no recurrences.

Plain radiographs may show cortical erosion or speckled calcification in up to 36% and MRI is helpful in further defining the anatomy of the lesion, allowing planned excision and reducing the risk of recurrence.

Aim of study: To determine the long term outcome and complications associated with arthroscopic synovectomy in 22 knees with rheumatoid arthritis.

Methods: A consecutive series of 22 knees in 18 patients with seropositive RA underwent arthroscopic synovectomy for painful and swollen knees unresponsive to medical treatment. All operations were performed by the senior author. The mean age at operation was 44 years(22–64). All pre-operative Xrays showed Larsen grade 2 or less and no knees demonstrated marked joint laxity. Knee Society scores were recorded pre-operatively and at review, with a mean follow-up of 8 years (6–16).

Results: Two out of 22 knees(9%) have undergone TKR at 1 and 2 years post synovectomy. One patient underwent a further synovectomy for persistent swelling at 2 years and has since remained well. No per-operative complications were recorded but one large haemarthrosis and one stiff knee requiring manipulation were seen. The mean clinical and function scores increased by 22 and 15 points respectively at follow-up. The mean length of stay was 3 days and Xrays of the 20 knees not undergoing prosthetic replacement have all shown a small progression of degenerative radiological change.

Conclusion: This long-term study shows that arthroscopic synovectomy in appropriately selected patients with RA is a safe and reliable procedure with a low complication rate. The surgery is technically demanding but involves a shorter in-patient stay than with open synovectomy. The development of radiological degenerative changes were seen with all patients at review.

We analysed the histological findings in 1146 osteoarthritic femoral heads which would have been considered suitable for bone-bank donation to determine whether pathological lesions, other than osteoarthritis, were present. We found that 91 femoral heads (8%) showed evidence of disease. The most common conditions noted were chondrocalcinosis (63 cases), avascular necrosis (13), osteomas (6) and malignant tumours (one case of low-grade chondrosarcoma and two of well-differentiated lymphocytic lymphoma). There were two with metabolic bone disease (Paget’s disease and hyperparathyroid bone disease) and four with inflammatory (rheumatoid-like) arthritis. Our findings indicate that occult pathological conditions are common and it is recommended that histological examination of this regularly used source of bone allograft should be included as part of the screening protocol for bone-bank collection.

Aim: To test the hypothesis that open surgical synovectomy of the knee results in better long-term control of chronic inflammatory synovitis of the knee than arthroscopic synovectomy.

Method: To test this hypothesis a prospective clinical trial was carried out involving three groups of patients:- In Group I (22 cases in 18 patients) arthroscopic synovectomy was performed by a surgeon experienced in arthroscopy (Bartlett). In Group II (15 cases in 11 patients) open surgical synovectomy / debridement was performed (Rush). In Group III (10 cases in seven patients) arthroscopic lavage was carried without synovectomy (Rush) and this acted as a “control” group. The patients were followed up for some 10 years. At the final review the clinical and functional scores were recorded using the H.S.S. knee score system. There are obvious problems in comparing two or three groups of patients from two separate units and these are discussed.

Results: The results showed that in both groups (i.e. Groups I & II) there was a significant shift to the right in the clinical and functional scores. This did not occur in the “control” group. In Group I, two cases out of 22 came to total knee replacement. In Group II, four cases out of 15 and in Group III, five cases out of 10 came to knee replacement.

Conclusions: It was concluded that knee synovectomy was a worthwhile procedure and that arthroscopic synovectomy was just as good and probably better than open surgical synovectomy but it needs to be done early and by a surgeon with experience in carrying out this difficult procedure.

Of 1197 renal transplant recipients on the Oxford Transplant Programme, 25 (2%) needed arthroplasties for painful osteonecrosis of the hip. Nine of them had bilateral operations, giving a total of 34 primary total hip replacements (THR). The mean time from onset of symptoms to THR was 2.4 years and from transplantation to THR 5.1 years. The mean follow-up was 5.1 (1 to 14) years. THR relieved the pain in all the patients, but survival analysis indicated a lower survival rate than is usual for primary THR. There were eight major complications. One graft-related problem, early acute tubular necrosis, resolved rapidly after immediate treatment. One patient developed deep infection at 3.5 years after THR which settled with conservative treatment. Five hips developed aseptic loosening requiring revision arthroplasty at a mean of 8.8 years' follow-up. One patient had a non-fatal pulmonary embolism. THR is the treatment of choice for patients with painful osteonecrosis of the hip after renal transplant, but has higher rates of both early and late complications. Surgery should be performed in close association with a renal transplant unit.