The proximally hydroxyapatite coated neck retaining Freeman hip stem (Finsbury Orthopaedics, Leather-head, United Kingdom.) was first implanted in 1989. The outcome of the first 100 stems, in 52 men (6 bilateral) and 40 women (2 bilateral) has been reported to ten years, we have extended the follow-up of this series to 17 years.

The mean age was 58.9 years (19 to 84). The diagnosis was osteoarthritis for 70 hips, rheumatoid arthritis for seven hips, post-traumatic arthritis for 14 hips and either avascular necrosis, septic arthritis or developmental hip disorder in nine hips.

The total hip replacements implanted during the period of study (January 1989 to March 1992) were all secured without cement for either component. The acetabular components comprised press-fitted screw-in Rotalok implants (Corin Medical, Cirencester, United Kingdom) or SLF components (Finsbury). All operations were performed using an anterolateral approach with retention of the femoral neck. Three patients have been lost to follow-up, but are included up to their last clinical follow-up.

There have been 40 re-operations for revision of the acetabular component due to aseptic loosening. However, in all but four of these cases the stem was not revised. In two of these the stem revisions were for damage to the trunion following fracture of the modular ceramic head producing fretting against the ceramic debris and acetabular component. In the other two, revision was due to surgeon preference and in both cases well fixed femoral components were extracted at the time of acetabular revision. Osteointegration of these two stems was evidenced by the adherent bone at the time of removal. There has been only one case of aseptic loosening occurring at 14 years. This was found to be rotationally loose at revision and in hindsight was undersized having migrated distally 7.6mm in the first year before stabilising. The survivorship for the stem at 17 years is 98.5% (95% CI; 94.6% to 100%) with 52 patients at risk, all of whom have satisfactory clinical and radiological outcomes. The Freeman uncemented neck retaining proximally hydroxyapatite coated stem has excellent survival results to 17 years.

The outcome at ten years of 100 Freeman hip stems (Finsbury Orthopaedics, Leatherhead, United Kingdom) retaining the neck with a proximal hydroxyapatite coating in a series of 52 men (six bilateral) and 40 women (two bilateral), has been described previously. None required revision for aseptic loosening. We have extended the follow-up to 20 years with a minimum of 17 years. The mean age of the patients at total hip replacement was 58.9 years (19 to 84).

Six patients were lost to follow-up, but were included up to their last clinical review. A total of 22 patients (22 hips) had died, all from causes unrelated to their surgery. There have been 43 re-operations for failure of the acetabular component. However, in 38 of these the stem was not revised since it remained stable and there was no associated osteolysis. Two of the revisions were for damage to the trunnion after fracture of a modular ceramic head, and in another two, removal of the femoral component was because of the preference of the surgeon. In all cases the femoral component was well fixed, but could be extracted at the time of acetabular revision. In one case both components were revised for deep infection. There has been one case of aseptic loosening of the stem which occurred at 14 years. This stem had migrated distally by 7.6 mm in ten years and 8.4 mm at the time of revision at which stage it was found to be rotationally loose. With hindsight this component had been undersized at implantation.

The survivorship for the stem at 17 years with aseptic loosening as the endpoint was 98.6% (95% confidence interval 95.9 to 100) when 62 hips were at risk. All remaining stems had a satisfactory clinical and radiological outcome. The Freeman proximally hydroxyapatite-coated femoral component is therefore a dependable implant and its continued use can be recommended.

We describe the survivorship of the Medial Rotation total knee replacement (TKR) at ten years in 228 cemented primary replacements implanted between October 1994 and October 2006, with their clinical and radiological outcome. This implant has a highly congruent medial compartment, with the femoral component represented by a portion of a sphere which articulates with a matched concave surface on the medial side of the tibial insert.

There were 78 men (17 bilateral TKRs) and 111 women (22 bilateral TKRs) with a mean age of 67.9 years (28 to 90). All the patients were assessed clinically and radiologically using the American Knee Society scoring systems. The mean follow-up was for six years (1 to 13) with only two patients lost to follow-up and 34 dying during the period of study, one of whom had required revision for infection.

There were 11 revisions performed in total, three for aseptic loosening, six for infection, one for a periprosthetic fracture and one for a painful but well-fixed replacement performed at another centre.

With revision for any cause as the endpoint, the survival at ten years was 94.5% (95% CI 85.1 to 100), and with aseptic loosening as the endpoint 98.4% (95% CI 93 to 100). The mean American Knee Society score improved from 47.6 (0 to 88) to 72.2 (26 to 100) and for function from 45.1 (0 to 100) to 93.1 (45 to 100). Radiological review failed to detect migration in any of the surviving knees.

The clinical and radiological results of the Medial Rotation TKR are satisfactory at ten years. The increased congruence of the medial compartment has not led to an increased rate of loosening and continued use can be supported.

Purpose: Evaluation of a hands free crutch. This interesting device is intended for patients who have undergone foot and ankle surgery and should be non-weight bearing. It involves a knee tray attached to a vertical beam with a rubber foot. The crutch is strapped to the lower limb and weight is transferred though the proximal tibia.

Methods: Five Volunteers were assessed using the crutch, the K9 walker and 2 standard crutches in a simulated environment.

A comparison was made between this device and the K9 walker which has been shown to be a liberating walking aid indoors. Tasks from activities of daily living, productivity and transfers were included. Assessment was undertaken by the Occupational Therapy Team.

The hands free crutch was also compared with non weight bearing using two crutches to gauge performance outdoors. Assessment of ease of use and safety was undertaken by the Physiotherapy Team.

Results: Domestic chores including cleaning, cooking and shopping were possible using this device. Sitting activities were noted to be more difficult, because of the necessity to remove the crutch on each occasion.

Although speed was significantly greater (p< 0.0001.) using two crutches, the hands free crutch permitted safe outdoor mobilisation on even or uneven ground, up and down slopes with a gradient of 1 in 10 and up and down stairs. Good single leg stance stability was predictive of ease of use and safety for the hands free crutch.

Discussion: The hands free crutch is suited to motivated and physically able patients. Other lower limb pathology contraindicates the use of this device, but in patients with upper limb pathology it would permit non-weight bearing mobilisation. Good balance is paramount and perhaps a falls risk assessment should be performed prior to use.

Endoprosthetic reconstruction as a form of limb salvage in the management of malignant disease is common. We present our experience with custom-made distal femoral replacement as a form of limb salvage in the absence of malignancy.

49 cases of distal femoral replacement were identified using the unit database. There were 18 males and 31 females, with a mean age at operation of 62.3 years (range 26–86). There were 29 cases of failed total knee replacements, 8 cases of fracture associated with bone loss, non-union or deformity, 7 periprosthetic fractures, 3 aneurysmal bone cysts, and one case each of avascular necrosis and Gorham’s disease. Clinical and radiographic review of all available patients, including a functional assessment with the Musculoskeletal Tumour Society (MSTS) Score and Toronto Extremity Salvage (TES) score was undertaken.

The average follow-up was 5.4 years (range 1 to 29 years). Three types of endoprosthesis were used, rotating hinge, fixed hinge and arthrodesis prosthesis. One patient required amputation at 2 months following post-operative wound infection with methicillin-resistant staphylococcus aureus and subsequent inability to provide adequate soft tissue coverage. There was one revision at 16 months for deep prosthetic infection. 21 patients were available for functional follow-up. The mean MSTS score was 63.7 (range 16.0–86.7) and the mean TES score was 59.4 (range 9.4–87.5).

Custom-made distal femoral replacements have an established role in limb-salvage surgery for malignant disease. This series demonstrates the reconstructive capability of custom prostheses in non-malignant disease, where deformity causes functional embarrassment or when massive bone loss would normally lead to amputation.

Acute urinary retention (AUR) is a common complication following arthroplasty of the major joints and may lead to a delayed discharge with financial considerations not to mention the risks of sepsis – in the urinary tract and also rarely but very significantly in the joint itself. Our aim was to study the various factors associated with risk of AUR following arthroplasty.

We conducted a retrospective review of all available casenotes of patients undergoing total hip (THR) and knee arthroplasty (TKR) in a consecutive three year period. Variables noted included rate of AUR, catheterisation, urinary tract infection (UTI), urinanalysis, joint sepsis, anaesthetic type, use of patient controlled analgesia, postoperative morphine requirement, alpha blockade, past medical and urological history.

100 patients underwent THR. AUR occurred in 22%. Deep joint sepsis occurred in 1% – this patient had not been catheterised. 3% had positive urine analysis but were asymptomatic. No patients had a symptomatic postoperative UTI. 117 patients underwent TKR. AUR occurred in 19%. The rate of deep joint sepsis was 0.85%. There was one case of superficial infection. Neither of these cases was catheterised. There were no cases of postoperative UTI. There was correlation between previous AUR and incidence of AUR (p=0.95).

There was no significant correlation between past medical history and AUR contrary to reports by previous authors. The correlation between previous AUR with risk of AUR in the TKR group warrants further investigation. Catheterisation has been previously thought to be associated with infection. In our study with cefuroxime at induction and two doses postoperatively and gentamicin for catheter insertion and removal there were no cases of postoperative UTI and although deep sepsis was seen it was not associated with catheterisation either pre-operatively, perioperatively or postoperatively in AUR.

Midline skin incision and medial arthrotomy for knee arthroplasty may be preformed in flexion or extension. Anatomical studies have revealed a risk to the infra patellar branch of the saphenous nerve. This study addresses

whether sensory loss is greater following skin incision in flexion or extension.

Null hypothesis- there is no detectable difference in sensation before and after knee arthroplasty. Pilot study- light touch, sharp touch and two point discrimination were evaluated pre-operatively, at one week, six weeks and six months postoperatively in twelve patients recruited prospectively. Randomization was achieved using an envelope system. Six patients underwent approach and closure in flexion and six in extension. Prospective cohort study – 50 patients underwent sensory mapping for light touch and sharp touch pre-operatively. These control results were compared with the post-operative findings at six months. All measurements were standardised to anatomical landmarks with the knee in 90 degrees flexion.

There is a constant area of sensory loss lateral to the midline scar, which shows some recovery with time. The sensory loss affects both light and sharp touch. Initially, this is in a similar distribution anteriorly and laterally extending from the superior pole of the patella to the tibial tubercle, approximately 2cm lateral to the midline. The loss is most marked immediately after surgery. There is a noticeable recovery in sharp touch by six weeks. The recovery in light touch is slower and less complete at the six month review. There is no demonstratable difference in sensory loss regardless of whether the incision is made in flexion or extension, (p=0.1)

Lateral sensory loss is a constant feature in this series six months following knee arthroplasty. Patients may benefit from pre-operative counselling regarding the likelihood of lateral cutaneous sensory deficit following knee arthroplasty.

We describe a case of sciatic endometriosis in a 25-year-old woman diagnosed by MRI and histology with no evidence of intrapelvic disease.

The presentation, diagnosis and management of this rare condition are described. Early diagnosis and treatment are important to prevent irreversible damage to the sciatic nerve.

Introduction: Surgeons in the UK and Europe generally use a thinner cement mantle than their counterparts in the USA for the femoral component in total hip replacement (THR). The aim of this study was to compare the performance of different thicknesses of cement mantle using finite element analysis. The measures by which comparison might be made include cement cracking, subsidence, migration and stress shielding. In this study, we use a linear-elastic model of the implanted femur to give a prediction of the stresses in the cement mantle and in the femoral cortex. These measures give an indication of the relative rates of cement cracking and loss of bone stock due to stress shielding. To assess the reliability of our model in representing patients with different bone densities, we use a range of cancellous bone stiffnesses.

Method: Two cadaveric femora from the same donor were sized, reamed and implanted with identical plastic replica femoral components following standard surgical technique for the Stanmore Hip system. One was prepared using UK rasps, over-reaming by ~2mm, the other using US rasps, over-reaming by ~5mm. Serial CT-scans were used to create three-dimensional geometric models of the implanted femora. Two finite element meshes were hand-built in MSC. Marc finite element software, incorporating cortical and cancellous bone, bone cement and prosthesis. Each model consisted of 10,000 eight-noded brick elements, with a fully bonded stem-cement interface. The thick and thin cement mantles had thicknesses of 2.5mm and 1.0mm respectively, in regions where thickness is affected by rasp size. Models were identical in the distal medullary canal. Cortical bone was modelled as transversely isotropic, with longitudinal and transverse moduli of 17.0 and 11.5 GPa. Bone cement was given a modulus of 2.7 GPa. Loading conditions were chosen to represent the heel-strike phase of gait. In order to assess the impact of variability in patient bone density, cancellous bone modulus was varied between 0.06 and 2.90 GPa.

Results: Equivalent stress was examined on the external surface of the cortex and the internal surface of the cement mantle. The lowest cortical bone stresses were proximal and the highest cement stresses around the distal tip of the prosthesis. In the proximal cortex, higher equivalent stresses were observed medially and laterally with a thick cement mantle. Distally, lower cement stresses were observed in the thick cement mantle. With the highest cancellous modulus, there was little difference between the two models. As this modulus was reduced, stress differences between the models became more apparent. For all cancellous bone moduli, peak distal cement stresses were lower and minimum proximal calcar stresses higher in the thick cement mantle.

Discussion: Proximal stress shielding was greatest in the calcar, in agreement with clinical findings. The thicker cement mantle led to less stress shielding in this region. Cement stresses, highest around the distal tip of the prosthesis, were larger in the thin cement mantle. This suggests a higher rate of both cracking and bone resorption in thin cement mantles. Although observed over a range of cancellous bone stiffness, this finding applies particularly to patients with low bone density.

Introduction: Aseptic loosening remains the commonest causes of failure of total hip arthroplasty. Cement mantle defects are associated with aseptic loosening. This study aimed to determine a correlation between surgical approach and cement mantle defects in the Stanmore Hip. The Stanmore total hip replacement was chosen because it has greater than an eighty-five percent survivorship over 25 years and unlike other prostheses with comparable results such as the Charnley total hip, it remains essentially unchanged to date.

Method: This was a retrospective review of all Stanmore hips. AP and lateral radiographs were available for 62 patients operated via the posterior approach and 100 patients operated via the anterolateral approach. The mean cement thickness in all fourteen Gruen zones was estimated for each patient. Gruen zones IV and XI, representing the stem tip, were removed from data relating to mantle thickness. Mantles were graded as less than 2mm, 2–5mm, 5–10mm and more than 10mm. Alignment was also measured.

Results: Fifty-nine percent (32/54) of cement mantle defects are seen in Gruen zones VIII to XIV. The mean cement mantle thickness in A-L approach was 3.11mm compared to 4.23mm with the posterior approach. This corresponds with the frequency of cement mantle defects occurrence. No cement defects were seen in Gruen zones IV or XI. Using the anterolateral approach, defects were observed in 49 out of 1200 zones (4.08%) and using the posterior approach in 6 out of 744 zones (0.81%). With the anterolateral approach, 19 out of 100 cement mantles (19%) had defects, compared to only 3 out of 62 (4.84%) with the posterior approach. Defects were most commonly seen in zones I, V, VIII and XII, which corresponds to valgus and posterior orientation of the stem.

Discussion: The posterior approach does generate a more uniform cement mantle. Several studies suggest that a cement mantle smaller than 2mm or greater than 10mm can be detrimental to the survivorship of the arthroplasty. This study suggests that a deficient cement mantle is more likely using an anterolateral approach.

Introduction: Surgeons in the UK and Europe generally use a thinner cement mantle than their counterparts in the USA for the femoral component in total hip replacement. The aim of this study was to compare the performance of different thicknesses of cement mantle using finite element analysis. A linear-elastic model of the implanted femur is used to give a prediction of the stresses in the cement mantle and in the femoral cortex. These measures give an indication of cement cracking rates and stress shielding. To assess the reliability of our model in representing patients with different bone densities, we use a range of cancellous bone stiffnesses.

Method: Two cadaveric femora from the same donor were sized, reamed and implanted with identical Stanmore Hips. One was prepared using UK rasps, over-reaming by 2mm, the other using US rasps, over-reaming by 5mm. Serial CT-scans were used to create three-dimensional geometric models of the implanted femora. Two finite element meshes were hand-built in MSC.Marc finite element software, incorporating cortical and cancellous bone, bone cement and prosthesis, with a bonded stem-cement interface. Loading conditions were chosen to represent the heel-strike phase of gait. In order to assess the impact of variability in patient bone density, cancellous bone modulus was varied between 0.06 and 2.90 GPa.

Results: Equivalent stress was examined on the external surface of the cortex and the internal surface of the cement mantle. The lowest cortical bone stresses were proximal and the highest cement stresses around the distal tip of the prosthesis. In the proximal cortex, higher equivalent stresses were observed medially and laterally with a thick cement mantle. Distally, lower cement stresses were observed in the thick cement mantle. With the highest cancellous modulus, there was little difference between the two models. As this modulus was reduced, stress differences between the models became more apparent.

Discussion: Proximal stress shielding was greatest in the calcar, in agreement with clinical findings. The thicker cement mantle led to less stress shielding in this region. Cement stresses, highest around the distal tip of the prosthesis, were larger in the thin cement mantle. This suggests a higher rate of both cracking and bone resorption with thin cement mantles, particularly in patients with low bone density.

Purpose: To determine the mode of presentation of soft tissue sarcomas to a tertiary centre and the factors associated with a delay in diagnosis and referral.

Methods and Results Between 2000 and 2002, we identified 120 patients with primary soft tissue sarcomas histologically verified at our institution. We reviewed the case histories, referral letters and the histology reports in all cases. The mean age of the study group was 54.5 (range 10 to 91 years). Pathological diagnoses included 32 liposarcomas, 20 malignant fibrous histiocytomas, 19 synovial sarcomas, 12 leiomyosarcomas, 9 fibrosarcomas, 7 spindle cell sarcomas, 4 pleomorphic sarcomas, 3 identified only as high grade soft tissue sarcomas, 3 epithelioid sarcomas, 2 extraosseous Ewing’s sarcomas, 2 malignant round cell tumours and one each of neurofibroma, malignant peripheral nerve sheath tumour, angiosarcoma, alveolar cell sarcoma, extraosseous chondrosarcoma, extraosseous osteosarcoma and clear cell sarcoma of tendon sheath.

Presenting features included a discrete lump or diffuse swelling in 115 patients (95.8%). Pain was not a feature in 69 patients. 3 patients (2.5%) presented with pain alone and 2 patients (1.7%) with varicosities. 116 patients (96.7%) were referred to our unit as a possible soft tissue sarcoma. 4 patients were referred as suspected benign lesions requiring specialist assessment owing to size and location. 46 patients (38.3%) ignored their swelling, resulting in a delay to presentation to their local units. In only 13 patients was pain a feature. These were not considered to be true delayed referrals. 24 patients (20%) experienced a delayed referral to our unit. An alternative diagnosis was suggested in 7 patients by preliminary imaging investigations. A ‘Whoops procedure’ was performed in 14 patients. 3 patients were initially misdiagnosed as muscular injuries, with consequent conservative management resulting in delay.

Conclusion: Soft tissue sarcomas are relatively rare when considered alongside benign soft-tissue lesions. Pain is an infrequent feature, which may result in patients undervaluing their significance and delay their initial presentation to a doctor. Delayed referral is relatively common, although may not always be avoidable. Clinicians should maintain a high level of suspicion when dealing with soft-tissue lesions, with referral to a specialist centre whenever concern exists as to the nature of the lesion.

Purpose: Dedifferentiated chordomas are a rare and aggressive variant of chordoma. They usually occur in recurrences or following radiotherapy. We describe the rare occurrence of three cases arising de novo within conventional chordoma.

Methods and Results: 29 cases of histopathologically verified chordoma were identified from our unit database. From these, we identified three cases of primary dedifferentiated chordoma. The study group included three men, with an average age of 58.3 years (range 57–61). Presenting features were comparable and included lower back pain and rectal discomfort, with a mass palpable per rectum. A needle biopsy was undertaken in one patient, which demonstrated evidence of a pleomorphic spindle cell tumour without evidence of chordoma. Surgical management involved subtotal sacrectomy, with complete excision achieved in two cases. Histopathological examination confirmed dedifferentiated chordoma with varying amounts of sarcomatous elements in each case. Post-operative radiotherapy was administered in two patients and chemotherapy in one patient. Two patients died at 7 and 10 months following presentation with pulmonary metastases. The third patient remains well and alive at two years follow-up. This patient had a complete excision with post-operative radiotherapy, however histopathological examination revealed only a small focus of the dedifferentiated component.

Conclusions: Dedifferentiated chordoma is a fatal tumour, with metastases and death the likely outcome. Most cases in the literature and the two cases reported in this series, uphold this ominous prognosis. However this may not always hold true. Small areas of dedifferentiation within the chordoma tumour may carry a more favourable prognosis.

Myoneural blockade is a well-established means of reducing tone in spastic muscles, thereby delaying or avoiding the need for operative intervention. The recent interest in botulinum A toxin has tended to obscure the fact that other agents such as alcohol have been used for many years to achieve a similar effect.

Eighty-two children between the ages of 2 and 16 years with cerebral palsy underwent myoneural blocks using 45% ethanol for dynamic contracture of the hamstrings and/or gastrocnemius. The injections were performed under a light general anaesthetic, using a nerve stimulator to localise the myoneural junction. A total of 153 muscle groups were injected.

Hamstring tightness improved as a result of ethanol injection, the popliteal angle reducing from a mean of 73° (range 40° – 90°) to 43° (range 10° – 70°). Gastrocnemius tightness also improved, the ankle dorsiflexion with knee extended improving from a mean of −7° to +3°.

The maximal effect was achieved in a mean of 12 weeks and was maintained for a further 12 weeks before starting to deteriorate. The time from injection to the next intervention ranged from 13 weeks to over 2 years. There were no complications or adverse effects.

The effect of any one therapy in cerebral palsy is difficult to establish, given that there are often several different modalities of treatment operating concurrently. However, the results from this series indicate that myoneural blockade with ethanol is a useful and safe adjunct to other therapies in the child with lower limb spasticity.