Pigmented villonodular synovitis (PVNS) is a rare benign disease of the synovium of joints and tendon sheaths, which may be locally aggressive. We present 18 patients with diffuse-type PVNS of the foot and ankle followed for a mean of 5.1 years (2 to 11.8). There were seven men and 11 women, with a mean age of 42 years (18 to 73). A total of 13 patients underwent open or arthroscopic synovectomy, without post-operative radiotherapy. One had surgery at the referring unit before presentation with residual tibiotalar PVNS. The four patients who were managed non-operatively remain symptomatically controlled and under clinical and radiological surveillance. At final follow-up the mean Musculoskeletal Tumour Society score was 93.8% (95% confidence interval (CI) 85 to 100), the mean Toronto Extremity Salvage Score was 92 (95% CI 82 to 100) and the mean American Academy of Orthopaedic Surgeons foot and ankle score was 89 (95% CI 79 to 100). The lesion in the patient with residual PVNS resolved radiologically without further intervention six years after surgery. Targeted synovectomy without adjuvant radiotherapy can result in excellent outcomes, without recurrence. Asymptomatic patients can be successfully managed non-operatively. This is the first series to report clinical outcome scores for patients with diffuse-type PVNS of the foot and ankle.

Cite this article: Bone Joint J 2013;95-B:384–90.

A 36 year old gentleman presented to the Metabolic Bone Disease Clinic with a progressive history of thoracic and lower limb pain. He had originally been seen by the podiatrists with worsening foot pain for which no cause had been found. Initial investigation revealed a hypophosphataemic osteomalacia and a bone scan demonstrated multiple abnormalities suggesting old fractures.

Investigations were performed to establish the cause of the osteomalacia and we discuss the differential diagnosis and the progression towards a diagnosis based on the results of these tests. The most useful investigation in this case was an octreotide scan which indicated the presence of an endocrine tumour in the medial femoral condyle of the right knee.

Plain x-rays revealed no clear bony abnormality in the area of increased uptake on the octreotide scan. The lesion was therefore localised with an MRI scan.

This subsequently demonstrated the exact location of the lesion and in image guided biopsy was performed in theatre. This confirmed the presence of a benign Phosphaturic Mesenchymal tumour. This rare tumour is usually found in soft tissues and this case is atypical given that the lesion was wholly within the femoral condyle.

Despite the benign appearance of the tumour cells there were some areas of locally invasive growth and excision rather than curettage of the tumour was recommended. It was possible to preserve both the bulk of the femoral condyle and the articular surface although the knee was protected with a hinged brace for six weeks following surgery.

Follow up biochemistry results demonstrate that the serum phosphate and alkaline phosphatase are returning to normal. Symptomatically the patient is much improved.

A case of pencil-gore granuloma occurring 45 years after the initial injury is described. The clinical and radiological presentation was suggestive of a soft-tissue sarcoma. The diagnosis was confirmed by biopsy, which also revealed foreign body fragments which, on spectometric analysis, had high concentrations of carbon and aluminium.

We studied 55 patients with stage-IIB osteosarcoma around the knee with respect to the expression of matrix metalloproteinase (MMP)-9 in the surviving tumour cells in surgical resection specimens. They were followed up for a minimum of 2.5 years.

Factors significantly associated with poor overall survival were a high serum level of alkaline phosphatase at diagnosis and tumour cells expressing MMP-9 in the resection specimens. The only factor strongly associated with disease-free survival was the immunohistochemical status of tumour cells for MMP-9 in the resection specimens. The percentage of necrosis after chemotherapy failed marginally to reach statistical significance. On Cox regression analysis only MMP-9 remained significant for overall and disease-free survival.

We studied 153 patients with non-metastatic chondrosarcoma of bone to determine the risk factors for survival and local tumour control. The minimum follow-up was for five years; 52 patients had axial and 101 appendicular tumours. Surgical treatment was by amputation in 27 and limb-preserving surgery in 126.

The cumulative rate of survival of all patients, at 10 and 15 years, was 70% and 63%, respectively; 40 patients developed a local recurrence between 3 and 87 months after surgery and 49 developed metastases. Local recurrence was associated with poor survival in patients with concomitant metastases but not in those without.

On multivariate analysis independent risk factors for rates of survival include extracompartmental spread, development of local recurrence and high histological grade. Independent risk factors for local recurrence include inadequate surgical margins and tumour size greater than 10 cm. Location within the body, the type of surgery and the duration of symptoms are of no prognostic significance. Surgical excision with an oncologically wide margin provides the best prospect both for cure and local control in these patients.

Dedifferentiated chondrosarcoma is a rare, highly malignant variant of chondrosarcoma in which a high-grade spindle-cell sarcoma coexists with a lower-grade chondroid tumour. We have reviewed our experience with this neoplasm in 22 patients, all of whom were treated using modern oncological principles of planned resection and chemotherapy. Despite this the median survival was under nine months and only 18% were alive at five years. Those patients who received chemotherapy, and in whom wide margins of excision were achieved at operation, did best. It is essential to have an accurate preoperative diagnosis in order to plan treatment which may offer a better prospect of cure.

Over a 25-year period we have treated 36 patients with osteosarcoma of the pelvis. Of the tumours, 24 (67%) were primary osteosarcomas and 12 (33%) arose either after irradiation or in association with Paget’s disease. Six patients had a hindquarter amputation and 12 were treated by a limb-salvage procedure with intrapelvic excision.

The five-year survival rate of all the patients with pelvic osteosarcoma was 18%, while for 17 treated by chemotherapy and surgery it was 41%. The prognosis for patients presenting with metastases or with secondary osteosarcoma was appalling and none survived after 29 months. No patient over the age of 50 years when seen initially survived for a year. Youth and a good response to chemotherapy along with complete surgical excision offer the best chance of cure.

We studied the CT and MR scans, and the histology of 50 patients with primary Ewing’s sarcoma of bone to determine the association between the change in tumour volume and necrosis after chemotherapy, and to ascertain their influence on prognosis. The mean age of the patients was 17 years. The limbs were involved in 40 and the axial bones in ten. The volume of the tumour at diagnosis varied from 31 to 1790 ml.

There was a significant relationship between necrosis and the measured change in volume of the tumour after chemotherapy. Progression of the tumour despite chemotherapy was seen only in patients with necrosis of grades 4 to 6. Necrosis significantly influenced survival (p < 0.05), but the effect of change in volume was less significant.

Change in volume of the tumour is a good predictor of necrosis induced by chemotherapy. Necrosis is a strong prognostic factor in Ewing’s sarcoma.

Amyloidoma of soft tissue is rare and there have been no previously published reports of limb involvement. We describe a case in which the tumour was present in the popliteal fossa. There was no evidence of systemic amyloid disease or of malignant neoplasm one year after the diagnosis.