We have made a retrospective study of 1001 custom-made prostheses used as replacements after surgery for bone tumours. There were 493 distal femoral, 263 proximal femoral and 245 proximal tibial prostheses. Aseptic loosening was shown to be the principal mode of failure of the implants, and 71 patients had revision for aseptic loosening of a cemented intramedullary stem.

The probability of a patient surviving aseptic loosening for 120 months was 93.8% for a proximal femoral replacement, 67.4% for a distal femoral prosthesis and 58% for a proximal tibial implant. In patients with distal femoral replacements the age of the patient at the time of operation and the percentage of bone resected were related to the risk of aseptic loosening. Young patients with distal femoral prostheses in whom a high percentage of the femur had been replaced had the poorest prognosis for survival without aseptic loosening. The percentage of bone removed had a significant effect in the proximal tibial replacement group, but the age of the patient did not. By contrast, neither the age nor the percentage of bone removed was a factor after proximal femoral replacement.

The significance of these findings is discussed in relation to mechanical factors.

We have reviewed 20 cases of parosteal osteosarcoma treated by wide local resection and prosthetic replacement and followed up for six to 17 years. Limb function was excellent in 85%. One patient with grade III histological disease developed pulmonary metastases. Four patients had local recurrences, which were related to repeated preliminary biopsies, inappropriate siting of biopsy and vascular encroachment by the tumour. After this mode of treatment, the outcome was not related to medullary invasion by the tumour.

We report 16 orthopaedic patients who had antibiotic-associated diarrhoea (pseudomembranous colitis) after operation. There was an association with the use of cephradine and with the prolongation of prophylaxis for more than three peri-operative doses. Five cases occurred as a cluster, suggesting that the causative agent, Clostridium difficile, may be infectious in some situations.

Forty-four patients who had undergone 50 capsular arthroplasties for congenital dislocation of the hip were reviewed after a mean follow-up of 20 years. Their average age at operation was 5.9 years; 31 of the operations were undertaken because of late presentation, the remainder because of the failure of previous surgery. In all, 70% of the hips showed good function despite a reduced range of movement, but patients with bilateral arthroplasties fared poorly. Excellent containment within the acetabulum was found in 80%, but the femoral head was always abnormally high though not unduly lateral or medial. This configuration had remained unchanged during follow-up. The accuracy of reduction along the mediolateral axis was the only variable found to influence the outcome significantly. Functional deterioration, associated with pain, was noted to be more common after 20 years than before, and was associated with radiographic evidence of joint degeneration.

A patient with recurrent dislocation of the hip is described. The initial injury had been a posterior dislocation without associated fracture of the acetabular wall, and the hip had not been immobilised or protected from weight-bearing during treatment. Exploration of the hip for recurrence revealed disruption of the posterosuperior acetabular labrum with formation of a pouch between the posterior acetabular wall and the short rotator muscles. We have found no previous report of this lesion, which resembles a Bankart lesion of the shoulder. Repair using a bone block is described.

Seven cases of massive osteolysis are presented. The aetiology of this disease is as yet unknown; neither age nor sex seems to be a factor in its incidence, nor are standard bone grafts or radiotherapy successful methods of treatment. However, in this series, operation produced a satisfactory outcome for five patients at a mean follow-up of 17 years; in three of these patients a custom-built prosthesis was inserted, and in one a conventional bone graft was combined with intramedullary nailing.