In immature long bones, radical excision of malignant tumours of the metaphysis may necessitate sacrifice of the adjacent epiphysis. To preserve the adjacent joint while allowing a safe margin of excision, we used physeal distraction before removing the tumour. From July 1984 to August 1992, we operated on 20 patients by this method. After a mean follow-up of 54 months there was no local recurrence in the epiphyseal region. Three patients had developed pulmonary metastases.

We investigated the lymphocyte-mediated immune response to polymethylmethacrylate bone cement in 26 patients who had revision surgery for aseptic loosening of cemented total hip arthroplasties, at a mean time of seven years after the first replacement. We studied eight patients with cemented total hip arthroplasties which were not loose as controls. Patch tests to polymethylmethacrylate bone cement were positive in 13 patients with loosening, and these patients had higher lymphoblast transformation values against polymethylmethacrylate bone cement patients with a negative skin reaction (p < 0.01) or those in the control group (p < 0.001). Specific monoclonal antibodies were used to assess the percentage of certain cells of the immune system according to their cluster of differentiation (CD). There was a higher number of total T and B lymphocytes (CD2 and CD22) and interleukin-2 receptor-positive lymphocytes (activated cells, CD25) in patients with loose prostheses. More CD25 lymphocytes were found in patients with positive patch tests. The activation of the lymphocyte-mediated immune response was not related to the presence or absence of aggressive granulomatous lesions at the cement-bone interface.

Limb lengthening by means of distraction through the callus of a knee arthrodesis was performed in a 14-year-old boy with congenital hypoplasia of one lower limb. Knee arthrodesis was indicated because of destruction of the distal femoral epiphysis caused by a previous bone lengthening procedure.