We present the results in 12 patients of arthrodesis of the knee using a vascularised fibular graft after resection of a malignant bone tumour. At a mean follow-up of 95 months (60 to 178) all patients were free from disease although 11 had had at least one complication, with stress fracture of the graft in five patients, nonunion in two and deep infection requiring above-knee amputation in one. Despite the high rate of complications, satisfactory results can be obtained using this technique. Careful preoperative counselling is required