Half-joint allograft transplantation in human bone tumours.

Seven patients with malignant or aggressive bone tumours involving the end of a long bone have been treated by wide resection and an allograft providing a half-joint transplantation. The observation period is from 2 to 9 years (average 5 years). The allografts were preserved at -70 degrees C for a period ranging from 1 week to more than 2 years. Computed tomography was very useful in the preoperative determination of the grade of infiltration tumour growth in bone. The host's own ligaments were used in the reconstruction. Immunosuppression was not used. The fate and metabolism of the allografts were followed by clinical examination, conventional radiographs, angiography, bone scintigraphy, cell-mediated immunity tests, biopsies for histology and by determining the excretion of the urinary products of bone metabolism (duHYPro, dUCa, dUPi). Positive isotope labelling was demonstrated as early as 2 weeks after transplantation and this increased and stabilised at about 6 months. Simultaneously, the collagen/bone matrix turnover (HYPro excretion) showed a slightly raised level for up to 3-6 months, stabilising thereafter indicating a moderate, but prolonged, regenerative activity of the graft. On the basis of these and the histological studies, weight-bearing was gradually started at 6 months, which is earlier than described in previous reports. The patients had knee flexion up to 90 degrees and walked well. Studies on whole-blood cell-mediated immunity showed only slight non-significant changes. The results indicate that the grafts incorporated well with early, and subsequently prolonged, evidence of metabolic activity.