Outcome of allogeneic vascularized knee transplants

Transplantation of vascularized knee joints is a novel approach in Composite Tissue Allotransplantation (CTA). In 1996 our group started a clinical knee transplantation project and six transplantations have been performed since. Key problems identified early were the monitoring of acute rejection and choice of an immunosuppressive regime. One graft was lost due to postoperative infection and one due to of noncompliance where the patient discontinued the immunosuppressant regime. In three cases late rejection lead to necrosis and graft dysfunction after 15, 16 and 24 months, respectively. Exit-strategies were arthrodesis in one patient and Above Knee Amputation in two cases. With retrospective analysis after initial five cases the treatment protocol was improved. The immunosuppressive drug regime was altered, femoral diaphysis and knee joint grafting was combined and a vascularized block of donor skin and subcutaneous tissue was harvested with the graft (sentinel skin graft). The sentinel skin graft enabled us to monitor acute rejection by clinical and histological examination and avoid late rejection by rapid treatment with high dose steroids. In summary, over a four-year period, one of six allogeneic vascularized knee transplants has survived, one was lost from a surgical site infection, one by noncompliance and three by late rejection. Analysis of our data leads us to suggest that knee transplantation should be limited to a combined injury consisting of extensive loss of cartilage and bone, deficient extensor mechanism and soft tissue and skin defects without any signs of infection. Transplantation should only be taken into consideration as last option before Above Knee Amputation in an otherwise healthy patient under 35 years of age.