Dolph Houben

166 CHAPTER 8 Figure 8: blood cell counts at base line, 1 and two weeks after transplantation followed by time of sacrifice (last time point). Discussion Allotransplantation of vascularized bone, joint, face and hands present an ethical dilemma [14, 18] . The risks, expense and complications of life-long immunosuppression need to be carefully considered in these non-life-critical transplantations, particularly if other reconstructive methods are possible. Only a few allogenic knee joint transplantations have been performed in human. All of these clinical attempts have had poor outcomes, ultimately requiring an above-knee amputation [1, 5, 7, 8, 10] . Given the clinical outcomes reported to date, joint allotransplantation at present remains an unproven reconstructive method. Experimental whole knee joint transplantation has been performed in several large and small animal models, showing the procedure to be technically feasible [12, 15, 19, 20] . In a canine knee joint model, vascularized autografts healed and functioned without problem, but identical allotransplants were rejected within a few days in the absence of immunotherapy [12] . Vascular endothelium is highly immunogenic, causing vascular thrombosis and death of the allotransplanted tissue days to a few weeks without adequate immune suppression [1, 10, 12] .