Dolph Houben

156 CHAPTER 8 Abstract Clinical attempts of complete joint allotransplantation in the past have generally resulted in rejection and graft failure. The necessity to better understand the (patho) physiology of knee allotransplants in a pre-clinical model is crucial in order to study the use of vascularized joint allotransplantation for the reconstruction of large joint defects. In this paper, we describe a novel large animal model to study orthotopic vascularized whole knee joint allotransplantation with short-term immunosuppression and autologous revascularization. We performed an anatomy study and feasibility study on allotransplantation of a vascularized whole knee joint with autologous arteriovenous bundle implantation covered by a pedicled gracilis muscle flap in three outbred farm pigs. All animals received two weeks of multi-drug immunosuppressive therapy. All animals had to be sacrificed two weeks after transplantation due to the development of infected seromas. The radiographic and histologic evaluation showed that the allotransplants were viable at the time of sacrifice, but infected due to complications. We have demonstrated an experimental large animal model of knee joint allotransplantation. Despite best efforts, all experimental animals developed wound infections despite pedicled muscle flap coverage and would closure and protection methods used in the same animals successfully for tibial transplants in the past. The complexity, expense and complications make investigation of vascularized whole knee transplantation in a large animal experimental model challenging. Eventual success with modified postoperative care would permit a better understanding of large joint transplantation for possible future clinical use.