Anterior cruciate ligament allograft transplantation

In recent years much effort has been devoted to finding a satisfactory replacement for the injured ACL. None of the reconstruction techniques used in the past can be considered ideal because of their inability to dupli cate the complex geometry, structure, and function of the ligament. Current advances in allograft transplan tation and cryopreservation have led us to design and implement an experimental model for testing the feasi bility of cryopreserved ACL allotransplantation. Groups of dogs were used to evaluate the effect of cryopreservation on ligament strength and to compare the relative performance of both autograft and allograft ACL transplants up to 18 months after implantation. The ligaments were examined mechanically, histologi cally, and microangiographically. The cryopreservation process and duration of stor age had no effect on the biomechanical or structural properties of the ligament. The mechanical integrity of the allografts was similar to that of the autografts, with both achieving nearly 90% of control ligament strength by 36 weeks. Revascularization approached normal by 24 weeks in both autograft and allograft. No evidence of structural degradation or immunological reaction was seen. Based on these results, we believe that a cryopre served ACL allograft can provide the ideal material for ACL reconstruction. We have outlined a surgical tech nique for harvesting and implanting this graft clinically.