Anterior cruciate ligament reconstruction using bone-patellar tendon-bone allografts: A biological and biomechanical evaluation in goats

Twenty-eight goats underwent ACL reconstruction with freeze-dried bone-patellar tendon-bone allografts in one knee, the opposite knee serving as a control. One group of 16 knees was evaluated, in groups of four, at 6, 12, 26, and 52 weeks by histologic and vascular injection techniques. The other group of 12 knees was evaluated in two groups of six at 26 and 52 weeks by morpholog ical and biomechanical techniques of analysis. Within the first 12 weeks these allografts were revas cularized; in the first 26 weeks they had matured to resemble normal connective tissue. Graft stiffness was 29% of the control value and maximum force to failure was 43% of the control value. The results of this study indicated that freeze-dried bone-patellar tendon-bone allografts are biomechani cally and biologically similar to patellar tendon auto- grafts.