Endoscopic ACL reconstruction using stryker biosteon cross-pin femoral fixation and interlock cross-pin tibial fixation.

Hamstring tendon autografts have, over the past decade, increasingly become the graft of choice for anterior cruciate ligament (ACL) reconstructions. Studies have shown that multiply stranded hamstring grafts have superior biomechanical characteristics when compared to patellar tendon autografts. Harvests of hamstring tendons have been shown to cause less donor-site morbidity than the harvest of patellar bone-tendon-bone grafts. Historically, however, fixation methods for hamstring grafts have limited their successful use. Fixation for both the tibia and femur distant from the intra-articular portions of the graft decreased the stiffness of the construct. The fixation also contributed to tunnel widening and ganglion formation. New methods have been developed to maximize the mechanical strengths of hamstring grafts and optimize biological factors in healing of the graft to the bone tunnels. Femoral cross-pin fixation provides secure fixation close to the knee joint, while also allowing for placement of the graft in the native ACL footprint at the far posterior aspect of the intercondylar notch. Tibial interference screw fixation allows fixation close to the joint as well. Addition of the interlock pin through the interference screw increases pullout strength significantly. Recent advances in material science have led to the development of bioabsorbable implants that afford high initial fixation strengths while limiting subsequent complications from permanent hardware.