A biomechanical comparison of posterior cruciate ligament reconstruction techniques.

Most posterior cruciate ligament reconstruction techniques use both tibial and femoral bone tunnels for graft placement. Because of the acute angle the graft must make to gain entrance into the tibial tunnel, abnormal stresses are placed on the graft that could lead to graft failure. An alternative technique for posterior cruciate ligament reconstruction involves placement of the bone plug from the graft anatomically on the back of the tibia (inlay), preventing formation of an acute angle at the tibial attachment site. We used six pairs of human cadaver knees to compare the biomechanical properties of these two techniques. One knee from each pair underwent tunnel reconstruction while the other knee underwent inlay reconstruction. There was significantly less anterior-posterior laxity in the inlay group when compared with the tunnel group from 30 degrees to 90 degrees of knee flexion and after repetitive loading at 90 degrees of knee flexion. Evaluation of the grafts revealed evidence of mechanical degradation in the tunnel group but not in the inlay group. The inlay technique resulted in less posterior translation with less graft degradation than did the tunnel technique for posterior cruciate ligament reconstruction.