THE EFFECT OF FEMORAL TUNNEL POSITION AND GRAFT TENSIONING TECHNIQUE ON POSTERIOR LAXITY OF THE POSTERIOR CRUCIATE LIGAMENT-RECONSTRUCTED KNEE

We report the effects of femoral tunnel position and graft tensioning technique on posterior laxity of the posterior cruciate ligament-recon structed knee. An isometric femoral tunnel site was located using a sp ecially designed alignment jig. Additional femoral tunnel positions we re located 5 mm proximal and distal to the isometric femoral tunnel. W ith the graft in the proximal femoral tunnel, graft tension decreased as the knee flexed; with the graft in the distal femoral tunnel, graft tension increased as the knee flexed. When the graft was placed in th e isometric femoral tunnel, a nearly isometric graft tension was maint ained between 0 degrees and 90 degrees of knee flexion. One technique tested was tensioning the graft at 90 degrees of knee flexion while ap plying an anterior drawer force of 156 N to the tibia. This technique restored statistically normal posterior stability to the posterior cru ciate ligament-deficient knee between 0 degrees and 90 degrees for the distal femoral tunnel position, between 0 degrees and 75 degrees for the isometric tunnel position, and between 0 degrees and 45 degrees fo r the proximal tunnel position. When the graft was tensioned with the knee in full extension and without the application of an anterior draw er force, posterior translation of the reconstructed knee was signific antly different from that of the intact knee between 15 degrees and 90 degrees for all femoral tunnel positions.