The Effect of Femoral Tunnel Position and Graft Tensioning Technique on Posterior Laxity of the Posterior Cruciate Ligament-Reconstructed Knee

Abstract

We report the effects of femoral tunnel position and graft tensioning technique on posterior laxity of the posterior cruciate ligament-reconstructed knee. An isometric femoral tunnel site was located using a specially de signed alignment jig. Additional femoral tunnel positions were located 5 mm proximal and distal to the isometric femoral tunnel. With the graft in the proximal femoral tunnel, graft tension decreased as the knee flexed; with the graft in the distal femoral tunnel, graft tension in creased as the knee flexed. When the graft was placed in the isometric femoral tunnel, a nearly isometric graft tension was maintained between 0° and 90° of knee flexion. One technique tested was tensioning the graft at 90° of knee flexion while applying an anterior drawer force of 156 N to the tibia. This technique restored sta tistically normal posterior stability to the posterior cru ciate ligament-deficient knee between 0° and 90° for the distal femoral tunnel position, between 0° and 75° for the isometric tunnel position, and between 0° and 45° for the proximal tunnel position. When the graft was tensioned with the knee in full extension and without the application of an anterior drawer force, posterior trans lation of the reconstructed knee was significantly dif ferent from that of the intact knee between 15° and 90° for all femoral tunnel positions.