Combined Proximal and Distal Tibial Fixation in Posterior Cruciate Ligament Reconstruction

INTRODUCTION: Despite the recent advances in our understanding of the anatomy and biomechanics of the posterior cruciate ligament (PCL), current methods of PCL reconstruction continue to lack the clinical success that anterior cruciate ligament (ACL) reconstruction has experienced, with many patients developing residual posterior laxity following surgery [1]. One variable that directly affects the load-elongation behavior of the graft – and thereby the laxity after reconstruction – is the length of the graft between its fixation points (i.e. the effective graft length). It was found that the closer the fixation was located to the ligament insertions, the stiffer the graft [2]. Historically, the most common method for tibial fixation during PCL reconstruction used the transtibial technique, in which the graft – fixed distally in the tibial tunnel with an anterior screw – passes proximally and posteriorly through the tibia, makes a 90° turn around the superior edge of the posterior aperture of the tibial tunnel before entering the knee joint. A tibial inlay technique was developed to provide a more anatomic site of tibial fixation, eliminating the “killer turn” that was thought to contribute to graft elongation and residual posterior laxity. However, the tibial inlay technique has an increased operative time, and added risks of surgery due to the proximity of the neurovascular structures and variability in the posterior vascular anatomy. In addition, the effective graft length remained longer than the native PCL’s length. Based on the stiffness testing data, an aperture fixation, whereby the graft is fixed at the proximal aperture of the transtibial tunnel, creating the shortest possible graft, would be preferable. Cadaveric testing demonstrated that a combined proximal and distal tibial fixation in PCL reconstruction indeed decreased the effective graft length and increased the stiffness of the PCL graft, resulting in significantly less posterior tibial translation, as compared to the transtibial technique [3]. However, the results of this study applied only to the time of initial graft fixation and did not reflect in-vivo graft performance over time. The objective of this study was to evaluate the clinical outcome of the combined proximal and distal tibial fixation technique in PCL reconstruction.