The predictive effect of anatomic femoral and tibial graft tunnel placement in posterior cruciate ligament reconstruction on functional and radiological outcome.

Purpose: Biomechanical reports have advocated anatomic graft tunnel placement for reconstruction of the posterior cruciate ligament (PCL) to restore knee joint stability and facilitate optimal functional outcome. However, in vivo investigations that correlate tunnel position to functional results are lacking so far. This study evaluates the anatomic accuracy of femoral and tibial tunnel apertures on postoperative computed tomography (CT) scans and compares these findings to subjective and objective clinical outcome parameters.

Methods: After single-bundle PCL reconstruction, 29 patients were stratified into several subgroups according to the anatomic accuracy of femoral and tibial tunnel apertures measured on postoperative CT scans. A threshold value for the centres of the tunnel apertures was determined using a measurement grid system as a radiographic reference. To evaluate the functional and radiological results, visual analogue scale, International Knee Documentation Committee (IKDC), Tegner, Lysholm, Knee Injury and Osteoarthritis Outcome Score and osteoarthritis scores were obtained.

Results: Comparison between functional outcome and tunnel position yielded a statistically significant difference for subjective IKDC score and angle segment α and for objective stability and tunnel position P3 but no statistically significant difference with respect to intercondylar depth, intercondylar height and tibial tunnel position P2. No correlation was found between anatomic tunnel position and present or progressive osteoarthritis on follow-up. Of the patients, 72 % classified their result as excellent and good and 90 % would repeat surgical treatment.

Conclusions: Despite a small sample size and subject to the threshold values we used, our data indicate a potentially minor effect of anatomic tunnel placement on midterm functional outcome following PCL reconstruction.