Effect of physiological posterolateral rotatory laxity on early results of posterior cruciate ligament reconstruction with posterolateral corner reconstruction.

Background: The purpose of this study was to evaluate the influence of physiological posterolateral rotatory laxity on posterior cruciate ligament (PCL) reconstruction in terms of posterior stability and clinical outcomes.

Methods: We retrospectively reviewed the records of sixty-five patients who had undergone arthroscopic PCL reconstruction with simultaneous reconstruction of the posterolateral corner from March 2004 to April 2009. Patients were categorized into three groups according to the amount of tibial external rotation at 90° of knee flexion on the uninjured side: Group 1 (<40°; n = 26), Group 2 (between 40° and 50°; n = 21), and Group 3 (>50°; n = 18). Knee instability was assessed with posterior and varus stress radiographs as well as with the dial test at 30° and 90° of knee flexion. Functional scores were assessed with use of the Lysholm score and the International Knee Documentation Committee (IKDC) score preoperatively and at the time of final follow-up.

Results: At the time of follow-up, there was no significant difference among the three groups with regard to the mean side-to-side difference in posterior translation as measured with Telos stress radiography (Group 1: 3.6 ± 1.3 mm, Group 2: 3.3 ± 1.6 mm, and Group 3: 4.3 ± 1.6 mm; p = 0.098). There was also no significant difference among the groups with respect to knee stability as assessed on the varus stress radiographs or with the dial test at 30° and 90° of flexion. Finally, there was no significant difference among the groups with respect to the Lysholm or IKDC functional scores.

Conclusions: This study suggests that the instability of knees that have PCL and posterolateral corner injuries with physiological posterolateral rotatory laxity can be controlled successfully with PCL reconstruction and simultaneous reconstruction of the posterolateral corner. Physiological posterolateral rotatory laxity should not be considered a risk factor for abnormal knee laxity after PCL reconstruction with simultaneous reconstruction of the posterolateral corner.