Comparison of cruciate retaining and PCL sacrificing TKA with respect to medial and lateral gap differences in varus knees after medial release.

We aimed to clarify whether the increase in medial gap after medial release is influenced by the retention or sacrifice of posterior cruciate ligament (PCL) during navigation-assisted total knee arthroplasty. After matched pairs were done according to the equality of preoperative varus deformity and medial collateral laxity, 54 knees of each type were available for this study. In the PCL sacrificing group, the mediolateral gap difference significantly increased in both flexion and extension as the preoperative mechanical axis angle increased whereas in the cruciate retaining group, the mediolateral gap difference did not show this tendency. When preoperative mechanical axis angles were over 10.4° in extension and over 7.7° in flexion, the medial gap showed greater increases in PCL sacrificing groups than in cruciate retaining groups.