Pie-crusting technique is effective and safe to release superficial medial collateral ligament for total knee arthroplasty

BACKGROUND: Pie-crusting technique is a damage-control soft tissue balance skill of total knee arthroplasty (TKA). The outcome of this technique to release lateral soft tissue is reasonable. A limited number of studies have focused on medial collateral ligament release with pie-crusting technique in the past years because of concerns about its efficacy and safety. METHOD: All cases underwent superficial medial collateral ligament (SMCL) release with either pie-crusting technique or traditional technique (39 knees in each group) between January 1, 2014 and August 31, 2015. A comparison study between two techniques was performed; meanwhile, 23 patients (26 knees) in pie-crusting group were followed up. Data including knee function, radiographic result and complications were analysed. RESULTS: Comparison study demonstrates that pie-crusting technique can achieve a comparable or even better effect of alignment correction. Data of follow-up patients are reasonable. The mean postoperative flexion contracture is 1.2 ± 3.6°. The mean postoperative motion arrange is 104.0 ± 14.4°. The mean postoperative hospital for special surgery knee score point is 82.0 ± 7.4 points. The mean postoperative femoral tibial angle is 172.4 ± 2.0°. The level of joint line elevates around 2.1 ± 1.9 mm. There are four knees that use brace after operation, and none of them present unstable knee. No severe complication has been reported, and most patients were satisfied with life quality. CONCLUSIONS: Using pie-crusting technique to release SMCL for TKA is effective and safe. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: Although pie-crusting technique has been used in TKA for years, it is seldom chosen to release medial collateral ligament, especially to release SMCL, which is a vital step of malalignment correction. This study aims to evaluate the efficacy and safety of this technique in total knee arthroplasty patients.