Does Superficial Medial Collateral Ligament Release in Open-Wedge High Tibial Osteotomy for Varus Osteoarthritic Knees Increase Valgus Laxity?

Background:Medial open-wedge high tibial osteotomy (OWHTO) requires the release of the superficial medial collateral ligament (sMCL). However, research on medial laxity among patients who undergo OWHTO is rare.Purpose:To evaluate the changes in medial laxity of the knee joint as related to the complete release of the sMCL through serial valgus stress radiographs in patients who underwent OWHTO.Study Design:Cohort study; Level of evidence, 2.Methods:A total of 48 patients (54 knees) who received OWHTO and were followed for more than a year and for whom serial valgus stress radiography data were available were retrospectively reviewed. To assess the medial laxity of knee joint, medial joint space opening (MJO) was measured while valgus stress of 15 kgf was loaded on the knee joint. The MJO was measured before surgery, during surgery before release of the sMCL under anesthesia, after the release, and after fixing with a TomoFix plate following the opening of the osteotomy site, as well as 3, 6, and 12 months...