Moon HS, Choi CH, Yoo JH, et al. - In this study, relevant factors influencing increases in medial joint space width (JSW) after medial open-wedge high tibial osteotomy (MOWHTO) were tested. Researchers retrospectively examined the electronic medical records of consecutive patients who underwent MOWHTO and subsequent second-look arthroscopic assessment at least 12 months after MOWHTO between January 2010 and December 2018. Individuals were categorized into two groups according to variations in the medial JSW of the knee at the time of second-look operation, compared to that at baseline before the initial surgery. A sum of 114 individuals was examined in the study. After MOWHTO, an increase in the medial JSW of the knee joint seems to be correlated with an increase in postoperative weight-bearing line ratios (WBLR), not with cartilage regeneration. This study's findings demonstrate that obtaining adequate correction so that postoperative WBLR is within 60-70% would be desirable in terms of postoperative changes in medial JSW, as well as clinical outcomes.