Kim GB, et al. - Between July 2010 and March 2016, 164 knees were studied to explore the differences along with the predisposing factors in posterior tibial slope angle (PTSA) and the anterior cruciate ligament (ACL) before and after medial open-wedge high tibial osteotomy (MOWHTO) through two-staged arthroscopic findings and also to confirm if the ACLs would be affected by the changed PTSA. The time interval between the two-stage arthroscopies was 26.3±4.0 months. They noted that PTSA significantly increased following MOWHTO. As compared to first-look findings, ACL stage at second-look arthroscopy was significantly progressed. They noticed larger △PTSA (changes in PTSA) in the progressed group (2.1°). Greater BMI and larger △PTSA were indicated as predisposing factors in multivariate logistic regression.