Postoperative Joint Line Convergence Angle (JLCA) following high tibial osteotomy is affected not only by preoperative JLCA but also by postoperative hip-knee-ankle angle.

Purpose: Accurate preoperative planning for high tibial osteotomy (HTO) requires understanding the factors influencing postoperative joint line convergence angle (JLCA). This study aimed to identify independent predictors of postoperative absolute JLCA and its change from preoperative values (ΔJLCA). Methods: Radiological assessments were performed on 113 knees from 109 patients who underwent inverted V-shaped high tibial osteotomy (iV-HTO), both preoperatively and 1 year postoperatively, using radiographs taken in standing and supine positions. Prior to univariate and multiple regression analyses, the knees were divided into two Groups S (preoperative JLCA ≤ 2°) and G (preoperative JLCA > 2°). To explore affecting factors, first, univariate regression analysis was performed to assess the correlation between each of the demographic and radiographic parameters and each of the postoperative JLCA and ΔJLCA. Then, multiple regression analyses were performed separately for postoperative JLCA and ΔJLCA, using the significant parameters identified in the univariate regression analysis as explanatory variables. Results: In Group G, the postoperative JLCA (mean, 2.5°) was significantly reduced ( Conclusion: The postoperative absolute JLCA was significantly affected not only by the preoperative JLCA but also by the postoperative HKA. In HTO for OA knees with a large JLCA, maximal JLCA reduction requires a preoperative plan aiming at the greatest clinically acceptable valgus HKA and a suitable surgical procedure. Level of Evidence: Level II, cohort study.