Post-operative knee adduction moment is associated with patient-reported outcome improvements after medial opening wedge high tibial osteotomy

Purpose: This study aimed to evaluate the relationship between post-operative knee adduction moment (KAM) and patient-reported outcome measures (PROMs) after medial opening wedge high tibial osteotomy (MOWHTO). Methods: A retrospective analysis was conducted on 40 patients who underwent MOWHTO. Radiographic assessments, including hip–knee–ankle angle, were performed pre-operatively and 6 months post-operatively. Dynamic three-dimensional gait analysis was conducted pre-operatively and at 6 months to measure KAM 1st peak. PROMs were evaluated using the WOMAC total score pre-operatively and at 12 months. Pearson correlation analysis examined the relationship between post-operative KAM 1st peak and ΔWOMAC total score. Receiver operating characteristic (ROC) analysis was performed as an exploratory analysis to assess the relationship with the minimal clinically important difference (MCID). Results: KAM 1st peak significantly decreased by 53% post-operatively (p < 0.001). A significant positive correlation was observed between post-operative KAM 1st peak and ΔWOMAC total score (r = 0.325, p = 0.020). Exploratory ROC analysis suggested a potential threshold of 25.7 Nm for achieving the MCID. Conclusions: While reducing KAM is a primary goal of MOWHTO, excessively low post-operative KAM values may be associated with reduced improvements in PROMs. These findings suggest that achieving an optimal range of correction, rather than simply minimizing KAM, may be important for optimizing post-operative outcomes and highlight the potential value of incorporating dynamic biomechanical assessment.