Early postoperative changes and temporal evolution of coronal alignment following medial-closing wedge distal femoral varus osteotomy: A longitudinal radiographic study.

Abstract

Distal femoral varus osteotomy (DFVO) is performed to correct valgus knee deformity, yet the temporal changes in mechanical alignment following surgery remain poorly understood. This study aimed to evaluate temporal postoperative changes in the weight-bearing line (WBL) ratio and coronal alignment parameters within the first year after medial closing-wedge DFVO. A retrospective review included patients who underwent medial closing-wedge DFVO for valgus knees with lateral unicompartmental osteoarthritis and ≥12 months of follow up between 2015 and 2024. The WBL ratio, joint-line obliquity (JLO), joint-line convergence angle (JLCA), and lateral distal femoral angle (LDFA) were measured on standardized long-leg standing radiographs acquired in the two-leg standing position and analyzed using linear mixed-effects models with Bonferroni correction. A total of 48 knees from 45 patients were included. The WBL ratio declined significantly from 82.8% at baseline to 53.6% at 3 months, 48.0% at 6 months, and 41.0% at 12 months (all P < 0.001). JLO, JLCA, and LDFA all changed significantly at each postoperative time point compared with baseline, with most changes occurring within the first 6 months; no significant differences were observed between 6 and 12 months for most parameters. Medial closing-wedge DFVO effectively corrected mechanical alignment, with coronal parameters continuing to evolve through 6 months postoperatively before stabilizing, likely attributable to soft-tissue adaptation, joint loading redistribution, and rehabilitation-driven muscle strengthening.