Lateral Opening-Wedge Versus Medial Closing-Wedge Distal Femoral Osteotomy for Adolescent Idiopathic Genu Valgum: A Randomised Controlled Trial

BACKGROUND: Distal femoral osteotomy is used to correct symptomatic genu valgum after distal femoral physeal closure, but comparative evidence between lateral opening-wedge osteotomy (LOW) and medial closing-wedge osteotomy (MCW) in adolescents is limited. We compared radiographic correction, recovery, and complications between the techniques. METHODS: In this prospective randomised trial, 65 adolescents aged 12 to 18 years with idiopathic genu valgum and radiographic closure of the distal femoral physis were allocated 1:1 to LOW or MCW. Three participants were lost to follow-up, leaving 62 participants for the available-case analysis (LOW, n=32; MCW, n=30). In bilateral cases, only the first operated limb was analyzed. The primary outcome was signed mechanical axis deviation (MAD) at radiographic union; unadjusted comparisons were the primary focus, and covariate-adjusted analyses were supportive. RESULTS: MAD at union was 6.8±6.2 mm after LOW and 2.4±5.3 mm after MCW (LOW minus MCW, 4.4 mm; 95% CI: 1.5-7.3; P=0.003). The supportive adjusted difference was 3.0 mm (95% CI: -0.4 to 6.5; P=0.08). Absolute deviation from neutral was 6.8±6.2 versus 4.0±4.1 mm (difference, 2.8 mm; 95% CI: 0.2-5.5; P=0.04). At union, mLDFA did not differ significantly; aLDFA favored MCW in the unadjusted analysis, but neither adjusted angular difference was significant. One-year Pedi-IKDC scores, pain, satisfaction, union time, hospital stay, and return to activity did not differ between groups. Unique symptomatic lateral plate/iliotibial-band irritation occurred in 4 of 32 LOW participants (13%) and 3 of 30 MCW participants (10%; P=1.00). CONCLUSIONS: MAD at radiographic union favored MCW, but the trial did not establish clinically meaningful superiority. The adjusted estimate was smaller and nonsignificant, and no sustained functional advantage was detected. Both techniques produced substantial correction with favorable short- to mid-term outcomes. LEVEL OF EVIDENCE: Level I-therapeutic study.