Impact of intraoperative lateral hinge fracture on early clinical and radiological outcomes following open wedge high-tibial osteotomy

BACKGROUND: Medial opening-wedge high tibial osteotomy (MOWHTO) is a primary intervention for varus knee malalignment. However, the specific impact of lateral hinge fracture (LHF) on early functional recovery and unintended radiological deviations remains previously unresolved. we aimed to investigate the influence of LHF on short-term patient-reported outcomes, weight-bearing progression, and sagittal alignment. METHODS: This retrospective cohort study (n = 154) compared outcomes between patients sustaining intraoperative LHF (n = 12) and those with preserved hinges. Clinical recovery was assessed via Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analog Scale (VAS), while CT scans evaluated posterior tibial slope (PTS) and joint line convergence angle (JLCA). RESULTS: Intraoperative LHF revealed a profound delay in functional progression; 0% of LHF patients achieved independent weight-bearing by 24 weeks compared to a median of 17.0 weeks in the non-LHF group (p < 0.001). Multivariable regression demonstrated that LHF was the most substantial negative predictor of 6-month KOOS (β = - 0.493, p < 0.001) and significantly drove increased pain (β = 0.328, p < 0.001). Furthermore, LHF cases exhibited an unprecedented increase in PTS compared to controls (13.17 ± 1.37 vs. 8.95 ± 2.09, p < 0.001). CONCLUSIONS: Lateral hinge fractures significantly impair early rehabilitation and induce unintended sagittal alignment changes, which provides a new framework for prioritizing surgical precision and hinge-protective strategies.