Investigation of lateral hinge fracture in open wedge around knee osteotomy

Background: Open-wedge osteotomy is a widely adopted surgical technique for treating varus knee osteoarthritis. Distal tuberosity osteotomy (DTO) was developed to prevent patellofemoral joint (PFJ) complications; however, its impact on the risk of lateral hinge fracture (LHF) remains unclear. Objectives: This study aimed to compare the incidence of LHF between conventional high tibial osteotomy (HTO) and DTO, and to identify potential radiographic risk factors associated with LHF. Methods: This retrospective study included 82 knees (DTO: 36; HTO: 46) that underwent osteotomy between October 2021 and November 2024. Radiographic evaluations included the hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), fibular height, osteotomy gap height (open height), and the line-to-tip distance (LTD) from the osteotomy line to the fibular tip. The presence of LHF was assessed postoperatively. Statistical analysis was conducted using Student's t-test and chi-square test. Results: LHF occurred in 55.6 % of DTO cases versus 13.0 % in HTO cases (p < 0.05). The open height and LTD were significantly greater in the DTO and LHF-positive groups. No significant differences were observed in preoperative HKA, MPTA, or fibular height between the groups. Within the DTO group, LHF-positive cases had significantly larger LTD compared to LHF-negative cases, while no significant difference was found within the HTO group. Conclusion: DTO is associated with a significantly higher risk of LHF compared to conventional HTO. Greater osteotomy gap height and a more distal hinge position (below the fibular tip) appear to contribute to LHF development. Surgeons should consider alternative osteotomy techniques or intraoperative strategies to minimize the risk of LHF, particularly in cases requiring large corrections or with high fibular head anatomy.