Clinical course and risk factors for post-operative onset lateral hinge fracture following medial opening-wedge distal tibial tuberosity osteotomy

Purpose: This study aimed to investigate the clinical outcomes of and risk factors for post-operative onset lateral hinge fracture (LHF) following medial opening-wedge distal tibial tuberosity osteotomy (DTO). Methods: A total of 68 patients who underwent DTO were stratified into non-LHF and post-operative onset LHF groups. The groups were compared in terms of radiographic parameters, including the hip–knee–ankle (HKA) angle, and were clinically evaluated using the Knee Society Score (KSS) and 2011KSS. Multiple logistic regression analysis was performed to identify risk factors for post-operative onset LHF. Results: The non-LHF and post-operative onset LHF groups included 53 and 15 patients, respectively. The post-operative HKA angle was significantly smaller (valgus) in the post-operative onset LHF group than in the non-LHF group (P ​= ​0.005). Knee and function scores were significantly lower in the post-operative onset LHF group than the non-LHF group at 6 months (P ​= ​0.002 for each comparison). All 2011KSS subscores were significantly lower in the post-operative onset LHF group than the non-LHF group at 6 months (P ​= ​0.001, 0.010, 0.013, and 0.013, respectively). Post-operative HKA angle was a risk factor for post-operative onset LHF (odds ratio ​= ​0.589, 95% confidence interval 0.392–0.886; P ​= ​0.011). Conclusions: Post-operative weight bearing may be delayed to prevent post-operative onset LHF, especially in patients with post-operative large valgus knee alignment.