Reinforcement K-wires reduce the risk of tibial plateau and lateral cortex fractures during open wedge high tibial osteotomy: a prospective comparative cohort study

BACKGROUND: Open wedge high tibial osteotomy (OWHTO) may be complicated by iatrogenic fractures of the tibial plateau or lateral cortex, potentially compromising osteotomy stability. Reinforcement with intra-operative Kirschner wire (K-wire) has been proposed to mitigate this risk, but robust clinical evidence is limited. This study aimed to evaluate whether intra-operative reinforcement wires decrease the incidence of iatrogenic fractures during OWHTO and to assess their impact on clinical and radiological outcomes. METHODS: A prospective multi-centre comparative cohort study was conducted between March 2023 and March 2024, including 68 patients (72 initially enrolled) with medial knee compartment osteoarthritis and genu varum undergoing OWHTO who met predefined radiological and clinical criteria. Patients were allocated to a reinforcement group (Group A, n = 34; OWHTO with subchondral and lateral hinge K-wire reinforcement) and a control group (Group B, n = 34; OWHTO without reinforcement). Outcomes included intra-operative iatrogenic tibial plateau and lateral cortex fractures, weight-bearing milestones, radiographic parameters (medial proximal tibial angle (MPTA), mechanical axis deviation (MAD), posterior tibial slope), Lysholm knee scores at serial follow-up, and complications. RESULTS: Baseline demographics, comorbidities, and most intraoperative variables (excluding iatrogenic fractures) did not differ significantly between the reinforcement (Group A) and non-reinforcement (Group B) groups. No iatrogenic fractures of the tibial plateau or lateral cortex occurred in Group A, whereas 9 of 34 patients (26.5%) in Group B sustained such fractures (three each of Takeuchi types 1-3), with 6 of these 9 requiring additional lateral plating (P = 0.002). Patients in Group A achieved partial weight-bearing significantly earlier than those in Group B (P = 0.014), whereas Lysholm scores showed no significant differences between groups across all follow-up periods. Both groups exhibited comparable improvements MPTA, MAD, posterior tibial slope, and final Lysholm scores. Rates of wound complications and iliac crest bone graft harvest were similar between groups. CONCLUSION: Intraoperative reinforcement of the tibial plateau and lateral cortex with subchondral and lateral hinge K-wires effectively reduced the risk of iatrogenic fractures in OWHTO and is associated with improved early functional recovery without adversely affecting alignment, union, or complication rates. These findings support the incorporation of K-wire reinforcement as a simple, reproducible adjunct to enhance the safety of OWHTO in appropriately selected patients.