Large Versus Small Opening Wedge High Tibial Osteotomies Performed With a Protective Wire Over the Lateral Hinge: Incidence of Lateral Hinge Fracture and Early Clinical Outcomes
Don Thong Siang Koh, Junwei Soong, William Yeo, Marcus Wei Ping Tan, Shao Jin Teo, Adrian J. Wilson, KH Lee
Abstract
Background: The incidence of lateral hinge fractures (LHFs) during medial opening wedge high tibial osteotomy (MOW-HTO) is unacceptably high, especially with distractions >10 mm. LHFs result in malunion, loss of correction, and recurrence of symptoms adversely affecting clinical outcomes. Purpose: (1) To investigate the incidence of LHF when a protective guide wire is utilized during MOW-HTO in small and large corrections and (2) to study the effect of correction size on early clinical outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective analysis was performed of 96 knees that underwent MOW-HTO between 2019 and 2020. A protective wire applied intraoperatively across the lateral hinge point before opening wedge distraction was performed for all patients. Patients were divided into 2 groups based on opening wedge sizes: group A (opening distraction <10 mm) and group B (opening distraction ≥10 mm). LHF and wound complications were recorded. Prospective Knee Score and Function Score (Knee Society), Oxford Knee Score, and Physical and Mental Component Summaries of the 36-Item Short Form Health Survey questionnaire were recorded preoperatively and at 6 months and 2 years after surgery. Results: Incidence of LHF was low in group A (n = 2; 6.1%) and group B (n = 3; 9.1%). A single case of intraoperative LHF was noted in each group, with each case resulting in a type 1 fracture. The incidence of postoperative fractures was comparable between groups (groups A vs B, n = 1 vs 2). At 6 months, clinical outcomes in group A were superior to those of group B (Knee Score, 85.7 ± 14.7 vs 73.1 ± 20.3, P = 0.028; Function Score, 73.5 ± 16.5 vs 63.1 ± 19.5, P = 0.047; Oxford Knee Score, 20.2 ± 4.7 vs 25.6 ± 8.5, P = 0.008; Physical Component Summary, 46.8 ± 8.1 vs 40.2 ± 10.9, P = 0.018). However, clinical outcomes were comparable at 2 years ( P > .05). Conclusion: A protective wire was associated with a low incidence of LHF, even in larger MOW-HTO corrections. Large corrections had poorer clinical outcomes as compared with small corrections at 6 months. However, clinical outcomes between groups were comparable at 2 years.