Large opening width and low serum 25-hydroxyvitamin D status are associated with inferior 12-month radiographic gap healing after medial open-wedge distal tibial tuberosity osteotomy.

Abstract

Evidence regarding factors associated with radiographic gap healing (GH) after medial open-wedge distal tibial tuberosity osteotomy (MOWDTO) remains limited. This study aimed to identify patient-related and surgical factors associated with radiographic GH after MOWDTO. This retrospective observational study included 189 patients who underwent MOWDTO between January 2020 and December 2023. GH was evaluated on anteroposterior radiographs at 3 and 12 months postoperatively. Multiple linear regression analyses were performed for GH rate at each time point, and logistic regression analysis was performed for delayed GH at 12 months, defined as GH < 50%. Additional analyses included treatment-era adjustment, categorical and season-adjusted analyses of serum 25-hydroxyvitamin D [25(OH)D], and a sensitivity analysis using a stricter threshold of delayed GH. The mean GH rate was 20.99 ± 9.44% at 3 months and 55.62 ± 19.89% at 12 months, and delayed GH at 12 months was observed in 72 of 189 patients (38.1%). At 3 months, older age and hinge fracture were independently associated with a lower GH rate. The apparent association between porous hydroxyapatite/collagen composite (HAp/Col) use and lower 3-month GH was attenuated and was no longer statistically significant after adjustment for treatment era. At 12 months, larger opening width was independently associated with a lower GH rate, whereas higher serum 25(OH)D concentration, porous HAp/Col use, and greater descending cut thickness were associated with a higher GH rate. In logistic regression analysis, larger opening width was associated with increased odds of delayed GH, whereas higher serum 25(OH)D concentration, porous HAp/Col use, and greater descending cut thickness were associated with lower odds of delayed GH. In the era-adjusted delayed-GH model, the association for porous HAp/Col use was attenuated and became borderline significant. No patient developed nonunion or required additional surgery during follow-up. Opening width, hinge fracture, descending cut thickness, porous HAp/Col use, and serum 25(OH)D level were associated with radiographic GH after MOWDTO, although the robustness of these associations differed across the additional analyses. Level III, Retrospective Cohort Study.