Comparison of torsional changes in the tibia following a lateral closed or medial open wedge high tibial osteotomy

Objective: The aim of this study is to evaluate, by computed tomography (CT), whether different torsional changes occur in the tibia following a lateral closed wedge high tibial osteotomy (CWHTO) versus a medial open wedge high tibial osteotomy (OWHTO) procedure. It was hypothesized that the distal fragment of the tibia would show greater internal rotation after CWHTO. Methods: Thirty knees from 25 patients who underwent HTO were enrolled. Fifteen knees of 14 patients who underwent CWHTO and 15 knees of 11 patients who received OWHTO were match-paired. CT scans were taken before and three weeks after surgery. Rotational changes in the distal fragment of the tibia were assessed by measuring the tibial torsion angle (TTA). Results: The mean TTA in the CWHTO group pre-operatively and postoperatively was + 23.9° ± 7.8° and + 18.2° ± 7.0°, respectively. Internal rotation of the distal fragment of the tibia after CWHTO was − 5.7 ± 3.3° (P < 0.001). In the OWHTO group, the mean TTA pre-operatively and postoperatively was + 27.9° ± 6.9° and + 26.8 ± 7.7°, respectively, with no significant change in torsion observed (P > 0.05). Conclusions: The distal fragment of the tibia rotated internally after CWHTO but not after OWHTO. Level of evidence: Level III: case–control study.