Effect of tibial rotation after uniplane medial open-wedge high tibial osteotomy in genu varum patients: An observational study

The change in axial tibial rotation after uniplane medial open-wedge high tibial osteotomy (uniplane OWHTO) and its relevant influence factor is not known. Therefore, the aim of this study was to evaluate the change in axial tibial rotation after uniplane OWHTO, and the factors affecting tibia rotational change were analyzed. Between January 2022 and April 2022, the study was retrospectively conducted on genu varum patients who underwent uniplane OWHTO. In the weight-bearing anteroposterior long leg view, the hip-knee-ankle angle and medial proximal tibial angle (MPTA) were evaluated. The posterior tibial slope were measured from the lateral view. A CT scan of the knee joint was performed to evaluate the distal tibial rotation angle (TRA), femorotibial rotation angle and tibial tuberosity-trochlear groove distance. In addition, the foot morphology was assessed by the ankle deformity angle and ankle rotation angle using an angle measuring instrument. All parameters were measured preoperatively and 14 days after surgery. The mean change in hip-knee-ankle, MPTA was 10.5°±2.9°, 8.8°±2.6°. The mean preoperative and postoperative TRA were 25.1°±6.9° and 22.2°±6.2° respectively (P = .007). Thus, the mean ∆TRA was −3.0°±3.4° (IR) with a range of −9.6° to +2.8° after surgery. No significant differences were found in the femorotibial rotation angle and tibial tuberosity-trochlear groove distance before and after surgery (P > .05). The postoperative ankle rotation angle and ankle deformity angle changed significantly compared with preoperative values (P < .001). In the multiple regression analysis, ∆MPTA was the only predictor of distal tibial rotation (β = 0.667, P = .003). The current study confirms an unintended internal rotation in the distal tibia following uniplane MOWHTO and the rotation in the distal tibia was influenced by the opening width. Surgeron should keep in mind to avoid the osteotomy complication leading to excessive rotation change during surgery.