Effects of different hinge positions and coronal correction angle on tibial rotation in uniplanar medial opening wedge high tibial osteotomy with three-dimensional tibial models

Abstract

Abstract Purpose: There is a lack of studies investigating the distal tibial rotation (DTR) during medial opening wedge high tibial osteotomy (MOWHTO). The purpose of the present study was to evaluate the impacts of different hinge positions in the sagittal and axial planes and coronal correction angle on the axial rotation of tibia in uniplanar MOWHTO with three-dimensional tibial models. Methods: Preoperative CT data from 30 knee joints in 30 patients who underwent surgery for varus malalignment of knee were included. 1 standard hinge position (0°), 6 axial planes (±5°, ±10°, ±15°), and 6 sagittal planes (±5°, ±10°, ±15°) hinge positions were defined and virtual osteotomy was performed. The correction angle of each model was generated using Fujisawa’s point. The correction angle, preoperative medial proximal tibial angle, and DTR were measured. Results: A significant linear correlation was observed between changes in hinge position in the sagittal plane and DTR. The changes in DTR were the smallest when the hinge position was at 5°, where internal or external rotation of the DTR may occur. When the front aspect of hinge axis rotated distally, DTR tended towards internal. Meanwhile, when the front aspect of hinge axis rotated proximally, DTR tended towards external. There were no correlations with every hinge axis position in the axial plane. There were linear correlations between the correction angle and DTR in varying degrees dependent on different hinge positions. Conclusions: Both hinge position and coronal correction angle resulted in tibial rotation in uniplanar MOWHTO. In the sagittal plane, every change in hinge position was significantly linearly correlated with tibial rotation. However, no linear correlations were observed between every hinge position change in the axial plane. In addition, there were linear correlations between the coronal correction angle and tibial rotation in varying degrees dependent on the different hinge positions.