Description
Unintended secondary changes in posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSI), it is essential to reproduce the PTS and TTA as planned for simulation. This study aims to the factors causing unintended sagittal and axial alignment changes after MOWHTO. Axial hinge axis angle caused the difference in PTS between simulation and actual surgery. TTA change was caused by a combination of multiple factors, such as large correction angle and anterior osteotomy angle but mainly by the instability of the lateral cortical hinge.
