While it is clear that opening-wedge high tibial osteotomy (HTO) changes alignment in the coronal plane, which is its objective, it is not clear how this procedure affects knee kinematics through the range of joint motion and in other planes. Our research question was: how does opening-wedge HTO change three-dimensional tibiofemoral and patellofemoral kinematics in loaded flexion in patients with varus deformity? Three-dimensional kinematics were assessed over 0-60° of loaded flexion using a MR method before and after opening-wedge HTO in a cohort of 14 knees of 13 male subjects. At 6 and 12 months post-op, opening-wedge HTO caused increased tibial anterior translation (mean 2.6 mm, p < 0.001), decreased patellar proximal translation (mean -2.2 mm, p < 0.001), decreased patellar spin (mean -1.4°, p < 0.05), increased patellar tilt (mean 2.2°, p < 0.05), and changed three other parameters. Mean WOMAC score decreased significantly (p < 0.001) from 49.6 (SD 16.4) preoperatively to 28.2 (SD 16.6) at 6 months and 22.5 (SD 14.4) at 12 months. The three-dimensional kinematic changes found may be important in explaining inconsistency in clinical outcomes, and suggest that measures in addition to coronal plane alignment should be considered.Applied Science, Faculty ofMedicine, Faculty ofNon UBCMechanical Engineering, Department ofOrthopaedic Surgery, Department ofReviewedFacultyOthe
