This study provides strong evidence that high tibial osteotomy (HTO) is effective in restoring knee alignment and improving functional biomechanics in patients with medial knee osteoarthritis and varus malalignment. In a prospective randomized case-control design involving 49 patients, those who underwent HTO (Surgical Group) showed a significant correction of the tibiofemoral angle (from 8.3 ± 3.3° to 0.9 ± 2.4°, p < 0.001), achieving values comparable to healthy controls.

Kinematic improvements included full restoration of knee and ankle adduction during walking, stair ascent, and descent, with statistically significant changes in at least 60% of the gait cycle (p < 0.05). Additionally, knee adduction and rotation moments were significantly reduced, with some patients displaying even lower-than-normal knee adduction moments during walking—suggesting potential overcorrection.

Despite these improvements, no significant changes were observed in walking speed or stride length, and residual alterations in pelvic obliquity and ankle flexion persisted. In contrast, the Conservative Group (non-surgical treatment) showed no biomechanical improvements at follow-up.

Overall, the study confirms the biomechanical effectiveness of HTO in correcting malalignment and improving joint function, while also identifying remaining compensatory patterns that may require targeted post-operative rehabilitation.