This study aims to compare the efficacy, accuracy, and functional outcomes of two different surgical stabilization techniques for medial opening wedge high tibial osteotomy (HTO) in patients with varus deformity and medial compartment osteoarthritis. Patients will be prospectively randomized into two groups: Group 1 (Plate Fixation) will receive acute (single-stage) correction and stabilization with a medial HTO locking plate. Group 2 (HTO External Fixator) will receive stabilization using a self-adjusting HTO external fixator, followed by gradual correction (hemicallotasis/distraction) starting 7 days post-operatively. The study will evaluate radiological correction, functional improvement (using the Oxford Knee Score), and complication rates over a 12-month follow-up period.