Combined with proximal (high) tibial osteotomy) and anterior cruciate ligament (ACL) reconstruction procedure is one of the surgical treatment modalities in patients with knee joint instability due to insufficiency of ACL accompanied by varus malalignment leading to medial compartment osteoarthritis. Main objectives of combined surgical approach in such cases are to reconstruct joint stability, prevent the progression to end-stage degenerative disease, and correct malalignment of the lower extremity. Patient selection, preoperative planning, and appropriate surgical technique are the key factors for higher success rates of the treatment. Combined surgical approach, especially in young and/or active individuals, not only provides improvement in functional clinical scores but also prevents progression of osteoarthritis and thus, need for joint replacement surgery.