Medial compartment osteoarthritis remains a clinical challenge for the orthopedic surgeon. Accurate preoperative planning is an integral part of management. MCOA with genu varum is not a single condition but a family of related deformities. One single technique may not be appropriate for all the permutations. An individualized approach is necessary to address the many facets of this complex disorder. Treatment must begin with recognition of all of these facets through careful history and physical examination and radiographic evaluation and through preoperative planning of the location of the deformity (femur, tibia, or knee joint), level of angulation, magnitude of the deformity, and plane of the angulation. One can then formulate a treatment plan to address the problems identified. Surgeons should not become rigid in their choice of method or device, but also consider its appropriateness to address the problems to be corrected. Because the patient seeks to prolong the life of the knee before joint replacement, a comprehensive approach achieving as accurate a correction as possible should be associated with the best possible outcome. In total knee replacement, the important emphasis has been on achieving correct bony alignment and soft-tissue balance. With osteotomy, the emphasis has been on bony alignment. However, soft-tissue balance should also be considered an important element in preserving the knee in osteotomy surgery.