Abstract
A cornerstone in the treatment of osteoarthritis in young patients is the evaluation and correction of the leg axis. The combination of a joint injury (meniscus, cartilage, ligament) and an axis deviation inevitably, depending on its extent and the patient's comorbidities such as obesity, leads to progressive osteoarthritis of the knee after a few years. In addition to the precise deformity analysis for osteotomy planning, it is important to know the normal ranges of the corresponding angles and to define a target value for axis correction. Reflecting the repertoire of different osteotomy options around the knee (open vs. closed, tibial vs. femoral, medial vs. lateral), the side effects in relation to patellofemoral maltracking, ligamentary balancing and leg length should then be assessed. Especially with regard to possible (and probable) prosthetic operations at some time in the future of young patients, new bony deformities or ligamentous insufficiencies, which potentially arise from overcorrection, must be avoided.