The lateral compartment arthrosis of the knee is not frequent and huge well tolerated. The ethiology in the most cases in constitutional or secondary to displasy or trauma. We need appreciated the possibility to do corrective osteotomy before total arthroplasty in young patients with non severe degree of disease. The biomechanics is the base line of this possibility and the aim is to obtain an articular line in a horizontal position. It is the reason why the distal femoral osteotomy is the election site for it. In rare situations, like malunion of proximal tibial fracture (external tibial plateau) or light degrees of osteoarthrosis, the high proximal tibial osteotomy is indicated. Finally, technique, results and long-term problems on the knee before a total arthroplasty of the knee are exposed.

The lateral compartment arthrosis of the knee is not frequent and huge well tolerated. The ethiology in the most cases in constitutional or secondary to displasy or trauma. We need appreciated the possibility to do corrective osteotomy before total arthroplasty in young patients with non severe degree of disease. The biomechanics is the base line of this possibility and the aim is to obtain an articular line in a horizontal position. It is the reason why the distal femoral osteotomy is the election site for it. In rare situations, like malunion of proximal tibial fracture (external tibial plateau) or light degrees of osteoarthrosis, the high proximal tibial osteotomy is indicated. Finally, technique, results and long-term problems on the knee before a total arthroplasty of the knee are exposed.