Inclusion Criteria:  Unicompartmental Knee Arthrosis Femoral condyles or medial tibial plate osteonecrosis Healthy anterior cruciate ligament, posterior cruciate ligament and collateral ligaments of the affected knee Post traumatic loss of joint configuration Moderate varism deformity Patients between 50 and 80 years old Patients able to undergo a 2-year follow up after surgery  Exclusion Criteria:  Bi or Tricompartmental arthrosis Unhealty anterior or posterior cruciate ligaments or collateral ligaments Patients with neuromuscolar, degenerative and joint-related conditions Patients younger than 50 Patients older than 80 Patients unable to undergo a 2-year follow up after surgery