Early tibial component loosening of medial UKA after severe medial plateau SONK—report of three cases

Spontaneous osteonecrosis or subchondral bone insufficiency fracture of the knee is a frequent injury in elderly female patients. The medial femoral condyle followed by the medial plateau is the most prevalent sites. When its evolution after conservative treatment is not favorable, medial unicompartimental arthroplasty is a surgical option with good results. We report three cases of early tibial component loosening of medial unicompartimental arthroplasty that could be related to a severe subchondral bone insufficiency fracture of the tibial plateau. In these cases of severe involvement of the tibial plateau, a more careful evaluation would be recommended to choose between unicompartimental and total knee replacement to avoid this early loosening.