[Unicondylar replacement of the knee joint.]

Twenty-nine unicondylar replacements of the knee joint (UKR) of St. Georg type were implanted in 27 patients at the Orthopaedic Clinic IPVZ in the period between 1985-1994. The average age in case of females was 73 years, in case of men 71 years. The most frequent indication was osteoarthritis of the knee joint of varus type. Two patients (7 %) had to be reoperated on for aseptic loosening of the tibial component, on average 5,5 years after the surgery. Revision surgery for breaking of femoral component was performed in five cases, on average 6 years after the primary implantation. The authores evaluated 16 patients with UKR still in situ. In 8 patients the prosthesis is entirely painless, in 10 joints operated on the radiograph showed a developed femoropatelar osteoarthritis, osteoarthritic changes of the opposite compartment in 2 of them and a radioluscent line up to 1 mm in 3 cases. Despite a high frequency of late complications the authors consider UKR for an alternative to high supratubercular osteotomy of tibia in older patients, for a suitable method of the treatment of osteochondritis dissecans and Ahlbäck disease of the knee joint. The success of this operation is conditioned by a perfect surgical technique and implant of suitable design. Key words: replacement of the knee joint, aseptic loosening, fatique failure of material.