Unicompartmental Arthroplasty for Osteoarthritis of the Knee Using the Ceramic YMCK Model

Summary

The femoral component of the Ceramic YMCK Unicom Knee is made of stainless steel with two stems, and the tibial component of alumina ceramics with two stems. Unicompartmental arthroplasty with the YMCK model was performed on 57 knees (55 medial, 2 lateral) of 47 patients (7 men, 40 women) aged 59–83 years (average 71). The follow-up period ranged from 2 to 11 years (average 3.9). In 55 knees with preoprative medial compartment osteoarthritis the average femorotibial angle (standing) was 185° ± 6.5° before surgery. The malalignment was satisfactorily corrected and the angle was 174° ± 5.5° after replacements. The relief of pain was marked and the average Japanese Orthopaedic Association (JOA) Knee score was 51.5 ± 9.1 before surgery and 82.1 ± 11.3 after. Forty-six knees were judged as excellent or good according to the Hospital for Special Surgery (HSS) criteria postoperatively. We had one case with infection, treated successfully, and one case with breakage of the tibial component. There were four cases with metallosis, two of which were revised. There was no significant difference between the preoperative and postoperative arc of motion of the knee, but flexion contracture was improved significantly.