Unicompartmental knee arthroplasty. Eight- to 12-year follow-up evaluation with survivorship analysis

One hundred consecutive unicondylar knee arthroplasties were reviewed after eight to 12 years of follow-up evaluation. Eighteen patients (19 knees) had died, four patients (four knees) were lost to follow-up evaluation, and 13 patients (13 knees) had revision. Survivorship analysis revealed 90% survivorship of the prostheses at nine years, 85% at ten years, and 82% at 11 years. Sixty-four knees in 51 patients were studied clinically and roentgenographically at final follow-up study. Of these, 87% had no significant pain. The average knee flexion was 115 degrees. Anatomic knee alignment averaged 3 degrees of valgus for the knees with preoperative varus alignment and 8 degrees of valgus for knees with preoperative valgus alignment. Fifteen percent of these elderly patients (mean age, 80 years) used a cane outdoors, but only 8% because of their knee. Sixty percent had radiolucent lines at the tibial bone-cement interface, and these lines were incomplete in 96% of cases.