Survivorship of AGC knee replacement in juvenile chronic arthritis: 13-year follow-up of 77 knees.

This study analyzed the survivorship and results of 77 knee replacements in 52 patients with juvenile chronic arthritis using the nonconstrained Anatomically Graduated Components (AGC; Biomet, Warsaw, IN) prosthesis design. Patients were operated on between the years 1985 and 1995. The mean duration of the general disease was 24 years (range, 10-56 years), and the mean age of the patients at the time of surgery was 33 years (range, 16-64 years). Bone-grafts were installed into 15 knees, custom-made components were used in 5 knees, and cemented fixation in 4 knees. The patella was resurfaced in 23 knees. Clinical follow-up examinations were conducted 3 months, 1 year, 4 years, and 8 years postoperatively. An interview was arranged at the end of 1998, 3 to 13 years after surgery; 2 patients were not reached, and 2 died during the follow-up. Fifty-five of 73 (75%) knees were subjectively excellent, 18 (25%) were fair, and none was poor. Radiolucent lines of 1.0 to 1.5 mm were found under 14 tibial trays but not adjacent to femoral components. No deep infections were detected. One knee was revised 4 years after the implantation. The overall survival was 99% (95% confidence interval, 92-100) at 5 years. We consider these results excellent in this demanding patient material. The nonconstrained AGC prosthesis with cementless fixation proved to be feasible in knee replacement in patients with juvenile chronic arthritis.