Functional outcome of GUEPAR hinge knee arthroplasty evaluated with ARAMIS

Forty-nine patients with 66 GUEPAR offset knee hinge replacements followed for one to 5 1/2 years were evaluated using the American Rheumatism Association Medical Information System (ARAMIS). The series included 37 female and 12 male patients whose average age was 69 years. Postoperative pain in 92% of patients decreased by an average of three grades. Maximum walking ability improved in 43% and worsened in 14%. Fewer walking aids were used by 51% of patients, whereas 18% needed increased support. Stair-climbing ability improved in 42% and worsened in 10%. Thirty-six additional functions were evaluated. Standing, housework and shopping abilities improved significantly. Range of motion improved from 87 degrees to 103 degrees and flexion contractures decreased by 11%. Varus and valgus abnormalities were almost uniformly corrected. Complications included a 23% rate of patella dislocation or subluxation. Extensor lag occurred in 26% of patients postoperatively, averaging 11 degrees. Deep infection occurred in six knees (9.1%); five were successfully treated for infection and the sixth was successfully treated by arthrodesis. Silastic bumpers broke in all cases and were associated in some instances with significant pain and effusion. Probable loosening has occurred in only one component.