A statistical evaluation of polycentric total knee arthroplasties.

Four hundred nineteen knees in 299 patients were examined preoperatively and at two years after polycentric total knee surgery. One hundred forty-three knees were in 109 patients with osteoarthritis. Two hundred seventy-six knees were in 190 patients with rheumatoid arthritis. Pain decreased significantly, use of aids decreased significantly, and distance walked increased significantly in both groups. Rheumatoid patients did not fare as well as osteoarthritics in the use of aids and distance walked. Osteoarthritic knees had proportionately more implant settling, implant loosening and reoperations than did rheumatoid arthritic knees.