Secondary operations after knee joint replacement.

In 254 knee joint arthroplasties performed during the period between 1972 and 1977, secondary operations were done in 31 knee joints, a frequency of 12%. In the rheumatoid group the frequency was 6%, in those with osteoarthritis, 18%. Loosening was the indication for reoperation in 14 cases and infection in seven. Hinge prostheses required reoperations more often than the other types (Geomedic, St. Georg). Obesity and a previous operation on the same knee increased the risk of complication leading to reoperation. Reoperation involved exchange of prosthesis in 17 patients, arthrodeses in three, irrigation drain in three, femur amputation in one, and minor intervention in the remaining seven. The results of the reoperations were classified as good in 13 cases, fair in 12 and bad in six.