Unicompartmental knee arthroplasty. A prospective consecutive series followed for six to 11 years

A consecutive prospective series of 102 knees (90 patients) had unicompartmental knee arthroplasty (St. Georg "sledge") between 1973 and 1979 for gonarthrosis, Stages 2-4. Total clinical and roentgenographical evaluation was undertaken after 5-11 years (mean, 8.1 years) and included all 75 surviving patients. Fully comparable results were encountered in the 15 patients who died during the observation period. There were no early revisions but five late revisions; two due to loosening, one late infection, one instability, and one intractable pain. Complete loosening occurred in four patients (4%). Functional score (Hospital for Special Surgery method) averaged 77 points (preoperative, 43) with no tendency of deterioration with time. Loss of initially achieved alignment was generally associated with bone resorption around the tibial component. Minor arthrotic changes of the non-operated compartment occurred in 4% of the cases.