Using the UCI (University of California at Irvine) total knee prosthesis, an arthroplasty was performed in ninety-seven patients (121 knees) from 1972 through 1977. I examined eighty of these patients (100 knees) at three to eight years after the operation and it was necessary to either perform or recommend further surgery in twenty-five of them (twenty-seven knees). These results were designated as failures. The knees in valgus angulation that failed typically did so within the first year because of medical instability and patellar dislocation. The knees in varus angulation that failed typically did so one to six years after operation because of loosening of the tibial component. When failure became established, each knee was found to have reverted to its preoperative angular deformity, indicating that deforming factors were still operative. I suspect that ligament imbalance may have contributed to many of these failures. The surface area and stiffness of the 5.0 and 7.5-millimeter-thick tibial components of the original UCI prosthesis were not sufficient to prevent loosening and subsidence. Constraint between the tibial and femoral components was not sufficient to prevent subluxation or dislocation if soft-tissue release was needed for correction of deformity. Prompted by this experience, total knee arthroplasty using the UCI device has been discontinued at the Ochsner Medical Institutions.