Clinical and radiographic evaluation of modular knee replacement

Ninety-five modular total knee replacements, 54 of them unicompartmental, have been reviewed. The average follow-up was three years. The major indication for operation was pain. A precise reoperative radiographic evaluation and a technique for a positioning the components are described. This had led to a significant improvement in the clinical and radiographic results in 67 out of 95 knees which were operated on. The modifications concern the orientation of the tibial cut, the placing of the femoral components and the correction of axial deviation. The main causes of the 13% of failures in our series were either errors in positioning the components or a preoperative diagnosis of rheumatoid arthritis. Unicompartmental replacement gave similar results in both valgus and varus knees, and the morbidity was lower than in the biocompartmental replacements. The best results were obtained in osteoarthritic knees in elderly patients and in posttraumatic osteoarthritis.