"Hybrid" total knee arthroplasty with the Miller-Galante prosthesis. A prospective clinical and roentgenographic evaluation.

Twenty-nine "hybrid" Miller-Galante total knee arthroplasties, in 22 patients, were evaluated prospectively and according to the clinical and roentgenographic guidelines of The Knee Society. Selection of this technique, incorporating an uncemented, porous-ingrowth femoral component and a cemented tibial component, was based on patient age, medical condition, activity level, and intraoperative assessment of bone quality and ligament competency. The average age of the patients at the time of surgery was 71 years. The average preoperative Knee Society Knee Score was 32; average pain score was 14; and the average function score, 47. After an average follow-up interval of 28 months postsurgery (minimum, 24 months), the average Knee Society Knee Score was 93; the average pain score, 47; and the average function score, 79. Range of motion averaged 110 degrees. Only one knee, with persistent pain of obscure origin, rated an unsuccessful result. No arthroplasties were revised for any reason. Twenty-three knees had fluoroscopically guided roentgenograms to assess the bone-prosthesis and bone-cement interfaces. No significant or progressive radiolucencies were noted under any of the components. No apparent adverse bone remodeling was associated with the uncemented femoral component. The fluoroscopically guided roentgenograms were significantly more sensitive in detecting interface radiolucencies than plain ones. Clinical and roentgenographic evidence of component loosening were absent in all patients. Results of this study suggest that the hybrid fixation technique can reliably provide satisfactory pain relief and restoration of function in properly selected patients. Potential advantages of an uncemented femoral component include decreased operative time, reduction of polyethylene wear from cement debris, and avoidance of a possible adverse biologic response to polymethylmethacrylate.