6 TO 10-YEAR EXPERIENCE USING COUNTERSUNK METAL-BACKED PATELLAS

Three hundred two consecutive cementless total knee arthroplasties (Na tural Knee, Intermedics Orthopedics, Inc., Austin, TX) were performed using a metal-backed, porous coated patellar component. Fifty-nine pat ients died and 31 were lost to follow-up evaluation, resulting in 212 knees available for evaluation at 6 to 10 years. The mean follow-up pe riod was 91 months. The mean modified Hospital for Special Surgery tot al knee score improved from 58 before surgery to 98 at the most recent follow-up visit. Mean patellar translation and tilt were 2.75 mm and 3.5 degrees, respectively. There were no patellar lucencies nor loosen ing. Eleven patients (5%) underwent revision of the patellar component . Overall patellar survivorship was 96%. Comparatively good results ca n be achieved with the use of a metal-backed patellar component if com ponent design, surgical technique, and patellar alignment are properly addressed.