[Knee endoprosthesis: clinical aspects]

Despite improvements in component design, instruments, and operative technique, there remains a significant complication and failure rate in total knee arthroplasty (TKA). Revision TKA accounts for every tenth operation in TKA. From June 1991 to June 1994, 209 TKAs (182 patients) were performed. Of these, 73% were uncemented, 11.2% cemented, and 15.8% hybrid. The patella was resurfaced in 96% with a cemented polyethylene or an uncemented metal-backed patella component. Follow-up showed significant improvement in knee and function scores 1 and 5-7 years postoperatively. Of the patients, 77% showed no general and 80% no local postoperative complications. Overall, 42 revisions (41 patients) were performed during the 7-year follow-up. Revision surgery was necessary because of aseptic loosening (8.1%), polyethylene wear (4.8%), complications of the extensor mechanism (2.4%), traumatic periprosthetic fractures or knee luxation (1.4%), and septic loosening (3.3%). Further improvements of polyethylene will reduce polyethylene wear. Uncemented fixation of this prosthesis can only be recommended with hydroxyapatite coating.