Problems and complications of knee endoprosthesis from the point of view of clinicians

Despite improvements in component design, instruments, and operative techni que, there remains a significant complication and failure rate in total kne e arthroplasty (TKA). Revision TKA accounts for every tenth operation in TK A. From lune 1991 to June 1994, 209 TKAs (182 patients) were performed. Of these, 73% were uncemented, 11.2% cemented, and 15.8% hybrid. The patella w as resurfaced in 96% with a cemented polyethylene or an uncemented metal-ba cked 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% n o local postoperative complications. Overall, 42 revisions (41 patients) we re performed during the 7-year follow-up. Revision surgery was necessary be cause of aseptic loosening (8.1%), polyethylene wear (4,8%), complications of the extensor mechanism (2.4%), traumatic periprosthetic fractures or kne e luxation (1.4%), and septic loosening (3.3%). Further improvements of pol yethylene will reduce polyethylene wear. Uncemented fixation of this prosth esis can only be recommended with hydroxyapatite coating.