NONCEMENTED, POROUS INGROWTH KNEE PROSTHESIS - THE 3-YEAR TO 8-YEAR RESULTS

Objective. To determine the principal long-term problems encountered i n noncemented total knee replacement. Design: A cohort of 252 consecut ive cases of total knee replacement with no exclusions. Follow-up rang ed from 3 to 8 years. Setting. A university-affiliated institution spe cializing in orthopedic surgery. Participants: All 252 patients had ar thritis of the knee, mainly osteoarthritis. All agreed preoperatively to prolonged postoperative follow-up. Intervention: Noncemented total knee replacement with the Tricon M prosthesis, which has a metal-backe d patella. Main Outcome Measures: The Hospital for Special Surgery rat ing system for clinical results and the radiologic results, including reasons for revision surgery. Results: Thirty-five prostheses were rev ised: 11 prostheses because of patellar wear only; in 1 3 prostheses t he tibial component (mainly a 6-mm unit) and patella were revised beca use of wear; 6 prostheses were revised for sepsis, 4 for reflex sympat hetic dystrophy and 1 only for sinkage of the tibial component. Of the remaining 217 prostheses, 88% scored good or excellent, 6% fair and 6 % poor. Conclusions: The single most common cause of failure was polye thylene wear. This was associated with the metal backing of the patell a and the use of thin, polyethylene tibial components.