Noncemented, porous ingrowth knee prosthesis: the 3- to 8-year results

Abstract

Objective: To determine the principal long-term problems encountered in noncemented total knee replacement.

Design: A cohort of 252 consecutive cases of total knee replacement with no exclusions. Follow-up ranged from 3 to 8 years.

Setting: A university-affiliated institution specializing in orthopedic surgery.

Participants: All 252 patients had arthritis 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-backed patella.

Main outcome measures: The Hospital for Special Surgery rating system for clinical results and the radiologic results, including reasons for revision surgery.

Results: Thirty-five prostheses were revised: 11 prostheses because of patellar wear only; in 13 prostheses the tibial component (mainly a 6-mm unit) and patella were revised because of wear; 6 prostheses were revised for sepsis, 4 for reflex sympathetic 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 polyethylene wear. This was associated with the metal backing of the patella and the use of thin, polyethylene tibial components.