FIFTEEN YEAR FOLLOW-UP OF PRIMARY TOTAL KNEE REPLACEMENTS IN THE TRENT REGION

Abstract

Purpose: To evaluate the fifteen year survivorship of primary Total Knee Replacements in a single UK health region.

Methods: Since the beginning of 1990, and with the agreement of all consultant orthopaedic surgeons in the region, all primary total knee replacements (TKR) performed throughout Trent were recorded prospectively. At the time of operation the surgeon completes a questionnaire, which records demographic, medical and operative details for each patient and implant.

In this study we have traced all the patients, who had a primary total knee replacement between 1990 and 1992. We issued a validated, self administered questionnaire to all surviving patients, at a mean of fifteen years post arthroplasty. This questionnaire examines the patient’s level of expectation and satisfaction with their TKR, and also measures their quality of life (using EQ-5D and visual analogue score). Using a similar register, containing information of all revision TKR in the region, we have measured the survivorship of these primary TKR at 10 and 15 years.

Results: 4,665 primary TKR were performed on 4,448 patients. At fifteen year follow-up 1,408 patients were alive. The questionnaire response rate was 57.1% (n=912). Of our responders, 87.8% were satisfied with the result of their TKR at 15 years post-arthroplasty, and 82% felt their TKR had met their expectations.

Survivorship analysis revealed that 94.7% (+/−0.4%) of implants survive to 10 years, and 92.7% (+/−0.5%) to 15 years. Survivorship was significantly affected by gender of the patient, age at time of primary, and type of prosthesis used. Infection rate at 15 years was 0.9%.

Discussion: This is one of the first long term studies of primary TKR, which assesses survivorship of primary TKR beyond 10 years. This study shows that survivorship at 5 and 10 years compares favourably to the results of similar studies from other countries.