THE INFLUENCE OF PATIENT FACTORS ON CONTEMPORARY TOTAL KNEE REPLACEMENT OUTCOMES AT FIVE TO TEN- YEAR FOLLOW-UP

Abstract

The purpose of this study was to assess the influence of patient factors on six to eleven year TKR outcomes.

Three hundred and sixty-five consecutive patients (436 Genesis II TKR’s) were prospectively analyzed according to gender, diagnosis, body mass index, pre-operative deformity, pre-operative range of motion and implant type.

The Kaplan-Meier survivorship for the TKR patients was 98% ±.8% at nine years. Large and significant improvement in pre-operative health related quality of life (HRQL) outcomes (KSCR, WOMAC and SF-12) were noted Female patients demonstrated significantly worse pre-operative and post-operative KSCR, WOMAC and SF-12 scores but similar change scores and decreased post-operative range of motion compared to their male counterparts. Patients with rheumatoid arthritis had significantly inferior pre-operative and post-operative HRQL indices, but similar change scores. Rheumatoid patients achieved greater post-operative range of motion than patients with osteoarthritis. Patients with a body mass index > 30 had significantly less pre-operative and one year range of motion, but beyond two years follow-up health-related quality of life indices and range of motion were similar to other BMI categories. Pre-operative deformity did not affect patient outcome. Pre-operative range of motion had a significant effect on post-operative range of motion. Comparable outcomes were achieved with both posterior cruciate ligament preserving and sacrificing total knee replacements; however, the posterior cruciate ligament sacrificing implants had significantly greater postoperative range of motion.

With a contemporary total knee replacement with 98% Kaplan-Meier survivorship at nine years, male gender, a diagnosis of osteoarthritis and a good pre-operative range of motion were indicators of improved post-operative outcomes. Change scores of health-related outcomes are a better indicator of efficacy than simply noting pre- and post-operative scores.