THE ROLE OF PAIN AND FUNCTION IN DETERMINING PATIENT SATISFACTION FOLLOWING TOTAL KNEE ARTHROPLASTY: ANALYSIS OF DATA FROM THE NATIONAL JOINT REGISTRY (NJR)

Abstract

Purpose: To examine how patients viewed the outcome of their joint replacement at least one year post surgery. Emphasis was placed on investigating the relative influence of ongoing pain and functional limitation on patient satisfaction.

Method: Questionnaire based assessment of the Oxford Knee Score (OKS), patient satisfaction, and need for reoperation in a group of 10,000 patients who had undergone primary unilateral knee replacement between April and December 2003. Questionnaires were linked to the NJR database to provide data on background demographics, clinical parameters and intraoperative surgical information for each patient.

Data was analysed to investigate the relationship between the OKS, satisfaction rate and the background factors. Multivariable logistic regression was performed to establish which factors influenced patient satisfaction.

Results: 87.4% patients returned questionnaires. Overall 81.8% indicated they were satisfied with their knee replacement, with 7.0% unsatisfied and 11.2% unsure. The mean OKS varied dependent upon patients’ satisfaction (satisfied=22.04 (S.D 7.87), unsatisfied=41.70 (S.D 8.32), unsure=35.17 (S.D 8.24)). These differences were statistically significant (p< 0.001).

Regression modelling showed that patients with higher scores relating to the pain and function elements of the OKS had lower levels of satisfaction (p< 0.001) and that ongoing pain was a stronger predictor of lower levels of satisfaction. Other predictors of lower levels of satisfaction included female gender (p< 0.05), a primary diagnosis of osteoarthritis (p=0.02) and unicondylar replacement (p=0.002). Differences in satisfaction rate were also observed dependent upon age and ASA grade

609 patients (7.4%) had undergone further surgery and 1476 patients (17.9%) indicated another procedure was planned. Both the OKS and satisfaction rates were significantly better in patients who had not suffered complications.

Conclusion: This study highlights a number of clinically important factors that influence patient satisfaction following knee replacement. This information could be used when planning surgery to counsel patients and help form realistic expectations of the anticipated postoperative result.