External Validity of a New Prediction Model for Patient Satisfaction After Total Knee Arthroplasty

J Arthroplasty. 2019 Aug;34(8):1677-1681. doi: 10.1016/j.arth.2019.04.021. Epub 2019 Apr 13.

Abstract

Background: The ability to identify patients at risk of dissatisfaction after total knee arthroplasty (TKA) remains elusive. This study's purpose was to determine the external validity of a recently published prediction model for patient satisfaction (PMPS) with the hypothesis that it would achieve similar predictive success in our study sample.

Methods: A 10-question PMPS statistically derived from 5 patient-reported outcome questionnaires was tested for external validity in this prospective cohort investigation. The PMPS incorporates gender, age, stiffness, noise, and pain catastrophizing, with a score of 20 or greater predictive of satisfaction. As in the original study, to determine satisfaction the 2011 Knee Society Score (KSS) satisfaction subscale was collected at 3 months postoperatively. Two hundred seventy-four patients were administered the PMPS preoperatively, and 145 patients completed the KSS at 3 months postoperatively (53.0% response rate; 59% female; age, 64.9; body mass index, 32.5). A Bland-Altman analysis to assess agreement was performed.

Results: One hundred thirty-three patients (91.7%) were satisfied and 12 (8.3%) were dissatisfied based on their postoperative KSS. The mean difference between the PMPS and KSS was 3.6 ± 8, but with a 95% prediction interval of -15.3 to 22.1 signifying almost no correlation. The PMPS did not predict any of the 12 dissatisfied patients postoperatively, and falsely predicted 5 patients to be dissatisfied of which 4 actually had a maximum postoperative KSS of 40.

Conclusion: A previously published, internally validated 10-question PMPS was unable to predict satisfaction after TKA in our external study sample. This study emphasizes the difficulty of developing a simple, but robust questionnaire that consistently predicts patient satisfaction after TKA.

Keywords: dissatisfaction; outcomes; prediction; satisfaction; total knee arthroplasty.

Publication types

  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Arthritis, Rheumatoid / psychology
  • Arthritis, Rheumatoid / surgery
  • Arthroplasty, Replacement, Knee*
  • Body Mass Index
  • Female
  • Humans
  • Knee Joint / surgery
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / psychology*
  • Osteoarthritis, Knee / surgery
  • Pain / surgery
  • Pain Management
  • Pain Perception
  • Patient Reported Outcome Measures*
  • Patient Satisfaction / statistics & numerical data*
  • Postoperative Period
  • Prospective Studies
  • Reproducibility of Results
  • Severity of Illness Index
  • Surveys and Questionnaires