Can Met Expectations Moderate the Relationship Between Pain/Function and Satisfaction in Total Knee Arthroplasty?

BACKGROUND: Approximately 20% of patients are dissatisfied with their total knee arthroplasty (TKA) at 1-year post-surgery. Met expectations have been found by some to significantly predict satisfaction. The role of met expectations in determining patient satisfaction has not been exhaustively explored. The primary aim of this study is to evaluate if met expectations moderate the relationship between pain and function variables and satisfaction. METHODS: Patients who underwent primary TKA for osteoarthritis were included in the study (n = 304). Patient-reported outcomes at pre-surgery and 1-year post-surgery were collected. The Knee Society Score (KSS) satisfaction subscale was used as the dependent variable. Candidate independent variables included the following: demographics, KSS, Knee injury and Osteoarthritis Outcome Score (KOOS), 12-Item Short Form Health Survey (SF-12), Hospital Anxiety and Depression Scale, Pain Catastrophizing Scale, Self-Administered Comorbidity Questionnaire, and University of California Los Angeles activity score. Separate linear regression models were created to test interactions for KSS met expectations with pain and KSS met expectations with function. RESULTS: Significant predictors of satisfaction were KSS symptoms (pain), KOOS activities of daily living (function), KSS met expectations, KOOS pre-surgery activities of daily living, body mass index, and SF-12 general health. A significant interaction between met expectations and pain was found (P = .043) and the met expectations and function interaction approached significance (P = .086). For both interactions, as met expectations increased, pain and function predicted satisfaction less strongly. CONCLUSION: Met expectations were found to moderate the relationship between pain and satisfaction. There may be more value in improving pain for patients with low met expectations. LEVEL OF EVIDENCE: Level IV.

Predictors of met expectations two years after knee surgery.

INTRODUCTION: The purpose of this study is to determine which patient factors predict two-year postoperative met expectations in a cohort of patients undergoing knee surgery. Additionally, this study aims to measure the association between met expectations and postoperative outcomes. METHODS: 319 patients undergoing knee surgery at one institution were studied. Patients completed patient-reported outcome questionnaires prior to surgery and again two years postoperatively. Preoperative Expectations and postoperative Met Expectations were measured using the Musculoskeletal Outcomes and Data Evaluation Management System (MODEMS) Expectations domain. RESULTS: The mean Met Expectations score was significantly lower than the preoperative Expectations Score. Worse two-year Met Expectations were associated with older age, higher BMI, greater comorbidities, more previous surgeries, black race, unemployment, lower income, government insurance, Worker's Compensation, smoking, and no injury prior to surgery. Greater Met Expectations were correlated with better scores on all two-year outcome measures as well as greater improvement on most outcome measures. Race, insurance status, function, mental health, and knee pain were found to be independent predictors of Met Expectations. CONCLUSION: This study identified multiple patient factors and outcome measures that were associated with Met Expectations two years after knee surgery.