Pain Self-Efficacy Mediates the Relationship Between Pain Catastrophizing and Physical Function in People With Knee Osteoarthritis.

OBJECTIVE: To examine the associations between pain catastrophizing, pain self-efficacy, and physical function among individuals with chronic knee osteoarthritis. DESIGN: Cross-sectional observational study. METHODS: Data were collected from patients using a survey at routine visits to orthopedic providers. The participants (n = 104) were people with knee osteoarthritis (62.5% female), a mean age of 65 years (range: 29-91), and a mean body mass index of 31.86 ± 9.05 kg/m2. We estimated a regression-based mediation (PROCESS Model 4; 10,000 bootstrap samples) to test whether pain self-efficacy statistically mediated the association between pain catastrophizing and physical function. RESULTS: The total effect of pain catastrophizing on physical function was statistically significant. Pain catastrophizing had a significant direct effect on physical function after controlling for covariates. We observed a significant indirect effect of pain catastrophizing through pain self-efficacy, suggesting that the relationship between pain catastrophizing and physical function was partially mediated by pain self-efficacy. CONCLUSION: The observed pattern was consistent with individuals reporting lower pain self-efficacy also reporting higher pain catastrophizing and lower physical function. JOSPT Open 2026;4(2):215-222. Epub 21 January 2026. doi:10.2519/josptopen.2026.0168.