The Mediating Effect of Psychological Flexibility in the Relationship Between Two‐Way Social Support and Rehabilitation Exercise Adherence in Patients With Total Knee Arthroplasty

ABSTRACT Objective This study aims to investigate the impact of two‐way social support on rehabilitation exercise compliance among patients undergoing total knee arthroplasty and examine psychological flexibility's mediating role. Design Cross‐sectional study. Methods A convenience sample of 266 total knee arthroplasty patients was recruited from the orthopaedic department of a tertiary hospital in Guiyang, Guizhou Province, between November 12, 2024, and March 20, 2025. Data were collected using standardised instruments, including a general demographic questionnaire, a brief two‐way social support scale, a simplified multidimensional psychological flexibility inventory, and a rehabilitation exercise adherence scale. Amos 29.0 software was used to construct a structural equation model of the mediating effect of psychological flexibility between two‐way social support and rehabilitation exercise compliance. Results Pearson correlation analysis revealed significant positive associations among two‐way social support, psychological flexibility, and rehabilitation exercise compliance ( = 0.538–0.730, < 0.001). Mediation analysis demonstrated that two‐way social support enhanced rehabilitation exercise compliance indirectly through increased psychological flexibility (effect size = 0.336, 95% [0.253–0.442], < 0.05), accounting for 53.0% of the total effect. Additionally, a significant direct effect of two‐way social support on rehabilitation exercise compliance was observed (effect size = 0.298, 95% [0.181–0.432], < 0.05). Conclusion Two‐way social support has a positive influence on rehabilitation exercise compliance in TKA patients, with psychological flexibility serving as a partial mediator. These findings suggest that healthcare professionals can improve patient compliance with rehabilitation protocols by fostering greater psychological flexibility.