The relationship between central sensitization and activity limitation in patients with knee osteoarthritis:The mediating role of pain catastrophizing.

BACKGROUND

In patients with knee osteoarthritis, the most distressing symptom is activity limitation which exacerbates the global burden of the disease. Studies have shown that central sensitization has a negative effect on activity capabilities in patients with knee osteoarthritis. However, limited knowledge exists regarding the underlying mechanisms. Therefore, this study aimed to explore the mediating effect of pain catastrophizing on central sensitization and activity limitation among knee osteoarthritis patients.

OBJECTIVES

To explore the association between central sensitization and activity limitation by modelling three dimensions of pain catastrophizing as mediators among patients with knee osteoarthritis.

DESIGN

This is a cross-sectional study.

METHODS

A total of 392 patients were surveyed using the general demographic questionnaire, Animated Activity Questionnaire, Pain Catastrophizing Scale, and Central Sensitization Inventory. Multiple linear regression was used to determine covariates included in the mediating model. The mediating effect was tested using the SPSS PROCESS.

RESULTS

Age, duration of KOA, and K-L grade were included as covariates. The mediating model revealed that central sensitization had a direct effect on activity limitation (c' = -0.166; 95 % CI -0.271, -0.064). The relationship between central sensitization and activity limitation was primarily mediated by two indirect pathways: (1) rumination (a1b1 = -0.095; 95 % CI -0.176, -0.017) and (2) helplessness (a2b2 = -0.074; 95 % CI -0.137, -0.009). The indirect effect of the magnification dimension on activity limitation was not statistically significant (a3b3 = 0.002; 95 % CI -0.051, 0.054).

CONCLUSIONS

The study reveals rumination and helplessness in pain catastrophizing mainly mediate the relationship between central sensitization and activity limitation.