TNF-α and sTNF-RII are associated with pain following hip fracture surgery in older adults

Objective. To explore whether plasma inflammatory mediators on postoperative day 3 (POD3) are associated with pain scores in older adults after hip fracture surgery. Design. Cross-sectional study. Setting. Mount Sinai Hospital, New York, New York. Subjects. Forty patients age 60 years or older who presented with acute hip fracture at Mount Sinai Hospital between November 2011 and April 2013. Methods. Plasma levels of six inflammatory mediators of the nuclear factor kappa B pathway were measured using blood collected on POD3. Selfreported pain scores (i.e., pain with resting, walking, and transferring) were assessed at baseline (prefracture) and on POD3. Linear regression models using log-transformed data were performed to determine associations between inflammatory mediators and postoperative pain. Results. Interleukin 18 (IL-18) was positively associated with POD3 resting pain score in the unadjusted model (b50.66, P50.03). Tumor necrosis factor a (TNF-a) and soluble TNF receptor II (sTNF-RII) were positively associated with POD3 resting pain score in the adjusted model (b50.99, P50.03, and b50.86, P50.04, respectively). Moreover, TNF-a was positively associated with POD3 walking pain score in the adjusted model (b51.59, P50.05). Pain with transferring was not associated with these inflammatory mediators. Conclusions. These findings suggest that TNF-a and its receptors may influence pain following hip fracture. Further study of the TNF-a pathway may inform future clinical applications that monitor and treat pain in the vulnerable elderly who are unable to accurately report pain.