In a first-of-its-kind study led by clinical investigator Rocco Giordano, researchers shed light on the complex interplay between inflammation and chronic postoperative pain following knee arthroplasty. Published in the prestigious European Journal of Pharmacology, the study suggests that low-grade inflammation may persist in a subset of patients experiencing high levels of pain, catastrophizing, and functional impairment even 5 years after the surgery.

Chronic postoperative pain remains a significant challenge for patients undergoing knee arthroplasty, yet there is a lack of research on the specific inflammatory factors contributing to long-term pain complications. Seeking to address this knowledge gap, the exploratory study embarked on a two-fold mission: first, to assess a comprehensive panel of inflammatory markers 5 years’ post-knee surgery among patients with different pain intensity; and second, to investigate the possible links between these markers and clinical pain intensity, cognitive, and functional outcomes.

After collecting the plasma samples of 76 knee patients (43 females and 33 males), 44 inflammatory markers were examined. The visual analogue scale (VAS) was used to assess the pain intensity, whereas the functional and cognitive aspects were assessed by the Oxford knee score (OKS) and pain catastrophizing scale (PCS), respectively. Based on these scores/parameters, the knee patients were divided into high or low groups and their association with inflammatory markers was studied.

As per Pearson's correlations, 12 biomarkers correlated with VAS, 4 with PCS and 3 with OKS (statistical significance, p < 0.05). Furthermore, the study revealed distinct alterations in marker expressions among patients experiencing high chronic postoperative pain, high levels of catastrophizing, and poor functional scores compared to their counterparts with lower symptomatology.

Four markers differed in patients with high chronic postoperative pain compared to those with low pain, 3 markers varied in individuals with high versus low catastrophizing tendencies, and 3 markers showed discrepancies in patients with poor functional scores.