Inflammatory predictors of ongoing pain 2 years following knee replacement surgery

The prevalence of unrelieved pain following total knee arthroplasty (TKA) is substantial.

We asked if cytokine markers of inflammation in preoperative serum or knee synovial fluid (SF) would predict pain 2 years following TKA.

Demographic data and functional outcomes were recorded at baseline and 2 years with the WOMAC index. Serum and SF tissue samples were collected at the time of surgery. Linear regression modeling was used to determine the relationship between SF/serum inflammatory markers and a lesser improvement in self reported pain at two years follow-up.

Of our 28 patient cohort, significant correlations between serum and SF levels were found for IL-1β (p < 0.002), MIP-1β (p < 0.001), adiponectin (p < 0.001) and leptin (p < 0.001). Adjusted analysis showed that greater SF concentrations of TNF-α, MMP-13 and IL-6 were independent predictors of less pain improvement at two years follow-up (p < 0.05).

Those patients, having ongoing pain despite no clinical or radiological cause, may have an inflammatory profile characterizing a predisposition to ongoing pain after TKA.

Prognosis study, Level 2.