Differential involvement of synovial adipokines in pain and physical function in female patients with knee osteoarthritis. A cross-sectional study.

OBJECTIVE: Adipokines have been reported to play a role in the development, progression and severity of knee osteoarthritis but the influence of the different adipokines are not well known. The aim of this study was to evaluate the association between different synovial fluid adipokines with pain and disability knee osteoarthritis patients. METHODS: Cross-sectional study with systematic inclusion of 115 symptomatic primary knee osteoarthritis female patients with ultrasound-confirmed joint effusion. Age, physical exercise, symptoms duration and different anthropometric measurements were collected. Radiographic severity was evaluated according to Kellgren-Lawrence scale. Pain and disability were assessed by WOMAC-total, -pain, -function subscales and Knee injury and Osteoarthritis Outcome Score (KOOS) pain and function scales. Seven adipokines and three inflammatory markers were measured by ELISA in synovial fluid. Partial Correlation Coefficient (PCC) and corresponding 95% confidence interval were used as a measure of association. RESULTS: Leptin, osteopontin and inflammatory factors, especially TNF-alpha, were associated to pain and function. After adjustment for potential confounders including inflammatory factors and all adipokines, an association was found for adiponectin with pain (PCC 0.240 [0.012, 0.444]) and for resistin and visfatin with function (PCC 0.336 [0.117, 0.524] and -0.262 [-0.463, -0.036]). No other adipokines or inflammatory markers were statistically and independently associated. An association between physical exercise and pain and disability remained after adjustment, whereas an attenuation of the influence of anthropometric measurements was observed. CONCLUSIONS: Different patterns of association between synovial fluid adipokines were observed regarding pain and disability in knee osteoarthritis patients. Specifically, adiponectin was associated to pain while resistin and visfatin were mainly related to function.