Association of suprapatellar pouch effusion with knee pain and serum IL-6, IL-17, IL-23 in patients with knee osteoarthritis

Abstract

Objective To explore the association of suprapatellar pouch effusion with knee pain and serum levels of interleukin (IL)-6, IL-17, IL-23 in patients with knee osteoarthritis measured by magnetic resonance imaging (MRI). Methods 204 patients with knee osteoarthritis were enrolled into the study. Suprapatellar pouch effusion was measured by OSIRIS in both grade (0-3) and maximum area (cm2). Serum IL-6, IL-17, IL-23 were measured. Knee pain was assessed by Western Ontario and McMasters osteoarthritis index (WOMAC) questionnaire and Lequesne index. Characteristics of patients were recorded and body mass index (BMI) was calculated. Student t test or Chi-square test was used to compare means or proportions. Multivariable linear regression or logistic regression was used to determine risk factors (α=0.05). Results ① In the 204 patients [mean age (55±8) years, 86.3% were females], the prevalence of physiologic effusion(≤ 1) was 47.9% while moderate or larger (≥2) effusion was 52.1%.② The age, labour intensity, serum levels of uric acid (sUA) and Lequesne index of higher grade effusion group were higher (P<0.05) compared with lower grade effusion group. ③ Suprapatellar pouch effusion maximum area was positively correlated with age (r=0.208, P=0.006), BMI (r=0.171, P=0.027) and labour intensity (r=0.189, P=0.013).④ Adjusted for age, gender and BMI, the results of Logistic regression analysis showed that: suprapatellar pouch effusion grades were positively correlated with Lequesne index [OR=1.120, 95% CI(1.011, 1.241), P=0.029] and negatively correlated with IL-23 [OR=0.768, 95% CI (0.598, 0.986), P=0.038]. Suprapatellar pouch effusion was not independently associated with WOMAC index, IL-6 and IL-17. Conclusion The prevalence of suprapatellar pouch pathological effusion is 52.1% in knee osteoarthritis. Suprapatellar pouch effusions is positively correlated with knee pain (Lequesne index) and negatively correlated with IL-23. Key words: Osteoarthritis, knee; effusion; Knee pain; Interleukin-23