POS1271 PREVALENCE OF JOINT EFFUSION, HYPERPERFUSION AND ENTHESITIS IN YOUNG HEALTHY INDIVIDUALS

Abstract

Background:The European League Against Rheumatism (EULAR) recommends using ultrasound (US) in patients with rheumatoid arthritis and psoriatic arthritis in diagnosis (1). In addition, US examination is crucial for detecting enthesitis in the above mentioned rheumatic diseases. However, abnormal findings on US may also occur in healthy individuals as indicated by recent studies focusing on small joints like metacarpophalangeal joint, metatarsophalangeal joint or the elbow. (2,3)Ultrasound assessment of large joints in healthy individuals has not been extensively studied so far, causing a lack of information concerning normal values in musculoskeletal US examination.Objectives:The purpose of this study was to determine the prevalence of joint effusion, hyperperfusion of the synovia and enthesitis in large and medium-sized joints of healthy individuals.Methods:Ultrasound assessment of shoulder, elbow, wrist, hip, knee and ankle joints as well as corresponding entheseal sites including the Achilles tendon and the plantar aponeurosis was performed in healthy individuals below the age of 30 years. Additionally, participants filled out a survey on their physical activity level, underwent a bioelectrical impedance analysis (BIA) and conducted a supervised weight training to determine their training volume. Prevalence of US findings was calculated, and a binary logistic regression model was applied to determine the association between the present findings and sex, age, handedness, hours of sports activity per week, BMI, amount of skeletal muscle mass (SMM) or training volume of strength training.Results:We included 51 healthy individuals with a mean age of 23.7 years, 52.9% were female with a mean BMI of 22.5 kg/m2. Ultrasound examination detected joint effusion in one joint in 25.5% (n=13), 29.4% (n=15) showed effusion in two of twelve examined joints. Joint effusion in three, four and five joints was detected in 9.8% (n=5), 3.9% (n=2) and 3.9% (n=2) of the cases, respectively. In 27.5% (n=14) of the individuals no joint effusion was observed. The most frequently affected joint was the elbow joint. Synovial hyperperfusion was not detected in any participant. Enthesitis was observed in one, two and three examined entheseal sites in 19.5% (n=10), 5.9% (n=3) and 2% (n=1), respectively. In 72% (n=37) of the examined individuals no pathology of the entheseal sites was found. Hyperperfusion presented to be the most frequent pathology observed in enthesitis (23%), followed by calcification (6%).Binary logistic regression model demonstrated a significant association between reported hours of sports activity per week and the prevalence of effusion in the knee (p = 0.017). The odds of joint effusion in the knee increased with the hours of sports activity by 34.1% (Exp(B)= 1.341, 95%-CI(1.054, 1.705)). Additionally, the odds of enthesitis in any entheseal site increased with BMI (p= 0.015, Exp(B) = 1.407, 95%-CI(1.068, 1.852).Binary logistic regression model did not show any significant association between sex, age, handedness, amount of SMM or training volume of strength training and the prevalence of joint effusion or enthesis pathology in the examined participants.Conclusion:Joint effusion in large and mid-sized joints as well as enthesitis are not only detected in patients with rheumatic diseases but also in healthy individuals. Hours of sports activity and BMI have a significant association with the findings and should be considered during ultrasound examination.