Shoulder Pain in Rheumatoid Arthritis: Ultrasound Findings and Clinical Correlations

Aims Shoulder pain is a common yet often overlooked manifestation of rheumatoid arthritis (RA). The prevalence and causes of shoulder pain in RA patients are not well-characterized, and imaging techniques, such as high-resolution musculoskeletal ultrasound (HRUS), have been underutilized in understanding its etiological profile. This study aims to evaluate the prevalence and explore underlying structural abnormalities (assessed via HRUS) and clinical characteristics of shoulder pain in patients with RA. Materials and methods An observational, cross-sectional study was conducted involving 208 RA patients. Patients were assessed using HRUS and clinical evaluations, including the Shoulder Pain and Disability Index (SPADI). Statistical analysis The study used descriptive statistics to summarize demographic and clinical data, calculated prevalence estimates for ultrasonography findings, and conducted group comparisons using one-way analysis of variance (ANOVA), Tukey's test, Kruskal-Wallis test, and Fisher's exact test. Results Shoulder pain was present in 105 out of 208 RA patients, yielding a prevalence of 50.48%. HRUS findings revealed that subacromial-subdeltoid (SASD) bursitis was the most common abnormality (50/105, 47.6%), followed by subcoracoid bursitis (35/105, 33.3%) and synovitis (16/105, 15.2%). Notably, 36 (34.3%) of patients exhibited no detectable HRUS abnormalities despite reporting pain. A significant association was found between seropositivity and shoulder pain, with 93.33% of patients with shoulder pain being seropositive. Conclusion Shoulder pain is prevalent among RA patients and is frequently associated with bursitis and synovitis, although it can occur without detectable HRUS abnormalities. Structural abnormalities correlate with increased pain severity and functional disability.