Objective: to compare ultrasound (US) changes of the painful shoulder between patients with rheumatoid arthritis (RA) and patients with degenerative shoulder disease (DSD).
Patients and methods: Patients with painful shoulder (n=178) were divided according to clinical diagnosis made by rheumatologist: Group1-77 patients with RA, Group2-101 patients with DSD. US changes were evaluated by linear transducer 7.5 MHz for: long head biceps tendon-LHB, supraspinatus tendon-SSP, infraspinatus tendon-ISP, subscapularis tendon-SSC, subacromial/subdeltoid bursa-SA/SD-B, glenohumeral joint effusion-JE, bone cartilage-BC and humeral erosions-HE. The ultrasound examiner was blinded for clinical findings, diagnosis and patient identification.
Results: Frequent pathological changes were found in: SSP tendon (84.4% RA and 71.7% DSD), LHB tendon (81,8% RA and 69,3% DSD), ISP tendon (58.4% RA and 56.4% DSD) and SSC tendon (49,4% RA and 46,5% DSD) (p=0.045 p=0.058 p=0.951 and p=0.710 respectively). Evaluating changes separately, statistical differences were noted in: LHB tenosynovitis, SSP tendon rupture (three times more in RA patients), ISP tendon rupture (five times more in RA patients), as well as in glenohumeral JE, BC reduction and HE (p=0,019 p=0.001 p=0.005 p=0.000 p=0.003 and p=0.007, respectively). LHB tendon pathology (tendinopathy, subluxatio and rupture), SSC tendinopathy, global SSP and ISP tendinopathy as well as bursitis of SA/SD did not show statistical difference between the patient groups. Using logistic regression model, the following set of items: glenohumeral JE, BC reduction and HE has shown to be distinctive between RA and DSD group.
Conclusion: Ultrasound detected different frequencies of LHB tenosynovitis, SSP and ISP tendon ruptures, glenohumeral JE, BC reduction and HE in RA and DSD patients comparisons. Combination of glenohumeral joint effusion, bone cartilage reduction and humeral erosions was able to identify patients with RA in a population of patients with painful shoulder disease with a moderately high degree of confidence.