The clinical application of musculoskeletal ultrasound in diagnosing palindromic rheumatism-related joint lesions: a retrospective case-control study using rheumatoid arthritis as controls

To explore the clinical application of musculoskeletal ultrasound (MSUS) in the diagnosis of joint lesions in palindromic rheumatism (PR). Thirty-two PR patients (PR group) treated at the Department of Rheumatology, Ningbo No. 6 Hospital between January 2020 and September 2024 were selected as the study subjects. In parallel, 32 hospitalized RA patients (RA group) admitted between January 2024 and September 2024 were included as controls. All patients underwent MSUS examination. A semi-quantitative (SQ) grading method was used to score synovial hypertrophy (SH), power Doppler (PD), tenosynovitis, subcutaneous soft tissue inflammation, bone erosion, and GLOESS. The incidence of ultrasound findings and SQ scores were compared between the two groups. Hand joint involvement was higher in the PR group than in the RA group, whereas knee joint involvement was higher in the RA group than in the PR group, with statistically significant differences (P < 0.05). There were no significant differences in the distribution of wrist, elbow, or foot/ankle joint involvement between the two groups. The detection rates of tenosynovitis and periarticular subcutaneous soft tissue inflammation were higher in the PR group than in the RA group (P < 0.05). Furthermore, the detection rates of SH, PD, and bone erosion were lower in the PR group than in the RA group (P < 0.05). The detection rate of joint effusion did not differ significantly between groups (P > 0.05). GLOESS, the total ultrasound SQ score, as well as SQ scores for SH, PD, bone erosion and soft tissue inflammation were significantly lower in the PR group than in the RA group (P < 0.05). In contrast, the tenosynovitis score was significantly higher in the PR group (P < 0.05). Conclusion Arthritis in PR patients mainly involves the small joints of the hands, with characteristic MSUS features. Semi-quantitative MSUS scoring can effectively evaluate arthritis in PR patients and appears valuable as a diagnostic tool for this condition.