Contribution of Musculoskeletal Ultrasound in the Diagnosis of Seronegative Rheumatoid Arthritis

Objective This is a study to investigate the value of musculoskeletal ultrasound for the early diagnosis of seronegative rheumatoid arthritis (SNRA); and to study the relationship between anti‐cyclic citrullinated peptide antibody (anti‐CCP) and the occurrence of bone erosion in rheumatoid arthritis (RA) detected by ultrasound. Methods A total of 101 patients with RA or osteoarthritis (OA) admitted to the First Affiliated Hospital of Anhui Medical University from July 2022 to December 2023 were selected and divided into the SNRA group, the SPRA group, and the OA group. The patients' metacarpophalangeal joints, proximal interphalangeal joints, distal interphalangeal joints, and wrist joints of both hands were ultrasonically examined separately, and the extensor tendon, flexor tendon, synovium, joint surface, joint cavity, and bone surface were observed. Results The differences in the detection of joint effusion, bone erosion, and joint space narrowing were not statistically significant between SNRA group and OA group ( P > .05), the differences in the detection of synovitis and tenosynovitis were statistically significant ( P < .05). The mean levels of synovial hyperplasia grade and synovial blood flow grade between SNRA group and OA group were significantly different ( P < .05). The differences in synovitis, tenosynovitis, joint effusion, and joint space narrowing were not statistically significant between SNRA and SPRA groups ( P > .05), and the differences in bone erosion were statistically significant ( P < .05). The mean levels of synovial hyperplasia grade and synovial blood flow grade between SNRA group and SPRA group were significantly different ( P < .05). Logistic regression analysis showed that anti‐CCP antibody was an influential factor for bone erosion in RA patients ( P < .05). The ROC curve was plotted, and the optimal cut‐off value of anti‐CCP antibody was 356.5 U/mL, at which time the AUC was 0.716, the sensitivity of diagnosing bone erosion was 0.714, the specificity was 0.694, and the Yoden index was 0.408. Conclusion In summary, ultrasound is helpful for the early diagnosis of SNRA by evaluating the condition of joints, synovium, and tendon sheath, and when anti‐CCP antibodies are positive, ultrasound is more likely to detect bone erosion. Ultrasound examination combined with anti‐CCP antibody can further observe the joint lesions.