The semiquantitative assessment of metacarpal head cartilage damage in rheumatoid arthritis via ultrahigh frequency ultrasound.

Background: Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease characterized by proliferative synovitis. Articular cartilage damage is an early stage of joint damage and is difficult to repair as the disease progresses, exerting a severely negative impact on the quality of life of patients with RA. In early RA, the vulnerable areas include the metacarpophalangeal (MCP) joint, proximal interphalangeal (PIP) joint, and the wrist. Metacarpal head (MH) cartilage damage appears to be prevalent in the second and third fingers on the semiquantitative assessment of MCP 2-5 cartilage in patients with RA, but the specific portions of cartilage damaged in each of these sections has not been examined. Moreover, few studies have compared the efficacy of the two scoring methods in assessing RA cartilage via ultrahigh frequency ultrasound (UHFUS). The aim of this study was to investigate the common sites of MH cartilage damage in patients with RA and compare various semiquantitative scoring methods for evaluating MH cartilage in patients with RA using UHFUS. Methods: In this cross-sectional study, a total of 2,200 dorsal cartilages of the MH in 110 patients with RA and 110 healthy controls were included and scanned in both the transverse and longitudinal sections via UHFUS. Cartilage damage in the MH was assessed using the three- and five-grade semiquantitative scoring systems. The Cochran Q test was used to evaluate the various damage locations, and the chi-square test was employed to compare the positive detection rates of the two scoring techniques. The correlation between semiquantitative evaluation results and clinical and laboratory indicators was determined via Spearman correlation analysis. Results: Rate of impairment on the five-grade scoring system was higher than that on the three-grade scoring system. The rate of impairment on the five-grade scoring system of the transverse and longitudinal sections was 24.18% and 17.00%, respectively. The rate of impairment on three-grade scoring system of the transverse and longitudinal sections was 18.18% and 13.18%, respectively. Additionally, cartilage damage was more common in the transverse sections than in the longitudinal sections, with the most commonly afflicted regions being the ulnar side of the transverse sections and the distal side of the longitudinal sections. The rate of cartilage damage on the ulnar and distal side was 7.20% and 6.30%, respectively. Cartilage damage was weakly positively correlated with age, duration of disease, weight, body mass index (BMI), C-reactive protein (CRP), and Disease Activity Score 28 (DAS28) using CRP. Conclusions: The five-grade semiquantitative scoring system for UHFUS demonstrated reliability for detecting MH cartilage damage in RA. The MCP cartilage of the ulnar and distal sides are particularly susceptible to injury.