Subclinical hip involvement in rheumatoid arthritis. An ultrasound assessment

Abstract

IntroductionHip joint involvement in rheumatoid arthritis has been related to disability and lower quality of life. Currently, not enough studies provide information for subclinical hip involvement. ObjectivesTo determine the prevalence of subclinical hip joint involvement in rheumatoid arthritis, characterizing it by ultrasound. Materials and methodsA descriptive cross-sectional study in rheumatoid arthritis patients with an established diagnosis of rheumatoid arthritis according to EULAR/ACR 2010 classification criteria, without hip pain or abnormalities during a clinical examination (subclinical group), this group was compared with a group of symptomatic patients with rheumatoid arthritis of the hip (pathological control group), and with healthy control individuals matched by age and body mass index. The presence of joint capsule distension, osteophytes, joint remodelling process, erosions, iliopsoas bursitis, and power Doppler signal was assessed. The images were interpreted by an experienced rheumatologist blinded to clinical and laboratory variables. Results234 hips were studied; 37 (31.6%) symptomatic hip patients, 40 (34.1%) asymptomatic hip patients and 40 (34.1%) healthy individuals. The prevalence of joint capsule distension was 20%, while symptomatic hip patients and healthy individuals had a prevalence of 48.6% and 15%, respectively. The asymptomatic group presented higher values for osteophytes and joint remodelling. ConclusionsUltrasound is a sensitive tool to identify subclinical hip joint synovitis in rheumatoid arthritis patients, reaffirming the value of ultrasound in preclinical diagnosis. The presence of erosions and iliopsoas bursitis was low; we observed no power Doppler signals nor significant associations between ultrasound findings with disease activity and laboratory test results.