Background Musculoskeletal involvement is major complication for patients with systemic sclerosis (SSc). Many radiographic abnormalities are observed, especially in hands, however, the detailed prevalence and the association with clinical features is still unclear.
Objectives To clarify the characteristics of radiographic findings in hand X-ray and their association with clinical features in SSc.
Methods Japanese SSc patients without rheumatoid arthritis who visit our hospital from 2011 to 2015 were included. Two directional hand X-ray was taken to evaluate joint and soft-tissue changes. Clinical and serological parameters were collected retrospectively from their medical records. The prevalence of abnormal findings in X-ray was examined, and the associations with clinical features, SSc subtypes and autoantibodies were analyzed.
Results Sixty four patients including 16 diffuse cutaneous (dc) SSc and 49 limited cutaneous (lc) SSc were enrolled. The mean age was 66.7 years (range 31–88years), 87.5% were female and the mean disease duration was 13.9 years (range 1–37 years). Thirty four patients (53.1%) were positive for anticentromere antibody, 21 (32.8%) for anti-Scl-70 antibody, and 3 (4.7%) for anti-RNA polymerase III antibody. Fifteen (24.6%) were positive for rheumatoid factor (RF), and 1 (1.6%) for anti-cyclic citullinated peptide (CCP) antibody. Finding of hand X-ray showed acroosteolysis in 18.4%, erosive hand osteoarthritis in 15.4%, flexion contracture in 13.8%, and calcinosis in 10.8%. Acroosteolysis was significantly associated with digital tip ulcer (p<0.01), digital pitting scar (p<0.01), interstitial lung disease (p<0.05), gastrointestinal involvement (p<0.05), and longer disease duration (p<0.01). Flexion contracture also showed the association with digital tip ulcer, digital pitting scar, and gastrointestinal involvement (p<0.01, p<0.01, and p<0.05, respectively). While acroosteolysis and flexion contracture were more frequent in dcSSc than lcSSc (43.8% vs 10.4%, p<0.01 and 31.3% vs 8.3%, p<0.05, respectively), erosive osteoarthritis was observed only in lcSSc (dcSSc 0% vs lcSSc 20.4%, p>0.05). Calcinosis and erosive osteoarthritis were not related with any other clinical features including age, sex, and disease duration. Assessing the relation between X-ray findings and autoantibody, acroosterolysis were associated with positivity for anti Scl-70 (P<0.05,), and flexion contracture with anti-RNA polymerase III (P<0.05), but no association was found between X-ray findings and RF/anti-CCP antibody positivity.
Conclusions Various abnormal findings in hand X-ray were observed in patients with SSc. Of these, acroosteolysis was most prevalent. Both acroosteolysis and flexion contracture were associated with peripheral circulatory disturbance and the distinct characteristics of dcSSc, whereas erosive osteoarthritis was observed only in lcSSc. These results suggest that the difference of X-ray findings reflects the underlying pathogenesis of each patient with SSc.
Disclosure of Interest None declared