ABSTRACT
Objective:To evaluate the correlation of active inflammatory changes of the symphysis pubis on magnetic resonance imaging (MRI) scans with clinical factors in patients with axial spondyloarthritis.Methods:We retrospectively evaluated 112 patients with axial spondyloarthritis (ax-SpA) in our hospital from February 2014 to November 2020. Patients were divided into 4 groups: symphysis pubis + sacroiliac arthritis, symphysis pubis + non-sacroiliac arthritis, non-symphysis pubis + sacroiliac arthritis, and non symphysis pubis + non-sacroiliac arthritis group. Intra-group correlation coefficient ( ICC) was used to analyze the correlation between MRI active inflammation of the symphysis pubis and the sacroilioarthritis. Age, sex, symptom duration, smoking, body mass index, human leukocyte antigen (HLA)-B27 positive rate, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) among the four groups were compared by one-way analysis of variance (ANOVA) and Chi-square test. Results:The proportion of active inflammation of the symphysis pubis was 35.7% (40/112). There was no correlation between active inflammation of the symphysis pubis and sacroilioarthritis ( r=-0.06, P=0.559). Twenty-four patients of the 69 patients with sacroilioarthritis had active inflammation of the symphysis pubis, 16 patients of the 43 patients without sacroilioarthritis had active inflammation of the symphysis pubis. In patients without active inflammation of the sacroiliac joint, the CRP and ESR of the active inflammation of the symphysis pubis group was (49±60) mg/L, (40±19) mm/1 h, statistically higher than that of the non-active inflammation group (19±22) mg/L, (22±37) mm/1 h ( t=2.36, P=0.023; t=2.88, P=0.006). In patients who had active inflammation of the symphysis pubis, the symptom duration of the non-active inflammation of the sacroiliac joint, was (14±9) years, which was significantly longer than that of the active inflammation group (5±4) years ( t=4.07, P=0.001). Conclusion:There is no correlation between active inflammatory changes of the symphysis pubis and bone marrow edema of the sacroiliac joint. Therefore, in ax-SpA patients with inflammatory low back pain and/or hip/groin pain, and also with high levels of CRP, ESR, but no active inflammatory changes of the sacroiliac joint on MRI scans, active inflammation of the symphysis pubis should be considered.