Abstract:

Objective To explore the ultrasonographic features of enthesopathy in lower limbs in spondyloarthropathy (SPA) and rheumatoid arthritis (RA). Methods The ultrasonographic features of enthesopathy in both lower limbs of  43 patients with SPA (SPA group) were retrospectively analysed, and were compared with those of 40 patients with RA (RA group)  and 30 healthy controls (HC group). The diagnosis of enthesopathy was made based on the abnormal findings such as increased tendon thickness, bursa fluid, intratendinous calcifications, bony spur and bony erosion, and vascularization. Results Abnormal ultrasonographic findings of tendon were observed in 93% of SPA group,85% of RA group and 23% of HC group, respectively. There was no significant difference in the detection rates of enthesopathy by ultrasonography between SPA group and RA group (P>0.05), while both were significantly higher than that of HC group (P<0.05). The number of tendons with bursitis in SPA group was smaller than that in RA group（8.6％ vs 14.0％，P<0.05）, and  bursitis in SPA group was less severe than that in RA group [（3.92±1.79 ）mm vs（5.97±2.63）mm, P<0.05], while there was no significant difference in the number of tendons with the other abnormal ultrasonographic findings between SPA group and RA group（P>0.05）. The major abnormalities in HC group were calcification and bony spur in distal part of achilles tendon insertion, and no bursa fluid or vascularization was found. Conclusion The ultrasonographic features of  enthesopathy is highly sensitive with lower specificity. The severity of bursitis may help to discriminate the disease cause.

Key words: spondyloarthropathy, rheumatoid arthritis, enthesopathy, ultrasonography