Role of ultrasonography in diagnosis of peripheral entheseal involvement in patients with spondyloarthritis

Objective To compare the ultrasonography(US) and clinical examination in detection of peripheral enthesopathy in patients with spondyloarthritis (SpA). Methods Enthesis at symphysis pubis, bilateral sternoclavicular joint, and lower extremities(quadriceps tendon, proximal patellar ligament, distal patellar ligament, Achilles tendon and plantar aponeurosis) were detected in SpA patients by clinical and ultrasonographic examination. The patients were divided into clinical entheseal involvement group and none clinical entheseal involvement group according to the findings in clinical examination. Results Thirty-six SpA patients were enrolled in this study. Of the 466 attaching point lesions, 156(33.48%) were detected by US and 45(9.66%) were detected by clinical examination (P=0.000). Of the detected attaching point lesions, those at the distal patellar ligament, symphysis pubis, and Achilles tendon accounted for 75%, 64.71%, and 51.34%, respectively. US showed that the tendon was thicker and the bone erosion was severer in clinical entheseal involvement than in none entheseal involvement group (P< 0.05). Of the enthesis in lower extremities, bursitis was the most common lesion, accounting for 64%. Conclusion US can detect more enthesopathy at distal patellar ligament, sternoclavicular joint and symphysis pubis, except for distal Achille tendon than clinical examination.