Correlations among clinical, radiographic, and sonographic scores for enthesitis in ankylosing spondylitis

To look for correlations among clinical, radiographic, and sonographic scores for enthesitis in patients with ankylosing spondylitis (AS).

Prospective study of 60 patients meeting modified New York criteria for AS. The clinical evaluation relied on the BASDAI, BASFI, and ASQoL and on a visual analog scale (VAS) for entheseal pain, as well as on two specific enthesitis indices, the Maastricht Ankylosing Spondylitis Enthesitis Score (MASES) and the Spondyloarthritis Research Consortium of Canada Enthesitis Index (SPARCC). Radiographs and ultrasound scans were taken of five entheses on both sides (patellar insertion of the quadriceps tendon, proximal and distal insertions of the patellar tendon, and calcaneal insertions of the Achilles tendon and superficial plantar fascia). Ultrasound scans were obtained using a Philips HD 11™ machine with a high-frequency linear probe.

We studied 48 men and 12 women with a mean age of 36±11 years. The radiographic score correlated with the VAS pain score, BASDAI, and BASFI. The sonographic score for acute enthesitis correlated only with the MASES, and the sonographic score for chronic enthesitis correlated with none of the clinical scores. The Doppler score correlated with the VAS pain score, BASDAI, BASFI, and ASQoL. The overall sonographic score correlated with the MASES and SPARCC.

Good correlations were found between the clinical and sonographic scores for enthesitis. The radiographic score seemed correlated with the general AS parameters rather than with the clinical scores. Larger studies are needed to better define the role for radiographs and sonography of the entheses in the diagnosis of AS and follow-up of treated AS patients.