SAT0357 PREVALENCE OF RADIOGRAPHIC ENTHESEAL LESIONS AT THE HIP AND PELVIC REGION IN PATIENTS WITH ANKYLOSING SPONDYLITIS
Authors: Freke Wink, Thomas Diemel, Suzanne Arends, Anneke Spoorenberg
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Enthesitis is one of the features of ankylosing spondylitis (AS). High prevalence of structural and inflammatory ultrasound lesions of peripheral entheses are found in AS patients. Furthermore, plain radiographs provide good imaging of peripheral enthesopathy at well-defined skeletal sites1. There are several entheseal sites at the pelvis and hip region, but little is known about the presence of structural entheseal anomalies at these sites in AS. <h3>Objectives:</h3> Our aim was to investigate the prevalence of radiographic entheseal lesions at the hip and pelvic region in patients with AS. <h3>Methods:</h3> The present analysis was performed in 214 patients from the Groningen Leeuwarden Axial SpA (GLAS) cohort study, who were included between November 2004 and December 2010 and had available anteroposterior (AP) pelvis radiographs at baseline. All patients fulfilled the modified New York criteria for AS. Radiographs were scored by two trained readers blinded for patient characteristics and treatment. Anomalies with absolute agreement were reported. The entheseal sites scored were: trochanter major, trochanter minor, os ischium, crista iliaca, both left and right side and symphysis pubis. The following 3 anomalies were scored: cortical irregularities/erosions, calcifications and enthesophytes. <h3>Results:</h3> Of the 214 patients, 148 (69%) were male, mean age was 42.5 ± 11.6, 171 (80%) were HLA-B27 positive and median symptom duration was 16 years (IQR 8-24). Reader agreement on the entheseal lesions was moderate to excellent with Cohen's kappa's between 0.474 and 0.882. 122 patients (51%) showed enthesopathy with 309 lesions in total. The most prevalent lesions were irregularities/erosions (n=220; 71%), followed by enthesophytes (n=71; 23%) and calcifications (n=16; 5%). Most lesions were found at the os ischii (n=168; 54%), followed by the tuberculum majus (n=42; 14%), crista iliaca (n=40; 13%), tuberculum minus (n=30; 10%) and symphysis pubis (n=29; 9%). <h3>Conclusion:</h3> In this cohort of established AS patients, a high prevalence of radiographic entheseal lesions at the hip and pelvic region was found. Irregularities and erosions were most frequently found, especially at os ischium. These new findings concerning structural entheseal lesions at the pelvis and hip region contributes to the knowledge of entheseal involvement in AS. <h3>References</h3> [1] Voudouris KP, Sidiropoulos P, Vounotripidis P, Arvanitakis M. Enthesial fibrocartilage – bone interaction: a radiographic study of selected sites of nonsynovial peripheral enthesopathy. J Musculoskelet Neuronal Interact. 2003 Mar;3(1):89-100. <h3>Disclosure of Interests:</h3> Freke Wink Consultant for: Abbvie, Janssen, Thomas Diemel: None declared, Suzanne Arends Grant/research support from: Grant/research support from Pfizer, Anneke Spoorenberg Grant/research support from: Received unrestricted grants from Pfizer, Novartis and Abbvie pharmaceuticals. They had no influence in design and conduct of the study., Consultant for: Abbvie, Pfizer, MSD, UCB, and Novartis