Ultrasound Evaluation of the Entheses in Daily Clinical Practice during Tumor Necrosis Factor-α Blocking Therapy in Patients with Ankylosing Spondylitis.

OBJECTIVE: To assess structural and inflammatory ultrasound (US) lesions of entheses in ankylosing spondylitis (AS) patients with active disease and to evaluate inflammatory lesions after 6 months of tumor necrosis factor (TNF-α) blocking therapy, in daily clinical practice.

METHODS: Consecutive patients with AS were clinically evaluated and underwent US examination of 9 bilateral entheses before and after 6 months of TNF-α blocking therapy. US examination included the following as inflammatory lesions: bone erosions/cortical irregularities, enthesophytes, calcifications as structural lesions; adjacent bursitis, effusion, increased tendon hypoechogenicity or thickness; and positive power Doppler (PD) signal.

RESULTS: At baseline, 105 (95%) of 111 included patients showed US abnormalities. Structural lesions were seen in 74 patients (67%) and inflammatory lesions in 88 (79%). Enthesophytes and positive PD signal were the most prevalent structural and inflammatory lesions, respectively. Most lesions were found at the lower extremities. Additionally, inflammatory lesions occurred at the lateral epicondyle of the elbow. Patients with structural lesions at baseline were significantly older, had longer disease duration, higher modified Stoke AS Spine score, and higher C-reactive protein. Individually, there was a great diversity in changes of inflammatory entheseal lesions during treatment, but on the group level no significant decrease was found.

CONCLUSION: This prospective observational cohort study in daily clinical practice shows a high prevalence of structural and inflammatory US lesions in AS patients with longstanding and active disease. Positive PD signal was the most common inflammatory feature. No significant change in inflammatory US lesions was found after 6 months of TNF-α blocking therapy.