Efficacy and safety of ultrasound-guided local injections of etanercept into entheses of ankylosing spondylitis patients with refractory Achilles enthesitis.

OBJECTIVES: Enthesitis is one of the most common and specific manifestations of ankylosing spondylitis (AS). However, the treatment of enthesitis is still a challenge for rheumatologist so far, especially to those AS patients with serious enthesitis. This study aimed to evaluate the efficacy and safety of ultrasound (US)-guided local injection of etanercept into entheses of AS patients with refractory Achilles enthesitis.
METHODS: Twelve AS patients with severe unilateral refractory Achilles enthesitis were enrolled. Among them, 5 patients received US-guided local injection of etanercept and the other 7 received betamethasone. BASDAI, BASFI, VAS of the affected heel, the percentage of ASAS20 responders, CRP, ESR and any adverse events were recorded at baseline, 2, 4, 8 and 12 weeks after the treatment. US was also used to evaluate the corresponding entheses at baseline and every follow-up visit.
RESULTS: The BASDAI, BASFI, VAS of the affected heel, CRP, ESR, the percentage of ASAS20 responders and the regional blood flow signals detected by colour Doppler were all improved in both the etanercept group and the betamethasone group, at each follow-up visit compared to the baseline data (p<0.05). There were no significant differences in the improvements of any of the above parameters between the two groups (p>0.05). In addition, there were no adverse events from the etanercept group, except for the mild acid bilges feeling during the injection procedure, while 1 patient from the betamethasone group developed mild local atrophoderma since the week 4 follow-up visit and the atrophoderma kept stable at the 2 subsequent visits.
CONCLUSIONS: US-guided local injection of etanercept might be a highly effective, safe and well tolerated treatment for Achilles enthesitis in patients with AS.