Ultrasound-guided retro-calcaneal bursa corticosteroid injection for refractory Achilles tendinitis in patients with seronegative spondyloarthropathy: efficacy and follow-up study.

Ultrasound (US)-guided corticosteroid injection has been shown to be safe and effective for varied causes of plantar fasciitis; however, its use for Achilles tendinitis is controversial. We studied the efficacy and changes in US findings at Achilles enthesitis after corticosteroid injection in patients with spondyloarthropathy (SpA). Patients with SpA with symptomatic Achilles enthesitis, refractory to 6 weeks of full-dose NSAIDs, were offered US-guided local corticosteroid injection. Injected entheses were examined by US (both B mode and power Doppler) at baseline and 6 weeks after injection. Standard OMERACT definitions were used to define enthesitis. Achilles tendon thickness >5.29 mm, 2 cm proximal to insertion in long axis, was considered thickened. Twenty-seven symptomatic Achilles tendons (in 18 patients) were injected with 20 mg methylprednisolone under US guidance baseline, and 6-week follow-up US features were compared. All patients reported improvement in pain (VAS) in the affected tendon after injection (p < 0.0001). Simultaneously, improvement in local inflammatory changes were noted, in the form of significant reduction in tendon thickness (p < 0.0001), vascularity (p < 0.0001), peritendinous oedema (p = 0.001), bursitis and bursal vascularity (p < 0.001 and < 0.0001, respectively). There was no change in bone erosions and enthesophyte. None of the patients had tendon rupture or other injection-related complications at 6 weeks of follow-up. US-guided local corticosteroid injection is an effective and safe modality for refractory Achilles enthesitis in patients with SpA and leads to reversion of acute changes at entheseal site.