Safety and efficacy of image-guided retrocalcaneal bursa corticosteroid injection for the treatment of retrocalcaneal bursitis

Objective: To determine the safety and efficacy of image-guided retrocalcaneal bursa corticosteroid injection for retrocalcaneal bursitis. Materials and methods: After IRB approval, all fluoroscopically guided and ultrasound-guided retrocalcaneal bursa injections (2013–2019) were retrospectively evaluated. Pre-procedure US and radiographs were scored by 2 blinded radiologists in consensus for Achilles tendinosis and retrocalcaneal bursitis (0–3 scale), Achilles enthesopathy (present/absent), and Haglund deformity (present/absent). Pre- and post-procedure pain scores (0–10 scale) evaluated short-term response at 1–4 weeks: excellent (7–10 point decline), good (4–6 point decline), fair (1–3 point decline), or no response. Paired t-test determined significance of short-term improvement. Kaplan-Meier method analyzed time to progression to surgery or complication at 6-month minimum follow-up. Logistic regression analysis evaluated for association between demographic and imaging variables and negative outcome. Results: Two hundred eighteen injections (181 female; mean 54.5 years) performed under ultrasonographic (157, 72%) or fluoroscopic (61, 28%) guidance were evaluated for complication and long-term outcomes. Injections with short-term follow-up (n = 62) yielded excellent or good response in 62.9% (p < 0.00001). Thirty patients (14%) had subsequent elective Achilles surgery. Bursal Doppler flow was associated with progression to surgery (p = 0.00042). No differences were identified in outcomes between US and fluoroscopic-guidance cohorts. Four Achilles ruptures (1.8%) were identified 15–59 days post-injection, each with immediately preceding acute injury. Conclusion: Image-guided retrocalcaneal bursa corticosteroid injection yields significant short-term decrease in pain score in majority (63%) of patients. Subsequent Achilles tendon rupture rate was 1.8%. Bursa Doppler flow was significantly correlated with progression to surgery and may represent a negative prognostic indicator.