Clinical outcomes of posterior tibial tendon sheath ultrasound-guided corticosteroid injections.

Objectives: The purpose of this study was to assess the safety of ultrasound-guided corticosteroid injections into the posterior tibial tendon sheath for posterior tibialis tendinopathy. Secondary outcomes include duration of pain relief, amount of pain relief, need for repeat injections and progression to surgery.

Methods: We retrospectively reviewed all patients in our electronic medical record who underwent a posterior tibial tendon sheath (PTTS) steroid injection between 2015 and 2020 for the diagnosis of posterior tibial tendon dysfunction and/or posterior tibialis tendon insufficiency, and/or ankle pain. Demographic information was obtained from the patient record in addition to MRI data, clinical response to injection based on follow-up visits, number of total injections and progression to surgery. Thirty-eight posterior tibial tendon sheath ultrasound-guided injections were administered in 33 patients who met inclusion criteria during the 5-year study period.

Results: Thirty-three patients were included in the study with a total of 38 injections performed. Eighteen of 38 (47%) injections yielded good or better pain relief. Seven of 33 patients (21%) progressed to surgery. There were no reported complications with the 38 performed injections.

Conclusion: Ultrasound-guided corticosteroid injection into the posterior tibial tendon sheath is a safe nonoperative treatment modality for progressive collapsing foot deformity. The efficacy of the injection appears highly variable with 47% of injections yielding 'good' or better clinical results. When evaluating body mass index (BMI), obese patients (BMI ≥30.0) were found to have a more sustained response to injection (P = 0.029) and more pain relief (P = 0.049) than non-obese patients.