A stratified investigation of a single injection of extended-release corticosteroid for symptomatic relief in patients with idiopathic adhesive capsulitis of the shoulder

Objectives: Failure of a corticosteroid injection and therapy to provide relief for shoulder adhesive capsulitis results in increasing healthcare costs and patient morbidity from repeat injections and possible surgical intervention. The purpose of this study was to examine the effects of an extended-release corticosteroid injection in shoulder adhesive capsulitis. Methods: This was a phase 2, prospective, non-blinded single-arm study of patients with idiopathic adhesive capsulitis of the shoulder who received a single, image-guided extended-release corticosteroid injection. The visual analog pain scale (VAS) was measured up to 12 months after injection. Secondary endpoints included American Shoulder and Elbow (ASES) score, range of motion (ROM), and need for re-injection. Results: Thirty-nine patients with a mean age of 55 ± 9 years were included; 32 (82%) experienced adequate symptom resolution after a single injection. Mean VAS improved from 5 to 1.4 ( p < 0.01), and mean ASES score improved from 43 to 80 ( p < 0.01) by 6-week post-injection, with sustained improvement through 1-year follow-up. Patients demonstrated improvements in mean passive forward elevation (117–173°; p < 0.01), abduction (98– 162°; p < 0.01), and external rotation with the arm adducted (32–59°; p < 0.01). Conclusion: A single intra-articular injection of extended-release corticosteroid was associated with sustained improvements in pain relief, patient-reported outcomes, and ROM in patients with idiopathic shoulder adhesive capsulitis.