Effectiveness of Ultrasound-Guided Compared to Blind Steroid Injections in the Treatment of Carpal Tunnel Syndrome

Objective. To compare the effectiveness of ultrasound-guided injections to blind injections in the treatment of carpal tunnel syndrome (CTS) in a large community-based cohort. Methods. This study evaluated residents of Olmsted County, Minnesota, treated with a corticosteroid injection for CTS between 2001 and 2010. The proportion of patients receiving retreatment and the duration of retreatment-free survival between blind and ultrasound-guided injections were compared. Propensity score matching was used to control for confounding by indication. Results. In the matched data set consisting of 234 (of 600) hands treated with a blind injection and 87 (of 89) ultrasound-guided injection cases, ultrasound guidance was associated with a reduced hazard of retreatment (hazard ratio 0.59 [95% confidence interval (95% CI) 0.37-0.93]). In addition, ultrasound guidance was associated with 55% reduced odds of retreatment within 1 year compared to blind injections (adjusted odds ratio 0.45 [95% CI 0.24-0.83]). Conclusion. This study indicates that ultrasound-guided injections are more effective in comparison to blind injections in the treatment of CTS.