Among a prospectively enrolled group of 49 patients (54 wrists) with mild or moderate carpal tunnel syndrome (CTS) who received a single corticosteroid injection, 79% experienced symptom relief at six weeks. Reporting in the October 7, 2015 edition of The Journal of Bone & Joint Surgery, Blazar et al. found that the rate of freedom from symptom recurrence in this cohort was 53% at six months and 31% at one year after injection. During the study period, 19 wrists underwent surgical carpal tunnel release at a median time of 181 days post-injection.
Diabetic patients in the study (13% of the wrists enrolled) were at a 2.6-fold greater risk of reporting recurring symptoms within one year of follow-up. In a univariable analysis, a 1-point increase in the baseline Boston Carpal Tunnel Questionnaire symptom score increased the risk of patients reporting post-injection symptoms by 5%, but that association became nonsignificant during multivariable analysis. Pre-injection symptom duration, patient age, and pre-injection electrophysiologic grade did not predict either symptom recurrence or subsequent intervention.
Blazar et al. add that their exclusion of people with normal electromyography results and those with severe carpal tunnel syndrome created a rather homogenous study population. Thus, they say, “these results may not be generalizable to all patients who present with clinical signs or symptoms of carpal tunnel syndrome.” Still, the findings should help orthopaedists counsel patients with CTS about the results they might expect from a single corticosteroid injection.