EVIDENCE-BASED ANSWER:
Yes. Injected corticosteroids reduce symptoms of carpal tunnel syndrome (CTS) more effectively than placebo or systemic steroids, but no better than anti-inflammatory medication and splinting, from one to 12 weeks after therapy (strength of recommendation [SOR]: A, meta-analysis of randomized controlled trials [RCTs] and consistent RCT).
A 40-mg injection of methylprednisolone reduces symptoms as effectively as an 80-mg injection for as long as 10 weeks, but the 80-mg dose reduces progression to surgery at one year (SOR: B, RCT). Long-term effects of injections decrease by 12 months (SOR: B, RCT).
After corticosteroid injections, 14% of patients proceed to surgery at one year, and 33% proceed to surgery at 5 years (SOR: B, cohort trial).
EVIDENCE SUMMARY
A 2007 Cochrane review of 12 RCTs with 671 patients compared the efficacy of corticosteroid injections for CTS with placebo injections or other nonsurgical interventions.1 Patients who received corticosteroid injections showed clinical improvement at one month or less compared with placebo (2 trials, 141 patients; 73% corticosteroids vs 28% placebo; relative risk [RR]=2.58; 95% confidence interval [CI], 1.72-3.87; number needed to treat [NNT]=2).
Compared with systemic corticosteroids, corticosteroid injections didn’t improve symptoms on a Global Symptom Score (scale of 0-50, with 50 indicating the most severe symptoms) at 2 weeks (one trial, 60 patients; mean difference [MD]= −4.2; 95% CI, −8.7 to 0.26), but did improve symptoms at 8 weeks (MD= −7.16; 95% CI, −11.5 to −2.86) and 12 weeks (MD= −7.1; 95% CI, −11.7 to −2.52).
Patients showed no difference in scores between corticosteroid injection and oral anti-inflammatory medication with neutral angle wrist splints on the Symptom Severity Scale (1 to 5, with 5 indicating the most severe symptoms) at 2 weeks (1 trial, 23 patients [37 wrists]; MD=0.0; 95% CI, −0.64 to 0.64) or 8 weeks (MD=0.1; 95% CI, −0.33 to 0.53).