Background/Purpose:

Patients with idiopathic carpal tunnel syndrome (CTS) are commonly treated with local steroid injection but there is currently no evidence from placebo-controlled trials supporting efficacy beyond 1 month.

Methods:

We conducted a randomized triple-blind placebo-controlled trial of first-time steroid injection into the carpal tunnel in patients with moderately severe CTS. Patients aged 18 to 70 years with primary idiopathic CTS, no severe sensory loss or muscle atrophy, and no previous steroid injection for CTS were randomized to 1 of 3 groups (37 patients in each): 80 mg Methylprednisolone, 40 mg Methylprednisolone, or saline (each also containing 10 mg Lidocaine). Patient-reported outcomes (CTS symptom severity scale, QuickDASH, SF-36 bodily pain, and SF-6D) were obtained and physical examination by a blinded assessor was performed at baseline and at 10, 24 and 52 weeks after injection. The primary end points were change in CTS symptom severity score at 10 weeks and rate of surgery at 52 weeks. Data from all patients were analyzed.

Results:

During 1 year after injection surgery was carried out on 27 patients (73%) in the 80 mg Methylprednisolone group, on 30 patients (81%) in the 40 mg Methylprednisoline group, and on 34 patients (92%) in the placebo group. Patients who received placebo were significantly more likely to have surgery during 1 year after injection than patients who received Methylprednisolone; adjusted hazard ratio 2.0 (95% confidence interval 1.3-3.2, P<0.01). The change in the CTS symptom severity score from baseline to 10 weeks was significantly larger in both Methylprednisolone groups than in the placebo group. 

Conclusion:

In patients with moderately severe carpal tunnel syndrome first-time steroid injection into the carpal tunnel has a significant benefit in relieving symptoms up to 10 weeks and in reducing the need for surgery up to 1 year after treatment.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/randomized-placebo-controlled-trial-of-local-steroid-injection-for-moderately-severe-carpal-tunnel-syndrome/