Comparison of Clinical and Electrophysiological Outcomes of Local Versus Intramuscular Steroid in Mild-to-Moderate Carpal Tunnel Syndrome: An Open-Label, Blinded Endpoint Randomized Clinical Trial.

Abstract

In view of paucity of studies, this study compared the effects of local versus intramuscular corticosteroid injections on clinical outcomes and electrophysiological parameters in patients with mild-to-moderate carpal tunnel syndrome (CTS). This study enrolled 190 CTS patients between October 2023 to March 2025. Participants were randomized to receive either a single local injection of 40 mg methylprednisolone (MP) with 0.5 mL lidocaine at the wrist (local corticosteroid injection [LCI] arm) or a single 40 mg intramuscular (IM) MP injection in the deltoid (IM arm). The primary outcome was the Symptom Severity Scale (SSS) score at 3 months. Secondary outcomes included SSS at 1 month, Functional Status Scale (FSS), and median nerve electrophysiological changes at 1 and 3 months. Significant clinical response was defined as a reduction of ≥0.8 points in SSS or ≥0.5 in FSS. Follow-up data were missing for 29 patients at 3 months. At 3 months, mean SSS score was 1.51 (<i>SD</i> 0.58) in LCI and 1.64 (<i>SD</i> 0.72) in IM arm (<i>P</i> = .21). However, the LCI arm showed significantly greater reduction in SSS/FSS scores at 1 month. Considering patients lost to follow-up as treatment failures, response rate at 3 months was 70.5% in LCI and 72.6% in IM arm (<i>P</i> = .75). Median nerve conduction results were comparable, although the LCI arm showed greater improvement at 3 months from baseline. In patients with mild-to-moderate CTS, LCI resulted in greater reduction in Boston Carpal Tunnel Questionnaire scores and in median nerve conductions at 1 month. However, outcome at 3 months was similar.