Comparison of proximal and distal corticosteroid injections for carpal tunnel syndrome.

Introduction: Evidence for the efficacy of distal corticosteroid injection compared with proximal injection in carpal tunnel syndrome (CTS) is inadequate.

Methods: We conducted a randomized, double-blind noninferiority trial of 131 wrists with CTS. Forty milligrams of methylprednisolone was injected medial to the palmaris longus tendon 2 cm proximal to the wrist crease, or at the volar aspect, 2 to 3 cm distal to the wrist crease. Proximal & distal groups received a placebo. The primary outcome was difference in CTS Symptom Severity Scale (SSS) score at 1 month. Secondary outcome measures included the difference in SSS score at 3 months, Functional Status Scale (FSS) score at 1 and 3 months, and pain of injections.

Results: No significant differences were noted between groups in scores on the SSS and FSS. Pain was lower in the proximal group compared with the distal group.

Discussion: Corticosteroid injections for CTS distal to the wrist are not inferior to proximal injections, yet they are more painful.