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.