Comparison of local versus intramuscular steroid injection in patients with carpal tunnel syndrome: A prospective open label randomized clinical trial.

AIM: This study compared the efficacy and safety of local corticosteroid injection (LCI) vs intramuscular (IM) corticosteroid injection in mild to moderate carpal tunnel syndrome (CTS).

METHODS: This is an open labeled, randomized controlled trial conducted during December 2021 to August 2023. Eighty-six patients with CTS were randomized in 1:1 ratio to receive either single 40 mg methylprednisolone (MP) injection at the wrist (LCI arm), or single 40 mg MP intramuscular injection (IM arm) in the deltoid. Primary outcome was absolute Symptom Severity Scale (SSS) at 3 months. Secondary outcomes were SSS score at 1-month, Functional Status Scale (FSS) score at 1 and 3 months, and recurrence at 3 months and injection site pain assessed on visual analog (VAS) scale.

RESULTS: Median age was 45 (range 22 - 80) years, and 86 % were females. Baseline characteristics were comparable between groups. Mean SSS score at 3 months was similar in two arms (1.72 ± 0.71 vs 2.0 ± 0.93) with mean difference (MD) -0.03 (-0.31 to 0.25, p = 0.83) after adjusting for baseline SSS scores. LCI, however, resulted in significantly better SSS (1.48 ± 0.51 vs 1.88 ± 0.69, adjusted p = 0.04), and FSS scores (1.57 ± 0.44 vs 1.80 ± 0.66, adjusted p = 0.03) at 1 month compared to IM arm. Response rate (67.4 % vs 55.8 %; p = 0.30) and recurrence rate (17.1 % vs 22.6 %,p = 0.74) (26.7 % vs 23.3 %) at 3 months were similar. Injection site pain was severe in LCI arm[median 5 (range 3 - 8) vs median 3 (range 2 - 6)].

CONCLUSIONS: In patients with mild to moderate CTS, LCI resulted in better improvement in the BCTQ scores at 1 month compared to IM steroid. However, 3-month's outcome was similar. Intramuscular steroid injection was better tolerated.