Local Steroid Injection delays need for surgery in Carpal Tunnel Syndrome: JAMA

Local steroid injection is commonly used in treating patients with idiopathic carpal tunnel syndrome, but evidence regarding long-term efficacy is lacking.

A group of researchers from Sweden conducted a study to assess the long-term treatment effects of local steroid injection for carpal tunnel syndrome.

This exploratory 5-year extended follow-up of a double-blind, placebo-controlled randomized clinical trial was conducted from November 2008 to March 2012 at a university hospital orthopedic department. Participants included patients aged 22 to 69 years with primary idiopathic carpal tunnel syndrome and no prior treatment with local steroid injections. Data were analyzed from May 2018 to August 2018. Patients were randomized to injection of 80 mg methylprednisolone, 40 mg methylprednisolone, or saline.

The coprimary outcomes were the symptom severity score and rate of subsequent carpal tunnel release surgery on the study hand at 5 years. Secondary outcomes were time from injection to surgical treatment, SF-36 bodily pain score, and score on the 11-item disabilities of the arm, shoulder, and hand scale.

The results of the study are as follows:

• A total of 111 participants were randomized, with 37 in the 80 mg methylprednisolone group, 37 in the 40 mg methylprednisolone group, and 37 in the saline placebo group.
• Complete 5-year follow-up data were obtained from all 111 participants with no dropouts
• At baseline, mean (SD) symptom severity scores were 2.93 (0.85) in the 80 mg methylprednisolone group, 3.13 (0.70) in the 40 mg methylprednisolone group, and 3.18 (0.75) in the placebo group, and at the 5-year follow up, mean (SD) symptom severity scores were 1.51 (0.66) in the 80 mg methylprednisolone group, 1.59 (0.63) in the 40 mg methylprednisolone group, and 1.67 (0.74) in the placebo group.
• Compared with placebo, there was no significant difference in mean change in symptom severity score from baseline to 5 years for the 80 mg methylprednisolone group or the 40 mg methylprednisolone group.
• After injection, subsequent surgical treatment on the study hand was performed in 31 participants (83.8%) in the 80 mg methylprednisolone group, 34 participants (91.9%) in the 40 mg methylprednisolone group, and 36 participants (97.3%) in the placebo group; the number of participants who underwent surgical treatment between the 1-year and 5-year follow-ups was 4 participants (10.8%) in the 80 mg methylprednisolone group, 4 participants (10.8%) in the 40 mg methylprednisolone group, and 2 participants (5.4%) in the placebo group.
• All surgical procedures were conducted while participants and investigators were blinded to type of injection received.
• The mean (SD) time from injection to surgery was 180 (121) days in the 80 mg methylprednisolone group, 185 (125) days in the 40 mg methylprednisolone group, and 121 (88) days in the placebo group. Kaplan-Meier survival curves showed statistically significant difference in time to surgical treatment.

Thus, the researchers concluded that in idiopathic carpal tunnel syndrome, local methylprednisolone injection resulted in statistically significant reduction in surgery rates and delay in need for surgery.

Reference:

Extended Follow-up of Local Steroid Injection for Carpal Tunnel Syndrome

A Randomized Clinical Trial by Manfred Hofer et al. published in the JAMA Netw Open.

doi:10.1001/jamanetworkopen.2021.30753