At five years, symptom severity does not differ, but rates of subsequent surgical treatment are lower in patients with idiopathic carpal tunnel syndrome receiving local methylprednisolone injection versus saline placebo injection, according to a study published online Oct. 22 in JAMA Network Open.
Manfred Hofer, from Kristianstad Hospital in Sweden, and colleagues assessed the long-term treatment effects of local steroid injection for carpal tunnel syndrome. The analysis included extended follow-up for 111 patients (aged 22 to 69 years) with primary idiopathic carpal tunnel syndrome and no prior treatment with local steroid injections. Patients were randomly assigned to injection into the carpal tunnel with 80 mg methylprednisolone (37 patients), 40 mg methylprednisolone (37 patients), or a saline placebo (37 patients).
The researchers found that compared with placebo, there was no significant difference in mean change in symptom severity score from baseline to five years for the 80-mg methylprednisolone group (0.14; 95 percent confidence interval [CI], −0.17 to 0.45) or the 40-mg methylprednisolone group (0.12; 95 percent CI, −0.19 to 0.43). Surgical treatment on the study hand following injection was performed in 83.8 percent of participants in the 80-mg methylprednisolone group, 91.9 percent in the 40-mg methylprednisolone group, and 97.3 percent in the placebo group; the percentages of participants who underwent surgical treatment between one-year and five-year follow-up were 10.8, 10.8, and 5.4 percent, respectively. The mean time from injection to surgery was 180, 185, and 121 days in the 80-mg methylprednisolone group, 40-mg methylprednisolone group, and placebo group, respectively.
“This randomized clinical trial found that local steroid injection resulted in reduction in rate of surgical treatment for individuals with carpal tunnel syndrome but not in significant differences in symptoms at five years,” the authors write.