Background: Steroid injections are used in idiopathic carpal tunnel syndrome (CTS), but evidence of efficacy beyond 1 month is lacking.
Objective: To assess the efficacy of local methylprednisolone injections in CTS.
Design: Randomized, placebo-controlled trial. (ClinicalTrials.gov: NCT00806871).
Setting: Regional referral orthopedic department in Sweden.
Patients: Patients aged 18 to 70 years with CTS but no previous steroid injections.
Intervention: Three groups (37 patients each) received 80 mg of methylprednisolone, 40 mg of methylprednisolone, or placebo. The patients and treating surgeons were blinded.
Measurements: Primary end points were the change in CTS symptom severity scores at 10 weeks (range, 1 to 5) and rate of surgery at 1 year. Three patients had missing 10-week data. All patients had 1-year data.
Results: Improvement in CTS symptom severity scores at 10 weeks was greater in patients who received 80 mg of methylprednisolone and 40 mg of methylprednisolone than in those who received placebo (difference in change from baseline, -0.64 [95% CI, -1.06 to -0.21; P = 0.003] and -0.88 [CI, -1.30 to -0.46; P < 0.001], respectively), but there were no significant differences at 1 year. The 1-year rates of surgery were 73%, 81%, and 92% in the 80-mg methylprednisolone, 40-mg methylprednisolone, and placebo groups, respectively. Compared with patients who received placebo, those who received 80 mg of methylprednisolone were less likely to have surgery (odds ratio, 0.24 [CI, 0.06 to 0.95]; P = 0.042). With time to surgery incorporated, both the 80- and 40-mg methylprednisolone groups had lower likelihood of surgery (hazard ratio, 0.46 [CI, 0.27 to 0.77; P = 0.003] and 0.57 [CI, 0.35 to 0.94; P = 0.026], respectively).
Limitation: The study was conducted at 1 center, and wrist splinting had previously failed for all patients.
Conclusion: Methylprednisolone injections for CTS have significant benefits in relieving symptoms at 10 weeks and reducing the rate of surgery 1 year after treatment, but 3 out of 4 patients had surgery within 1 year.
Primary funding source: Region of Scania Research and Development Foundation and Hässleholm Hospital Organization.