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.
Interventions: 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.
Results: A total of 111 participants (mean [SD] age at follow-up, 52.9 [11.6] years; 81 [73.0%] women and 30 [27.0%] men) 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 (100% follow-up). 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 (0.14 [95%CI, -0.17 to 0.45]) or the 40 mg
methylprednisolone group (0.12 [95%CI, -0.19 to 0.43]). 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 (log-rank test: 80 mg
methylprednisolone vs placebo, P = .002 ; 40 mg
methylprednisolone vs placebo, P = .02;
methylprednisolone 80 mg vs 40 mg, P = .37).
Conclusions and Relevance: ClinicalTrials.gov Identifiers: NCT00806871 and NCT02652390.