Long-term Outcome of Local Steroid Injections Versus Surgery in Carpal Tunnel Syndrome: Observational Extension of a Randomized Clinical Trial

Abstract

Background: In a previous paper, we have demonstrated that: (1) local injection of corticosteroids for carpal tunnel syndrome (CTS) is as effective as decompressive surgery, at 1-year follow-up; and (2) surgery has an additional benefit in the 2-year follow-up. In this study, we assess the long-term outcomes of both therapies in an observational extension of the patients originally enrolled in our randomized clinical trial. Methods: Patients were included in an open, randomized clinical trial, comparing injections versus surgery in CTS. After the end of the clinical trial, patients received the treatment prescribed by their general practitioner or specialist. Therapeutic failure was defined as the need of any new therapeutic intervention on the involved wrist. Comparison between groups was made using Cox multiple regression analysis. Estimation of the accumulated incidence of new therapeutic failure was made considering the withdrawal as a competitive risk (Gooley’s test). Results: Of 163 randomized wrists at the beginning of the study, only 148 were available at the final follow-up. The mean follow-up was 6.3 and the median was 5.9 years. In the long-term follow-up, the accumulated incidence of therapeutic failure in the surgery group was 11.6% versus 41.8% in the injection group. The Cox multiple regression analysis showed a risk of failure associated with injection group of 4.5 (95% confidence interval [CI], 2.1-9.8; P < .0001). Conclusions: In long-term follow-up, surgery seems more effective than local corticosteroid injections in primary CTS. Nonetheless, about 58% of the patients in the injection group will not need further therapeutic interventions during the follow-up.