The Clinical and Cost-Effectiveness of Corticosteroid Injection Versus Night Splints for Carpal Tunnel Syndrome (INSTINCTS Trial): An Open-Label, Parallel Group, Randomised Controlled Trial

Lancet. 2018 Oct 20;392(10156):1423-1433. doi: 10.1016/S0140-6736(18)31572-1.

Abstract

Background: To our knowledge, the comparative effectiveness of commonly used conservative treatments for carpal tunnel syndrome has not been evaluated previously in primary care. We aimed to compare the clinical and cost-effectiveness of night splints with a corticosteroid injection with regards to reducing symptoms and improving hand function in patients with mild or moderate carpal tunnel syndrome.

Methods: We did this randomised, open-label, pragmatic trial in adults (≥18 years) with mild or moderate carpal tunnel syndrome recruited from 25 primary and community musculoskeletal clinics and services. Patients with a new episode of idiopathic mild or moderate carpal tunnel syndrome of at least 6 weeks' duration were eligible. We randomly assigned (1:1) patients (permutated blocks of two and four by site) with an online web or third party telephone service to receive either a single injection of 20 mg methylprednisolone acetate (from 40 mg/mL) or a night-resting splint to be worn for 6 weeks. Patients and clinicians could not be masked to the intervention. The primary outcome was the overall score of the Boston Carpal Tunnel Questionnaire (BCTQ) at 6 weeks. We used intention-to-treat analysis, with multiple imputation for missing data, which was concealed to treatment group allocation. The trial is registered with the European Clinical Trials Database, number 2013-001435-48, and ClinicalTrial.gov, number NCT02038452.

Findings: Between April 17, 2014, and Dec 31, 2016, 234 participants were randomly assigned (118 to the night splint group and 116 to the corticosteroid injection group), of whom 212 (91%) completed the BCTQ at 6 weeks. The BCTQ score was significantly better at 6 weeks in the corticosteroid injection group (mean 2·02 [SD 0·81]) than the night splint group (2·29 [0·75]; adjusted mean difference -0·32; 95% CI -0·48 to -0·16; p=0·0001). No adverse events were reported.

Interpretation: A single corticosteroid injection shows superior clinical effectiveness at 6 weeks compared with night-resting splints, making it the treatment of choice for rapid symptom response in mild or moderate carpal tunnel syndrome presenting in primary care.

Funding: Arthritis Research UK.

Publication types

  • Multicenter Study
  • Pragmatic Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anti-Inflammatory Agents / administration & dosage*
  • Carpal Tunnel Syndrome / economics
  • Carpal Tunnel Syndrome / therapy*
  • Cost-Benefit Analysis
  • Female
  • Humans
  • Injections*
  • Male
  • Methylprednisolone / administration & dosage
  • Methylprednisolone / analogs & derivatives*
  • Methylprednisolone Acetate
  • Middle Aged
  • Severity of Illness Index
  • Splints*
  • Surveys and Questionnaires
  • Treatment Outcome

Substances

  • Anti-Inflammatory Agents
  • Methylprednisolone Acetate
  • Methylprednisolone

Associated data

  • ClinicalTrials.gov/NCT02038452