Short-term outcomes for new-onset mild carpal tunnel syndrome better with steroid injection than splints

Reference

Chesterton LS, Blagojevic-Bucknall M, Burton C, et al. 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;392(10156):1423-1433.

Synopsis

These authors randomly assigned adults with mild CTS in an unblinded manner to receive a single corticosteroid injection (n = 116) or nocturnal wrist splint (n = 118). The patients, from primary care practices and community musculoskeletal clinics, had new-onset, mild, clinically diagnosed CTS of at least 6 weeks' duration. The steroid-treated patients received a 0.5 mL single dose of 40 mg/mL methylprednisolone acetate injected with a 23-gauge or 25-gauge needle inserted between the proximal and distal wrist crease. The splints, worn every night for 6 weeks, held the wrist either in a neutral position or in 20 degrees of extension. The authors assessed the main outcome after 6 weeks with the Boston Carpal Tunnel Questionnaire (BCTQ), a standardized CTS symptom scale that has 2 subscales: one assesses symptom severity and the other assesses function. The author also evaluated other outcomes intermittently for up to 24 months. After 6 weeks, the corticosteroid-treated patients had statistically greater improvement of their BCTQ score than those treated with splints (standardized mean difference 0.45). After 6 months, the corticosteroid-treated patients' BCTQ scores remained stable while those using splints had improved such that there was no net difference. The authors reported that no serious adverse events occurred and that the steroid-treated patients experienced only mild local effects: thinning, lightening, or darkening of the skin, or hot flushes. Additionally, nearly half of the steroid-treated patients reported 3 days of increased pain. The night splint group had more visits with their surgeons and primary care providers and more use of physical therapy, occupational therapy, and acupuncture.