Efficacy of splinting the wrist and metacarpophalangeal joints for the treatment of Carpal tunnel syndrome: an assessor-blinded randomised controlled trial

OBJECTIVES: To compare the efficacy of a traditional cock-up splint, which supports the wrist only, with a modified splint that supports the wrist and the metacarpophalangeal (MCP) joints of the medial four digits in the treatment of carpal tunnel syndrome (CTS). DESIGN: An assessor-blind randomised controlled trial. SETTING: Hospital-based hand therapy clinics. PARTICIPANTS: Fifty-nine adults with mild-to-moderate CTS were randomly assigned to wear a wrist splint (control group) or an MCP splint (intervention group) for 6 weeks. OUTCOME MEASURES: The standardised outcome measures used included grip and pinch strength, the static two-point discrimination test, Phalen’s manoeuvre test, Tinel’s sign and the Boston CTS Questionnaire. RESULTS: Both groups improved significantly from splint use in some clinical features. The wrist splint and the MCP splint groups had significant improvements in lateral pinch strength (p=0.032 and p=0.002, respectively), two-point discrimination of the thumb (p=0.003 and p=0.041, respectively), two-point discrimination of the index (p=0.035 and p=0.023, respectively) and the Phalen’s manoeuvre symptoms (p=0.025 and p=0.002, respectively). The MCP splint group had additional improvements over the wrist splint group in tip pinch (p=0.012) and Palmar pinch (p=0.011) strength. CONCLUSION: Splinting is a practical and effective intervention option for improving the symptoms of CTS. A wrist splint that incorporates the MCP joints is more effective than the traditional wrist-only splint, with long-lasting improvements that remained consistent after 6 months of the splint intervention. Using the more effective MCP splint may consequently reduce disability, facilitate return to work and lower the associated costs. TRIAL REGISTRATION NUMBER: ISRCTN13189602.