Table 1 Eligibility criteria

Male or female aged ≥ 18 years

Corticosteroid injection or night splints for CTS in the affected wrist within preceding 6 months

A clinical diagnosis of unilateral or bilateral CTS as made by a GP or trained clinician according to the diagnostic criteria

Severe CTS exhibiting constant numbness or pain, constant sensory loss, severe Thenar muscle atrophy or symptom severity which requires the patient to be referred for a surgical opinion

Mild (e.g. intermittent paraesthesia) or moderate (e.g. constant paraesthesia, reversible numbness and/or pain) severity CTS of idiopathic nature

Any previous surgery on the affected wrist (or study wrist in the case of bilateral symptoms)

Symptom duration of episode of at least 6 weeks

Clinical suspicion of local or systemic sepsis or infection

Written informed consent provided by the patient, prior to any trial specific procedures

Current or previous infection of the affected wrist

Trauma to the affected hand requiring surgery or immobilisation in the previous 12 months

Unable to tolerate the study interventions

Unable to understand and complete self-report questionnaires written in English

Inter-current illness including, but not limited to:

 • poorly controlled thyroid disease

 • poorly controlled diabetes mellitus

 • vibration-induced neuropathy

 • inflammatory joint disease

 • suspected complex neurological conditions

 • any other severe medical illness which in the opinion of the local Principal Investigator (or other authorised clinical delegate) precludes trial participation

Pregnant or lactating females

Receiving anticoagulants

Any history of hypersensitivity to Depo-Medrone or any of its excipients

Allergy to any of the splint materials

Known abuse of drugs or alcohol

Involved in on-going litigation cases for their condition