Nail bed INJury Assessment Pilot (NINJA-P) study: should the nail plate be replaced or discarded after nail bed repair in children? Study protocol for a pilot randomised controlled trial

Background: Nail bed injuries account for the majority of paediatric hand trauma cases. Despite their frequency, controversy remains regarding their treatment. The accepted teaching is to remove the fingernail, repair the underlying nail bed with fine sutures and replace the nail under the nail fold. A recent study by Miranda et al. (Plast Reconst Surg. 129(2):394e-396e, 2012) suggests that replacing the nail is associated with increased complications, in particular post-operative infection. Nail bed INJury Assessment Pilot (NINJA-P) is an external pilot study for a large pragmatic, multicentre, randomised, controlled study (NINJA) to assess whether the nail should be replaced or discarded after nail bed repair in children under the age of 16.

Methods/design: NINJA-P is a randomised pilot study. The participants are patients below 16 years of age who require surgical repair of the nail bed. Eligible patients will be randomised to receive one of two possible interventions. Group 1 will have the nail replaced after nail bed repair, and group 2 will have the nail discarded. The clinical outcome measures include the presence of post-operative complications at 2 weeks and 30 days, the cosmetic appearance of the nail at 4 months and the level of pain experienced by the child at their first dressings change at 2 weeks. In order to inform the design of the main NINJA trial, the following feasibility data will also be recorded: the number of potentially eligible children and the proportion which agree to take part in the study, the proportion of children who received the allocated treatment and reasons for any non-compliance and the proportion of participants with a valid response at each follow-up point. Neither the patient, family members nor treating physicians will be blinded. A replaced nail can take several weeks to fall off once a new nail has grown out. The cosmetic appearance of the nail at 4 months will be assessed by a blinded assessor.

Discussion: The NINJA-P pilot study will inform the design and execution of the NINJA trial, which will assess whether the nail should be replaced or discarded after nail bed repair in children under 16. It will provide randomised comparative evidence for the treatment of this common injury.

Trial registration: First participant randomised: 21/04/2015, UKCRN Portfolio ID: 18516, ISRCTN16571591.