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The NINJA study is a pilot study which will assess whether a study that looks at whether nail plates should be discarded or replaced after nail bed injury in children is feasible in the NHS.

Nail bed INJury Analysis (NINJA) Pilot Study:

Should the nail plate be replaced or discarded after nail bed repair in children?

The NINJA Pilot Study (funded by the British Society for Surgery of the Hand, BSSH) is a pragmatic multicentre study to assess whether the nail should be replaced or discarded after nail bed repair in children.  The pilot will inform the design and conduct of a larger NINJA study with regards to recruitment, data collection and outcome measurement.  The Surgical Intervention Trials Unit (SITU) at the University of Oxford, will co-ordinate the trial.  This is the first plastic surgery trial of its kind and will form part of a developing research portfolio for the plastic surgery community.


Nail bed injuries are common and account for the majority of paediatric hand trauma cases treated by hand surgery units. The typical patient is a toddler who has caught their finger in a closing door. A single tertiary referral hand surgery unit will on average treat two to three patients with nail bed injuries per day.


Despite their frequency, controversy remains around the best treatment of nail bed injuries. Without proper treatment, injury to the nail complex has the potential to cause considerable dysfunction and/or deformity. The long-accepted surgery to repair the nail bed involves removing the fingernail (which is often broken or partially detached already) and carefully repairing the nail bed underneath using tiny dissolving stitches.  This is important to help the new nail to grow out smoothly and look as normal as possible in the future. After repairing the nail bed, the surgeon can do one of two things:


  1. Replace the old nail before applying dressings
  2. Discard the nail and apply dressings straight onto the nail bed.

In both techniques, a new fingernail grows out from the base of the nail bed over a few months. The old nail cannot grow again after it has been removed and it is eventually pushed off by a new nail growing underneath it.  Both of these techniques are routinely done by surgeons in the NHS, but we don’t know which one is best.

The rationale for replacing the nail is that it both protects the nail bed repair and acts as a ‘splint’ by holding open the nail fold and preventing scarring between the nail fold and the nail bed (synechiae).

However, there is no evidence that replacing the nail has better results than not replacing it and there is a suggestion that it may be associated with a small risk of infection.

Therefore the aim of a large NINJA study will be to find out if there is any difference between the two techniques



The objectives of the NINJA Pilot Study are to:

  • Assess and monitor recruitment of patients to a study of this nature
  • Identify any conflict or areas of concern with conducting research with this patient population and with the Plastic Surgery network
  • Evaluate the recruitment process
  • Test assessment tools to be used
  • Monitor patient compliance with follow up procedures
  • Gather information to develop the larger study and to calculate how many patients will be required for this

Randomisation will occur in the anaesthetic room via an internet portal.  Follow up is at 2 weeks, 30 days and 4 months post randomisation.  



May 2014                    BSSH Award

December 2014          Protocol finalised and Ethics submission      

January 2015              Ethics approval

March 2015                 Site set-up

April 2015                    Patient recruitment (first patient recruited on 21st April 2015)

June 2015                   Main trial funding application

July 2015                     Last patient recruited 

November 2015           Pilot Follow up complete


Our team