Clinical scenario

A boy in his early childhood presented to the paediatric emergency department with a fingertip injury. His index finger was caught in the hinge of a door upon its closure. Examination revealed a subluxation of the fingernail and a laceration on the underlying nailbed. After repairing the nailbed laceration, you wonder whether to replace the nail plate or not.

Structured clinical question

In children with nail bed injuries (PATIENT), does replacing the nail plate after repair (INTERVENTION) result in a better cosmetic outcome or lower risk of infections (OUTCOME) compared to discarding the nail plate (COMPARISON)?

Search

A literature search was conducted using MEDLINE, Embase and the Cochrane Library with the following keywords: ‘nail bed injury’, ‘nail bed repair’, ’child’ and ‘paediatrics’. Studies comparing children with nail bed injuries who had their nails replaced and discarded after the procedure were included. Articles written in languages other than English were excluded. The search yielded a total of 58 articles, of which 3 were included as relevant articles. All three studies were conducted in the UK, and two were part of the same research project, which included a pilot study and a subsequent randomised controlled trial.1–3 The results of the review are summarised in table 1.

Summary

Refer to table 1 below.

Commentary

The fingertip is part of the body with a highly sophisticated function in sensing tactile stimuli, acting as the key to intricate human manoeuvres.4 Unfortunately, it is also known as the most common site of injury in children’s hands, accounting for more than two-thirds of paediatric hand trauma.5 It is estimated that around 700 000 children in the USA are treated annually for door-related distal tip injuries and around 10 000 children in the UK are operated on year for fingertip injuries.6 7

What makes the management of fingertip injuries unique is the presence of a hard nail plate covering the sterile underlying nail bed.8 The nail bed is the most commonly injured part of the fingertips, often associated with nail avulsion or distal phalangeal fracture.5 While trephination of the nail plate is often sufficient for isolated subungual haematomas with an intact nail plate, wound exploration with the removal of the overlying nail plate is often required in the management of nail bed injuries.5 8 A controversial issue after repair of nail bed injuries is whether to refix the nail plate to its original position (figure 1), which was reported to be done in more than 95% of cases in the 2010s.7 This practice has been surgical dogma for decades and has been justified for several reasons, including prevention of wound infection, splinting of the underlying distal phalangeal fracture and keeping the proximal nail fold open to ensure future nail regrowth.5 However, the true benefit of this practice over nail plate discard has not been evaluated in the paediatric population until recently.

• Download figure
• Open in new tab
• Download powerpoint

Figure 1

The case of a female toddler who got the nailbed of her right foot’s thumb lacerated with accompanied nail avulsion and distal phalanx fracture (A). After the nailbed repair (B), her nail plate was replaced with the Schiller method.

Among the three studies returned by the literature search, the first was a single-centre retrospective cohort study by Miranda et al in 2012,1 which looked at 111 children with nail bed injuries. Post-repair infections were much more common in the nail-replacement group, observed in 4 out of 51 patients (7.8%), compared with 0 out of 60 patients in the nail-discard group.1 Delayed healing was also more common in the nail-replacement group (11.7% vs 3.3%, p=0.004), and there was no significant difference in the incidence of patients with persistent pain or overgranulation.1

To provide strong evidence on nail replacement after nail bed repair, a multicentre randomised controlled trial called the Nail bed INjury Analysis (NINJA) trial was conducted.3 The NINJA trial recruited 451 children with suspected nail bed injuries from 20 hospitals across the UK.3 227 and 224 patients were randomised to nail replacement and nail discarding, respectively.3 The primary outcomes were surgical site infections at 7 days postoperatively and cosmetic appearance of the nail at 4 months postoperatively.3 Surgical site infections were more common in the nail-replacement group (2.2% vs 0.9%), although no statistically significant difference was observed after logistic regression adjustment for the recruitment site (OR 2.49, 95% CI 0.58 to 10.61).3 The cosmetic appearance of the nail was assessed using a scoring system from 5 to 0, with 5 being the best appearance. The median score was 5 in both groups, indicating that the cosmetic appearance of the nail was good in both groups.3 Health economic analysis of the NINJA trial showed that discarding the nail plate saved healthcare costs of £75 per patient.9

Overall, the included studies have disproved the myths about the benefits of nail replacement in preventing infection or improving cosmetic outcomes, making discarding the nail after nail bed repair a reasonable option. Owing to the difficulty in keeping the replaced nail plate sterile, it may have acted as a bacterial reservoir, increasing the risk of infection.1 The good cosmetic outcome of the nail in both groups negated the need to keep the proximal nail fold open by replacing the nail plate, which was consistent with the other prospective cohort study of children with avulsed nails without nail bed injury.10

The initial study by Miranda et al had several limitations due to its retrospective nature and small sample size.1 Moreover, data on the severity of nail bed injury or associated distal fracture in each group was lacking, which could influence the complication rate.1 11 The subsequent NINJA trial overcame these limitations by organising a multicentre randomised controlled trial with a robust design.3 The sample size of the NINJA trial was calculated to have sufficient power by using the results of the pilot and feasibility study by Greig et al, which included 60 children with nail bed injuries.2 3 Although blinding of treatment allocation was difficult due to the nature of the procedure, assessment of cosmetic nail appearance was performed by blinded independent assessors.3 Poor inter-rater agreement in the assessment of cosmetic nail appearance in the pilot study was addressed in the NINJA trial by creating a new simple scoring system with better inter-rater agreement.2 3 12 The study design and planned statistical analysis of the NINJA trial were published before the publication of the main study,13 14 which reduced the risk of reporting bias.15

Although the results of the NINJA trial are robust, it is important to note that they cannot be applied to all paediatric nail bed injuries. Patients included in the NINJA trial were children with simple nail bed injuries with or without associated germinal matrix injury, pulp laceration or tuft fracture of the distal phalanx.13 Some complicated injuries were excluded from the study. An example is the Seymour fracture, which is an open, displaced fracture at the growth plate of the distal phalanx with overlying nail bed lacerations.16 Instability of the fracture often requires fixation with a Kirschner wire,16 which is one of the exclusion criteria for the NINJA trial.13 Children with amputation of the fingertips including the nail bed and those with wound infection at the time of presentation were also excluded from the analysis. 13 The decision to replace or discard nail plates in these patients should be considered on a case-by-case basis at the discretion of the hand surgeon.

Another factor to consider is the clinical setting of the procedure in the included studies. Although all nail bed repairs in the included studies were performed by plastic surgeons in the operating room,1–3 this may be different in other institutions. Two single-centre retrospective studies from tertiary hospitals in Canada and Singapore found that approximately 40% and 70% of nail bed injuries were repaired by paediatric emergency physicians.11 17 The Singapore study showed that approximately 80% of these procedures were performed on awake patients,11 in contrast to the NINJA trial, where 90% of patients were treated under general anaesthesia.3 Since there is no difference in the procedure itself, it seems reasonable to apply the nail-discard principle if both nail bed exploration and definitive treatment are performed in the paediatric emergency department. Moreover, nail replacement would impose additional physical and psychological pain on patients if they are awake during the procedure, further supporting the practice of discarding the nail. Future observational studies of nail bed injuries in paediatric emergency departments after the introduction of the nail discarding principle would help to assess the external validity of the practice in settings other than those of the NINJA trial.