Nail Bed Laceration and Repair in the Emergency Department

How does one get a nail bed injury?

Distal phalanx injuries are the most common hand injury, particularly in children. These are often due to crush injuries also resulting in subungual hematomas and nail bed lacerations. If a subungual hematoma involves more than half the nail plate, there is a 60% chance of a nail bed laceration and a high likelihood of fracture.¹ If a distal phalanx fracture is present, there is a 95% chance of a nail bed laceration.¹ There is controversy about how to repair nail bed lacerations; however, current evidence and recommendations point toward less aggressive management as the way to go.²

What was the controversy?

In the past, it was recommended that any subungual hematoma that involved greater than 50% of the nail plate or any subungual hematoma with an associated distal phalanx fracture should undergo nail plate removal and exploration of the nail bed for repairable lacerations. This notion has since been discredited by several studies. Roser and Gellman et al,³ the most often cited trial, took 52 children with subungual hematomas and compared nail trephination alone versus nail plate removal and nail bed laceration repair. Their inclusion criteria were that patients had to have intact nail plate and intact nail margin. Although this was a small trial, they found no difference in outcome, regardless of hematoma size, presence of fracture, or mechanism of injury. What they did find is that nail plate removal and nail bed laceration repair resulted in four times the hospital charge for the patient.

So when is nail bed repair necessary?

Removal of the nail plate and repair of nail bed laceration should be performed if:

1. The nail plate is significantly fractured
2. The nail margin is injured
3. There is a significantly displaced fracture of the distal phalanx

Let’s look at some anatomy to understand these terms.

The nail plate is the actual fingernail. The nail margins just refer to the lateral nail folds, or paronychium, which serve to stabilize the nail plate. So, if the nail plate is intact and relatively well-attached to the nail bed (by intact nail margins), repair is unnecessary and simple trephination is recommended.  

How do I repair the nail bed?

Nail bed laceration repair should start with a digital block. There are multiple studies showing that the single injection, volar digital nerve block provides the same analgesia as the traditional method of injecting into the web space on either side of the digit.^4-8 This technique involves either injecting lidocaine into the flexor tendon sheath – called a transthecal block – or into the subcutaneous tissue at the fold of the MCP joint. Both techniques are equally efficacious, with the subcutaneous injection being slightly easier.^9-11 See these two posts for examples of how to perform each CoreEM – Transthecal Block and ALiEM – Subcutaneous Volar Block.

After anesthesia has been achieved, place a tourniquet on the finger at the middle phalanx, using the cut off finger of a glove. The remaining nail plate should be gently separated and removed from the nail bed with blunt dissection. Irrigate the whole area to prevent infection because these are technically open fractures – as mentioned before, 95% of injuries have an underlying distal phalanx fracture. Explore the nail bed thoroughly and suture any lacerations with 6-0 absorbable sutures. Alternatively, you can use skin adhesive glue for the repair.¹² If the patient’s nail plate is sufficiently intact, you should clean it and replace it between the eponychium (cuticle) and the nail bed in order to splint open the eponychium. This allows room for the new nail plate to grow. If the eponychium is not splinted open it will adhere to the nail bed, and the new nail plate growing from the nail matrix will be unable to progress distally.

You can suture the nail plate to the eponychium with two simple interrupted 5-0 nonabsorbable sutures (or one 5-0 nonabsorbable horizontal mattress) and maybe one simple suture at the hyponychium (the tip of the finger) to further stabilize.

You can also glue it in place, tape it in place, or just wrap the entire finger with gauze. If you don’t have the nail plate, use the suture casing material or another thin, clean material.¹³ When you are done, wrap the whole area and splint the entire finger. Despite this technically being an open fracture, antibiotics do not affect outcome unless the wound is grossly contaminated.¹⁴ Patients should follow up with a hand surgeon within 3-5 days to evaluate for healing and infection.

Conclusions:

1. Subungual hematomas with an intact nail plate and nail margins will only need simple trephination
2. Skin adhesive works as well as sutures for nail bed laceration repair
3. Make sure to splint open the eponychium with either the native nail plate or another material
4. Antibiotics are not helpful unless the wound is grossly contaminated

References

1. 1. Walls, Ron et al. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 9th ed.
2. 2. Patel L.Management of simple nail bed lacerations and subungual hematomas in the emergency department. Pediatr Emerg Care. 2014 Oct;30(10):742-5.
3. 3. Roser SE, Gellman H. Comparison of nail bed repair versus nail trephination for subungual hematomas in children. J Hand Surg Am. 1999 Nov;24(6):1166-70.
4. 4. Cannon B et al. Digital anaesthesia: one injection or two? Emerg Med J. 2010 Jul;27(7):533-6.
5. 5. Martin SP et al. Double-dorsal versus single-volar digital subcutaneous anaesthetic injection for finger injuries in the emergency department: A randomised controlled trial. Emerg Med Australas. 2016 Apr;28(2):193-8.
6. 6. Afridi RA et al. Comparison of the efficacy of single volar subcutaneous digital block and the dorsal two injections block. J Ayub Med Coll Abbottabad. 2014 Jan-Mar;26(1):88-91.
7. 7. Bashir MM et al. Comparison of traditional two injections dorsal digital block with volar block. J Coll Physicians Surg Pak. 2008 Dec;18(12):768-70.
8. 8. Antevy PM et al. Evaluation of a transthecal digital nerve block in the injured pediatric patient. Pediatr Emerg Care. 2010 Mar;26(3):177-80.
9. 9. Low CK et al. Comparison of transthecal and subcutaneous single-injection digital block techniques. J Hand Surg Am. 1997;22(5):901.
10. 10. Hung VS et al. Digital anaesthesia: comparison of the efficacy and pain associated with three digital nerve block techniques. J Hand Surg Br. 2005;30(6):581.
11. 11. Okur OM et al. Two injection digital block versus single subcutaneous palmar injection block for finger lacerations. Eur J Trauma Emerg Surg. 2017;43(6):863.
12. 12. Strauss EJ et al. A prospective, randomized, controlled trial of 2-octylcyanoacrylate versus suture repair for nail bed injuries. J Hand Surg Am. 2008 Feb;33(2):250-3.
13. 13. Weinand C, et al. A comparison of complications in 400 patients after native nail versus silicone nail splints for fingernail splinting after injuries. World J Surg. 2014 Oct;38(10):2574-9.
14. 14. Altergott C et al. Pediatric fingertip injuries: do prophylactic antibiotics alter infection rates? Pediatr Emerg Care. 2008 Mar;24(3):148-52.

Images:

1. 1. Patel L. Management of simple nail bed lacerations and subungual hematomas in the emergency department. Pediatr Emerg Care. 2014 Oct;30(10):742-5.
2. 2. Courtesy of Mann’s Surgery of the Foot and Ankle, 9th Edition
3. 3. Courtesy of Pfenninger and Fowler’s Procedures for Primary Care, 3rd Edition

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