Nailbed Injuries, Part I

A nailbed laceration caused by a skill saw. The proximal nail fold is avulsed, and the nail is lacerated in several places.

One of my colleagues recently saw a pretty bad fingernail injury.  A young man got his hand caught in a skill saw while on a construction job.  The nail was completely avulsed from under the eponychial fold, and the nail itself was sliced in half longitudinally, as pictured.

Underneath the nail, which was pretty macerated and determined to be unsalvageable by the treating physician, an underlying nailbed laceration is seen:

The nail was removed, revealing this underlying nail bed laceration.

This was a tough one, no doubt about it.  Before moving forward, think for a minute: how would you manage an injury like this?  Should you repair the nail bed and attempt to replace the nail?  What are possible complications if the nail is removed and the eponychial fold is not stented?  What should you tell the patient is his prognosis for regeneration of the nail and a good cosmetic outcome?

Nail bed injuries can be challenging for the emergency practitioner.  They are variable in their degree of severity and complexity, and there is no great consensus on a single best way to manage them.  A lot of what we do is based on common teaching from the hand surgery literature, with very little evidence driving our practice.  The bright side of this is that it leaves a lot of room for practicing the “art” of medicine.  Fortunately, this particular patient had an excellent outcome.  Below, you’ll find a video demonstrating the repair method used by the physician for this injury, including a few pointers on technique, and photographs of the outcome months later.

In bullet format, here are some principles regarding distal fingertip and nail bed injuries in general:

• Not all nail bed lacerations are obvious.  Even if the nail is intact, if a subungual hematoma is present that is greater than 1/2 the size of the nail bed, or if there is a distal phalanx fracture seen on x-ray, there is probably an underlying nail bed laceration.  This may be the case in a blunt injury mechanism such as a finger getting slammed in a door.
• Not every nail bed laceration requires nail removal and repair.  Just because a nail bed laceration is present, it doesn’t mean nail removal with obligate repair is indicated.  If the nail is firmly adherent and disruption of surrounding tissue is minimal, there is likely to be a good cosmetic outcome without primary nail bed repair.  However, it may be prudent to at least trepinate the subungual hematoma.
• Optimize the chances of nail regeneration.  If the nail is removed (or the proximal nail fold is already avulsed during the injury) it is a generally accepted rule that the eponychial fold is stented with some type of inert material (xerofoam, telfa, the nail itself, or aluminum from the suture package, as in this case) in order to prevent the base of the nail and the eponychial fold from scarring to the nail fold while the repair site is healing.  If this scarring occurs, it can result in a failure of nail regrowth. However, in Part II I’ll address some conflicting evidence regarding the utility of this standard practice.

Keep in mind–there is a lot of controversy regarding best practice for repair of nail bed lacerations, so my disclaimer is that these are general principles, and the video demonstrates just one of several ways to handle an injury like this.  It is not necessarily the only way nor the best way.  To that end, in Part II of this post, I discuss some of the new literature and novel techniques for management of nail bed injuries.