History
A complete history for a nail bed (nailbed) injury should include hand dominance, time of the injury, the presence of an associated open wound, previous history of hand injury, tetanus status, occupation and hobbies, and the patient's overall health. All of these aspects of the patient's presentation may affect the treatment plan for the injury. Also, inquire about the circumstances of the accident, as the mechanism of injury has prognostic implications for severity of injury and wound contamination.
Most injuries of the nail bed involve the fingertip versus an isolated nail bed injury (6:1 ratio). The right and left hands are affected equally. However, the long finger is most often affected, since it is usually the last to be pulled from a situation that has the potential to cause trauma. After the long finger, the ring finger, index finger, pinky finger, and thumb are affected in that order. The middle and distal third of the nail are the most frequent sites of injury.
Crush and avulsion injuries, as well as injuries associated with distal phalanx fractures, have a worse prognosis. Injuries that span the entire nail bed or most of the bed and fold also fare worse than those that are isolated to one to two thirds of the nail bed or only to the nail fold and germinal matrix.
Physical Examination
A general examination is necessary to rule out additional injuries.
The injured finger can usually be examined without anesthesia, although children or those in severe pain may require a digital block first. A complete sensory examination (performed prior to a digital block), as well as motor function and vascular supply, is necessary. If the nail is avulsed from the nail fold and is unstable, a digital block will usually be necessary to accurately examine the extent of injury. Loupe magnification may be used if necessary.
The presence and extent of devascularized and macerated skin should be noted as the presence of active bleeding, a subungual hematoma, avulsion of the nail, disruption of the nail bed, and any specific pattern of laceration (linear, stellate, flap) of the nail bed if visible. Observe the posture of the fingers, and look for any presence of deformities signifying fracture, dislocation, or tendon avulsion, as well as the presence of glass, wood, metal, or other foreign-body fragments.
Nail bed (nailbed) injuries are often accompanied by subungual hematomas, lacerations to the surrounding skin, crush or avulsion injuries to the distal finger, and associated fractures of the distal phalanx.
A subungual hematoma is a common presentation, and the possibility of an underlying nail bed laceration or injury should always be considered. Lacerations of the nail bed associated with subungual hematomas are most often stellate. Simple lacerations are uncommon unless an accompanying crushing component that was strong enough to collapse the nail through the nail bed and onto the distal phalanx or to fracture the distal phalanx occurred. Fracture of the distal phalanx usually disrupts the matrix but may not break the nail.
The nail may also be partially or completely avulsed from the nail fold. Nail plate avulsion is almost invariably accompanied by significant nail bed laceration that requires repair. Fractures of the distal phalanx are present in 50% of nail bed injuries. [14]
A Seymour fracture is an injury unique to children and requires prompt attention. Following crush injury or axial load, an angulated Salter-Harris type I or II fracture of the distal phalanx with an associated nail bed injury might result. The nail plate is typically avulsed proximally from the nail fold, and soft tissue (often the germinal matrix of the nail) might become interposed in the fracture, preventing reduction and healing. The typical presentation is a swollen, ecchymosed, and painful finger that is flexed at the distal interphalangeal joint (DIPJ). [15]
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Trephination of a subungual hematoma.
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Nailbed repair.
