Fingernail injuries are injuries to nail bed which consists of the nail matrix. Fingernail injuries can be divided into that of the sterile matrix and germinal matrix.
In general, germinal matrix injuries are more serious. An injury in this region has a higher likelihood of permanently affecting nail growth.
Classification of Acute Fingernail Injuries
Van Beek et al. classification of acute fingernail injuries is –
Germinal Matrix Injury
- GI: Small subungual hematoma proximal nail (25%)
- GII: Germinal matrix laceration, large subungual hematoma (50%)
- GIII: Germinal matrix laceration and fracture
- GIV: Germinal matrix fragmentation
- GV: Germinal matrix avulsion
Sterile Matrix Injury
- SI: Small nail hematoma (50%)
- SII: Sterile matrix laceration, large subungual hematoma (50%)
- SIII: Sterile matrix laceration with tuft fracture
- SIV: Sterile matrix fragmentation
- SV: Sterile matrix avulsion
This classification system is important for determining the appropriate treatment regimen.
Treatment of Fingernail Injuries
Treatment of fingernail injuries depends on the severity of the injury. A radiograph must be obtained to rule out an underlying fracture.
Grade I Fingernail injuries
Grade I injuries are treated nonoperatively in most of the cases. If the injury is very painful, decompression or nail removal can be performed.
Grade II, III, and IV Injuries
All grade II, II and IV injuries require nail removal and repair of the nailbed.
After removal of the nail, debridement of the nailbed is done if required and nailbed is repaired using appropriate sutures.
After repair, the nail is replaced as it serves as a template for the newly growing nail and provides a biologic dressing.
The finger is protected and motion is restricted for 7-10 days.
Nail Bed Avulsion
Nail bed avulsions account for approximately 15% of all traumatic injuries to the nail. For treatment, the avulsed nail bed is sutured in an anatomic position. If the avulsed nail cannot be sutured back, a split-thickness nail matrix graft can be used.
Nail Abnormalities After Trauma
Nail bed injuries can lead to a number of nail abnormalities. Commonly encountered nail deformities are nonadherence, split nails, linear ridging, crooked nails, and hooked nails.
Nonadherence occurs when the nail does not adhere to the abnormal scar that has formed within the injured nail bed.
Nonadherence is the most common nail deformity after nailbed injury. It could be distal nonadherence or proximal one.
Distal nonadherence can cause a problem of dirt being lodged underneath the nail.
Proximal nonadherence can cause instability of the nail.
Treatment is by scar excision and primary repair. Split-thickness nail grafting may be done where required.
Split nails occur because of a longitudinal scar in the germinal or sterile matrix. The nail, therefore, grows on either side of the scar in the germinal matrix.
Treatment is done by scar excision and replacement with a split-thickness matrix graft.
A split nail due to an abnormality in the germinal matrix requires a germinal matrix graft from another finger or toe.
Linear ridging is often secondary to a bony protuberance beneath the nail bed.
Incising the nail bed over the involved area, removal of protruding bone and reapproximation of the nailbed is the treatment performed.
Full-thickness avulsion of the lateral aspect of the nail bed causes the deviation of the nail. Elevation of the entire nail bed and placing it in a straight position is the recommended treatment.
A hooked nail involves volar displacement of the distal aspect of the nail. It can occur following a malunited fracture or a deficiency of skin of the digital pulp.
It is treated by freeing the tethered pulp and nail bed, splinting the freed nail bed, and reconstructing the soft-tissue defect of the pulp.
Total Nail Loss
Total nail loss can be treated by split-thickness skin grafting, nail prosthesis, or total nail reconstruction.