Digital lacerations frequently require special attention. Nail bed injuries often accompany digital fractures. Clinical signs such as bleeding from the eponychium and a laceration proximal to the nail bed suggest a possible open fracture.35 Nail bed lacerations place the underlying bone at risk for bacterial contamination because the skin is directly attached to the periosteum with no intervening layer of subcutaneous tissue. Missed open fractures have resulted in osteomyelitis and growth delay of the digit in children. Consider removal of the nail to evaluate for nail bed laceration if a subungual hematoma occupies a large portion of the nail plate or if there is disruption of the nail or nail folds.36 Repair the nail bed with either absorbable sutures or tissue adhesives.37 Nail bed lacerations are considered to be open fractures of the distal phalanx, so prophylactic antibiotics are recommended.35 Conversely, simple nail trephination is adequate for drainage of subungual hematomas without nail or nail fold deformities.
Tendon injuries of the digits may require consultation, especially when the extensor hallucis longus is involved, because injury to this tendon impairs functionality during the swing phase of the gait cycle. Surgery is often recommended for patients with extensor hallucis longus tendon lacerations, and grafting may be needed.38,39
Lacerations between the toes are difficult to repair because the confined interdigital space is difficult to access for suturing. An assistant gently separating the toes enhances the exploration and repair of interdigital lacerations. Simple interrupted sutures often lead to skin inversion and risk of failure of the initial wound repair with interdigital lacerations. The more effective closure technique, albeit somewhat more difficult to perform, is to place horizontal or vertical mattress sutures. Use 5-0 monofilament nonabsorbable sutures on a small cutting needle. Use monofilament absorbable sutures in young children, thus avoiding suture removal. When a web space laceration involves the neurovascular bundle, the skin is usually closed without attempting to repair the neurovascular injury, followed by subsequent referral to a specialist.
HAIR-THREAD TOURNIQUET SYNDROME
Hair-thread tourniquet syndrome, also referred to as acquired constriction ring syndrome, is an unusual type of toe injury usually seen during infancy40 and rarely seen in older children.41 A long strand of hair or thread becomes wrapped around a toe, often producing strangulation and digital ischemia. This can be an occult source of irritability for infants.40 Complete removal is required to restore perfusion and allow skin healing. Two standard approaches to salvage the compromised digit are to either unwind the hair or thread if possible or, otherwise, make a midline longitudinal incision along the extensor surface of the toe to cut the hair or thread.42 To cut the hair, it will often be necessary to split the fibers of the extensor ligament, but avoid transecting the fibers. The multiple strands of hair or thread are then removed using fine forceps without teeth. The toe often retains the initial appearance, making the physician uncertain whether all of the strands have been removed or cut. A novel but unvalidated method is to apply hair-dissolving compounds.43 Hair-thread tourniquet syndrome can cause deep cutaneous lacerations that result in tendon lacerations requiring operative repair.44 Hair-thread tourniquet syndrome is not the result of intentional injury and does not warrant reporting as suspected child abuse.45
Repairing a laceration on the plantar surface is best done with the patient placed in a prone position, with the foot overhanging the cart or elevated by placing a pillow beneath the ankle. A large suture needle with thick thread is required to penetrate the hypertrophied epidermis and dermis of the sole of the foot. If there is tissue loss or the site is under tension, vertical mattress sutures may be required. In the arch area, achieving tissue eversion can be difficult. Do not use adhesive tapes, tissue adhesives, and staples on the plantar surface. Small or superficial wounds to the plantar surface typically heal rapidly without sutures. Repair small plantar lacerations if the wound gapes open or there is a risk for infection.
DORSAL FOOT AND ANKLE LACERATIONS
Dorsal surface lacerations are repaired almost exclusively with nonabsorbable, monofilament suture material, most commonly 4-0 or 5-0 for small lacerations. Use careful technique suturing the skin to avoid vessels, nerves, and tendons that lie just under the surface. Deep sutures are not recommended for the same reason. Running sutures are acceptable on the dorsal surface, and smaller lacerations may be closed with adhesive tapes or tissue adhesives. For lacerations under tension, consider applying a splint to restrict movement, allowing for healing during the first 5 to 7 days.
The decision to repair tendon lacerations in the foot depends on the functional impairment caused by the injury compared with the benefits of repair. Many extensor tendon lacerations involving the mid-foot and forefoot can go unrepaired without compromising foot function. The skin is closed and the foot splinted, leaving the injured tendon alone. Lacerations of the extensor hallucis longus or tibialis anterior require consultation with an orthopedist or podiatrist because dorsiflexion of the great toe and foot are important in walking and running.39,46 Closure without tendon suturing and with immediate mobilization is acceptable in patients with partial lacerations of the extensor hallucis longus tendon.39
Flexor tendon lacerations across the toes (excluding the great toe) can usually be left unrepaired without significant functional sequelae, but occasionally a hammer toe or claw toe deformity develops. Lacerations of the flexor hallucis longus are frequently repaired, although long-term benefit is unproven, even in athletes.46