39 Pediatric Hand Trauma
Hand trauma in children typically results from sports and play. Compared to adults, children experience less stiffness and better nerve regeneration. Immobilization is often important following operative intervention to ensure the most favorable outcome.
The surgeon’s approach to hand trauma in children should be different from hand trauma in adults. The mechanism of injury, anatomy, healing, and psychosocial concerns of a child require special attention. As opposed to adults, injuries in children vary substantially by age. Young children usually present with “injuries of curiosity”—such as those inflicted by handling broken glass or inserting a finger in the spokes of a spinning bicycle wheel. Older children and adolescents sustain hand injuries from sports and play. Luckily, large industrial hand injuries are rarely seen in children.
Children are usually free of significant medical comorbidities, and thus heal better and faster. Stiffness is unusual, so it is easier for the surgeon to balance healing with commencement of activities. Children regenerate nerves better and rarely develop painful neuromata or pain syndromes. However, in children the important hand structures are small and there is little margin for technical error. Diagnosis can be difficult in a young child or uncooperative adolescent. The surgeon has to respect growth and change over time. In more severe injuries, the surgeon may need to spend significant time counseling the parents and dealing with psychosocial issues. Lastly, there are a number of unusual injury variants in children that if misdiagnosed or mistreated can lead to substantial morbidity.
Adequate immobilization is crucial for treating children with hand injuries. Pain usually subsides several days after injury and children are likely to resume their usual activities if they are not held back. Inadequate immobilization is usually the main culprit in malunions, dehisced wounds, and tendon ruptures. Because stiffness is rarely a problem, there is very little downside to adequate immobilization.
Observation, physical examination, and plain radiography are the main diagnostic tools. In an uncooperative, anxious, or hysterical child, observation is sometimes the most important factor. The importance of distal examination cannot be overemphasized. Exploring a child’s hand or forearm in the emergency department to ascertain for presence of injury is difficult and dangerous. A more gentle approach to examination, such as by recruiting the help of a child life specialist or touch pad game to distract the child, is usually much more effective than brute force. The most difficult injuries to diagnose are flexor tendon and digital nerve injuries in infants and young toddlers, even 5 to 7 days postinjury. Repairing an old flexor tendon injury in a child is very difficult, so exploration is warranted if there is any suspicion.
Plain radiographs usually detect most fractures and dislocations, with the notable exception of acute nondisplaced scaphoid fractures. Ultrasound is instrumental in detecting vascular injury, or more commonly, foreign bodies—especially wood. Computed tomography or magnetic resonance imaging is rarely needed.
In the skeletally immature patient, the ligaments are stronger than bones. Accordingly, it is rare to see ligamentous injury and more common to see fractures. Fractures occur in weak areas of the metaphysis, physis (growth plate), and epiphysis, and result in predictable injury patterns, outlined in the Salter–Harris classification. The most common hand fracture is a proximal phalangeal fracture with a Salter–Harris type II configuration, usually caused by a deviating force (Fig. 39‑1).
Most pediatric hand fractures are nondisplaced or minimally displaced and only require immobilization for 2 to 3 weeks, followed by slow return to normal activity. Most displaced fractures can be reduced in the emergency room (ER) or the operating room under local block, sedation, or general anesthesia. Unstable fractures are usually treated with closed reduction and percutaneous pinning. An open approach is rarely needed.
Fracture remodeling in children can and does occur (Fig. 39‑2). The closer a fracture is to the physis and the younger the patient, the higher is the remodeling potential of the fracture. However, caution should be exercised in treating all fractures with the hopes that they will remodel. Severely displaced fractures will not completely remodel, nor will those far away from the physis (e.g., displaced phalangeal condylar neck fractures). As a general rule, deviation of a finger in the plane of motion is tolerated, whereas deviation perpendicular to the plane of motion is not.
Several pediatric fracture variants can be tricky to diagnose or treat; these are outlined below.
39.3.1 Ulnar Collateral Ligament Injury Variant
This injury is analogous to an adult ulnar collateral ligament injury except that the epiphysis breaks, resulting in a Salter–Harris type III injury (Fig. 39‑3). It occurs from a radially directed force in adolescents near skeletal maturity. The ligament is attached to the small bone fragment. An open approach is required through a dorsal incision. The adductor aponeurosis is incised and a dorsal arthrotomy exposes the joint. The bone is reduced with careful re-approximation of the articular surface. One or two 0.035-in wires can be used to fixate the bone. The bone fragment is small, so it is best to get the fixation as good as possible before inserting the pins. A thumb spica cast is applied for 4 weeks. The pins are then removed, gentle therapy commences, and the thumb is protected in a splint for another 2 to 3 weeks.