Hand and Wrist Injuries in the Pediatric Athlete

This article examines the most common problematic hand and wrist injuries in the pediatric athlete. Hand and wrist injuries in the growing skeleton pose a different diagnostic and therapeutic challenge than in the mature skeleton. Ligaments are stronger than bone, and unossified cartilaginous sections of the skeleton are yet more susceptible to injury than bone. Although remodeling can correct for even moderate deformities if sufficient growth potential exists, remodeling cannot return the child to normal anatomy in many cases. Remodeling depends on intact periosteum, a nearby growing physis, and competent ligaments to direct remodeling via Hueter-Volkmann and Wolff’s laws.

Key points

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Children are increasingly susceptible to adult-type injuries as their sports participation intensifies.
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Intra-articular fractures are unlikely to remodel to within acceptable parameters, and should merit an anatomic or nearly anatomic reduction with stable fixation whenever possible.
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Avoid crossing the physes with anything other than a smooth pin, and avoid multiple passes with the pin.
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Intraphyseal fractures warrant an anatomic reduction within 7 days whenever possible.

Introduction

Gone are the days when children were allowed free play to develop their motor skills at their own pace. Today, children are being encouraged or even pushed to pursue sports at higher and higher levels at younger and younger ages. As a result, adult-type injuries have become the norm in the pediatric population. One example is scaphoid fractures, which a few decades ago were rare and mostly limited to the distal pole, but are now being seen more frequently and in the same configurations as adult injuries.

The increasing rate of adult-type injuries are in addition to the pediatric-specific injuries more commonly seen, such as physeal injuries and ligamentous avulsions. Children are not just small adults. The growth plate serves as a stress riser in the distal radius and ulna, resulting in injuries that can impact overall growth, joint alignment, and/or differential ulnar/radial length. Ligamentous injuries in children usually present as avulsion injuries rather than midsubstance tears. Special attention should be given to understanding the soft tissue attachments of any bony fleck seen on radiographs. In very young children with incompletely ossified epiphyses and carpal bones, avulsions may be purely cartilaginous, making radiographic diagnosis without an MRI or ultrasound impossible. Radiographs weeks to years later may reveal the true extent of the injury as the cartilaginous avulsion ossifies.

There is a bias among orthopedic surgeons to undertreat fractures in children, with the common refrain that “it will just remodel.” There is an almost magical belief in the power of a child to erase any evidence of traumatic insult. However, joint dislocations and subluxations do not remodel. Ligamentous injuries likewise do not remodel. It is precisely those ligamentous and soft tissue attachments that may help to guide bony remodeling, and their loss can lead to worsening deformity as the child grows. Galeazzi fractures have been seen that worsen, rather than improve over time because the distal radius becomes untethered from and grows independent of the distal ulna ( Fig. 1 ).

Remodeling occurs by two methods: periosteal remodeling and physeal, or Hueter-Volkmann, remodeling ( Fig. 2 ). Periosteal remodeling allows straightening of the bone by laying down bone in the gap created by elevated periosteum, while removing bone where the bone no longer sees compressive load. This occurs in response to Wolff’s law. Periosteal remodeling does nothing to change where the joint is in space; however. Hueter-Volkmann remodeling occurs at the physis because of the enhanced growth of a partially offloaded physis and the restricted growth of a partially overloaded physis. Ligamentous/tendinous tethering and joint motion work in concert to steer the joint back to where it was in space relative to the native axis of the bone. Lack of motion or, in the case of the wrist, disruption of the triangular fibrocartilage complex (TFCC) can minimize remodeling.

This review examines the most common problematic hand and wrist injuries in pediatric athletes. Special emphasis is placed not on just returning children to their sport quickly, but also on the long-term effects of their injuries and treatment on the long-term life goals of the child.

Finger and thumb injuries

Finger and thumb fractures, sprains, and dislocations most commonly occur in ball sports, but is seen in nearly all contact and noncontact sports. Finger proximal interphalangeal (PIP) joint sprains are perhaps the most common, often from a direct blow with another athlete, the ground, or a ball. The long finger is the most exposed and therefore the most likely to be injured. Examination of the PIP joints is fairly straightforward: (1) radiographs should always be obtained with any PIP joint injury before physical examination because fractures and sprains can look identical clinically, (2) the collateral ligaments and the volar plate should be tested gently for competence, and (3) the integrity of the central slip should be assessed with an Elson test. If there is no fracture and the ligaments and tendons are intact, we buddy tape or strap the injured to its adjacent digit and begin early motion with no period of immobilization to prevent contractures. Ligament injuries require immobilization for up to 4 weeks. Central slip avulsions require at least 6 weeks of immobilization in PIP joint extension with the distal interphalangeal joint free. We use low-temperature plastic to quickly manufacture the splint in the office without the need for a therapist ( Fig. 3 ).

Sprains of the distal interphalangeal joint are examined and treated in like manner, with the exception that the terminal tendon replaces the central slip. Acute mallet fractures and deformities without a fracture are treated equally. Late-presenting mallet deformities are also commonly well-managed with just immobilization. Late-presenting fractures require a takedown of the malunion site and pinning if the deformity is not tolerated.

The most common type II phalangeal neck fractures ( Fig. 4 ) are most easily treated using the Strauch technique ( Fig. 5 ) ( https://youtu.be/2ADhL2AOYMU ). In their series of four patients, all regained near full painless motion. We attempt an osteoclasis for late injuries up to 2 weeks old or if they remain tender and painful ( Fig. 6 ). Older injuries are effectively healed and are mobilized after 4 weeks from injury. There is evidence that malunions remodel if more than 2 years of growth remain. All eight patients in one study regained full motion after 1 year. Although the sagittal deformities completely remodeled in all patients, coronal deformities showed less remodeling potential, correcting only 7° on average.

Intercondylar fractures are nearly always unstable and require fixation. Open treatment is risky because of the high risk of avascular necrosis of the condyles. Closed reduction and pinning is therefore recommended. A towel clamp or pointed reduction forceps is applied above the midaxial line to effect a reduction while minimizing neurovascular injury risk. Fingertrap traction also is helpful. There should be a minimum of two Kirschner (K)-wires in each fragment to maintain reduction. Intercondylar fragment rotation is difficult to correct but we are willing to accept slight intercondylar malrotation provided that there is no overall malrotation of the digit and that the middle phalanx articulation is supported by the condyles and will not collapse into either varus or valgus.

Fracture of the base of the proximal phalanx, including extraoctave fractures of the small finger, is managed with closed reduction and splinting, but there is a risk of loss of reduction that is difficult to monitor with radiographs in the splint/cast. We therefore treat all complete fractures at the base of the proximal phalanx with closed reduction and pinning.

Diaphyseal fractures in the hand often present with minimal angulation, displacement, or rotational deformity. More angular deformity is tolerated in children younger than 8 years of age, with up to 30° in the fingers and 45° in the hand in the coronal plane. In older children, 20° is acceptable in the fingers and 30° in the hand. Sagittal plane deformities of more than 5° to 10° are unlikely to remodel. Shortening of up to 5 mm is also acceptable at any age. Rotational deformities are not well tolerated and do not remodel. Phalangeal and metacarpal shaft fractures outside of acceptable parameters are best treated with closed reduction and pinning whenever possible. However, we always consent for open reduction and internal fixation, because reduction by closed means is not possible in all fractures. Care needs to be taken not to dissect through the perichondral ring or to otherwise damage or cross the physis. We use interfragmentary screws for long oblique or spiral fractures and small plates for transverse or short oblique fractures ( Fig. 7 ). Metacarpal neck fractures, including boxer’s fractures, are treated using the same criteria as adults, because these commonly occur near skeletal maturity. We prefer a single pin through the head and the physis and down the shaft ( Fig. 8 ).

An often missed injury is the Seymour fracture, a physeal fracture of the distal phalanx ( Fig. 9 ). Given that the nail plate and bed are the only barriers to the distal phalanx, any displacement of the nail plate that accompanies displacement or angulation of the distal fragment results in an open fracture. The nail bed and nail plate fragments can become interposed, leading to difficulty with reduction. Emergent irrigation and debridement is required as for any other open fracture. The nail bed needs to be tucked back under the eponychial fold. Pinning is optional, depending on stability after debridement. Delays in treatment risk malunion with permanent nail plate deformity, osteomyelitis, and in severe cases amputation. Subacute treatment includes nail plate removal, extrication of debris within the fracture, open reduction, wound culture followed by antibiotics, and stabilization of the fracture.

Thumb metacarpophalangeal joint injuries in a child usually manifest as avulsions of the ligament insertion onto the epiphysis of the proximal phalanx ( Fig. 10 ). These are most commonly seen in skiers and football players. Any displacement of more than a few millimeters or rotation of the fragment can lead to long-term instability of the joint. The fragment tends to be larger than what is visible on radiographs and can make up a sizable percentage of the articular surface. We therefore opt for open reduction and fixation of the bony fragment in most cases. The approach is equivalent to the approach in adults for a metacarpophalangeal collateral ligament injury. Branches of the radial sensory nerve always cross the field and can lead to a painful neuroma if overly retracted or cut. The fragment is reduced and fixed either with a K-wire, a small transepiphyseal screw (that does not cross the physis), or a suture anchor in the epiphysis. Depending on fixation, 4 to 6 weeks of postoperative immobilization is suggested.

Scaphoid fractures

The scaphoid is not fully ossified until approximately 15 years of age. It is the fifth carpal bone to begin to ossify, at between 4 and 6 years of age. The ossification center is distal, and ossification is retrograde following the blood supply. Fractures of the waist and proximal pole are therefore unlikely, and even less likely to be detected, before 8 years of age. The so-called “bipartite” scaphoid ( Fig. 11 ) has been previously described, and is a normal anatomic variant (Dormans). The true atraumatic bipartite scaphoid is likely to be bilateral. A unilateral bipartite scaphoid may be the result of a cartilaginous fracture that went on to a nonunion, but this remains controversial. Regardless of congenital or traumatic cause, the bipartite scaphoid may not be a benign finding. Degenerative changes analogous to a scaphoid nonunion advanced collapse have been reported.