Incomplete fractures can occur as the malleable nature of pediatric bone can allow deformation of the cortex without complete fracture. Such fractures, referred to as buckle fractures, tend to be stable and can be successfully treated with symptomatic support only.⁴ Despite this, careful evaluation is necessary to rule out severe injuries that require more definitive care.

Swelling and deformity may not be present, thus observation of the child is quite helpful. Does the child use the hand for bimanual tasks or when trying to climb onto the examination table? A wrist that is not painful at rest may become painful when force is applied to it, so the child will display a willingness to use the hand up to a certain amount of force. It is not uncommon for the child to present several days after the fracture when pain has persisted longer than the caregivers would have expected from a minor injury. Visual inspection can reveal deformity, even if the fracture is incomplete. When a child falls on an outstretched hand, if the wrist is extended during the injury, the wrist may appear extended. However, the volar apex of even substantial extension deformity (15°-20°) can be hidden by the abundant volar
soft tissue around the wrist. Conversely, even subtle flexion of the bone may be readily apparent, as the dorsal apex of the deformity is not well hidden by the scant soft tissue coverage dorsally. Soft tissue injury is rare in the setting of a distal radius buckle fracture, but a thorough examination of the skin in the hand and upper extremity should be performed to rule out associated wounds from the fall.

Tenderness to palpation may only be present on the buckled side of the bone: dorsal in extended fractures and volar in flexed fractures. Circumferential tenderness should prompt concern for a physeal fracture of the distal radius. This injury requires proper orthopedic immobilization and follow-up rather than purely symptomatic treatment. In addition, tenderness should be assessed throughout the extremity, as distal radius buckle fractures can coexist with more proximal fractures, such as a supracondylar humerus fracture.

Complete fractures of the distal radius that do not involve the physis are also common and usually have greater degrees of swelling and deformity. Additionally, the child will be more reluctant to use the hand than in the case of an incomplete fracture. Complete distal radius fractures also commonly involve the distal ulna as well, so tenderness at the ulna is frequently present. In addition, wrist pain with rotation of the forearm is common, given the typical involvement of both forearm bones. A thorough soft tissue examination is important to rule out open fractures.

When a distal radius fracture is suspected, it is important to obtain an anteroposterior and lateral radiograph centered at the wrist. Radiographic images are generated from a single point source of radiation that spreads out as a cone shape through the tissue onto the film. Bone at the center of the film is accurately characterized by the perpendicular radiation; bone at the periphery is distorted by the oblique radiation. Sometimes forearm radiographs (which are focused on the forearm) must be obtained to locate the fracture, especially in young children who cannot locate the pain. However, a radiograph that is not centered at the level of the injury will not fully characterize the amount of displacement. As a result, angulation of a distal radius fracture may be underappreciated on radiographs of the entire forearm.

Key Point: It is important that the joints proximal and distal to a fracture are examined and radiographed as injuries at these areas are common and could be overlooked by the more displaced injury. Regardless, radiographic identification of any complete fracture of the distal radius and/or ulna requires orthopedic referral for further evaluation and definitive management.

The physis of the distal radius is frequently injured, and displaced fractures have a 5% risk of causing a growth disturbance and potentially require corrective surgery.⁵ Prompt identification of significantly displaced physeal injury is important to optimize outcome. Delay of reduction beyond 7 days can increase the risk of subsequent growth arrest, so prompt referral is of paramount importance.

A variable amount of swelling, visible volar ecchymosis, and deformity may indicate significant displacement of the physeal fracture. Less displaced fractures may not be initially swollen, and circumferential tenderness around the physis is the key physical examination finding especially in nondisplaced fractures with normal radiographs. Lister tubercle is a helpful landmark to locate the distal radius physis dorsally (Figure 19.1). Radiographs should be obtained in any child with tenderness around the growth plate. Referral to an orthopedic specialist is necessary even if the radiographs are normal.

Growth plate injuries at the radius may be a result of a high energy mechanism and thus vigilance is needed to detect other problems. Significant displacement can lead to open fracture of the radius or distal ulna and thus antibiotics and surgical treatment are needed to prevent infection. Any pinhole lesions that are adjacent to fracture are considered open until proven otherwise. A distal radius physeal fracture with substantial dorsal displacement can stretch or compress the median nerve as it enters the carpal tunnel; a compromised nerve should prompt emergent reduction of the fracture. Affected median nerves can have decreased sensation in the volar aspect of the thumb, index, middle, and radial side of the ring finger, as well as the radial aspect of the palm. While some of the intrinsic hand muscles
can be affected by median nerve injury, detection of abnormal sensation is more reliable. As with any wrist injury, the remainder of the upper limb should be examined for tenderness and ipsilateral injury.

The scaphoid is the most commonly fractured carpal bone. Injuries typically occur in adolescents, with a peak incidence of 15 years,⁶ and are quite rare in children under 10 years of age. Several complications can arise after fractures of the scaphoid; thus, proper alignment and healing are essential for long-term function of the wrist. To complicate matters, occult fractures may not be detected by radiographs for several weeks after the injury. Even when the diagnosis is made properly, proximal fractures rarely heal without surgery. More distal fractures heal in >90% of cases, but the average time to heal in this location is 9 weeks.⁶ Finally, fractures of the scaphoid in adolescents frequently present as established nonunions where surgery and prolonged immobilization are required to achieve healing.

Any mechanism capable of causing a distal radius fracture can also cause a scaphoid fracture, so a scaphoid fracture should be on the differential diagnosis in such injuries. Swelling is rarely present and associated subcutaneous soft tissue injury is rare. The classic hallmark is tenderness in the anatomic snuffbox (Figure 19.2). It is important to differentiate between snuffbox tenderness and distal radius tenderness, because scaphoid and distal radius fractures can coexist. Have the patient actively extend the thumb to make the extensor pollicis longus and extensor pollicis brevis tendons prominent; the snuffbox sits in the hollow between these two tendons. Two additional pearls are helpful in differentiating between snuffbox and physeal tenderness. First, ask the patient which site is more tender. A scaphoid fracture is suspected if the snuffbox is more tender than the distal radius. Second, ask the patient “if you had to put a ball point pen dot on the spot that your wrist hurts the most, where would you put that dot?” Patients with scaphoid fractures typically point to the radial side of their wrist, whereas patients with distal radius fractures point to the dorsal side of their wrist.

These fractures typically are also tender at the distal pole of the scaphoid, which is palpable as a prominence at the radial side of the wrist flexion crease. Finally, scaphoid fractures typically cause radial-sided wrist pain with passive radial deviation of the wrist. The presence of these three findings (snuffbox tenderness, scaphoid tubercle tenderness, and radial-sided wrist pain with passive radial deviation of the wrist) should raise concern for the provisional diagnosis of a scaphoid fracture until proven otherwise.

Plain radiographs including a posteroanterior (PA), lateral wrist, and scaphoid view (PA radiograph in ulnar deviation) should be obtained. The latter view allows better identification of a fracture as ulnar deviation extends the scaphoid into view. Yet a fracture should still be suspected if the exam is positive and the radiographs are negative. At this point, the wrist can be immobilized with repeat radiographs obtained at weekly or bi-weekly intervals. However, only 85% of initially occult fractures have positive radiographs within 5 weeks of injury. Alternatively, magnetic resonance imaging (MRI) can be obtained, which will identify fractures within 24 hours of injury with high sensitivity.

Once the diagnosis of a scaphoid fracture is made, referral to an orthopedist is required and treatment may consist of cast immobilization until healed or surgery based upon location, the displacement, and the chronicity.

The triangular fibrocartilage complex (TFCC) cushions the articulation between the ulna and the carpus, and it stabilizes the articulation between the radius and the ulna via dorsal and volar radioulnar ligaments that originate from the base of the ulnar styloid and insert onto the dorsal and volar rim of the distal radius. Most injuries of the TFCC follow an acute injury⁷ such as a hyper-twisting injury to the forearm, a fall or excessively forceful lifting. Additionally, TFCC tears can coexist with displaced distal radius fractures, especially when such fractures include a fracture of the ulnar styloid. Sometimes, a discrete injury is not known, and symptoms from a TFFC tear can appear insidiously.

Typically, patients with TFCC tears can very precisely localize pain on the ulnar side of the wrist, most focally in the soft spot just distal to the distal ulna (the ulnar fovea, Figure 19.3). Additionally, ulnar-sided wrist pain with active and/or passive forearm supination is quite specific for TFCC injuries. Other provocative test findings include ulnar-sided pain with gripping or with dorsal/volar translation of the distal radioulnar joint (DRUJ).⁸

Radiographs of the wrist should be obtained to rule out injuries that can mimic or coexist with a TFCC tear, such as an ulnar styloid fracture or dorsal avulsion fracture from the triquetrum. MRI has relatively poor accuracy for diagnosing TFCC tears. Arthroscopic surgical evaluation of the TFCC is the only method for making a definitive diagnosis in the rare patient who does not heal with immobilization in a long arm cast (to prevent forearm rotation) and subsequent therapy.

Injuries of the ligaments connecting the carpal bones are uncommon in children, although they can occur in adolescents from high-energy hyperextension
injury. Two versions require specific mention as they can cause substantial loss of function: scapholunate interosseous ligament (SLIL) disruption and perilunate dislocation.⁹

The SLIL is a U-shaped array of fibers that connects the scaphoid and the lunate along their dorsal (primary stabilizer), proximal, and volar edges. Complete tearing of these fibers can cause separation of the scaphoid and lunate with progressive collapse of the carpus and subsequent arthritis. Two key physical exam features help to identify this injury and differentiate it from distal radius fractures and scaphoid fractures. First, patients will localize tenderness just distal to the distal radius. Second, the Watson test can elicit pain specific to SLIL injuries ( Video 19.1). In this test, pressure is placed with the thumb volarly on the distal pole of the scaphoid, and the wrist is passively radially deviated. This combination of forces applies stress to the SLIL. If the dorsal fibers of the SLIL are injured, the maneuver will cause dorsal wrist pain, even though no direct pressure is applied dorsally. If the SLIL is completely torn, the maneuver can subluxate the scaphoid and cause a painful clunk when pressure is relieved, akin to the Ortolani and Barlow maneuvers for hip dysplasia. Plain static radiographs are notoriously difficult to utilize in the pediatric wrist suspected of having a scapholunate ligament disruption.¹,¹⁰ Therefore, any clinical suspicion for an SLIL injury should prompt referral to a specialist for further evaluation.

Perilunate dislocations are severe ligamentous injuries to the wrist, typically occurring in adolescents from a high-energy injury involving wrist hyperextension. The short radiolunate ligament, which connects the volar rim of the radius to the volar pole of the lunate, is among the strongest ligaments in the wrist. Therefore, when the wrist is forcefully hyperextended, this ligament keeps the lunate secured against the radius while the remainder of the carpal bones dislocate dorsally around it. In the most severe case, the lunate is pushed volarly out of the radiocarpal joint where it can apply substantial pressure to the median nerve in the carpal tunnel. Unfortunately, due to the normally complex and overlapping anatomy of the carpal bones, these injuries can be missed initially on plain radiographs.

Adolescents with perilunate dislocations have pronounced swelling with limited and painful motion. Median nerve function may not be normal because of stretch of the nerve from the dislocation or pressure on the nerve from a displaced lunate. Proper early identification is important, because emergent reduction is required to relieve pressure on surrounding structures, especially the median nerve. Definitive treatment requires surgical stabilization of the carpus and repair or reconstruction of the torn intercarpal ligaments, along with release of the carpal tunnel when indicated. However, because of the severe nature of this injury, persistent stiffness and dysfunction can often follow appropriate treatment.

The evaluation of the injured metacarpal region of the hand begins with a careful history, as the mechanism of injury can be helpful in assessing the risk of associated severe soft tissue problems.¹¹ Finger and metacarpal fractures commonly occur by axial loading, such as in a fall on a closed fist or in a punching injury. The boxer’s fracture, or fracture of the small finger metacarpal neck, is one of the more common fractures (Figure 19.4). These injuries can include lacerations of the skin overlying the metacarpal head, damaging the extensor tendon and penetrating the metacarpophalangeal (MCP) joint. If the object punched is an opponent’s tooth, oral bacteria can contaminate the MCP joint and lead to septic arthritis. Any full thickness skin injury over the metacarpal heads warrants radiographs to rule out an underlying open fracture. Ruling out joint penetration requires insufflation of the joint with sterile saline to
check for egress from the wound, a procedure best done in an emergency department by a qualified specialist. Ruling out extensor tendon injury can be difficult, as the tendon will retract proximal to the wound when the MCP joint is extended. Direct visualization of the tendon through the wound is typically required, again with proper anesthesia and sterile technique.

In young children, crush injuries to the metacarpal region, such as in a gate or industrial door, can cause multiple metacarpal fractures with severe associated soft tissue swelling. Such swelling can progress to compartment syndrome of the hand. The dorsal skin of the hand is very loose and dorsal swelling can be quite dramatic even without a compartment syndrome. However, the palmar skin is firmly anchored to the metacarpals with vertical fibrous septae, so substantial pressure is required to elevate the skin of the palm into a convex shape. Therefore, swelling with a convex palm should raise suspicion for actual or impending compartment syndrome (Figure 19.5). If a compartment syndrome is suspected or the child is at risk for developing one, referral to a specialist and inpatient admission may be warranted to allow close observation, as swelling can peak in the first 24 to 48 hours after injury. Immediate surgical compartment release, within 6 hours of the compartment syndrome, is required to prevent tissue necrosis and permanent dysfunction.

Beyond examining for associated soft tissue injuries, careful examination for rotational malalignment is critical, especially in the finger metacarpals. Only physical examination will reliably identify the rotational displacement as fractures may appear to be nondisplaced on radiographs. Flexion of the MCP joints will reveal overlapping of fingers when a severe rotational deformity is present (Figure 19.6). Comparing to the opposite hand is helpful to identify less significant malalignment seen as subtle convergence or divergence of fingers. In the young and/or apprehensive child, finger flexion can be achieved by passive extension of the wrist that generates tension in the finger flexor tendons. Pronating the forearm during this maneuver will add the force of gravity to the effect of tenodesis flexing the fingers, requiring the patient to actively extend the fingers to resist finger flexion.

Fractures at the base of the metacarpals can be associated with injuries of the carpometacarpal (CMC) joints. These dislocations or joint malalignments can be difficult to identify on plain radiographs because of the overlapping metacarpals and the arch of the carpus. On physical examination, dorsal prominence of the metacarpal bases can be seen and/or palpated. In the thumb, CMC dislocation can cause a swan neck deformity due to the compensatory hyperextension of the MCP joint. Any deformity noted in the region of the CMC joints should warrant additional imaging such as computed tomography to aid in treatment planning.

MCP dislocation is nearly always a dorsal dislocation. Physical examination for this injury is critical as it can be missed on radiographs. Because of the swelling that rapidly occurs dorsally, the injury may not be associated with obvious deformity other than resting hypertension of the digit (Figure 19.7). Palpation in the palm may identify a prominent metacarpal head, and even tented, puckered, or ischemic overlying skin. A neurologic examination is critical, as the dislocation can cause injury to the digital nerves stretched over the volarly
prominent metacarpal head. Prompt reduction is required, emergently if neurologic compromise or skin ischemia is present; up to 50% of dislocations will require surgical reduction.

MCP ligament injuries of the thumb are also diagnosed clinically. Knowing the direction of displacement of the thumb can help to determine the injured structure. A pure hyperextension injury causes a volar plate rupture with volar tenderness and swelling throughout the thenar eminence. A radial deviation injury typically injures the ulnar collateral ligament, which tends to avulse from the insertion at the base of the proximal phalanx. The joint will be tender ulnarly and swelling will be present in the first web space. Passive radial deviation of the thumb in 30° of flexion will produce ulnar-sided pain and may reveal instability of the thumb when compared to the contralateral side. With sufficient displacement, the adductor aponeurosis may be interposed and the ulnar collateral ligament may be palpable beneath the skin in the first web space, the so-called Stener lesion. In adolescents, similar injuries may be seen as displaced, intra-articular avulsion fractures from the base of the proximal phalanx by the ulnar collateral ligament. Therefore, radiographs of injured thumb MCP joints are always warranted.

A hyperflexion or ulnar deviation injury of the thumb typically injures the radial collateral ligament, which typically avulses from the origin on the metacarpal head. Tenderness and focal swelling will be present at the dorsoradial aspect of the metacarpal head, and radial-sided pain will be reproduced with passive flexion and/or ulnar deviation. Fortunately, most thumb MCP ligament injuries are incomplete and can heal reliably with conservative management; operative treatment is reserved for a Stener lesion, substantial laxity, displaced fractures, or a failed conservative treatment.

The most important finger MCP collateral ligament is the radial collateral ligament of the index finger that resists force applied during pinch. Since the collateral ligaments of the finger MCP joints
are lax in extension but taut in flexion, stability should be assessed by flexing the MCP joint maximally and applying deviation stress ( Video 19.2). Treatment of finger collateral ligament injuries typically involves protected early motion, as stiffness tends to be a more troublesome outcome than persistent instability, in contrast to the thumb MCP joint. Regardless of the ligament injured and the digit involved, radiographs should always be obtained, as intra-articular fractures at the origin or insertion of the collateral ligaments are typically more common than isolated ligament injuries in children and adolescents.

Phalanx fractures are among the most common injuries in children¹² and can cause permanent dysfunction if treatment is not appropriate and timely. All too often, patients with finger injuries will be brought for medical attention after several weeks when the “jammed” digit does not improve. Radiographs should be obtained if any deformity is present or delayed-onset ecchymosis (2-3 days later) occurs. Radiographs should be isolated to each injured finger with separate lateral radiographs of each finger, as overlapping fingers will hide subtle injuries.