Fracture type and degree of displacement is also dependent on the height and velocity of the fall or injury mechanism.212 Indeed, the spectrum of injury may range from nondisplaced torus (or “buckle”) injuries (common in younger children with a minimal fall) or dorsally displaced fractures with apex volar angulation (more common in older children with higher-velocity injuries (Fig. 11-1). Displacement may be severe enough to cause foreshortening and bayonet apposition. Rarely, a mechanism such as a fall from a height can cause a distal radial fracture associated with a more proximal fracture of the forearm or elbow (Fig. 11-3).12,171 These “floating elbow’’ situations connote higher-energy trauma and as a result are associated with risks of neurovascular compromise and compartment syndrome.12,171
Fractures of the distal forearm in children typically occur when the radius and/or ulna are more susceptible to fracture secondary to biomechanical changes during skeletal development. Recent work based upon load-to-strength ratio and other measures of bone quality have identified specific times during skeletal development where the biologic properties of the distal upper extremity produce relatively weaker bone, making a child more susceptible to fracture.65,109,118,145 In these studies, prepubescent boys and girls were found to have lower estimates of bone strength compared to same sex postpubertal peers. From these studies, it can be concluded that children are uniquely susceptible for fracture when longitudinal growth outpaces mineral accrual during rapid growth.13 As 90% of the radius growth is from the distal physis and accounts for 70% of the loading across the wrist, the radius is more prone to fracture than the ulna during rapid growth.200 Fractures occur at the biomechanically weakest anatomic location of bone, which also varies over time. As the metaphyseal cortex of the radius is relatively thin and porous fractures in this region are most common, followed by physeal.138,190
Usually, fractures occur during sports-related activities. Indeed, the recent trend toward increased sports participation in children has led to a substantial increase in the incidence of distal radius and/or ulna fractures.102,211 Certain sports, such as skiing/snowboarding, basketball, soccer, football, rollerblading/skating, and hockey have been associated with an increased risk of distal radial fracture, though a fall or injury of sufficient severity may occur in any recreational activity.188 Protective wrist guards have been shown to decrease the injury rate in snowboarders, especially beginners and persons with rental equipment.173
As cited above, there is seasonal variation, with an increase in both incidence and severity of fractures in summer.201 Children who are overweight, have poor postural balance, ligamentous laxity, or less bone mineralization are at increased risk for distal radial fractures.83,117,123,165,180,212 Although bone quality measures predict that boys had lower risk of fracture than girls at every stage except during early puberty,145 these fractures have been reported to be three times more common in boys. However, the increased participation in athletics by girls at a young age may be changing this ratio.
Radial Physeal Stress Fractures
Repetitive axial loading of the wrist may lead to physeal stress injuries, almost always involving the radius (Fig. 11-4). These physeal stress injuries are most commonly seen in competitive gymnasts.29,47,52,191,192 Factors that predispose to this injury include excessive training, poor techniques, and attempts to advance too quickly in competitive level and have been also observed in other sports including wresting, break dancing, and cheerleading.76
Axial loading of the wrist in combination with extremes of forearm rotation (Fig. 11-5) may result in distal radius fractures with associated disruption of the DRUJ, the so-called “pediatric Galeazzi fracture.”26,40,72,122,127,135,199 In adults, the mechanism of injury usually is an axially loading fall with hyperpronation. This results in a distal radial fracture with DRUJ ligament disruption and dorsal dislocation of the ulna. However, in children, both supination (apex volar) and pronation (apex dorsal) deforming forces have been described.126,198 The mechanism of injury is most obvious when the radial fracture is incomplete. With an apex volar (supination) radial fracture, the distal ulna is displaced volarly, whereas with an apex dorsal (pronation) radial fracture, the distal ulna is displaced dorsally. This is evident both on clinical and radiographic examinations. In addition, the radius is foreshortened in a complete fracture, causing more radial deviation of the hand and wrist. In children, this injury may involve either disruption of the DRUJ ligaments or, more commonly, a distal ulnar physeal fracture (Fig. 11-6).1,170
Injuries Associated with Fractures of the Distal Radius and Ulna
The risk of associated injuries is significantly less in the skeletally immature as compared to skeletally mature patients.58 The entire ipsilateral extremity should be carefully examined for fractures of the carpus, forearm, or elbow.12,32,91,120,171,182,193 Indeed, 3% to 13% of distal radial fractures have associated ipsilateral extremity fractures.182 Associated fractures of the hand and elbow regions need to be assessed because their presence implies more severe trauma. For example, the incidence of a compartment syndrome is higher with a “floating elbow’’ combination of radial, ulnar, and elbow fractures.171
With marked radial or ulnar fracture displacement, neurovascular compromise can occur.15,44,203 Median neuropathy may be seen in severely displaced distal radius fractures, due to direct nerve contusion sustained at the time of fracture displacement, persistent pressure or traction from an unreduced fracture, or an acute compartment syndrome (Fig. 11-7).203 Ulnar neuropathy has been described with similar mechanisms, as well as entrapment or incarceration of the ulnar nerve within the fracture site.
Wrist ligamentous and articular cartilage injuries have been described in association with distal radial and ulnar fractures in adults and less commonly in children.12,55 Concomitant scaphoid fractures have occurred (Fig. 11-8).32,41,194 Associated wrist injuries need to be treated both in the acute setting and in the patient with persistent pain after fracture healing. Some patients with distal radial and ulnar fractures are multitrauma victims. Care of the distal forearm fracture in these situations must be provided within the context of concomitant systemic injuries. More than 50% of distal radial physeal fractures have an associated ulnar fracture. This usually is an ulnar styloid fracture, but can be a distal ulnar plastic deformation, greenstick, or complete fracture.33,107,123,190
Isolated ulnar physeal fractures are rare injuries.1,183 Most ulnar physeal fractures occur in association with radial metaphyseal or physeal fractures. Physeal separations are classified by the standard Salter–Harris criteria. The rare pediatric Galeazzi injury usually involves an ulnar physeal fracture rather than a soft tissue disruption of the DRUJ. Another ulnar physeal fracture is an avulsion fracture off the distal aspect of the ulnar styloid.1 Although an ulnar styloid injury is an epiphyseal avulsion, it can be associated with soft tissue injuries of the TFCC and ulnocarpal joint, though does not typically cause growth-related complications.
Signs and Symptoms of Fractures of the Distal Radius and Ulna
Fractures of the Distal Radius and Ulna
Children with distal radial and/or ulnar fractures present with pain, swelling, and deformity of the distal forearm (Fig. 11-9). The clinical signs depend on the degree of fracture displacement. With a nondisplaced torus fracture in a young child, medical attention may not be sought until several days after injury; the intact periosteum and biomechanical stability is protective in these injuries, resulting in minimal pain and guarding. Similarly, many of the physeal injuries are nondisplaced and present only with pain and tenderness at the physis.142,154 With displaced fractures, the typical dorsal displacement and apex volar angulation create an extension deformity that is usually clinically apparent. Careful inspection of the forearm is critical to evaluate for possible skin lacerations, wounds, and open fractures.
With greater displacement, physical examination is often limited by the patient’s pain and anxiety, but it is imperative to obtain an accurate examination of the motor and sensory components of the radial, median, and ulnar nerves before treatment is initiated. Neurovascular compromise is uncommon but can occur.203 A prior prospective study indicated an 8% incidence of nerve injury in children with distal radial fractures.204 Median nerve irritability or dysfunction is most common, caused by direct trauma to the nerve at the time of injury or ongoing ischemic compression from the displaced fracture. Median nerve motor function is evaluated by testing the abductor pollicis brevis (intrinsic) and flexor pollicis longus (extrinsic) muscles. Ulnar nerve motor evaluation includes testing the first dorsal interosseous (intrinsic), abductor digit quinti (intrinsic), and flexor digitorum profundus to the small finger (extrinsic) muscles. Radial nerve evaluation involves testing the common digital extensors for metacarpophalangeal joint extension as well as extensor pollicis longus. Sensibility to light touch and two-point discrimination should be tested. Normal two-point discrimination is less than 5 mm but may not be reliably tested in children younger than 5 to 7 years of age. Pin-prick sensibility testing will only hurt and scare the already anxious child and should be avoided.
Radial Physeal Stress Fracture
In contrast to the child with an acute, traumatic distal radius fracture, patients with distal radial physeal stress injuries typically report recurring, activity-related wrist pain. Characteristically, this pain is described as diffuse “aching” and “soreness” in the region of the distal radial metaphysis and physis. Pain may be reproduced in the extremes of wrist extension and flexion, and usually there is local tenderness over the dorsal, distal radial physis. Resistive strength testing of the wrist extensors will also reproduce the pain. There may be fusiform swelling about the wrist if there is reactive bone formation. The differential diagnosis includes physeal stress injury, ganglion, ligamentous or TFCC injury, tendinosis or musculotendinous strain, carpal fracture, and osteonecrosis of the scaphoid (Preiser disease) or lunate (Kienbock disease). Diagnosis is made radiographically in the context of the clinical presentation.
Children with Galeazzi injuries present with pain, limited forearm rotation, and limited wrist flexion and extension. Neurovascular impairment is rare. The radial deformity usually is clinically evident. Prominence of the ulnar head is seen with DRUJ disruption. Ligamentous disruption is often subtle and may be evident only by local tenderness and instability to testing of the DRUJ.
Imaging and Other Diagnostic Studies Fractures of the Distal Radius and Ulna
Plain radiographs are diagnostic of the fracture type and degree of displacement. Standard anteroposterior (AP) and lateral radiographs usually are sufficient. Complete wrist, forearm, and elbow views are recommended in cases of high-energy injuries or when there is clinical suspicion for an ipsilateral fracture of the hand, wrist, or elbow. More extensive radiographic evaluation (e.g., computed tomography [CT], magnetic resonance imaging [MRI]) is typically reserved for evaluation of suspected or known intra-articular fractures or associated carpal injuries (e.g., scaphoid fractures, hook of hamate fractures, perilunate instability); these situations are most commonly encountered in older adolescents.
There has been increasing enthusiasm for the use of ultrasound in the diagnostic evaluation of distal radius and ulna fractures.28,60,99,142,154,162 Two independent studies have demonstrated the feasibility and accuracy of bedside ultrasound for diagnosing nondisplaced fractures28,162 Ultrasonography is most useful in cases of suspected fractures in the absence of plain radiographic abnormalities, or in very young children in whom the skeletal structures are incompletely ossified.
Radiographic evaluation should be performed not only to confirm the diagnosis but also to quantify the degree of displacement, angulation, malrotation, and comminution (Fig. 11-10). Understanding of the normal radiographic parameters is essential in quantifying displacement. In adults, the normal distal radial inclination averages 22 degrees on the AP view and 11 degrees of volar tilt on the lateral projection.73,137,148,181,220 Radial inclination is a goniometric measurement of the angle between the distal radial articular surface and a line perpendicular to the radial shaft on the AP radiograph. Volar tilt is measured by a line across the distal articular surface and a line perpendicular to the radial shaft on the lateral view. Pediatric values for radial inclination and volar tilt may vary from adult normative values, depending on the degree of skeletal maturity and the ossification of the epiphysis. Indeed, radial inclination is often less than 22 degrees in younger children, though volar tilt tends to be more consistent regardless of patient age.
As noted above, advanced imaging may be helpful in cases of intra-articular extension to characterize fracture pattern and joint congruity. This may be done by AP and lateral tomograms, CT scans, or MRI. Dynamic motion studies with fluoroscopy can provide important information on fracture stability and the success of various treatment options. Dynamic fluoroscopy requires adequate pain relief and has been used more often in adult patients with distal radial fractures.
Radiographs are also diagnostic in cases of suspected distal radial physeal stress injuries. Physeal widening, cystic and sclerotic changes in the metaphyseal aspect of the distal radial physis, beaking of the distal radial epiphysis, and reactive bone formation are highly suggestive of chronic physeal stress fracture. In advanced cases, premature physeal closure or physeal bar formation may be seen, indicating long-standing stress.29,47,52,174,192,213 In these situations, continued ulnar growth leads to an ulnar positive variance with resulting pain from ulnocarpal impaction and/or TFCC tear.12,174,213 Plain radiographs may not reveal early physeal stress fracture. If the diagnosis is suggested clinically, additional studies may be indicated. Technicium bone scanning is sensitive but nonspecific. MRI is usually diagnostic, demonstrating the characteristic “double line” on coronal T1 and gradient echo sequences.128
In Galeazzi fractures, the radial fracture is readily apparent on plain radiographs. Careful systematic evaluation of the radiographs will reveal concurrent injuries to the ulna and/or DRUJ (Fig. 11-11). A true lateral radiograph is essential to identify the direction of displacement and thus to determine the method of reduction. Rarely are advanced imaging studies, such as CT or MRI scan, are necessary.
Classification Fractures of the Distal Radius and Ulna
Distal Radius and Ulna Fractures
Distal radius and ulna fractures are classified according to fracture pattern, type of associated ulnar fracture, and direction of displacement, angulation, and rotation. Most distal radial metaphyseal fractures are displaced dorsally with apex volar angulation.190 Volar displacement with apex dorsal angulation occurs less commonly with volar flexion mechanisms.
Distal radial and ulnar fractures are then defined by their anatomic relationship to the physis. Physeal fractures are classified by the widely accepted Salter–Harris system (see below).27,175 Metaphyseal injuries are often different from their adult equivalents, due to the thick periosteum surrounding the relatively thin metaphyseal cortex. Metaphyseal fractures are generally classified according to fracture pattern and may be torus fractures, greenstick or incomplete fractures, or complete bicortical injuries. Pediatric equivalents of adult Galeazzi fracture-dislocations involve a distal radial fracture and either a soft tissue disruption of the DRUJ or a physeal fracture of the distal ulna (Table 11-1).
TABLE 11-1 Distal Forearm Fractures: General Classification
The Salter–Harris system is the basis for classification of physeal fractures.174 Most are Salter–Harris type II fractures.27 In the more common apex volar injuries, dorsal displacement of the distal epiphysis and the dorsal Thurston–Holland metaphyseal fragment is evident on the lateral view (Fig. 11-12). Salter–Harris type I fractures also usually displace dorsally. Volar displacement of either a Salter–Harris type I or II fracture is less common (Fig. 11-13). Nondisplaced Salter–Harris type I fractures may be indicated only by a displaced pronator fat pad sign (Fig. 11-14),175,218 ultrasound,28,99,153 or tenderness over the involved physis.141,153 A scaphoid fat pad sign may indicate a scaphoid fracture (Fig. 11-15).94
Salter–Harris type III fractures are rare and may be caused by a compression, shear, or avulsion of the radial origin of the volar radiocarpal ligaments (Fig. 11-16).9,125 Triplane equivalent fractures,157 a combination of Salter–Harris type II and III fractures in different planes, have similarly been reported but are rare. CT scans may be necessary to define the fracture pattern and degree of intra-articular displacement.
Metaphyseal fracture patterns are classified as torus, incomplete or greenstick, and complete fractures (Fig. 11-17). This system of classification has been shown to have good agreement between experienced observers.167 Torus fractures are axial compression injuries. The site of cortical failure is the transition from metaphysis to diaphysis.128 As the mode of failure is compression, these injuries are inherently stable and are further stabilized by the intact surrounding periosteum. Rarely, they may extend into the physis, putting them at risk for growth impairment.155,156,158
Incomplete or greenstick fractures occur with a combination of compressive, tensile, and rotatory forces, resulting in complete failure of one cortex and plastic deformation of the other cortex. Most commonly, the combined extension and supination forces lead to tensile failure of the volar cortex and dorsal compression injury. The degree of force determines the amount of plastic deformation, dorsal comminution, and fracture angulation and rotation.
With greater applied loads, complete fracture occurs with disruption of both the volar and dorsal cortices. Length may be maintained with apposition of the proximal and distal fragments. Frequently, the distal fragment lies proximal and dorsal to the proximal fragment in bayonet apposition (Table 11-2).
TABLE 11-2 Classification: Distal Metaphyseal Fractures
Ulnar fractures often associated with radial metaphyseal injuries may occur in the metaphysis, physis, or through the ulnar styloid. Similar to radial metaphyseal fractures, the ulnar fracture can be complete or incomplete. These injuries are also characterized according to fracture pattern and displacement.
Distal radial fractures also can occur in conjunction with more proximal forearm fractures,19,203 Monteggia fracture-dislocations,18 supracondylar distal humeral fractures,170,181 or carpal fractures.32,41,91,119 The combination of a displaced supracondylar distal humeral fracture and a displaced distal radial metaphyseal fracture has been called the pediatric floating elbow. This injury combination is unstable and has an increased risk for malunion and neurovascular compromise.
Distal Ulna Fractures
Isolated ulnar physeal fractures are rare, as most ulnar physeal injuries occur in association with radial metaphyseal or physeal fractures.1,182 Physeal injuries are classified according to the Salter–Harris classification.155 Ulnar physeal fractures may also be seen with the pediatric Galeazzi injuries,169 which usually involve an ulnar physeal fracture rather than a soft tissue disruption of the DRUJ.
Avulsion fractures of the ulnar styloid also represent epiphyseal avulsion injuries. Most commonly associated with distal radial fractures,1,182 these styloid fractures typically represent soft tissue avulsions of the ulnar insertion of the TFCC or ulnocarpal ligaments12 and are rarely associated with growth-related complications.
Galeazzi fracture-dislocations are most commonly described by direction of displacement of either the distal ulnar dislocation or the radial fracture.126 Letts preferred to describe the direction of the ulna: volar or dorsal.77,198 Others classified pediatric Galeazzi injuries by the direction of displacement of the distal radial fracture. Dorsally displaced (apex volar) fractures were more common than volarly displaced (apex dorsal) injuries in their series. Wilkins and O’Brien209 modified the Walsh and McLaren method by classifying radial fractures as incomplete and complete fractures and ulnar injuries as true dislocations versus physeal fractures (Table 11-3). DRUJ dislocations are called true Galeazzi lesions and distal ulnar physeal fractures are called pediatric Galeazzi equivalents.109,121,126
TABLE 11-3 Classification: Galeazzi Fractures in Children
PATHOANATOMY AND APPLIED ANATOMY RELATING TO FRACTURES OF THE DISTAL RADIUS AND ULNA
The distal radial epiphysis normally appears between 0.5 and 2.3 years in boys and 0.4 and 1.7 years in girls.73,147,136 Initially transverse in appearance, it rapidly becomes more adultlike with its triangular shape. The contour of the radial styloid progressively elongates with advancing skeletal maturity. The secondary center of ossification for the distal ulna appears at about age.147 Similar to the radius, the ulnar styloid appears with the adolescent growth spurt. It also becomes more elongated and adultlike until physeal closure. On average, the ulnar physis closes at age 16 in girls and age 17 in boys, whereas the radial physis closes on average 6 months later than the ulnar physis.172,220 The distal radial and ulnar physes contribute approximately 75% to 80% of the growth of the forearm and 40% of the growth of the upper extremity (Fig. 11-18).148
The distal radius articulates with the distal ulna at the DRUJ.177 Both the radius and ulna articulate with the carpus, serving as the platform for the carpus and hand. The radial joint surface has three concavities for its articulations: the scaphoid and lunate fossa for the carpus and the sigmoid notch for the ulnar head. These joints are stabilized by a complex series of volar and dorsal radiocarpal, ulnocarpal, and radioulnar ligaments. The volar ligaments are the major stabilizers. Starting radially at the radial styloid, the radial collateral, radioscaphocapitate, radiolunotriquetral (long radiolunate), and radioscapholunate (short radiolunate) ligaments volarly stabilize the radiocarpal joint. The dorsal radioscaphoid and radial triquetral ligaments are less important stabilizers. The complex structure of ligaments stabilize the radius, ulna, and carpus through the normal wrist motion of 120 degrees of flexion and extension, 50 degrees of radial and ulnar deviation, and 150 degrees of forearm rotation.150
The triangular fibrocartilage complex (TFCC) is the primary stabilizer of the ulnocarpal and radioulnar articulations.150 It extends from the sigmoid notch of the radius across the DRUJ and inserts into the base of the ulnar styloid. It also extends distally as the ulnolunate, ulnotriquetral, and ulnar collateral ligaments and inserts into the ulnar carpus and base of the fifth metacarpal.150 The volar ulnocarpal ligaments (V ligament) from the ulna to the lunate and triquetrum are important ulnocarpal stabilizers.22,178 The central portion of the TFCC is the articular disk (Fig. 11-19). The interaction between the bony articulation and the soft tissue attachments accounts for stability of the DRUJ during pronation and supination.151 At the extremes of rotation, the joint is most stable. The compression loads between the radius and ulna are aided by the tensile loads of the TFCC to maintain stability throughout rotation.
The interosseous ligament of the forearm (Fig. 11-20) helps stabilize the radius and ulna more proximally in the diaphysis of the forearm. The ulna remains relatively immobile as the radius rotates around it. Throughout the midforearm, the interosseous ligament connects the radius to the ulna. It passes obliquely from the proximal radius to the distal ulna. However, the interosseous ligament is not present in the distal radius. Moore et al.140 found that injuries to the TFCC and interosseous ligament were responsible for progressive shortening of the radius with fracture in a cadaveric study. The soft tissue component to the injury is a major factor in the deformity and instability in a Galeazzi fracture-dislocation.
The length relationship between the distal radius and ulna at the wrist is defined as ulnar variance. In adults, this is measured by the relationship of the radial corner of the distal ulnar articular surface to the ulnar corner of the radial articular surface.100 However, measurement of ulnar variance in children requires modifications of this technique. Hafner89 described measuring from the ulnar metaphysis to the radial metaphysis to lessen the measurement inaccuracies related to epiphyseal size and shape, a technique recently validated by Goldfarb (Fig. 11-21).80 If the ulna and radius are of equal lengths, there is a neutral variance. If the ulna is longer, there is a positive variance. If the ulna is shorter, there is a negative variance. Variance measurement is usually made in millimeters.
Although not dependent on the length of the ulnar styloid,22 the measurement of ulnar variance is dependent on forearm position and radiographic technique.61 Radiographs of the wrist to determine ulnar variance should be standardized with the hand and wrist placed on the cassette, with the shoulder abducted 90 degrees, elbow flexed 90 degrees, and forearm in neutral rotation (Fig. 11-22). The importance of ulnar variance relates to the force transmission across the wrist with axial loading. Normally, the radiocarpal joint bears approximately 80% of the axial load across the wrist, and the ulnocarpal joint bears 20%. Changes in the length relationship of the radius and ulna alter respective load bearing. Indeed, 2.5 mm of ulnar positive variance has been demonstrated to double the forces borne across the ulnocarpal articulation in adult biomechanical analyses.105,151 Biomechanical and clinical studies have shown that this load distribution is important in fractures, TFCC tears (positive ulnar variance), and Kienbock disease (negative ulnar variance).4,75
The distal radius normally rotates around the relatively stationary ulna. The two bones of the forearm articulate at the proximal radioulnar joints and DRUJs. In addition, proximally the radius and ulna articulate with the distal humerus and distally with the carpus. These articulations are necessary for forearm pronation and supination. At the DRUJ, the concave sigmoid notch of the radius incompletely matches the convex, asymmetric, semicylindrical shape of the distal ulnar head.22,151 This allows some translation at the DRUJ with rotatory movements. The ligamentous structures are critical in stabilizing the radius as it rotates about the ulna (Fig. 11-23).
TREATMENT OPTIONS FOR FRACTURES OF THE DISTAL RADIUS AND ULNA
Nonoperative Treatment of Fractures of the Distal Radius and Ulna
The goal of pediatric distal radius fracture care is to achieve bony union within acceptable radiographic parameters to optimize long-term function and avoid late complications. Management is influenced tremendously by the remodeling potential of the distal radius in growing children (Fig. 11-24). In general, remodeling potential is dependent upon the amount of skeletal growth remaining, proximity of the injury to the physis, and relationship of the deformity to plane of adjacent joint motion. Fractures in very young children, close to the distal radial physis, with predominantly sagittal plane angulation have the greatest remodeling capacity. Acceptable sagittal plane angulation of acute distal radial metaphyseal fractures has been reported to be from 10 to 35 degrees in patients under 5 years of age.63,108,114,147,161,169,209 Similarly, in patients under 10 years of age, the degree of acceptable angulation has ranged from 10 to 25 degrees.63,108,114,147,161,169,209 For children over 10 years of age, acceptable alignment has ranged from 5 to 20 degrees depending on the skeletal maturity of the patient (Table 11-4).
TABLE 11-4 Angular Corrections in Degrees
Criteria for what constitutes acceptable frontal plane deformity have been more uniform. The fracture tends to displace radially with an apex ulnar angulation. This deformity also has remodeling potential,152,221 but less so than sagittal plane deformity. Most authorities agree that 10 degrees or less of acute malalignment in the frontal plane should be accepted. Greater magnitudes of coronal plane malalignment may not remodel and may result in limitations of forearm rotation (Table 11-4).42,44,54,62,208
In general, 20 to 30 degrees of sagittal plane angulation, 10 to 15 degrees of radioulnar deviation, and complete bayonet apposition with reliably remodel in younger children with growth remaining.50,70,97,221
For the reasons cited above, the vast majority of pediatric distal radius fractures may be successfully treated with nonoperative means. General indications for nonoperative treatment include torus fractures, displaced physeal or metaphyseal fractures within acceptable parameters of expected skeletal remodeling, displaced fractures with unacceptable alignment amenable to closed reduction and immobilization, and late presenting displaced physeal injuries.
Contraindications to nonoperative care include open fractures, fractures with excessive soft tissue injury or neurovascular compromise precluding circumferential cast immobilization, irreducible fractures in unacceptable alignment, unstable fractures failing initial nonoperative care, and fractures with displacement that will not remodel (Table 11-5).
TABLE 11-5 Distal Radius Fractures
Techniques: Splint Immobilization of Torus Fractures
By definition, torus fractures are compression fractures of the distal radial metaphysis and are therefore inherently stable (Fig. 11-25). There is typically minimal cortical disruption or displacement. As a result, treatment should consist of protected immobilization to prevent further injury and relieve pain. Multiple studies have compared the effectiveness and cost of casting, splinting, and simple soft bandage application in the treatment of torus fractures. As expected, there is little difference in outcome of the various immobilization techniques.2,21,102,145,161,171,180,205
Davidson et al.43 randomized 201 children with torus fractures to plaster cast or removable wrist splint immobilization for 3 weeks. All patients went on to successful healing without complications or need for follow-up clinical visits or radiographs. Similarly, Plint et al.159 reported the results of a prospective randomized clinical trial in which 87 children were treated with either short-arm casts or removable splints for 3 weeks. Not only were there no differences in healing or pain, but also early wrist function was considerably better in the splinted patients. West et al.207 even challenged the need for splinting in their clinical study randomizing 39 patients to either plaster casts or soft bandages. Again, fracture healing was universal and uneventful, and patients treated with soft bandages had better early wrist motion.
Given the reliable healing seen with torus fracture healing, Symons et al.184 performed a randomized trial of 87 patients treated with plaster splints to either hospital follow-up or home removal. No difference was seen in clinical results, and patient/families preferred home splint removal. A similar study by Khan et al.115 confirmed these findings. No differences in outcomes were seen in 117 patients treated with either rigid cast removal in fracture clinic versus soft cast removal at home, and families preferred home removal of their immobilization.
A recent meta-analysis of torus and minimally displaced fractures treated by removable splints instead of circumferential casts was found to have improved secondary outcomes for the patient and family and with equal position at healing.11 Therefore, simple splinting is sufficient, and once the patient is comfortable, range-of-motion exercises and nontraumatic activities may begin. Fracture healing usually occurs in 3 to 4 weeks.2,10 Simple torus fractures heal without long-term sequelae or complications.
Techniques: Cast Immobilization of Nondisplaced or Minimally Displaced Distal Radial Metaphyseal and Physeal Fractures
Nondisplaced fractures are treated with cast immobilization until appropriate bony healing and pain resolution have been achieved.47,52,173 Although these fractures are radiographically well aligned at the time of presentation, fracture stability is difficult to assess and a risk of late displacement exists (Fig. 11-26). Serial radiographs are obtained in the first 2 to 3 weeks to confirm maintenance of acceptable radiographic alignment. In general, most fractures will heal within 4 to 6 weeks.
Simple immobilization without reduction may also be considered in minimally displaced fractures within acceptable alignment, based upon patient age and remodeling potential. Hove and Brudvik98 evaluated a cohort of 88 patients treated nonoperatively for distal radius fractures. Though eight patients had early loss of reduction with greater than 15 to 20 degrees angulation, all demonstrated complete remodeling and restoration of normal function. Al-Ansari et al. similarly evaluated 124 patients with “minimally angulated” distal radius fractures. Even patients who healed with 30 to 35 degrees angulation went on to complete fracture remodeling and normal function.5 Finally, in a prior randomized clinical trial, 96 patients between 5 and 12 years of age with distal radius fractures with less than 15 degrees of sagittal plane angulation were treated with either cast or splint immobilization.21 No difference were seen in fracture alignment at 6 weeks in the two treatment groups, and functional outcomes did not differ, as measured by the Activity Scale for Kids. Though the risk of late displacement and issues of compliance and comfort exist, this investigation supports the concept that splint immobilization may be considered in younger patients with minimal displacement.
Furthermore, cast immobilization alone without fracture manipulation may be effective in young patients with complete dorsal displacement and bayonet apposition with acceptable sagittal and coronal plane alignments. Recently, Crawford et al. prospectively evaluated 51 children under the age of 10 years treated with cast immobilization for shortened and bayonetted fractures of the distal radial metaphysis.38,50 All patients went on to complete radiographic remodeling and full return of wrist motion.
Techniques: Reduction and Immobilization of Incomplete Fractures of the Distal Radius and Ulna
Treatment of incomplete distal radial and ulnar fractures is similarly dependent upon patient age and remodeling potential, magnitude, and direction of fracture displacement and angulation, and the biases of the care provider and patient/family regarding fracture remodeling and deformity. In cases of incomplete or greenstick distal radius fractures—with or without ulnar involvement—with unacceptable deformity, closed reduction and cast immobilization are recommended.
The method of reduction for greenstick fractures depends on the pattern of displacement. With apex volar angulated fractures of the radius, the rotatory deformity is supination. Pronating the radius and applying a dorsal-to-volar reduction force is utilized to restore bony alignment. Conversely, fractures with apex dorsal angulation result from pronation mechanisms of injury. Supinating the distal forearm and applying a volar-to-dorsal force should reduce the incomplete fracture of the radius.135 Though these fractures are incomplete and patients often present with minimal pain, adequate analgesia will facilitate bony reduction and quality of cast application. Typically this is done with the assistance of conscious sedation.64,79,114
Following reduction, portable fluoroscopy may be used to evaluate fracture alignment. Once acceptable alignment is achieved, a long-arm cast is applied with appropriate rotation and three-point molds, based upon the initial pattern of injury. Long-arm casting is typically used for the first 4 weeks, and bony healing is achieved in 6 weeks in the majority of patients.
The high potential for remodeling of a distal radial metaphyseal malunion has led some clinicians to recommend immobilization alone.50 As in the case of torus fractures,195 a recent study suggests that soft bandages can be applied to treat incomplete green stick forearm fractures;120 however, as the greenstick fracture is substantially more unstable than the torus fracture166 the authors do not advocate soft bandage treatment of greenstick fractures.
Techniques: Closed Reduction and Cast Immobilization of Displaced Distal Radial Metaphyseal Fractures
Closed reduction and cast immobilization remains the standard of care for children with displaced distal radial metaphyseal fractures presenting with unacceptable alignment. Again, fracture reduction maneuvers are dependent upon injury mechanism and fracture pattern. In patients with typical dorsal displacement of the distal epiphyseal fracture fragment with apex volar angulation, closed reduction is performed with appropriate analgesia, typically conscious sedation or general anesthesia. Finger traps applied to the ipsilateral digits may facilitate limb positioning and stabilization during fracture reduction but application of weights may hinder reduction by increasing dorsal periosteal tension. Recently, the lower extremity-aided fracture reduction maneuver (LEAFR) has been proposed as a simple, effective, reproducible, and mechanically advantageous technique of effectuating closed reductions in children with bayoneted distal radius fractures.59 Given the stout, intact dorsal periosteum in these injuries, pure longitudinal traction is often insufficient to restore bony alignment, particularly in cases of bayonet apposition. Fracture reduction is performed first by hyperextension and exaggeration of the deformity, which relaxes the dorsal periosteal sleeve (Fig. 11-27). Longitudinal traction is then applied to restore adequate length. Finally, the distal fracture fragment is flexed to correct the translational and angular displacement, with rotational correction imparted as well. If available, fluoroscopy may be utilized to confirm adequacy of reduction, and a well-molded cast is applied.
The optimal type of cast immobilization remains controversial. Both long- and short-arm casts have been proposed following distal radial fracture reduction.31,88,93,205 Long-arm casts have the advantage of restricting forearm rotation and theoretically reducing the deforming forces imparted to the distal radius. However, above elbow immobilization is more inconvenient and has been associated with greater need for assistance with activities of daily living, as well as more days of school missed.205 Prior randomized controlled trials have demonstrated that short-arm casts are as effective at maintaining reduction as long-arm casts, provided that acceptable alignment is achieved and an appropriate cast mold is applied.20,205 A recent meta-analysis pooling the results of over 300 study subjects have further supported these findings.93
Perhaps more important than the length of the cast applied is the cast mold applied at the level of the fracture (Fig. 11-28). Appropriate use of three-point molds will assist in maintenance of alignment in bending injuries. Similarly, application of interosseous mold will help to maintain interosseous space between the radius and ulna as well as coronal plane alignment. A host of radiographic indices have been proposed to quantify and characterize the quality of the cast mold, including the cast index, three-point index, gap index, padding index, Canterbury index, and second metacarpal/distal radius angle (Fig. 11-29).10,57,90,162 Although the cast index is easily calculated and perhaps most widely utilized, some authorities tout the three-point index as the preferred index for this assessment and prediction of redisplacement.48
Complete fractures of the distal radius have a higher rate of loss of reduction after closed treatment than do incomplete fractures (Fig. 11-30).246 Indeed, prior investigations have demonstrated that 20% to 30% of patients will have radiographic loss of reduction following closed reduction and casting of displaced distal radius fractures. Risk factors for loss of reduction include greater initial fracture displacement and/or comminution, suboptimal reduction, suboptimal cast mold, associated distal ulnar fractures.7,10,48,57,90,139,162
Given the risk of radiographic loss of reduction, serial radiographs are recommended in the early postinjury period. Weekly radiographs are obtained in the first 2 to 3 weeks following reduction to confirm adequacy of alignment. Failure to identify and correct malalignment in the early postinjury period may lead to malunion and subsequent clinical loss of motion and upper limb function.
Malalignment of fractures during the development of soft tissue callus before bridging ossification (injury to 2 to 3 weeks after reduction) often can be realigned using cast wedging (Fig. 11-31).14,17,36,85,101,190,206 Recently, this technique has been utilized less frequently given the advances in surgical management of fractures. Authors have advocated opening wedges, closing wedges, as well as a combination of each of these approaches. Most commonly we use open wedge techniques as closing wedges have the potential for pinching of the skin and causing accumulation of cast padding at the wedge site which may cause skin breakdown.85,101 In addition, closing wedges also may shorten and reduce the volume of the cast thus decreasing fracture stability. There have been multiple techniques proposed for predicting the size of a wedge. Bebbington et al.14 suggested a technique that involves tracing the angle of displacement onto the cast itself thus representing the fracture fragments. Wedges are then inserted until the malalignment is reduced as the traced line becomes straight. Wells et al. recently described a technique in which the wedge position and opening angle are determined from the radiographic displacement and center of rotational alignment. Utilizing these methods on saw bones, they were able to reduce malalignment within 5 degrees with 90% success.206 Regardless of the method, if utilized appropriately, cast wedging reduces the risk of additional anesthesia and potential surgery.
Techniques: Displaced Distal Radial Physeal Fractures
Most displaced Salter–Harris I and II fractures are treated with closed reduction and cast stabilization. Closed manipulation of the displaced fracture is similarly performed with appropriate conscious sedation, analgesia, or, rarely, anesthesia to achieve pain relief and an atraumatic reduction.64,79,114 Most of these fractures involve dorsal and proximal displacement of the epiphysis with an apex volar extension deformity. Manipulative reduction is by gentle distraction and flexion of the distal epiphysis, carpus, and hand over the proximal metaphysis (Fig. 11-32). The intact dorsal periosteum is used as a tension band to aid in reduction and stabilization of the fracture. Unlike similar fractures in adults, finger trap distraction with pulley weights is often counterproductive. However, finger traps can help stabilize the hand, wrist, and arm for manipulative reduction and casting by applying a few pounds of weight for balance. Otherwise, an assistant is helpful to support the extremity in the proper position for casting.
If portable fluoroscopy is available, immediate radiographic assessment of the reduction is obtained. Otherwise, a well-molded cast is applied and AP and lateral radiographs are obtained to assess the reduction. The cast should provide three-point molding over the distal radius to lessen the risk of fracture displacement and should follow the contour of the normal forearm. The distal dorsal mold should not impair venous outflow from the hand, which can occur if the mold is placed too distal and too deep so as to obstruct the dorsal veins. Advocates of short-arm casting indicate at least equivalent results with proper casting techniques and more comfort during immobilization due to free elbow mobility. Instructions for elevation and close monitoring of swelling and the neurovascular status of the extremity are critical.
The fracture also should be monitored closely with serial radiographs to be certain that there is no loss of anatomic alignment (Fig. 11-33). Generally, these fractures are stable after closed reduction and cast immobilization. If there is loss of reduction after 7 days, the surgeon should be wary of repeat reduction, as forceful remanipulation may increase the risk of iatrogenic physeal arrest.27,125,174 Fortunately, remodeling of an extension deformity with growth is common if the patient has more than 2 years of growth remaining and the deformity is less than 20 degrees. Even marked deformity can remodel if there is sufficient growth remaining and the deformity is in the plane of motion of the wrist.
Techniques: Galeazzi Fractures
Nonoperative management remains the first-line treatment for pediatric Galeazzi fractures, distinguishing these injuries from their adult counterparts.56,169,198 Indeed, the adult Galeazzi fracture has been often called a “fracture of necessity,” given the near universal need for surgical reduction and internal fixation to restore anatomic radial alignment and DRUJ congruity. In pediatric patients, however, the distal radial fracture often is a greenstick type that is stable after reduction; therefore, nonoperative treatment with closed reduction and cast immobilization is sufficient.109,169 Surgical treatment may be considered for adolescents with complete fractures and displacement, as their injury pattern, skeletal maturity, and remodeling potential is more similar to the adult Galeazzi.
Incomplete fractures of the distal radius with either a true dislocation of the DRUJ or an ulnar physeal fracture are treated with closed reduction and long-arm cast immobilization. This can be done in the emergency room with conscious sedation or in the operating room with general anesthesia. Portable fluoroscopy is useful in these situations. If the radius fracture has apex volar angulation and dorsal displacement of the radius—and associated volar dislocation of the ulnar head in relationship to the radius, pronation and volar-to-dorsal force on the radial fracture is used for reduction. Conversely, if the radius fracture is apex dorsal with volar displacement and dorsal dislocation of the distal ulna, supination and dorsal-to-volar force is utilized during reduction. The reduction and stability of the fracture and DRUJ dislocation may then be checked on dynamic fluoroscopy; if both are anatomically reduced and stable, a long-arm cast with the forearm in the appropriate rotatory position (i.e., pronation or supination) is applied. Six weeks of long-arm casting is recommended to allow for sufficient bony and soft tissue healing.
In patients with Galeazzi equivalent injuries characterized by complete distal radius fractures associated with ulnar physeal fractures, both bones should be reduced. Usually, this can be accomplished with the same methods of reduction as when the radial fracture is incomplete. If there is sufficient growth remaining and the distal ulnar physis remains open, remodeling of a nonanatomic distal ulnar physeal reduction may occur. As long as the DRUJ is reduced, malalignment of less than 10 degrees can remodel in a young child. DRUJ congruity and stability, however, are dependent upon distal ulnar alignment, and great care should be taken in assessment of the DRUJ when accepting a nonanatomic distal ulnar reduction. Furthermore, the risk of ulnar growth arrest after a Galeazzi equivalent has been reported to be as high as 55%.81 If the fracture is severely malaligned, the DRUJ cannot be reduced, or the patient is older and remodeling is unlikely, open reduction and smooth pin fixation are indicated.209
Techniques: Distal Radial Physeal Stress Fractures
Treatment of distal physeal stress injuries first and foremost involves rest. This activity restriction may be challenging in the pediatric athlete, depending on the level of the sports participation and the desires of the child, parents, and other stakeholders to continue athletic participation. Education regarding the long-term consequences of a growth arrest is important in these emotionally charged situations. Short-arm cast immobilization for several weeks may be the only way to restrict stress to the distal radial physis in some patients. Splint protection is appropriate in cooperative patients. Protection should continue until there is resolution of tenderness and pain with activity. The young athlete can maintain cardiovascular fitness, strength, and flexibility while protecting the injured wrist. Once the acute physeal injury has healed, return to weight-bearing and open-chain activities should be gradual. The process of return to sports should be gradual, often 3 to 6 months, and adjustment of techniques and training methods is necessary to prevent recurrence. The major concern is development of a radial growth arrest in a skeletally immature patient, and consideration should be given to serial clinical and radiographic follow-up in high-risk patients to confirm maintenance of growth.
Techniques: Distal Ulna Physeal Fractures
Treatment options are similar to those for radial physeal fractures: immobilization alone, closed reduction and cast immobilization, closed reduction and percutaneous pinning, and open reduction. Often, these fractures are minimally displaced or nondisplaced. Immobilization until fracture healing at 3 to 6 weeks is standard treatment. Closed reduction is indicated for displaced fractures with more than 50% translation or 20 degrees of angulation. Most ulnar physeal fractures reduce to a near anatomic alignment with reduction of the concomitant radius fracture due to the attachments of the DRUJ ligaments and TFCC. Failure to obtain a reduction of the ulnar fracture may indicate that there is soft tissue interposed in the fracture site, necessitating open reduction and fixation.
Most of the published literature provide information on the short-term clinical and radiographic results of treatment for pediatric distal radius fractures indicates a positive outcome. With adherence to the principles and techniques described above, radiographic realignment, successful bony healing, and avoidance of complications are achieved in the majority of cases. Given the high healing capacity and remodeling potential of these injuries, there is less concern regarding long-term outcomes of nonoperative treatment compared with adult patients. In general, concerns regarding long-term outcomes have focused on patients who sustain distal radial physeal fractures and thus are at risk for subsequent growth disturbance and skeletal imbalance of the distal forearm.
The risk of growth disturbance following distal radial physeal fractures is approximately 4%. Cannata et al.27 previously reported the long-term outcomes of 163 distal radial physeal fractures in 157 patients. Displaced fractures were treated with closed reduction and cast immobilization for 6 weeks. Mean follow-up was 25.5 years. Posttraumatic growth disturbance resulting in 1cm or greater of length discrepancy was seen in 4.4% of distal radial and 50% of distal ulnar physeal fractures. In a similar prospective analysis of 290 children with distal radial physeal fractures, Bae and Waters12 noted that 4% of patients went on to demonstrate clinical or radiographic distal radial growth disturbance. Consideration should be given for follow-up radiographic evaluation following distal radial physeal fractures to assess for possible physeal arrest. In symptomatic patients with posttraumatic growth disturbance and growth remaining, surgical interventions including distal ulnar epiphysiodeses, corrective osteotomies of the radius, ulnar shortening osteotomies, and associated soft tissue reconstructions have been demonstrated to improve clinical function and radiographic alignment.201
Operative Treatment of Fractures of the Distal Radius and Ulna
Although surgical indications and techniques continue to evolve, in general surgical indications for pediatric distal radius and ulna fractures include open fractures, irreducible fractures, unstable fractures, floating elbow injuries, and fractures with soft tissue or neurovascular compromise precluding circumferential cast immobilization. Surgical reduction and fixation is also indicated in cases of joint incongruity associated with intra-articular Salter–Harris III, IV, or “triplane” fractures.
Distal radial fracture stability has been more clearly defined in adults204 than in children. At present, an unstable fracture in a child is often defined as one in which closed reduction cannot be maintained. Pediatric classification systems have yet to more precisely define fracture stability, but this issue is critical in determining proper treatment management. As noted above, distal radial metaphyseal fractures have been shown to have a high degree of recurrent displacement and, therefore, inherent instability7,10,48,57,90,138,162,204 For these reasons, pediatric distal radial metaphyseal fractures are not classified in the same manner as adults in regard to stability. Instead, unstable fractures have been predominately defined by the failure to maintain a successful closed reduction. Irreducible fractures usually are due to an entrapped periosteum or pronator quadratus.
Surgical treatment is similarly recommended in patients with neurovascular compromised and severely displaced injuries. Operative stabilization serves both to maintain adequate bony alignment and more importantly, minimize the risk of compartment syndrome due to excessive swelling and circumferential immobilization. Perhaps the best indication is a displaced radial physeal fracture with median neuropathy and significant volar soft tissue swelling (Fig. 11-34).202 These patients are at risk for development of an acute carpal tunnel syndrome or forearm compartment syndrome with closed reduction and well-molded cast immobilization.15,44,202 The torn periosteum volarly allows the fracture bleeding to dissect into the volar forearm compartments and carpal tunnel. If a tight cast is applied with a volar mold over that area, compartment pressures can increase dangerously. Percutaneous pin fixation allows the application of a loose dressing, splint, or cast without the risk of loss of fracture reduction.