Pertinent Anatomy

The pediatric skeleton is unique in multiple ways. The presence of the physis or growth plate provides longitudinal growth. The physis is divided into four distinct zones: germinal, proliferative, hypertrophic, and provisional calcification. The hypertrophic and provisional calcification zones are relatively weaker than the germinal and proliferative layers.^6,7 Classically, fracture lines tend to pass through the hypertrophic and provisional calcification zones. However, high-energy injuries may undulate through all four zones of the physis.^6–9

The presence of the secondary ossification center is another distinguishing feature that can complicate fracture detection. The distal radius epiphysis is absent at birth and appears at approximately 1 year of age. Specifically, the appearance is between 0.5 and 2.3 years in boys and between 0.4 and 1.7 years in girls.¹⁰ The configuration of the epiphysis also changes with age. Initially, the epiphysis is transverse in shape and becomes more triangular with time. The radial physis closes at approximately 16 years of age in girls and 17 years of age in boys.¹¹ The distal radius and ulnar physis contribute 75% to 80% of the forearm growth and 40% of the entire upper extremity.¹²

Indications

The principal surgical indications for pediatric distal radius fractures are irreducible fractures, displaced intra-articular fractures, and Galeazzi fracture-dislocations. Irreducible fractures require open reduction to extricate the offending structure from the fracture site. In children, the interposed structure is usually periosteum. Intra-articular fractures are relatively uncommon in children and often secondary to high intensity sports. The fracture pattern is usually a Salter-Harris III or IV fracture. Similar to adults, articular congruity must be restored to prevent traumatic arthritis and to decrease the chances of a physeal arrest. Galeazzi fractures are less common in children than adults. The treatment principles in adults and children are similar with reduction of the radius and the distal radioulnar dislocation. Unfortunately, the pediatric Galeazzi fracture-dislocation is often treated as an isolated radius fracture without appreciation of the distal radioulnar joint (DRUJ) component. Subsequently, the patient fails to regain forearm rotation and the distal radioulnar injury is recognized late.

Additional indications for surgery are open fractures and fractures associated with nerve injuries, such as carpal tunnel syndrome (Figs. 15-1 and 15-2). The treating physician must be aware that children and adolescents do not routinely complain of numbness. In addition, sensation is difficult to examine in the pediatric patient and two-point discrimination is unreliable until about 9 years of age. Therefore, the physician must have a high index of suspicion for nerve compression after treatment of markedly displaced fractures. The treatment principles for open fractures and fractures associated with nerve injuries are similar to those for adults and will not be specifically addressed in this chapter.

FIGURE 15-1 A 16-year-old boy with multiple hereditary exostosis sustained a displaced left distal radius fracture. Closed reduction and casting was performed. Anteroposterior (A) and lateral (B) radiographs after closed reduction.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-2 The patient developed acute carpal tunnel syndrome requiring emergent open reduction and internal fixation along with carpal tunnel release. Anteroposterior (A) and lateral (B) radiographs after open reduction and internal fixation.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

Surgical considerations are influenced by a variety of parameters unique to children. First, the timing of surgery is different in children compared with adults. Children heal more quickly than adults and form abundant callus faster. Therefore, surgery performed within the first week after injury is preferable. Second, the potential for remodeling is present in children. Fractures about the physis will remodel, especially in young children and particularly in the sagittal plane of motion. Consequently, considerable angulation is acceptable in the young child and less angulation in the adolescent approaching skeletal maturity. Third, growth plate fractures injure the physis and additional manipulation or surgery may further damage the growth potential. Repeat manipulations are particularly harmful to the physis and should be avoided. Children who present later than 1 week after injury or have partially lost reduction pose particular problems. In these cases, the surgeon must compare and contrast the risk/benefit ratio of surgical intervention on the growth plate with the remodeling capacity of the child.

Contraindications

Contraindications for surgery stem from the indications just listed. The main point that distinguishes children from adults is the remodeling capacity of the immature skeleton. Displaced fractures that would require surgery in adults are often acceptable in children, especially growth plate fractures and fractures that present late. The surgeon must avoid unnecessary surgery that could do additional harm, particularly in the very young child.

Surgical Technique

Intra-articular Fractures

Displaced Salter-Harris III and IV fractures require surgery to restore anatomical alignment of the joint surface.¹³ The goal of internal fixation is intraepiphyseal fixation with avoidance of the physis. If fixation must cross the physis, smooth pins are preferable to limit further physeal injury. Mini-fluoroscopy is invaluable to assess joint alignment and implant fixation. External fixation may be necessary to augment the fixation and to unload the joint surface until satisfactory healing has occurred.

The specific approach depends on the fracture configuration (Fig. 15-3). Computed tomography (CT) can further delineate the fracture pattern. In general, the approach is directed at the fracture fragment. A dorsal fragment requires a dorsal longitudinal incision along Lister’s tubercle. Sharp dissection is performed to the extensor retinaculum. Skin flaps are elevated from this level. The third compartment is opened, and the extensor pollicis longus is transposed in a radial direction. The posterior interosseous nerve is identified and resected to prevent postoperative neuroma formation. The second and fourth compartments are retracted, and a longitudinal capsulotomy is performed.

FIGURE 15-3 A 14-year-old boy with a history of Blount’s disease fell from a bicycle sustaining an intra-articular Salter-Harris III fracture. Anteroposterior (A), oblique (B), and lateral (C) radiographs.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

Any hemarthrosis within the joint is evacuated. The capsulotomy may require extension into a T-configuration to increase exposure. The distal radial surface is exposed, and a reverse retractor is placed on the volar lip. The joint surface is examined, and the fracture line is delineated. Hematoma is removed from the fracture site. The fracture is then reduced, and provisional fixation is obtained using K wires drilled from dorsal to palmar.

Fluoroscopic imaging is used to confirm joint reduction and wire position—preferably intraepiphyseal fixation with avoidance of the physis. Direct joint inspection avoids intra-articular wire placement. In sequential fashion, the pins are removed and replaced with compression screws across the fracture (Fig. 15-4). The placement of screws across the physis is avoided. At this point, the fixation is assessed and a determination made regarding the necessity of an external fixator to unload the joint surface until healing has occurred. In children, I have a low threshold to apply an external fixator because compliance is unlikely. The fixator is placed using standard open incisions. Distraction is applied until the scaphoid and lunate are elevated from the articular surface to eliminate compressive forces until union. Standard closure is performed with absorbable suture, and the external fixator is securely tightened. The tourniquet is deflated to ensure capillary refill. A long arm splint is applied. The external fixator is removed 5 to 6 weeks after surgery. Active and active-assisted range of motion is instituted. Formal therapy is usually not required.

FIGURE 15-4 Open reduction and internal fixation using intraepiphyseal screws. Adjuvant external fixation was applied to protect fixation until union. Anteroposterior (A) and lateral (B) radiographs after fixation.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

Arthroscopically assisted reduction has been described to directly visualize the articular surface.^14,15 However, this technique is relatively demanding and requires additional equipment. I prefer direct visualization of the joint surfaces.

Pediatric Galeazzi Fractures

The most common pattern of pediatric Galeazzi fracture is when there is dorsal displacement of the distal radius fracture and volar displacement of the distal ulna (Fig. 15-5). A less common type is when there is volar displacement of the distal radius and dorsal displacement of the distal ulna.¹⁶ Regardless of the pattern, recognition of the disrupted DRUJ is mandatory. A true lateral radiograph is necessary to assess the status of the DRUJ. The injury pattern can also involve the distal ulnar physis and then is called a Galeazzi-equivalent fracture.

FIGURE 15-5 A 15-year-old boy fell and sustained a Galeazzi fracture-dislocation. A, Anteroposterior view with shortening. B, Lateral radiograph demonstrates the volar position of the ulna relative to the radius.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

Unlike in adult Galeazzi fractures, closed reduction can be successful as long as the DRUJ congruity is reestablished. This tenet is especially true in children with incomplete fractures of the radius. The reduction maneuver involves realignment of the distal radius fragment and rotation of the forearm to restore DRUJ congruity. The direction of forearm rotation depends on the position of the distal ulna; pronation is used for volar displacement and supination is used for dorsal displacement. A long arm cast is required for 6 weeks. Post-reduction radiographs must demonstrate anatomical reduction or additional treatment is required. Questionable reduction requires a CT scan for verification. Adolescents with complete fractures of the distal radius are treated like adults with Galeazzi fractures and require internal fixation.

Open reduction and internal fixation is accomplished via a volar trans–flexor carpi ulnaris (FCR) approach. Stable internal fixation is required. The radial artery and FCR tendon are identified by palpation. The limb is exsanguinated, and the tourniquet is inflated. A longitudinal incision is made measuring directly over the FCR tendon beginning just proximal to the wrist crease. Sharp dissection is performed down the tendon sheath, which is incised in a longitudinal direction. The tendon is retracted in a radial direction, and the underlying subsheath is incised with the knife to reveal the volar compartment muscles and tendons. These structures are swept in an ulnar direction with a moist sponge directly over the pronator quadratus.

The pronator quadratus is elevated from the radius in an extraperiosteal manner leaving a 2-mm sleeve along the radial border. The radius and fracture site are clearly exposed (Fig. 15-6). Hematoma is removed from the fracture site. The fracture is reduced under direct visualization (Fig. 15-7). Fixation can be accomplished using a variety of plates. The fixation device selected should consider the close proximity of the growth plate. Fixed-angle devices provide rigid fixation distal to the fracture site and can avoid the physis. Mini-fluoroscopy is used to assess fracture reduction and internal fixation placement (Fig. 15-8).

FIGURE 15-6 Exposure of the fracture site reveals considerable displacement.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-7 Open reduction and internal fixation with T-plate.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-8 Radiographs after internal fixation with T-plate that avoids the physis. A, Anteroposterior view with anatomical reduction. B, Lateral view with distal radioulnar joint reduction.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

At this point, the status of the DRUJ is assessed. Usually, anatomical restoration of the radius results in DRUJ reduction. On rare occasion, the DRUJ is irreducible because of interposed tissues.^17–19 Periosteum or tendon (e.g., extensor carpi ulnaris or extensor digiti quinti) can be blocking reduction. Exploration of the DRUJ is necessary to remove the offending agent. A separate ulnar approach to the DRUJ is necessary.

Closure is performed with careful repair of the pronator quadratus followed by layered skin closure. The FCR tendon sheath is not repaired. The tourniquet is deflated to ensure capillary refill. A long arm splint is applied to maintain reduction of the DRUJ. The splint is changed to a long arm cast 2 weeks after surgery. The cast is removed 6 weeks after surgery, and wrist and forearm range of motion exercises are started.

Clinical Pearls

The standard hardware may not be appropriate in children considering their small size and proximity of the fracture to the growth plate. Smaller implants are necessary because standard fixation devices overwhelm the bone and create an unnecessary stress riser. In addition, devices that are T-shaped are often necessary to obtain adequate distal fixation and to avoid fixation across the physis. Locking plates with variable-angle fixation offer several advantages, including distal fixation, avoidance of the physis, and biomechanical strength.

Results

The actual results of pediatric and adolescent distal radius fractures are difficult to decipher based on the literature. In general, most children do well with closed or open treatment as long as the treatment approach adheres to the standard guidelines previously discussed. However, a study that shows consistently good outcomes is often not worthy of formal publication. Instead, most reports discuss complications of distal radius fractures, such as growth arrest, missed fracture-dislocations, and instability.^20–24

Another confounding factor is that the standard measurements of outcome in adults after wrist fracture (e.g., Disabilities of the Arm, Shoulder, and Hand [DASH] and Mayo wrist scores) are not applicable to the growing child. Children are unable to comply with the measure and are very adaptable to mild impairment. This reality complicates the construction of valid outcome measurements in children. Extensive pediatric outcome research is underway that may improve our ability to critically assess the outcomes after injuries in children, including distal radius fractures.

Complications

Growth plate closure occurs in 4% to 5% of all Salter-Harris distal radius fractures.^20,21 All growth plate fractures require a radiograph 3 to 6 months after healing to ensure continued growth. Failure to recognize a growth plate arrest can lead quickly to deformity (Figs. 15-9 and 15-10). The deformity varies according to the location and extent of the physeal bar. Peripheral bars lead to angular deformity as unequal growth occurs. In contrast, small central bars cause tenting of the articular surface and larger bars prevent any longitudinal growth, which results in shortening of the radius relative to the ulna. Advanced imaging studies better delineate the size and location of the physeal bar (Fig. 15-11). Management depends on the location of the bar, size of the bar, and the amount of remaining growth. Radioulnar discrepancy of less than 1 cm is well tolerated at long-term follow-up.²¹ Options include resection of the bar, formal epiphysiodesis, corrective osteotomy, and distraction osteogenesis. In addition, the ulna may be addressed by epiphysiodesis and/or shortening (Fig. 15-12).

FIGURE 15-9 A 14-year-old girl presented 6 months after a distal radius Salter-Harris II fracture with radius deformity and prominent ulna. Lateral radiograph reveals loss of volar tilt.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-10 Anteroposterior radiograph shows shortening of the radius with markedly positive ulnar variance.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-11 A 13-year-old girl with a radius fracture presented with growth arrest and ulnar abutment. A, Coronal MR image shows central bar in midportion of growth plate. B, Sagittal MR image shows position of the physeal bar.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-12 Patient shown in Figure 15-17 after a corrective osteotomy, bone grafting, and ulnar epiphysiodesis. A, Anteroposterior radiograph shows restoration of radial length. B, Lateral radiograph demonstrates reestablishment of volar tilt.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

Malunion after distal radius fractures is common, but remodeling with growth results in gradual correction. Angulation less than 20 degrees will remodel over 2 years; greater angulation requires additional growth. If the patient is close to skeletal maturity, little remodeling can be expected. Corrective osteotomy with bone grafting is indicated in patients with pain or limited motion. The goal is to restore alignment to alleviate pain, enhance motion, correct midcarpal instability, or prevent degenerative arthritis.²² The surgery should correct both the sagittal and coronal alignment (Fig. 15-13). A distal radius corrective osteotomy can be addressed from a dorsal or volar approach. Similar to adults, the volar approach and volar locking systems have gained popularity to avoid prominent hardware. A trans-FCR exposure is performed. The malunion site is identified. The distal portion of a fixed-angle plate is contoured and applied parallel to the physis and articular surface (Fig. 15-14). Mini-fluoroscopy is used to avoid the physis. The plate protrudes from the proximal radius but acts as a guide to correction. The radius is cut parallel to the physis and articular surface at the level of malunion. The osteotomy is opened using a laminar spreader, and the plate is used as a guide to correction. The proximal plate is affixed to the radius using a bone reduction clamp. Correction is assessed via mini-fluoroscopy, and adjustments made accordingly. The plate is then firmly secured to the radius using bicortical screw fixation (Fig. 15-15). Cancellous bone graft is placed within the osteotomy site. The graft can be harvested from the ulna or iliac crest depending on the size of the defect. I do not use bone graft substitutes because ample autologous bone is available. Radiographs are taken to verify correction of the coronal and sagittal alignment (Fig. 15-16).

FIGURE 15-13 A 16-year-old boy with symptomatic malunion of the distal radius. A, Anteroposterior radiograph reveals loss of radial inclination. B, Lateral radiograph shows mild loss of radial tilt but considerable carpal malalignment.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-14 Volar approach with fixation of volar plate parallel to the physis. Plate protruding from the radius demonstrated a degree of malunion.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-15 Plate was reduced to the proximal radius to correct the volar tilt and maintain radial inclination.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

FIGURE 15-16 Intraoperative radiographs after corrective osteotomy and before bone graft. A, Anteroposterior radiograph reveals a locking plate proximal to the physis and normal radial inclination. B, Lateral radiograph shows good position of plate and screws and restoration of radial tilt.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

Intra-articular malunion can occur after a Salter-Harris III or IV fracture. Fortunately, this malunion is uncommon because treatment is very difficult. The surgeon must weigh the risk/benefit ratio between intra-articular osteotomy and acceptance of the malunion. An advanced imaging study, preferably a CT scan, can delineate the magnitude of incongruity and is essential in the decision-making process.

A missed Galeazzi fracture-dislocation is a formidable problem. The ulna is subluxated and forearm rotation is limited. Treatment depends on time from the injury and the status of the DRUJ. Early recognition can be treated with corrective osteotomy of the radius and reduction of the DRUJ. Later recognition requires assessment of the articular surfaces of the distal ulna and sigmoid notch. Articular degeneration is a contraindication for reduction. In these cases, a salvage procedure, such as a Darrach or Sauvé-Kapandji, is required (Fig. 15-17). Fortunately, this injury occurs in children close to skeletal maturity and progressive ulnar-negative variance is not a concern because ulnar-negative variance up to 1 cm is usually asymptomatic.²¹ However, in the young child the length of the ulna needs to be addressed by distraction osteogenesis.

FIGURE 15-17 A 16-year-old wrestler with a chronic volar Galeazzi fracture-dislocation and articular degeneration was treated with matched distal ulnar resection and tenodesis. Anteroposterior radiograph demonstrates matched resection with some bony regrowth.

(Courtesy of Shriners Hospital for Children, Philadelphia, PA.)

Persistent pain after distal radius fracture may be related to an associated chondral injury, triangular fibrocartilage (TFC) tear, or scapholunate ligament injury. These injuries are rare in children. Most TFC and scapholunate ligament tears are partial and can be treated by arthroscopic inspection and débridement. Arthroscopic treatment can result in long-term improvement.^23,24 In cases of peripheral TFC tears, open or arthroscopic repair is warranted.²⁴

Volar fixation with plate and screws can result in prominent hardware along the dorsum of the distal forearm and wrist area. The child presents with extensor tenosynovitis of the irritated tendons. This finding is a forewarning of future problems, including tendon rupture. Treatment requires plate and screw removal, which can be difficult with titanium implants. Another option is dorsal exposure and burring the prominent screw head(s).