Elbow fractures are common in pediatric patients. Most injuries to the pediatric elbow are stable and require simple immobilization; however, more severe fractures can occur, often requiring operative stabilization and/or close monitoring. This article highlights the common fractures and dislocations about the pediatric elbow and discusses the history, evaluation, and treatment options for specific injuries.
Key points
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Elbow fractures are common in pediatric patients.
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Most injuries to the pediatric elbow are stable and require simple immobilization; however, more severe fractures can occur, often requiring operative stabilization and/or close monitoring.
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Careful clinical and radiographic evaluation can lead to an accurate diagnosis and prompt, appropriate treatment.
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Although many injuries about the elbow present pitfalls during diagnosis and treatment, most children recover excellent function and are able to return to premorbid activities with no limitations.
Introduction
Young children are at a significant risk for traumatic injuries that can lead to morbidity and mortality. Approximately 70% of fractures involve the upper extremity, with 8% to 10% involving the distal humerus or proximal radius and ulna. In 2005 alone, trauma to the upper extremity in children less than 19 years of age resulted in approximately $8 billion in direct health care costs and loss of estimated future income. The shoulder and elbow are the 2 joints responsible for positioning the hand in space for functional use. These actions allow infants and children to explore and interact with the world around them but place the upper extremity at risk for injury. The incidence of various fractures about the elbow peaks at different ages for children and depends highly on the specific activities performed as well as the maturity of the elbow.
The distal humerus physis develops as 4 distinct ossification centers, whereas the proximal radius and ulna each contribute 1 ossification center. The sequence of ossification is fairly predictable: the capitellum appears first between 1 and 2 years of age, followed by the radial head at 2 to 4 years of age, then the medial epicondyle at 4 to 6 years of age, the trochlea at 9 to 10 years of age, the olecranon at 9 to 11 years of age, and lateral epicondyle at 9.5 to 11.5 years of age. The appearance of the radial head is occasionally preceded by the medial epicondyle in girls, whose ossification centers typically appear 1 to 2 years earlier than boys. The trochlea, lateral epicondyle, and capitellum ossification centers fuse into the distal humeral epiphysis at around 11 years of age in girls and 13 to 14 years of age in boys. The radial head and olecranon ossification centers close at 12 to 13 years of age in girls and 14 to 15 years of age in boys. The medial epicondyle is the last to fuse to the distal humerus at 13 to 14 years of age in girls and 15 years of age in boys.
Introduction
Young children are at a significant risk for traumatic injuries that can lead to morbidity and mortality. Approximately 70% of fractures involve the upper extremity, with 8% to 10% involving the distal humerus or proximal radius and ulna. In 2005 alone, trauma to the upper extremity in children less than 19 years of age resulted in approximately $8 billion in direct health care costs and loss of estimated future income. The shoulder and elbow are the 2 joints responsible for positioning the hand in space for functional use. These actions allow infants and children to explore and interact with the world around them but place the upper extremity at risk for injury. The incidence of various fractures about the elbow peaks at different ages for children and depends highly on the specific activities performed as well as the maturity of the elbow.
The distal humerus physis develops as 4 distinct ossification centers, whereas the proximal radius and ulna each contribute 1 ossification center. The sequence of ossification is fairly predictable: the capitellum appears first between 1 and 2 years of age, followed by the radial head at 2 to 4 years of age, then the medial epicondyle at 4 to 6 years of age, the trochlea at 9 to 10 years of age, the olecranon at 9 to 11 years of age, and lateral epicondyle at 9.5 to 11.5 years of age. The appearance of the radial head is occasionally preceded by the medial epicondyle in girls, whose ossification centers typically appear 1 to 2 years earlier than boys. The trochlea, lateral epicondyle, and capitellum ossification centers fuse into the distal humeral epiphysis at around 11 years of age in girls and 13 to 14 years of age in boys. The radial head and olecranon ossification centers close at 12 to 13 years of age in girls and 14 to 15 years of age in boys. The medial epicondyle is the last to fuse to the distal humerus at 13 to 14 years of age in girls and 15 years of age in boys.
Supracondylar humerus fractures
Supracondylar humerus fractures are the most common pediatric elbow fracture, accounting for 3.3% of all pediatric fractures and 60% of pediatric elbow fractures. Biomechanically, the supracondylar region of the humerus is prone to injury because of the thin sheet of bone that sits between the medial and lateral columns. During a fall, children will attempt to brace themselves with their hand and wrist, which can transmit the force of the fall through an extended elbow joint to the supracondylar area. Tension on the anterior joint capsule, via elbow hyperextension, acts to further displace the fracture. Extension-type injuries resulting from a fall onto an outstretched hand (FOOSH) make up 97% of supracondylar fractures, whereas flexion-type injuries from a direct blow to the posterior olecranon compose the rest. Transphyseal injures have been described in infants and should be considered in patients with elbow swelling and pain before the development of ossification centers, especially in the setting of suspected or confirmed nonaccidental trauma. This injury is difficult to diagnose on plain radiographs, although it can be apparent as a misalignment of the humerus and ulna; ultrasound is a useful adjunct modality to confirm a suspected diagnosis. Because of this misalignment, transphyseal injuries can be misinterpreted as an elbow dislocation. However, the latter is exceedingly rare in infants and toddlers. The treatment of transphyseal injuries is the same as that in displaced supracondylar fractures. Closed reduction and percutaneous pinning are the mainstay of treatment, and an elbow arthrogram can assist with identifying appropriate landmarks during pinning to ensure that anatomic alignment is obtained.
The peak age for supracondylar fractures is between 5 and 7 years. The child presents with elbow pain, edema, and variable ecchymosis, often with significant deformity in severe injuries. Open fractures are noted in up to 3% of patients; concomitant injuries, typically involving the forearm or wrist, are seen in 11% of patients. Occult fractures are common in the developing elbow, typically presenting as painful, swollen elbows without definitive radiographic evidence of fracture. An anterior and/or posterior fat pad sign ( Fig. 1 A) is often the only indication of occult injury. A careful physical examination including palpation of the radial neck, olecranon, medial and lateral epicondyles, and supracondylar region will often reveal the location of an occult fracture, which is often only manifested radiographically as a healing fracture on routine follow-up radiographs. A careful neurologic and vascular examination must be performed in the emergency department and documented, such that it can be compared with a postreduction or postoperative examination in displaced fractures. Any evidence of vascular compromise or insufficiency to the hand, especially in patients with a cool, white, pulseless extremity, is considered an indication for emergent reduction and surgical fixation. Nerve injuries are present in 11.3% of supracondylar fractures, most commonly in the anterior interosseous nerve, median nerve, and radial nerve for extension-type injuries and the ulnar nerve in flexion-type injuries.
Standard anteroposterior (AP) and lateral radiographs are obtained to evaluate the injured elbow. Once a supracondylar humerus fracture is identified, AP and lateral forearm and posteroanterior and lateral wrist radiographs are mandatory for the evaluation of concomitant injuries to the forearm or wrist. The diagnosis of an additional forearm or wrist fracture, a pediatric floating elbow, imparts a substantially increased risk of compartment syndrome and indicates surgical fixation of unstable radius and ulna fractures, which could otherwise be managed nonoperatively with closed reduction and casting. Preoperative grading of supracondylar humerus fractures is based on the lateral view ( Table 1 ). A line drawn along the anterior cortex of the humerus shaft (anterior humeral line) should intersect or touch the capitellum. On the AP view, a postreduction determination of the angle between the long axis of the humerus shaft and the proximal capitellum ossification center, known as the Baumann angle, is typically performed. This angle, also known as the shaft-capitellum angle, normally lies between 64° and 81°; an increasing angle correlates with increasing clinical cubitus varus. It should be noted that there is confusion in the literature as to which angle Baumann was referring ; the Baumann angle has been frequently described, incorrectly, as the angle between a line perpendicular to the humeral shaft line and the superior border of the capitellum (the complement of the true Baumann angle).
| Type a | Description |
|---|---|
| I | Nondisplaced fracture |
| IIA | Displaced fracture with intact posterior cortical hinge |
| IIB | Displaced fracture with malrotation or lateral displacement without loss of cortical contact |
| III | Completely displaced fracture |
| IV b | Completely displaced fracture with multidirectional instability |
a Data from Wilkins KE. Fractures and dislocations of the elbow region. In: Rockwood CA, Wilkins KE, King RE, editors. Fractures in children, vol. 3. Philadelphia: JB Lippincott Co; 1984. p. 363–575.
b Data from Leitch KK, Kay RM, Femino JD, et al. Treatment of multidirectionally unstable supracondylar humeral fractures in children: a modified Gartland type-IV fracture. J Bone Joint Surg Am 2006;88:980–5.
Treatment in children is based on the Gartland classification, with type I fractures requiring only above-elbow cast treatment for 3 to 4 weeks until radiographic healing is noted. The treatment of type II injuries (see Fig. 1 B) remains controversial as some researchers advocate closed reduction and casting, whereas others advocate closed reduction and percutaneous pinning. Type II fractures, whereby the anterior humeral line touches the capitellum, can be treated in an above-elbow cast with weekly radiographs to ensure maintenance of alignment. Parikh noted that in type II injuries, closed reduction and casting in 90° to 100° of flexion resulted in adequate maintenance of alignment in 72% of patients; those that lost alignment during subsequent weekly follow-up were successfully converted to operative fixation when necessary. O’hara showed that closed reduction and plaster immobilization in type IIB (see Fig. 1 C) and III (see Fig. 1 D) fractures resulted in a 26% loss of reduction and surgical fixation. Type III injuries require expedient closed reduction and percutaneous pinning. In patients without neurovascular compromise, fixation can be delayed beyond 8 hours without an increased risk of patient morbidity and complications, allowing for patients presenting overnight to be treated the following morning, provided a qualified physician or assistant is available for close neurovascular monitoring.
Patients with type II and III injuries with neurovascular compromise or with concomitant unstable injury to the ipsilateral extremity should be taken to the operating room urgently for reduction and pinning. Indications for open reduction include open fractures and when interposed periosteum or neurovascular structures prevent anatomical alignment. This soft tissue interposition can often be detected during reduction maneuvers as a rubbery feeling instead of normal crepitus between fracture fragments. Any worsening of the vascular status of patients after reduction and pinning warrants an immediate surgical exploration by a qualified hand or vascular surgeon. Invasive vascular studies will delay diagnosis and add cost and possible morbidity while providing limited additional information that can be used in clinical decision making. In most cases of vascular compromise, the artery is simply tethered to the fracture by a supratrochlear branch of the brachial artery; however, arterial thrombus and intimal tear injuries can be seen and require exploration and repair or interpositional vein grafting.
During closed reduction, the fracture can be reduced via a milking procedure to remove interposed periosteum or brachialis muscle. The fracture is then distracted and flexed with anterior pressure on the olecranon. AP alignment can be verified via the Baumann angle, and lateral alignment is verified using the anterior humeral line. Typically, 2 divergent percutaneous 0.062-in Kirschner (K) wires are then placed through the lateral condyle into the medial metadiaphyseal distal humerus. One pin is fixated into the medial column, just above the fracture line, while the other is passed superior to the olecranon fossa to hold fixation into the lateral column. In patients with significant medial comminution or unstable reduction during fluoroscopic evaluation, a third pin can be placed either from a lateral or medial entry point. If a medial pin is used, 2 steps are performed to protect the ulnar nerve. First the elbow is brought into extension to decrease anterior ulnar nerve subluxation; secondly, a small incision is made to dissect down to the medial epicondyle and verify that the pin does not transect or impinge on the ulnar nerve during motion. The placement of a medial and lateral pin (cross pinning) is biomechanically equivalent in torsional stability to the placement of 2 divergent lateral pins in anatomically reduced fractures but provides superior fixation in malreduced fractures and those with medial comminution. In patients whereby reduction is blocked by soft tissue or edema, and the previously described milking procedure does not help, a posteriorly placed, percutaneous intrafocal K wire can be placed to assist with reduction. Care must be taken not to penetrate past the anterior cortex and risk damaging the neurovascular bundle. Open reduction is reserved for patients with arterial injury or when anatomic reduction cannot be obtained via closed methods. Compartment syndrome has been noted in 0.5% of all supracondylar fractures and in up to 6% of patients with questionable vascular status. In children, compartment syndrome is best diagnosed using the 3 As (anxiety, agitation, and analgesia). The first sign of impending compartment syndrome is an increasing need for narcotic analgesia, and sedating medications are contraindicated in the postoperative period as they can mask this need. This diagnosis is made clinically, and the measurement of compartment pressure often confuses the picture in that the natural diastolic pressure in children is often around 30 mm Hg. However, the measurement of compartment pressure can be useful in the operating room in order to compare preoperative and postoperative measurements, whereby a significant decrease in pressures can indicate that adequate release has been performed.
Nerve injuries associated with supracondylar humerus fractures typically resolve spontaneously over time. However, if no clinical or electromyographic recovery is noted after 5 months, exploration is warranted. Excellent recovery is typically noted with neurolysis, and sural nerve grafting is only required if a complete transection is identified. Cubitus varus or valgus can be seen in patients with inadequate initial reduction or inadequate fixation resulting in a loss of reduction. Symptomatic cubitus varus initially presents as a loss of carrying angle and painless, cosmetic deformity but can lead to tardy posterolateral elbow instability. The preferred treatment of cubitus varus is a closing wedge osteotomy, whereas more severe cubitus varus requires a step-cut osteotomy or dome osteotomy to prevent lateral prominence. Superficial pin tract infections are seen in approximately 1% of patients; deep infections, including osteomyelitis and septic arthritis, are noted in 0.2%.
Postoperative management includes the placement of a plaster splint or loose above-elbow cast in 50° to 60° of flexion. Patients with a neurovascular abnormality or at risk for compartment syndrome are admitted for frequent neurovascular checks. The cast is removed at 4 weeks, and pins are pulled if fracture healing is noted on postoperative radiographs. Gentle elbow range of motion is begun and continued until full motion is obtained.
Intraarticular humerus fractures
Fractures involving the articular surface of the distal humerus are the second most common elbow fractures, accounting for approximately 20% of all elbow fractures. Lateral condyle fractures are the most common at 16.9% of elbow fractures, followed by medial condyle fractures. Lateral condyle fractures occur when a varus force is directed across an extended elbow, leading to an avulsion force across the distal humerus physis via the lateral collateral ligament complex. The fracture line travels through the epiphysis and will sometimes dissipate before reaching the articular cartilage surface because of the inherent pliability of this structure. Medial condyle fractures occur via a valgus-directed force through a similar mechanism, although the trochlea does not ossify until 9 to 10 years of age, making this fracture difficult to identify on radiographs in young children.
Occasionally, the only sign of injury is a small avulsion fracture noted on plain radiographs, which frequently represents a large osteochondral avulsion fracture ( Fig. 2 ). Waters and colleagues termed these as TRASH lesions (The Radiographic Appearance Seemed Harmless) and recommended a low threshold for further imaging studies, including ultrasound, arthrography, or magnetic resonance imaging (MRI). In young children who require sedation for MRI, the author recommends an elbow arthrogram under anesthesia in the operating theater, with the plan for subsequent surgical fixation in the same setting as indicated by the radiographic findings.
The incidence of lateral condyle fractures peaks at 6 years of age, whereas the peak for medial condyle fractures is between 8 and 10 years of age. Patients complain of swelling and tenderness about the elbow following a fall from substantial height. AP and lateral radiographic images are often misleading with these injuries because of the oblique posterior fracture plane. The internal oblique view is usually the best view to detect a lateral condyle fracture and to evaluate displacement ; therefore, 4 views of the elbow, including AP, lateral, internal, and external oblique, are advised for suspected or confirmed condylar fractures. Computed tomography (CT) scans have been advocated by some as it allows for 3-dimensional (3D) visualization of the displacement seen in this complex fracture pattern; however, it does not allow for visualization of the articular surface and is not routinely recommended.
Lateral condylar fractures of the humerus were originally classified by Milch as entering the joint surface through the trochlea-capitellar groove (type I) or through the lateral wall of the trochlea (type II). Although this scheme postulated that type I fractures were more stable than type II, this was not borne out in later studies, which additionally showed a 52% rate of disagreement between radiographs and surgical findings. More recent classification schemes are based on the amount of displacement seen on the internal oblique radiograph and can be used to indicate surgical treatment ( Table 2 ). Fractures displaced less than 2 mm can be treated with close observation in an above-elbow cast until radiographic healing is noted ( Fig. 3 A). Weekly radiographs can be obtained in the cast to assess for changes in alignment; but the practitioner should have a low threshold for obtaining out-of-cast images, in cases when such assessment is difficult. Late fracture displacement, even 2 to 3 weeks after injury, can be seen (see Fig. 3 B), often in patients with initial examination findings of significant soft tissue swelling or pain out of proportion to the radiographic findings.
| Type | Displacement | Treatment |
|---|---|---|
| I | <2 mm | Cast with weekly follow-up |
| II | >2 mm with intact cartilage hinge seen on arthrogram | Closed reduction and percutaneous pinning |
| III | >2 mm with complete disruption of articular surface | Open reduction and pinning or internal fixation |
