Humerus and Elbow Injuries

Clinical features of humeral shaft fractures

Fractures of the humeral shaft commonly result from a direct blow to the arm, severe twisting, or a fall on an outstretched hand. Rarely, fractures may be caused by abrupt muscle contraction, such as occurs when a javelin or baseball is thrown. The shaft of the humerus most commonly fractures in the middle third in a transverse fashion. The patient reports localized pain, which is often severe in nature, and the arm is visibly swollen and cannot be used. When a fracture is complete, bony crepitus is felt in the shaft of the humerus with the slightest manipulation of the arm. The arm may be shortened or rotated, depending on the displacement of the fracture fragments. When the fracture is incomplete, there is bony tenderness and swelling without obvious deformity.

Diagnostic testing for humeral shaft fractures

Imaging studies should routinely include the shoulder and elbow joints. The humerus is a common site for benign tumors, unicameral cysts, and primary bone malignancies, as well as a common site for metastatic disease. Thinning of the cortex and abnormal osteoblastic or osteoclastic activity are evidence of a pathologic fracture ( Fig. 44.6 ). Pathologic lesions may require orthopedic surgical intervention, though once a fracture occurs, a multidisciplinary approach with oncology should occur to determine the best course of surgical intervention. While these fractures may be stabilized with treatment such as plates, pins, intramedullary nails, cement, and joint replacement, these underlying fractures do not heal well without concomitant treatment of the underlying pathologic condition.

Management of humeral shaft fractures

Isolated, closed fractures are treated with a high degree of success. Attempts at fracture reduction and external immobilization are generally unnecessary and may be detrimental to healing. Fractures that are nondisplaced or minimally displaced are immobilized by adding a coaptation, or “sugar-tong” splint, to the sling and swathe ( Fig. 44.7 ). The coaptation splint is often replaced by a functional brace after the first 10 to 14 days. If the fracture is grossly displaced or comminuted, the hanging cast technique is preferable. This technique is especially effective with spiral fractures ( Fig. 44.8 ). Care is taken not to make the cast too heavy because this would distract fracture fragments or too tight as this may compromise circulation. The hanging cast has the disadvantage of using gravity for traction and requires that the patient remain upright at all times, including during sleep, a situation that many patients find intolerable. Neurovascular examination should be repeated and documented before and after the application of any splint or cast because entrapment of the nerve between fragments can occur after these interventions. Open reduction and internal fixation ( Fig. 44.9 ) are necessary for open fractures, presence of multiple injuries that preclude mobilization, bilateral fractures, poor reduction, poor patient compliance, failure of closed treatment, and fractures through pathologic bone. Although the success rate with nonoperative intervention is about 80%, patients should be included in treatment decisions regarding nonoperative versus operative intervention because operative intervention may decrease recovery time resulting in earlier return to work.

For open fractures, the wound should be covered with normal saline soaked gauze. Splinting can be done for comfort during patient manipulation but should be limited. Cefazolin (2 g intravenously) is given, and consultation is obtained by orthopedic surgery for emergent operative washout. Additional antibiotics, such as an aminoglycoside or quinolone may be used as an alternate for gram negative coverage. For potential clostridial infection (e.g., contaminated farm injuries), clostridial coverage including clindamycin or metronidazole may also be indicated.

The most common complication, radial nerve injury, occurs in up to 15% of humerus fractures. Radial nerve injury causes wrist drop with loss of the ability to extend the fingers and thumb. This nerve injury is most often a benign neurapraxia that resolves spontaneously in approximately 80% to 90% of cases without operative intervention, although recovery may take 6 to 9 months. Of those with radial nerve palsy who fail conservative treatment, upwards of 90% of patients will recover. Patients should be advised of this possible complication prior to discharge, and follow-up with an orthopedic surgeon should be arranged from the ED. Exploration and internal fixation are indicated if the radial nerve palsy develops after manipulation, because this is highly suggestive of nerve entrapment. Radial nerve injuries associated with penetrating trauma or open fractures are likely to be caused by anatomical nerve disruption and generally warrant operative exploration. Median and ulnar nerve injuries are rare and usually secondary to penetrating trauma. Injuries to the brachial artery occur rarely and, if suspected, vascular surgery consultation is indicated, often with angiography or other vascular studies.

Disposition of humeral shaft fractures

All patients with humeral shaft fractures should be referred to an orthopedic surgeon for further evaluation within 48 hours after treatment in the ED to ensure that the alignment has been maintained, no neurological deficits have emerged, and pain is adequately controlled. Emergent referral to an orthopedist is recommended for patients with evidence of radial nerve injury, severely displaced or comminuted fractures, open fractures, or fractures associated with forearm fractures in the same injured extremity.

Supracondylar fractures

Distal humerus fractures that occur proximal to the epicondyles are called supracondylar fractures. This type of fracture is almost exclusively an injury of the immature skeleton, with a peak incidence in children 5 to 10 years old. This injury rarely occurs after age 15 and accounts for approximately one half of all elbow fractures and one third of pediatric limb fractures. In children, the tensile strength of the collateral ligaments and joint capsule of the elbow is greater than that of bone. In adults, the reverse is true, and a fall or accident that would result in a supracondylar fracture in children would likely result in a posterior elbow dislocation in an adult. Supracondylar fractures are classified as either extension or flexion fractures, depending on the mechanism of injury and the displacement of the distal fragment. Of these injuries, 98% are of the extension type.

Extension type supracondylar fractures

Clinical features of extension type supracondylar fractures

Extension supracondylar fractures occur as a consequence of a fall on the outstretched hand when the elbow is either fully extended or hyperextended (e.g., a fall off the playground “monkey bars”). The strong action of the triceps tends to pull and displace the distal fragment in a posterior and proximal direction. In children with extension-type supracondylar fractures, the arm is held at the side and has a characteristic S-shaped configuration, whereas with flexion-type supracondylar fractures, the forearm is supported with the opposite hand with the elbow flexed to 90 degrees. There may be anterior angulation of the sharp distal end of the proximal fragment into the antecubital fossa, which could injure the brachial artery and median nerve ( Fig. 44.10 ). In most cases, however, the brachialis muscle protects the anterior neurovascular structures from injury. Because this fracture primarily occurs in children, 25% of supracondylar fractures are of the greenstick variety, with the posterior cortex remaining intact. Subtle changes (e.g., the presence of a posterior fat pad or an abnormal anterior humeral line) may be the only radiographic clues to the presence of a fracture ( Fig. 44.11 ). Ten percent of children lose the radial pulse temporarily, most often as a result of swelling and not direct brachial artery injury. Fracture reduction, avoiding flexing the elbow more than 90 degrees, and elevating the arm help prevent secondary obstruction to arterial flow. Nerve injuries occur in approximately 10% of these injuries, but the incidence increases to a range of 20% to 50% with increasing severity of fracture displacement. ^, The anterior interosseous nerve is the most commonly injured, followed by the radial, median, and ulnar nerves. Most deficits seen at the time of injury are neurapraxias that resolve with rest and conservative management. Motor function returns within 7 to 12 weeks, whereas recovery of sensation may take over 6 months, though the recovery of injuries with multiple nerve injuries may take longer than that of isolated nerve injuries. ^,

Diagnostic testing of extension-type supracondylar fractures

Two diagnostic aids in evaluating for possible supracondylar fractures include using the anterior humeral line and evaluation of Baumann’s angle. The anterior humeral line is a line drawn on a lateral radiograph along the anterior surface of the humerus through the elbow. Normally, this line transects the middle third of the capitellum ( Fig. 44.12 ). With an extension supracondylar fracture, this line either transects the anterior third of the capitellum or passes entirely anterior to it. An abnormal relationship between the anterior-humeral line and capitellum may be the only radiographic evidence of a minimally displaced supracondylar fracture and is a presumptive finding of a fracture. Baumann’s angle is the intersection of a line drawn on the anteroposterior film through the midshaft of the humerus and the growth plate of the capitellum defines an angle of approximately 75 degrees ( Fig. 44.13 ). Radiographic evaluation of the elbow in children is challenging because of the presence of multiple ossification centers ( Fig. 44.14 ). Comparison views of the uninjured elbow are often helpful in distinguishing fractures from the normal epiphyses and ossification centers. Table 44.2 lists the typical age of first appearance and fusion of ossification centers.

Based on radiographic findings, supracondylar fractures are classified into four types: type I, minimal or no displacement; type IIA, displaced fracture, posterior cortex intact with no rotational component; type IIB, displaced fracture, posterior cortex intact with a rotational component; type III, totally displaced fracture, anterior and posterior cortex disrupted; and type IV, multidirectionally unstable due to complete circumferential periosteal disruption.

Management and disposition of extension type supracondylar fractures

Current treatment recommendations for supracondylar fractures from the American Academy of Orthopedic Surgeons remain based on the modified Gartland classification ( Box 44.1 ). Nondisplaced extension supracondylar fractures (type I) are immobilized primarily for comfort and protection, because they are inherently stable. They are treated in a splint or cast flexed to 75 to 80 degrees with the forearm in neutral rotation. Protected active range of motion is begun in approximately 3 weeks. Even without definite radiographic findings, a child with localized tenderness consistent with a supracondylar fracture should be splinted and referred for follow-up examination within 24 to 48 hours. A plain radiograph performed a few weeks after the injury may reveal periosteal new bone formation in the supracondylar region. Patients with a type I fracture can be discharged safely from the ED with instructions to elevate the extremity, apply ice, and have a follow-up evaluation in 1 to 2 days. Fractures that require manipulation usually warrant admission to the hospital to ensure compliance and for neurovascular monitoring. Minimally displaced (type II) fractures that are stable after reduction can be treated with splinting or casting with the elbow flexed. We recommend flexion to 110 to 120 degrees for this injury. This position uses the intact posterior periosteum as a tension band to hold the reduction; however, if swelling or circulatory obstruction prevents this amount of flexion, it should not be used. The greater the flexion at the elbow, the greater is the chance of vascular impairment. When swelling peaks at 24 to 48 hours, the risk of vascular obstruction and compartment syndrome is highest. Occasionally, these injuries require percutaneous pinning to maintain stability, especially if a significant rotational component is present. Percutaneous pinning of fractures after reduction has grown in popularity in recent years and is recommended for type IIB fractures with some studies showing better outcomes with pinning than without. ^, Type III totally displaced fractures generally are the result of more severe injuries that produce more swelling than type I or type II injuries. Displacement necessitates the reestablishment of length, increases the chance of varus deformity, and increases the chances of interposed soft tissues and neurovascular injury. For all these reasons, patients with type III fractures require emergency orthopedic consultation in the ED and should be admitted to the hospital for frequent neurovascular checks and closed reduction and percutaneous pinning. Open reduction may be necessary if closed reduction is unsuccessful. Reduction in the ED is indicated only when the displaced fracture is associated with vascular compromise that threatens the viability of the extremity. Under these conditions, closed reduction should be attempted. After appropriate procedural sedation, an assistant fixes the arm of the patient. The clinician grasps the patient’s wrist and applies steady, firm traction in line with the long axis of the limb ( Fig. 44.15A ). The forearm is kept in the neutral, thumb-up position. While traction is maintained, correction of any medial or lateral displacement is accomplished with the other hand at the elbow (see Fig. 44.15B ). If the distal fragment is displaced laterally, it is pushed inward; if it is displaced medially, it is pushed outward. After the length has been restored and the angular deformity has been corrected, the thumb of the free hand is placed over the anterior surface of the proximal fragment with the fingers behind the olecranon. While traction is maintained, the elbow is gently flexed to just beyond 90 degrees (see Fig. 44.15C ). Angulation is corrected to a normal carrying angle. Only one attempt should be made at this manipulation technique. Multiple attempts increase the likelihood of neurovascular injury and swelling. If reduction is unsuccessful, simple traction on the extended elbow may restore vascular supply. When reduction is performed, follow-up radiographs are obtained to ensure adequate reduction and neurovascular function is checked at frequent (hourly) intervals. Cylinder casts are not applied initially because they increase the risk of forearm ischemia; a posterior plaster splint provides safe and adequate immobilization. Type IV injuries require emergent orthopedic consultation for operative intervention. These injuries represent a surgical challenge, but recent studies show that a satisfactory outcome can be achieved.

Flexion type supracondylar fractures

Management of flexion type supracondylar fractures

For flexion-type supracondylar injuries, when the posterior periosteum is torn, the anterior periosteum functions as a tension band with the arm in extension. In type I fracture, the periosteum is minimally displaced. These injuries do not need to be immobilized in extension. The elbow can be comfortably flexed and should be immobilized in a splint as with extension injuries. Type II and III injuries require emergent orthopedic consultation. Type II injuries are manipulated into extension and then either in a long arm cast or with percutaneous pins. Type III injuries are treated with closed reduction and percutaneous pinning but will require open reduction if closed reduction fails ( Fig. 44.16 ).