Chapter 270: Elbow and Forearm Injuries

Articulations of the distal humerus and proximal ulna and radius form the elbow joint (Figure 270-1).

The epicondyles are nonarticulating surfaces that serve as sites of origin for forearm, wrist, and digit flexors and pronators (medial), and extensors and supinators (lateral). Medially, the trochlea articulates with the olecranon to form a uniaxial hinge joint. Laterally, the capitellum abuts the radial head to form a pivot joint. Between the condyles, the coronoid fossa is anterior, and the olecranon fossa is posterior. These allow for full flexion and extension of the ulna. The radial fossa lies proximal to the capitellum anteriorly and permits full flexion of the radius.

The radius and ulna are joined together along their entire length by a fibrous interosseous membrane, and articulate only at their ends to form the complex proximal and distal radioulnar joints. The ulna is a comparatively straight bone, whereas the radius has an important outward bowing. During the motions of supination and pronation, the radius rotates around the relatively fixed ulna. Because these bones have such a close relationship to one another, injury to one will have a direct impact on the other. A displaced or angulated fracture of one bone typically disrupts the other or causes a dislocation at the proximal or distal radioulnar joint.

Several important neurovascular structures lie in close proximity to the distal humerus, and evaluation of their function is essential. These include the brachial artery, palpable just medial to the distal biceps tendon in the antecubital fossa, and the radial, median, and ulnar nerves (Table 270-1).

The neuroanatomy is best understood by appreciating the neural control of basic wrist and finger movement (Figure 270-2). The radial nerve travels over the lateral epicondyle and supplies the muscles of wrist extension before it branches off into the posterior interosseous nerve. This deep branch travels around the proximal radius and through the supinator muscle and controls the muscles of finger and thumb extension. The remainder of the radial nerve lies adjacent to the radial artery. This superficial branch is purely sensory and innervates the dorsal aspect of the hand from the thumb to the radial half of the ring finger. Thus, the proximal portion of the radial nerve controls the more proximal function of wrist extension, the deep branch (posterior interosseous nerve) controls the more distal function of finger extension, and the superficial branch is purely sensory. Therefore, an isolated injury to the posterior interosseous branch affects finger extension but spares wrist extension and sensation to the dorsum of the hand.

The median nerve supplies the muscles of wrist and finger flexion and sensation over the volar surface of the hand from the thumb to the radial half of the ring finger, including the dorsal tips of the thumb and index and middle fingers. The proximal portion of the median nerve innervates the muscles that control wrist flexion and the flexor digitorum superficialis before it gives off the anterior interosseous nerve. This branch controls portions of the remaining deep finger flexors. The remaining portion of the median nerve provides sensation to most of the volar surface of the hand in addition to controlling the thenar muscles of the thumb via a separate motor branch (recurrent branch of the median nerve).

The ulnar nerve provides innervation to forearm muscles and controls the intrinsic muscles of the hand while providing sensation to the little finger and the ulnar half of the ring finger. Proximal to the elbow, the ulnar nerve courses under a ligamentous band called the arcade of Struthers prior to entering the cubital tunnel posterior to the medial epicondyle. These are two sites where the nerve can become entrapped, leading to ulnar neuropathy syndromes. The ulnar nerve is palpable as a cord in the cubital tunnel and is vulnerable to injury with trauma over this area.

The biceps muscle has two proximal heads (Figure 270-3). The long head originates at both the supraglenoid tubercle of the scapula and the superior labrum of the glenohumeral joint, and then travels through the capsule of the shoulder and along the intertubercular (bicipital) groove of the humerus. The short head originates at the coracoid process of the scapula. The distal attachments are to the radial tuberosity by the distal biceps tendon and the forearm by the bicipital aponeurosis. A bicipitoradial bursa lies adjacent to the radial tuberosity. The biceps muscle is innervated by the musculocutaneous nerve (C5 and C6) and functions to flex the supinated forearm and supinate the flexed forearm.

The brachialis muscle lies deep to the biceps muscle. It originates on the distal anterior humerus and inserts on the ulnar tuberosity of the proximal ulna. The brachialis muscle is innervated by both the musculocutaneous and radial nerves (C5, C6, C7, and C8) and is the primary flexor of the forearm.

The triceps muscle has three proximal heads (Figure 270-4): a long head originating from the infraglenoid tubercle of the scapula; a lateral head on the posterior surface of the humerus superior to the radial (spiral) groove; and a medial head inferior to the radial groove. The triceps inserts at the olecranon. A subtendinous bursa separates the triceps from the olecranon, and a subcutaneous bursa lies just distal to the tendinous insertion. The latter frequently becomes inflamed. The triceps muscle is innervated by the radial nerve (C6, C7, and C8) and is the sole extensor of the forearm. Additionally, the triceps aids extension and adduction of the arm, and the long head stabilizes the head of the humerus in abduction.

The intrinsic forearm muscles include the brachioradialis, pronator teres, pronator quadratus, anconeus, and supinator (Figure 270-5). The brachioradialis muscle originates at the lateral condyle and assists with forearm flexion. The pronator teres muscle has two proximal heads that originate from the medial epicondyle and the proximal ulna; it pronates and flexes the forearm. The pronator quadratus muscle originates from the distal ulna and is the primary pronator of the forearm. The anconeus muscle originates from the posterior lateral epicondyle and has trivial function in extending the forearm. Lastly, the supinator muscle originates from the posterior medial ulna and supinates the forearm with the biceps muscle. The deep branch of the radial nerve (posterior interosseous nerve) pierces the supinator muscle after branching off of the proximal segment of the radial nerve. Thus, a compression neuropathy to the posterior interosseous nerve can occur at this level (Figure 270-6).

HISTORY

A thorough history is essential for determining the correct diagnosis in a patient with elbow or forearm pain. Onset of symptoms, mechanism of injury, exact location of pain, and associated symptoms such as numbness, weakness, or distal wrist and hand complaints are important elements to obtain. Most acute traumatic injuries to the elbow and forearm occur due to a fall onto an outstretched hand or a direct blow. Chronic overuse injuries should correlate with preceding activity involving a repetitive motion. A history of arthritides may point to a systemic disorder such as lupus, rheumatoid arthritis, or gout.

PHYSICAL EXAMINATION

General examination of the elbow and forearm should include inspection for gross deformity, soft tissue swelling such as bursitis, or open wounds. Assess range of motion of the elbow in flexion, extension, pronation, and supination. Inability to fully extend the elbow is correlated with the presence of a fracture.¹ Strength testing against resistance should also include wrist flexion and extension. Carefully assess radial, median, and ulnar nerve function. The single best test of radial nerve motor function is to have the patient extend both the wrist and fingers against resistance (Table 270-1). Test sensation with two-point discrimination over the dorsum of the thumb index web space. Evaluate the median nerve by assessing its distal branches. A simple test of anterior interosseous nerve function is the ability to make a circle, or "OK" sign, with the thumb and index finger. Abduction of the thumb against resistance (recurrent branch of the median nerve) and sensory testing over the tip of the index finger complete the evaluation of the median nerve. The easiest way to test ulnar nerve function is to have the patient spread the fingers apart against resistance. Sensation is tested over the tip of the fifth digit.

IMAGING

Initial imaging studies should include anteroposterior and lateral views of the elbow, and anteroposterior, lateral, and oblique views of the humerus and forearm. If a distal forearm injury is present, anteroposterior, lateral, and oblique views of the wrist instead of the humerus should be obtained. Attempts to derive a clinical decision rule to guide imaging decisions for the elbow, similar to published ankle and knee imaging rules, have so far produced conflicting data.^1,2,3

On lateral films of the elbow, a line drawn straight through the center of the radial shaft should bisect the radial head and capitellum (radiocapitellar line) (Figure 270-7). Loss of this relationship should raise suspicion for an occult radius fracture or dislocation. A line drawn straight along the anterior border of the humerus should transect the posterior two thirds of the capitellum (anterior humeral line) (Figure 270-8). Abnormal extension of the line through the anterior one third of the capitellum suggests a distal humerus (in adults) or supracondylar fracture (in children). A small anterior fat pad may be a normal finding. Large anterior and any posterior fat pads are always abnormal and indicate the presence of a joint effusion (Figure 270-9).

CT imaging provides greater radiographic detail when evaluating certain elbow fractures, particularly coronoid and comminuted intra-articular fractures. MRI is useful in the evaluation of soft tissue injuries such as ligament or tendon ruptures but has limited value in the acute setting. Bedside US can demonstrate effusions and tendon injury but requires operator skill.^4,5

Consult an orthopedic surgeon immediately for open fractures, irreducible dislocations, injuries resulting in a grossly unsTable elbow joint, or vascular injury with signs of ischemia or uncontrolled hemorrhage. All other injuries may be referred for follow-up within 1 to 2 days for operative planning or up to a week for nonoperative treatment. Table 270-2 outlines guidelines for ED immobilization and appropriate orthopedic consult time frames for the conditions discussed in this chapter.

BICEPS TENDON RUPTURE

Of all injuries to the biceps, the vast majority are proximal, and nearly all involve the proximal long head. Injuries are usually the result of repetitive microtrauma and overuse. Steroids, whether injected locally or used systemically, can accelerate the breakdown of tendons. Biceps tendon rupture usually occurs when there is sudden or prolonged contraction against resistance in middle-aged and older individuals with a history of chronic bicipital tenosynovitis. A snap or pop is usually described, and pain is present in the anterior shoulder. Examination of the anterior shoulder will reveal swelling, tenderness, and often crepitus over the bicipital groove. Ecchymosis may extend the entire length of the biceps. Flexion of the elbow will elicit pain and may produce a midarm "ball," which represents the distally retracted biceps muscle. Comparing arms for symmetry helps. Loss of strength is minimal due to the function of the brachialis and supinator. Avulsion fractures occasionally occur, so radiographs of the shoulder should be obtained.

ED treatment includes sling, ice, analgesics, and referral to an orthopedic surgeon for definitive care. Surgical repair is usually recommended for young, active patients. A conservative approach with immobilization may be adequate for elderly patients whose activities of daily living are not significantly compromised by the injury.

Distal biceps injuries are less common than proximal injuries.^6,7 Complete ruptures of the tendon are most common in middle-aged men and usually involve the dominant extremity. Partial tears are seen in men and women. Mechanism of injury is typically a sudden eccentric (extension) load applied to a flexed elbow. In ruptures of the distal biceps, pain is felt in the antecubital fossa, with swelling, ecchymosis, and tenderness to palpation noted on examination. A distal rupture is indicated by a palpable defect in the antecubital fossa and a midarm "ball." Strength loss, especially supination, is usually greater than with proximal ruptures. The biceps squeeze test, similar to the Thompson test for assessing Achilles tendon rupture, can detect biceps rupture.⁸ With the patient seated and the forearm at 60 to 80 degrees of flexion, place one hand on the muscle belly of the biceps brachii and the other hand on the myotendinous junction, and squeeze with both hands. The squeeze should result in forearm supination, indicating an intact biceps. Lack of supination is considered a positive test, indicating rupture of the distal biceps brachii. To perform the hook test,⁹ flex the patient's elbow to 90 degrees, and during active supination, if the biceps tendon is intact, the examiner can "hook" the index finger under the distal biceps tendon in the antecubital fossa. Obtain elbow radiographs to search for an associated avulsion fracture. Although most complete distal ruptures are diagnosed clinically, MRI and US can aid in confirming the diagnosis of partial tears.^10,11

ED treatment includes sling, ice, analgesics, and referral to an orthopedic surgeon for definitive care. Without surgical repair of complete ruptures, supination strength is decreased by approximately 50% and flexion strength by almost 30%.^12,13

TRICEPS TENDON RUPTURE

Injury to the triceps is rare and almost always occurs distally.¹⁴ Ruptures result from either a fall on an outstretched hand causing a forceful flexion of an extended elbow or a direct blow to the olecranon. Spontaneous ruptures from systemic illnesses, particularly hyperparathyroidism and chronic renal failure requiring hemodialysis, have also been reported.^15,16 Triceps rupture usually causes pain in the posterior elbow. Examination of the elbow reveals swelling and tenderness posteriorly just proximal to the olecranon. A sulcus with a more proximal mass, representing the retracted triceps muscle, may be palpated. With partial tears, some degree of function remains; however, with complete ruptures, the ability to extend the elbow is lost. A modified Thompson test can be used to evaluate triceps function. The upper extremity is positioned such that the arm is supported and the forearm is hanging in a relaxed position with 90 degrees of flexion. Squeezing the triceps muscle should produce extension of the forearm unless a complete rupture is present. Radiographs of the elbow are needed because avulsion fractures of the olecranon are common. US and MRI may aid in diagnosis, especially of partial tears.

ED treatment includes sling, ice, analgesics, and referral to an orthopedic surgeon for definitive care. Complete ruptures require surgical repair, whereas most partial tears can be treated conservatively with immobilization.

LATERAL EPICONDYLITIS

The lateral epicondyle serves as the origin for wrist and digit extensors and forearm supinators. Lateral epicondylitis, or "tennis elbow," is an overuse syndrome affecting these soft tissues. Although the condition is often seen in tennis players, it can arise as a result of any repetitive movement involving these muscle groups. The diagnosis is made clinically by tenderness over the lateral epicondyle and pain with resisted wrist and digit extension and forearm supination. Treatment is usually conservative, with rest, ice, anti-inflammatory medications, and immobilization, often via a counterforce brace. Physical therapy consisting of forearm stretching and strengthening exercises has been proven to be a useful adjunct in addition to the above.^17,18 Corticosteroid injections can provide short-term relief of symptoms but have been shown to result in higher recurrence rates at 1 year compared to conservative measures.^17,18 Surgery may be indicated for refractory cases.

MEDIAL EPICONDYLITIS

The less common counterpart to lateral epicondylitis is medial epicondylitis ("golfer's elbow"). As with lateral epicondylitis, the diagnosis is made clinically, with tenderness over the medial epicondyle and pain with resisted wrist and digit flexion and forearm pronation, as these are the muscle groups affected. In addition, patients may develop an ulnar neuropathy, given the proximity of the ulnar nerve to the medial epicondyle. Treatment is similar to that of lateral epicondylitis, with rest, ice, anti-inflammatory medications, bracing, and physical therapy.

The elbow is one of the more sTable joints. The muscular attachments, lateral collateral ligament, and medial ulnar collateral ligament augment its inherent stability in the flexion-extension plane. Despite this, dislocations of the elbow are commonly seen and rank third in large-joint dislocations, after glenohumeral and patellofemoral dislocations. Possible fractures of the coronoid process, radial head, medial epicondyle, and olecranon complicate the treatment of elbow dislocations. The "terrible triad" injury describes an unsTable joint consisting of an elbow dislocation coupled with fractures of the radial head and coronoid. This injury creates an unsTable joint and requires surgical repair after initial reduction.

Elbow dislocations include five types: posterior, anterior, medial, lateral, and divergent (Figure 270-10). Some dislocations may involve a combination of the above based on the direction of force applied during the injury. Approximately 90% of all elbow dislocations are posterolateral.¹⁹ The mechanism of injury is usually due to a fall on an outstretched hand.

Clinically, the patient presents with the elbow in 45 degrees of flexion. The olecranon is prominent posteriorly, and the deformity resembles a displaced supracondylar fracture. If the patient is seen immediately after the injury, the bony landmarks can be identified. Later, however, the swelling may be quite severe, with no possibility of evaluating the injury topographically. The first priority of care is to assess the neurovascular status of structures most vulnerable to entrapment, namely the brachial artery and the ulnar, radial, and median nerves. Perform neurovascular examination before and after manipulation, because neurovascular complications (most frequently the ulnar nerve) occur in 8% to 21% of patients. Vascular complications (most frequently the brachial artery) occur in 5% to 13% of elbow dislocations.²⁰ Absence of a radial pulse before reduction, an open dislocation, and systemic injuries (such as those of the head, chest, and abdomen) are associated with arterial injury.^21,22 If vascular injury is suspected, then angiography may be required to assess the extent of injury and need for repair.

On the lateral radiograph, both the ulna and radius are displaced posteriorly (Figure 270-11). In the anteroposterior view, there may be lateral or medial displacement, with the ulna and radius in their normal relationship to each other. Assess for associated fractures, particularly of the coronoid process and radial head. In a child, an associated fracture of the medial epicondyle is common.

Due to the amount of force that is necessary to reduce a dislocated elbow, success is often dependent on adequate analgesia and muscular relaxation. This may require the use of intravenous analgesics or procedural sedation, particularly in children. As an alternative to procedural sedation or intravenous analgesia, anecdotal success has been reported using intra-articular lidocaine to provide regional anesthesia for closed reduction of dislocated elbows, similar to the well-described use of intra-articular blocks for reduction of anterior glenohumeral shoulder dislocations.^23,24 In the elbow, intra-articular lidocaine is effective for postoperative pain control following arthroscopic procedures in adults and supracondylar fracture repairs in children.^25,26 Regardless of the type of analgesia used, ensure appropriate patient comfort prior to attempting closed reduction.

Closed reduction can be accomplished by several methods. In the first two-person reduction technique, position the patient supine and apply gentle longitudinal traction on the wrist and forearm with one hand while an assistant applies a stabilizing countertraction force on the upper arm (Figure 270-12). First, correct any medial or lateral displacement with the other hand. Then apply downward pressure to the proximal forearm with the other hand to help disengage the coronoid process from the olecranon fossa. Continue distal traction, and flex the elbow. In the second two-person technique, position the patient prone with the arm abducted and the elbow slightly flexed. The patient may also be positioned supine with the affected arm adducted across the torso and the elbow slightly flexed (Figure 270-13). Have an assistant apply longitudinal traction on the wrist and forearm. Then, grasp the elbow, positioning both thumbs on the olecranon, and apply firm pressure against the olecranon to push it up and over the trochlea and back into anatomic position. Apply countertraction with the fingers against the distal humerus. The last technique is a modification of the Stimson hanging technique used in shoulder reductions (Figure 270-14). One benefit of this technique is that it can be performed by a single provider. Place the patient prone with the elbow flexed over the edge of the stretcher. Support the humerus proximal to the elbow with a folded blanket or pillow. Suspend 5-lb weights from the wrist. The patient's elbow should reduce over a period of several minutes. Gentle manipulation may be applied to the olecranon to aid reduction.

With reduction, a palpable "clunk" is felt as the olecranon is seated in the humeral articular surface (trochlea). Then move the elbow through its full range of motion to assess stability. Inability to maintain reduction through full range of motion necessitates orthopedic consultation for surgical repair. If full and smooth passive range of motion is not possible, examine the postreduction radiograph for entrapment of the medial epicondyle, especially common in children, or other intra-articular fragments. If the elbow remains reduced through full range-of-motion testing, assess medial and lateral stability with gentle valgus and varus stress on the elbow in full extension. Valgus (medial) laxity is more common and suggests disruption of the medial (ulnar) collateral ligament complex, which is the primary stabilizing structure of the elbow joint against valgus forces. Medial instability that stabilizes with 90 degrees of flexion and maximal pronation of the forearm should be splinted in this position and referred for follow-up.²⁷ Instability that cannot be stabilized with flexion and pronation suggests associated fractures or more significant disruption of the capsule and ligaments. In this case orthopedic consultation for surgical repair is necessary.

After reduction, immobilize sTable dislocations in a long arm posterior splint with the elbow in slightly less than 90 degrees of flexion and the forearm in mild pronation. Obtain a neurovascular follow-up examination the following day. Treatment with an early range-of-motion program after 1 week of splinting generally leads to favorable results.

Appropriate treatment of elbow dislocations requires adequate reduction and recognition of neurovascular complications, associated fractures, and postreduction instability. If there is any question of neurovascular compromise, then consider admitting the patient for observation. Obtain emergency orthopedic consultation for irreducible dislocations, neurovascular compromise, postreduction instability, associated fractures, and open dislocations. Potential late complications include posttraumatic stiffness, posterolateral joint instability, ectopic ossification, and occult distal radioulnar joint disruption.

Elbow fractures can be divided into those of the distal humerus, proximal ulna, and proximal radius. The distal humerus includes the condylar structures and the articular surface (trochlea and capitellum). The proximal ulna includes the coronoid process and olecranon, and the proximal radius is essentially the radial head.

Radiographs of fractures about the elbow may reveal abnormal fat pads (Figure 270-9).²⁸ Normally, a posterior fat pad is not visible, and an anterior fat pad may be visible as a thin lucent stripe. With injury, fat from the olecranon fossa is displaced posteriorly (posterior fat pad), and the anterior fat pad may become quite prominent ("sail sign") due to hemarthrosis. Abnormal fat pads may also be seen with nontraumatic joint effusions. Furthermore, they may be absent in severe trauma that disrupts the joint capsule and allows intra-articular fluid extravasation. In some nondisplaced fractures, the fracture line may not be seen, with the fat pad sign being the only evidence of injury. Treatment is initiated as though a fracture were identified, with splint immobilization and orthopedic consultation.

DISTAL HUMERUS FRACTURES

Routine ED care of nondisplaced distal humerus fractures with normal neurovascular function includes immobilization, ice, elevation, analgesics, and orthopedic referral. Displaced fractures or those with neurovascular compromise require immediate orthopedic consultation. See chapter 271, "Shoulder and Humerus Injuries," for a detailed discussion of shoulder and humerus injuries.

SUPRACONDYLAR FRACTURES

Supracondylar fractures are the most common fracture about the elbow in children between 5 and 10 years of age, but can occur in adults, especially as a result of high-velocity injuries. Fractures can be either extension type (>95%), which are displaced posteriorly, or flexion type (<5%), which are displaced anteriorly. Treatment largely depends on the degree of displacement of the distal fragment.

EXTENSION-TYPE SUPRACONDYLAR FRACTURES

Injuries most often occur with a fall on an outstretched hand with the elbow in full extension. The patient will have significant edema and tenderness at the elbow, a prominent olecranon, and a depression proximal to the elbow. The appearance may be easily mistaken for a posterior elbow dislocation. Nondisplaced fractures may be subtle and diagnosed only by the presence of a posterior fat pad, anterior "sail sign," or disruption to the normal path of the anterior humeral line. Initially treat with immobilization using a long arm posterior splint, keeping the elbow at 90 degrees of flexion and the forearm in neutral rotation, followed by outpatient referral for casting. The presence of >20 degrees of angulation necessitates orthopedic consultation for reduction under anesthesia and possible pin fixation.²⁹ In displaced fractures, the anteroposterior radiograph usually reveals a transverse fracture line. More severely displaced fractures may show medial or lateral displacement or rotation along the axis of the humerus (Figure 270-15). The lateral radiograph will reveal the fracture line extending obliquely from posterior proximal to anterior distal. The distal fragment will be displaced proximally and posteriorly. Displaced fractures must be reduced and require orthopedic consultation. Indications for open reduction are vascular insufficiency with a probable entrapped brachial artery in the fracture site or an irreducible fracture. Admit patients with displaced fractures or significant soft tissue swelling for observation of neurovascular function.

FLEXION-TYPE SUPRACONDYLAR FRACTURES

Flexion-type fractures are rare. The mechanism of injury is a direct anterior force against a flexed elbow, resulting in anterior displacement of the distal fragment. Because the mechanism is direct force, these fractures are often open. Radiographs reveal an oblique fracture from anterior proximal to posterior distal. The distal fragment is anterior to the humerus. Displaced fractures must be reduced and require immediate orthopedic consultation. Indications for open reduction are vascular insufficiency with a probable entrapped brachial artery in the fracture site or an irreducible fracture. Admit patients with displaced fractures or significant soft tissue swelling for observation of neurovascular function.

COMPLICATIONS OF SUPRACONDYLAR FRACTURES

There are numerous potential complications of supracondylar fractures (Table 270-3). Neurologic complications—resulting from traction, direct trauma, or nerve ischemia—have an incidence of 7%. Posteromedial displacement may involve the radial nerve, and posterolateral displacement usually affects the median nerve. Ulnar nerve injuries are uncommon, with the highest incidence reported from pin placement. However, a high incidence has been noted of anterior interosseous nerve injuries with supracondylar fractures. This nerve arises from the median nerve. The mechanism of injury is usually traction or contusion. Complete transection is rare, and entrapment within the fracture occurs only occasionally. Because there is no sensory component to the anterior interosseous nerve, identification of the injury can be made only by motor testing, which consists of flexion at the index finger distal interphalangeal and thumb interphalangeal joints (making the "OK" sign). Patients usually regain full flexion and strength after 4 to 17 weeks.³⁰

Acute vascular injuries must always be suspected in patients with supracondylar fractures. Absence of a radial pulse is common in children and, in the majority of published cases, is an indicator of brachial artery injury, even if the hand appears warm, pink, and well perfused.³¹ Injury can be due to a partial or complete transection, an intimal tear and thrombosis, or entrapment within the fracture fragment of the brachial artery. Treatment of supracondylar fractures with absent radial pulse begins with closed reduction and percutaneous pinning. Extremities still without a pulse despite adequate reduction warrant more aggressive vascular exploration and repair.

The most serious complication is a compartment syndrome of the forearm, also known as Volkmann's ischemic contracture. This classically occurs following a supracondylar fracture. Postischemic swelling, producing increased pressure within the enclosed osteofascial forearm compartment, reduces capillary blood perfusion below the level necessary for tissue viability. If unrelieved, the end result is muscle and nerve necrosis and eventual replacement by fibrotic tissue, producing a contracture. Refusal to open the hand in children, pain with passive extension of the fingers, and forearm tenderness are signs of impending Volkmann's ischemia. It is now well understood that the mere lack of a radial pulse does not indicate ischemia unless accompanied by these signs. Extremities with signs of ischemia are taken emergently to the operating room for fasciotomy and brachial artery exploration.

INTERCONDYLAR FRACTURES

Intercondylar fractures, in which the condylar fragments are separated, are much more common in adults than in children. Assume any distal humerus fracture in an adult to be intercondylar rather than supracondylar. The mechanism of injury is a force directed against the posterior elbow, driving the olecranon against the humeral articular surface, separating the condyles and producing the typical fracture. Carefully search for a fracture line separating the condyles from each other and from the humerus. By definition, all intercondylar fractures involve the articular surface. CT imaging is useful for identifying comminuted fractures and for planning operative therapy for displaced fractures. Treatment is dependent on the amount of displacement of the fracture fragments.

Nondisplaced intercondylar fractures are sTable and can be treated initially with immobilization in a long arm posterior splint with the elbow flexed at 90 degrees and the forearm in neutral position. Treatment of displaced, rotated, or comminuted fractures is often directed at reestablishing articular surface congruity. If this cannot be achieved by closed methods, then the integrity of the articular surface is restored by an open reduction and fixation. In older patients with severely comminuted injuries, elbow replacement may be considered.³² As in supracondylar fractures, admit patients with severe edema or displaced fractures.

EPICONDYLE FRACTURES

Lateral epicondyle fractures almost never occur, because the anatomic position of the condyle reduces its exposure to direct blows, resulting instead in fractures of the lateral condyle. When they do occur, lateral epicondyle fractures are usually avulsion fractures and may be treated by long arm posterior mold, with the elbow flexed to 90 degrees and the forearm in supination, and orthopedic referral.

Isolated medial epicondyle fractures are considered extra-articular injuries and usually occur in children and adolescents. Mechanisms include a posterior elbow dislocation, repeated valgus stress, such as throwing a baseball (Little League elbow), or a direct blow. If there is an associated tear of the medial (ulnar) collateral ligament, the epicondyle itself may become entrapped in the joint space. Patients present with pain over the medial elbow that is exacerbated by supination of the forearm and flexion of the forearm, wrist, and digits. Edema and tenderness are noted in the same area. Standard radiographs are obtained with special attention to any intra-articular fragment. Carefully test ulnar nerve function. Nondisplaced or minimally displaced medial epicondyle fractures can be treated nonoperatively, with early range of motion. There is an increasing trend toward operative treatment for these fractures due to significantly increased odds of bony union with fixation.³³ Open fractures, unsTable joints, fragment displacement >5 mm, and an intra-articular fragment are well-described indications for surgical treatment with internal fixation. ED treatment consists of long arm posterior splint immobilization, with the forearm in flexion and pronation, and orthopedic referral.

Complications of lateral and medial epicondyle fractures are frequent and include nonunion, cubitus valgus or varus deformity, ulnar nerve palsy, and avascular necrosis.³⁴ Careful neurovascular assessment is required for these injuries. Because surgical treatment is generally preferred, orthopedic consultation is recommended for both lateral and medial epicondyle fractures.

CONDYLE FRACTURES

Lateral condyle fractures occur in children and are more common than their medial counterpart.³⁵ Lateral condyle fractures result from a direct blow to the lateral elbow or from varus stress with the forearm extended, as in a fall on an outstretched hand. Patients complain of pain in the lateral elbow, and swelling is noted in the same area.

Medial condyle fractures are uncommon and are mostly limited to children. Mechanism of injury is from either a transmitted force from the ulna, such as a fall on an outstretched hand, or excessive valgus stress. Pain and swelling medially are prominent findings. The injury is often confused with the more common medial epicondyle fracture for two reasons. First, the mechanism and examination findings are similar. Second, because the trochlea ossification center does not appear until age 9 to 10 years old, it is often missed on radiographs.

ED care of nondisplaced lateral and medial condyle fractures with normal neurovascular function includes long arm posterior splint immobilization, ice, elevation, analgesics, and orthopedic referral. Follow-up imaging every 2 weeks is recommended due to the risk of late displacement, which is treated with surgical fixation. Displaced fractures or those with neurovascular compromise require immediate orthopedic consultation. Complications include malunion with resultant cubital valgus or varus deformity, delayed ulnar nerve injury, and arthritis.

ARTICULAR SURFACE FRACTURES

TROCHLEA FRACTURES

Isolated trochlea fractures are rare, and they are more often associated with other elbow injuries, such as posterior elbow dislocations. Physical findings usually include swelling, tenderness, and limited movement of the elbow joint. Radiographic findings can be subtle, and CT or MRI may be required for diagnosis. ED treatment includes long arm posterior splint immobilization and orthopedic consultation because this is an articular surface injury and surgical repair is usually indicated. Complications are common and include limited flexion and extension, elbow joint instability, avascular necrosis, nonunion, and arthritis.

CAPITELLUM FRACTURES

Isolated capitellum fractures are rare. They are usually associated with radial head fractures. Pain and tenderness are present over the lateral elbow, and examination reveals swelling, lateral tenderness, and limitation of flexion and extension. If pain and tenderness are present medially, then suspect injury to the medial collateral ligament. Radiographic findings may be subtle and are best seen on a lateral view. The capitellum has no tendinous or ligamentous attachments, so many fractures are nondisplaced. A radial head–capitellum view can be helpful in addition to standard anteroposterior and lateral views. CT imaging is useful for diagnosis. ED treatment is similar to that of trochlea fractures. Definitive care is surgical, and complications are similar to those of trochlea fractures.

PROXIMAL ULNA FRACTURES

The distal humerus articulates with the proximal ulna to form a uniaxial hinge joint, which allows flexion and extension of the forearm and provides some intrinsic stability. The trochlea of the humerus rests in the greater sigmoid (semilunar) notch of the ulna. The anterior projection of the notch is the coronoid, and the posterior prominence, which is easily palpable, is the olecranon. The brachialis muscle inserts at the coronoid, and the triceps muscle inserts at the olecranon. Nearly all proximal ulna fractures are considered intra-articular, with the exception of a proximal olecranon chip fracture.

CORONOID FRACTURES

Coronoid fractures are usually associated with posterior elbow dislocations as the trochlea is driven into the coronoid. A coronoid fracture can rarely occur as an isolated injury secondary to elbow hyperextension.³⁶ There is pain, swelling, and tenderness over the antecubital fossa. Radiographic visualization is best with lateral and oblique films. Often CT is needed to make the diagnosis.

ED treatment should include long arm posterior splint immobilization with the elbow in flexion and the forearm in supination, ice, elevation, analgesics, and referral to an orthopedic surgeon within 24 hours. Conservative treatment of nondisplaced coronoid fractures remains controversial, and early orthopedic referral is indicated. Displaced fractures or those associated with joint instability require open reduction and internal fixation and frequently have poor outcomes.

OLECRANON FRACTURES

The olecranon is usually fractured by direct trauma or by a fall with forced hyperextension of the elbow. Olecranon fractures are quite common and represent up to 10% of upper extremity fractures.³⁷ Associated injuries are common, including open fractures, dislocations, other fractures (especially of the radial head), and ulnar nerve injury. Pain is present over the posterior elbow, and examination reveals swelling, tenderness, and occasionally crepitus. Because the triceps muscle inserts at the olecranon, triceps function is usually compromised. It is important to test forearm extension against resistance, as the patient may falsely appear to have intact forearm extension by using gravity to draw the forearm down. Ulnar nerve injury is common; therefore, a careful neurologic examination is required. Lateral radiographs offer the best view of the olecranon. In adolescents, the epiphysis ossifies by age 11 years old and fuses by age 16 years old, so comparison films and the appearance of an abnormal fat pad can aid in the diagnosis. ED treatment includes long arm posterior splint immobilization with the elbow in flexion and forearm neutral, ice, elevation, analgesics, and referral to an orthopedist within 24 hours. Stable, nondisplaced fractures with intact extensor function can be treated conservatively with immobilization. Nonoperative treatment may also be considered for poorly functioning elderly patients who would not tolerate surgery. All other olecranon fractures require surgical repair.³⁸

RADIAL HEAD FRACTURES

The radial head is located just distal to the lateral epicondyle. Pronating and supinating the forearm with the elbow flexed allows the examiner to palpate the radial head. It articulates with the capitellum and the lesser sigmoid notch of the ulna to form a pivot joint. The radial head serves as a stabilizer of the elbow against valgus stress, along with the medial collateral ligament, and against longitudinal forces.

Radial head fractures are the most common fractures of the elbow. They result from a fall on an outstretched hand causing the radial head to be driven into the capitellum. Associated injuries are common and may include capitellum, olecranon, and coronoid fractures, medial collateral ligament injury, medial epicondyle avulsion fracture secondary to valgus stress, and elbow dislocation. A specific associated injury, the Essex-Lopresti lesion, occurs when there is disruption of the triangular fibrocartilage of the wrist and the interosseous membrane between the radius and ulna, causing pain in the wrist and forearm. The result is a distal radioulnar joint dissociation, which can cause migration of the radius proximally if radial head excision is performed. Open reduction and internal fixation of the proximal radius fracture is indicated for this injury.

Radial head fractures cause pain in the lateral elbow, especially with pronation and supination of the forearm. On examination, there may be swelling laterally and tenderness with palpation of the radial head. On standard elbow radiographs, radial head fractures may be subtle (Figure 270-16). Additional images, including obliques and a radial head–capitellum view, may be helpful. Furthermore, two radiographic clues can aid in the diagnosis. The first is abnormal displacement of the radiocapitellar line away from the center of the capitellum (Figure 270-7). This is especially helpful in children whose epiphysis has not fused. The other clue is the appearance of an abnormal fat pad (Figure 270-9).

Nondisplaced fractures with no mobility restrictions can be treated conservatively with immobilization. For these, ED treatment consists of sling immobilization with the elbow in flexion, ice, elevation, analgesics, and referral to an orthopedic surgeon within 1 week. Consider aspiration of the joint hematoma in the ED to improve pain and facilitate early mobilization.³⁹ Additional pain control may be obtained with intra-articular injection of lidocaine or bupivacaine following aspiration, but this does not offer any long-term benefit over aspiration alone.⁴⁰ For displaced fractures or those with restricted range of motion, surgical repair is generally indicated, and orthopedic referral within 24 hours is needed. Complications of radial head fracture include chronic pain and restricted range of motion at the elbow.

In adults, solitary fractures of the forearm are uncommon due to the close relationship of the radius and ulna. The fibrous interconnection between the radius and ulna transmits traumatic energy above and below the injury. So, fractures usually occur at two or more sites or involve a fracture of one bone with a ligamentous injury, with or without an associated joint dislocation. Because distant structures are commonly injured, examine joints above and below the involved bones both clinically and radiologically. Be especially observant for associated injuries if there is significant angulation of the fracture.

The radius and ulna are under the influence of numerous muscle groups, such as those that supinate and pronate (Figure 270-5). The biceps brachii and the supinator insert on the proximal radius and are the powerful supinators of the forearm. The pronator teres inserts on the radial shaft and exerts a pronating force. Radius fractures that are located between these muscle groups will result in marked displacement of the radius, with supination of the proximal segment and pronation of the distal portion. However, if the fracture is distal to the insertion of the pronator teres, these forces tend to neutralize one another and result in less rotational deformity. When considering treatment of these fractures, careful attention must be paid to the maintenance of length, alignment, and angulation. Also, the lateral bow of the radius must be preserved to allow full pronation and supination after healing.

FRACTURES OF BOTH RADIUS AND ULNA

A great amount of force is necessary to fracture both the radius and the ulna. This injury occurs most often from vehicular trauma, falls from a height, or a direct blow. Force magnitude determines injury type. Moderate forces produce transverse or mildly oblique fractures. High-impact forces produce comminuted and segmental fractures (often displaced).

Nondisplaced fractures of both bones are exceedingly rare because the force necessary to produce the injury is also sufficient to displace the bones. Examination of the forearm reveals swelling, deformity, and tenderness. Carefully assess the neurovascular status. Nerve injuries can be seen with severe open fractures but are uncommon with most closed injuries. Because of the excellent collateral circulation of the forearm, vascular compromise is generally not a major problem if either the radial or ulnar circulation is intact.

The fractures are clearly visible on the radiographs. Note the degree of angulation, displacement, and shortening. Changes in rotational alignment may be subtle. Noting the normal orientation of various bony prominences of these bones can make a rough estimate of rotational alignment. On the anteroposterior view, the radial styloid and radial (bicipital) tuberosity normally point in opposite directions, whereas the ulnar styloid and coronoid process do so on the lateral view. A change in this arrangement suggests rotation malalignment. Because these bones are also oblong rather than circular in their cross-sectional appearance, a sudden change in the bone's width at the fracture site is another clue to a rotational deformity. Obtain radiographs of the wrist and elbow because of the likelihood of an associated dislocation or articular fracture.

Treatment depends on the type of fracture. Torus or greenstick fractures with minimal angulation in children can be treated with immobilization in a long arm splint. Angulation >15 degrees warrants referral for closed reduction. In younger children, treat displaced fractures with closed reduction and cast immobilization due to the continued remodeling that occurs after fracture healing. Perform closed reduction urgently in the ED by an orthopedic consultant to ensure appropriate alignment. Surgical intervention is becoming increasingly popular, although there is a lack of evidence showing improved outcomes from surgery over conservative management.^41,42 Nondisplaced fractures in adults can be immobilized with a long arm splint and referred for urgent follow up. All other fractures in adults require operative reduction and internal or external fixation, ideally within 24 to 48 hours.

Complications include reduced ability to supinate and pronate, osteomyelitis, nonunion, malunion, neurovascular injury, and compartment syndrome. Recognizing the development of a compartment syndrome is particularly important to prevent debilitating ischemic or Volkmann's contractures of the forearm. The diagnostic findings are palpable induration of the area, pain with passive movement of the fingers, and pain disproportionate to the physical findings. Loss of radial pulse is often a late finding, and presence of a radial pulse does not exclude compartment syndrome. Direct measurements of elevated compartment pressures confirm the diagnosis. Urgent fasciotomy is required, ideally within 8 hours of the onset of symptoms.

ULNA FRACTURES

ISOLATED ULNA FRACTURE (NIGHTSTICK FRACTURE)

Isolated fractures of the ulna most often result from direct blows to the forearm. A fracture resulting from the natural response to raise the forearm in defense of a blow from a club is referred to as a nightstick fracture. Nondisplaced fractures are immobilized in a splint and closely followed for subsequent displacement. A short arm cast is preferable to a long arm cast for treatment.

Fractures with >50% displacement, with >10% angulation, or that involve the proximal third of the ulna are considered unstable.⁴³ Obtain orthopedic consultation for unsTable fractures. Open reduction and internal fixation with a compression plate and screws are necessary to prevent angulation, loss of length, and rotational deformity. Assess injuries for any possible radius fracture or dislocation.

MONTEGGIA'S FRACTURE-DISLOCATION

Fracture of the proximal third of the ulna with a radial head dislocation is often referred to as Monteggia's fracture-dislocation (Figure 270-17). The associated radial head dislocation may be easily missed.⁴⁴ Missing the radial head dislocation can lead to chronic pain, limited range of motion, and, possibly, radial head excision as treatment. Monteggia's fractures can occur following a fall onto an outstretched hand or a direct blow. The most typical injury pattern seen is a diaphyseal fracture in the proximal third of the ulna with an anterior dislocation of the radial head (60% of cases). Clinically, there is considerable pain and swelling at the elbow. The radial head may be palpable in an anterolateral or posterolateral location. The forearm may appear shortened and angulated. The ulnar fracture is clearly visible and may overshadow the less obvious radial head dislocation. As a rule, the radial head normally points to the capitellum in all radiographic views of the elbow. In a Monteggia's fracture, the apex of the ulna fracture points in the direction of the radial head dislocation.

Obtain consultation with an orthopedic surgeon. Monteggia's fracture-dislocations are generally treated with open reduction and internal fixation of the ulna and closed reduction of the radial head dislocation. In children, the injury may be treated with closed reduction and long arm splinting. Complications include nonunion, recurrent dislocation, chronic pain, infection, and paralysis of the posterior interosseous nerve, a deep branch of the radial nerve.

RADIUS FRACTURES

FRACTURES OF THE PROXIMAL TWO THIRDS OF THE RADIUS

Radius fractures can be divided into those that are proximal and those that are distal to the junction of the middle and distal thirds of the bone. Excluding radial head fractures, isolated fractures of the proximal two thirds of the radius are uncommon because the radius is relatively well protected from direct blows by the ulna and surrounding forearm musculature. Nondisplaced fractures are rare and treated with cast immobilization. Fractures of the proximal two thirds of the radius are often displaced by both the force of the injury and the action of the supinators and pronators on the radius. They require internal fixation to prevent rotational deformity. Compartment syndrome is rare with these fractures. Most complications involve malunion or nonunion because of inadequate or lost reduction.

GALEAZZI'S FRACTURE-DISLOCATION

Fractures of the distal third of the radial shaft are produced by falls on the outstretched hand in forced pronation or by a direct blow. The radius, generally the distal third, is fractured along with a dislocation of the distal radioulnar joint. Galeazzi's fracture is often referred to as the reverse Monteggia's fracture. There is localized tenderness and swelling over the distal radius and wrist. The radius fracture is usually short oblique or transverse with dorsal lateral angulation. The distal radioulnar joint injury can be subtle. Radiographs may show only a slightly increased distal radioulnar joint space on the anteroposterior view. On the lateral view, the ulna is displaced dorsally. This injury is treated surgically by open reduction and internal fixation of the radius fracture. Complications include infection, nonunion, and malunion. Injuries to the ulnar nerve and anterior interosseous branch of the median nerve have been reported but usually heal spontaneously. If the radius heals with a rotational deformity, there may be pain at the distal radioulnar joint with extreme pronation and supination.

Acknowledgments: The authors wish to recognize the contributions of Harold Chin, MD, and Arthur F. Proust, MD, in previous editions of this chapter, and of Christopher Sullivan for his research and editorial assistance.