Anatomy

The elbow joint is formed by the articulation between the humerus and the radius and ulna (Fig. 6-1). The humerus widens distally to form the lateral and medial condyles. The capitellum of the lateral condyle articulates with the radial head, and the trochlea articulates with the ulna. The head of the radius also articulates with the lateral aspect of the ulna and is held in position by the orbicular ligament. Medial and lateral collateral ligaments provide additional stability.

Fig. 6-1 Bony and ligamentous anatomy of the elbow: R, Radial collateral ligament; O, orbicular ligament; B, biceps insertion; U, ulnar collateral ligament; C, capitellum; T, trochlea.

Adjacent to each condyle are the epicondyles, which are the bony attachments for many forearm muscles. The flexor–pronator muscle group takes its origin from a common tendon that attaches to the medial epicondyle, and the extensor–supinator group arises in a similar manner from the lateral epicondyle. Posteriorly, the triceps attaches to the olecranon; anteriorly, the biceps and brachialis attach to the radius and ulna, respectively.

Three major nerves cross the elbow joint on their way into the forearm. The median nerve passes deep in the antecubital fossa medial to the biceps and brachialis, and the radial nerve passes lateral to them. The ulnar nerve reaches the forearm by coursing posteriorly in a groove between the medial epicondyle and the olecranon process, where it is easily palpated. It is also vulnerable to injury in this superficial location.

Examination

The tip of the olecranon process and the epicondyles form useful bony landmarks (Fig. 6-2). When the elbow is fully extended and viewed from behind, these points form a straight, transverse line. With the elbow flexed, they form an isosceles triangle. Just distal to the lateral epicondyle lies the radial head. These two points, along with the olecranon process, form another triangle on the posterolateral aspect of the joint. This triangle is occupied by the anconeus muscle. This area usually bulges when the joint is distended by fluid and is an excellent site for joint aspiration.

Fig. 6-2 The flexed elbow from behind: T, triceps; M, medial epicondyle; U, ulnar nerve; L, lateral epicondyle; C, common extensor tendon; X, the posterolateral triangle. The isosceles triangle between the epicondyles and the olecranon (O) is altered in most fractures and dislocations of the elbow, except the supracondylar fracture, where all three points move together.

With the forearm in the supinated position, an angle is formed with the arm at the elbow joint. This is referred to as the “carrying angle” and normally measures 15 to 20 degrees. Alterations in this angle may occur following injury or infection, especially in the young, and may lead to excessive cubitus valgus or even varus (Fig. 6-3).

Fig. 6-3 Gunstock deformity (cubitus varus) of the left elbow with reversal of the carrying angle because of an old fracture with malunion.

Roentgenographic Anatomy

The roentgenographic features of the elbow are well visualized by standard anteroposterior and 90-degree flexion lateral views (Fig. 6-4). Comparison views of the opposite elbow should be obtained whenever necessary. Oblique views are helpful when the diagnosis is uncertain.

Fig. 6-4 Roentgenographic anatomy of the elbow: M, medial epicondyle; O, olecranon fossa; L, lateral epicondyle; T, trochlea; C, capitellum; U, coronoid process of the ulna, H, radial head; R, radial tuberosity. Regardless of the position of the elbow, the long axis of the radius always passes through the capitellum.

Epicondylitis

Epicondylitis is one of a large group of musculoskeletal disorders commonly termed “overuse syndromes.” Although it is often called an inflammatory condition, degeneration (tendinosis) is usually present instead, often with the development of local neovascular tissue. The condition is characterized by pain at the origin of the flexor muscles at the medial epicondyle or the extensor muscles at the lateral epicondyle. Some cases may start with a direct blow, but the cause is usually unknown. Minor tears in the tendinous attachments of these muscles are often present. The disorder is common in individuals whose activities require repeated use of the extensor or flexor mechanism of the forearm. The lateral side (“tennis elbow”) is more commonly involved. In tennis players, the backhand swing seems to be the main offender. Involvement of the medial epicondyle is often called “golfer’s elbow.”

CLINICAL FEATURES

The onset is usually gradual. A dull ache that worsens with use of the involved muscles appears over the affected epicondyle. Palm-down lifting is painful. Activities that require rotation and grasping, such as opening a jar, increase the pain. The pain often radiates into the forearm. Extension or flexion of the hand against resistance reproduces the pain at the affected epicondyle (Fig. 6-5). The point of maximum tenderness can usually be well localized by digital pressure applied about 1 cm distal to the epicondyle. The roentgenograms are usually normal, although a traction spur or calcification may be present.

Fig. 6-5 Resisted wrist dorsiflexion to test for lateral epicondylitis.

TREATMENT

Treatment is similar to that for other “musculotendinous overuse syndromes.” Rest is important, and this can frequently be obtained merely by avoiding the offending activity. Applying ice after exercise can help. A careful exercise program of gentle stretching and strengthening is begun as pain subsides (Fig. 6-6). Nonsteroidal anti-inflammatory drugs (NSAIDs) are given as necessary. Local infiltration of the affected area with 1 to 2 mL of a steroid/lidocaine mixture often provides permanent or at least long-lasting relief (Fig 6-7). The injection is placed in the area of maximum local tenderness, usually about 1 cm distal to the bony epicondyle, and may be repeated two or three times. A tennis elbow counterforce strap may also be tried. It theoretically works by dampening the force transmitted to the elbow from the hand and wrist (see Chapter 15). Extracorporeal shock wave therapy (ESWT) has even been tried in epicondylitis, but the results are inconclusive. The disease is usually self-limited, but symptoms may persist for several months before full recovery. Conservative treatment is effective in most cases. Often, spontaneous rupture of the aponeurosis probably occurs, which cures the pain, usually without any significant residual weakness. Surgery is reserved for cases that do not respond to medical management. Eventually, the recreational tennis player may simply have to decide to withdraw from the sport.

Fig. 6-6 Exercise program for tennis elbow. It should be performed daily only after pain has subsided. A and B, Wrist curls and reverse curls are performed with light weights, lifting quickly and releasing slowly. Twenty repetitions are done each time, starting with 6 ounces and progressing to 2 pounds. C and D, Stretching exercises are performed with the elbow extended. Each position is held for 5 seconds and is repeated five times. Ice is applied for 1 to 2 minutes after the exercise program.

FIG. 6-7 Soft tissue injection for lateral epicondylitis. The patient is supine, and the elbow is flexed 90 degrees. A 25-gauge needle is used. The tender spot is injected, which is usually about 1 cm distal to the bony epicondyle. Infiltrate a wide area, but try to avoid the subcutaneous tissue.

Resistant tennis elbow (posterior interosseus nerve syndrome)

It has been speculated that some cases of lateral epicondylitis that do not respond to either medical or surgical management may be caused by entrapment of a portion of the radial nerve at the elbow (radial tunnel syndrome). The symptoms are often vague. Pain over the lateral elbow may occur with tenderness and a sense of weakness. The disorder looks like tennis elbow, but the tenderness is more deep and distal. There are no sensory changes.

The diagnosis is difficult to establish in most cases. Electromyographic (EMG) studies are frequently normal. As a last resort, surgical release of the posterior interosseous nerve may be considered, but the procedure is much less effective than decompression for other more common nerve entrapments, probably because of the difficulty in confirming the diagnosis with certainty.

NOTE: Evidence-based studies suggest the following: (1) ESTW is of unproven value in reducing pain from lateral epicondylitis, and (2) cortocosteroid injections are most effective for short-term treatment of tennis elbow at 6 weeks.

Osteochondritis Dissecans

Osteochondritis dissecans is a condition in which a portion of subchondral bone undergoes avascular necrosis. This segment of bone, with its overlying articular cartilage, may partially or completely separate from the adjacent bone and even extrude into the joint to form a loose body. The disorder is most commonly seen in the knee joint, but a similar condition also occurs in the elbow, ankle, and hip joints. The cause is unknown, but it is probably traumatic in origin. Repetitive compression of the lateral elbow joint may be responsible. The condition is sometimes a cause of “Little League elbow.”

CLINICAL FEATURES

In the elbow, the disorder is most common during adolescence, and males are usually affected. The onset of symptoms is gradual, and a history of trauma may be elicited. The patient frequently complains of a dull, aching pain that is often associated with stiffness. Occasionally, episodes of locking occur if the fragment has become extruded into the joint. The physical findings consist of limitation of motion, local tenderness, and joint effusion. Roentgenographically, the capitellum is the most common site of involvement (Fig. 6-8).

Fig. 6-8 Osteochondritis dissecans of the elbow. Sclerosis, rarefaction, and a small loose body are present (arrow).

TREATMENT

The treatment in early cases consists of rest. This may require the use of a sling. All throwing activities are discontinued. Surgery is indicated for removal of any loose bodies. The prognosis is usually good in patients younger than 10 years of age (Panner’s disease). When the condition develops later, some residual stiffness may occur, and late osteoarthritis may even develop.

Pronator Syndrome

The median nerve gives off its motor branch, the anterior interosseous nerve, below the elbow as it passes between the two heads of the pronator teres muscle just behind the biceps aponeurosis. An uncommon form of compression neuropathy can occur at this site, which is called pronator syndrome. Entrapment can also cause a very specific clinical presentation, sometimes referred to as the anterior interosseous nerve syndrome if only the motor branch is affected. The etiology is usually some form of localized anatomic compression, but the disorder can follow injury or even a traumatic phlebotomy.

Clinical features include forearm discomfort and fatigue, often resulting from repetitive pronation. The onset is insidious, and nocturnal paresthesias are not typical, in contrast to carpal tunnel syndrome. Vague hand numbness in the median nerve distribution may be present, but sensory changes usually do not develop if only the motor branch is involved.

If only the anterior interosseous branch is affected, sensation to the hand is normal. Forearm pain and weakness may develop, and if sufficient compression has occurred, weakness of the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) to the index finger may be present. The patient may then be unable to form a circle when trying to pinch the index and thumb because of inability to flex the distal phalanges of those fingers (Fig. 6-9).

Fig. 6-9 Pinch-grip test. The patient cannot form a circle because of weakness of the index FDP and the FPL. Instead, there is pulp to pulp contact. This is usually a late finding.

Electrodiagnostic studies may be helpful, although results of such studies are often normal. Plain radiographs should be obtained to rule out bony abnormalities that could cause compression.

Treatment is directed toward identifying and eliminating any known causative factors. Rest, stretching exercises, and NSAIDS may be helpful. Surgical referral is indicated in cases of failed medical management or when motor weakness is present.

NOTE: This condition is often difficult to diagnose. Sometimes, the anatomic site of compression can only be determined at the time of surgery when all potential sites are explored and decompressed.

Pulled Elbow

Pulled elbow, or “nursemaid’s elbow,” is a disorder in which the head of the radius becomes subluxed beneath the orbicular ligament (Fig. 6-10). This occurs as a result of longitudinal traction on the hand with the elbow extended and the forearm in a pronated position. A common situation in which this occurs is when a child is lifted up by the wrist or hand.

Fig. 6-10 The radial head is pulled beneath the orbicular ligament.

CLINICAL FEATURES

Pulled elbow is most common between the ages of 1 and 3 years and is rare after the age of 6. Clinically, an audible snap may be heard when the radial head subluxes. The arm is then held motionless at the side in slight flexion and pronation. The radial head is tender. Roentgenographic findings are usually normal, presumably because the subluxation has spontaneously reduced or because reduction occurred in the process of radiographic positioning. Rarely, an abnormality may be visualized (Fig. 6-11).

Fig. 6-11 Lateral radiograph of the elbow showing subluxation of the radial head. The line of the radius no longer passes through the capitellum (C).

TREATMENT

Reduction is easily accomplished by supinating and flexing the forearm while applying manual pressure over the radial head (Fig. 6-12). A palpable click can be noted as reduction occurs, and the pain is immediately relieved. Reduction sometimes occurs in the radiology department when the technician places the forearm and the elbow in the flexed and supinated position to obtain a lateral view of the elbow. After reduction, a sling is worn for 5 to 7 days, if needed. Recurrences occasionally take place and are treated in a similar manner.

Fig. 6-12 Reduction of a “pulled elbow.”

Olecranon Bursitis

The olecranon bursa overlies the olecranon process and is extremely vulnerable to direct trauma and repeated irritation. It may also be involved in gout and rheumatoid arthritis. After an acute traumatic episode, usually a contusion, a tender, painful swelling may develop over the tip of the olecranon. Elbow motion is usually normal. The bursa sac fills with blood or clear fluid. At this stage, aspiration (with culture if fluid is suspicious for infection) of the fluid with application of a compression dressing and ice may prevent reformation of the fluid and recurrence. Many acute lesions will spontaneously subside, however. Roentgenograms should be obtained to rule out fracture of the olecranon if trauma is involved.

With repetitive trauma, a chronic inflammatory reaction may occur that results in the formation of a thickened, rubbery bursa (Fig. 6-13). This bursa is usually not painful, in contrast to the swelling that occurs after an acute injury. Palpation may reveal multiple, small, hard nodules that feel like loose bodies. These usually are not chips of bone but instead represent villous thickenings or tissue debris in the bursa. Aspiration of the bursa may be attempted, but the fluid often recurs. Resolution may be improved by intrabursal injection of 1 mL of steroid (Fig. 6-14). Incision is not recommended because a chronic draining sinus infection often results. If the bursa is chronically painful, excision is recommended. Usually, the bursa will “dry up” eventually on its own, however. Elbow pads or other forms of protection may be helpful.

Fig. 6-13 Chronic olecranon bursitis (arrow).

Fig. 6-14 Olecranon bursa aspiration. The needle site should be infiltrated first with local anesthetic because an 18-gauge needle will be used. As much fluid is removed as possible. This can be increased by digitally expressing the fluid to the site of the needle; 1 mL of steroid can be injected if there is no indication of infection.

Occasionally, the bursa is the site of an acute infection, usually staph, that sometimes follows trauma. The treatment is the same as that for any other infection and consists of antibiotics, moist heat, and splinting, with repeated aspirations or incision and drainage when necessary.

Distal Rupture of the Biceps Tendon

The distal end of the biceps tendon may rupture as the result of degenerative changes near its insertion into the radial tuberosity. The distal end of the biceps tendon undergoes the same attritional changes as those that occur in the long head at the shoulder. Sudden, forceful flexion of the elbow against resistance may then cause it to rupture at its insertion into the radius. A painful snap is felt at the elbow and is followed by swelling and tenderness. Flexion of the elbow and supination of the forearm are weakened. The overlying deep fascia of the antecubital fossa may remain intact, thus preventing a significant loss of elbow flexion power. On flexion of the elbow, the belly of the biceps retracts to produce a bulbous swelling in the upper arm similar to that seen with proximal rupture of the long head. Magnetic resonance imaging (MRI) is helpful in confirming the diagnosis and determining the extent of the injury.

Definitive treatment of the complete rupture is controversial. Surgical repair is often advised, depending on the demands of the patient. Tears of the muscular portion of the biceps are difficult to repair and are generally treated nonsurgically.

Dislocation of the Elbow

Dislocation of the elbow is a common injury and is usually posterior in direction (Fig. 6-15). It is generally the result of a fall on the outstretched hand with the elbow extended. Examination will reveal obvious deformity that must be differentiated from a supracondylar fracture. Avulsion fractures of the medial epicondyle and fractures of the radial head occasionally occur at the same time that may require surgical intervention. Reduction is performed as soon as possible. It can usually be accomplished by gentle, steady traction on the wrist with countertraction on the shoulder (Fig. 6-16). A general anesthetic is usually unnecessary. Extension of the elbow to unlock the olecranon may be necessary. After reduction, the elbow is tested for stability, and postreduction roentgenograms are always obtained. Lack of full motion following reduction suggests the possibility of an intraarticular fracture fragment. If the elbow is stable after reduction, it is rested in a sling for a few days. Gentle range-of-motion exercises are instituted as early as possible. Temporary stiffness is common, and full recovery of elbow motion may take several weeks. Motion should never be forced. The patient should be allowed to progress as tolerated. Forced passive motion only encourages more swelling, which leads to more stiffness. Some residual restriction of motion is not uncommon, but it is usually of such a minor degree that it does not interfere with function.

Fig. 6-15 Posterior dislocation of the elbow. A line drawn through the center of the radius no longer passes through the capitellum. A, AP view. B, Lateral view.

Fig. 6-16 A, Reduction of an elbow dislocation by straight traction. B, Parvin’s method. With the patient prone, gentle downward traction is applied to the wrist. A few minutes later, the arm is gently lifted upward, often reducing the dislocation.

Dislocation of the Radial Head in Children

This is a disorder that is usually traumatic but may occasionally be congenital or developmental in nature. Most traumatic cases dislocate anteriorly (Fig. 6-17). The mechanism of injury is usually a fall on the outstretched pronated arm, and the injury is frequently missed. Some cases may be associated with a “bent” ulna, suggesting a Monteggia type of injury. Congenital dislocations are usually posterior and are frequently bilateral. They may be associated with other congenital anomalies such as Ehlers–Danlos syndrome. Developmental dislocations are usually the result of cerebral palsy or neurologic injury and are commonly posterolateral. These two types of radial head dislocations usually have no pain and little functional impairment. No treatment is required unless symptoms are present.

Fig. 6-17 Anterior radial head dislocation. A, Lateral view showing subtle anterior dislocation. B, A more obvious dislocation. C, Anteroposterior view.

Traumatic dislocations, however, need early reduction to prevent stiffness and pain. Old neglected dislocations may benefit from surgery.

Recognition is important. Remember: a line drawn through the long axis of the radius should always pass through the capitellum in any view, and all articular surfaces should match together perfectly.

Fractures of the Elbow Region

FRACTURES OF THE HEAD AND NECK OF THE RADIUS

Fractures of the radial head and neck result from a fall on the outstretched hand with the elbow extended (Fig. 6-18). All are characterized by tenderness over the radial head, local swelling, and pain on rotation or flexion of the forearm.

Fig. 6-18 A, Various types of fractures of the radial head or neck that may be treated nonsurgically. B, Typical head fracture in which full, pain-free motion was restored following conservative treatment.

Undisplaced or minimally displaced fractures in adults and children are treated conservatively. If the swelling is extremely painful, the joint may be aspirated through the posterolateral triangle. A sling alone may be used, or a light posterior splint may be added with the elbow flexed 90 degrees. Protection beyond 7 to 10 days is usually not required, and early motion is encouraged. (Undisplaced radial head fractures are sometimes not easily visualized on initial roentgenograms. If there is a clinical suspicion of fracture, such as radial head tenderness and pain with rotation, treatment is indicated.) Full return of motion often takes several months. Large fragments may require open reduction with internal fixation.

Significantly comminuted fractures in adults are usually treated by early excision of the entire radial head. Otherwise, permanent restriction of joint motion and traumatic arthritis may result. Early removal is especially indicated in grossly comminuted and displaced fractures because the fracture fragments may act as a nidus for soft tissue calcification in the anterior elbow region, and myositis ossificans may result (Fig. 6-19). Open reduction may be considered in fractures with a single large displaced fragment.

Fig. 6-19 Roentgenogram of the elbow following a comminuted radial head fracture shows multiple areas of ossification (myositis ossificans) in the adjacent soft tissue (arrows).

Children’s fractures with less than 15 to 30 degrees of angulation are treated as undisplaced fractures with a long arm splint for 3 weeks. Displaced fractures, or fractures that are angulated greater than 15 to 30 degrees, are treated by closed or open reduction. However, the radial head is never removed in the growing child, because removal of the epiphysis will result in unequal growth of the forearm bones.

Regardless of the method of treatment, some mild loss of extension of the elbow is not uncommon. However, little functional impairment usually results.

FRACTURES OF THE OLECRANON

Fractures of the olecranon usually result from falls on the tip of the elbow (Fig. 6-20). They are either displaced or undisplaced. The extensor mechanism is intact in undisplaced fractures, and further displacement is unlikely. These fractures are easily treated with a posterior splint for 2 weeks, followed by a sling and gradually increasing range-of-motion exercises.

Fig. 6-20 Fracture of the olecranon with minimal displacement.

Displaced fractures usually require open reduction and internal fixation to restore the bony alignment and repair the triceps insertion.

Displaced fractures in the very elderly or debilitated are often treated with a sling and early motion. Function returns reasonably well in these patients, but some weakness is present, and if the patient needs the use of a walker, a functioning triceps is important. This might influence the decision regarding surgical repair.

THE SUPRACONDYLAR FRACTURE

This is the most common elbow fracture in children. The distal fragment is usually displaced posteriorly (Fig. 6-21). Neurologic and vascular injuries are not uncommon, but they usually only when the fracture is severely displaced.

FIG. 6-21 Supracondylar fracture of the humerus with minimal displacement.

Displaced fractures are considered an emergency. Reduction with pinning is performed as soon as possible, and the extremity is closely observed for neurovascular complications.

Undisplaced or minimally angulated fractures are treated with a posterior splint for 4 to 6 weeks.

FRACTURE OF THE LATERAL HUMERAL CONDYLE

This is a common fracture in children and is usually a Salter–Harris type IV injury. The fracture is sometimes missed because only a thin line of metaphyseal fragment may be visible, with the remainder of the fracture line crossing the cartilaginous trochlea (Fig. 6-22). It is a potentially serious injury because the fracture line passes through the growth plate and into the joint. Nonunion, malunion, and traumatic arthritis are potential complications.

FIG. 6-22 Fracture of the lateral condyle.

Undisplaced fracures are treated with a posterior splint for 5 weeks. Roentgenograms are repeated at 1 week to be certain that displacement has not occurred.

Displaced fractures usually need open reduction with pinning.

MONTEGGIA’S FRACTURE-DISLOCATION

This injury consists of a fracture of the proximal third of the ulna and a dislocation of the radial head (Fig. 6-23). Closed treatment may suffice in the child, but open reduction with internal fixation is frequently necessary in the adult.

Fig. 6-23 A, Monteggia’s fracture-dislocation of the elbow. Note the angulation of the ulna. Also, a line drawn through the shaft of the radius no longer passes through the capitellum. B, After reduction. Remember, it is always important to obtain a roentgenogram of the joint above and below any fracture.

Occasionally, especially in children, the fracture of the ulna may not be obvious, or the ulna fracture may be greenstick in nature and the radial head dislocation overlooked. Remember: always obtain roentgenograms of the joint above and below any fracture, especially if there is any shortening or angulation.