PEDIATRIC ELBOW

EPIDEMIOLOGY

Elbow fractures represent 8% to 9% of all upper extremity fractures in children.

Of all elbow fractures, 85% occur at the distal humerus; 55% to 75% of these are supracondylar.

Most occur in patients 5 to 10 years of age, more commonly in boys.

There is a seasonal distribution for elbow fractures in children, with the most occurring during the summer and the fewest during the winter.

ANATOMY

The elbow consists of three joints: the ulnohumeral, radiocapitellar, and proximal radioulnar.

The vascularity to the elbow is a broad anastomotic network that forms the intraosseous and extraosseous blood supplies.

• The capitellum is supplied by a posterior branch of the brachial artery that enters the lateral crista.

• The trochlea is supplied by a medial branch that enters along the nonarticular medial crista and

  a lateral branch that crosses the physis.

• There is no anastomotic connection between these two vessels.

The articulating surface of the capitellum and trochlea projects distally and anteriorly at an angle of approximately 30 to 45 degrees. The center of rotation of the articular surface of each condyle lies on the same horizontal axis; thus, malalignment of the relationships of the condyles to each other changes their arcs of rotation, limiting flexion and extension.

The carrying angle is influenced by the obliquity of the distal humeral physis; this averages 6 degrees in girls and 5 degrees in boys and is important in the assessment of angular growth disturbances.

In addition to anterior distal humeral angulation, there is horizontal rotation of the humeral

condyles in relation to the diaphysis, with the lateral condyle rotated 5 degrees medially. This medial rotation is often significantly increased with displaced supracondylar fractures.

The elbow accounts for only 20% of the longitudinal growth of the upper extremity.

Ossification: With the exception of the capitellum, ossification centers appear approximately 2 years earlier in girls compared with boys.

CRMTOL: The following is a mnemonic for the appearance of the ossification centers around the elbow (Fig. 44.1):

Capitellum: 6 months to 2 years; includes the lateral crista of the trochlea

Radial head: 4 years

Medial epicondyle: 6 to 7 years

Trochlea: 8 years

Olecranon: 8 to 10 years; often multiple centers, which ultimately fuse

Lateral epicondyle: 12 years

MECHANISM OF INJURY

Indirect: This is most commonly a result of a fall onto an outstretched upper extremity.

Direct: Direct trauma to the elbow may occur from a fall onto a flexed elbow or from an object striking the elbow (e.g., baseball bat, automobile).

CLINICAL EVALUATION

Patients typically present with varying degrees of gross deformity, usually accompanied by pain, swelling, tenderness, irritability, and refusal to use the injured extremity.

The ipsilateral shoulder, humeral shaft, forearm, wrist, and hand should be examined for associated injuries.

A careful neurovascular examination should be performed, with documentation of the integrity of the median, radial, and ulnar nerves, as well as distal pulses and capillary refill. Flexion of the elbow in the presence of antecubital swelling may cause neurovascular compromise; repeat evaluation of neurovascular integrity is essential following any manipulation or treatment.

All aspects of the elbow should be examined for possible open lesions; clinical suspicion may be followed with intra-articular injection of saline into the elbow to evaluate possible intra-articular communication of a laceration.

RADIOGRAPHIC EVALUATION

Standard anteroposterior (AP) and lateral views of the elbow should be obtained. On the AP view, the following angular relationships may be determined (Fig. 44.2):

• Baumann angle: This is the angulation of the lateral condylar physeal line with respect to the long axis of the humerus; normal is 11 to 20 degrees but should be compared to opposite side.

• Humeral-ulnar angle: This angle is subtended by the intersection of the diaphyseal bisectors of

  the humerus and ulna; this best reflects the true carrying angle. Normal is 5 to 15 degrees.

• Metaphyseal–diaphyseal angle: This angle is formed by a bisector of the humeral shaft with respect to a line delineated by the widest points of the distal humeral metaphysis. Normal is 34 to 42 degrees.

   

   

   

On a true lateral radiograph of the elbow flexed to 90 degrees, the following landmarks should be observed (Fig. 44.3):

• Teardrop: This radiographic shadow is formed by the posterior margin of the coronoid fossa anteriorly, the anterior margin of the olecranon fossa posteriorly, and the superior margin of the capitellar ossification center inferiorly.

• Diaphyseal–condylar angle: This projects 30 to 45 degrees anteriorly; the posterior capitellar physis is typically wider than the anterior physis.

• Anterior humeral line: When extended distally, this line should intersect the middle third of the

  capitellar ossification center.

• Coronoid line: A proximally directed line along the anterior border of the coronoid process should be tangent to the anterior aspect of the lateral condyle.

   

   

   

A line drawn through the center of the capitellum should bisect the radial head.

Special views

• Jones view: Pain may limit an AP radiograph of the elbow in extension; in these cases, a radiograph may be taken with the elbow hyperflexed and the beam directed at the elbow through the overlying forearm with the arm flat on the cassette in neutral rotation.

• Internal and external rotation views (column views) may be obtained in cases in which a fracture is suspected but not clearly demonstrated on routine views. These may be particularly useful in the identification of coronoid process or radial head fractures.

Radiographs of the contralateral elbow should be obtained for comparison and identification of ossification centers. A pseudofracture of an ossification center may exist, in which apparent fragmentation of an ossification center may represent a developmental variant rather than a true fracture. This may be clarified with comparison views of the uninjured contralateral elbow.

Fat pad signs: Three fat pads overlie the major structures of the elbow (Fig. 44.4):

• Anterior (coronoid) fat pad: This triangular lucency seen anterior to the distal humerus may represent displacement of the fat pad owing to underlying joint effusion. The coronoid fossa is shallow; therefore, anterior displacement of the fat pad is sensitive to small effusions. However,

  an exuberant fat pad may be seen without associated trauma, diminishing the specificity of the anterior fat pad sign.

• Posterior (olecranon) fat pad: The deep olecranon fossa normally contains the entire posterior fat pad. Thus, only moderate to large effusions cause posterior displacement, resulting in a high specificity of the posterior fat pad sign for intra-articular disorders (a fracture is present >70% of the time when the posterior fat pad is seen).

• Supinator fat pad: This represents a layer of fat on the anterior aspect of the supinator muscle as it wraps around the proximal radius. Anterior displacement of this fat pad may represent a fracture of the radial neck; however, this sign has been reported to be positive in only 50% of cases.

• Anterior and posterior fat pads may not be seen following elbow dislocation owing to disruption of the joint capsule, which decompresses the joint effusion.

   

   

  SPECIFIC FRACTURES

  Supracondylar Humerus Fractures

  Epidemiology

These comprise 55% to 75% of all elbow fractures.

The male-to-female ratio is 3:2.

The peak incidence is from 5 to 8 years, after which dislocations become more frequent.

The nondominant side is most frequently injured.

Anatomy

Remodeling of bone in the 5- to 8-year-old causes a decreased AP diameter in the supracondylar region, making this area susceptible to injury.

Ligamentous laxity in this age range increases the likelihood of hyperextension injury.

The anterior capsule is thicker and stronger than the posterior capsule. In extension, the fibers of the anterior capsule are taut, serving as a fulcrum by which the olecranon becomes firmly engaged

in the olecranon fossa. With extreme force, hyperextension may cause the olecranon process to impinge on the superior olecranon fossa and supracondylar region.

The periosteal hinge remains intact on the side of the displacement.

Mechanism of Injury

Extension type: Hyperextension occurs during fall onto an outstretched hand with or without varus/valgus force. If the hand is pronated, posteromedial displacement occurs. If the hand is supinated, posterolateral displacement occurs. Posteromedial displacement is more common.

Flexion type: The cause is direct trauma or a fall onto a flexed elbow.

Clinical Evaluation

Patients typically present with a swollen, tender elbow with painful range of motion.

S-shaped angulation at the elbow: A complete (type III) fracture results in two points of angulation to give it an S shape.

Pucker sign: This is dimpling of the skin anteriorly secondary to penetration of the proximal fragment into the brachialis muscle; it should alert the examiner that reduction of the fracture may be difficult with simple manipulation.

Neurovascular examination: A careful neurovascular examination should be performed with documentation of the integrity of the median, radial, and ulnar nerves as well as their terminal branches. Capillary refill and distal pulses as well as warmth of the hand should be documented. The examination should be repeated following splinting or manipulation.

Classification.

Extension Type

This represents 98% of supracondylar humerus fractures in children.

Gartland

This is based on the degree of displacement.

Type I: Nondisplaced

Type II: Displaced with intact posterior cortex; may be angulated or rotated

Type III: Complete displacement; posteromedial or posterolateral

Flexion Type

This comprises 2% of supracondylar humerus fractures in children.

Gartland

Type I: Nondisplaced

Type II: Displaced with intact anterior cortex

Type III: Complete displacement; usually anterolateral

Treatment

Extension Type

Type I: Immobilization in a long arm cast or splint at 60 to 90 degrees of flexion is indicated for 2 to 3 weeks.

Type II: This is usually reducible by closed methods followed by casting; it may require pinning if unstable (crossed pins versus two lateral pins) or if reduction cannot be maintained without excessive flexion and risk of damage to neurovascular structures.

Type III: Attempt closed reduction and pinning; traction (olecranon skeletal traction) may be needed for comminuted fractures with marked soft tissue swelling or damage.

Open reduction and internal fixation may be necessary for rotationally unstable fractures, open fractures, and those with neurovascular injury (crossed pins versus two lateral pins).

Concepts involved in reduction

• Displacement is corrected in the coronal and horizontal planes before the sagittal plane.

• Hyperextension of the elbow with longitudinal traction is used to obtain apposition; this maneuver is only occasionally required.

• Flexion of the elbow is done while applying a posterior force to the distal fragment (thumb is

  placed on the olecranon while flexing the elbow).

• Stabilization with control of displacement in the coronal, sagittal, and horizontal planes is recommended.

• Lateral pins are placed first to obtain provisional stabilization, and if a medial pin is needed,

  the elbow can be extended before pin placement to help protect the ulnar nerve.

  Flexion Type

  Type I: Immobilization in a long arm cast in near extension is indicated for 2 to 3 weeks.

  Type II: Closed reduction is followed by percutaneous pinning with two lateral pins or crossed pins.

  Type III: Reduction is often difficult; most require open reduction and internal fixation with crossed pins.

Immobilization in a long arm cast (or posterior splint if swelling is an issue) with the elbow flexed less than 90 degrees, depending on the extent of the swelling, and the forearm in neutral should be undertaken for 3 weeks postoperatively, at which time the cast may be discontinued and the pins removed. The patient should then be maintained in a sling when in danger of falling and given active range-of-motion exercises. Sports activity should be restricted for an additional 3 weeks.

Complications

Neurologic injury (7% to 10%): This may be caused by a traction injury at the time of the fracture or very rarely at the time of reduction. The neurovascular structures may be tented or entrapped in the fracture site. Neurologic injury is also a component of Volkmann ischemic contracture. Most injuries seen from supracondylar humerus fractures are neurapraxias, requiring no treatment.

• Median nerve/anterior interosseous nerve (most common)

• Radial nerve

• Ulnar nerve: This is most common in flexion-type supracondylar fractures; early injury may result from tenting over the medial spike of the proximal fragment; late injury may represent progressive valgus deformity of the elbow. It is frequently iatrogenic in extension-type supracondylar fractures following medial pinning.

Vascular injury (0.5%): This may represent direct injury to the brachial artery or may be secondary to antecubital swelling. This emphasizes the need for a careful neurovascular examination both on initial presentation and following manipulation or splinting, especially after elbow flexion is performed. Observation is warranted if the pulse is absent, yet the hand is still well perfused and warm.

Loss of motion: A >5 degree loss of elbow motion occurs in 5% secondary to poor reduction or soft tissue contracture.

Myositis ossificans: Rare and is seen after vigorous manipulation.

Angular deformity (varus more frequently than valgus): Significant in 10% to 20%; the occurrence is decreased with percutaneous pinning (3%) compared with reduction and casting alone (14%).

Compartment syndrome (<1%): This rare complication can be exacerbated by elbow hyperflexion when excessive swelling is present in the cubital fossa.

Lateral Condylar Physeal Fractures

Epidemiology

These comprise 17% of all distal humerus fractures.

Peak age is 6 years.

Often result in less satisfactory outcomes than supracondylar fractures because:

• Diagnosis less obvious and may be missed in subtle cases.

• Loss of motion is more severe due to intra-articular nature.

• The incidence of growth disturbance is higher.

  Anatomy

The ossification center of the lateral condyle extends to the lateral crista of the trochlea.

Lateral condylar physeal fractures are typically accompanied by a soft tissue disruption between the origins of the extensor carpi radialis longus and the brachioradialis muscles; these origins remain attached to the free distal fragment, accounting for initial and late displacement of the fracture.

Disruption of the lateral crista of the trochlea (Milch type II fractures) results in posterolateral subluxation of the proximal radius and ulna with consequent cubitus valgus; severe posterolateral translocation may lead to the erroneous diagnosis of primary elbow dislocation.

Mechanism of Injury

“Pull-off” theory: Avulsion injury occurs by the common extensor origin owing to a varus stress exerted on the extended elbow.

“Push-off” theory: A fall onto an extended upper extremity results in axial load transmitted through the forearm, causing the radial head to impinge on the lateral condyle.

Clinical Evaluation

Unlike the patient with a supracondylar fracture of the elbow, patients with lateral condylar fractures typically present with little gross distortion of the elbow, other than mild swelling from fracture hematoma most prominent over the lateral aspect of the distal humerus.

Crepitus may be elicited upon supination–pronation motions of the elbow.

Pain, swelling, tenderness to palpation, painful range of motion, and pain on resisted wrist extension may be observed.

Radiographic Evaluation

AP, lateral, and oblique views of the elbow should be obtained.

Varus stress views may accentuate displacement of the fracture.

In a young child whose lateral condyle is not ossified, it may be difficult to distinguish between a lateral condylar physeal fracture and a complete distal humeral physeal fracture. In such cases, an arthrogram may be helpful, and the relationship of the lateral condyle to the proximal radius is critical.

• Lateral condyle physeal fracture: This disrupts the normal relationship with displacement of the proximal radius laterally owing to loss of stability provided by the lateral crista of the distal humerus.

• Fracture of the entire distal humeral physis: The relationship of the lateral condyle to the proximal radius is intact, often accompanied by posteromedial displacement of the proximal radius and ulna.

Magnetic resonance imaging (MRI) may help in order to appreciate the direction of the fracture line and the pattern of fracture.

Classification

Milch (Fig. 44.5)

Type I: The fracture line courses lateral to the trochlea and into the capitellar–trochlear groove. It represents a Salter-Harris type IV fracture: the elbow is stable because the trochlea is intact; this is less common.

Type II: The fracture line extends into the apex of the trochlea. It represents a Salter-Harris type II fracture: the elbow is unstable because the trochlea is disrupted; this is more common (Fig. 44.5).

Treatment

Nonoperative

Nondisplaced or minimally displaced fractures (Jakob stage I; <2 mm) (40% of fractures) may be treated with simple immobilization in a posterior splint or long arm cast with the forearm in neutral position and the elbow flexed to 90 degrees. This is maintained for 3 to 6 weeks until there is healing of the fracture, after which range-of-motion exercises are instituted.

Closed reduction with a varus force as well as supination and extension may be attempted in Jakob type II fractures. If articular reduction is achieved, it should be held with percutaneous wires in order to prevent displacement. An arthrogram can be performed to ensure a reduction was achieved.

Operative

Open reduction is required for unstable Jakob stage II and stage III fractures (60%).

• The fragment may be secured with two crossed, smooth Kirschner wires that diverge in the metaphysis.

• The passage of smooth pins through the physis does not typically result in growth disturbance.

• Care must be taken when dissecting near the posterior aspect of the lateral condylar fragment because the sole vascular supply is provided through soft tissues in this region.

• Postoperatively, the elbow is maintained in a long arm cast at 60 to 90 degrees of flexion with

  the forearm in neutral rotation. The cast is discontinued 3 to 6 weeks postoperatively with pin removal. Active range-of-motion exercises are instituted.

If treatment is delayed (>3 to 6 weeks), closed treatment should be strongly considered, regardless of displacement, owing to the high incidence of osteonecrosis of the condylar fragment and significant joint stiffness with late open reduction.

Complications

Lateral condylar overgrowth with spur formation: This usually results from an ossified periosteal flap raised from the distal fragment at the time of injury or surgery. It may represent a cosmetic problem (cubitus pseudovarus) as the elbow gains the appearance of varus owing to a lateral prominence but is generally not a functional problem.

Delayed union or nonunion (>12 weeks): This is caused by pull of extensors and poor metaphyseal circulation of the lateral condylar fragment, most commonly in patients treated nonoperatively. It may result in cubitus valgus necessitating ulnar nerve transposition for tardy ulnar nerve palsy. Treatment ranges from benign neglect to osteotomy and compressive fixation late or at skeletal maturity.

Angular deformity: Cubitus valgus occurs more frequently than varus owing to lateral physeal arrest. Tardy ulnar nerve palsy may develop necessitating transposition.

Neurologic compromise: This is rare in the acute setting. Tardy ulnar nerve palsy may develop as a result of cubitus valgus.

Osteonecrosis: This may be iatrogenic, especially when surgical intervention was delayed. It may result in a “fishtail” deformity with a persistent gap between the lateral physeal ossification center and the medial ossification of the trochlea. Osteonecrosis does not appear to have long-term clinical sequelae.

Medial Condylar Physeal Fractures

Epidemiology

Represent <1% of distal humerus fractures.

Typical age range is 8 to 14 years.

Anatomy

Medial condylar fractures are Salter-Harris type IV fractures with an intra-articular component involving the trochlea and an extra-articular component involving the medial metaphysis and the medial epicondyle (common flexor origin).

Only the medial crista is ossified by the secondary ossification centers of the medial condylar epiphysis.

The vascular supply to the medial epicondyle and metaphysis is derived from the flexor muscle group. The vascular supply to the lateral aspect of the medial crista of the trochlea traverses the surface of the medial condylar physis, rendering it vulnerable in medial physeal disruptions with possible avascular complications and “fishtail” deformity.

Mechanism of Injury

Direct: Trauma to the olecranon, such as a fall onto a flexed elbow, results in the semilunar notch of the olecranon traumatically impinging on the trochlea, splitting it with the fracture line extending proximally to metaphyseal region.

Indirect: A fall onto an outstretched hand with valgus strain on the elbow results in an avulsion injury with the fracture line starting in the metaphysis and propagating distally through the articular surface.

These are considered the mirror image of lateral condylar physeal fractures.

Once dissociated from the elbow, the powerful forearm flexor muscles produce sagittal anterior rotation of the fragment.

Clinical Evaluation

Patients typically present with pain, swelling, and tenderness to palpation over the medial aspect of the distal humerus. Range of motion is painful, especially with resisted flexion of the wrist.

A careful neurovascular examination is important because ulnar nerve symptoms may be present.

A common mistake is to diagnose a medial condylar physeal fracture erroneously as an isolated medial epicondylar fracture. This occurs based on tenderness and swelling medially in conjunction with radiographs demonstrating a medial epicondylar fracture only resulting from the absence of a medial condylar ossification center in younger patients.

Medial epicondylar fractures are often associated with elbow dislocations, usually posterolateral; elbow dislocations are extremely rare before ossification of the medial condylar epiphysis begins. With medial condylar physeal fractures, subluxation of the elbow posteromedially is often observed. A positive fat pad sign indicates an intra-articular fracture, whereas a medial epicondyle fracture is typically extra-articular with no fat pad sign seen on radiographs.

Radiographic Evaluation

AP, lateral, and oblique views of the elbow should be obtained.

In young children whose medial condylar ossification center is not yet present, radiographs may demonstrate a fracture in the epicondylar region; in such cases, an arthrogram may delineate the course of the fracture through the articular surface, indicating a medial condylar physeal fracture.

Stress views may help to distinguish epicondylar fractures (valgus laxity) from condylar fractures (both varus and valgus laxity).

MRI may help to appreciate the direction of the fracture line and the pattern of fracture.

Classification

Milch (Fig. 44.6)

Type I: Fracture line traversing through the apex of the trochlea: Salter-Harris type II; more common presentation

Type II: Fracture line through capitulotrochlear groove: Salter-Harris type IV; infrequent presentation

Kilfoyle

Stage I: Nondisplaced, articular surface intact

Stage II: Fracture line complete with minimal displacement

Stage III: Complete displacement with rotation of fragment from pull of flexor mass

Treatment

Nonoperative

Nondisplaced or minimally displaced fractures (Kilfoyle stage I) may be treated with immobilization in a long arm cast or posterior splint with the forearm in neutral rotation and the elbow flexed to 90 degrees for 3 to 4 weeks, followed by range-of-motion and strengthening exercises.

Closed reduction may be performed with the elbow extended and the forearm pronated to relieve tension on the flexor origin, with placement of a posterior splint or long arm cast. Unstable reductions require percutaneous pinning with two parallel metaphyseal pins.

Closed reduction is often difficult because of medial soft tissue swelling.

Open reduction is usually required for stages II and III fractures.

Operative

Irreducible or unstable Kilfoyle stage II or stage III fractures of the medial condylar physis require open reduction and internal fixation. Rotation of the condylar fragment may preclude successful closed treatment.

• A medial approach may be used with identification and protection of the ulnar nerve.

• The posterior surface of the condylar fragment and the medial aspect of the medial crista of the trochlea should be avoided in the dissection because these provide the vascular supply to the trochlea.

• Smooth Kirschner wires placed in a parallel configuration extending to the metaphysis may be used for fixation, or cancellous screw fixation may be used in adolescents near skeletal maturity.

• Postoperative immobilization consists of long arm casting with the forearm in neutral rotation and the elbow flexed to 90 degrees for 3 to 4 weeks, at which time the pins and the cast may be discontinued and active range-of-motion exercises instituted.

If treatment is delayed (>3 to 6 weeks), closed treatment should be strongly considered, regardless of displacement, owing to the high incidence of osteonecrosis of the trochlea and significant joint stiffness from extensive dissection with late open reduction.

Complications

Missed diagnosis: The most common is a medial epicondylar fracture owing to the absence of ossification of the medial condylar ossification center. Late diagnosis of medial condylar physeal fracture should be treated nonoperatively.

Nonunion: Uncommon and usually represent untreated, displaced medial condylar physeal

fractures secondary to pull of flexors with rotation. They tend to demonstrate varus deformity. After ossification, the lateral edge of the fragment may be observed to extend to the capitulotrochlear groove.

Angular deformity: Untreated or treated medial condylar physeal fractures may demonstrate angular deformity, usually varus, either secondary to angular displacement or from medial physeal arrest. Cubitus valgus may result from overgrowth of the medial condyle.

Osteonecrosis: This may result after open reduction and internal fixation, especially when extensive dissection is undertaken.

Ulnar neuropathy: This may be early, related to trauma, or more commonly, late, related to the development of angular deformities or scarring. Recalcitrant symptoms may be addressed with ulnar nerve transposition.

Transphyseal Fractures

Epidemiology

Most occur in patients younger than ages 6 to 7 years.

These were originally thought to be extremely rare injuries. It now appears that with advanced imaging (e.g., MRI), they occur fairly frequently, although the exact incidence is not known owing to misdiagnoses.

Anatomy

The epiphysis includes the medial epicondyle until ages 6 to 7 years in girls and ages 8 to 9 years in boys, at which time ossification occurs. Fractures before this time thus include medial epicondyle.

The younger the child, the greater the volume of the distal humerus that is occupied by the distal epiphysis; as the child matures, the physeal line progresses distally, with a V-shaped cleft forming between the medial and lateral condylar physes—this cleft protects the distal humeral epiphysis from fracture in the mature child, because fracture lines tend to exit through the cleft.

The joint surface is not involved in this injury, and the relationship between the radius and capitellum is maintained.

The AP diameter of the bone in this region is wider than in the supracondylar region, and consequently, there is not as much tilting or rotation.

The vascular supply to the medial crista of the trochlea courses directly through the physis; in cases of fracture, this may lead to avascular changes.

The physeal line is in a more proximal location in younger patients; therefore, hyperextension injuries to the elbow tend to result in physeal separations instead of supracondylar fractures through bone.

Mechanism of Injury

Birth injuries: Rotatory forces coupled with hyperextension injury to the elbow during delivery may result in traumatic distal humeral physeal separation.

Child abuse: In young children, child abuse must be suspected, because a high incidence of transphyseal fracture is associated with abuse.

Trauma: This may result from hyperextension injuries with posterior displacement, coupled with a rotation moment.

Clinical Evaluation

Young infants or newborns may present with pseudoparalysis of the affected extremity, minimal swelling, and “muffled crepitus,” because the fracture involves softer cartilage rather than firm, osseous tissue.

Older children may present with pronounced swelling, refusal to use the affected extremity, and pain that precludes a useful clinical examination or palpation of bony landmarks. In general, because of the large, wide fracture surface, there is less tendency for tilting or rotation of the distal fragment, resulting in less deformity than seen in supracondylar fractures. The bony relationship between the humeral epicondyles and the olecranon is maintained.

A careful neurovascular examination should be performed, because swelling in the cubital fossa may result in neurovascular compromise.

Radiographic Evaluation

AP, lateral, and oblique radiographs should be obtained.

The proximal radius and ulna maintain normal anatomic relationships to each other, but they are displaced posteromedially with respect to the distal humerus. This is considered diagnostic of transphyseal fracture.

Comparison views of the contralateral elbow may be used to identify posteromedial displacement.

In the child whose lateral condylar epiphysis is ossified, the diagnosis is much more obvious. There is maintenance of the lateral condylar epiphysis to radial head relationship and posteromedial displacement of the distal humeral epiphysis with respect to the humeral shaft.

Transphyseal fractures with large metaphyseal components may be mistaken for a low supracondylar fracture or a fracture of the lateral condylar physis. These may be differentiated by the presence of a smooth outline of the distal metaphysis in fractures involving the entire distal physis as compared with the irregular border of the distal aspect of the distal fragment seen in supracondylar fractures.

Elbow dislocations in children are rare, but they may be differentiated from transphyseal fractures by primarily posterolateral displacement and a disrupted relationship between the lateral condylar epiphysis and the proximal radius.

An arthrogram may be useful for clarification of the fracture pattern and differentiation from an intra-articular fracture.

MRI may be helpful in appreciating the direction of the fracture line and the pattern of fracture.

Ultrasound may be useful in evaluating neonates and infants in whom ossification has not yet begun.

Classification

DeLee

This is based on ossification of the lateral condyle.

Group A: Infant, before the appearance of the lateral condylar ossification center (birth to 7 months); diagnosis easily missed; Salter-Harris type I

Group B: Lateral condyle ossified (7 months to 3 years); Salter-Harris type I or II (fleck of metaphysis)

Group C: Large metaphyseal fragment, usually exiting laterally (ages 3 to 7 years)

Treatment

Because many of these injuries in infants and toddlers represent child abuse injuries, it is not uncommon for parents to delay seeking treatment.

Nonoperative

Closed reduction with immobilization is performed with the forearm pronated and the elbow in 90 degrees of flexion if the injury is recognized early (within 4 to 5 days). This is maintained for 3 weeks, at which time the patient is allowed to resume active range of motion.

When treatment is delayed beyond 6 to 7 days of injury, the fracture should not be manipulated regardless of displacement, because the epiphyseal fragment is no longer mobile and other injuries may be precipitated; rather, splinting for comfort should be undertaken. Most fractures completely remodel by maturity.

Operative

DeLee type C fracture patterns or unstable injuries necessitate percutaneous pinning for fixation. An arthrogram is usually performed to determine the adequacy of reduction.

Angulation and rotational deformities that cannot be reduced by closed methods may require open reduction and internal fixation with pinning for fixation.

Postoperatively, the patient may be immobilized with the forearm in pronation and the elbow flexed to 90 degrees. The pins and cast are discontinued at 3 weeks, at which time active range of motion is permitted.

Complications

Malunion: Cubitus varus is most common, although the incidence is lower than with supracondylar fractures of the humerus because of the wider fracture surface of transphyseal fractures that do not allow as much angulation compared with supracondylar fractures.

Neurovascular injury: Extremely rare because the fracture surfaces are covered with cartilage. Closed reduction and immobilization should be followed by repeat neurovascular assessment, given that swelling in the antecubital fossa may result in neurovascular compromise.

Nonunion: Extremely rare because the vascular supply to this region is good.

Osteonecrosis: May be related to severe displacement of the distal fragment or iatrogenic injury, especially with late exploration.

Medial Epicondylar Apophyseal Fractures

Epidemiology

These comprise 11%–20% of distal humerus fractures.

Of these fractures, 60% are associated with elbow dislocations.

The peak age is 11 to 12 years.

The male-to-female ratio is 4:1.

Anatomy

The medial epicondyle is a traction apophysis for the medial collateral ligament and wrist flexors. It does not contribute to humeral length. The forces across this physis are tensile rather than compressive.

Ossification begins at 4 to 6 years of age; it is the last ossification center to fuse with the metaphysis (15 years) and does so independently of the other ossification centers.

The fragment is usually displaced distally and may be incarcerated in the joint 15% to 18% of the time.

It is often associated with fractures of the proximal radius, olecranon, and coronoid.

In younger children, a medial epicondylar apophyseal fracture may have an intracapsular component, because the elbow capsule may attach as proximally as the physeal line of the epicondyle. In the older child, these fractures are generally extracapsular given that the capsular attachment is more distal to the medial crista of the trochlea.

Mechanism of Injury

Direct: Trauma to the posterior or posteromedial aspect of the medial epicondyle may result in fracture, although these are rare and tend to produce fragmentation of the medial epicondylar fragment.

Indirect:

• Secondary to elbow dislocation: The ulnar collateral ligament provides avulsion force.

• Avulsion injury by flexor muscles results from valgus and extension force during a fall onto an outstretched hand or secondary to an isolated muscle avulsion from throwing a ball or arm wrestling, for example.

Chronic: Related to overuse injuries from repetitive throwing, as seen in skeletally immature baseball pitchers.

Clinical Evaluation

Patients typically present with pain, tenderness, and swelling medially.

Symptoms may be exacerbated by resisted wrist flexion.

A careful neurovascular examination is essential, because the injury occurs in proximity to the ulnar nerve, which can be injured during the index trauma or from swelling about the elbow.

Decreased range of motion is usually elicited and may be secondary to pain. Occasionally, a mechanical block to range of motion may result from incarceration of the epicondylar fragment

within the elbow joint.

Valgus instability can be appreciated on stress testing with the elbow flexed to 15 degrees to eliminate the stabilizing effect of the olecranon.

Radiographic Evaluation

AP, lateral, and oblique radiographs of the elbow should be obtained.

Because of the posteromedial location of the medial epicondylar apophysis, the ossification center may be difficult to visualize on the AP radiograph if it is even slightly oblique.

The medial epicondylar apophysis is frequently confused with fracture because of the occasionally fragmented appearance of the ossification center as well as the superimposition on the distal medial metaphysis. Better visualization may be obtained by a slight oblique of the lateral radiograph, which demonstrates the posteromedial location of the apophysis.

A gravity stress test may be performed, demonstrating medial opening on stress radiographs.

Complete absence of the apophysis on standard elbow views should prompt a search for the displaced fragment after comparison views of the contralateral, normal elbow are obtained. Specifically, incarceration within the joint must be sought, because the epicondylar fragment may be obscured by the distal humerus.

Fat pad signs are unreliable given that epicondylar fractures are extracapsular in older children and capsular rupture associated with elbow dislocation may compromise its ability to confine the hemarthrosis.

It is important to differentiate this fracture from a medial condylar physeal fracture; MRI or arthrogram may delineate the fracture pattern, especially when the medial condylar ossification center is not yet present.

Classification

Acute

• Nondisplaced

• Minimally displaced

• Significantly displaced (>5 mm) with a fragment proximal to the joint

• Incarcerated fragment within the olecranon–trochlea articulation

• Fracture through or fragmentation of the epicondylar apophysis, typically from direct trauma

Chronic

• Tension stress injuries (“Little League elbow”)

  Treatment

  Nonoperative

Most medial epicondylar fractures may be managed nonoperatively with immobilization. Studies demonstrate that although 60% may establish only fibrous union, 96% have good or excellent functional results.

Nonoperative treatment is indicated for nondisplaced or minimally displaced fractures and for

significantly displaced fractures in older or low-demand patients.

The patient is initially placed in a posterior splint with the elbow flexed to 90 degrees with the forearm in neutral or pronation.

The splint is discontinued 3 to 4 days after injury and early active range of motion is instituted. A sling is worn for comfort.

Aggressive physical therapy is generally not necessary unless the patient is unable to perform active range-of-motion exercises.

Operative

An absolute indication for operative intervention is an irreducible, incarcerated fragment within the elbow joint. Closed manipulation may be used to attempt to extract the incarcerated fragment from the joint as described by Roberts. The forearm is supinated, and valgus stress is applied to the elbow, followed by dorsiflexion of the wrist and fingers to put the flexors on stretch. This maneuver is successful approximately 40% of the time.

Relative indications for surgery include ulnar nerve dysfunction owing to scar or callus formation, valgus instability in an athlete, or significantly displaced fractures in younger or high-demand patients.

Acute fractures of the medial epicondyle may be approached through a longitudinal incision just anterior to the medial epicondyle. Ulnar nerve identification is important, but extensive dissection or transposition is generally unnecessary. After reduction and provisional fixation with Kirschner wires, fixation may be achieved with a lag-screw technique. A washer may be used in cases of poor bone stock or fragmentation.

Postoperatively, the patient is placed in a posterior splint or long arm cast with the elbow flexed to 90 degrees and the forearm pronated. This may be converted to a removable posterior splint or sling at 7 to 10 days postoperatively, at which time active range-of-motion exercises are instituted. Formal physical therapy is generally unnecessary if the patient is able to perform active exercises.

Complications

Unrecognized intra-articular incarceration: An incarcerated fragment tends to adhere and form a fibrous union to the coronoid process, resulting in significant loss of elbow range of motion. Although earlier recommendations were to manage this nonoperatively, recent recommendations are to explore the joint with excision of the fragment.

Ulnar nerve dysfunction: The incidence is 10% to 16%, although cases associated with fragment incarceration may have up to a 50% incidence of ulnar nerve dysfunction. Tardy ulnar neuritis may develop in cases involving reduction of the elbow or manipulation in which scar tissue may be exuberant. Surgical exploration and release may be warranted for symptomatic relief.

Nonunion: May occur in up to 60% of cases with significant displacement treated nonoperatively, although it rarely represents a functional problem.

Loss of extension: A 5% to 10% loss of extension is seen in up to 20% of cases, although this rarely represents a functional problem. This emphasizes the need for early active range-of-motion exercises.

Myositis ossificans: Rare, related to repeated and vigorous manipulation of the fracture. It may result in functional block to motion and must be differentiated from ectopic calcification of the collateral ligaments related to microtrauma, which does not result in functional limitation.

Lateral Epicondylar Apophyseal Fractures

Epidemiology

Extremely rare in children.

Anatomy

The lateral epicondylar ossification center appears at 10 to 11 years of age; however, ossification is not completed until the second decade of life.

The lateral epicondyle represents the origin of many of the wrist and forearm extensors; therefore, avulsion injuries account for a proportion of the fractures, as well as displacement once the fracture has occurred.

Mechanism of Injury

Direct trauma to the lateral epicondyle may result in fracture; these may be comminuted.

Indirect trauma may occur with forced volar flexion of an extended wrist, causing avulsion of the extensor origin, often with significant displacement as the fragment is pulled distally by the extensor musculature.

Clinical Evaluation

Patients typically present with lateral swelling and painful range of motion of the elbow and wrist, with tenderness to palpation of the lateral epicondyle.

Loss of extensor strength may be appreciated.

Radiographic Evaluation

The diagnosis is typically made on the AP radiograph, although a lateral view should be obtained to rule out associated injuries.

The lateral epicondylar physis represents a linear radiolucency on the lateral aspect of the distal humerus and is commonly mistaken for a fracture. Overlying soft tissue swelling, cortical discontinuity, and clinical examination should assist the examiner in the diagnosis of lateral epicondylar apophyseal injury.

Classification

Descriptive

Avulsion

Comminution

Displacement

Treatment

Nonoperative

With the exception of an incarcerated fragment within the joint, almost all lateral epicondylar apophyseal fractures may be treated with immobilization with the elbow in the flexed, supinated position until comfortable, usually by 2 to 3 weeks.

Operative

Incarcerated fragments within the elbow joint may be simply excised. Large fragments with associated tendinous origins may be reattached with screws or Kirschner wire fixation and postoperative immobilization for 2 to 3 weeks until comfortable.

Complications

Nonunion: Commonly occurs with established fibrous union of the lateral epicondylar fragment, although it rarely represents a functional or symptomatic problem.

Incarcerated fragments: May result in limited range of motion, most commonly in the radiocapitellar articulation, although free fragments may migrate to the olecranon fossa and limit terminal extension.

Capite lum Fractures

Epidemiology

Of these fractures, 31% are associated with injuries to the proximal radius.

Rare in children, representing 1:2,000 fractures about the elbow.

No verified, isolated fractures of the capitellum have ever been described in children younger than 12 years of age.

Anatomy

The fracture fragment is composed mainly of pure articular surface from the capitellum and essentially nonossified cartilage from the secondary ossification center of the lateral condyle.

Mechanism of Injury

Indirect force from axial load transmission from the hand through the radial head causes the radial head to strike the capitellum.

The presence of recurvatum or cubitus valgus predisposes the elbow to this fracture pattern.

Clinical Evaluation

Patients typically present with minimal swelling with painful range of motion. Flexion is often limited by the fragment.

Valgus stress tends to reproduce the pain over the lateral aspect of the elbow.

Supination and pronation may accentuate the pain.

Radiographic Evaluation

AP and lateral views of the elbow should be obtained.

Radiographs of the normal, contralateral elbow may be obtained for comparison.

If the fragment is large and encompasses ossified portions of the capitellum, it is most readily appreciated on the lateral radiograph.

Oblique views of the elbow may be obtained if radiographic abnormality is not appreciated on standard AP and lateral views, especially because a small fragment may be obscured by the density of the overlying distal metaphysis on the AP view.

Arthrography or MRI may be helpful when a fracture is not apparent but is suspected to involve purely cartilaginous portions of the capitellum.

Classification

Type I: Hahn–Steinthal fragment: Large osseous component of capitellum, often involving the lateral crista of the trochlea

Type II: Kocher–Lorenz fragment: Articular cartilage with minimal subchondral bone attached; “uncapping of the condyle”

Treatment

Nonoperative

Nondisplaced or minimally displaced fractures may be treated with casting with the elbow in hyperflexion.

Immobilization should be maintained until 2 to 4 weeks or evidence of radiographic healing, at which time active exercises should be instituted.

Operative

Adequate reduction of displaced fractures is difficult with closed manipulation. Modified closed reduction involving placement of a Steinmann pin into the fracture fragment with manipulation into the reduced position may be undertaken, with postoperative immobilization consisting of casting with the elbow in hyperflexion.

Excision of the fragment is indicated for fractures in which the fragment is small, comminuted, old (>2 weeks), or not amenable to anatomic reduction without significant dissection of the elbow.

Open reduction and internal fixation may be achieved by the use of two lag screws, headless screws, or Kirschner wires placed posterior to anterior or anterior to posterior. The heads of the screws must be countersunk to avoid intra-articular impingement.

Postoperative immobilization should consist of casting with the elbow in hyperflexion for 2 to 4 weeks depending on stability, with serial radiographic evaluation.

Complications

Osteonecrosis of the capitellar fragment: This is uncommon; synovial fluid can typically sustain the fragment until healing occurs.

Posttraumatic osteoarthritis: This may occur with secondary incongruity from malunion or particularly after a large fragment is excised.

Stiffness: Loss of extension is most common, especially with healing of the fragment in a flexed position. This is typically not significant, because it usually represents the terminal few degrees of extension.

T-Condylar Fractures

Epidemiology

Rare, especially in young children, although this rarity may represent misdiagnosis because purely cartilaginous fractures would not be demonstrated on routine radiographs.

Peak incidence is in patients 12 to 13 years of age.

Anatomy

Because of the muscular origin of the flexor and extensor muscles of the forearm, fragment displacement is related not only to the inciting trauma but also to the tendinous attachments. Displacement therefore includes rotational deformities in both the sagittal and coronal planes.

Fractures in the young child may have a relatively intact distal humeral articular surface despite osseous displacement of the overlying condylar fragments because of the elasticity of the cartilage in the skeletally immature patient.

Mechanism of Injury

Flexion: Most represent wedge-type fractures as the anterior margin of the semilunar notch is driven into the trochlea by a fall onto the posterior aspect of the elbow in >90 degrees of flexion. The condylar fragments are usually anteriorly displaced with respect to the humeral shaft.

Extension: In this uncommon mechanism, a fall onto an outstretched upper extremity results in a wedge-type fracture as the coronoid process of the ulna is driven into the trochlea. The condylar fragments are typically posteriorly displaced with respect to the humeral shaft.

Clinical Evaluation

The diagnosis is most often confused with extension-type supracondylar fractures because the patient typically presents with the elbow extended, with pain, limited range of motion, variable gross deformity, and massive swelling about the elbow.

The ipsilateral shoulder, humeral shaft, forearm, wrist, and hand should be examined for associated injuries.

A careful neurovascular examination is essential, with documentation of the integrity of the median, radial, and ulnar nerves, as well as distal pulses and capillary refill. Massive swelling in the antecubital fossa should alert the examiner to evaluate for compartment syndrome of the forearm. Flexion of the elbow in the presence of antecubital swelling may cause neurovascular embarrassment; repeat evaluation of neurovascular integrity is thus essential following any manipulation or treatment.

All aspects of the elbow should be examined for possible open lesions; clinical suspicion may be followed with intra-articular injection of saline into the elbow to evaluate possible intra-articular

communication of a laceration.

Radiographic Evaluation

Standard AP and lateral views of the injured elbow should be obtained.

Comparison views of the normal, contralateral elbow may be obtained in which the diagnosis is not readily apparent. Oblique views may aid in further fracture definition.

In younger patients, the vertical, intercondylar component may involve only cartilaginous elements of the distal humerus; the fracture may thus appear to be purely supracondylar, although differentiation of the two fracture patterns is important because of the potential for articular disruption and incongruency with T-type fractures. An arthrogram should be obtained when intra-articular extension is suspected.

Computed tomography and MRI are of limited value and are not typically used in the acute diagnosis of T-type fractures. In younger patients, these modalities often require heavy sedation or anesthesia outside of the operating room, in which case an arthrogram is preferred because it allows for evaluation of the articular involvement as well as treatment in the operating room setting.

Classification

Type I: Nondisplaced or minimally displaced

Type II: Displaced, with no metaphyseal comminution

Type III: Displaced, with metaphyseal comminution

Treatment

Nonoperative

This is reserved only for truly nondisplaced type I fractures. Thick periosteum may provide sufficient intrinsic stability such that the elbow may be immobilized in flexion with a posterior splint. Mobilization is continued for 1 to 4 weeks after injury.

Skeletal olecranon traction with the elbow flexed to 90 degrees may be used for patients with extreme swelling, soft tissue compromise, or delayed cases with extensive skin injury that precludes immediate operative intervention. If used as definitive treatment, skeletal traction is usually continued for 2 to 3 weeks, at which time sufficient stability exists for the patient to be converted to a hinged brace for an additional 2 to 3 weeks.

Operative

Closed reduction and percutaneous pinning are used with increasing frequency for minimally displaced type I injuries, in accord with the current philosophy that the articular damage, which cannot be appreciated on standard radiography, may be worse than the apparent osseous involvement.

• Rotational displacement is corrected using a percutaneous joystick in the fracture fragment, with placement of multiple, oblique Kirschner wires for definitive fixation.

• The elbow is then protected in a posterior splint, with removal of pins at 3 to 4 weeks postoperatively.

Open reduction and internal fixation are undertaken for type II and type III fractures using either a

posterior, triceps splitting approach, or the triceps-sparing approach as described by Bryan and Morrey. Olecranon osteotomy is generally not necessary for exposure and should be avoided.

• The articular surface is first anatomically reduced and provisionally stabilized with Kirschner wires, followed by metaphyseal reconstruction with definitive fixation using a combination of Kirschner wires, compression screws, and plates.

• In the pediatric subset, newer and smaller 2.4-, 2.7-, and 3.5-mm precontoured plates have been introduced and fit the smaller anatomy. Usually each column is supported with a plate, often with two plates placed 90 degrees offset from one another.

• Postoperatively, the elbow is placed in a flexed position for 5 to 7 days, at which time active range of motion is initiated and a removable cast brace is provided.

  Complications

Loss of range of motion: T-type condylar fractures are invariably associated with residual stiffness, especially to elbow extension, owing to the often significant soft tissue injury as well as articular disruption. This can be minimized by ensuring anatomic reduction of the articular surface, employing arthrographic visualization if necessary, as well as stable internal fixation to decrease soft tissue scarring.

Neurovascular injury: Rare but is related to significant antecubital soft tissue swelling. Nerve injury to the median, radial, or ulnar nerves may result from the initial fracture displacement or intraoperative traction, although these typically represent neurapraxias that resolve without intervention.

Growth arrest: Partial or total growth arrest may occur in the distal humeral physis, although it is rarely clinically significant because T-type fractures tend to occur in older children. Similarly, the degree of remodeling is limited, and anatomic reduction should be obtained at the time of initial treatment.

Osteonecrosis of the trochlea: This may occur especially in association with comminuted fracture patterns in which the vascular supply to the trochlea may be disrupted.

Radial Head and Neck Fractures

Epidemiology

Of these fractures, 90% involve either physis or neck; the radial head is rarely involved because of the thick cartilage cap.

These represent 5% to 8.5% of elbow fractures.

The peak age of incidence is 9 to 10 years.

Commonly associated fractures include the olecranon, coronoid, and medial epicondyle.

Anatomy

Ossification of the proximal radial epiphysis begins at 4 to 6 years of age as a small, flat nucleus. It may be spheric or may present as a bipartite structure; these anatomic variants may be appreciated by their smooth, rounded borders without cortical discontinuity.

Normal angulation of the radial head with respect to the neck ranges between 0 and 15 degrees laterally and from 10 degrees anterior to 5 degrees posterior angulation.

Most of the radial neck is extracapsular; therefore, fractures in this region may not result in a significant effusion or a positive fat pad sign.

No ligaments attach directly to the radial head or neck; the radial collateral ligament attaches to the orbicular ligament, which originates from the radial aspect of the ulna.

Mechanism of Injury

Acute:

• Indirect: This is most common, usually from a fall onto an outstretched hand with axial load transmission through the proximal radius with trauma against the capitellum.

• Direct: This is uncommon because of the overlying soft tissue mass.

Chronic:

• Repetitive stress injuries may occur, most commonly from overhead throwing activities. Although most “Little League elbow” injuries represent tension injuries to the medial epicondyle, compressive injuries from valgus stress may result in an osteochondrotic-type disorder of the radial head or an angular deformity of the radial neck.

  Clinical Evaluation

Patients typically present with lateral swelling of the elbow, with pain exacerbated by range of motion, especially supination and pronation.

Crepitus may be elicited on supination and pronation.

In a young child, the primary complaint may be wrist pain; pressure over the proximal radius may accentuate the referred wrist pain.

Radiographic Evaluation

AP and lateral views of the elbow should be obtained. Oblique views may aid in further definition of the fracture line.

Special views

• Perpendicular views: With an acutely painful, flexed elbow, AP evaluation of the elbow may be obtained by taking one radiograph perpendicular to the humeral shaft, and a second view perpendicular to the proximal radius.

• Radiocapitellar (Greenspan) view: This oblique lateral radiograph is obtained with the beam directed 45 degrees in a proximal direction, resulting in a projection of the radial head anterior to the coronoid process of the anterior ulna (Fig. 20.1).

A positive supinator fat pad sign may be present, indicating injury to the proximal radius.

Comparison views of the contralateral elbow may help identify subtle abnormalities.

When a fracture is suspected through nonossified regions of the radial head, an arthrogram may be performed to determine displacement.

MRI may be helpful in appreciating the direction of the fracture line and the pattern of fracture.

Classification

O’Brien

This is based on the degree of angulation.

Type I: <30 degrees Type II: 30 to 60 degrees Type III: >60 degrees

Wilkins

This is based on the mechanism of injury.

Valgus injuries are caused by a fall onto an outstretched hand (compression); angular deformity of the head is usually seen (Fig. 44.7).

Type A: Salter-Harris type I or II physeal injury

Type B: Salter-Harris type III or IV intra-articular injury

Type C: Fracture line completely within the metaphysis

Fracture associated with elbow dislocation

• Reduction injury

• Dislocation injury

  Treatment

  Nonoperative

Simple immobilization is indicated for O’Brien type I fractures with <30-degree angulation. This can be accomplished with the use of a collar and cuff, a posterior splint, or a long arm cast for 7 to 10 days with early range of motion.

Type II fractures with 30- to 60-degree angulation should be managed with manipulative closed reduction.

• This may be accomplished by distal traction with the elbow in extension and the forearm in supination; varus stress is applied to overcome the ulnar deviation of the distal fragment and open up the lateral aspect of the joint, allowing for disengagement of the fragments for manipulation (Patterson) (Fig. 44.8).

   

   

   

• Israeli described a technique in which the elbow is placed in flexion, and the surgeon’s thumb is used to apply pressure over the radial head while the forearm is forced into a pronated position (Fig. 44.9).

   

   

   

• Chambers reported another technique for reduction in which an Esmarch wrap is applied distally to proximally, and the radius is reduced by the circumferential pressure.

• Following reduction, the elbow should be immobilized in a long arm cast in pronation with 90

  degrees of flexion. This should be maintained for 10 to 14 days, at which time range-of-motion exercises should be initiated.

  Operative

O’Brien type II fractures (30- to 60-degree angulation) that are unstable following closed reduction may require the use of percutaneous Kirschner wire fixation. This is best accomplished by the use of a Steinmann pin placed in the fracture fragment under image intensification for manipulation, followed by oblique Kirschner wire fixation after reduction is achieved. The patient is then placed in a long arm cast in pronation with 90-degree elbow flexion for 3 weeks, at which time the pins and cast are discontinued and active range of motion is initiated.

Indications for open reduction and internal fixation include fractures that are irreducible by closed means, type III fractures (>60-degree angulation), fractures with >4 mm translation, and medial displacement fractures (these are notoriously difficult to reduce by closed methods). Open reduction with oblique Kirschner wire fixation is recommended; transcapitellar pins are contraindicated because of a high rate of breakage, as well as articular destruction from even slight postoperative motion.

The results of open treatment are not significantly different from those of closed treatment; therefore, closed treatment should be performed when possible.

Radial head excision gives poor results in children owing to the high incidence of cubitus valgus and radial deviation at the wrist due to the continued growth of the child.

Métaizeau has introduced an alternative with the extracapsular reduction of the fracture with a Kirschner wire or flexible intramedullary nail introduced into the medullary canal with a distal metaphyseal entry.

Prognosis

From 15% to 23% will have a poor result regardless of treatment.

Predictors of a favorable prognosis include:

• <10 years of age

• Isolated injury

• Minimal soft tissue injury

• Good fracture reduction

• <30-degree initial angulation

• <3-mm initial displacement

• Closed treatment

• Early treatment

  Complications

Decreased range of motion occurs in (in order of decreasing frequency) pronation, supination, extension, and flexion. The reason is loss of joint congruity and fibrous adhesions. Additionally, enlargement of the radial head following fracture may contribute to loss of motion.

Radial head overgrowth: From 20% to 40% of cases will experience posttraumatic overgrowth of the radial head, owing to increased vascularity from the injury that stimulates epiphyseal growth.

Premature physeal closure: Rarely results in shortening >5 mm, although it may accentuate cubitus valgus.

Osteonecrosis of the radial head: Occurs in 10% to 20%, related to amount of displacement; 70% of cases of osteonecrosis are associated with open reduction.

Neurologic: Usually posterior interosseous nerve neurapraxia; during surgical exposure, pronating the forearm causes the posterior interosseous nerve to move ulnarly, out of the surgical field.

Radioulnar synostosis: The most serious complication, usually occurring following open reduction with extensive dissection, but it has been reported with closed manipulations and is associated with a delay in treatment of >5 days. It may require exostectomy to improve function.

Myositis ossificans: May complicate up to 32% of cases, mostly involving the supinator.

Radial Head Subluxation

Epidemiology

Referred to as “nursemaid’s elbow” or “pulled elbow.”

Male-to-female ratio is 1:2.

Occurs in the left elbow 70% of the time.

Occurs at ages 6 months to 6 years, with a peak at ages 2 to 3 years.

Recurrence rate is 5% to 30%.

Anatomy

Primary stability of the proximal radioulnar joint is conferred by the annular ligament, which closely apposes the radial head within the radial notch of the proximal ulna.

The annular ligament becomes taut in supination of the forearm owing to the shape of the radial head.

The substance of the annular ligament is reinforced by the radial collateral ligament at the elbow joint.

After age 5 years, the distal attachment of the annular ligament to the neck of the radius strengthens significantly to prevent tearing or subsequent displacement.

Mechanism of Injury

Longitudinal traction force on extended elbow is the cause, although it remains controversial whether the lesion is produced in forearm supination or pronation (it is more widely accepted that the forearm must be in pronation for the injury to occur).

Clinical Evaluation

Patients typically present with an appropriate history of sudden, longitudinal traction applied to the extended upper extremity (such as a child “jerked” back from crossing the street), often with an audible snap. The initial pain subsides rapidly, and the patient allows the upper extremity to hang in the dependent position with the forearm pronated and elbow slightly flexed and refuses to use the ipsilateral hand (pseudoparalysis).

A history of a longitudinal pull may be absent in 33% to 50% of cases.

Effusion is rare, although tenderness can usually be elicited over the anterior and lateral aspects of the elbow.

A neurovascular examination should be performed, although the presence of neurovascular compromise should alert the physician to consider other diagnostic possibilities because neurovascular injury is not associated with simple radial head subluxation.

Radiographic Evaluation

Radiographs are not necessary if there is a classic history, the child is 5 years old or younger, and the clinical examination is strongly supportive. Otherwise, standard AP and lateral views of the elbow should be obtained.

Radiographic abnormalities are not typically appreciated, although some authors have suggested that on the AP radiograph >3-mm lateral displacement of the radial head with respect to the capitellum is indicative of radial head subluxation. However, disruption of the radiocapitellar axis is subtle and often obscured by even slight rotation; therefore, even with a high index of suspicion, appreciation of this sign is generally present in only 25% of cases.

Ultrasound is not routinely used in the evaluation of radial head subluxation, but it may demonstrate an increase in the echo-negative area between the radial head and the capitellum (radiocapitellar distance typically about 7.2 mm; a difference of >3 mm between the normal and injured elbow suggests of radial head subluxation).

Classification

A classification scheme for radial head subluxation does not exist.

It is important to rule out other diagnostic possibilities, such as early septic arthritis or proximal radius fracture, which may present in a similar fashion, especially if a history of a longitudinal pull is absent.

Treatment

Closed reduction

• The forearm is supinated with thumb pressure on the radial head.

• The elbow is then brought into maximum flexion with the forearm still in supination.

• Hyperpronation may also be used to reduce the subluxation.

A palpable “click” may be felt on reduction.

The child typically experiences a brief moment of pain with the reduction maneuver, followed by the absence of pain and normal use of the upper extremity 5 to 10 minutes later.

Postreduction films are generally unnecessary. A child who remains irritable may require further workup for other disorders or a repeat attempt at reduction. If the subluxation injury occurred 12 to 24 hours before evaluation, reactive synovitis may be present that may account for elbow tenderness and a reluctance to move the joint.

Sling immobilization is generally unnecessary if the child is able to use the upper extremity without complaint.

Complications

Chronically unreduced subluxation: Unrecognized subluxation of the radial head generally reduces spontaneously with relief of painful symptoms. In these cases, the subluxation is realized retrospectively.

Recurrence: Affects 5% to 39% of cases but generally ceases after 4 to 5 years when the annular ligament strengthens, especially at its distal attachment to the radius.

Irreducible subluxation: Rare owing to interposition of the annular ligament. Open reduction may be necessary with transection and repair of the annular ligament to obtain stable reduction.

Elbow Dislocations

Epidemiology

Represent 3% to 6% of all elbow injuries.

The peak age is 13 to 14 years, after physes are closed.

There is a high incidence of associated fractures: medial epicondyle, coronoid, and radial head and neck.

Anatomy

This is a “modified hinge” joint (ginglymoid) with a high degree of intrinsic stability owing to joint congruity, opposing tension of triceps and flexors, and ligamentous constraints. Of these, the

anterior bundle of the medial collateral ligament is the most important.

Three separate articulations

• Ulnohumeral (hinge)

• Radiohumeral (rotation)

• Proximal radioulnar (rotation)

Stability

• AP: Trochlea/olecranon fossa (extension); coronoid fossa, radiocapitellar joint, biceps/triceps/brachialis (flexion)

• Valgus: Medial collateral ligament complex (anterior bundle the primary stabilizer [flexion and

  extension]) anterior capsule and radiocapitellar joint (extension)

• Varus: Ulnohumeral articulation, lateral ulnar collateral ligament (static); anconeus muscle (dynamic)

Range of motion is 0 to 150 degrees of flexion, 85 degrees of supination, and 80 degrees of

pronation.

Functionally, range of motion requires 30 to 130 degrees of flexion, 50 degrees of supination, and 50 degrees of pronation.

Extension and pronation are the positions of relative instability.

Mechanism of Injury

Most commonly, the cause is a fall onto an outstretched hand or elbow, resulting in a levering force to unlock the olecranon from the trochlea combined with translation of the articular surfaces to produce the dislocation.

Posterior dislocation: This is a combination of elbow hyperextension, valgus stress, arm abduction, and forearm supination with resultant soft tissue injuries to the capsule, collateral ligaments (especially medial), and musculature.

Anterior dislocation: A direct force strikes the posterior aspect of the flexed elbow.

Clinical Evaluation

Patients typically present guarding the injured upper extremity with variable gross instability and massive swelling.

A careful neurovascular examination is crucial and should be performed before radiographs or manipulation. At significant risk of injury are the median, ulnar, radial, and anterior interosseous nerves and the brachial artery.

Serial neurovascular examinations should be performed when massive antecubital swelling exists or the patient is believed to be at risk for compartment syndrome.

Following manipulation or reduction, repeat neurovascular examinations should be performed to monitor neurovascular status.

Angiography may be necessary to identify vascular compromise. The radial pulse may be present with brachial artery compromise as a result of collateral circulation.

Radiographic Evaluation

Standard AP and lateral radiographs of the elbow should be obtained.

Radiographs should be scrutinized for associated fractures about the elbow, most commonly disruption of the apophysis of the medial epicondyle, or fractures involving the coronoid process and radial neck.

Classification

Chronologic: Acute, chronic (unreduced), or recurrent.

Descriptive: Based on the relationship of the proximal radioulnar joint to the distal humerus.

Posterior:

• Posterolateral: >90% dislocations

• Posteromedial

Anterior: Represents only 1% of pediatric elbow dislocations.

Divergent: This is rare.

Medial and lateral dislocations: These are not described in the pediatric population.

Fracture-dislocation: Most associated osseous injuries involve the coronoid process of the olecranon, the radial neck, or the medial epicondylar apophysis of the distal humerus. Rarely, shear fractures of the capitellum or trochlea may occur.

Treatment

Posterior Dislocation

Nonoperative

Acute posterior elbow dislocations should be initially managed with closed reduction using sedation and analgesia. Alternatively, general or regional anesthesia may be used.

Young children (0 to 8 years old): With the patient prone and the affected forearm hanging off the edge of the table, anteriorly directed pressure is applied to the olecranon tip, effecting reduction.

Older children (>8 years old): With the patient supine, reduction should be performed with the forearm supinated and the elbow flexed while providing distal traction (Parvin). Reduction with the elbow hyperextended is associated with median nerve entrapment and increased soft tissue trauma.

Neurovascular status should be reassessed, followed by evaluation of stable range of motion.

Postreduction radiographs are essential.

Postreduction management should consist of a posterior splint at 90 degrees with loose circumferential wraps and elevation. Attention should be paid to antecubital and forearm swelling.

Early, gentle, active range of motion 5 to 7 days after reduction is associated with better long-term results. Forced, passive range of motion should be avoided because redislocation may occur. Prolonged immobilization is associated with unsatisfactory results and greater flexion contractures.

A hinged elbow brace through a stable arc of motion may be indicated in cases of instability without associated fractures.

Full recovery of motion and strength requires 3 to 6 months.

Operative

Indicated for cases of soft tissue and/or bony entrapment in which closed reduction is not possible.

A large, displaced coronoid fragment requires open reduction and internal fixation to prevent recurrent instability. Medial epicondylar apophyseal disruptions with entrapped fragments must be addressed.

Lateral ligamentous reconstruction in cases of recurrent instability and dislocation is usually unnecessary.

An external fixator for grossly unstable dislocations (with disruption of the medial collateral ligament) may be required as a salvage procedure.

Anterior Dislocation

Acute anterior dislocation of the elbow may be managed initially with closed reduction using sedation and analgesia.

Initial distal traction is applied to the flexed forearm to relax the forearm musculature, followed by dorsally directed pressure on the volar forearm coupled with anteriorly directed pressure on the distal humerus.

Triceps function should be assessed following reduction, because stripping of the triceps tendon from its olecranon insertion may occur.

Associated olecranon fractures usually require open reduction and internal fixation.

Divergent Dislocation

This is a rare injury, with two types:

• Anterior–posterior type (ulna posteriorly, radial head anteriorly): This is more common; reduction is achieved in the same manner as for a posterior dislocation concomitant with posteriorly directed pressure over the anterior radial head prominence.

• Mediolateral (transverse) type (distal humerus wedged between radius laterally and ulna medially): This is extremely rare; reduction is by direct distal traction on extended elbow with pressure on the proximal radius and ulna, converging them.

  Complications

Loss of motion (extension): This is associated with prolonged immobilization with initially unstable injuries. Some authors recommend posterior splint immobilization for 3 to 4 weeks, although recent trends have been to begin early (1 week), supervised range of motion. Patients typically experience a loss of the terminal 10 to 15 degrees of extension, which is usually not functionally significant.

Neurologic compromise: Neurologic deficits occur in 10% of cases. Most complications occur with entrapment of the median nerve. Ulnar nerve injuries are most commonly associated with disruptions of the medial epicondylar apophysis. Radial nerve injuries occur rarely.

• Spontaneous recovery is usually expected; a decline in nerve function (especially after

  manipulation) or severe pain in nerve distribution is an indication for exploration and decompression.

• Exploration is recommended if no recovery is seen after 3 months following electromyography and serial clinical examinations.

Vascular injury (rare): The brachial artery is most commonly disrupted during injury.

• Prompt recognition of vascular injury is essential, with closed reduction to reestablish perfusion.

• If, after reduction, perfusion is not reestablished, angiography is indicated to identify the lesion,

  with arterial reconstruction with reverse saphenous vein graft when indicated.

Compartment syndrome (Volkmann contracture): May result from massive swelling from soft tissue injury. Postreduction care must include aggressive elevation and avoidance of hyperflexion of the elbow. Serial neurovascular examinations and compartment pressure monitoring may be necessary, with forearm fasciotomy when indicated.

Instability/redislocation: Rare (<1%) after isolated, traumatic posterior elbow dislocation; the incidence is increased in the presence of associated coronoid process and radial head fracture (combined with elbow dislocation, this completes the terrible triad of the elbow). It may necessitate hinged external fixation, capsuloligamentous reconstruction, internal fixation, or prosthetic replacement of the radial head.

Heterotopic bone/myositis ossificans: This occurs in 3% of pure dislocations, 18% when associated with fractures, most commonly caused by vigorous attempts at reduction.

• Anteriorly, it forms between the brachialis muscle and the capsule; posteriorly, it may form medially or laterally between the triceps and the capsule.

• The risk is increased with a greater degree of soft tissue trauma or the presence of associated

  fractures.

• It may result in significant loss of function.

• Forcible manipulation or passive stretching increases soft tissue trauma and should be avoided.

• Indomethacin or local radiation therapy is recommended for prophylaxis postoperatively and in the presence of significant soft tissue injury and/or associated fractures. Radiation therapy is contraindicated in the presence of open physes.

Osteochondral fractures: Anterior shear fractures of the capitellum or trochlea may occur with anterior dislocations of the elbow. The presence of an unrecognized osteochondral fragment in the joint may be the cause of an unsatisfactory result of what initially appeared to be an uncomplicated elbow dislocation.

Radioulnar synostosis: The incidence is increased with an associated radial neck fracture.

Cubitus recurvatum: With significant disruption of the anterior capsule, hyperextension of the elbow may occur late, although this is rarely of any functional or symptomatic significance.

Olecranon Fractures

Epidemiology

These account for 5% of all elbow fractures.

The peak age is 5 to 10 years.

Twenty percent have an associated fracture or dislocation; the proximal radius is the most common.

Anatomy

The olecranon is metaphyseal and has a relatively thin cortex, which may predispose the area to greenstick-type fractures.

The periosteum is thick, which may prevent the degree of separation seen in adult olecranon fractures.

The larger amount of epiphyseal cartilage may also serve as a cushion to lessen the effects of a direct blow.

Mechanism of Injury

Flexion injuries: With the elbow in a semiflexed position, the pull of the triceps and brachialis muscles places the posterior cortex in tension; this force alone, or in combination with a direct blow, may cause the olecranon to fail. The fracture is typically transverse.

Extension injuries: With the arm extended, the olecranon becomes locked in the olecranon fossa; if a varus or valgus force is then applied, stress is concentrated in the distal aspect of the olecranon; resultant fractures are typically greenstick fractures that remain extra-articular and may extend proximal to the coronoid process.

Shear injuries: A direct force is applied to the posterior olecranon, resulting in tension failure of the anterior cortex; the distal fragment is displaced anteriorly by the pull of the brachialis and biceps; this is differentiated from the flexion-type injury by an intact posterior periosteum.

Clinical Evaluation

Soft tissue swelling is typically present over the olecranon.

An abrasion or contusion directly over the olecranon may indicate a flexion-type injury.

The patient may lack active extension, although this is frequently difficult to evaluate in an anxious child with a swollen elbow.

Radiographic Evaluation

Standard AP and lateral x-rays of the elbow should be obtained.

Fracture lines associated with a flexion injury are perpendicular to the long axis of the olecranon; these differentiate the fracture from the residual physeal line, which is oblique and directed proximal and anterior.

The longitudinal fracture lines associated with extension injuries may be difficult to appreciate.

The radiographs should be scrutinized to detect associated fractures, especially proximal radius fractures.

Classification

Group A: Flexion injuries

Group B: Extension injuries

1. Valgus pattern

2. Varus pattern

Group C: Shear injuries

Treatment

Nonoperative

Nondisplaced flexion injuries are treated with splint immobilization in 5 to 10 degrees of flexion for 3 weeks; radiographs should be checked in 5 to 7 days to evaluate for early displacement.

Extension injuries generally need correction of the varus or valgus deformity; this may be accomplished by locking the olecranon in the olecranon fossa with extension and applying a varus or valgus force to reverse the deformity; overcorrection may help to prevent recurrence of the deformity.

Shear injuries can be treated with immobilization in a hyperflexed position if the posterior periosteum remains intact, with the posterior periosteum functioning as a tension band; operative intervention should be considered if excessive swelling is present that may result in neurovascular compromise in a hyperflexed position.

Operative

Displaced or comminuted fractures may require surgical stabilization.

Determining whether the posterior periosteum is intact is key to determining the stability of a fracture; if a palpable defect is present, or if the fragments separate with flexion of the elbow, internal fixation may be needed.

Fixation may be achieved with Kirschner wires and a tension band, tension band alone, cancellous screws alone, or cancellous screws and tension band.

Removal of hardware is frequently required and should be considered when deciding on a fixation technique (i.e., tension band with wire vs. tension band with suture).

Postoperatively, the elbow is immobilized in a cast at 70 to 80 degrees of flexion for 3 weeks, after which active motion is initiated.

Complications

Delayed union: Rare (<1%) and is usually asymptomatic, even if it progresses to a nonunion.

Nerve injury: Rare at the time of injury; ulnar neurapraxia has been reported after development of a pseudarthrosis of the olecranon when inadequate fixation was used.

Elongation: Elongation of the tip of the olecranon may occur after fracture; the apophysis may elongate to the point that it limits elbow extension.

Loss of reduction: Associated with fractures treated nonoperatively that subsequently displace; it may result in significant loss of elbow function if it is not identified early in the course of treatment.