Pediatric Elbow and Forearm Conditions

Joshua M. Abzug

Danielle A. Hogarth

Dan A. Zlotolow

• Introduction

Outside of the hand, the elbow is the most critical joint for the function of the upper limb. Therefore, preservation and restoration of stability and motion, in that order, are the highest priorities when treating elbow and forearm pathology. Forearm axial stability is also important, particularly as it affects the elbow and the wrist. Any pathology of the elbow or the forearm that affects the relative lengths of the radius and ulna can lead to dysfunction, deformity, and/or pain at the wrist. Likewise, some of the muscles of the forearm cross both the elbow and the wrist, and all of the muscles that originate in the forearm cross the wrist, except for the pronator quadratus. Primary and secondary muscle/tendon dysfunction can also affect the wrist. Any examination of the elbow and forearm must also at least consider potential pathology at the wrist as well. Common pathologies that afflict the pediatric elbow and forearm include congenital, traumatic, neurologic, neoplastic, sport-related, and other various conditions.

Congenital differences are present at birth but are occasionally not diagnosed until later in life. For example, radial head dislocations and radioulnar synostoses are often diagnosed after 5 years old, when limitations of forearm motion become limiting for recreational activities. Other congenital differences are immediately apparent at birth, such as congenital amputations, but much to the surprise of the parents commonly are not diagnosed in utero. This presents a difficult time for the family.”¹,²

Traumatic injuries to the elbow and forearm are very common in children and include fractures, dislocations, and soft tissue injuries. Because a child’s ligaments are typically stronger than their bones, avulsion injuries are common. Plastic deformation can likewise pose diagnostic and treatment challenges. The pediatric elbow in young children is also particularly problematic diagnostically because of its large cartilaginous component, even past mid-childhood. Monteggia fracture-dislocations are often missed because of the combination of plastic deformation of the ulna and incomplete ossification of the capitellum. Likewise, medial condyle and epicondylar fractures are commonly missed or underappreciated because of the lack of ossification of the trochlea.

Pediatric tumors of bone in the elbow and forearm are most commonly benign lesions. Osteocartilaginous tumors can be seen inside the bone (enchondroma), on the surface of a bone (sessile osteochondroma), or growing out from the bone (pedunculated osteochondroma). Soft tissue tumors are most commonly hematologic in origin. Malignant neoplasms are rare but do occur, so an appropriate index of suspicion is warranted.

Neurologic disorders that affect the elbow and forearm can be local affecting the peripheral nervous system, such as cubital tunnel syndrome, or more proximal, such as cerebral palsy, which affects the central nervous system. Proximal neurologic disorders, such as a brachial plexus injury, that involve the elbow and forearm are typically more difficult to treat because they often comprise a larger scope of injury. Children with cerebral palsy can not only develop contractures of their elbow and forearm but also can exhibit athetoid movements or poor volitional muscle control.

Lastly, as sports participation and intensity have increased in the pediatric population, so have the prevalence and severity of sports-related injuries. The elbow of the growing child is particularly
susceptible to overuse injuries from repetitive valgus overload, as seen in pitching and upper-limb weight-bearing sports. Typically, it is the most competitive and hardworking junior athletes who place themselves at the highest risk.

• General Physical Examination

Any examination of the elbow and forearm should include the shoulder, wrist, and hand. Although specific tests will be covered under specific diagnoses, the general upper limb examination detailed below should routinely be performed on all patients when possible. Children who are unable to follow commands may be lured to instead follow objects placed just out of reach. Stickers placed on the palm or back of the hand can also be used to induce supination or pronation, respectively.

Observation

All physical examinations should initially begin with observation of the child, looking for normal growth and development, deformities, skin lesions, and use of the limb in the office. For the majority of diagnoses, the contralateral limb can be utilized as a “normal” comparison, but this is certainly not true for all diagnoses. For an acute complaint, the skin should be assessed for swelling, tissue loss, ecchymosis, deformity, abrasions, etc. The carrying angle, an angle that defines the alignment of the limb at the elbow, can be observed and compared between sides. This angle is formed between the long axis of the humerus and the long axis of the forearm and is typically 11° to 14° of valgus in children (Figure 18.1). Overhead throwers will commonly have a greater carrying angle due to the repetitive valgus stresses placed on the elbow during the sports activities. Cubitus varus or “gunstock” deformity is commonly the result of a malunion about the elbow (Figures 18.2 and 18.3).

Topographical Inspection by Palpation

The next component of the physical examination should include palpation of anatomic landmarks. It is always optimal to begin away from the symptomatic area and progress toward it to gain trust with the child as well as to minimize any unnecessary discomfort during the examination. The bony landmarks about the elbow should be palpated purposefully to aid the practitioner during the examination. One should not just “grab” the elbow with a whole hand to determine tenderness. Rather, the structures about the elbow should be palpated utilizing 1 to 2 fingers so that the practitioner can differentiate the true areas of tenderness. The areas that should be palpated in particular include the supracondylar region, the lateral aspect of the joint and capitellum, the medial epicondyle, the radial neck, and the olecranon. One should also palpate the lateral “soft spot” to assess for fullness that may indicate a joint effusion. Palpation of the forearm should include assessing for any areas of tenderness, fullness, and/or abnormal bony anatomy (

Video 18.1).

FIGURE 18.1 Clinical photograph of a 5-year-old child with 12° of valgus measured between the long axis of the humerus and the long axis of the forearm. (Courtesy of Joshua M. Abzug, MD.)

FIGURE 18.2 Radiographs of a 5-year-old child with cubitus varus after sustaining a displaced supracondylar fracture healed in malroation and in varus deformity. A, Anteroposterior view. B, Lateral view. C, Oblique view. (Courtesy of Joshua M. Abzug, MD.)

Range of Motion

Active and passive range of motion should be assessed in all children. The normal range of motion about the elbow is approximately 140° of flexion and 0° to -10° of hyperextension. A goniometer should be utilized during the examination to obtain true values. Normal forearm supination is approximately 85° and pronation is approximately 60° to 70°. Careful assessment must be performed to assess for true forearm rotation as opposed to pseudorotation that is occurring through the carpus when the examiner rotates the forearm by the hand (Figure 18.4). Therefore, the examiner should assess forearm pronation-supination by rotation at the distal 1/3 of the forearm as opposed to holding at the hand (

Video 18.2).

FIGURE 18.3 Clinical photograph of a 5-year old child with cubitus varus on the right. Carrying angle is 25° of varus, whereas the normal left side has a carrying angle of 8° of valgus. (Courtesy of Joshua M. Abzug, MD.)

Shoulder Abduction, Elbow Extension

With the patient either sitting or supine, instruct the patient to reach as high as they can away from the body. This tests both shoulder abduction and elbow extension. If the patient is unable to abduct the shoulder, elbow extension will have to be tested independently by the examiner holding the shoulder in abduction and asking the patient to reach as high as they can. If the patient is unable to extend the elbow, they may be reluctant to abduct the shoulder, so as to not hit themselves in the face or on the head with their hand when their elbow collapses.

Shoulder External Rotation, Elbow Flexion

Instruct the patient to reach for the back of their neck. This assessed shoulder external rotation and also tests elbow flexion at the same time. If the patient is unable to externally rotate the shoulder, test elbow flexion independently by asking the patient to reach for their mouth. If the patient is unable to abduct the shoulder, test for external rotation with the elbows at the side.

FIGURE 18.4 This 5-year-old girl with congenital radioulnar synostosis has apparent rotation even though the proximal forearm is fused. This motion occurs at the wrist and not the forearm.

Elbow Flexion, Forearm Rotation

With the elbows at the side and flexed approximately 90°, instruct the patient to turn the palms up and down. Forearm motion is assessed by looking and feeling for the relative positions of the radius and ulna, not the position of the hand, as the wrist itself can produce up to 60° of pronation and supination.³

Wrist Flexion and Extension, Radial and Ulnar Deviation

Test passive extension by instructing the patient to place the palms together with the fingers pointing to the ceiling and raise their elbows up while keeping the hands down. Test passive flexion by instructing the patient to place the back of the hands together with the fingers pointing to the floor and lower their elbows while keeping the hands up. Active extension is tested with the forearm in pronation, and active flexion is tested with the forearm in supination. Radial and ulnar deviation require a hands-on approach from the examiner to assess passive movement. The wrist should be moved into radial, and then ulnar deviation. Pain with ulnar deviation should be noted as a sign of ulnocarpal impaction.

Overall Stability

Following the assessment of a range of motion, one can assess the stability of the elbow, although this examination is quite limited in an awake child due to co-contraction of muscles, pain, and fear. The lateral ligamentous structures can be assessed by applying a varus force while internal rotation is applied to the elbow, with the elbow flexed about 30°. In contrast, the medial ligamentous structures can be assessed by applying a valgus force with external rotation to the elbow, with the elbow flexed about 30°. One can attempt to perform the posterolateral pivot shift test to assess the lateral ligamentous complex by applying a valgus and axial load to the elbow while flexing the elbow with the forearm in supination and arm overhead. A positive test implies posterolateral subluxation when there is a clunk with greater than 40° of flexion (

Video 18.3).

Neurovascular Examination

A neurovascular examination should also be performed on all patients. This includes a motor and sensory assessment of the peripheral nerves throughout the upper extremity (

Video 18.4). Although the examination needs to be focused depending on the complaints, the major peripheral nerves including the median, ulnar, and radial nerves should be assessed in all patients. In younger patients, this may be difficult but certain maneuvers can be helpful. For example, one can utilize the tenodesis effect to assess for tendon continuity following a forearm laceration. Alternatively, the forearm musculature can be squeezed in a young child, and the hand can be observed for digital flexion. Knowledge of tendon congruity can aid in differentiating a tendon injury from a nerve injury.

When evaluating potential sensory injuries, normative data in the pediatric population have been established for Semmes-Weinstein monofilament testing, as well as moving and static two-point discrimination.⁴ Threshold testing utilizing a monofilament can be performed uniformly in children as young as 5 years of age and density testing utilizing two-point discrimination can be performed in children as young as 7 years old.⁴ An examiner can also assess for sensibility in the younger child utilizing the wrinkle test, where the hand is placed in cold water for 5 minutes and wrinkling of the skin occurs in the digits that have intact neurological input. Parts of the hand that do not wrinkle are likely denervated.

The vascular assessment of the limb begins with the observation of the color of the skin. Additionally, the temperature of the digits should be noted, and capillary refill testing can be performed. One should then palpate the radial and ulnar pulses and compare the strength of the palpation with the contralateral limb. The hands should be pink and warm (Figure 18.5).

FIGURE 18.5 Clinical photograph of a bilateral vascular assessment of the hands demonstrating adequate pink coloration. (Courtesy of Joshua M. Abzug, MD.)

• Congenital Differences

Coronoid Insufficiency

Introduction

Coronoid insufficiency is rare and presents typically in early adolescence with either recurrent or chronic elbow dislocation. Because of the late presentation, and because elbow trauma is ubiquitous in children, differentiating a congenital from a posttraumatic coronoid insufficiency is nearly impossible, but may have some relevance in management.

History and Physical Examination

On examination, the elbow becomes unstable axially with increasing extension. Once reduced, there is no varus or valgus instability.

Differential Diagnosis

Heterotopic ossification is a sign that the etiology may be traumatic in origin and not congenital insufficiency. Pain is typically not a factor in congenital insufficiency but is often seen with posttraumatic deficiencies.

Diagnostic Tests or Advanced Imaging

A global assessment of the elbow bony anatomy is important and may require either an arthrogram or a magnetic resonance imaging (MRI) in addition to palpation and range of motion assessment. If the elbow is completely ossified, a CT scan with 3D reconstruction is preferred. The coronoid is either small or absent while the remainder of the elbow is typically unaffected.

Radial Head Dislocation

Introduction

Differentiating between posttraumatic and congenital radial head dislocations is often a matter of conjecture, as birth trauma can result in a radial head dislocation.⁷ It is our belief that the vast majority of “congenital” radial head dislocations are missed Monteggia fracture-dislocations or nursemaid’s elbows, either from birth trauma or early childhood trauma. However, bilateral radial head dislocations are more likely to truly be a congenital condition in nature.

History and Physical Examination

Children often present in late childhood when restricted forearm motion is functionally limiting or when the child or parents notice a “mass” on the posterolateral aspect of the elbow. Other symptoms such as a limitation of elbow flexion can be seen if the radial head is anteriorly dislocated. Lateral dislocations are typically the most benign, as the position of the radial head does not interfere with elbow motion but does promote valgus instabiity. Medial dislocations present with gross valgus instability and limited elbow flexion.

Differential Diagnosis

One possible differentiator of congenital as opposed to traumatic radial head dislocations may be the development of the capitellum. A normal convex capitellum suggests that there was a radial head to contour against at least at some point in development (Figure 18.6). We consider all radial head dislocations with a normal capitellum to be of traumatic origin. Likewise, all patients with an irregularly angled ulna are managed as missed Monteggia fracture-dislocations (Figure 18.7).

Diagnostic Tests or Advanced Imaging

Plain radiographs are typically sufficient to obtain the diagnosis. A CT scan and/or MRI can be obtained if one thinks the dislocation is traumatic in origin, such as a missed Monteggia fracture-dislocation, and preoperative assessment is being considered.

Treatment

The keys to treating radial head dislocations are to determine (1) the cause of the dislocation, (2) the timing of the dislocation, (3) if it is reducible, and (4) if the radial head/capitellar anatomy would allow/sustain a reduction. Congenital radial head dislocations have so far proven difficult if not impossible to reduce. However, neonatal Monteggia injuries are amenable to relocation, particularly with the use of three-dimensional modeling techniques.⁷ Restoring the bony anatomy is the most important component, with annular ligament reconstruction often not required. Reducible/dislocatable joints can be stabilized with an annular ligament reconstruction. Our annular ligament reconstruction transfers the distal biceps tendon to the medial origin footprint of the annular ligament, with half of the tendon left in continuity and the other half passed over the radial head, under the PIN, and docked into the footprint of the lateral annular ligament origin.

FIGURE 18.6 This adolescent male has likely congenital dislocation as his mother has similar radiographs. The capitellum is hypoplastic (yellow arrow) and the proximal radius is elongated and the radial head lacks the normal concave appearance (red arrow).

FIGURE 18.7 This child with an anterior dislocation radial head (red arrow) is likely a missed Monteggia as evidenced by anterior ulna bow that is normally straight (white line) and with evidence of old fracture (yellow arrow).

Radioulnar Synostosis

Introduction

Radioulnar synostosis is a rare, congenital condition where parts of the radius and ulna fail to separate. This congenital condition limits forearm rotation, so limitations are functionally relevant.

History and Physical Examination

Typically, the presentation is delayed until late childhood when the child is attempting to catch a ball. Children with extreme rotational positions (beyond 30° of supination or 60° of pronation) will present earlier. Parents will often assert that the loss of motion is new and in many instances provide photographic mis-evidence of such. The child will have no motion at the forearm, but typically will demonstrate hyperrotation at the radiocarpal joint, even up to 60° of both pronation and supination.⁸

Diagnostic Tests or Advanced Imaging

Plain radiographs are pathognomonic (Figure 18.8), and there is nothing else in the differential.

FIGURE 18.8 Radiograph of elbow demonstrating proximal radioulnar synostosis. A, Anteroposterior view and (B) lateral view. (Courtesy of Joshua M. Abzug, MD.)

Transverse Deficiencies

Introduction

Congenital transverse deficiencies are very commonly misdiagnosed as resulting from amnionic bands. Although amniotic bands are a cause of congenital amputation, more common causes such as symbrachydactyly are not well known to frontline providers (Figure 18.9). Transverse deficiencies most often are due to a failure of formation or differentiation, rather than from intrauterine amputation. Loss of the apical ectodermal ridge (AER) results in hypodactyly or cleft hand, loss of mesoderm results in symbrachydactyly with or without Poland syndrome, and loss of the zone of polarizing activity (ZPA) results in ulnar deficiency with or without thumb dysplasia.

Only gold members can continue reading. Log In or Register to continue