Brachial Plexus Birth Palsy

Injuries to the brachial plexus can occur in the peripartum time, usually as a result of a stretching mechanism. This palsy is often associated with large fetal size and shoulder dystocia. The incidence is 1-3/1,000 live births. The injury can range in severity from neurapraxia to complete rupture of the nerve root or avulsion of the nerve root from the spinal cord. More often, the upper roots (C5 and C6) are affected rather than a complete brachial plexus palsy. Rarely, in isolation, a lower plexus injury (C8 and T1) is observed. The clinical appearance of a C5-6 brachial plexus birth palsy is the waiter’s tip position. The arm is held in a position of shoulder adduction and internal rotation, elbow extension, and wrist flexion. This is the classic Erb’s palsy.

Sprengel’s Deformity

Sprengel’s deformity, or congenital elevation of the scapula, is a disorder of development that involves a high scapula and limited scapulothoracic motion. The scapula originates in early embryogenesis at a level posterior to the 4th cervical vertebra, but it descends during development to below the 7th cervical vertebra. Failure of this descent, either unilateral or bilateral, is the Sprengel deformity. The severity of the deformity depends on the location of the scapula and associated anomalies. The scapula in mild cases is simply rotated, with a palpable or visible bump corresponding to the superomedial corner of the scapula in the region of the trapezius muscle. Function is generally good. In moderate cases, the scapula is higher on the neck and connected to the spine with an abnormal omovertebral ligament or even bone. Shoulder motion, particularly abduction, is limited. In severe cases, the scapula is small and positioned on the posterior neck, and the neck may be webbed. The majority of patients have associated anomalies of the musculoskeletal system, especially in the spine, making spinal evaluation important.

Panner’s Disease

Panner’s disease is a disruption of the blood flow to the articular cartilage and subchondral bone to the capitellum (Fig. 673-1). It typically occurs in boys between the ages of 5 and 13 yr. Presenting symptoms include lateral elbow pain, loss of motion, and, in advanced cases, mechanical symptoms of the elbow.

Figure 673-1 T1 (A) and T2 (B) coronal MRI images of the elbow depicting Panner disease of the elbow.

The mechanism of injury can be impaction or overloading of the joint, as seen with sports such as gymnastics and baseball. It can also be idiopathic. Radiographs of the elbow may be normal, but they can also show a small lucency within the capitellum. MRI is the study of choice to evaluate a suspected capitellar lesion. It can demonstrate the extent of the lesion as well as the integrity of the articular surface better than plain radiographs.

Radial Longitudinal Deficiency

Radial longitudinal deficiency of the forearm comprises a spectrum of conditions and diseases that have resulted in hypoplasia or absence of the radius (Table 673-1). This process was formerly referred to as radial club hand, but the name has been changed to radial longitudinal deficiency, which better characterizes the condition. Clinical characteristics consist of a small, shortened limb with the hand and wrist in excessive radial deviation.

Table 673-1 SYNDROMES COMMONLY ASSOCIATED WITH RADIAL DEFICIENCY

From Trumble T, Budoff J, Cornwall R, editors: Core knowledge in orthopedics: hand, elbow, shoulder, Philadelphia, 2005, Elsevier, p 425.

Radial longitudinal deficiency can range in severity from mild to severe and has been classified into four types according to Bayne and Klug (Table 673-2). Radial longitudinal deficiency can be associated with other syndromes such as Holt-Oram and Fanconi’s anemia.

Table 673-2 CLASSIFICATION OF RADIAL LONGITUDINAL DEFICIENCY

Adapted from Bayne LG, Klug MS: Long-term review of the surgical treatment of radial deficiencies, J Hand Surg Am 12(2):169–179, 1987.

Nursemaid Elbow

Nursemaid elbow is a subluxation of a ligament rather than a subluxation or dislocation of the radial head. The proximal end of the radius, or radial head, is anchored to the proximal ulna by the annular ligament, which wraps like a leash from the ulna, around the radial head, and back to the ulna. If the radius is pulled distally, the annular ligament can slip proximally off the radial head and into the joint between the radial head and the humerus (Fig. 673-2). The injury is typically produced when a longitudinal traction force is applied to the arm, such as when a falling child is caught by the hand, or when a child is pulled by the hand. The injury usually occurs in toddlers and rarely occurs in children >5 yr of age. Subluxation of the annular ligament produces immediate pain and limitation of supination. Flexion and extension of the elbow are not limited, and swelling is generally absent. The diagnosis is made by history and physical examination, as radiographs are typically normal.

Figure 673-2 The pathology of nursemaid, or pulled, elbow. The annular ligament is partially torn when the arm is pulled. The radial head moves distally, and when traction is discontinued, the ligament is carried into the joint.

(From Rang M: Children’s fractures, ed 2, Philadelphia, 1983, JB Lippincott, p 193.)

Madelung’s Deformity

Madelung’s deformity is a deformity of the wrist that is characterized as radial and palmar angulations of the distal aspect of the radius. Growth arrest of the palmar and ulnar aspect of the distal radial physis is the underlying cause of this deformity. Bony physeal lesions and an abnormal radiolunate ligament (Vicker ligament) have been implicated. The deformity can be bilateral and affects girls more than boys.

Ganglion

As a synovial joint, the wrist articulation is lubricated with synovial fluid, which is produced by the synovial lining of the joint and maintained within the joint by the joint capsule. A defect in the capsule can allow fluid to leak from the joint into the soft tissues, resulting in a ganglion. The term cyst is a misnomer, because this extra-articular collection of fluid does not have its own true lining. The defect in the capsule can occur as a traumatic event, although trauma is rarely a feature of the presenting history. The fluid usually exits the joint in the interval between the scaphoid and lunate, resulting in a ganglion located at the dorsoradial aspect of the wrist. Ganglia can occur at other locations, such as the volar aspect of the wrist, or in the palm as a result of leakage of fluid from the flexor tendon sheaths. Pain is not commonly associated with ganglia in children, and when it is, it is unclear whether the cyst is the cause of the pain. The diagnosis is usually evident on physical examination, especially if the lesion transilluminates. Extensor tenosynovitis and anomalous muscles can mimic ganglion cysts, but radiography or MRI is not routinely required. Ultrasonography is an effective, noninvasive tool to support the diagnosis and reassure the patient and family.

Camptodactyly

Camptodactyly is a nontraumatic flexion contracture of the proximal interphalangeal joint that is often progressive. The small and ring fingers are most often affected. Bilateralism is observed two thirds of the time. The etiology of camptodactyly is varied. Several different hypotheses have been offered as to the cause of this condition. Camptodactyly can be divided into three different types (Table 673-3).

Table 673-3 CLASSIFICATION OF CAMPTODACTYLY

Adapted from Kozin SH: Pediatric hand surgery. In Beredjiklian PK, Bozentka DJ, editors: Review of hand surgery, Philadelphia, 2004, WB Saunders, pp 223–245.

Clinodactyly

Angular deformity of the digit in the coronal plane, distal to the metacarpophalangeal joint is clinodactyly. The most commonly observed finding is a mild radial deviation of the small finger at the level of the distal interphalangeal joint. This is often due to a triangular or trapezoidal middle phalanx. In some cases, a disruption of the physis at the middle phalanx produces a longitudinal epiphysial bracket. This bracket is thought to be the underlying cause for the formation the “delta phalanx” that is often observed in clinodactyly. Clinodactyly has been observed in other fingers, including the thumb (Fig. 673-3) and ring finger.

Figure 673-3 Clinodactyly of the thumb.

Polydactyly

Polydactyly or duplication of a digit can occur either as a preaxial deformity (involving the thumb) or as a post axial deformity (involving the small finger) (Table 673-4). Each has an inherited and genetic component. Duplication of the thumb occurs more in white children and is often unilateral, whereas duplication of the small finger occurs mainly in African-Americans and may be bilateral. Transmission is typically in an autosomal dominant pattern and has been linked to defects in genes localized to chromosome 2.

Duplication of the thumb was extensively studied by Wassel. Wassel subdivided thumb duplication on the basis of the degree of duplication. The seven types according to Wassel are listed in Table 673-5. Small finger duplication has been further subdivided into two types. Type A is a well-formed digit. Type B is a small, often underdeveloped supernumerary digit.

Table 673-5 WASSEL CLASSIFICATION OF THUMB DUPLICATION

Adapted from Wassel, HD: The results of surgery for polydactyly of the thumb. A review, Clin Orthop 125:175–193, 1969.

Thumb Hypoplasia

Hypoplasia of the thumb is a challenging condition for both the patient and the doctor. The thumb represents ∼40% of hand function. A less-than-optimal thumb can severely limit a patient’s function as he or she grows and develops. Hypoplasia of the thumb can range from being mild with slight shortening and underdeveloped musculature to complete absence of the thumb (Fig. 673-4). Radiographs are useful to help determine osseous abnormalities. The most important finding on physical exam is the presence or absence of a stable carpometacarpal (CMC) joint. This finding helps guide surgical treatment.

Figure 673-4 Congenital absence of the thumb.

Treatment

If the thumb has a stable CMC joint, reconstruction is advised. Key elements of thumb reconstruction include rebuilding the ulnar collateral ligament of the metacarpophalangeal joint, tendon transfers to aid in abduction, and procedures to deepen the web space.

If a stable CMC joint is not present or the thumb is completely absent, pollicization (surgical construction of a thumb from a finger) is the definitive treatment. Pollicization is a complex procedure rotating the index finger along its neurovascular pedicle to form a thumb. This procedure is typically performed at around 1 yr of age and may be followed by subsequent procedures to deepen the web space or augment abduction (Fig. 673-5).

Figure 673-5 Postsurgical image after pollicization.

Syndactyly

Failure of the individual digits to separate during development produces syndactyly. Syndactyly is one of the more common anomalies observed in the upper limb (Table 673-6). It is seen in 0.5 of 1,000 live births. Syndactyly can be classified as simple (skin attachments only), complicated (bone and tendon attachments), complete (fusion to the tips, including the nail), or incomplete (simple webbing).

Fingertip Injuries

Young children are fascinated with door-jambs or car doors and other tight spaces, making crush injuries to the fingertips quite common. Injury can range from a simple subungual hematoma to complete amputation of part or the entire fingertip. Radiographs are important to rule out fractures. Physeal fractures associated with nailbed injuries are open fractures with a high risk of osteomyelitis, growth arrest, and deformity if not treated promptly with formal surgical debridement and reduction. Tuft fractures involving the very distal portion of the distal phalanx are common and require little specific treatment other than that for the soft-tissue injury.

The treatment of the soft-tissue injury depends on the type of injury. For suture repairs, only absorbable sutures should be used, because suture removal from a young child’s fingertip can require sedation or general anesthesia. If a subungual hematoma exists but the nail is normal and no displaced fracture exists, the nail need not be removed for nailbed repair. If the nail is torn or avulsed, the nail should be removed, the nail bed and skin should be repaired with absorbable sutures, and the nail (or a piece of foil if the nail is absent) should be replaced under the eponychial fold to prevent scar adhesion of the eponychial fold to the nail bed that can prevent nail regrowth.

If the fingertip is completely amputated, treatment depends on the level of amputation and the age of the child. Distal amputations of skin and fat in children <2 yr of age can be replaced as a composite graft with a reasonable chance of surviving. Similar amputations in older children can heal without replacing the skin as long as no bone is exposed and the amputated area is small. A variety of coverage procedures exist for amputations through the mid-portion of the nail. Amputations at or proximal to the proximal edge of the fingernail should be referred emergently to a replant center for consideration for microvascular replantation. When referring, all amputated parts should be saved, wrapped in saline-soaked gauze, placed in a watertight bag, and then placed in ice water. Ice should never directly contact the part, because it can cause severe osmotic and thermal injury.

Trigger Thumb and Fingers

The flexor tendons for the thumb and fingers pass through fibrous tunnels made up of a series of pulleys on the volar surface of the digits. These tunnels, for reasons that are not well understood, can become tight at the most proximal or 1st annular pulley. Swelling of the underlying tendon occurs, and the tendon no longer glides under the pulley. In children, the most common digit involved is the thumb. It has classically been thought to be a congenital problem, but prospective screening studies of large numbers of neonates have failed to find a single case in a newborn child. Trauma is rarely a feature of the history, and the condition is often painless. Overall function is rarely impaired. A trigger thumb typically manifests with the inability to fully extend the thumb interphalangeal joint. A palpable nodule can be felt in the flexor pollicis longus tendon at the base of the thumb. Other conditions can mimic trigger thumb, including the thumb-in-palm deformity of cerebral palsy. Similar findings in the fingers are much less common and can be associated with inflammatory conditions such as juvenile rheumatoid arthritis.