CHAPTER 29

Congenital Upper Limb Differences

General Introduction

• Congenital upper limb differences (CULD) occur in approximately 27 in 10,000 live births.

• CULD may occur as an isolated finding or as a systemic condition, and it may be categorized as malformations (anatomic structures did not form normally), deformations (normally formed structures became altered), dysplasias (abnormalities of the growth process), or syndromes (Box 29-1).

• Early recognition of CULD by the pediatrician facilitates appropriate counseling, treatment, and timely referral for the infant.

• Given a concern for neurotoxicity with regard to general anesthesia in infants (based on laboratory studies on animals), surgical treatment is usually not considered until the patient is at least 1 year of age in order to minimize anesthesia-related risks.

NORMAL DEVELOPMENT OF THE UPPER LIMB

• Upper limb develops between weeks 4 and 8 of gestation. Congenital malformations occur during this period, whereas deformities and dysplasias may occur and manifest later.

• At 4 weeks’ gestation, the upper limb bud grows in a proximal-to-distal pattern controlled by apical ectodermal ridge cells at its distal end.

• Finger separation is complete by 8 weeks’ gestation.

• The hand initiates movement by 9 weeks’ gestation.

Types of CULD

TRIGGER THUMB

Introduction/Etiology/Epidemiology

• Relatively common, with incidence of 3 in 1,000 live births

• Likely acquired and not congenital, since trigger thumbs are not usually identified at birth

Box 29-1. Oberg-Manske-Tonkin Classification of Congenital Hand and Upper Limb Anomalies

Adapted from Oberg KC, Feenstra JM, Manske PR, Tonkin MA. Developmental biology and classification of congenital anomalies of the hand and upper extremity. J Hand Surg Am. 2010;35(12):2066–2076. © 2010, with permission from Elsevier.

• Etiology unknown: Different from adult trigger thumb or finger.

• One in 4 children with trigger thumb has bilateral involvement.

Signs and Symptoms

• Fixed thumb flexion deformity at interphalangeal (IP) joint; may initially “trigger,” then become fixed

• Palpable nodule known as Notta’s node is almost always present at the level of the metacarpophalangeal joint, at the entrance to the A1 pulley.

• Usually painless

Differential Diagnosis

• Congenital thumb-in-palm deformity and thumb hypoplasia

Diagnostic Considerations

• Check for triggering or fixed flexion deformity at thumb IP joint and palpable Notta’s node

• Radiographs are usually normal and are not necessary for diagnosis.

Treatment and Expected Outcomes/Prognosis

• Trigger thumb may resolve spontaneously without treatment. Splinting is rarely helpful.

• A1 pulley release is indicated for children whose locked deformity has not resolved by 2 to 3 years of age. This procedure is simple and curative, and complications are rare.

When to Refer

• When the condition has not resolved within 3 to 6 months of observation.

CAMPTODACTYLY

Introduction/Etiology/Epidemiology

• Nontraumatic, painless flexion contracture of the proximal IP (PIP) joint.

• Small finger is most commonly affected.

• Bilateral in 66% of patients

• Inherited sporadically in most cases, but there is an autosomal dominant type that has incomplete penetrance and variable expressivity. May be associated with syndromes such as arthrogryposis multiplex congenita and distal arthrogryposis.

Signs and Symptoms

• Often unnoticed and very rarely is associated with any change in function

• Typically painless with no motor or sensory deficits

• Patients present with a flexion deformity at the PIP joint, which can be flexible (passively correctable) or fixed (non-correctable).

• Distal IP and metacarpophalangeal joints are usually unaffected.

Differential Diagnosis

• Traumatic PIP contracture, clinodactyly, malunion of a fracture

Diagnostic Considerations

• Measure active and passive range of motion.

• Obtain radiographs of the involved digit to evaluate for any bony deformity.

Treatment and Expected Outcomes/Prognosis

• Few patients require surgery. Stretching and splinting of the contracture is usually effective.

• Nighttime static splinting and daytime dynamic splinting can be used.

• Surgical release is considered when the trigger thumb persists despite the patient diligently splinting.

When to Refer

• Refer children with a syndrome as well as those for whom conservative treatment is unsuccessful or whose deformity worsens.

CLINODACTYLY

Introduction/Etiology/Epidemiology

• Radioulnar deviation of a digit, usually caused by malformation of the middle phalanx (ie, delta phalanx, also called longitudinal epiphyseal bracket)

• Small finger is most commonly affected.

• Usually inherited sporadically, but there is an autosomal dominant type that has variable penetrance.

Signs and Symptoms

• Presents with a radioulnar curvature to the digit without a history of trauma

• Typically painless with no motor or sensory deficits

Differential Diagnosis

• Traumatic PIP contracture, camptodactyly, malunion of a fracture

Diagnostic Considerations

• Measure the degree of deformity.

• Obtain radiographs of the involved digit to evaluate for a longitudinal epiphyseal bracket.

Treatment and Expected Outcomes/Prognosis

• If there is no epiphyseal bracket, the deformity will be nonprogressive and highly unlikely to require surgical intervention to improve function.

When to Refer

• Refer to a pediatric hand surgeon on diagnosis.

CONSTRICTION BAND SYNDROME (AMNIOTIC BAND SYNDROME)

Introduction/Etiology/Epidemiology

• Incidence is 1 in 1,200 to 1 in 15,000 live births

• Not inheritable

• Cause is unknown; may be due to germline developmental abnormality, mechanical disruption of development, or embryonic vascular disruption associated with fetal exposure to toxin; historical eponyms have been abandoned

• Any or multiple limbs may be involved.

• Associated with clubfoot and craniofacial clefts; 80% have hand and/or finger manifestations such as amputation or syndactyly

Signs and Symptoms

• Usually asymptomatic; tips of digits may become painful during growth spurts if bone outgrows soft tissue

• Examination demonstrates normal anatomy proximal to the constriction ring

• Syndactyly is common, and nonadjacent syndactyly is pathognomonic. Nail deformities are also common.

• Constriction bands are commonly perpendicular to the long axis of the extremity.

Differential Diagnosis

• Transverse deficiency, symbrachydactyly, central ray deficiency

Diagnostic Considerations

• The diagnosis is made on physical examination.

• Multiple bands, nonadjacent syndactyly, and sinuses between digits affected by syndactyly are pathognomonic.

Treatment and Expected Outcomes/Prognosis

• If multiple digit involvement, consider simple finger separation

• Severe lymphedema can occur, and vascular supply of the digit or extremity may be compromised. In these cases, the deep circumferential rings should be released with excision or z-plasty.

When to Refer

• Refer to a pediatric orthopaedic surgeon and/or pediatric hand surgeon on diagnosis.

SPRENGEL DEFORMITY

Introduction/Etiology/Epidemiology

• Congenital elevation of the scapula

• Caused by arrest of the typical caudal migration of the scapula from the embryonic limb bud to the thorax; the superior border of the scapula normally lies at the level of the seventh vertebra, with its inferior border at the sixth rib.

• In 30% of cases, the scapula is attached to the cervical spine by cartilage, fibrous tissue, or an omovertebral bone further limiting scapulothoracic motion.

• Poses functional and cosmetic problems

• Bilateral in 10% to 30% of cases

• Males and females are equally affected.

• Associated conditions and anomalies

— Anomalies of the clavicles, vertebrae, ribs, and shoulder musculature

— Congenital scoliosis

— Sprengel deformity is present in 35% of children with Klippel-Feil syndrome (a disorder of segmentation of the cervical vertebrae).

— Possible renal or pulmonary disorders.

Signs and Symptoms

• Shoulder asymmetry and limited shoulder abduction due to loss of scapulothoracic motion and glenoid malpositioning

• Thickened neck on the affected side

• Possible neck or shoulder pain

• Scapula is elevated and adducted, with its superior angle often palpable at base of neck

• In mild cases, the condition may not be apparent until the child is older.

Differential Diagnosis

• Other causes of limited shoulder abduction include abnormal or weakened periscapular muscles.

• Other causes of shoulder and neck asymmetry include torticollis and scoliosis.

Diagnostic Considerations

• Diagnosis is confirmed with anteroposterior (AP) radiographs of the chest and shoulders.

• Cervical and thoracic spine radiographs are obtained to evaluate for associated anomalies.

Treatment and Expected Outcomes/Prognosis

• Computed tomography and magnetic resonance imaging are useful for surgical planning.

• Mild deformities

— Cause minimal functional impairment

— Physical therapy has no therapeutic value.

• More severe deformities

— Range of motion of the shoulder is limited, preventing abduction beyond 90 degrees.

— Surgery may be indicated for children with marked functional deficits and cosmetic deformity.

— Best surgical results are obtained when performed before 8 years of age.

When to Refer

• Refer patients with functional deficits, cosmetic deformity, or associated musculoskeletal anomalies to a pediatric orthopaedic surgeon.

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