Arthrogryposis

CHAPTER 67

Arthrogryposis

Introduction/Etiology/Epidemiology

• The term arthrogryposis is derived from the Greek, meaning “curved joint.”

• It refers to a group of more than 400 syndromes in which multiple joint contractures are present at birth.

— The most recognizable of these syndromes is amyoplasia.

— All are associated with decreased fetal movement, which results in multiple joint contractures, which can be diagnosed on prenatal ultrasonography.

— There are numerous primary etiologies.

• The incidence of arthrogryposis is 1 in 3,000 live births.

• The incidence of amyoplasia (most common form) is 1 in 10,000 live births.

• About half of the conditions associated with arthrogryposis have a syndromic or genetic abnormality.

— Determining the cause of each patient’s arthrogryposis is important to predict risk of additional children born to the same parents being affected.

— It is also important to determine if unaffected siblings are carriers of the condition.

— Amyoplasia is thought to be nongenetic.

• When arthrogryposis is seen along with an intellectual disability, a genetic evaluation should be performed.

— Microarray

— Exome studies

• Clinical classification is based on the system or systems involved.

— Primary limb involvement (eg, amyoplasia, distal arthrogryposis)

— Musculoskeletal plus other system involvement

— Musculoskeletal plus other system dysfunction, intellectual disability, or lethality

• The overall cause of fetal akinesia may be

— Intrinsic conditions (eg, neuromuscular disease)

— Environmental conditions (ie, maternal illness or exposures)

— Extrinsic conditions (eg, lack of intrauterine space)

• The etiologic process may be neuropathic (myelin defects, myopathies), metabolic disorders, skeletal dysplasias, space limitations, maternal conditions, or intrauterine vascular compromise

• Presentations

— Amyoplasia

— Distal arthrogryposis

— Everything else (pterygium syndromes, X-linked syndromes, teratologic conditions, maternal illness, intellectual disability, fetal akinesia deformation sequence, lethal conditions)

Signs and Symptoms

• Pregnancy history typically reveals decreased fetal movements.

• Loss of skin creases across joints

• Dimples may be present over the extensor surfaces of involved joints.

• Severe muscle atrophy and a decrease in subcutaneous fat

• Joint motion is restricted, and there is a firm inelastic block with passive motion.

• The shoulders are internally rotated and adducted.

• The elbows are extended with the forearms pronated.

• The wrist and fingers are flexed.

• The fingers are thin and tapered.

• Foot deformities are present in 90% of patients.

— Clubfoot is the most common, especially in amyoplasia

— Vertical talus is also seen.

• Seventy percent have knee contractures, both flexion and extension.

• Forty percent have hip deformities including subluxation, frank dislocation, and contracture.

• The occurrence of scoliosis in patients with amyoplasia is common.

Differential Diagnosis

• Bilateral brachial plexus palsy

• Bony fusion

— Symphalangism (ie, fusion of phalanges)

— Coalition (ie, fusion of the carpals and tarsal bones)

— Synostosis (ie, fusion of long bones)

• Absence of dermal ridges

• Absence of distal interphalangeal joint creases

• Amniotic bands

• Antecubital webbing

• Camptodactyly

• Coalition

• Humeroradial synostosis

• Familial impaired pronation and supination of forearm

• Liebenberg syndrome

• Nail-patella syndrome

• Nievergelt-Pearlman syndrome

• Poland anomaly

• Tel Hashomer camptodactyly

• Trismus-pseudocamptodactyly syndrome

Diagnostic Considerations

• Diagnosis is established based on history and physical examination and consultation with specialists in genetics and/or neurology as indicated.

• Electromyograms and muscle biopsies are of little value, although these tests may help to differentiate between myopathic and neuropathic forms.

• Prenatal ultrasonography may suggest the diagnosis when it shows decreased or absent fetal movement in association with oligohydramnios and joint contractures.

Treatment

• Management requires a multidisciplinary team including a pediatric neurologist, pediatric orthopaedic surgeon, rehabilitation physician, geneticist, occupational therapist, physical therapist, and orthotist.

• The goal of treatment is to optimize function and independence.

• In the lower extremities, the goal is alignment and stability for ambulation.

• In the newborn, a program of early physical therapy and/or occupational therapy, as well as stretching and bracing, can be successful in improving passive range of motion.

— Careful attention to the birth process is important to make sure there are no long bone fractures before beginning a stretching program.

— Serial stretching casts, applied on a weekly basis, are initiated soon after birth.

— A percutaneous Achilles tenotomy can also be done, as in the Ponseti technique.

• Foot deformities are very difficult to correct and may require surgery (extensive posteromedial release) in addition to the Ponseti method of casting.

— The surgical correction is done at about 1 year of age.

— Because the recurrence rate is high, long-term bracing is required postoperatively.

— Talectomy is reserved for severe recurrent deformities.

• Knee contractures

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