What is Arthrogryposis Multiplex Congenita?

• AMC name derived from Greek means curved or hooked joint. It is a condition in which a child is born with multiple joint (hand, feet, knee, ankle, elbow, hip, shoulder & finger) contractures, stiffness, muscular wasting & weakness in the body. Lack of joint mobility is often accompanied by fibrous ankyloses.
• It is a non-progressive condition.
• This problem occurs because of many reasons.
• This is a rare disorder, occurs in 1 out of 3000 live births.
• It equally affect male and female both
• These children will have normal speech & normal intelligence.
• As many as 150 syndromes have similar features with arthrogryposis
• Arthrogryposis is detected at birth or in utero using ultrasound

What are the Causes For AMC? 

• There is no single cause of this complex problem.
• It is common belief that that disease begins in the first trimester of pregnancy.
• Several theories have given to the causes of AMC:
• One essential factor which causes this problem is foetal akinesia, in which foetal movement in the mother’s uterus decreases. If it persists for a long duration, then joint stiffness and muscle contracture develop.
• It can be related to multiple factor including genetic & environment one.
• Most of the time, causes are not clear, but in 30% of cases, you can find sporadic genetic causes.
• But the familial transmission is rare.
• Extrinsic (outside factors): Insufficient room in uterus; low amniotic fluid or abnormally shaped uterus; maternal infection, drugs, trauma etc.
• Intrinsic (within child): Neurological (problem in spinal cord or brain; Connective tissue disorders (tendons, ligaments, bones or joint lining).

Subgroup of AMC:

• Neurological diseases (brain, spine, or peripheral nerve)
• Connective tissue defects (diastrophic dysplasia),
• Muscle abnormalities (muscular dystrophies or mitochondrial abnormalities),
• Maternal diseases (diabetes mellitus, multiple sclerosis, myasthenia gravis, infection, drugs, or trauma)
• Space limitations within uterus (oligohydramnios, fibroids, uterine malformations, or multiple pregnancy),
• Intrauterine or foetal vascular compromise (impaired normal development of nerves, or anterior horn cell death)

Classification of AMC

• Amyoplasia is most common (40%) classical type.
• Second type is distal arthrogryposis syndrome
• Third type is Syndromic

Arthrogryposis Multiplex Congenita Sign & Symptoms?

The new born child will present with signs & symptoms of multiple joint deformity, contracture, dislocation etc.

Classic arthrogryposis (Amyoplasia):

• Bright eyed intelligent children, normal to above average cognition
• Sensation is usually normal
• Classic arthrogryposis is characterized by symmetric involvement of all limbs in 60–92% of patients.
• The arms & legs are often thin & atrophic, lack of flexion creases at joints
• Involved extremities are fusiform or cylindrical in shape, with thin subcutaneous tissue & absent skin creases
• Deformities are usually symmetrical & severity increases distally, with hands & feet typically most deformed
• Typically all four extremities are involved, but there are some with just upper or lower involvement.
• Shoulder Internal rotation contracture & inefficient deltoid muscle
• Elbow Extension-pronation contracture
• Wrist flexion contracture & ulnar deviation
• Hand Fingers-fixed flexion, thumb in palm
• Hip Flexed, abducted, and externally rotated
• Knee Flexion deformity
• Clubfoot

Distal arthrogryposis:

• Distal arthrogryposis syndromes are often hereditary
• Muscle weakness presents in nearly 40 % of patients
• Contractures limited mainly to distal portions of limbs, i.e. to wrists, hands, ankles & foot. Contractures of other joints are low-degree / absent altogether syndromes involve more peripheral joints (i.e.-Type I), can have more extensive hand & feet involvement.
• Uncommon problems include scoliosis, respiratory issues, facial, jaw variations & abdominal hernias.
• Mental retardation/CNS involvement is found in approximately 25 % of individuals with AMC

How to Diagnosis the AMC? 

• There is no prenatal diagnostic tool to test for this condition.
• During a routine ultrasound, abnormal limbs may be noted, but no definitive cause can be ascertained until further tests can be run.
• A full history & general exam of clinical findings are mainstay of diagnosis.
• Photography to document extent of deformities to assess progress during treatment.
• Diagnosis of Arthrogryposis Multiplex Congenita is made by clinical examination by a paediatric orthopaedic surgeon or paediatrician after birth
• Genetic analysis can help only in identifying the cause of this problem.

How AMC is treated?

• Most arthrogryposis congenital children will have normal speech and a good IQ.
• There is no absolute cure for this problem.
• The different methodologies of treatment can improve the quality of life.
• Prognosis depends upon the severity of the problem and area of involvement.

Treatment modalities:

Physical & occupational therapy:

• With the help of physical and occupational therapy joint mobility, power and balance can be improved.
• It may be required for a longer duration.
• The child may need some orthopedic intervention intermittently.
• Stretching & joint mobilization exercise should be very gentle but this should be continued for long.
• Gait training, pelvis balancing is must for getting good outcome.
• Brace is required to support the limb for standing & walking.

Orthopedic intervention:

• Most of the deformities and contractures in AMC are very rigid and stiff, so they need repeated manipulation plaster or tapping.
• These children require more number of plaster in comparison with other children with similar problem.
• Some joint deformity which is very rigid, may require surgery.
• A situations like congenital dislocation of the knee & congenital hip dislocation will require surgery.
• Club foot require manipulation and plaster application.
• Careful planning and execution of proper surgery is a must.
• After surgery, a brace and therapy for a longer duration are required. All this planning should be done by a paediatric-orthopaedic surgeon, who has sufficient experience in treating this type of problem.

Prognosis:

• Life span of affected people depends on severity of syndrome & associated malformations but is often normal.
• They have nearly normal IQ
• They can do all non-strenuous activity.
• They can read, write and lead a professional life.

Reference Links :

• https://en.wikipedia.org/wiki/Arthrogryposis
• https://rarediseases.info.nih.gov/diseases/777/arthrogryposis-multiplex-congenita/
• https://emedicine.medscape.com/article/941917-treatment
• https://www.jposna.org/ojs/index.php/jposna/article/view/277/219