Overview

Arthrogryposis, medically known as arthrogryposis multiplex congenita (AMC), is a rare congenital condition characterized by joint contractures present at birth. This means that some joints are stiff or immobile and may be fixed in a bent or straightened position. Arthrogryposis is not a specific diagnosis but rather a clinical feature of many different conditions. It affects multiple joints, most commonly in the arms and legs, and can vary in severity from mild joint stiffness to severe deformities involving multiple parts of the body. Early diagnosis and therapy are essential to improve mobility and independence.

Causes

The underlying cause of arthrogryposis is reduced fetal movement (fetal akinesia) during development, which leads to abnormal joint formation and stiffness. Causes can be divided into several categories:

• Neurological causes: Problems in the brain, spinal cord, or peripheral nerves can affect muscle movement.
• Muscular causes: Genetic or developmental disorders affecting muscle growth and function.
• Connective tissue abnormalities: Disorders that cause abnormal development of tendons, bones, or joints.
• Maternal factors: Uterine abnormalities, low amniotic fluid (oligohydramnios), or maternal infections during pregnancy.
• Genetic syndromes: Arthrogryposis may be a feature of several genetic syndromes inherited in autosomal dominant, autosomal recessive, or X-linked patterns.

Symptoms

Symptoms of arthrogryposis vary depending on the type and severity of the condition, but common features include:

• Joint contractures: Limited movement in joints, especially in the shoulders, elbows, wrists, hips, knees, and ankles.
• Abnormal joint positioning: Joints may be fixed in flexed or extended positions, causing deformities.
• Muscle weakness: Underdeveloped or weak muscles surrounding affected joints.
• Thin or absent muscle tissue: Reduced muscle mass is often visible in affected limbs.
• Webbing of skin: Extra skin may be present across joints (pterygium) due to lack of movement.
• Facial features: Some children may have a small jaw or high-arched palate depending on the subtype.
• Motor delays: Developmental delays in crawling, standing, and walking are common due to restricted mobility.

Diagnosis

Diagnosing arthrogryposis involves clinical examination and supportive tests to determine the extent and cause of joint contractures:

• Prenatal detection: Ultrasounds during pregnancy may show decreased fetal movement or abnormal joint positioning.
• Physical examination: Identification of joint stiffness, muscle weakness, and overall physical assessment after birth.
• Imaging studies: X-rays and MRI can help assess joint and muscle structures.
• Genetic testing: May identify underlying syndromes or specific gene mutations linked to arthrogryposis.
• Electromyography (EMG): Tests to assess nerve and muscle function.
• Muscle biopsy: Occasionally performed to examine muscle tissue abnormalities.

Treatment

Treatment for arthrogryposis focuses on improving joint mobility, muscle strength, and functional independence. Early and ongoing treatment improves long-term outcomes:

• Physical therapy: Daily stretching and strengthening exercises to improve flexibility and prevent further joint stiffness.
• Occupational therapy: Helps children develop skills necessary for daily activities and independence.
• Splinting and bracing: Use of orthotic devices to maintain joint positioning and assist movement.
• Surgical interventions: Procedures such as tendon release, joint correction, or osteotomies may be performed to improve function.
• Assistive devices: Walkers, wheelchairs, or adaptive equipment may be used depending on severity.
• Multidisciplinary care: Collaboration between pediatricians, orthopedists, neurologists, and rehabilitation specialists is essential.

Prognosis

The prognosis for children with arthrogryposis depends on the type and severity of the condition. Many individuals achieve improved mobility and functional independence with early intervention, physical therapy, and corrective surgery. Intelligence is typically normal in most forms of arthrogryposis. While joint contractures are permanent, many affected individuals can lead active, productive lives. Severe cases may require long-term support, but early comprehensive care significantly improves quality of life and physical capabilities.