Arthrogryposis Explained: Why Some Babies Are Born With Stiff or Frozen Joints and How Therapy Changes Their Lives

4 days ago

10 min read

Updated: 2 days ago

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026

Editorial note: This article is for general education only. It is not medical advice, a diagnosis, or a treatment plan. Arthrogryposis requires evaluation by pediatric specialists — typically orthopedists, neurologists, geneticists, and physical therapists. If your child has been diagnosed with or is suspected of having arthrogryposis, work with your care team on an individualized plan. Nothing in this article suggests that a parent could have done anything differently to prevent it.

TL;DR

Arthrogryposis (arthrogryposis multiplex congenita, AMC) is not one disease but a pattern present at birth in which two or more joints are stiff, curved, or frozen in place due to contractures — permanent tightening of muscles, skin, and tendons. It occurs in about 1 in 3,000 live births (roughly 8.5 per 100,000) and appears as a feature of more than 300 different conditions, with over 400 genes implicated. The most common form, amyoplasia, affects the limbs but leaves intelligence and organs normal. Arthrogryposis is not progressive — it does not get worse — and with physical therapy, casting, and sometimes surgery, the majority of children grow up to be independent adults with a normal life expectancy.

Quick Answer: What Is Arthrogryposis?

Arthrogryposis (arthrogryposis multiplex congenita, AMC) is a descriptive term for the condition of being born with two or more joint contractures — joints that are stiff, curved, or frozen in place because of permanently tightened muscles, tendons, and skin. It occurs in about 1 in 3,000 live births, is most often caused by limited fetal movement during pregnancy, and is not progressive. Treatment centers on physical therapy, casting, stretching, and sometimes surgery, and most children with the most common form (amyoplasia) become independent adults with a normal life expectancy [1] [2] [7].

What Is Arthrogryposis (Arthrogryposis Multiplex Congenita)?

Arthrogryposis (arthrogryposis multiplex congenita, AMC) is not a single diagnosis. It is a characteristic seen in more than 300 different disorders — including muscular dystrophy and trisomy 18 (Edwards syndrome) — that describes what happens when a baby is born with more than one contracture at birth [1].

A contracture is a congenital anomaly in which the muscles, skin, and tendons around a joint permanently tighten, making the joint short and stiff. The word itself describes the effect: "arthro" means joint, and "gryposis" means crooking [1].

Children with arthrogryposis are born with joints that are difficult to move — joints that may be fixed in place, curved, or straight but frozen. Affected babies often show a recognizable set of features [1]:

Feature	Description
Shoulders	Sloped shoulders rotated toward the center of the body [1]
Elbows	Extended (straightened) elbows [1]
Hands	Curled wrists and fingers [1]
Hips	Dislocated hips [1]
Knees	Extended (straightened) knees [1]
Feet	Feet pointed downward and inward [1]
Spine	Spine curved sideways [1]

How Common Is Arthrogryposis?

Arthrogryposis is uncommon but not vanishingly rare. It occurs in 1 in 3,000 live births [1]. A large multinational study covering 8.9 million births across 24 European congenital anomaly registries found a prevalence of 8.5 per 100,000 births (757 cases), with 67% of cases resulting in live birth, 26% ending in termination for fetal anomaly, and 7% in fetal death [4]. Other sources give a range of 1 in 3,000 to 1 in 5,000 births [9].

Measure	Estimate	Evidence
Live births affected	1 in 3,000	Cleveland Clinic [1]
Multinational registry prevalence	8.5 per 100,000 births	EUROCAT study [4]
General range	1 in 3,000–5,000 births	J Clin Ultrasound, 2025 [9]
True amyoplasia (most common type)	1 in 10,000 live births	Nationwide Children's [5]
Amyoplasia share of live cases	About one-third	JPOSNA, 2021 [6]

It is worth understanding why some estimates differ. The "1 in 3,000" figure counts all arthrogryposis presentations, while true amyoplasia — the classic and most common type — occurs in about 1 in 10,000 live births, accounting for roughly one-third of live cases [5] [6].

Is Arthrogryposis Genetic or Hereditary?

Arthrogryposis is congenital, meaning it begins before birth. In most cases, the exact underlying cause is unclear [1]. But genetics play an important role: experts have identified more than 400 altered (mutated) genes that can affect arthrogryposis, and the condition is linked to over 35 genetic disorders [1]. Some forms run in families, while others — including amyoplasia — are typically sporadic, appearing in families with no history of the condition.

What's the Difference Between Arthrogryposis and an Isolated Contracture?

The distinction is one of scope. Isolated congenital contractures happen in only one area of the body. A well-known example is clubfoot [1]. Arthrogryposis, by definition, involves two or more areas — multiple joints stiff or frozen at birth [1].

Condition	Scope	Example
Isolated congenital contracture	One area of the body [1]	Clubfoot [1]
Arthrogryposis (AMC)	Two or more joints/areas [1]	Multiple limb joints stiff at birth [1]

What Are the Types of Arthrogryposis?

Two major types account for most cases:

Type	What's affected	Key notes
Amyoplasia	Contractures in the limbs [1]	The most common type — about one-third of live cases; usually sporadic (not inherited); internal organs and intelligence typically normal [1] [6]
Distal arthrogryposis	Hands and feet, sparing larger joints [1]	Often genetic; affects the body's "distal" (far) ends [1]

Beyond these two, arthrogryposis appears as a feature of hundreds of syndromes, which is why finding (or ruling out) an underlying cause is central to diagnosis [1].

What Causes Arthrogryposis?

In most cases, the exact underlying cause is unclear. The most common possible causes cluster around anything that restricts fetal movement or affects the nerves and muscles that move joints [1]:

Possible cause	How it leads to contractures
Limited fetal movement	Insufficient amniotic fluid, twins in one uterus, or an unusually shaped uterus prevent joint movement; without movement, excess tissue forms around joints [1]
Maternal disorder	Conditions in the pregnant person such as multiple sclerosis [1]
Genetic disorder	Inherited muscle diseases such as muscular dystrophy [1]
Central nervous system disease	Moebius syndrome, spina bifida (meningomyelocele) [1]
Neuromuscular disease	Myasthenia gravis [1]
Connective tissue disease	Skeletal dysplasias such as metatropic dwarfism [1]

In some cases, the cause is likely a combination of genetic and environmental factors [1]. The unifying idea is simple: joints need movement in the womb to develop normally — when movement is restricted, joints freeze in place [1] [3].

What Are the Symptoms of Arthrogryposis?

Symptoms vary from person to person — even within the same family, one child's presentation may be milder or more severe than another's [1].

Universal symptoms — present in everyone with arthrogryposis [1]:

Symptom	Details
Joint movement limits	Limited ability to move small and large joints, up to complete inability to move them [1]
Underdeveloped muscles	Hypoplastic (underdeveloped) muscles [1]
Limb appearance	Soft, tube-shaped limbs [1]
Soft tissue webbing	Webbing over joints that keeps joints from moving [1]

Symptoms most people experience [1]:

Symptom	Details
Fragile long bones	Extra slender and fragile long bones in the arms and legs [1]
Undescended testes	Cryptorchidism in males [1]

Symptoms a smaller percentage experience [1]: dislocated hips, elbows, or knees; structural problems of the brain and spine; or functional problems of the central nervous system.

The pattern of which joints are affected is consistent: leg joints are affected more than any others, with arms next in line. Also commonly affected are the shoulders, knees, elbows, ankles, fingers, wrists, toes, hips, and jaw [1].

One reassuring note about the most common type: children with amyoplasia usually have no internal organ or cognitive issues, though about 10% have abdominal problems such as gastroschisis (a hole in the abdominal wall) or intestinal atresia (a blocked intestine) [1].

How Is Arthrogryposis Diagnosed?

Diagnosis can begin before birth. Routine ultrasounds can reveal atypical limbs suggesting arthrogryposis, and providers usually discover the contractures during the second trimester of pregnancy. Genetic counseling may be recommended, along with prenatal genetic testing such as chorionic villus sampling (CVS) or amniocentesis [1].

Diagnosis can also happen after birth, through physical observation combined with testing [1]:

Test	What it checks
Nerve conduction studies	How quickly nerves transport electrical impulses [1]
Electromyography (EMG)	Electrical activity in muscles [1]
Muscle biopsy	A small muscle sample studied under a microscope [1]
Genome sequencing	Identifies altered genes [1]
Blood tests	Gene and chromosome abnormalities [1]
CGH array	Detects chromosome changes [1]
Microarray	Analyzes thousands of genes at once [1]
Exome studies	Identifies gene variations [1]
Ultrasound	Imaging of limbs and joints [1]

Once providers identify a possible underlying cause, they build an individualized treatment plan with the family [1].

One sobering data point: prenatal ultrasound catches only a minority of cases. A 2024 study found the antenatal detection rate was just 37% — most babies with arthrogryposis are not identified before birth, even with routine prenatal care [8]. In that same study, 53% of mothers later recalled decreased fetal movement during pregnancy, a clue that is easy to miss [8].

How Is Arthrogryposis Treated?

There is no cure for arthrogryposis, but treatments can substantially improve a child's function and quality of life. Because possible causes differ for every child, treatment is individualized [1].

Treatment	How it helps
Casting	Moves stiff joints gradually [1]
Physical therapy	Improves joint motion and prevents muscle atrophy (wasting) [1]
Joint manipulation	A therapy in which joints are gently moved [1]
Stretching exercises	Increases flexibility and range of motion [1]
Surgery	On ankles, hips, knees, wrists, or elbows to increase range of motion — rare; detaches bones from tissues that block movement and encourages muscles to flex [1]

Providers recommend a multidisciplinary approach: a pediatrician, orthopaedist, neurologist, medical geneticist, rehabilitation physician, and physical therapist may all be involved [1]. Most children need physical therapy well into their teenage years, with home exercises taught by the therapist [1].

What Is the Outlook for Children With Arthrogryposis?

The long-term outlook depends on three things: the severity of the arthrogryposis, the underlying cause, and how well the child responds to therapy [1].

The central facts about prognosis are encouraging [1] [5] [6]:

Outlook question	Answer
Does it go away?	No — but treatments improve quality of life [1]
Does it get worse?	No — arthrogryposis is not progressive, though the underlying condition might be [1]
Can children become independent?	Yes — the majority grow up to be independent adults, leading lives similar to people without arthrogryposis [1]
Life expectancy (classic amyoplasia)	Normal for most survivors [6]
20-year survival (classic amyoplasia)	94% [7]

The headline perinatal mortality figure of about 32.5% from the multinational registry applies across all AMC — but that average is driven by the rare, severe syndromic forms (such as lethal fetal akinesia syndromes and trisomy 18). For children with the classic, non-syndromic form (amyoplasia), life expectancy is normal and 20-year survival is 94% [6] [7].

Can Arthrogryposis Be Prevented?

No. Preventing arthrogryposis is out of any parent's hands. There is nothing a parent could have done to reduce a child's risk of arthrogryposis [1]. This matters emotionally as well as medically: a diagnosis like this can trigger guilt, and the medical consensus is that there is nothing to feel guilty about [1].

Key Takeaways

Arthrogryposis (AMC) is a pattern of two or more joint contractures present at birth — stiff, curved, or frozen joints caused by permanent tightening of muscles, tendons, and skin. It affects about 1 in 3,000 live births (8.5 per 100,000 in multinational registry data), involves over 400 genes and more than 300 conditions, and most often traces to limited fetal movement in the womb. The most common type, amyoplasia (~1 in 10,000 live births, about one-third of live cases), spares the brain and internal organs. It is not progressive — it does not worsen — but it does not go away. Treatment is individualized and multidisciplinary: physical therapy, casting, stretching, joint manipulation, and rarely surgery. With early, consistent intervention, the majority of children grow up to be independent adults, classic amyoplasia carries a 94% 20-year survival rate and a normal life expectancy, and nothing a parent did or didn't do caused it. If your baby has been diagnosed with or suspected of having arthrogryposis, ask your care team about early physical therapy, the specific type involved, and whether genetic testing can identify the cause — early intervention is the single biggest lever for long-term independence.

Frequently Asked Questions

Can arthrogryposis be cured?

No, but it is highly manageable. There is no cure, yet physical therapy, casting, stretching, and occasionally surgery can improve joint movement enough that most children — especially with classic amyoplasia — grow up to be independent adults with a normal life expectancy [1] [6] [7].

Is arthrogryposis the same as cerebral palsy?

No. Cerebral palsy results from brain injury, usually around birth. Arthrogryposis means multiple joint contractures are present at birth, and in most cases the brain is unaffected. Some underlying causes overlap (neuromuscular and central nervous system conditions), but the two are distinct [1].

How common is arthrogryposis?

About 1 in 3,000 live births, or 8.5 per 100,000 births in a study of nearly 9 million births across 24 European registries. The most common specific type, true amyoplasia, occurs in about 1 in 10,000 live births [1] [4] [5].

Why does it happen? Can anything cause it during pregnancy?

In most cases the exact cause is unknown, but the leading explanation is limited fetal movement in the womb — from low amniotic fluid, twins sharing space, or an unusually shaped uterus. Genetic mutations (over 400 identified), neuromuscular and central nervous system conditions, and maternal disorders can also be involved. Nothing a parent does causes it [1] [3].

Is it genetic — will my next child have it?

Sometimes. Over 400 altered genes and 35+ genetic disorders are linked to arthrogryposis, so some forms run in families. However, the most common form, amyoplasia, is usually sporadic. A medical geneticist can help assess recurrence risk for your family [1].

Can it be detected before birth?

Sometimes, but often not. Routine second-trimester ultrasounds can show atypical limbs, and prenatal testing (CVS or amniocentesis) can check for genetic causes. However, only about 37% of cases are detected before birth in recent studies — most babies are diagnosed after delivery [1] [8].

Does arthrogryposis get worse over time?

No. Arthrogryposis is not progressive — the contractures themselves do not worsen. However, the underlying condition that caused it might be progressive, which is why identifying the cause matters [1].

Will my child walk and live independently?

In most cases, yes. The majority of children with arthrogryposis become independent adults who lead lives similar to people without the condition. For classic amyoplasia, 20-year survival is 94% and life expectancy is normal. Early, sustained physical therapy is the biggest factor in long-term independence [1] [6] [7].