Congenital Radioulnar Synostosis: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Congenital Radioulnar Synostosis?
A primary care doctor, such as a family doctor or pediatrician, is often first to evaluate the problem, order X-rays, and refer the patient to an orthopedic surgeon, a specialist in bones and joints. Genetic testing may involve a genetics specialist.
What it is
Congenital radioulnar synostosis is a condition a person is born with in which the two forearm bones, the radius and the ulna, are joined by bone or tough tissue. These bones normally rotate to let you turn your palm up and down; when they are fused, that motion is limited or missing.
Symptoms
The main sign is trouble turning the palm up or down. Many people keep the forearm locked in a middle position, with the palm facing the body. Daily tasks like eating with a spoon or turning a doorknob can be harder. Many people adapt by moving the shoulder and wrist more, so some never notice a problem.
Causes and who gets it
This condition happens before birth, when the forearm bones fail to separate. It can run in families or be linked to gene changes, and sometimes it appears with other conditions affecting the skeleton or development. It can also occur on its own and can affect one arm or both.
How doctors diagnose it
A doctor will ask about family history and examine arm movement. An X-ray will usually show whether the bones are joined. In young children, some bone has not hardened yet, so the fusion may be easier to see as the child grows.
Treatment
Treatment depends on how much the problem affects daily life. Many people need no treatment and live full, active lives. Physical therapy may help. Surgery can sometimes separate the fused bones, but it is complex and usually considered only when hand position makes everyday tasks very hard.
When to see a doctor
Talk to a doctor if a child cannot turn the palm up or down or holds the arm in an unusual position. Adults should seek care if the arm limits work, sports, or self-care, or if there is pain.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance; a concierge doctor usually charges more and often works alongside insurance. Either can examine the arm, order X-rays, follow the condition, and coordinate physical therapy, referring to specialists when needed.
Common questions
Can congenital radioulnar synostosis be cured?
Surgery can separate the fused bones in some cases. However, the twisting motion of the forearm often does not come back completely. Many people manage well without surgery by adapting how they move. Results vary from person to person.
Does it get worse over time?
The fusion itself does not usually change much after childhood. Some adults develop aches or discomfort in the forearm or wrist. Regular checkups can help monitor the arm over the years.
Will my child be able to play sports?
Many children with this condition play sports and do most activities with few limits. The shoulder and wrist often make up for the lost forearm rotation. A doctor can give guidance based on the child's specific situation.
Should other family members be tested?
Because the condition can run in families, a doctor may suggest genetic testing or an evaluation of siblings. This depends on the family history and whether other signs are present. A genetics specialist can help answer these questions.
Sources
- NIH Genetic and Rare Diseases Information Center - Radioulnar synostosis
- MedlinePlus - Birth Defects
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
