Radioulnar synostosis

If your baby was born with radioulnar synostosis, we know that you and your family are concerned. So, please know that at Children’s Hospital Boston, we will approach your child’s treatment and care with sensitivity and support—for your child and your whole family.

Radioulnar synostosis is usually congenital (something your child was born with); but it may also occur after a forearm fracture or trauma. Please note that these pages discuss the congenital form of the condition.

• If your child has radioulnar synostosis, it means that she has an abnormal bony or soft tissue connection between the two bones of her forearm—the radius (forearm bone on the (thumb) side) and ulna (forearm bone on the (little finger) side).
   
• “Synostosis” means a union or fusion of bones that are usually distinct from each other—in this case, the radius and ulna near the elbow.
   
• Signs and symptoms of your child’s condition can range from a minor to a major limitation in his/her ability to rotate his/her arm from a pronated (palms down) position to a supinated (palms up) position. She may also carry her elbow at an abnormal angle or have a shortened forearm.
   
• The end of the radius bone closest to the elbow (radial head) may be, or may become, dislocated.
   
• Diagnosis is usually confirmed by a physical exam, x-raysand/or CT scans.
   
• Children whose forearms lie in functional positions may never need surgery. Children who have the problem in both arms, and/or whose forearms are fixed in a position that limits their ability to use their arm, may benefit from surgery.
   
• Children with mild to moderate cases often compensate for their limited arm-rotation by wrist and shoulder motions.
   
• Radioulnar synostosis can occur:
  • by itself (in isolation)
  • in association with other skeletal abnormalities (about one-third of the time)
  • in association with problems of the heart, kidneys, nervous system or gastrointestinal system
  • in association with certain genetic syndromes, such as Holt-Oram syndrome (also called hand-heart syndrome) and fetal alcohol syndrome

• The condition affects both of a child’s arms about 60 percent of the time.

• The average age at diagnosis is about 6 years old.

• Boys and girls are equally affected.

• The condition isn’t usually painful for a baby. But if left untreated or undiagnosed, teens may begin experiencing pain if the end of the radius (radial head) becomes dislocated.

How Children’s Hospital Boston approaches radioulnar synostosis

You can have peace of mind knowing that the skilled experts in our Orthopedic Center’s Hand and Orthopedic Upper Extremity Program have treated thousands of babies and children with hand problems, ranging from the routine to the highly complex. So we can provide your child with expert diagnosis, treatment and care—as well as the benefits of some of the most advanced clinical and scientific research in the world.

Our Orthopedic Center is nationally known as the preeminent center for the care of children and young adults with a wide range of developmental, congenital, neuromuscular, sports related, traumatic and post-traumatic problems of the musculoskeletal system.

Radioulnar synostosis: Reviewed by Donald Bae, MD
© Children’s Hospital Boston, 2011