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HealthInfo Waitaha Canterbury

Broken forearm in children

Kikowhiti tāwhatiwhati i ngā tamariki

A diagram showing the positions of the radius, ulna and humerus in the arm.There are two bones in the forearm, the radius and the ulna. When tamariki (children) break these bones, there can be two types of breaks.

In greenstick fractures, the bones bend quite badly and partially break, but do not snap right through.

In the other type, the bones break right through and get quite badly out of line.

Symptoms of a broken forearm in children

Your tamaiti (child) will complain of pain in their arm and will not want to use it. If it's a full break, their arm may swell or look bent. If it's a greenstick fracture, their arm may look normal.

Diagnosing a broken forearm in children

If your tamaiti child complains of a sore arm after a fall and cannot or will not move their arm, it's important to see your general practice team or after-hours clinic.

The doctor or nurse will ask you about the injury. They will examine the arm and take an X-ray to find out which bone is broken and how it broke.

Treating a broken forearm in children

If the bones are still in the normal position, they will usually heal successfully with a cast that holds them in the right position (immobilisation).

The cast might need to go above the elbow to keep the bones in the right place. The plaster cast may have a cut in it at first to allow for swelling. The cut will either be joined up before your tamaiti goes home or at their first visit to the Orthopaedic Outpatients Department.

Sometimes the doctor may have to gently move the bones back into place before the splint or cast is fitted. This is called a closed reduction. If your tamaiti needs this, they will have some form of anaesthetic before this happens.

Children's bones do not need to be perfectly aligned for them to heal. They have so much growing to do that their body manages to remodel the bones over time into a straight bone.

As your tamaiti heals, they may have some X-rays to make sure the bones are staying in place.

Helping your child with a broken forearm

At first, it's important to encourage your tamaiti to keep their arm raised on pillows and to pump their fingers. This helps to decrease the swelling.

They might need simple pain medication. Give it to them regularly until they're comfortable, but never exceed the recommended dose.


At their second or third visit to the Orthopaedic Outpatients Department, the cast your tamaiti has might be changed to a lighter, coloured one. We cannot change the cast too early as this might make the broken bones move and cause some pain.

Your tamaiti can go back to school once the pain has gone and their arm is no longer swollen (about a week after the injury). It's best to keep the arm in a sling or collar and cuff to stop it being knocked while they're at school.

Written by HealthInfo clinical advisers. Last reviewed March 2022.


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Review key: HISAA-362960