Knee Fracture, Child

A knee fracture is a break in any of the bones of the lower part of the thigh bone, the upper part of the bones of the lower leg, or of the kneecap. When the bones no longer meet the way they are supposed to it is called a dislocation. Sometimes there can be a dislocation along with fractures.

ExitCare ImageThe bones of a child are more flexible than an adult. The bones sometimes crack like green branches. These are called green stick fractures. Other times the bones just buckle slightly. When this happens, there may not be a clear fracture line, just a slightly raised area on the outside of the bone. Another difference from adult bones is that a child's bones are still growing. Bones grow from an area near their ends called the growth plate. Fractures in the growth plate can be difficult to see on an x-ray and may require special x-rays or other tests.


Symptoms may include pain, swelling, inability to bend the knee, deformity of the knee, and inability to walk.


This problem is usually diagnosed with x-ray studies. Special studies are sometimes done if a fracture is suspected but not seen on ordinary x-rays. If vessels around the knee are injured, special tests may be done to see what the damage is.


  • The leg is usually splinted for the first couple of days to allow for swelling. After the swelling is down, a cast is put on. Sometimes a cast is put on right away with the sides of the cast cut to allow the knee to swell. If the bones are in place, this may be all that is needed.

  • If the bones are out of place, medications for pain are given to allow them to be put back in place. If they are seriously out of place, surgery may be needed to hold the pieces or breaks in place using wires, pins, screws or metal plates.

  • Generally most fractures will heal in 4 to 6 weeks.


  • Your child should use their crutches as directed. Help them to know that not doing so will hurt their knee.

  • To lessen swelling, the injured leg should be elevated while the child is sitting or lying down.

  • Place ice over the cast or splint on the injured area for 15-20 minutes 03-04 times per day during your child's waking hours. Put the ice in a plastic bag and place a thin towel between the bag of ice and the cast.

  • If your child has a plaster or fiberglass cast:

  • They should not try to scratch the skin under the cast using sharp or pointed objects.

  • Check the skin around the cast every day. Put lotion on any red or sore areas.

  • Keep your child's cast dry and clean.

  • If your child has a plaster splint:

  • Your child should wear the splint as directed.

  • You may loosen the elastic around the splint if your child's toes become numb, tingle, or turn cold or blue.

  • Do not put pressure on any part of your child's cast or splint. It may break. Rest your child's cast only on a pillow the first 24 hours until it is fully hardened.

  • Your child's cast or splint can be protected during bathing with a plastic bag. Do not lower the cast or splint into water.

  • Only give your child over-the-counter or prescription medicines for pain, discomfort, or fever as directed by your caregiver.

  • It is very important to keep all follow up appointments. Not following up as directed may result in a worsening of your child's condition or a failure of the fracture to heal properly.


  • Your child has continued severe pain or more swelling than they did before the cast was put on.

  • The area below the fracture becomes painful.

  • Their skin or toenails below the injury turn blue or gray, or feel cold or numb.

  • There is drainage coming from under the cast.

  • Your child's cast gets damaged or breaks.