Cast Care: Arm or Leg Cast

About your child’s cast

A cast holds a part of the body in place. Casts are put on by an orthopaedic technologist, doctor, or nurse.

All casts start with light stockinette, followed by soft cotton, and finally plaster or fibreglass casting material.

The plaster cast

  • When applied, the plaster may feel warm at first. This is normal.
  • The cast will feel firm to touch in 10 to 15 minutes, but it will take up to 48 hours (2 days) to dry all the way through.
  • While drying, the cast may feel cold and clammy until it dries all the way through.

The fibreglass cast

  • Fibreglass is applied the same way as plaster.
  • Fibreglass dries in about 1 hour. It is lighter in weight and stronger than plaster.

There is a charge for fibreglass as well as some other devices. Your child's nurse, doctor, or other practitioner will discuss this with you.

Taking care of your child at home

The cast will change how your child uses the arm or leg. She will not be able to use it normally.

Please follow all the instructions you were given about how much physical activity your child should be doing with the cast on.

Signs of a problem with your child's cast

Look at your child’s cast 4 or 5 times per day. Call your doctor, nurse, or orthopaedic technician, or go to the hospital if your child has any of the following symptoms:

Fingers or toes that are blue, white, or very swollen


Get Adobe Flash player
If a cast is too tight, the skin may appear pale or bluish beyond the end of the cast when compared with the skin of a non-injured area.

Your child’s fingers or toes should be warm and pink. You can compare the temperature, colour, and size with your child’s other arm or leg.

Your child should not wear nail polish or rings while wearing a cast. You need to be able to see if the nails are blue.


Fingers and toes that cannot curl up or straighten out

With a leg cast, your child should be able to curl the toes downward, and pull them up and away from the cast. With an arm cast, your child should be able to straighten out all of the fingers and the thumb. Ask your child to move all of the toes or fingers many times throughout the day.

Sometimes if the fracture has just occurred, swelling may prevent your child's fingers or toes from opening fully.

Numbness (less feeling) in the arm or leg

Your child should be able to feel all of the arm or leg.

There should not be any feelings of numbness, tingling (pins and needles), or falling asleep in the injured arm or leg.

Smells and odours from the cast

It is normal for casts to start to smell if they have been in place for a long time. We worry about bad or foul smells, as they may indicate an infection under the cast.

A cast that feels tight to your child

If your child’s cast feels tight, it may mean that the arm or leg is swollen inside the cast. The swelling can make it difficult for blood to circulate through the arm or leg.

A cast that is soft or broken

If the cast is soft or broken, it may need to be repaired or replaced.

Taking care of your child’s cast at home

  • Keep your child’s cast clean and dry.
  • Clean a soiled cast with a damp cloth. Leave the area open to the air until it is dry. You can also use a hair dryer on a cool or cold setting.
  • Do not put anything under the cast to scratch, such as cotton, coins, or pens. It is normal for it to be itchy under the cast.
  • Do not cut or change the shape of your child’s cast.
  • Check the skin along the cast edges. Look for any blisters or redness.
  • Put the casted arm or leg up onto a pillow while your child is resting.

Removing the cast

Casts are taken off with an electric cast saw. This is not painful, but it is noisy. Your child will be given ear muffs to protect the ears during the procedure.

What to do if you have concerns

Take your child to see your family doctor or paediatrician if you are concerned about how the broken bone is healing or has healed.

Key points

  • Your child's cast may be made of plaster or fibreglass.
  • Look at your child's cast 4 or 5 times a day.
  • There may be a problem with your child's cast if your child's fingers or toes are blue, white, or swollen; if your child cannot bend or straighten the fingers or toes; if your child's arm or leg is numb or tingles; if there is a bad smell coming from the cast; if the cast feels tight to your child; or if the cast is soft or broken.

Preeti Grewal, RN, MN, APN

Jean Hohs, RTOrthopaed

Catharine Bradley, MSc, BSc (PT)

Benjamin A. Alman, MD, FRCSC


At SickKids:

Orthopaedic staff can be reached during the day at the following numbers:

  • Orthopaedic Clinic: 416-813-5840
  • Orthopaedic Technologist: 416-813-5785
  • Ward 5A (if your child was admitted): 416-813-6948