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Kneecap Subluxation

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KEY POINTS

  • The kneecap normally glides over a groove in the thigh bone that makes up the knee joint. A kneecap subluxation means that your child’s kneecap moves partly out of this groove for a short time.
  • Your child needs to change or stop doing the activities that cause pain until the injury heals.
  • Treatment may include using a splint or brace and having physical therapy.

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What is kneecap subluxation?

The kneecap normally glides over a groove in the thigh bone that makes up the knee joint. A kneecap subluxation means that your child’s kneecap moves partly out of this groove for a short time.

What is the cause?

Kneecap subluxation usually happens when your child’s leg and knee move past a normal position. Your child’s kneecap is more likely to move out of place if he or she has any of the following:

  • Thigh muscles that are over- or under-developed
  • An abnormal knee structure
  • Knock-kneed (knees turn in)
  • Born with weak or loose ligaments, which are are strong bands of tissue that connect one bone to another

What are the symptoms?

Symptoms may include:

  • Swelling
  • Pain when your child bends or straightens his or her leg
  • Weakness in the knee
  • Clicking, popping or grinding under the kneecap

How is it diagnosed?

The healthcare provider will ask about your child’s symptoms and medical history and examine your child. Tests may include:

  • X-rays
  • MRI, which uses a strong magnetic field and radio waves to show detailed pictures of the bone

How is it treated?

Your child will need to change or stop doing the activities that cause pain until the injury has healed.

The healthcare provider may recommend stretching and strengthening exercises and other types of physical therapy to help your child heal.

The provider may recommend that your child use a splint or brace to keep his or her kneecap in place.

How can I take care of my child?

Follow the full course of treatment prescribed by your healthcare provider. In addition:

  • Keep your child’s knee up on pillows so that it is above the level of the heart when he or she sits or lies down.
  • Put an ice pack, gel pack, or package of frozen vegetables wrapped in a cloth on the injured area every 3 to 4 hours for up to 20 minutes at a time.
  • Give your child nonprescription pain medicine, such as acetaminophen, ibuprofen, or naproxen. Read the label carefully and give your child the correct dose as directed.
    • Nonsteroidal anti-inflammatory medicines (NSAIDs), such as ibuprofen, naproxen, and aspirin, may cause stomach bleeding and other problems.
    • Check with your healthcare provider before you give any medicine that contains aspirin or salicylates to a child or teen. This includes medicines like baby aspirin, some cold medicines, and Pepto-Bismol. Children and teens who take aspirin are at risk for a serious illness called Reye’s syndrome.
    • Acetaminophen may cause liver damage or other problems. Do not give more doses than directed. To make sure you don’t give your child too much, check other medicines your child takes to see if they also contain acetaminophen. Unless recommended by your healthcare provider, your child should not take this medicine for more than 5 days.
    • Make sure that your child does the exercises recommended by your healthcare provider.

Ask your healthcare provider:

  • How long it will take to recover
  • What activities your child should avoid and when he or she can return to normal activities
  • How to take care of your child at home
  • What symptoms or problems you should watch for and what to do if your child has them

Make sure you know when your child should come back for a checkup. Keep all appointments for provider visits or tests.

How can I help prevent kneecap subluxation?

It may help if your child does exercises that keep the thigh muscles strong, especially the muscles on the inner side of the thigh. Ask your child’s healthcare provider or physical therapist about these exercises. Your child may need to wear a knee brace.

Developed by Change Healthcare.
Pediatric Advisor 2022.2 published by Change Healthcare.
Last modified: 2019-06-11
Last reviewed: 2019-06-09
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2022 Change Healthcare LLC and/or one of its subsidiaries
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