What is kneecap subluxation?

Your kneecap normally glides over a groove in the bones that make up your knee joint. A kneecap subluxation means that your kneecap moves partly out of this groove for a short time.

What is the cause?

Kneecap subluxation usually happens when you force your leg and knee to straighten past a normal position. Your kneecap is more likely to move out of place if:

• Your thigh muscles are over- or under-developed.
• You have an abnormal knee structure.
• You are knock-kneed (knees turn in).
• You were born with weak or loose ligaments. Ligaments are strong bands of tissue that connect one bone to another.

What are the symptoms?

Symptoms may include:

• Swelling
• Pain when you bend or straighten your leg
• Weakness in your knee

How is it diagnosed?

Your healthcare provider will ask about your symptoms and medical history and examine you. You will have X-rays.

How is it treated?

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

Your healthcare provider may recommend stretching and strengthening exercises and other types of physical therapy to help you heal.

Your provider may recommend that you use a splint or brace to keep your kneecap in place.

How can I take care of myself?

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

• Keep your knee up on pillows when you sit or lie 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.
• Take nonprescription pain medicine, such as acetaminophen, ibuprofen, or naproxen. Read the label and take as directed. Unless recommended by your healthcare provider, you should not take these medicines for more than 10 days.
  • Nonsteroidal anti-inflammatory medicines (NSAIDs), such as ibuprofen, naproxen, and aspirin, may cause stomach bleeding and other problems. These risks increase with age.
  • Acetaminophen may cause liver damage or other problems. Unless recommended by your provider, don’t take more than 3000 milligrams (mg) in 24 hours. To make sure you don’t take too much, check other medicines you take to see if they also contain acetaminophen. Ask your provider if you need to avoid drinking alcohol while taking this medicine.
• Do the exercises recommended by your healthcare provider.

Ask your provider:

• How and when you will hear your test results
• How long it will take to recover
• If there are activities you should avoid and when you can return to your normal activities
• How to take care of yourself at home
• What symptoms or problems you should watch for and what to do if you have them

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

How can I help prevent a subluxing kneecap?

It may help to do exercises that keep your thigh muscles strong, especially the muscles on the inner side of your thigh. Ask your healthcare provider or physical therapist about these exercises.