What is kneecap dislocation?
The kneecap (patella) is normally positioned over the front of the knee joint at the base of the thighbone (femur). A kneecap can be dislocated, or moved out of its normal position, when:
- The inner edge of the kneecap is hit, pushing it toward the outer side of the leg. This can happen more easily if there is patellar tracking disorder (the kneecap is already slightly out of place).
- The foot is firmly planted pointing outward, and the knee is bent with the thigh turned inward. This kind of injury is common during many sports activities.
What are the symptoms of kneecap dislocation?
Symptoms may include severe pain, swelling, or a popping sensation, followed by a feeling that something is out of place. You may not be able to bend your knee, or it may look misshapen. You may have cool, pale skin or numbness and tingling in or below the affected knee.
How is kneecap dislocation diagnosed?
The doctor will ask about your symptoms and past health and do a physical exam. You may have imaging tests, such as an X-ray, ultrasound, or MRI.
How is kneecap dislocation treated?
Your doctor may recommend pain medicine, home care, and physical therapy to help you heal. The doctor may suggest using a brace (immobilizer) or elastic bandage to support your knee while it heals. In some cases, surgery may be needed.
How can you care for yourself when you have a dislocated kneecap?
- Rest your knee by not putting weight on your leg until your doctor says it is okay.
- Put ice or a cold pack on your knee for 10 to 20 minutes at a time. Try to do this every 1 to 2 hours for the next 3 days (when you are awake) or until the swelling goes down. Put a thin cloth between the ice pack and your skin. Do not get the brace or elastic bandage wet.
- Prop up your leg on a pillow when you ice it or anytime you sit or lie down for the next 3 days. Try to keep it above the level of your heart. This will help reduce swelling.
- Be safe with medicines. Read and follow all instructions on the label.
- If the doctor gave you a prescription medicine for pain, take it as prescribed.
- If you are not taking a prescription pain medicine, ask your doctor if you can take an over-the-counter medicine.
- Follow your doctor's instructions for using crutches, a brace (immobilizer), or an elastic bandage to support your knee while it heals.
- If you use an elastic bandage, make sure it is snug but not so tight that your leg is numb, tingles, or swells below the bandage. Loosen the bandage if it is too tight.
- Go to physical therapy if your doctor suggests it. Follow your therapist's instruction for home exercises.
Kneecap dislocation: When to call
Call 911 anytime you think you may need emergency care. For example, call if:
- You have sudden chest pain and shortness of breath, or you cough up blood.
Call your doctor now or seek immediate medical care if:
- You have signs that your kneecap may be dislocated again, including:
- Severe pain.
- A misshapen knee that looks like a bone is out of position.
- Not being able to bend or straighten the knee.
- Not being able to walk or bear weight on the knee.
- Your foot is cool or pale or changes color.
- You cannot feel or move your toes or ankle.
- You have signs of a blood clot, such as:
- Pain in your calf, back of the knee, thigh, or groin.
- Redness and swelling in your leg.
Watch closely for changes in your health, and be sure to contact your doctor if:
- Your pain and swelling get worse.
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