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Patellar Fracture

Medically reviewed by Last updated on Aug 31, 2022.

What is a patellar fracture?

A patellar fracture is a break in your kneecap. Treatment depends on how the kneecap breaks. Broken pieces may move out of line or break through the skin.

Knee Anatomy

What are the signs and symptoms of a patellar fracture?

  • Pain when your knee is touched or when you move your leg
  • Swelling and bruising around your knee
  • Being able to straighten your leg but not to bend it
  • Not being able to stand up or put weight on your leg

How is a patellar fracture diagnosed?

Your healthcare provider will ask about the injury and examine you. He or she will look for bone that broke through the skin. He or she may be able to tell if the bone pieces are in their correct places by touching your knee. You may need any of the following tests:

  • An x-ray may show the kind of fracture you have. Healthcare providers may also x-ray your other leg to compare kneecaps.
  • A CT scan or an MRI may show a fracture or other injury. You may be given contrast liquid to help healthcare providers see your kneecap better. Tell the healthcare provider if you have ever had an allergic reaction to contrast liquid. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell the healthcare provider if you have any metal in or on your body.
  • A bone scan is a test to look at your fracture and check for infection. You will get a radioactive liquid, called a tracer, through a vein in your arm. The tracer collects in your bones and pictures are taken.

How is a patellar fracture treated?

  • A brace, cast, or splint may be needed. These supportive devices stop the kneecap from moving and help it heal. You may also need to use crutches to help you move around while your kneecap heals.
  • Medicines can help prevent or fight pain or a bacterial infection. You may also need a Td vaccine. This vaccine is a booster shot to help prevent tetanus. You may need the Td vaccine if bone broke through the skin.
  • Closed reduction may be used to move the broken pieces back to their correct places without surgery. External fixation may be used to hold your kneecap in place, and then removed.
  • Surgery may be used to move the broken pieces back into their correct positions. Wires, pins, screws, or bands may be used to hold the pieces in place. Surgery may also be used to remove part or all of your kneecap.
  • Physical therapy may be recommended. A physical therapist teaches you exercises to help improve movement and strength, and to decrease pain.

What can I do to help my patellar fracture heal?

  • Rest your knee as directed. Crutches help rest and support your knee when you walk. Your healthcare provider will tell you when you can start to use crutches. Follow instructions about how much weight to put on your leg.
    Walking with Crutches
  • Apply ice to help decrease swelling and pain. Use an ice pack, or put crushed ice in a plastic bag. Cover it with a towel before you place it on your knee or supportive device. Apply ice for 15 to 20 minutes every hour for 2 days, or as directed.
    Ice and Elevation
  • Elevate your knee above the level of your heart as often as you can. This will help decrease swelling and pain. Prop your leg on pillows or blankets to keep it elevated comfortably. Do not put pillows directly under your knee.
    Elevate Leg

Call your local emergency number (911 in the US) or have someone call if:

  • You suddenly feel lightheaded and short of breath.
  • You have chest pain when you take a deep breath or cough.
  • You cough up blood.

When should I seek immediate care?

  • Your cast or splint breaks or gets damaged.
  • Your foot or toes are swollen, cold, numb, or they turn white or blue.
  • Your leg feels warm, tender, and painful. It may look swollen and red.

When should I call my doctor or bone specialist?

  • You have a fever.
  • Your pain gets worse, even after treatment.
  • You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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