Patellar Fracture

What is a patella?

The patella is also called the kneecap. It is a thick, triangle-shaped bone that protects the front of the knee joint. The patella helps the muscles of the thigh bend and straighten the leg.

What are the types of patellar fractures?

A patellar fracture is a break in your kneecap. If you have a nondisplaced fracture, the broken pieces of your patella have stayed in the right place. A displaced patellar fracture means that the broken pieces have moved out of place. When there is a break in the skin covering the kneecap, it is called an open fracture. When there is no break in the skin covering the kneecap it is called a closed fracture. Your patellar fracture may also be called one of the following types:

• Transverse: A transverse fracture is a single, horizontal (side-to-side) break in the kneecap.
  
  
• Stellate: A stellate fracture is a break in the kneecap in the shape of a starfish.
  
  
• Comminuted: A comminuted fracture occurs when the kneecap breaks into many pieces.
  
  
• Vertical: A vertical fracture is a single, vertical (top-to-bottom) break in the kneecap.

What causes a patellar fracture?

Direct or indirect trauma can cause a patellar fracture. A car accident or a sports injury are examples of direct trauma. A direct blow to your knee or a hard fall on your knee are also examples of direct trauma. A strong contraction (tightening) of the thigh muscles when the knee is bent is an example of indirect trauma. This contraction pulls the tendon connected to the kneecap which breaks the kneecap. If you had total knee arthroplasty surgery, you are more likely to get or have a patellar fracture. This is called a periprosthetic patellar fracture. Having osteoporosis (a disease where bones become thin and brittle) or arthritis (a disease where there is joint swelling) increases this risk.

What are the signs and symptoms of a patellar fracture?

If you have a periprosthetic patellar fracture, your knee may feel weak and unstable. This can make you feel afraid of falling when walking up or down stairs. With this type of fracture, it may be painful to use the stairs, or you may have no signs or symptoms. With other types of patellar fractures, you may have one or more of the following:

• Pain when your knee is touched or when you move your leg.
  
  
• Swelling and bruising around your knee.
  
  
• Being able to straighten your leg at the knee, but not being able to bend your leg at the knee.
  
  
• You may not be able to put all of your weight (stand up) on your injured leg.

How is a patellar fracture diagnosed?

Your caregiver will ask you about the injury and examine you. He may learn if the bone pieces are in their correct places by feeling your knee. You may need one or more of the following tests:

• X-rays: You may need x-rays of the injured leg to check for bone fractures and other problems. More than one picture may be taken. Caregivers may also x-ray your other leg.
  
  
• MRI: This test is also called magnetic resonance imaging. During the MRI, pictures are taken of your knee. Caregivers use these pictures to look for a patellar fracture.
  
  
• Computerized tomography scan: This test is also called a CT scan. A special x-ray machine uses a computer to take pictures of your knee. You may be given dye before the pictures are taken, to help caregivers see the pictures better. People who are allergic to iodine or shellfish (lobster, crab, or shrimp) may be allergic to some types of dye. Tell your caregiver if you are allergic to iodine or shellfish.
  
  
• Bone scan: A bone scan may be done to check for a patellar fracture. For this test, you are given a small amount of radioactive dye through an intravenous line. This is a small tube that is placed into one of your veins. Pictures are taken of your bones. The dye helps a fractured patella bone show up better in the pictures.

How is a patellar fracture treated?

You may have any of the following:

• Immobilization: If you have a nondisplaced patellar fracture, you will usually need to have it immobilized for a few weeks. A cast, splint, or hinged brace may be put on your leg to stop the kneecap from moving. These supportive devices often extend from the groin to the ankle. A cast, splint, or hinged brace may make you more comfortable, and will prevent more injury. These devices support your knee and may help it heal. Ask your caregiver for more information about casts, splints, and hinged braces. You may need to use crutches. Caregivers will tell you if you can put weight on your leg (use your leg to walk).
  
  
• Pain medicines: You may be given medicine to decrease the pain caused by a patellar fracture.
  
  
• Antibiotics: This medicine is given to help treat or prevent an infection caused by bacteria.
  
  
• Tetanus shot: If you have an open patellar fracture, you may need a tetanus shot. This medicine helps prevent a disease called tetanus.
  
  
• Surgery: Ask your caregiver for more information about the type of surgery that you need:
  
  
  • Irrigation and debridement: If you have an open patellar fracture, irrigation and debridement may be done. This procedure is done to clean and remove objects, dirt, or dead tissue from the fracture area. Ask your caregiver for more information about irrigation and debridement. After this procedure, you may need immobilization, or open reduction and internal fixation of your patella.
    
    
  • Open reduction and internal fixation: A displaced patellar fracture is often treated with open reduction and internal fixation (ORIF) surgery. During ORIF, caregivers make a large incision (cut) over your patella. The broken pieces of bone and ligaments are moved back to their correct places. Bone pieces and ligaments may be secured using wires, pins, screws, or bands. Your leg is placed in a cast or other device to hold the patella in place as it heals.
    
    
  • Closed reduction: With a closed and displaced patellar fracture, you may need to have a closed reduction. During this surgery, caregivers move the broken pieces of bone and ligaments back to their correct places without large incisions. External fixation may be used to hold your patella in place, and then later removed. You may have a cast, splint, or brace on your leg to help your knee heal.
    
    
  • Patellectomy: A patellectomy may be done to treat a severely comminuted patellar fracture. This type of surgery may be done when ORIF cannot be done to repair your patellar fracture. During a partial or complete patellectomy, part or all of your kneecap is removed. Immobilization is used after surgery to allow your leg to heal.
  
  
• Physical therapy: A physical therapist may teach you exercises to help strengthen your leg muscles. This caregiver may also help you learn how to use and care for your splint, brace, or crutches. Caregivers will help you become active soon after your injury or surgery. Being active will help prevent problems such as blood clots. Caregivers will tell you if, and how much weight you can bear on your leg while your knee is healing.

What can I do to help my patellar fracture heal?

• Elevate your leg: While sitting or lying down, prop your leg up on pillows to keep it above the level of your heart. This helps decrease swelling and pain, and improves blood flow. It can also help your knee heal faster.
  
  
• Use ice: Ask caregivers if you should use ice on your knee. Ice causes blood vessels to constrict (get small), which helps decrease swelling, pain, and redness. Ice may be used right after the injury or surgery, and for the next 24 to 48 hours. Make an ice pack by wrapping a bag of crushed ice in a towel. You may need to put the ice pack on your knee for 15 to 20 minutes every hour. Do not sleep with the ice pack in place, because you can get frostbite.

What are the risks of having a patellar fracture?

• If you need a cast or splint, your knee may get stiff. After using immobilization or having surgery, your knee may still be painful. It may not look like it did before the injury or surgery. Even after treatment, your patella may not heal as it should. You may get an infection after surgery. If you have ORIF surgery, the broken pieces of bone or the hardware may move out of place. You are at higher risk of osteoarthrosis (cartilage loss) in your knee after patella surgery. You may get a blood clot in your leg. This can cause pain and swelling, and it can stop blood from flowing where it needs to go in your body. A blood clot can break loose and travel to your lungs. A blood clot in your lungs can cause chest pain and trouble breathing. This problem can be life-threatening.
  
  
• If your patellar fracture happened after having total knee arthroplasty surgery, you may need to have knee surgery again. Without treatment, your kneecap may not heal. You may have pain or weakness, or you may get an infection. You may not be able to move your leg as well as you did before your injury.

Where can I find more information?

• American Academy of Orthopaedic Surgeons
  6300 North River Road
  Rosemont , IL 60018-4262
  Phone: 1- 847 - 823-7186
  Web Address: http://www.aaos.org/
  

When should I call my caregiver?

Call your caregiver if:

• Your knee pain is getting worse, even after taking medicine to decrease pain.
  
  
• After having surgery, there is fluid or pus coming from your wound.
  
  
• Your knee is swollen and feels warm, and the area around your wound is painful and red.
  
  
• You have a fever.
  
  
• You develop new symptoms, or your symptoms are worse than before.
  
  
• You have chest pain or trouble breathing that is getting worse over time.
  
  
• You have questions or concerns about your patellar fracture, medicine, or care.

When should I seek immediate help?

Seek care immediately or call 911 if:

• Your foot or the toes of your injured leg are swollen, feel cold, or get numb (lose feeling), or they turn white or blue.
  
  
• You suddenly feel lightheaded and have trouble breathing.
  
  
• You have new and sudden chest pain. You may have more pain when you take deep breaths or cough. You may cough up blood.
  
  
• Your leg feels warm, tender, and painful. It may look swollen and red.

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 caregivers to decide what care you want to receive. You always have the right to refuse treatment.

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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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