A patella fracture is a break in your kneecap, the bone that covers your knee joint. It’s usually caused by a traumatic injury, such as a fall or a blow to your kneecap. A patella fracture can be simple or complex. Some fractures require surgery to repair. Recovery can be long, and side effects are common.
A patella fracture is a break in your kneecap — the small, flat bone that covers and protects your knee joint like a shield. It’s usually caused by direct injury like a fall on your knee, a blow to your knee or a collision, lik with the dashboard in a car accident. A patella fracture is a serious injury, which can impact your ability to bend or straighten your knee. Some patella fractures are simple, but this small bone is also capable of breaking into many pieces.
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A patella fracture is usually caused by a direct impact to your knee. Depending on the force applied, it may create a hairline crack, break into two pieces or it may break into many small pieces. Patella fractures can cause the extensor mechanism of your knee to no longer function properly. The quadriceps and patellar tendon attach to your patella, which normally allows you to flex and extend your knee. The patella is covered with cartilage, which provides a cushion for your knee joint. The cartilage can be injured with this type of fracture, which can lead to post-traumatic arthritis.
Patella fractures are not common. They represent only 1% of all fractures. They are twice as likely to occur in men as in women.
A patella fracture is usually caused by a direct blow to your kneecap, such as in a fall, from a sports injury or from a car accident. More rarely, it can also be caused by a sudden muscle contraction in your knee.
A patella fracture will often leave you unable to walk. If you think you can, but it is still painful, it’s probably best not to try until you have been diagnosed. Once you have been diagnosed and treated for a patella fracture, you’ll be allowed to bear weight in a knee immobilizer, hinged knee brace or cast locked in full extension. Your orthopaedic surgeon will let you know how much you can bend your knee. At first, you won’t be allowed to flex your knee, but flexion will be allowed slowly, over time. You’ll be allowed to bear as much weight as you feel comfortable.
Your healthcare provider will ask about your symptoms and what happened at the time of the injury. Then they’ll examine your knee. They might have you try to extend your leg. If you can’t, that will likely necessitate surgical intervention. They may also be able to feel the edges of the fractured bone pieces through your skin.
They will check for open wounds and for signs of hemarthrosis — blood from the broken bone pieces collecting in your joint, which can cause excessive swelling. They will take X-rays or even a CT scan to define the fracture.
The healing process for a patella fracture can vary, depending on the severity of your break and whether you had surgery or not. Most people will be feeling good in about six weeks, and able to return to all of their normal activities within three to six months. Some people report long-term symptoms of pain or stiffness, and some choose to continue wearing a knee brace for support.
While most fractures are done healing within three to six months, it’s not uncommon for people to report long-term complications. These can include:
A note from Cleveland Clinic
Patella fractures are not common, but traumatic injuries do happen. If you’ve fractured your patella, you may have a long recovery ahead. Pain is usually moderate and manageable with over-the-counter medications. Meanwhile, it’s very important to be patient and committed to the healing process. Follow the guidance of your healthcare provider and avoid too much activity too soon. When the time is right, be diligent with your physical therapy exercises. Your healthcare provider will guide you through the process to ensure that you restore as much mobility as possible to your knee.
Last reviewed by a Cleveland Clinic medical professional on 11/12/2021.
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