Patient education: Knee sprain (The Basics)

What causes a knee sprain? — A knee sprain happens the knee is bent or twisted too far in 1 direction.

Inside the knee are tough bands of tissue called ligaments. These hold the different bones together (figure 1). During a sprain, 1 or more of those ligaments stretch too far or even tear. This can cause pain and swelling and might make the knee feel unsteady.

What are the symptoms of a knee sprain? — The symptoms can include pain, tenderness, swelling, and bruising of the knee.

Some people with a knee sprain also find it hard to bend the knee or walk. Others might feel like their knee is unstable or "gives out" when they go up or down stairs. Also, some people cannot put weight on the leg with the injured knee.

Is there a test for a knee sprain? — A doctor or nurse might be able to tell if you have a sprain by doing an exam and learning about what happened to your knee. They might bend and straighten your leg to see what hurts and check how loose your knee feels.

In some cases, a doctor might order an X-ray to check for broken bones. But this is not always needed. Some doctors might use an ultrasound to look at the ligaments. Ultrasound is an imaging test that creates pictures of the inside of the body. Later, you might need to have other tests like an MRI.

How is a knee sprain treated? — Ask the doctor or nurse what you should do when you go home. Make sure that you understand exactly what you need to do to care for yourself. Ask questions if there is anything you do not understand.

You should also do the following. Think of the word "PRICE":

●Protect – To protect your knee, the doctor might order a knee brace or splint for you. An elastic bandage can also keep your knee from moving too much. Wear your knee brace or splint as your doctor tells you to.

●Rest – To rest your knee, use crutches and stay off of your feet. You might have to limit your activities and how much you walk or stand. This will help your knee rest while it heals.

●Ice – Apply a cold gel pack, bag of ice, or bag of frozen vegetables on your knee every 1 to 2 hours, for 15 minutes each time. Put a thin towel between the ice (or other cold object) and your skin. Use the ice (or other cold object) for at least 6 hours after your injury. Some people find it helpful to ice longer, even up to 2 days after their injury.

●Compression – "Compression" basically means pressure. You want to have your knee under slight pressure by having it wrapped in an elastic "compression" bandage. This helps reduce swelling and supports the knee. Your doctor or nurse will show you how to wrap your knee. Do not wrap it too tight or you might cut off the blood flow to your foot.

●Elevation – "Elevation" means keeping your knee raised up above the level of your heart. To do this, you can put your leg on some pillows or blankets while you are lying down, or on a table or chair while you are sitting.

You can also take medicines to relieve pain, such as acetaminophen (sample brand name: Tylenol), ibuprofen (sample brand names: Advil, Motrin), or naproxen (sample brand name: Aleve).

After a few days, when you have less swelling and pain, you can start to gently stretch your knee. You can also start to do gentle activities again.

Your doctor or nurse might also give you exercises to do as your knee heals. They might also recommend working with a physical therapist (exercise expert).

What follow-up care do I need? — Your doctor or nurse will tell you if you need to make a follow-up appointment. If so, make sure that you know when and where to go. If the injury is not healing as expected, your doctor might order an X-ray to check for a broken bone.

When should I call the doctor? — Call for advice if:

●Your pain or swelling is getting worse.

●Your foot or toes are blue or gray, and numb.

●You are unable to put weight on your knee, your knee "locks" in place, or your knee "gives out."

More on this topic

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Patient education: Meniscal tear (The Basics)
Patient education: Knee pain (The Basics)
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Patient education: Chondromalacia patella (The Basics)
Patient education: Iliotibial band syndrome (The Basics)
Patient education: Baker's (popliteal) cyst (The Basics)
Patient education: How to use crutches (The Basics)

Patient education: Anterior cruciate ligament injury (Beyond the Basics)
Patient education: Knee pain (Beyond the Basics)