Knee Sprain

What is a knee sprain?

A knee sprain is a joint injury that causes a stretch or tear in one or more of the knee ligaments. A sprain can be mild, moderate, or severe.

Ligaments are strong bands of tissue that connect one bone to another. The knee joint is held together by the cruciate and collateral ligaments. These ligaments connect the thighbone (femur) in the upper leg to the bones in the lower leg. The anterior and posterior cruciate ligaments cross each other inside the knee joint and keep the thighbone from sliding or rotating over the tibia (one of the 2 main bones in the lower leg). The medial and lateral collateral ligaments are on either side of the knee and keep the knee from moving side to side.

How does it occur?

A knee sprain most often happens while playing sports, but can happen during a fall or an accident where the leg is twisted. Collateral ligaments are usually injured when hit by a force on the side opposite the ligament. The cruciate ligaments can be injured by sudden twisting movements or from being hit directly.

What are the symptoms?

There is usually pain and a popping sound at the time of the injury. The knee may start to swell right away or the swelling may be gradual.

How is it diagnosed?

Your provider will examine the knee by moving it in different ways. You may need to have an MRI or an X-ray.

How is it treated?

To treat this condition:

• Put an ice pack, gel pack, or package of frozen vegetables, wrapped in a cloth on the area every 3 to 4 hours, for up to 20 minutes at a time.
• Raise the knee on a pillow when you sit or lie down.
• Take an anti-inflammatory medicine such as ibuprofen, or other medicine as directed by your provider. Nonsteroidal anti-inflammatory medicines (NSAIDs) may cause stomach bleeding and other problems. These risks increase with age. Read the label and take as directed. Unless recommended by your healthcare provider, do not take for more than 10 days.
• Follow your provider’s instructions for doing exercises to help you recover.
• Wrap an elastic bandage around your knee to keep the swelling from getting worse.
• Use a knee immobilizer to protect the knee as directed by your provider.
• Use crutches.

Usually surgery is not needed unless you have a complete ligament tear or several ligaments are hurt at the same time.

How long will it take to get better?

If you return to sports or other activities before you have fully recovered, you may worsen your injury and have permanent damage. Everyone recovers from injury at a different rate. Follow your healthcare provider's instructions and advice. In general, the longer you have symptoms before you start treatment, the longer it will take to get better.

How can I prevent a knee sprain?

You may be able to avoid knee sprains by having strong thigh and hamstring muscles and stretching the leg muscles. In activities such as skiing, make sure your ski bindings are set correctly by a trained professional so that your skis will release when you fall.