Knee Dislocation

What is a knee dislocation?

A knee dislocation means that the bones in your knee have moved out of place so that the bones do not fit together correctly. A knee can get dislocated if you tear the ligaments in your knee. Ligaments are strong bands of tissue that connect one bone to another.

How does it occur?

Your knee can be dislocated by:

  • suddenly twisting your body while your feet stay in one place
  • hitting the knee very hard
  • hyperextending the leg; that is, forcibly straightening your leg and knee past a normal position.

What are the symptoms?

Symptoms of a dislocated knee include:

  • severe pain right after you hurt it
  • not being able to bend or straighten the knee properly
  • a misshapen knee
  • rapid swelling of the knee joint
  • tingling or numbness in the foot.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and how you hurt your knee. He or she will examine you. You will have X-rays to see if any bones are broken.

Your provider will also check your pulse at your ankle. You may have a test called an arteriogram to make sure blood vessels are not blocked. To do an arteriogram, your provider injects an X-ray dye into your arteries through a thin tube (catheter). With X-rays your provider watches the dye pass through your arteries on a screen. At the same time pictures are taken of the knee.

You may have an MRI to see what parts of your knee have been injured. An arteriogram may be done at the same time as an MRI. This combined exam is called an MRA (magnetic resonance arteriogram).

How is it treated?

A dislocated knee needs treatment right away to prevent permanent damage to the nerves and blood vessels.

Your healthcare provider will try to get the knee joint back into its correct position. This is easier to do if it is soon after the injury. If there has been a delay in getting medical care, your provider may give you an anesthetic before moving your knee back in place to help prevent pain and muscle spasms.

Your healthcare provider will usually put your knee in a splint for the first few weeks. Then, depending on your injury, your provider may recommend that you start early range-of-motion exercises, or he or she may decide to put the knee back in a splint for a few more weeks. You may need to do exercises for your quadriceps (thigh muscles above the knee) to keep from losing strength in your leg.

Often there is damage to the ligaments and cartilage of the knee when it is dislocated. You may need surgery to repair the ligaments.

In some cases emergency surgery is necessary. You may need surgery if:

  • You have no pulse at the ankle.
  • The artery at the back of the knee joint is injured.
  • The bones cannot be moved back into the correct position.
  • The skin is cut and the bone is exposed.

How long will the effects last?

The effects are different from person to person. Recovery depends on the extent of the injury, particularly on how many ligaments were torn and whether you have nerve or artery damage.

How can I take care of myself?

Follow your healthcare provider's treatment plan. Rest and do not put any stress on your leg unless your provider gives you different instructions.

How can I help prevent dislocating the knee again?

To prevent dislocating the knee again:

  • Wear a knee brace if recommended by your provider.
  • Avoid dangerous sports and activities.
  • Move and use your body carefully.

Developed by RelayHealth.
Adult Advisor 2012.1 published by RelayHealth.
Last modified: 2011-02-04
Last reviewed: 2011-06-12
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2012 RelayHealth and/or its affiliates. All rights reserved.