Dislocated Knee

What is a dislocated knee?

A dislocated knee has bones that are displaced. When they are displaced they do not fit together correctly. This can happen when ligaments in the knee are torn. Ligaments are strong bands of tissue that connect one bone to another.

How does it occur?

Your knee can be dislocated by:

• twisting the body while your feet stay in one place
• hitting the knee (front, back, or side) 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 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 and possibly order a test called an arteriogram to make sure blood vessels are not blocked. To do an arteriogram, your provider injects a solution into your arteries through a tube (catheter). This solution can be seen on X-rays. Your provider watches the fluid 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 structures have been injured in your knee. An arteriogram may also 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 healthcare provider may choose to begin early range-of-motion exercises or may choose to put the knee back in a splint for a few more weeks. You may have to do exercises for your quadriceps (thigh muscles above the knee) to prevent losing strength in your leg.

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.

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

How long will the effects last?

The effects vary from person to person. Recovery depends on the extent of the injury, particularly on how many ligaments were torn and whether there has been nerve or artery damage.

How can I take care of myself?

Follow your healthcare provider's treatment plan. Rest and do not put more stress on your leg unless your provider tells you to do otherwise.

How can I help prevent dislocating the knee again?

To prevent dislocating the knee again:

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