Dislocated Knee

What is a dislocated knee?

In a dislocation of the knee, the bones in the knee are displaced. When they are displaced they do not fit together correctly. For this to occur, many ligaments must be torn. Ligament are strong bands of tissue that connect one bone to another.

How does it occur?

Your knee can be dislocated from:

• twisting the body while the feet are fixed
• hitting the knee (front, back, or side) very hard
• hyperextending the leg (hyperextension is increasing the angle of the knee joint past its normal range of motion).

What are the symptoms?

Symptoms of a dislocated knee include:

• severe pain immediately after injury
• inability to bend the knee properly
• deformity of the knee
• rapid swelling of knee joint
• tingling or numbness in the foot.

How is it diagnosed?

The doctor will review your cause of injury and symptoms and examine you. The doctor will order x-rays to see if any bones are broken.

The doctor 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, the doctor injects a solution into your arteries through a tube, or catheter. This solution is visible on x-rays. The doctor watches the passage of fluid through your arteries on a screen. At the same time pictures are taken of the knee. Your doctor may order an MRI of your knee.

How is it treated?

Dislocation of the knee requires urgent treatment to avoid permanent damage to the nerves and blood vessels.

The doctor will try to manipulate the knee joint back into its correct position. This is done more easily soon after injury. If there has been a delay in getting medical attention, the doctor may give you anesthesia before moving your knee back in place because of pain and muscle spasms.

In some cases emergency surgery is necessary. The doctor will perform surgery under these conditions:

• 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 correct position.
• The skin is cut and the bone is exposed.

The doctor will usually put your knee in a splint for the first few weeks. Then, depending on your injury, the doctor 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.

Often there is damage to the ligaments and cartilage of the knee after a dislocation. You may need surgery to repair or reconstruct 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 are torn and whether there has been nerve or artery damage.

How can I take care of myself?

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

What can I do to 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.