What is knee dislocation?
A knee dislocation occurs when the bones that form the knee are out of place. A knee dislocation, more specifically, is when the bones of the leg (the tibia and fibula) are moved in relation to the bone in the thigh (femur).
The bones of the knee are held together by strong bands of tissue called ligaments. Each ligament is responsible for stabilizing the knee in a certain position.
For a knee dislocation to occur, these ligaments must tear. A partial dislocation is referred to as a subluxation. In some injuries, the kneecap (patella) and its ligaments are also disrupted.
How common is knee dislocation?
Knee dislocation is rare. Please discuss with your doctor for further information.
What are the symptoms of knee dislocation?
The common symptoms of knee dislocation are:
- A “Popping” Sensation
- Severe knee pain
- Being unable to straighten the knee
- Sudden swelling of the knee
- Being unable to walk
There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.
When should I see my doctor?
You should contact your doctor if you have any of the following:
- Extreme pain or swelling after a serious injury (such as a car crash)
- An obvious deformity of the knee
- Numbness in the foot
- No pulses in the foot
What causes knee dislocation?
Knee dislocation is usually the result of:
- Car accidents. If you bang your knee against a hard surface like your dashboard, the force of the blow may be strong enough to dislocate your knee.
- Sports injuries. This is less common than car accidents, but it’s possible to dislocate your knee if you collide with great force with another player or with the ground when your knee is bent, or if you over-extend your knee (bend it backwards farther than it’s supposed to go).
- Hard falls. It may happen to skiers or runners who lose control and fall on a bent or overextended knee. You may even dislocate your knee if you fall after stepping into a hole in the ground by mistake.
What increases my risk for knee dislocation?
Please discuss with your doctor for further information.
Diagnosis & treatment
The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.
How is knee dislocation diagnosed?
You should go to your doctor at once so she can see your knee from many angles to confirm the injury.
- Your doctor will look at your knee, and she’ll want to hear how you injured it. She’ll note whether or not your knee is misshapen and swollen and whether or not you can move it. Your doctor may push on different parts of your leg to see if you’ve also damaged any ligaments, which are bands of tissue that help to hold the knee in place. It’s common to tear ligaments when you dislocate your knee. She’ll also note what your skin looks and feels like below your knee, all the way to your foot. Dislocating your knee may cause damage to nerves or blood vessels, which may change the color and temperature of your skin. This could affect blood flow or your sense of touch below the knee. In extreme cases, you could lose your limb (amputation) if these severe complications aren’t addressed.
- Your doctor likely will want to see what’s going on inside your knee. An X-ray can confirm that your bone has been knocked out of the joint. It can also show if there are broken bones from your accident. An MRI can show whether any of the ligaments or other soft tissues in the knee have been damaged. It can also help a surgeon prepare to rebuild your knee.
How is knee dislocation treated?
- Relocation: The doctor will move your lower leg back into position, a process called reduction. Most doctors will do reduction after a person has been given pain medication or is given “conscious sedation,” where the patient is sedated enough to withstand the discomfort of relocation but not completely sedated. Relocation is an important early step in repairing damage to nerves, blood vessels, ligaments, and other tissues of the knee. Relocation is usually done by emergency and orthopedic doctors.
- If an arterial injury is determined to be present, immediate surgery by a trauma or vascular surgeon to repair the injured vessel(s) and maintain blood flow to the leg is necessary.
- Immobilization: To keep further injury from happening and to help with the beginning of healing, the entire knee joint will be kept in a splint or immobilizer. This will keep the knee from bending and help the tissues to start healing.
- Referral: A knee dislocation almost always has severe tears and sprains of the ligaments and sometimes has breaks in the bones of the knee. After swelling has gone down, the knee may need reconstruction surgery to regain function. A bone specialist (orthopedist) will need to see you after this injury.
Lifestyle changes & home remedies
What are some lifestyle changes or home remedies that can help me manage knee dislocation?
This injury should not be cared for at home. It is best to get medical care as soon as possible.
Placing ice on the injured area may help for some pain control and to decrease some of the swelling. But the most important treatment is to have a doctor assess the injury and relocate or put the knee back in place.
If you have any questions, please consult with your doctor to better understand the best solution for you.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: October 19, 2017 | Last Modified: December 6, 2019
Knee Dislocation. https://www.emedicinehealth.com/knee_dislocation/. Accessed October 19, 2017.
Dislocated kneecap. https://www.nhs.uk/conditions/dislocated-knee/Pages/Introduction.aspx. Accessed October 19, 2017.
What Is Knee Dislocation? https://www.webmd.com/pain-management/knee-pain/knee-dislocation. Accessed October 19, 2017.