What Is Knee Dislocation?

Written by WebMD Editorial Contributors

• What Is Knee Dislocation?
• Knee Dislocation Symptoms
• Knee Dislocation Causes
• Knee Dislocation Diagnosis
• Knee Dislocation Treatment
• Knee Dislocation Recovery
• Knee Dislocation Complications
• More

A dislocated knee is when the three bones of your knee are out of place and aren’t aligned the way they should be. It can happen if the structures in your knee are abnormal. Some people are born with a knee dislocation (congenital dislocation of the knee). Most of the time, knee dislocations happen when a traumatic event thrusts the bones in your knee joint out of place with great force. It’s an emergency, and it’s very painful.

If your knee is dislocated, your thigh and shin bones may be completely or partially out of place. A dislocated knee is different from a dislocated kneecap. That’s when your kneecap (patella) slips out of place. Doctors sometimes call this a patellar subluxation.

Dislocated knees are rare, but serious. Other parts of your knee might also have been damaged at the same time. You need to see a doctor right away.

When you dislocate your knee, you may hear a popping sound. Common symptoms include:

• It hurts a lot. Your knee is in so much pain that you can’t move or straighten it.
• Your knee feels unstable.
• It’s swollen and severely bruised.
• Parts of the knee look like they’ve been knocked out of place.
• You aren’t able to do activities or sports you normally do.

If it’s not something you were born with (congenital dislocation), knee dislocation happens as the result of serious trauma such as:

• 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 overextend your knee (bend it backward 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.

You should go to to the emergency room at once so they can examine your knee from many angles to confirm the injury.

Examination. Your doctor will look at your knee, and they’ll want to hear how you injured it. They’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.

They’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.

Ankle-brachial index test. To look for changes in blood flow, they may do this test. It compares your blood pressure measured at your ankle to your blood pressure measured at the usual place on your arm. If your ankle-brachial index number is low, it may mean the dislocation has caused a problem with the blood flow to your legs.

Electromyography. Your doctor may use this procedure to check your muscles and nerves. They’ll insert a needle into your muscle to record electrical activity. Electrodes on the surface can measure the speed and strength of signals from your nerves.

Imaging. 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. An MRI or ultrasound also can show whether there’s nerve injury.

Your doctor may order an arteriogram, an X-ray outlining blood flow in your arteries and veins. It’s another way to see if the knee dislocation damaged blood vessels.

Your treatment will depend on how badly you’ve been injured.

No-surgery option. If the damage to your knee isn’t too severe, your doctor may try to pop your bone back into place by pressing and moving your leg in certain ways. This will be very painful, probably. Your doctor will offer to give you medicine so that you won’t feel what’s happening. After your bone is back in the joint, you’ll likely need to wear a splint for a few weeks to allow your knee to heal without moving or bearing any weight.

Surgery. Your doctor may need to do surgery to correct the dislocation and other damage from your injury, including:

• Broken bones
• Torn ligaments
• Damaged nerves
• Damaged blood vessels

You might not have surgery until 1 to 3 weeks after you’re hurt, to allow time for the swelling to go down. While you wait, you’ll need to wear a splint, keep your leg raised, and put ice on the injury.

Your surgeon may do arthroscopic knee surgery. This is done through small cuts made around your knee.

You might need “open” surgery, with bigger cuts. The type you need depends on the damage to the rest of your knee.

After surgery, you may wear different knee braces as you heal. Some let you bend your knee — to ease stiffness.

After you’re finished wearing splints or braces, your doctor should send you to a physical therapist to rehab your knee. You’ll do exercises to strengthen the leg muscles around your knee and work to bring a full range of motion back to your joint.

Your recovery will depend on how serious your injury is and whether you had damage to your blood vessels and nerves. If you got treatment quickly, you will likely heal well. Recovery from a knee dislocation can take a long time. You may need to rehab your knee for up to a year. You’ll recover faster if you stick to your doctor’s advice. Athletes who dislocate their knees may be able to return to their sports, but they might not be able to perform at the same level as before.

Knee dislocation is a serious injury that can have major complications if it isn’t treated right away. If the dislocation causes a big loss of blood flow to your legs, your doctor may have to amputate. Knee dislocations also can lead to blood clots in deep veins of your legs (deep venous thrombosis).

Acute compartment syndrome is another common complication. This happens when the swelling in the muscles causes pressure to build up in the blood vessel, nerves, and muscles. If this happens, it’s painful. You’ll need to see a doctor right away.

Top Picks

Dislocated kneecap – NHS

A dislocated kneecap is where your kneecap (patella) moves out of place. It is usually caused by an injury to the knee. Get medical advice as soon as possible if you think you have a dislocated kneecap.

Urgent advice: Get help from NHS 111 if:

You’ve injured your knee and:

• it’s very painful
• it’s swollen or bruised
• you cannot stand up or move your knee
• you think your kneecap dislocated and then moved back into place

You can call 111 or get help from 111 online.

Immediate action required: Go to A&E if:

You’ve injured your knee and:

• your knee has changed shape
• it becomes very swollen very quickly
• you felt a pop or snap in your knee
• you can see bone sticking out of your skin
• it’s bleeding heavily

Call 999 if you’re unable to get to A&E.

While you are waiting for medical help

If you think you have dislocated your kneecap, there are some things you can do while waiting for treatment:

Don’t

• do not raise the affected knee

• do not try to stand or walk on the affected leg

• do not try to put the kneecap back into place yourself

Treatment for a dislocated kneecap

A dislocated kneecap often moves back into place by itself.

Even if it does, you will still need to get it checked by a doctor. You will usually need X-rays or an MRI scan.

If your kneecap does not go back into place by itself, a doctor may have to move it back. You will be given a local anaesthetic and may be offered a sedative so you do not feel any pain.

Surgery may be needed if you have badly damaged your knee. Some people may also need surgery to stop the knee from dislocating again.

After treatment, you’ll need to go to follow-up appointments to check your knee is healing properly.

Recovering from a dislocated kneecap

It can take 6 to 8 weeks to fully recover from a dislocated kneecap, but you will usually be able to walk using the affected knee within a few days.

You may be given a knee support to wear for 2 weeks to help it heal. If walking is painful, using a crutch may help.

Your doctor or a physiotherapist will show you knee exercises that you should do regularly to help speed up your recovery.

Things you can do to help your recovery

There are some things you can do to help with the recovery of a dislocated kneecap.

Do

• take painkillers like paracetamol or ibuprofen to help with pain

• keep your knee and lower leg slightly raised and supported when resting to reduce swelling

• do knee exercises throughout the day to stop your knee getting stiff

• stay as active as you can

Page last reviewed: 25 January 2023
Next review due: 25 January 2026

Treatment Habitual dislocation of the patella – Orthopedics Ruslana Sergienko

The patella, or patella, is a small oval bone located above the condyle of the femur in front and above the knee.

Dislocation of the patella (patella) is a common injury in teenagers. Treatment is possible with the help of rehabilitation or surgery.

Causes of patellar luxation

One of the most common causes of pain in the patellofemoral joint is impaired movement of the patella in the intercondylar groove. The quadriceps heads and ligaments help center the patella in the intercondylar groove of the femur during movement. For various reasons, an imbalance in the traction of the muscles is possible, as a result of which one of the heads pulls the patella more than the other. This, in turn, causes a large pressure of the patella on the articular cartilage of the intercondylar sulcus on one side compared to the other. Constant asymmetric pressure leads to damage to the articular cartilage. In this case, the cartilage in the outer part experiences more pressure during movements. If such an effect occurs for a long time, softening begins first, and then the destruction of the cartilage. This phenomenon is called chondromalacia patella.

Finally, dislocation of the patella can occur if one of the walls of the intercondylar sulcus (usually the outer one) is less developed than the inner one, or the depth of the intercondylar sulcus is not sufficient to keep the patella from dislocation. In these cases, the patella also tends to dislocate from the joint. With repeated dislocations, rapid degeneration of the cartilage of the femur and patella occurs and causes persistent pain in the patient. It is worth noting that dislocations and subluxations tend to recur as the surrounding patella-supporting ligaments are stretched or damaged and the femoral condyles wear away. Complications of dislocation of the patella can be considered subchondral fractures.

Conservative treatment

After patellar luxation, the main goal of treatment is to restore the ability of the knee joint to function normally and restore its strength in order to avoid repeated displacements of the patella.

In case of traumatic dislocation, it is necessary to free the knee joint from blood and provide it with rest. It is recommended to apply cold. After a few days, rehabilitation begins, the goal of which is to restore the normal functioning of the knee and the breadth of the range of motion. At the initial stage, it is recommended to use a fixing knee brace. The main goal of rehabilitation is to strengthen the hip extensor muscles, as the extensor force of the knee passes through the patella.

In some patients, the recovery process occurs due to proper rehabilitation, i.e. through conservative treatment. Other patients may have problems, of which the most unpleasant is recurrent patellar dislocations. The frequency of dislocation of the patella is different: from 1-2 times a year to several times a day. This can provoke the development of patellofemoral arthrosis in the knee joint and, in addition, drastically reduces the quality of life. Recurrent dislocations should be treated surgically.

Surgical treatment

During the operation, the task becomes to restore the ligament located on the inside of the patella and femur, which was torn due to dislocation. This relatively simple operation is very effective: a result that can be considered good or very good is achieved in more than 90% of cases.

TRUST YOUR HEALTH CARE TO REAL PROFESSIONALS!

Treatment. Knee-joint. Patella Dislocation Company Blog

Description of the disease, symptoms and causes, methods of treatment.

Description of the disease:

The patella is the largest sesamoid bone of the human skeleton, located in the thickness of the quadriceps femoris muscle. The bone is perfectly accessible for examination and palpation. The main function of the patella is to protect the knee joint from lateral displacements and from mechanical shocks from the front.

Dislocation of the patella is not a life-threatening condition, but it will not be possible to correct it on your own. The first symptoms appear immediately: the patient is worried about a sharp pain, especially when moving. Often the knee joint is bent in a forced position.
Half an hour later, inflammatory edema increases, which will not subside for quite a long time after the reduction of the dislocation. Given the rather difficult situation of the patient, it is recommended to seek urgent help from a traumatologist to provide qualified assistance. If everything is done rationally and quickly, the treatment of patellar dislocation will take a little time and quickly return the patient to his feet.
If a severe mechanical injury has been inflicted, the knee joint is edematous and there are suspicions of dislocation of the patella, then it is easy to verify the correctness of the diagnosis on your own: the patella will be visually displaced, especially when comparing a healthy and damaged limb. Do not forget that even with its conditional correct location, the patella can be damaged; it’s about a break.

Symptoms and causes:

General symptoms:

Most often, dislocation of the patella occurs when playing sports. Also, a dislocation can occur when the leg suddenly turns in the knee joint, the foot of which is firmly on the ground, or when it falls on the knee.

Why should you seek help from a qualified specialist?

Lack of timely treatment can lead to disability and delay the further rehabilitation process.

Methods of treatment:

Conservative treatment:

• consists in the reduction of the dislocation (first, the leg is bent at the hip joint, to loosen the tension of the tendons of the 4th head of the thigh muscle, then the injured limb is unbent at the knee joint and the dislocation is eliminated, at the end, a plaster splint is applied or an orthosis with a changing angle of flexion is put on).;
• after the reduction of the dislocation, a control radiograph is prescribed to confirm the reduction of the dislocation;
• after that, the patient walks in a longuet for 4-6 weeks, during which physiotherapy (interferential therapy, ultrasound with hydrocortisone) and medical procedures (massage) aimed at eliminating inflammation in the knee joint and preventing the onset of contracture, and myostimulation can be performed to maintain the 4 head of the thigh muscle in good shape and prepare for the active stage of rehabilitation.