What to Do About a Dislocated Knee

The knee is the joint in the middle of your leg that connects the femur (thigh bone) to the tibia (lower leg bone), You also have a third bone, the patella (kneecap). The joint also contains different types of cartilage to help it move smoothly, as well as muscles, ligaments, and nerves. All together, that adds up to the biggest joint in your body.

The knees function to support your weight and let your legs bend so you can move. The knees help with activities like walking, running, and jumping.

A dislocation of the knee is when one or more of the bones moves out of position. Dislocations are quite painful and make it extremely difficult or impossible to use the joint. A dislocation can also damage the soft tissues that support the joint.

The providers at Rapid Response Urgent Care in Granada Hills, California, see their share of dislocated knees, and they caution patients never to try to move the bone back into position by themselves. If you’ve dislocated your knee, here’s what you can expect and what you should do.

Types of knee dislocations

Doctors classify dislocations based on how much the bones in the joint move:

Complete dislocation (luxation): the bones in your joint are totally separated and pushed out of place
Partial dislocation (subluxation): the bones still touch, just not as completely as usual

Dislocations can also be described by which bone or bones are involved.

A patella dislocation occurs when your patella is forced outside of the trochlear groove, a vertical groove between the bottom of your femur and the top of your tibia that allows the kneecap to slide back and forth for movement. As a result, the joint can no longer move. Most commonly, the patella pops out to the side of the groove.

While you should seek professional help, sometimes a dislocated patella can correct itself.

And we should note that a patella dislocation differs from a knee dislocation, which is much more serious and involves your femur and tibia.

A knee dislocation occurs due to serious trauma such as:

Car accidents

If your knee collides with a hard surface like the dashboard, the force may be strong enough to dislocate your knee.

Sports injuries

If you collide with another player, with the ground while your knee is bent, or if you bend it backward (overextend) more than it should go, a dislocation may result.

Hard falls

If you fall on a bent or overextended knee, such as while running or by accidentally stepping in a hole, you can dislocate the knee joint.

When you dislocate the knee, you may hear a popping sound as the bones move. Additional symptoms include:

Pain (so much that you can’t move or straighten the joint)
Instability
Swelling
Severe bruising
Nonnormal appearance

You need to come into Rapid Response Urgent Care to determine the extent of the damage and what needs to be done to fix the knee.

Examining and treating a knee dislocation

To diagnose the problem, your provider may palpate different areas of your leg to see if the problem is just with the bone(s) or if you’ve also damaged any ligaments. Ligament damage is common with knee dislocations.

They’ll also check what your skin looks and feels like below your knee, because dislocating the knee joint may damage nerves or blood vessels, restricting blood flow and changing the skin’s color and temperature. Such damage could also affect blood flow or your sense of touch below the knee. They may also perform a number of tests like an MRI or an ankle-brachial index test to determine blood flow.

Treatment depends on the injury’s severity. If there’s not much damage, your provider may try to pop the bone back into its normal location through a series of precise moves. It’s extremely painful, so they’ll give you pain medication to help.

After the bone is back in the joint, you’ll require a splint for a few weeks so your knee won’t move or bear any weight and can heal.

If you have a lot of damage, you may need surgery to repair broken bones, torn ligaments, damaged nerves, and damaged blood vessels.