Hyperextended knees are common injuries for athletes. Mild hyperextensions won’t require surgery, and you can recover with rest, ice and other at-home treatments. Don’t play through pain or ignore symptoms. This can make a mild injury worse and lead to more severe injuries like torn ligaments.
A hyperextended knee is an injury that happens when your knee is bent backward beyond its usual limit.
Sports injuries and other traumas apply a lot of force to your knee’s connective tissue (the tendons, ligaments and cartilage that hold it in place and help it move). Any force that pushes your knee further back than its usual limit can cause a hyperextension injury. After your knee is hyperextended, it might feel unsteady or “buckle” when you try to put weight on it.
Knee hyperextensions range from mild cases that you can treat at home to more severe injuries that will need surgery to repair.
Your ACL (anterior cruciate ligament) and PCL (posterior cruciate ligament) connect your thigh bone (femur) to your shin bone (tibia). They both cross the middle of your knee. Your ACL is at the front of your knee and your PCL runs along the back, behind your knee.
You MCL (medial collateral ligament) and LCL (lateral collateral ligament) are on the sides of your knee. They stabilize your knee and help it move sideways.
It’s possible that an injury can damage one or multiple ligaments in your knee, including during a hyperextension. Severe hyperextensions are common causes of ACL and MCL tears.
However, not all hyperextensions lead to ligament tears, and it’s possible to strain or tear ligaments without hyperextending your knee.
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Anyone can experience a hyperextended knee, but they’re most common in people who play sports.
Hyperextended knees are very common injuries, especially for athletes.
In addition to symptoms like pain and swelling, it might be hard to use your knee like you usually can after it’s hyperextended. This is especially true if you damaged other parts of your knee like tendons, ligaments or your meniscus when you were injured. Your knee might buckle (feel weak or unstable), and you might not be able to put weight on it like you’re used to.
Don’t “play through the pain” or try to “walk it off” if you hyperextend your knee. Ignoring symptoms can cause a mild injury to become worse, and can lead to more damage inside your knee.
See your healthcare provider if you’re in pain or have trouble moving your knee.
Symptoms of a hyperextended knee include:
If you hear or feel a pop inside your knee during your injury, it’s more likely you’ve torn one of your ligaments. Torn ligaments can also be extremely painful and make it hard or impossible for you to use your knee.
Most hyperextensions are caused during sports or other physical activities. Traumas like falling can also cause your knee to hyperextend. Anything that forces your knee backward can cause a hyperextended knee. Picture a football player getting tackled by their legs, or a basketball player landing awkwardly after a jump.
Your healthcare provider will diagnose a hyperextended knee with a physical exam and imaging tests. They’ll look at your knee, talk to you about your symptoms and see how limited your ability to use your knee is.
You’ll probably need at least one type of imaging test, including:
These will help your provider see the damage inside and around your knee. They’ll also show if you have a more serious injury like a torn ligament.
How your hyperextended knee is treated depends on the severity of your injury. If you only have mild symptoms and didn’t damage anything inside your knee, you should be able to treat your hyperextended knee at home by the following RICE:
Over-the-counter NSAIDs like aspirin or ibuprofen can reduce pain and inflammation. Talk to your provider before taking NSAIDs for longer than 10 days. Your provider might suggest exercises to increase the strength and flexibility in the muscles around your knee to help prevent future injuries.
It’s rare to need surgery after a hyperextended knee. However, if the injury that caused your hyperextension damaged tendons like your ACL or PCL, you might need surgery to repair those tears.
Most of the time, surgery to repair damage in your knees is an outpatient procedure, which means you can go home the same day. Your surgeon will perform what’s called a knee arthroscopy, a minimally invasive technique to repair the ligaments inside your knee.
How long it takes you to feel better depends on how severely your knee was hyperextended and any other injuries you experienced. If your hyperextension didn’t damage anything inside your knee and you don’t need surgery, it should take between a few weeks and a month to recover.
If you need surgery to repair more severe injuries it could take a few months before you can resume all your usual activities.
Talk to your healthcare provider or surgeon about a specific timeline for your recovery.
During sports or other physical activities:
Follow these general safety tips to reduce your risk of an injury:
You should expect to make a full recovery after hyperextending your knee. It’s a temporary injury that shouldn’t have long-term impacts on your health or your ability to play the sports you love.
If you experience a severe injury that requires surgery, you should expect to avoid the sport or activity that caused your hyperextension for at least a few months.
If you can do your job or schoolwork seated or without putting additional stress on your injured knee you shouldn’t need to miss work or school while you heal.
Talk to your surgeon or healthcare provider before resuming any physical activities while you’re recovering.
The outlook for people with hyperextended knees is very positive. Most injuries don’t require surgery, and you should be able to resume all your usual activities within a few weeks.
Talk to your provider if you’re experiencing symptoms like pain or swelling that get worse after a few days or if you can’t move your knee like you usually can.
Go to the emergency room if you notice any of the following:
A note from Cleveland Clinic
How much time will I miss? Is this a serious injury? Am I done for the season?
These are all questions that run through your mind when you hyperextend your knee. Fortunately, most hyperextended knees don’t require surgery, and you’ll be able to recover at home with over-the-counter treatments and by giving your body time to rest and heal.
If you do experience a more severe injury — like a ligament tear — you should still make a full recovery and get back to the sports and activities you love.
Last reviewed by a Cleveland Clinic medical professional on 02/16/2022.
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