Simply put, if you are unable to straighten your knee after an injury, you may have a serious knee injury.
Knee injuries occur after a twisting injury or a direct contact injury. We shake off many knee injuries. After an injury, most of you will wonder if your damage is severe or perhaps just a simple strain. Some injuries cause only mild swelling. Some knee injuries might cause loss of motion. Determining if you have a severe knee injury is critical. After most mild knee injuries we are back on the road fairly quickly. What happens if you injure your knee and can’t straighten it? Is that a sign of a severe injury?
If you can’t straighten your knee you have a severe knee injury
After an injury, if you are not able to straighten your knee, there is a chance that you have sustained a serious knee injury. If an athlete is unable to straighten their knee after a severe knee injury, they should consider seeing an Orthopedic Surgeon.
After an injury, there are a few reasons why you might not be able to straighten your knee. Often you can’t straighten the knee simply because of pain and swelling. In cases where you can not straighten the knee because of swelling, you will notice that your ability to move the knee improves as the swelling goes down. Besides, when you have lost the ability to straighten your knee because of swelling, you do not usually feel as if something is stuck inside the knee and blocking your movement. In serious knee injuries, you will often feel as if something is blocking or locking your knee.
Here is a list of knee injuries which can make it difficult to straighten your knee.
Why Can’t I Straighten My Knee?
- Meniscus tear. Specifically a bucket handle tear of the meniscus. This is a unique tear where the torn piece of meniscus flips into the center of the knee joint. This torn piece then locks your knee and prevents it from straightening. If you have a bucket handle tear of the meniscus, you will find it impossible to straighten your knee completely. You will usually feel as if something is caught in the knee and preventing it from straightening. Most all bucket handle tears will require surgery to put the torn piece back into position. The torn portion should be repaired so that it has a chance of repairing itself. The success rate of getting a bucket handle tear to heal is very high.
- ACL tear. If you had a twisting injury and felt a pop, there is nearly a 75 % chance that your injured your ACL. Many athletes with an ACL tear will find it painful to straighten the knee. The knee isn’t locked, but it hurts too much to straighten it out. Within a few days of tearing your ACL, the swelling will start to diminish, and you will likely be able to straighten your knee. Sometimes athletes who tear their ACL will also rip the meniscus too. This is another reason why it might be hard to straighten the knee. If you twisted your knee and felt a pop, then noticed that you could not straighten your knee you should see a Sports Medicine Physician. Your next steps if you think you have an ACL tear are discussed here.
- Swelling. There are many reasons why your knee might be swollen. We explore the common causes of knee swelling here. Swelling is common after severe injuries due to bleeding. That can cause enough inflammation and pain that straightening the knee is just too painful. Bleeding can occur due to a meniscus tear, ACL tear or MCL tear.
- Patella or kneecap dislocations: Patella dislocations are far more common than previously thought. If you felt or heard a loud clunk or pop in the front of your knee while turning or you were struck in the front of your knee then it is possible that your kneecap came out of place and went back into place on its own. We call this a spontaneously reduced patella dislocation. Many people who dislocate their kneecap will develop significant swelling due to bleeding inside the joint. After a patella dislocation, you will find it difficult to straighten the knee due to pain. This post on patella dislocations goes into far more detail.
- Tendon Injuries: Some people can not straighten their knee due to weakness or tendon injury. Injuries to the quadriceps or patella tendon will affect your ability to straighten the knee. If one of those two strong tendons are torn, then you will not be able to straighten your knee. If you ripped your patella tendon or your quadriceps tendon, then you physically will not be able to straighten the knee. That is because the muscles which allow you to straighten the knee are no longer attached to your kneecap. That is why people who tear their patella tendon notice significant weakness. Patella tendon and quadriceps tendon injuries are more common in professional sports and adult weekend warriors. They are very rare in high school and collegiate sports. These are always a surgical problem. The patella or quadriceps tendon will need to be reattached and sutured to the patella.
If you have suffered an injury to your knee and you are unable to straighten it, then there is a good chance that you have sustained a severe knee injury. This is one of those times when it is wise to see an Orthopedic Surgeon sooner rather than later to determine what the diagnosis is and why you can’t straighten your knee.
Disclaimer: this information is for your education and should not be considered medical advice regarding diagnosis or treatment recommendations. Some links on this page may be affiliate links. Read the full disclaimer.