What is knee hyperextension?

In older children and adults, hyperextension of the knee can lead to a tear of a ligament in the knee, specifically the anterior cruciate ligament.Knee hyperextension is an injury that occurs when this joint has to extend backward beyond its normal range of motion. When this happens, a lot of stress is placed on the structures of the knee and the back of the knee.

This injury can be suffered by anyone, since it is usually caused by falling badly after a jump. However, it is usually more common in people who play sports. The injury can damage ligaments, cartilage, and other structures that contribute to joint stability.

In addition, it should be mentioned that, in young children, this condition can lead to a detachment of a small piece of the main bone if the ligaments are stretched too much. This is because people in the younger ages have softer bones, since they are in a growth period.

In older children and adults, hyperextension of the knee can cause a tear in a ligament in the knee, specifically the anterior cruciate ligament.

Causes of knee hyperextension

Knee hyperextension is usually the result of a direct blow to the knee or the forces generated during dry braking. In short, among the most common causes that usually produce this injury are:

  • Pushing the femur or kneecap onto the tibia and placing excess stress on one or more of the major ligaments within the joint.
  • An unexpected impact to the front of the knee, which will cause a backward movement of the joint. It usually happens in traumatic physical situations.

What are the symptoms that this injury produces?

When this injury occurs, the knee, as we already know, bends excessively causing swelling, pain, and tissue damage. In the most severe cases, the ligaments, both the anterior and posterior cruciate, can be injured. Furthermore, the cruciate ligaments are also often torn in this type of injury.

Depending on the degree of injury, the symptoms will varyThese will also depend on the person and the strength of each person’s knee. However, patients, regardless of the degree of injury, usually develop a series of common symptoms such as:

  • Reduced stability of the knee: when the injury is minor, it is very possible that the knee loses stability and that the patient has a feeling that the joint is going to fail.
  • Pain: Like almost all physical injuries, knee hyperextension causes localized pain. This pain will affect one area or another depending on the ligament it affects.
  • Loss of mobility: after this injury, the mobility of the joint can also be altered. The cause of this may come from the triggered swelling.
  • Edema and swelling: Once the injury has occurred, the inflammation can appear immediately or take a little longer, but it always appears. In addition, it is normal for edema and bruises to form around the joint, since it is the body’s way of responding when there are injured tissues.

Diagnosis of knee hyperextension

When diagnosing this injury, it is important to identify a number of characteristic symptoms. As we already know, it can cause serious damage to the major ligaments in the knee. The images can also help determine if a more serious soft tissue injury has occurred. However, among the signs that appear, if there has been a serious injury to the ligament, we find:

  • At the time of extending the knee it occurs as a click.
  • The injured leg is unable to bear weight.
  • The swelling that occurs.
  • The joint becomes swollen and warm and red from internal bleeding.


Knee hyperextension is an injury to this joint that occurs when the knee is extended backward beyond its limit. As a result, the ligaments can tear, leading to a long recovery period. If this injury occurs, go immediately to the doctor to treat the problem as soon as possible and promote treatment and recovery.

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