Hyperextension of the knee is a condition that occurs when the knee extends too far backward beyond the normal range of motion. It causes excess stress to the knee structures and back of the knee joint, often leading to pain, swelling, and tissue damage.
In extremely severe cases, a hyperextended knee can damage the ligaments, cartilage, blood vessels, nerves, and other stabilizing structures in the knee.
Although hyperextension of the knee can occur in anyone, it is a common sports injury among athletes. Because of weaker joint stability, female athletes have a higher risk of a hyperextended knee injury than male athletes.
Recovery time for a hyperextended knee injury varies depending on the severity. In mild to moderate cases, a person may take two to four weeks to recover. In severe cases that require surgery, it may take six months or more to recover completely from surgical repair.
What causes a hyperextended knee?
Hyperextension of the knee usually occurs due to a direct blow to the knee or by anything that forces the knee joint to bend too far backward. Common causes of a hyperextended knee include
- Car accident: During a car accident when the knee may be forcefully impacted.
- Falling: Falling when the foot is caught.
- Landing hard: Landing incorrectly after a jump or unbalanced landing.
- Jumping on the back: When someone jumps on a person’s back suddenly without warning, it can cause the person to be off-balance, resulting in a hyperextended knee.
- Skiing: If a skier crashes on a snowbank, their body will continue to move forward while the feet are fixed, leading to a hyperextended knee.
- Sports: A hyperextended knee may be caused during sports that involve
- Extreme contact at high speeds such as football, soccer, skiing, or lacrosse.
- Flexibility and landing such as gymnastics.
- Quick changes in direction and leaping such as basketball.
- Sudden deceleration: Stopping suddenly when running keeps the momentum of the body moving forward while the feet are fixed, causing the knee to bend backward.
- Tackle: Leg tackle or tackling the front of the knee that pushes the knee backward.
What are the symptoms of knee hyperextension?
Symptoms of a hyperextended knee may vary from mild to severe depending on how far backward the knee was pushed and the severity of damage to the ligaments and surrounding tissues.
Common symptoms of a hyperextended knee include:
- Feeling of weakness: Feeling a sensation of giving out or buckling of the knee.
- Instability of the knee: The affected knee is less stable or sturdy than the healthy one.
- Knee pain: Moderate to severe localized knee pain, mild to sharp pain in the back of the knee, or pinching pain in front of the knee joint.
- Limited mobility: Difficulty bending or straightening the injured knee due to damaged ligaments, swelling of the knee, and weakness in the joint and pain.
- Popping sound: A hyperextended knee that is accompanied by a popping sound or sensation indicates that one of the knee ligaments is torn.
- Swelling: Fluid accumulates within the knee joint called “water on the knee,” causing swelling that reduces knee mobility.
- Visible bruising: Mild or severe bruising may appear on the skin in response to the injured soft tissues, ligaments, and/or cartilage.
What is the treatment of a hyperextended knee?
Typical treatment of a hyperextended knee is based on the RICE principle, which includes:
- Rest: The activity that caused the hyperextended knee must be immediately stopped, and the knee should be rested. It’s necessary to seek medical assistance. High-intensity activities and contact sports must be completely avoided during rest. The doctor may give anti-inflammatory medications and pain medications to help reduce swelling and pain.
- Ice: A piece of ice placed inside a small towel or piece of cloth should be applied to the affected knee for up to 15 minutes several times a day to reduce swelling and get some relief from pain.
- Compression: Wrapping the knee with a compression wrap or elastic support bandage reduces swelling and pain.
- Elevation: Elevate the injured knee above the heart whenever possible. This can be done by lying down on a bed with the leg resting on a pillow or comfortable support.
Treatment of severe cases of a hyperextended knee
- Surgery: Although surgery is less common, in severe cases, a hyperextended knee can result in tendon tear, tissue damage, or misalignment of the knee that requires surgical repair. Common surgical procedures include:
- Arthroscopy: Arthroscopic surgery involves inserting a small endoscopic camera through a small incision to get a clear view of the affected area and repair knee damages.
- Reconstruction: Reconstructive surgery may be performed to repair tissue damage caused by a hyperextended knee.
Physical therapy would be essential for a person undergoing surgery to regain muscle strength and restore their range of motion.
Prevention of a hyperextended knee
Wearing knee braces during sports or high-intensity activity may help prevent a hyperextended knee. Supporting the hyperextended knee after injury and resting for the first 48 hours after injury is essential for healing, stability, and preventing further hyperextension.
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