Hyperextension of your knee is when it is extended or straightened too far, resulting in a knee injury, like a ligament sprain. Depending on the severity of your injury, symptoms may include pain, stiffness and swelling. Rest, ice, compression and elevation of your knee will help reduce your symptoms, but physical therapy and surgery may be necessary for a full recovery. Consult your physician for a diagnosis and treatment options.
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Causes and Injuries
A blow to the front of your knee or a forceful kick to your leg in sports, such as soccer, may cause your knee to hyperextend. Other causes include a sudden stop, landing from a jump with a locked knee and chronic knee hyperextension due to joint laxity. Injuries include meniscus tears, bone bruises, fractures and ligament sprains, especially of the posterior cruciate ligament or PCL. If these injuries go untreated, secondary injuries may develop, like tendonitis, stress fractures and arthritis.
With an acute hyperextension of your knee, you may experience sudden pain, swelling and muscle weakness, according to a 2010 article in the “Journal of Orthopaedic Surgery and Research." You may also be tender below your kneecap, and have bruising and joint instability. With hypermobility and chronic knee hyperextension, knee soreness and swelling may develop overtime and the severity of your symptoms may vary compared to acute hyperextension injuries. Additional symptoms include sensations of “giving way” or “catching” of your knee, atrophy or muscle loss and impaired gait because of knee stiffness and pain.
To manage pain and reduce inflammation, rest, ice, wear a compression wrap and elevate your leg. Take over-the-counter pain medications like acetaminophen to further alleviate pain. Wear a knee brace to immobilize your knee and use crutches to avoid putting weight on your injured knee while walking. Once pain and swelling subside, your physician may recommend physical therapy or surgery, depending on the type of injury you sustained and the severity of it. Physical therapy consists of range-of-motion, strength and stability exercises to regain knee function. With a PCL sprain, you may continue to experience some joint laxity and occasional swelling and pain following physical therapy, according to a 2007 “Hospital of Special Surgery Journal” article. This may decrease your athletic performance and lead to further deterioration of your knee.
If symptoms persist after conservative treatment, your physician may recommend surgery. A complete rupture of your PCL, or multiple knee injuries such as a PCL and meniscus or cartilage tear, may also require surgery because of the severity of the damage and debilitating symptoms. During surgery, torn ligaments and cartilage are repaired and loose pieces of tissue in the joint capsule are removed. On the other hand, surgery increases your risk of infection, may cause additional scar tissue to develop and usually requires a longer recovery time.