Symptoms

• Hyperextension can cause pain and swelling in the knee. In more severe cases, the injury can impair movement and stability, causing extreme pain and swelling, according to Mayo Clinic physical medicine and rehabilitation specialist Edward R. Laskowski, M.D.
  
  

Causes

• Knee hyperextension is often a sports-related injury, especially in jumping sports such as basketball and gymnastics. Landing improperly after a jump can hyperextend the knee, says Laskowski.
  
  

Treatment

• The injury may be treated with pain relievers or anti-inflammatory drugs, rehabilitation exercises, stabilizing braces, or rest. Surgery may be recommended in severe cases that involve ligament tearing.
  
  

Expert Insight

• During recovery, avoid activities that can aggravate your injury. Laskowski says the leg should be rested for two to four weeks to ensure proper healing.
  
  

Considerations

• If you need surgery, a full recovery could take six months or longer. For a child with a hyperextended knee, reports Laskowski, surgery may wait until she reaches her adult height.