Hyperextended Knee Injury

What is a hyperextended knee injury and how is it treated?

A hyperextended knee injury happens when excessive pressure or force pushes your knee past its normal extension range of motion, while the knee is in a straightened position, and bends the knee backward. This usually happens while bearing weight on the limb. These injuries are not uncommon in athletes when landing from a jump to an extended knee position, or from an outside force to an extended knee, and are typically seen in basketball, volleyball, and gymnastics. Another possible hyperextension injury scenario is walking or running, and catching your foot in something like a pothole. This occurs because your foot and leg are placed and stable in the pothole, while the body's momentum is still moving forward. This momentum causes the hyperextension force. Hyperextension injuries can range from mild to severe depending on the amount of damage done to the stabilizing structures in the knee, i.e., knee cartilage, anterior cruciate ligament, menisci, and popliteus tendon.

Initial symptoms may include swelling, pain at the back and sides of the knee, pain with walking, and a feeling of instability with sport. You may also hear a "pop" with a hyperextension injury; this is usually with a forceful hyperextension and is indicative of a ligament tear, usually the ACL (anterior-cruciate ligament).

If you are experiencing these symptoms potential immediate treatment should utilize P.R.I.C.E.:

  • P: Protect, stop playing and use crutches or help from others, moving to a safe area so you can avoid bearing weight on the injured limb
  • R: Rest, avoid painful activity and abstain from sport at this time
  • I: Ice, ice targets pain receptors in the body and helps fight inflammation, ice for 10 to 15 minutes 3-4 times daily
  • C: Compress, an ACE bandage can be used to wrap the area to help decrease swelling and alleviate pain
  • E: Elevate, keep the leg raised above heart level in order to help decrease swelling in the area, try lying on your back with your foot rested on top of a couple of pillows

If you have feelings of instability with walking and or sport, limited range of motion, or pain, you should consult a physician to evaluate your knee. The physician may test for ligamentous laxity or tears within the knee, and possibly run diagnostic tests if need be. If it is determined that a ligament is torn, surgery may be warranted. If surgery is needed, it may take 6 to 9 months before return to sport, with physical therapy to assist the patient in meeting their goals. Even in more mild cases of hyperextension, the physician may still prescribe physical therapy to aide restoration of previous function. Physical therapy will typically consist of exercises for range of motion, strengthening, and balance training in order to regain stability to your knee.

The author of this article is Katie Riga, PT, DPT from Athletico - Michigan Ave.