Knee may feel unstable and may be unable to walk on the injured knee. You have persistent, significant difficulty walking or putting weight on your leg. If you think that you have sustained this type of injury you should immediately seek advice from a physiotherapist. Sudden instability in the knee. Pain behind your knee – and sides of your knee is an obvious sign of a hyperextended knee. There is a painful “popping” or clicking sound. Hyperextension can range from a mild injury, which is sore but heals in two to four weeks, to a severe injury requiring surgery and extensive knee pain medicines. It is not an overuse type of injury that develops gradually over time. You might hear a “pop” at the time of injuring your knee. Most joints in the body produce popping sounds, and the knee isn’t an exception. A hyperextended knee can damage ligaments, cartilage and other stabilizing structures in the knee. The most common type is called iliotibial (IT) band tendonitis.It occurs when the iliotibial band becomes swollen and irritated, and then catches of the end of the thigh bone as the knee bends back and forth. Similarly, when you go through a full arc motion, your knee might crack (hyperextended knee). There is knee pain without an injury; it hurts during or after activity. The knee does not have full motion. Knee swelling within the first few hours of the injury. How to Pop Your Knee Safely. When you squat or stand, you will hear some noises from your knee. This may also be associated with the knee feeling unstable or giving way. There are times when swelling of tendons that surround the knee can cause the tendons to catch on the knee as the knee bends. Hyperextended knee injuries generally happen suddenly due to force. This may happen after a jump or change in direction or after a direct blow to the side of the knee. Symptoms of a Hyperextended Knee . If the knee feels “loose” when you resume activity, a visit to the doctor may be in order. And it is painless. When a hyperextended knee injury happens, it is normally accompanied by a loud “pop” sound as the knee is forced backward beyond its normal range. Your doctor may take x-rays, recommend an MRI, or suggest a visit to a physical therapist. Young children have softer bones because they're still growing, so a hyperextended knee can result in a chip of bone being pulled away from the main bone when the ligaments stretch too far. Essentially, the knee bends back on itself. The knee is a strong and complex joint, but it has a very limited range of motion. Knee injuries are common across all sports. Possible Causes of a Knee Pop. (The knee feels wobbly, buckles, or gives out.) Pain on the outside and back of the knee. Tendon Snapping . If your knee is hyperextended, however, the leg will appear to curve back, with the knee behind an imaginary straight line drawn from ankle to hip. Symptoms of pop in the knee. Swelling may occur within a couple of hours after hyperextending your knee. Knee instability is often caused by weak surrounding muscles. Since hyperextended knees are basically a problem of too-loose ligaments and tendons around the knee, you can cause or exacerbate such looseness through poor alignment in yoga poses. Do you feel like popping up your knee? Hyperextended knee injuries where a ‘pop’ is heard at the time of the injury and swell quickly often involve the anterior cruciate ligament (ACL). Some associate a knee pop with solely one condition, when actually this can point to a number of knee conditions. Feeling or hearing a "pop" in the knee at the time of injury. The knee is “locking,” or getting stuck, and is not able to move. The knee is swelling–with or without a traumatic (sudden) injury. A hyperextended knee injury occurs when the knee extends past a normal range of motion in the straight position. As a hinge joint, it can only flex in one direction, and that leaves its structures very vulnerable to being forced out of place if they are hit or twisted. Working on balance and isolation exercises can significantly strengthen the knee and prevent injury. You felt a pop; Your knee is locked and will not straighten ; You have a significant weakness when trying to straighten the knee. Most knee injuries are mild, and the athlete can expect to return to play relatively soon. The knee does not have good strength.