Injuries to one or more of the ligaments in the knee results in pain and a significant loss of stability. Ligament injuries are most associated with athletes who participate in high demand sports like soccer, football and basketball. Ligament injuries can be caused by twisting your knee with the foot planted, getting hit in the knee, hyper-extending the knee, jumping and landing on a flexed knee, stopping suddenly when running, or suddenly shifting weight from one leg to the other. Complete tears to the ligaments often require surgery to correct, especially if the athlete hopes to return to high demand sports. However, partial tears and sprains do not usually require surgery and can be successfully treated with conservative treatment methods.

There are four primary ligaments in your knee. They act like strong ropes to hold the bones together and keep your knee stable.

• Cruciate Ligaments are the two major ligaments located inside the knee joint, which control the back and forth motion of the knee. They cross each other to form an “X.” The anterior cruciate ligament (ACL) is in the front and posterior cruciate ligament (PCL) is in the back.
• Collateral Ligaments are located on the sides of the knee and control the side to side motion and brace it against unusual movement. The medial collateral ligament (MCL) is on the inside and the lateral collateral ligament (LCL) is on the outside.

  Knee sprains occur when the ligaments are injured and are graded on a severity scale.

• Grade 1 Sprains. The ligament is mildly damaged in a Grade 1 Sprain. It has been slightly stretched, but is still able to help keep the knee joint stable.
• Grade 2 Sprains. A Grade 2 Sprain stretches the ligament to the point where it becomes loose. This is often referred to as a partial tear of the ligament.
• Grade 3 Sprains. This type of sprain is most commonly referred to as a complete tear of the ligament. The ligament has been split into two pieces, and the knee joint is unstable.