The stretching or tearing of the ligaments (strong bands of tissue that connect bones together) that support the knee.
Intense pressure to the knee area, such as being in a car accident or suffering a sports injury, is the most common cause of a knee sprain. In these situations, an individual will usually exert too much force on his or her knee, such as twisting it in the wrong direction, stopping suddenly or landing on the knee in an awkward position.
A knee sprain can cause such symptoms as pain, swelling, tenderness and limited range of motion of the knee. Knee sprains are graded according to their severity:
- Grade 1 – Stretching and microtearing of ligament tissue
- Grade 2 – Partial tearing of ligament tissue
- Grade 3 – Severe or complete tearing of ligament tissue
Many knee sprains can heal on their own, without the help of surgery. If this is the case, patients are typically advised to rest, elevate the affected leg, use a knee brace and undergo physical therapy treatment to strengthen the muscles around the injured ligament.