Sprains or tears of the knee ligaments are common athletic injuries. Knee ligaments hold together your femur to the bones of the tibia and fibula under the knee. The medial collateral ligament (MCL) and the lateral collateral ligament (LCL) are located at the sides of your knee. Athletes involved in contact sports, such as football or basketball, are more likely to injure their ligaments.
The knee depends mostly on these ligaments and surrounding muscles for stability and so is easily injured. Any direct contact with the knee or quick change of direction can injure a ligament. The injury of these ligaments are considered "sprains" and are graded on a severity scale.
Grade 1. The ligament has been slightly injured. It is slightly stretched, but is still able to keep the knee joint stable.
Grade 2. Such a partial rupture means that the ligament is a bit loose.
Grade 3. This injury is more often referred to as a complete rupture of the ligament. The ligament is separated into two pieces and the knee joint is unstable.
Symptoms
Pain on the side of the knee.
Swelling over the part of the injury.
Instability - the feeling that the knee "gives way"
The treatment is usually conservative with splints and physiotherapy, but if there is a complete rupture, then surgical repair of the ligament is usually chosen.