TRANSCRIPT Lt Col Jerman Knee injuries are not unusual among people who are extremely active, especially those involved in sports. Captain Laydon, can you tell us about some common knee injuries? Capt Laydon Sure thing, Dr. Jerman. Knee injuries are often the result of a one-time traumatic event, and can range in severity from minor strains to complete tears. Structures within the knee that are most commonly injured include ligaments, tendons, and cartilage. A fairly common example of a knee injury is damage to the anterior cruciate ligament, or ACL. Traumatic injuries to the ACL usually result from a sudden twisting motion combined with the knee moving inward. This can occur during athletic activities that involve pivoting. Non-traumatic, or non-contact, ACL injuries are more common in female athletes than male athletes. These injuries are often caused by poor biomechanics of landing after a jump. Increased bending at the hip and knee during landing can significantly decrease the likelihood of ACL injuries related to jumping. Other knee ligaments that can suffer injury are the posterior cruciate ligament, called the PCL, and the medial collateral and lateral collateral ligaments. The PCL can be injured by a direct blow to the knee. The medial collateral and lateral collateral ligaments, or MCL and LCL, stabilize the knee, limiting side-to-side motion. The MCL is often injured due to a blow to the outside of the knee, while the LCL is frequently injured by trauma to the inside of the knee. Another common knee injury involves the meniscus. The meniscus is a C-shaped piece of cartilage that acts like a pad between the femur, or thighbone, and tibia, or shinbone. The meniscus can be injured if the knee is twisted while bearing weight, and a partial or total tear can occur. An MCL injury may also result in a tear in the medial meniscus. If the tear is small, the meniscus may heal without surgery. However, if the tear is large, a fragment of the meniscus may prevent normal movement of the knee, and surgery may be required.