One of the most common knee injuries is an anterior cruciate ligament sprain or tear, with an incidence in the United States approaching 200,000 annually. Nearly 150,000 ACL reconstruction surgeries are performed annually in the United States.
Athletes who participate in high demand cutting sports like soccer, football, and basketball are more likely to injure their anterior cruciate ligaments.
If you have injured your anterior cruciate ligament, you may require surgery to regain full function and stability of your knee. This will depend on several factors, such as the severity of your injury and your activity level. The TriHealth Orthopedic and Sports Institute comprises a comprehensive team of sports medicine orthopedic surgeons, non-surgical physicians, physical therapists, and athletic trainers to diagnose, treat, and prevent ACL injuries.
The classic ACL injury occurs during a non-contact event usually when decelerating, stopping suddenly, twisting, cutting, or jumping. Oftentimes the patient will hear or feel a “pop” at the time of injury and sometimes they may report brief a hyperextension of the knee joint. Immediately after the injury patients may be able to continue activity, however most of the time the patient is unable to continue regular activity and a few hours after injury the knee swells considerably. There is typically tenderness around the joint, loss of full range of motion, and discomfort applying weight to the leg.
When the ACL is injured as a result of direct contact, football is often the associated sport. Most often, the knee is subjected to a direct blow to the lateral side and other ligaments are injured in addition to the ACL. The most common multi-ligament injury is the ‘unhappy triad’ that includes the ACL, medial collateral ligament (MCL), and the medial meniscus.
Several studies have shown that female athletes have a higher incidence of ACL injury than male athletes in certain sports. It has been proposed that this is due to differences in neuromuscular control. Other suggested causes include differences in pelvis and lower extremity (leg) alignment, increased looseness in ligaments, and the effects of estrogen and relaxin on ligament properties.
Three bones meet to form your knee joint: your thighbone (femur), shinbone (tibia), and kneecap (patella). Your kneecap sits in front of the joint to provide protection and increase the mechanical efficiency of the extensor mechanism. Bones are connected to other bones by ligaments. There are four primary ligaments in your knee: the ACL, Posterior Cruciate Ligament (PCL), Medial Collateral Ligament (MCL), and Lateral Collateral Ligament (LCL). They act like strong ropes to hold the bones together and keep your knee stable.
- Collateral Ligaments: These are found on the sides of your knee. The medial collateral ligament is on the inside and the lateral collateral ligament is on the outside. They control the sideways motion of your knee.
- Cruciate Ligaments: These are found inside your knee joint. They cross each other to form an "X" with the anterior cruciate ligament in front and the posterior cruciate ligament in back. The cruciate ligaments control the back and forth motion of your knee. The anterior cruciate ligament runs diagonally in the middle of the knee. It prevents the tibia from sliding out in front of the femur, as well as provides rotational stability to the knee. The ACL sees stress with twisting and pivoting movements.