What is the Anatomy of the ACL?
The anterior cruciate ligament (ACL) is one of the main ligaments of the knee joint and is responsible for preventing the tibia (shinbone) from sliding out in front of the femur (thighbone). An anterior cruciate ligament injury is quite common in the athletic population, especially athletes involved in sports that require sudden changes in directions and stops. Approximately 200,000 ACL injuries are reported each year in the United States. Injuries can range from a simple sprain to a complete ACL tear requiring surgical intervention from Dr. Matthew Provencher, Vail, Aspen, Colorado Springs and Denver, Colorado area orthopedic knee specialist.
The ACL runs through the knee joint from the front of the shinbone to the back of the femur. This ligament plays an important role in anatomy of the knee. It helps maintain stability and provides protection to the knee’s menisci. An anterior cruciate ligament injury typically occurs in active individuals from a direct blow to the joint or from unnatural twisting and pivoting. When the ACL is stretched past its normal range of motion, the shinbone slides out from under the thighbone, causing an ACL tear or stretch. Roughly 50 percent of ACL injuries occur in combination with an additional injury, such as damage to the meniscus, articular cartilage, or other ligaments.
What are Anterior Cruciate Ligament Injury Symptoms?
Patients often experience knee pain, swelling and limited range of motion following an anterior cruciate ligament injury. A slight sprain or stretch of the ligament may cause mild to moderate pain along with a slightly unstable sensation when the knee moves. An ACL tear may cause moderate to severe knee pain and swelling, as well as a “popping” sensation when the injury occurred.
How to Know if you Have an ACL Tear
If a patient believes they have experienced an injury to the ACL, Dr. Provencher will begin the diagnosis with a thorough physical examination of the affected joint. He will perform a variety of tests in many cases to help confirm the anterior cruciate ligament injury, such as the Pivot Shift, Anterior Drawer and Lachman tests. A series of x-rays and an MRI scan are usually performed to evaluate the soft tissues and bony structures of the knee joint in great detail. These diagnostic tests will also help Dr. Provencher determine if additional injuries to the joint are present.