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Knee

ACL Tear

Anterior cruciate ligament (ACL) tears are common in athletes of all ages. Annually more than 200,000 ACL injuries occur in the US. The majority of ACL tears are caused by noncontact injuries. 50% of ACL tears are accompanied by damage to other knee structures including the menisci or articular cartilage.

Knee anatomy

The knee is a complex joint that bears body weight and is vital to movement. It is composed of three bones – the thigh bone or femur, the shin bone or tibia, and the kneecap or patella. The patellar tendon connects the kneecap to the tibia. Other tendons connect muscles with bones. The muscles and tendons allow knee movement.

Four ligaments hold the bones together – 2 collateral ligaments and 2 cruciate ligaments. Both the cruciate and the collateral ligaments stabilize the knee. The collateral ligaments stabilize the knee when the leg is stretched. The cruciate ligaments provide stability when the knee is bent. Additionally, the menisci are tough pieces of cartilage in the knee that act as shock absorbers and distribute weight evenly to improve stability. There are two in each knee.

The ACL together with the posterior cruciate ligament (PCL) and meniscus are the main knee stabilizers. The cruciate ligaments connect the shin bone to the thigh bone. The collateral ligaments connect the thigh bone to the fibula (the smaller shin bone) and the tibia on both sides of the knee.

What causes an ACL tear?

ACL tears frequently occur in sports like soccer, basketball, football, tennis, skiing, and any sport that involves cutting and pivoting, requires a sudden change of direction, a rapid stop or sudden deceleration, jumping or landing abnormally, or a direct blow to the knee. However, even non-athletes can tear the ACL if there is enough force from twisting and hyperextension.

What are the symptoms of an ACL tear?

Most patients report hearing and feeling a sudden pop and giving way of the knee. Other symptoms include instability, pain, swelling, loss of range of motion, and difficulty walking or standing.

How is an ACL tear diagnosed?

Dr. Petrigliano is a knee expert and board-certified orthopaedic surgeon in Los Angeles. When the injury occurs in the field, he can examine the knee and make a tentative diagnosis. When he meets you in the ER, or his office, he will review your medical history, inquire about how you injured your knee, your pain and other symptoms; and conduct a physical exam including testing the injured knee’s range of motion, stability, and strength.

He will also evaluate the knee for associated injuries to other ligaments and the meniscus. Frequently an ACL tear occurs along with a medial collateral ligament tear or injury to the meniscus. Dr. Petrigliano will order x-rays to rule out fractures, and an MRI to reveal soft tissue damage. MRI imaging is the primary method to diagnose an ACL tear. Knee arthroscopy may be recommended to evaluate the tear and differentiate chronic and partial tears.

Treatment may be nonsurgical or surgical. The goal is to stabilize the knee and restore knee function to meet the patient’s needs and athletic demands.

Why choose Dr. Petrigliano?

Dr. Frank Petrigliano is an orthopaedic surgeon who was fellowship trained in sports medicine and shoulder surgery at the prestigious Hospital for Special Surgery where he provided care to athletes of all ages. He currently serves as the head team physician for the LA Kings hockey team and associate team physician for USC Athletics. Dr. Petrigliano is a renowned orthopaedic surgeon and researcher who employs state of the art treatments and procedures to get you back to your active life and back to sport. He always treats his patients with compassion and respect. Dr. Petrigliano is located in El Segundo California, and serves greater Los Angeles, Beverly Hills, the South Bay, and the Santa Clarita Valley. Contact Dr. Petrigliano to schedule a consultation today.

At a Glance

Dr. Frank Petrigliano

  • Associate Professor of Orthopaedic Surgery at USC
  • Chief of the Epstein Family Center for Sports Medicine
  • Team physician for the LA Kings and USC Athletics
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