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  • ACL Injuries

    ACL Injuries

    One of the most common knee injuries is an anterior cruciate ligament sprain or tear.

    Athletes who participate in high demand sports like soccer, football, and basketball are more likely to injure their anterior cruciate ligaments(ACL).  If you have injured your ACL, you may require surgery to regain full function of your knee. This will depend on several factors, such as the severity of your injury and your activity level.

    Knee Anatomy

    Three bones meet to form your knee joint: your femur, tibia, and patella. Your patella sits in front of the joint to provide some protection.

    Bones are connected to other bones by ligaments. There are four primary ligaments in your knee. They act like strong ropes to hold the bones together and keep your knee stable.

    Anatomy. Structure knee joint vector

    Injured ligaments are considered “sprains” and are graded on a severity scale.

    Grade 1 Sprains. The ligament is mildly damaged in a Grade 1 Sprain. It has been slightly stretched, but is still able to help keep the knee joint stable.

    Grade 2 Sprains. A Grade 2 Sprain stretches the ligament to the point where it becomes loose. This is often referred to as a partial tear of the ligament.

    Grade 3 Sprains. This type of sprain is most commonly referred to as a complete tear of the ligament. The ligament has been split into two pieces, and the knee joint is unstable.

    Partial tears of the anterior cruciate ligament are rare; most ACL injuries are complete or near complete tears.


    The anterior cruciate ligament can be injured in several ways:

    • Changing direction rapidly
    • Stopping suddenly
    • Slowing down while running
    • Landing from a jump incorrectly
    • Direct contact or collision, such as a football tackle

    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 physical conditioning, muscular strength, and neuromuscular control. Other suggested causes include differences in pelvis and lower extremity alignment, increased looseness in ligaments, and the effects of estrogen on ligament properties.


    When you injure your ACL, you might hear a “popping” noise and you may feel your knee give out from under you. Other typical symptoms include:

    • Pain with swelling. Within 24 hours, your knee will swell. If ignored, the swelling and pain may resolve on its own. However, if you attempt to return to sports, your knee will probably be unstable and you risk causing further damage to the meniscus of your knee.
    • Loss of full range of motion
    • Tenderness along the joint line
    • Discomfort while walking

    Time to visit the Doctor!

    During your first visit, your doctor will talk to you about your symptoms and medical history.  Then during the physical examination, your doctor will check all the structures of your injured knee, and compare them to your non-injured knee. Most ligament injuries can be diagnosed with a thorough physical examination of the knee.


    Treatment for an ACL tear will vary depending upon the patient’s individual needs. For example, the young athlete involved in agility sports will most likely require surgery to safely return to sports. The less active, usually older, individual may be able to return to a quieter lifestyle without surgery.


    •  A torn ACL will not heal without surgery. But nonsurgical treatment may be effective for patients who are elderly or have a very low activity level. If the overall stability of the knee is intact, your doctor may recommend simple, nonsurgical options such as: bracing to protect the knee from instability and physical therapy to decrease swelling and strengthen the muscles around the injured area.

    Surgical Treatment

    • Most ACL tears cannot be stitched back together. To surgically repair the ACL and restore knee stability, the ligament must be reconstructed. Your doctor will replace your torn ligament with a tissue graft. This graft acts as a base for a new ligament to grow on.
    • Grafts can be obtained from several sources. Often they are taken from the patellar tendon, quadriceps tendon and hamstring tendons.  There is also another option, to use a cadaver graft.
    • There are advantages and disadvantages to all graft sources. You should discuss graft choices with your own orthopaedic surgeon to help determine which is best for you.

    Because the regrowth takes time, it may be six months or more before an athlete can return to sports after surgery.


    Whether your treatment involves surgery or not, rehabilitation plays a vital role in getting you back to your daily activities. A physical therapy program will help you regain knee strength and motion.

    If you have surgery, physical therapy first focuses on returning motion to the joint and surrounding muscles. This is followed by a strengthening program designed to protect the new ligament. This strengthening gradually increases the stress across the ligament. The final phase of rehabilitation is sports specific training.