ACL - Causes and Symptoms

Anterior Cruciate Ligament (ACL) Injuries – Causes

Anterior cruciate ligament (ACL) injuries are caused when the knee is straightened beyond its normal limits (hyperextended), twisted, or bent side to side.

Typical situations that can lead to ACL injuries include:

Changing direction quickly or cutting around an obstacle or another player with one foot solidly planted on the ground. (This can happen in sports that put high demand on the ACL, such as basketball, football, soccer, skiing, and gymnastics.)

Landing after a jump with a sudden slowing down, especially if the leg is straight or slightly bent (such as in basketball).

Falling off a ladder, stepping off a curb, jumping from a moderate or extreme height, stepping into a hole, or missing a step when walking down a staircase. Injuries like these tend to be caused by stopping suddenly, with the leg straight or slightly bent.

Inactive people and some older adults who have weak leg muscles may injure their knees during normal daily activities. But they usually injure bones, not ligaments.

When contact causes an ACL injury, it can be from playing a sport, from a sudden and severe accident, or from less obvious contact injuries.

Symptoms

Symptoms of a severe and sudden (acute) anterior cruciate ligament (ACL) injury include:

●  Feeling or hearing a "pop" in the knee at the time of injury.

●  Sudden instability in the knee. (The knee feels wobbly, buckles, or gives
    out.) This may happen after a jump or change in direction or after a direct
    blow to the side of the knee.

●  Pain on the outside and back of the knee.

●  Knee swelling within the first few hours of the injury. This may be a sign of
    bleeding inside the joint. Swelling that occurs suddenly is usually a sign of a
    serious knee injury.

●  Limited knee movement because of swelling and/or pain.

After an acute injury, you will almost always have to stop the activity you are doing, but you may be able to walk.

Other health problems can cause symptoms like those of an ACL injury. They include a bone break or injuries to the knee cushions (menisci) or to other ligaments in the knee.

Chronic ACL deficiency

The main symptom of chronic (long-lasting and recurrent) ACL deficiency is an unstable knee joint. The knee buckles or gives out, sometimes with pain and swelling. This happens more often over time. But not everyone with an ACL injury develops a chronic ACL deficiency.

What Happens

If you have a sudden (acute) anterior cruciate ligament (ACL) injury, you typically know when it happens. You may feel or hear a pop, and the knee may give out, causing you to fall. The knee swells and often is too painful or unstable for you to continue any activity.

An ACL injury can cause small or medium tears of the ligament, a complete tear of the ligament (rupture), a separation of the ligament from the upper or lower leg bone (avulsion), or a separation of the ligament and part of the bone from the rest of the bone (avulsion fracture). When any of these occur, the lower leg bone moves abnormally forward on the upper bone, with a sense of the knee giving out or buckling.

How an anterior cruciate ligament (ACL) injury is treated and how it heals depends on:

●  The condition of the ACL before the injury. This includes prior injuries,
    partial tears, ACL deficiency, and changes due to age.

●  The general condition and health of the rest of your knee before this injury.

●  The amount of damage or injury to the ACL. Injuries are usually grouped
    into grade I, II, or III sprains (tears) according to the amount of damage.

●  Other injuries to the knee joint, such as to the cartilage camera.gif or
    menisci camera.gif, or to bones in the knee.

●  Your age, how active you are, and how committed you are to treatment and
    rehabilitation (rehab).

●  The time of diagnosis. If the ACL diagnosis is not made soon after the injury,
    the knee may be further damaged with use.

An ACL injury may develop into long-lasting and recurrent (chronic) ACL deficiency that leads to an unstable knee—the knee buckles or gives out, sometimes with pain and swelling. This can occur if you had an ACL injury in the past and didn't know it or if your ACL has not been treated or has been treated unsuccessfully. ACL deficiency can cause damage to the joint, including osteoarthritis. But not everyone with an ACL injury gets ACL deficiency.

People with minor ACL injuries usually begin treatment with a physical rehab program. Rehab exercises build strength and flexibility in the muscles on the front of the thigh (quadriceps) and strengthen and tighten the muscles in the back of the thigh (hamstrings). Most people return to their normal activities after a few weeks of rehab.

More serious ACL injuries may need several months of rehab or surgery followed by several months of rehab to regain your knee strength, knee stability, and range of motion.

Not all ACL injuries require surgery. But whether you have surgery or not, you need to start strengthening your knee and regaining motion soon after you injure it. This prepares you for your rehab program if you choose not to have surgery. It also helps prepare the knee for surgery if you choose to have it.

What Increases Your Risk

Things that increase your risk of anterior cruciate ligament (ACL) injuries include:

●  Playing sports that involve sudden changes in direction or cutting around
    other players or obstacles, such as skiing, football, soccer, basketball,
    baseball, and tennis.

●  Making accidental movements that may twist your knee. Examples include
    falling off a ladder, jumping from an extreme height, stepping into a hole, or
    missing a step on a staircase.

●  Losing muscle tone in legs (from aging or inactivity).

●  Having unbalanced leg muscle strength, such as if the muscles in the front
    of your thigh (quadriceps) are stronger than the muscles at the back of your
    thigh (hamstrings).

●  Previous ACL injuries, especially if your knee sometimes gives out or
    buckles (chronic ACL deficiency).

When To Call a Doctor

if you have an injury to your knee and:

●  You have severe pain in your knee.

●  Your knee appears to be deformed.

●  You have signs of damage to the nerves or blood vessels. Signs include
    numbness, tingling, a "pins-and-needles" sensation below the injury, an
    inability to move your leg below the injury, pale or bluish skin, or your leg
    feels cold.

●  You have severe swelling in your knee right after the injury.

Call your doctor today if:

●  Your knee begins to swell within 2 hours of the injury.

●  You hear or feel a pop in your knee during an injury.

●  Your knee won't bear weight.

●  You are unable to straighten your leg completely.

●  Your knee is unstable, buckles, or gives out.

●  Your knee "locks" in one position.

●  You have had an anterior cruciate ligament (ACL) injury in the past, and you
    have reinjured your knee.

Before your appointment, don't put weight on the injured knee. Use crutches if you need to. Apply ice and wrap your knee in an elastic bandage or neoprene (synthetic rubber) sleeve. Rest and elevate the knee. Take a nonsteroidal anti-inflammatory drug, such as ibuprofen (Advil) or naproxen (Aleve), to reduce swelling. For more information on first aid steps, see Home Treatment.

Watchful waiting

Watchful waiting is a period of time during which you and your doctor observe your symptoms or condition without using medical treatment. Watchful waiting is not appropriate if knee pain is severe; if your knee is deformed, swells, or has limited movement immediately after an injury; or if you are unable to bear any weight because of either pain or instability.

Serious knee injuries need to be checked for possible broken bones as well as ligament or cartilage camera.gif damage. Whenever immediate swelling follows an injury, there also may be torn blood vessels or damaged nerves in the knee. Your doctor will check your knee to make sure the blood supply to your leg is normal and the nerves are intact.

If you have occasional pain in your knee or your knee sometimes gives way or buckles, have your doctor check it. If you have damaged your ACL, it is important to get treatment so that your knee is appropriately managed. This may reduce the chance that you will get osteoarthritis in your knee.

Who to see

Knee problems can be diagnosed by:

●  Emergency medicine specialists (for acute knee injury).

●  Family medicine doctors familiar with knee injuries.

●  Orthopedic surgeons.

●  Sports medicine specialists.

If surgery is considered, you may be referred to an orthopedic surgeon (possibly a sports medicine specialist) who is experienced in knee surgery.

Exams and Tests

An anterior cruciate ligament (ACL) injury is diagnosed through a medical history and a physical exam. A doctor who specializes in knee injuries (for example, an orthopedic surgeon or sports medicine specialist) will usually be able to accurately diagnose an ACL injury after:

●  Taking your medical history. You will be asked how you injured your knee,
    about your symptoms at the time of injury, whether you have had any other
    knee injuries, and general questions about your health.

●  Checking your knees for stability, strength, range of movement, swelling,
    and tenderness. Tests for stability include a Lachman test and a pivot shift
    test. The Lachman test compares the degree of looseness (laxity) in your
    knees.

●  Looking at an X-ray, which is usually done for any knee injury if there is
    pain, swelling, or you cannot put your weight on the leg. Although an ACL
    injury cannot be directly diagnosed by an X-ray, an X-ray can show whether
    a bone is broken, any bone fragments are in the knee, the ACL is torn from
    the bone (avulsion), or blood is present in the knee (effusion).

If you see your doctor soon after your injury, the pain and the degree of swelling and muscle tenseness may make it difficult for your doctor to accurately diagnose the condition.

More imaging tests

Other tests that may help your doctor see how badly the knee is injured include:

●  An MRI. It can identify an ACL tear or other problems, such as meniscus
    tears or other ligament injuries.

●  A CT scan. It can be done to see any small breaks in the bones.

Looking at fluid in the knee

If your knee looks red, feels warm to the touch, or is very swollen, a knee joint aspiration (arthrocentesis) may be done. This involves removing fluid from the knee joint with a needle. It is done to:

●  Help relieve pain and pressure. This may make the physical exam easier
    and make you more comfortable.

●  Check joint fluid for possible infection or inflammation.

●  Look for blood, which may mean there is a tear.

●  Look for drops of fat, which may mean there is a broken bone.

Local anesthetic may be injected to reduce pain and make the knee easier to examine.

Other tests

Arthrometric testing: In this test, your doctor uses a tool to measure the looseness of your knee. This test is especially useful in people whose pain or size makes a physical exam difficult. An arthrometer has two sensor pads and a pressure handle that allows your doctor to put force on the knee.

ArthroscopyArthroscopy: This can be used to diagnose an ACL injury and as a method of surgery. It involves inserting tools through one or more small incisions in the knee, which allows your doctor to examine the structures inside the knee joint, including the ACL.

Before arthroscopy, you and your doctor will decide what will be done if certain conditions are found. For example, you may decide in advance that if a complete tear of the ACL is found, it will be reconstructed during the arthroscopy. Or if a more severe condition is found, you and your doctor may agree to discuss the condition rather than proceeding with surgery at that time.

Source: http://www.webmd.com/