ACL - WHAT IT IS

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ACL - WHAT IT IS Empty ACL - WHAT IT IS

Post by 112288 Sun Jan 27, 2013 9:19 pm

What is the function of the knee joint?

The purpose of the knee joint is to bend and straighten (flex and extend), allowing the body to change positions. The ability to bend at the knee makes activities like walking and running or standing and sitting much easier and more efficient.

The thighbone (femur) and the shinbone (tibia) meet the kneecap (patella) to form the knee joint. The rounded ends of the femur or condyles line up with the flat tops of the tibia called the plateaus. There are a variety of structures that hold the knee joint stable to allow the condyles and plateaus to maintain their anatomic relationship so that the knee can glide easily through its range of motion.

There are four thick bands of tissue, called ligaments, that stabilize the knee:

The medial collateral ligament (MCL) and the lateral collateral ligament (LCL) stabilize the sides of the knee.
The anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) form an X on the inside of the knee joint and prevent the top and bottom of the knee from sliding back and forth.
The major muscles of the thigh also act as stabilizers: the quadriceps in the front of the leg and the hamstrings in the back.

A sprain occurs when a ligament is injured and the fibers are either stretched or torn.


What is a torn anterior cruciate ligament (ACL)?

The ACL arises from the front of the medial femoral condyle and passes through the middle of the knee to attaches between the bony outcroppings (called the tibia spine) that are located between the tibia plateaus. It is a small structure, less than 1 ½ inches long and ½ inch wide. But regardless of its size, the anterior cruciate ligament is vital in preventing the thighbone (femur) from sliding backward on the tibia (or, from the other point of view, the tibia sliding forward under the femur). The ACL also stabilizes the knee from rotating, the motion that occurs when the foot is planted and the leg pivots.

Without a normal ACL, the knee becomes unstable and can buckle, especially when the leg is planted and attempts are made to stop or turn quickly.


What causes a torn ACL?

Most anterior cruciate ligament injuries occur due to trauma, usually in a sport or fitness activity. The ligament gets stretched or tears when the foot is firmly planted, the knee locks and twists or pivots at the same time. This commonly occurs in basketball, football, soccer, and gymnastics, where a sudden change in direction stresses and damages the ligament. These injuries are usually noncontact, occur at low speed, and occur as the body is decelerating

ACL injuries may also occur when the tibia is pushed forward in relation to the femur. This is the mechanism of injury that occurs because of a fall when skiing, from a direct blow to the front of the knee (such as in football), or in a car accident.

Women are more prone to ACL injuries than men. Women have slightly different anatomy that may put them at higher risk for ACL injuries:

The intercondylar notch at the end of the femur is narrower in women than men. When the knee moves, this narrower space can pinch and weaken the ACL.
Women have a wider pelvis than men and this causes the femur to meet the tibia at a greater angle (called the Q angle). This increases the force applied to the ACL with any twisting motion, increasing the risk of damage.
Women may have a greater imbalance in the strength of the quadriceps muscle in relation to the hamstrings. This increases the stress on the ACL to stabilize the knee and potentially causes it to fail.

What are symptoms and signs of a torn ACL?

With an acute injury, the patient often describes that they heard a loud pop and then developed intense pain in the knee. The pain makes walking or weight-bearing very difficult. The knee joint will begin to swell within a few hours, making it that much harder to try to straighten the knee and walk.

If left untreated, the knee will feel unstable and the patient may complain of recurrent pain and swelling and giving way, especially when walking on uneven ground or climbing up or down steps.


How is a torn ACL diagnosed?

Televised sporting events have allowed the general public to watch how knee injuries occur, often repeatedly in slow-motion replay.

The diagnosis of an ACL injury begins with the care provider taking a history of how the injury occurred. Often the patient can describe in detail their body and leg position and the sequence of events just before, during, and after the injury as well as the angle of any impact.

Physical examination

Physical examination of the knee usually follows a relatively standard pattern.

The knee is examined for obvious swelling, bruising, and deformity.
Areas of tenderness and subtle evidence of knee joint fluid (effusion) are noted.
Most importantly, with knee injury ligamentous, stability is assessed. Since there are four ligaments at risk for injury, the examiner may try to test each to determine which one(s) is (are) potentially damaged.
In the acute situation, with a painful, swollen joint, the initial examination may be difficult because both the pain and the fluid limit the patient's ability to cooperate and relax the leg.
A variety of maneuvers can be used to test the stability and strength of the ACL. These include the Lachmann test, the pivot-shift test, and the anterior drawer test.

The unaffected knee may be examined to be used as comparison.
It may be difficult to examine some patients when muscle strength or spasm can hide an injured ACL because of the knee stabilization that they can provide.

Knee imaging

Plain X-rays of the knee may be done looking for broken bones. Other injuries that may mimic a torn ACL include breakage in the end of the thighbone (such as a tibial plateau fracture or a tibial spine fracture). In patients with an ACL tear, the X-rays are usually normal. Magnetic resonance imaging or MRI has become the test of choice to image the knee looking for ligament injury. In addition to defining the injury, it can help the orthopedic surgeon help decide the best treatment options.

What is the treatment for a torn ACL?

The major decision in treating a torn ACL is whether the patient would benefit from surgery to repair the injury. The surgeon and the patient need to discuss the level of activity that was present before the injury, what the patient expects to do after the injury has healed, the general health of the patient, and whether the patient is willing to undertake the significant physical therapy and rehabilitation required after an operation.

Nonsurgical treatment may be appropriate for patients who are less active, do not participate in activities that require running, jumping or pivoting, and who would be interested in physical therapy to return range of motion and strength to match the uninjured leg.

The anterior cruciate ligament can be reconstructed using arthroscopic surgery. There are a variety of techniques, depending on the type of tear and what other injuries may be associated. The decision as to what surgical option is appropriate is individualized and tailored to a patient's specific situation.

Physical therapy is the mainstay of rehabilitation and therapy regardless of whether or not an operation is performed. The quadriceps and hamstring muscles "shut down" and weaken with any knee injury and strengthening exercises are needed. Return of range of motion is also a key component of therapy.

Medications

Anti-inflammatory medications, such as ibuprofen (Motrin, Advil), naproxen (Aleve), or ketorolac (Toradol), may be suggested to decrease swelling and pain. Narcotic medications for pain, such as codeine, hydrocodone, or oxycodone (Oxycontin), may be prescribed for a short period of time after the acute injury and shortly after surgery.

How long does it take to recover from a torn ACL?

Rehabilitation and return to normal function after surgical repair of an ACL tear can take nine months or more. There needs to be a balance between trying to do too much work in physical therapy returning strength and range of motion and doing too little. Being too aggressive can damage the surgical repair and cause the ligament to fail again. Too little work lengthens the time to return to normal activities.

More than 80% of people who have surgery to repair their ACL have good return of function and lifestyle. Less than 10% of patients develop permanent knee instability.

For patients who do not have surgery to repair a torn ACL, 50% have a fair outcome with no knee instability.


Can ACL tears be prevented?

ACL injuries usually occur in active people engaged in activities that are enjoyable. The risk of injury can be decreased in three ways.

Increase the strength of the muscles of the thigh, especially the hamstrings, and maintaining a balance between the quadriceps and hamstring muscles.

Increase flexibility.

Increase proprioception or the ability to know where the body is in space. Increased agility and balance decreases injury potential. This includes always trying to avoid landing on a fully extended and locked leg.

Torn Anterior Cruciate Ligament (ACL) At A Glance

The anterior cruciate ligament is one of the four ligaments in the knee that provides stabilization.
ACL tear or sprain occurs when a sudden change in direction or pivot occurs on a locked knee.
Initial symptoms of ACL tears include a loud pop that is heard, pain, and swelling.
Arthroscopic surgery is often required to repair the damage to allow return to pre-injury activity. Some patient may choose a nonoperative approach or may not be candidates for surgery.

It may take more than nine months to return to normal activity after an ACL injury.
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Anterior Cruciate Ligament (ACL) Surgery

Surgery for anterior cruciate ligament (ACL) injuries involves reconstructing or repairing the ACL.

ACL reconstruction surgery uses a graft to replace the ligament. The most common grafts are autografts using part of your own body, such as the tendon of the kneecap (patellar tendon) or one of the hamstring tendons. Another choice is allograft tissue, which is taken from a deceased donor.
Repair surgery generally is only used in the case of an avulsion fracture (a separation of the ligament and a piece of the bone from the rest of the bone). In this case, the bone fragment connected to the ACL is reattached to the bone.

ACL surgery is done by making small incisions in the knee and inserting instruments for surgery through these incisions (arthroscopic surgery) or by cutting a large incision in the knee (open surgery).

ACL surgeries are done by orthopedic surgeons.

Arthroscopic surgery

Many orthopedic surgeons use arthroscopic surgery rather than open surgery for ACL injuries because:

It is easy to see and work on the knee structures.
It uses smaller incisions than open surgery.
It can be done at the same time as diagnostic arthroscopy (using arthroscopy to determine the injury or damage to the knee).
It may have fewer risks than open surgery.
Arthroscopic surgery is performed under regional (such as spinal) anesthesia or general anesthesia.

During arthroscopic ACL reconstruction, the surgeon makes several small incisions-usually two or three- around the knee. Sterile saline (salt) solution is pumped into the knee through one incision to expand it and to wash blood from the area. This allows the doctor to see the knee structures more clearly.

The surgeon inserts an arthroscope into one of the other incisions. A camera at the end of the arthroscope transmits pictures from inside the knee to a TV monitor in the operating room.

Surgical drills are inserted through other small incisions. The surgeon drills small holes into the upper and lower leg bones where these bones come close together at the knee joint. The holes form tunnels through which the graft will be anchored.

The surgeon will make another incision in the knee and take the graft (replacement tissue) at this point. If it comes from the tendon at the front of the knee, it will include two small pieces of bone called "bone blocks" on the ends of the tissue. One piece of bone is taken from the kneecap and the other piece is taken from a part of the lower leg bone near the knee joint. If the autograft comes from the hamstring, bone blocks are not taken. The graft may also be taken from a deceased donor (allograft).

The graft is pulled through the two tunnels that were drilled in the upper and lower leg bones. The surgeon secures the graft with hardware such as screws or staples and will close the incisions with stitches or tape. The knee is bandaged, and you are taken to the recovery room for 2 to 3 hours.

During ACL surgery, the surgeon may repair other injured parts of the knee as well, such as ligaments, cartilage, or broken bones.

What To Expect After Surgery

Arthroscopic surgery is often done on an outpatient basis, which means that you do not spend a night in the hospital. Other surgery may require staying in the hospital for a couple of days.


Physical rehabilitation after ACL surgery may take several months to a year. The length of time until you can return to normal activities or sports is different for every person. It may range from 4 to 6 months.3

Why It Is Done

The goal of ACL surgery is to restore normal or almost normal stability in the knee and the level of function you had before the knee injury, limit loss of function in the knee, and prevent injury or degeneration to other knee structures.

Not all ACL tears require surgery.

You may choose to have surgery if you:

Have completely torn your ACL or have a partial tear and your knee is very unstable.
Have gone through a rehab program and your knee is still unstable.
Are very active in sports or have a job that requires knee strength and stability (such as construction work), and you want your knee to be as strong and stable as it was before your injury.
Are willing to complete a long and rigorous rehab program.
Have chronic ACL deficiency that is affecting your quality of life.
Have injured other parts of your knee, such as the cartilage or meniscus, or other knee ligaments or tendons.

You may choose not to have surgery if you:

Have a minor tear in your ACL (a tear that can heal with rest and rehab).
Are not very active in sports and your work does not require a stable knee.
Are willing to stop doing activities that require a stable knee or stop doing them at the same level of intensity. You may choose to substitute other activities that don't require a stable knee, such as cycling or swimming.
Can complete a rehab program that stabilizes your knee and strengthens your leg muscles to reduce the chances that you will injure your knee again and are willing to live with a small amount of knee instability.
Do not feel motivated to complete the long and rigorous rehab program necessary after surgery.
You have medical problems that make surgery too risky.

How Well It Works

After an ACL injury and surgery, the knee is never "normal." But most people regain enough strength and range of motion to return to their usual activities. ACL repair is usually successful for an ACL that has torn away from the upper or lower leg bone (avulsion).

A few people who have ACL surgery still have knee pain and instability and may need another surgery (revision ACL reconstruction). Revision ACL reconstruction is generally not as successful as the initial ACL reconstruction.

Risks

ACL reconstruction surgery is generally safe. Complications that may arise from surgery or during rehabilitation (rehab) and recovery include:

Problems related to the surgery itself. These are uncommon but may include:
Numbness in the surgical scar area.
Infection in the surgical incisions.
Damage to structures, nerves, or blood vessels around and in the knee.
Blood clots in the leg.
The usual risks of anesthesia.
Problems with the graft tendon (loosening, stretching, reinjury, or scar tissue). The screws that attach the graft to the leg bones may cause problems and require removal.
Limited range of motion, usually at the extremes. For example, you may not be able to completely straighten or bend your leg as far as the other leg. This is uncommon, and sometimes another surgery or manipulation under anesthesia can help. Rehab usually attempts to restore a range of motion between 0 degrees (straight) and 130 degrees (bent or flexion). You may lack a few degrees at either end of the range of motion after surgery and rehab.
Grating of the kneecap (crepitus) as it moves against the lower end of the thighbone (femur), which may develop in people who did not have it before surgery. This may be painful and may limit your athletic performance. In rare cases, the kneecap may be fractured while the graft is being taken during surgery or from a fall onto the knee soon after surgery.
Pain, when kneeling, at the site where the tendon graft was taken from the patellar tendon or at the site on the lower leg bone (tibia) where a hamstring or patellar tendon graft is attached.
Repeat injury to the graft (just like the original ligament). Repeat surgery is more complicated and less successful than the first surgery.
What To Think About

In an avulsion fracture, repair surgery is always done as soon as possible.

In reconstruction of a partial or complete tear of the ACL, the best time for surgery is not known. Surgery immediately after the injury has been associated with increased fibrous tissue leading to loss of motion (arthrofibrosis) after surgery.1 Some experts believe that surgery should be delayed until the swelling goes down, you have regained range of motion in your knee, and you can strongly contract (flex) the muscles in the front of your thigh (quadriceps).1 Many experts recommend starting exercises to increase range of motion and regain strength shortly after the injury.

In adults, age is not a factor in surgery, although your overall health may be. Surgery may not be the best treatment for people with medical conditions that make surgery a greater risk. These people may choose nonsurgical treatments and may try to change their activity levels to protect their knees from further injury.

Current research on the surgical treatment of ACL injuries includes different techniques and places to attach grafts; different ways of securing the graft; different types of grafts, such as tendon, muscle, or fascial grafts from your body (autograft); and grafts from a donor (allograft). When choosing a graft, consider the following:

The success of surgery may be more dependent on the surgeon's skill and preference than the type of graft used.

A kneecap tendon graft may result in some pain when kneeling.
The knee functions the same with either a kneecap graft or a hamstring graft.2
A kneecap graft entails more rehab considerations than a hamstring graft, such as increased pain and swelling that may limit exercises for the thigh muscles for a while.

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