Anterior cruciate ligament
Encyclopedia
The anterior cruciate ligament (ACL) is a cruciate ligament
which is one of the four major ligament
s of the human
knee
. In the quadruped
stifle
(analogous to the knee), based on its anatomical position, it is referred to as the cranial cruciate ligament.
The ACL originates from deep within the notch of the distal femur. Its proximal fibers fan out along the medial wall of the lateral femoral condyle. There are two bundles of the ACL—the anteromedial and the posterolateral, named according to where the bundles insert into the tibial plateau. The ACL attaches in front of the intercondyloid eminence
of the tibia, being blended with the anterior horn of the medial menisucs. These attachments allow it to resist anterior translation and medial rotation of the tibia, in relation to the femur.
, MCL
, and knee cartilage
tears.
, patellar tendon, semitendinosus tendon, gracillus tendon, and the plantaris. There is great controversy as to which source produces the strongest, most stable ACL replacement. Many orthopedic surgeons prefer to use tendons and grafts from cadavers; therefore the patient does not have to rehabilitate more than just their ACL. Others prefer to use tendons directly from the patient in order to counteract the potential for an immune system rejection of the cadaver tissue. Furthermore surgeons have the choice between several surgical techniques to fixate the ACL replacement to the femoral bone: staple fixation, tying sutures over buttons, and screw fixation. There are several studies currently testing all the variables involved in ACL reconstructive surgery accounting for the lifestyle, age, and future goals of the ACL reconstruction patients. There are no quantitative results as to which combination of ligament and grafts work best with the different surgical techniques for every individual.
A 2010 Los Angeles Times review of two seemingly conflicting medical studies discussed whether ACL reconstruction was advisable. One study found that children under 14 who had ACL reconstruction fared better after early surgery than those who underwent a delayed surgery. For adults under 35, though, patients who underwent early surgery followed by rehab fared no better than those who had rehab therapy and a later surgery.
The first report focused on children and the timing of an ACL reconstruction. ACL injuries in children, according to orthopedic surgeon Howard Luks, MD, are a challenge because children have open growth plates in the bottom of the femur or thigh bone and on the top of the tibia or shin. An ACL reconstruction will typically cross the growth plates, posing a theoretical risk of injury to the growth plate, stunting leg growth or causing the leg to grow at an unusual angle.
The second study noted in the L.A. Times piece focused on adults and questioned whether an ACL reconstruction was necessary when an MRI-is not merely an existing tear; many patients without instability, buckling or giving way after a course of rehabilitation can be managed non-operatively. Patients involved in sports requiring significant cutting, pivoting, twisting, or rapid acceleration or deceleration may not be able to participate in these activities without ACL reconstruction, and may want to consider an early reconstruction to minimize the risk of developing common associated injuries. "You can change your knee to suit your lifestyle," says Dr. Howard Luks, "or change your lifestyle to suit your knee."
The randomized control study was also reviewed by the New York Times.
The randomized control study was originally published in the New England Journal of Medicine.
On Tuesday, September 13, 2011, an online article by Jim Dryden, Associate Director of Broadcast Services of the Washington University in St. Louis
Newsroom Record, reviewed a Washington University School of Medicine
study; the examination "looked at why second ACL surgeries often fail":
"Sports medicine specialists at Washington University School of Medicine
in St. Louis are leading a national study analyzing why a second surgery to reconstruct a tear in the knee's anterior cruciate ligament (ACL) carries a high risk of bad outcomes.
More than 200,000 ACL reconstruction surgeries are performed each year in the united States, and 1 percent to 8 percent fail for some reason. Most of those patients then opt to have their knee ligament reconstructed a second time, but the failure rate on those subsequent surgeries is almost 14 percent.
The Washington University group has received a $2.6 million grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases
(one of the constituent institutes of the NIH, or the National Institutes of Health
, which is in turn a part of the Cabinet-level U.S. Department of Health and Human Services, or USDHHS) and is leading dozens of surgeons across the nation in one of the largest orthopedic, multicenter studies ever conducted. The MARS study (Multicenter ACL Revision Study) is comparing surgical techniques and analyzing outcomes for patients undergoing ACL surgery to learn why a subsequent reconstruction is more likely to fail than an initial ACL repair."
Cruciate ligament
Cruciate ligaments are pairs of ligaments arranged like a letter X. They occur in several joints of the body, such as the knee...
which is one of the four major ligament
Ligament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...
s of the human
Human
Humans are the only living species in the Homo genus...
knee
Knee
The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...
. In the quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
stifle
Stifle joint
The stifle joint is a complex joint in the hind limbs of quadruped mammals such as the sheep, horse or dog. It is the equivalent joint to the human knee...
(analogous to the knee), based on its anatomical position, it is referred to as the cranial cruciate ligament.
The ACL originates from deep within the notch of the distal femur. Its proximal fibers fan out along the medial wall of the lateral femoral condyle. There are two bundles of the ACL—the anteromedial and the posterolateral, named according to where the bundles insert into the tibial plateau. The ACL attaches in front of the intercondyloid eminence
Intercondyloid eminence
-Anatomy:Between the articular facets of the proximal tibia, but nearer the posterior than the anterior aspect of the bone, is the intercondyloid eminence , surmounted on either side by a prominent tubercle, on to the sides of which the articular facets are prolonged; in front of and behind the...
of the tibia, being blended with the anterior horn of the medial menisucs. These attachments allow it to resist anterior translation and medial rotation of the tibia, in relation to the femur.
Injury
Anterior cruciate ligament injury is a common knee ligament injury, especially in athletes. Lateral rotational movements in sports like these are what cause the ACL to sprain or tear. sprains can sometimes be fixed through physical therapy and muscle strengthening, though tears almost always require surgery. The most common method for repairing ACL injuries is arthroscopic surgery. Other common injuries accompanying ACL tears are meniscusMeniscus (anatomy)
In anatomy, a meniscus is a crescent-shaped fibrocartilaginous structure that, in contrast to articular disks, only partly divides a joint cavity. In humans it is present in the knee, acromioclavicular, sternoclavicular, and temporomandibular joints; in other organisms they may be present in other...
, MCL
Medial collateral ligament
The medial collateral ligament of the knee is one of the four major ligaments of the knee. It is on the medial side of the knee joint in humans and other primates. It is also known as the tibial collateral ligament, or abbreviated as the MCL.- Structure :It is a broad, flat, membranous band,...
, and knee cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
tears.
Reconstructive surgery
ACL reconstructive surgery can utilize several different tendons and grafts in place of the torn ACL including the hamstringHamstring
In human anatomy, the hamstring refers to any one of the three posterior thigh muscles, or to the tendons that make up the borders of the space behind the knee. In modern anatomical contexts, however, they usually refer to the posterior thigh muscles, or the tendons of the semitendinosus, the...
, patellar tendon, semitendinosus tendon, gracillus tendon, and the plantaris. There is great controversy as to which source produces the strongest, most stable ACL replacement. Many orthopedic surgeons prefer to use tendons and grafts from cadavers; therefore the patient does not have to rehabilitate more than just their ACL. Others prefer to use tendons directly from the patient in order to counteract the potential for an immune system rejection of the cadaver tissue. Furthermore surgeons have the choice between several surgical techniques to fixate the ACL replacement to the femoral bone: staple fixation, tying sutures over buttons, and screw fixation. There are several studies currently testing all the variables involved in ACL reconstructive surgery accounting for the lifestyle, age, and future goals of the ACL reconstruction patients. There are no quantitative results as to which combination of ligament and grafts work best with the different surgical techniques for every individual.
A 2010 Los Angeles Times review of two seemingly conflicting medical studies discussed whether ACL reconstruction was advisable. One study found that children under 14 who had ACL reconstruction fared better after early surgery than those who underwent a delayed surgery. For adults under 35, though, patients who underwent early surgery followed by rehab fared no better than those who had rehab therapy and a later surgery.
The first report focused on children and the timing of an ACL reconstruction. ACL injuries in children, according to orthopedic surgeon Howard Luks, MD, are a challenge because children have open growth plates in the bottom of the femur or thigh bone and on the top of the tibia or shin. An ACL reconstruction will typically cross the growth plates, posing a theoretical risk of injury to the growth plate, stunting leg growth or causing the leg to grow at an unusual angle.
The second study noted in the L.A. Times piece focused on adults and questioned whether an ACL reconstruction was necessary when an MRI-is not merely an existing tear; many patients without instability, buckling or giving way after a course of rehabilitation can be managed non-operatively. Patients involved in sports requiring significant cutting, pivoting, twisting, or rapid acceleration or deceleration may not be able to participate in these activities without ACL reconstruction, and may want to consider an early reconstruction to minimize the risk of developing common associated injuries. "You can change your knee to suit your lifestyle," says Dr. Howard Luks, "or change your lifestyle to suit your knee."
The randomized control study was also reviewed by the New York Times.
The randomized control study was originally published in the New England Journal of Medicine.
On Tuesday, September 13, 2011, an online article by Jim Dryden, Associate Director of Broadcast Services of the Washington University in St. Louis
Washington University in St. Louis
Washington University in St. Louis is a private research university located in suburban St. Louis, Missouri. Founded in 1853, and named for George Washington, the university has students and faculty from all fifty U.S. states and more than 110 nations...
Newsroom Record, reviewed a Washington University School of Medicine
Washington University School of Medicine
Washington University School of Medicine , located in St. Louis, Missouri, is one of the graduate schools of Washington University in St. Louis. One of the top medical schools in the United States, it is currently ranked 4th for research according to U.S. News and World Report and has been listed...
study; the examination "looked at why second ACL surgeries often fail":
"Sports medicine specialists at Washington University School of Medicine
Washington University School of Medicine
Washington University School of Medicine , located in St. Louis, Missouri, is one of the graduate schools of Washington University in St. Louis. One of the top medical schools in the United States, it is currently ranked 4th for research according to U.S. News and World Report and has been listed...
in St. Louis are leading a national study analyzing why a second surgery to reconstruct a tear in the knee's anterior cruciate ligament (ACL) carries a high risk of bad outcomes.
More than 200,000 ACL reconstruction surgeries are performed each year in the united States, and 1 percent to 8 percent fail for some reason. Most of those patients then opt to have their knee ligament reconstructed a second time, but the failure rate on those subsequent surgeries is almost 14 percent.
The Washington University group has received a $2.6 million grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases
National Institute of Arthritis and Musculoskeletal and Skin Diseases
The National Institute of Arthritis and Musculoskeletal and Skin Diseases, or NIAMS, is an institute of the National Institutes of Health, an agency of the United States Department of Health and Human Services...
(one of the constituent institutes of the NIH, or the National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
, which is in turn a part of the Cabinet-level U.S. Department of Health and Human Services, or USDHHS) and is leading dozens of surgeons across the nation in one of the largest orthopedic, multicenter studies ever conducted. The MARS study (Multicenter ACL Revision Study) is comparing surgical techniques and analyzing outcomes for patients undergoing ACL surgery to learn why a subsequent reconstruction is more likely to fail than an initial ACL repair."
See also
- Lateral collateral ligament
- Medial collateral ligamentMedial collateral ligamentThe medial collateral ligament of the knee is one of the four major ligaments of the knee. It is on the medial side of the knee joint in humans and other primates. It is also known as the tibial collateral ligament, or abbreviated as the MCL.- Structure :It is a broad, flat, membranous band,...
- Posterior cruciate ligamentPosterior cruciate ligamentThe posterior cruciate ligament is one of the four major ligaments of the knee. It connects the posterior intercondylar area of the tibia to the medial condyle of the femur...
- Anterior drawer test
- Anterior cruciate ligament reconstructionAnterior cruciate ligament reconstructionAnterior cruciate ligament reconstruction is a surgical tissue graft replacement of the anterior cruciate ligament, located in the knee, to restore its function after anterior cruciate ligament injury. The torn ligament is removed from the knee before the graft is inserted through a hole created...