Anterior cruciate ligament injury
Encyclopedia
An injury to the anterior cruciate ligament
can be a debilitating musculoskeletal injury to the knee
, seen most often in athletes. Non-contact tears and ruptures are the most common causes of ACL injury.
The anterior cruciate ligament (ACL) is an important ligament for proper movement. ACL injury more commonly causes knee instability than does injury to other knee ligaments. Injuries of the ACL range from mild such as small tears to severe when the ligament is completely torn. There are many ways the ACL can be torn; the most prevalent is when the knee is bent too much toward the back and when it goes too far to the side. Tears in the anterior cruciate ligament often take place when the knee receives a direct impact from the front while the leg is in a stable position, for example a standing football player is tackled sideways when his feet are firmly planted. Torn ACL’s are most often related to high impact sports or when the knee is forced to make sharp changes in movement and during abrupt stops from high speed. These types of injuries are prevalent in Alpine skiing, American football
, Australian rules football
, Soccer, rugby
, martial arts
, and football
. Research has shown that women involved in sports are more likely to have ACL injuries than men. ACL tears can also happen in older individuals through slips and falls and are seen mostly in people over forty due to wear and tear of the ligaments. An ACL tear can be determined by an individual if a popping sound is heard after impact, swelling after a couple of hours, severe pain when bending the knee, and when the knee buckles or locks during movement or gives way while standing still with weight on the affected knee.
damage, leading to an increased risk of developing osteoarthritis
later in life.
Women in sports such as football
, basketball
, tennis
and volleyball
are significantly more prone to ACL injuries than men. The discrepancy has been attributed to differences between the sexes in anatomy
, general muscular strength, reaction time of muscle contraction and coordination, and training techniques. A recent study suggests hormone
-induced changes in muscle tension associated with menstrual cycle
s may also be an important factor. Women have a relatively wider pelvis
, requiring the femur
to angle toward the knees. Recent research also suggests that there may be a gene variant that increases the risk of injury
The majority of ACL injuries occur in athletes landing flat on their heels. The latter directs the forces directly up the tibia into the knee, while the straight-knee position places the lateral femoral condyle on the back-slanted portion of the tibia. The resultant forward slide of the tibia
relative to the femur is restrained primarily by the now-vulnerable ACL.
, anterior drawer test
and the Lachman test are used during the clinical examination of suspected ACL injury. The ACL can also be visualized using a magnetic resonance imaging scan (MRI scan).
An ACL tear can be determined by the individual if a popping sound is heard after impact, swelling after a couple of hours, severe pain when bending the knee, and when the knee buckles or locks during movement.
Though clinical examination in experienced hands is highly accurate, the diagnosis is usually confirmed by MRI, which has greatly lessened the need for diagnostic arthroscopy
. MRI has a higher accuracy than clinical examination in detecting ACL tears when multiple ligaments are torn. This is of particular benefit if there is a coexisting posterolateral corner injury. Addressing the posterolateral corner injury at the time of ACL reconstruction
will prevent premature graft failure.
. It can be used to help diagnose sprain and tears.
The test is performed as follows: the patient is positioned lying supine
with the hip flexed to 45° and the knee to 90°. The examiner positions themselves by sitting on the examination table in front of the involved knee and grasping the tibia
just below the joint line of the knee. The thumbs are placed along the joint line on either side of the patellar tendon. The index fingers are used to palpate the hamstring tendons to ensure that they are relaxed; the hamstring
muscle group must be relaxed to ensure a proper test. The tibia is then drawn forward anteriorly. An increased amount of anterior tibial translation compared with the opposite limb or lack of a firm end-point indicates either a sprain of the anteromedial bundle of the ACL or a complete tear of the ACL. This test should be performed along with other ACL-specific tests to help obtain a proper diagnosis.
The Lachman test is an orthopedic test used for examining the anterior cruciate ligament
(ACL) in the knee
for patients where there is a suspicion of a torn ACL.
The Lachman test is recognized by most authorities as the most reliable and sensitive clinical test for the determination of anterior cruciate ligament integrity, superior to the anterior drawer test commonly used in the past.
To do this, lay the patient supine
on an examination table. Put the patient's knee in about 20-30 degrees flexion
, also according to Bates' Guide to Physical Examination the leg should be externally rotated. The examiner should place one hand behind the tibia
and the other on the patient's thigh. It is important that the examiner's thumb be on the tibial tuberosity. On pulling anteriorly on the tibia
, an intact ACL should prevent forward translational movement of the tibia on the femur
("firm endpoint").
Anterior translation of the tibia associated with a soft or a mushy endpoint indicates a positive test. More than about 2 mm of anterior translation compared to the uninvolved knee suggests a torn ACL ("soft endpoint"), as does 10 mm of total anterior translation. An instrument called a "KT-1000" can be used to determine the magnitude of movement in mm.
This test can be done in an on-the-field evaluation in an acute injury setting, or in a clinical setting when a patient presents with knee pain. In either situation, ruling out fracture is important in the evaluation process. Also when evaluating the integrity of the ACL, it is important to test the integrity of the MCL, because this is a common ligament torn in an ACL injury as well. This test is named after orthopaedic surgeon
, John Lachman, the late Chairman of the Department of Orthopaedic Surgery and Sports Medicine at Temple University School of Medicine in Philadelphia, PA. The original publication describing the test was submitted by one of his colleagues, Dr. Joseph Torg.
The term for non-surgical treatment for ACL rupture is "conservative management", and it often includes physical therapy
and using a knee brace. Lack of an ACL increases the risk of other knee injuries such as a torn meniscus
, so sports with cutting and twisting motions are strongly discouraged. For patients who frequently participate in such sports, surgery
is often indicated.
Patients who have suffered an ACL injury should always be evaluated for other knee injuries that often occur in combination with an ACL tear. These include cartilage/meniscus injuries, bone bruises, PCL tears, posterolateral injuries and collateral ligament injuries.
There are two main options for ACL graft
selection, allograft and autograft. Autografts are the persons own tissues, and options include the hamstring
tendon
s or middle third of the patella tendon but it is not known which is best. Allograft is cadaver
ic tissue sourced from a tissue bank
. Each method has its own advantages and disadvantages; hamstring and middle third of patella tendon having similar outcomes. Patellar grafts are often incorrectly cited as being stronger, but the site of the harvest is often extremely painful for weeks after surgery and some patients develop chronic patellar tendinitis. Replacement via a posthumous donor involves a slightly higher risk of infection. Additionally, donor grafts eliminate tendon harvesting which, due to improved arthroscopic methods, is responsible for most post-operative pain.
The surgery is typically undertaken arthroscopically, with tunnels drilled into the femur
and tibia
at approximately the original ACL attachments. The graft is then placed into position and held in place. There are a variety of fixation devices available, particularly for hamstring tendon fixation. These include screws, buttons and post fixation devices. The graft typically attaches to the bone within six to eight weeks. The original collagen
tissue in the graft acts as a scaffold and new collagen tissue is laid down in the graft with time. Hence the graft takes over six months to reach maximal strength.
After surgery, the knee joint loses flexibility, and the muscle
s around the knee and in the thigh tend to atrophy
. All treatment options require extensive physical therapy
to regain muscle strength around the knee and restore range of motion
(ROM). For some patients, the lengthy rehabilitation period may be more difficult to deal with than the actual surgery. In general, a rehabilitation period of six months to a year is required to regain pre-surgery strength and use. This is very dependent on the rehabilitation assignment provided by the surgeon as well as the person who is receiving the surgery. External bracing is recommended for athletes in contact and collision sports for a period of time after reconstruction. It is important however to realize that this type of prevention is given by a 'surgeon to surgeon' basis; all surgeons will prescribe a brace and crutches for post surgery recovery. Total usage time is one month. After surgery, no sports are allowed for 6 to 7 months. Whether the ACL deficient knee is reconstructed or not, the patient is susceptible to early onset of chronic degenerative joint disease
.
Phase 1:
This step is called the early rehabilitation phase. This is basically the things that were covered in short term, things to reduce pain and swelling while gaining movement.
Phase 2:
This phase covers weeks 3 and 4. At this point the pain should be subsiding and the patient will be ready to try more things that their knee isn’t willing to perform. That is why there is a lot of emphasis put on joint protection during this step. The patient will be able to start doing exercises such as mini wall sits and riding stationary bikes. The aim of this is to be able to bend the knee 100 degrees.
Phase 3:
This phase is known as the controlled ambulation phase and it covers weeks 4 to 6. At this point the patient will be doing the same exercises from phase 2 plus some more challenging ones. The patient will try to get their knee to bend 130 degrees during this stage. The aim during this period is to focus heavily on improving balance.
Phase 4:
This is the moderate protection phase and it covers weeks 6 to 8. In this period the patient will try to obtain full range of motion as well as increase resistance for the workouts.
Phase 5:
This is the light activity phase and it covers weeks 8 to 10. This period will place particular emphasis on strengthening exercises, with increased concentration on balance and mobility.
Phase 6:
This is the return to activity phase and it lasts from week 10 until the target activity level is reached. At this point the patient will be able to start jogging and performing moderately intense agility drills. Somewhere between month 3 and month 6 the surgeon will probably request that the patient perform physical tests so s/he can monitor the activity level. When the doctor feels comfortable with the progress of the patient, s/he will clear that person to resume a fully active lifestyle.
A notable finding is that women are three times more likely to have an ACL injury than men, due to variations of hormone levels and greater ligament strength in men than in women. Most importantly, there is substantial difference in neuromuscular coordination and control in landing—women have less hip and knee flexion. Women also have wider cue angles than men, and this combined with their weakened hip strength makes them more prone to an ACL tear. You especially see this with Women's Basketball and Volleyball. Athletic trainers and team physicians advise female athletes to adapt an ACL conditioning program.
Anterior cruciate ligament
The anterior cruciate ligament is a cruciate ligament which is one of the four major ligaments of the human knee. In the quadruped stifle , 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...
can be a debilitating musculoskeletal injury to the 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...
, seen most often in athletes. Non-contact tears and ruptures are the most common causes of ACL injury.
The anterior cruciate ligament (ACL) is an important ligament for proper movement. ACL injury more commonly causes knee instability than does injury to other knee ligaments. Injuries of the ACL range from mild such as small tears to severe when the ligament is completely torn. There are many ways the ACL can be torn; the most prevalent is when the knee is bent too much toward the back and when it goes too far to the side. Tears in the anterior cruciate ligament often take place when the knee receives a direct impact from the front while the leg is in a stable position, for example a standing football player is tackled sideways when his feet are firmly planted. Torn ACL’s are most often related to high impact sports or when the knee is forced to make sharp changes in movement and during abrupt stops from high speed. These types of injuries are prevalent in Alpine skiing, American football
American football
American football is a sport played between two teams of eleven with the objective of scoring points by advancing the ball into the opposing team's end zone. Known in the United States simply as football, it may also be referred to informally as gridiron football. The ball can be advanced by...
, Australian rules football
Australian rules football
Australian rules football, officially known as Australian football, also called football, Aussie rules or footy is a sport played between two teams of 22 players on either...
, Soccer, rugby
Rugby football
Rugby football is a style of football named after Rugby School in the United Kingdom. It is seen most prominently in two current sports, rugby league and rugby union.-History:...
, martial arts
Martial arts
Martial arts are extensive systems of codified practices and traditions of combat, practiced for a variety of reasons, including self-defense, competition, physical health and fitness, as well as mental and spiritual development....
, and football
Football
Football may refer to one of a number of team sports which all involve, to varying degrees, kicking a ball with the foot to score a goal. The most popular of these sports worldwide is association football, more commonly known as just "football" or "soccer"...
. Research has shown that women involved in sports are more likely to have ACL injuries than men. ACL tears can also happen in older individuals through slips and falls and are seen mostly in people over forty due to wear and tear of the ligaments. An ACL tear can be determined by an individual if a popping sound is heard after impact, swelling after a couple of hours, severe pain when bending the knee, and when the knee buckles or locks during movement or gives way while standing still with weight on the affected knee.
Signs and symptoms
Symptoms of an ACL injury include hearing a sudden popping sound, swelling, and instability of the knee (i.e., a "wobbly" feeling). Pain is also a major symptom in an ACL injury and can range from moderate to severe. Continued athletic activity on a knee with an ACL injury can have devastating consequences, resulting in massive cartilageCartilage
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...
damage, leading to an increased risk of developing osteoarthritis
Osteoarthritis
Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...
later in life.
Causes
ACL injuries occur when an athlete rapidly decelerates, followed by a sharp or sudden change in direction (cutting). ACL failure has been linked to heavy or stiff-legged landing; as well as twisting or turning the knee while landing, especially when the knee is in the valgus (knock-knee) position.Women in sports such as football
Football
Football may refer to one of a number of team sports which all involve, to varying degrees, kicking a ball with the foot to score a goal. The most popular of these sports worldwide is association football, more commonly known as just "football" or "soccer"...
, basketball
Basketball
Basketball is a team sport in which two teams of five players try to score points by throwing or "shooting" a ball through the top of a basketball hoop while following a set of rules...
, tennis
Tennis
Tennis is a sport usually played between two players or between two teams of two players each . Each player uses a racket that is strung to strike a hollow rubber ball covered with felt over a net into the opponent's court. Tennis is an Olympic sport and is played at all levels of society at all...
and volleyball
Volleyball
Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules.The complete rules are extensive...
are significantly more prone to ACL injuries than men. The discrepancy has been attributed to differences between the sexes in anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
, general muscular strength, reaction time of muscle contraction and coordination, and training techniques. A recent study suggests hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
-induced changes in muscle tension associated with menstrual cycle
Menstrual cycle
The menstrual cycle is the scientific term for the physiological changes that can occur in fertile women for the purpose of sexual reproduction. This article focuses on the human menstrual cycle....
s may also be an important factor. Women have a relatively wider pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
, requiring the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
to angle toward the knees. Recent research also suggests that there may be a gene variant that increases the risk of injury
The majority of ACL injuries occur in athletes landing flat on their heels. The latter directs the forces directly up the tibia into the knee, while the straight-knee position places the lateral femoral condyle on the back-slanted portion of the tibia. The resultant forward slide of the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
relative to the femur is restrained primarily by the now-vulnerable ACL.
Diagnosis
The pivot-shift testPivot-shift test
Lateral Pivot Shift Test for Anterolateral Knee Instability. This test can be used to evaluate the anterolateral structures of the knee for sprains....
, anterior drawer test
Drawer test
The drawer test is a test used by physicians to detect rupture of the cruciate ligaments in the knee. The patient should be supine with the hips flexed to 45 degrees, the knees flexed to 90 degrees and the feet flat on table. The examiner sits on the patient's feet and grasps the patient's tibia...
and the Lachman test are used during the clinical examination of suspected ACL injury. The ACL can also be visualized using a magnetic resonance imaging scan (MRI scan).
An ACL tear can be determined by the individual if a popping sound is heard after impact, swelling after a couple of hours, severe pain when bending the knee, and when the knee buckles or locks during movement.
Though clinical examination in experienced hands is highly accurate, the diagnosis is usually confirmed by MRI, which has greatly lessened the need for diagnostic arthroscopy
Arthroscopy
Arthroscopy is a minimally invasive surgical procedure in which an examination and sometimes treatment of damage of the interior of a joint is performed using an arthroscope, a type of endoscope that is inserted into the joint through a small incision...
. MRI has a higher accuracy than clinical examination in detecting ACL tears when multiple ligaments are torn. This is of particular benefit if there is a coexisting posterolateral corner injury. Addressing the posterolateral corner injury at the time of ACL reconstruction
Anterior cruciate ligament reconstruction
Anterior 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...
will prevent premature graft failure.
Anterior drawer test
The anterior drawer test for anterior cruciate ligament laxity is one of many medical tests used to determine the integrity of the anterior cruciate ligamentAnterior cruciate ligament
The anterior cruciate ligament is a cruciate ligament which is one of the four major ligaments of the human knee. In the quadruped stifle , 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...
. It can be used to help diagnose sprain and tears.
The test is performed as follows: the patient is positioned lying supine
Supine position
The supine position is a position of the body: lying down with the face up, as opposed to the prone position, which is face down, sometimes with the hands behind the head or neck. When used in surgical procedures, it allows access to the peritoneal, thoracic and pericardial regions; as well as the...
with the hip flexed to 45° and the knee to 90°. The examiner positions themselves by sitting on the examination table in front of the involved knee and grasping the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
just below the joint line of the knee. The thumbs are placed along the joint line on either side of the patellar tendon. The index fingers are used to palpate the hamstring tendons to ensure that they are relaxed; the hamstring
Hamstring
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...
muscle group must be relaxed to ensure a proper test. The tibia is then drawn forward anteriorly. An increased amount of anterior tibial translation compared with the opposite limb or lack of a firm end-point indicates either a sprain of the anteromedial bundle of the ACL or a complete tear of the ACL. This test should be performed along with other ACL-specific tests to help obtain a proper diagnosis.
Lachman test
- The knee is flexed at 30 degrees
- Examiner pulls on the tibia to assess the amount of anterior motion of the tibia in comparison to the femur
- An ACL-deficient knee will demonstrate increased forward translation of the tibia at the conclusion of the movement
The Lachman test is an orthopedic test used for examining the anterior cruciate ligament
Anterior cruciate ligament
The anterior cruciate ligament is a cruciate ligament which is one of the four major ligaments of the human knee. In the quadruped stifle , 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...
(ACL) in the 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...
for patients where there is a suspicion of a torn ACL.
The Lachman test is recognized by most authorities as the most reliable and sensitive clinical test for the determination of anterior cruciate ligament integrity, superior to the anterior drawer test commonly used in the past.
To do this, lay the patient supine
Supine position
The supine position is a position of the body: lying down with the face up, as opposed to the prone position, which is face down, sometimes with the hands behind the head or neck. When used in surgical procedures, it allows access to the peritoneal, thoracic and pericardial regions; as well as the...
on an examination table. Put the patient's knee in about 20-30 degrees flexion
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
, also according to Bates' Guide to Physical Examination the leg should be externally rotated. The examiner should place one hand behind the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
and the other on the patient's thigh. It is important that the examiner's thumb be on the tibial tuberosity. On pulling anteriorly on the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
, an intact ACL should prevent forward translational movement of the tibia on the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
("firm endpoint").
Anterior translation of the tibia associated with a soft or a mushy endpoint indicates a positive test. More than about 2 mm of anterior translation compared to the uninvolved knee suggests a torn ACL ("soft endpoint"), as does 10 mm of total anterior translation. An instrument called a "KT-1000" can be used to determine the magnitude of movement in mm.
This test can be done in an on-the-field evaluation in an acute injury setting, or in a clinical setting when a patient presents with knee pain. In either situation, ruling out fracture is important in the evaluation process. Also when evaluating the integrity of the ACL, it is important to test the integrity of the MCL, because this is a common ligament torn in an ACL injury as well. This test is named after orthopaedic surgeon
Orthopedic surgery
Orthopedic surgery or orthopedics is the branch of surgery concerned with conditions involving the musculoskeletal system...
, John Lachman, the late Chairman of the Department of Orthopaedic Surgery and Sports Medicine at Temple University School of Medicine in Philadelphia, PA. The original publication describing the test was submitted by one of his colleagues, Dr. Joseph Torg.
Pivot shift test
- Person lies on one side of the body
- Knee is extended and internally rotated
- Doctor applies stress to lateral side of the knee, while the knee is being flexed
- A crash felt at 30 degrees flexion indicates positive test.
Prevention
Research has shown that the incidence of non-contact ACL injury can be reduced anywhere from 20% to 80% by engaging in regular neuromuscular training that is designed to enhance proprioception, balance, proper movement patterns and muscle strength.Treatment
The ACL primarily serves to stabilize the knee in an extended position and when surrounding muscles are relaxed; so if the muscles are strong, many people can function without it. Fluids will also build the muscle.The term for non-surgical treatment for ACL rupture is "conservative management", and it often includes physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
and using a knee brace. Lack of an ACL increases the risk of other knee injuries such as a torn meniscus
Meniscus (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...
, so sports with cutting and twisting motions are strongly discouraged. For patients who frequently participate in such sports, surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
is often indicated.
Patients who have suffered an ACL injury should always be evaluated for other knee injuries that often occur in combination with an ACL tear. These include cartilage/meniscus injuries, bone bruises, PCL tears, posterolateral injuries and collateral ligament injuries.
Conservative
A torn ACL is less likely to restrict the movement of the knee. When tears to the ACL are not repaired it can sometimes cause damage to the cartilage inside the knee because with the torn ACL the tibia and femur bone are more likely to rub against each other. Immediately after the tear of the ACL, the person should rest it, ice it every fifteen to twenty minutes, produce compression on the knee, and then elevate above the heart; this process helps decrease the swelling and reduce the pain. The form of treatment is determined based on the severity of the tear on the ligament. Small tears in the ACL may just require several months of rehab in order to strengthen the surrounding muscles, the hamstring and the quadriceps, so that these muscles can compensate for the torn ligament.Surgery
If the tear is severe, surgery may be necessary because the ACL can not heal independently because there is a lack of blood supply going to this ligament. Surgery is usually required among athletes because the ACL is needed in order to perform sharp movements safely and with stability. The surgery of the ACL is usually done several weeks after the injury in order to allow the swelling and inflammation to go down. During surgery the ACL is not repaired instead, it is reconstructed using other ligaments in the body. There are three different types of ACL surgery. Patella tendon-bone auto graft and hamstring auto graft are the most common and preferred and tend to produce the best results. For the Patella tendon-bone auto graft, the central 1/3 of the patella tendon is removed along with a piece of bone at the attachment sites on the kneecap and tibia. The advantages of using this method is that the patella tendon and ACL are relatively the same length and it uses a bone to bone attachment which most surgeons agree is much stronger than other healing methods. Disadvantages of this method is common anterior knee pain due to the removal of bone from the kneecap. For the hamstring auto graft, two tendons are taken from the hamstring muscles and wrapped together forming the new ACL. Advantages of this method are less pain associated with post surgery healing than that of the patella tendon-bone graft due to the fact no bone was removed and the incision is small. Disadvantages of this method is that it takes longer to heal since there is no bone to bone healing and the tendon to bone takes awhile to become rigid. After the surgery, rehabilitation is required in order to strengthen the surrounding muscles and stabilize the joint.There are two main options for ACL graft
Medical grafting
Grafting refers to a surgical procedure to move tissue from one site to another on the body, or from another person, without bringing its own blood supply with it. Instead, a new blood supply grows in after it is placed. A similar technique where tissue is transferred with the blood supply intact...
selection, allograft and autograft. Autografts are the persons own tissues, and options include the hamstring
Hamstring
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...
tendon
Tendon
A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments and fasciae as they are all made of collagen except that ligaments join one bone to another bone, and fasciae connect muscles to other...
s or middle third of the patella tendon but it is not known which is best. Allograft is cadaver
Cadaver
A cadaver is a dead human body.Cadaver may also refer to:* Cadaver tomb, tomb featuring an effigy in the form of a decomposing body* Cadaver , a video game* cadaver A command-line WebDAV client for Unix....
ic tissue sourced from a tissue bank
Tissue bank
A Tissue Bank, as used in this article, is a term most commonly used to describe an establishment that collects and harvests human cadaver tissue for the purposes of medical research and education....
. Each method has its own advantages and disadvantages; hamstring and middle third of patella tendon having similar outcomes. Patellar grafts are often incorrectly cited as being stronger, but the site of the harvest is often extremely painful for weeks after surgery and some patients develop chronic patellar tendinitis. Replacement via a posthumous donor involves a slightly higher risk of infection. Additionally, donor grafts eliminate tendon harvesting which, due to improved arthroscopic methods, is responsible for most post-operative pain.
The surgery is typically undertaken arthroscopically, with tunnels drilled into the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
and tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
at approximately the original ACL attachments. The graft is then placed into position and held in place. There are a variety of fixation devices available, particularly for hamstring tendon fixation. These include screws, buttons and post fixation devices. The graft typically attaches to the bone within six to eight weeks. The original collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
tissue in the graft acts as a scaffold and new collagen tissue is laid down in the graft with time. Hence the graft takes over six months to reach maximal strength.
After surgery, the knee joint loses flexibility, and the muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s around the knee and in the thigh tend to atrophy
Atrophy
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
. All treatment options require extensive physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
to regain muscle strength around the knee and restore range of motion
Range of motion
Range of motion , is the distance that a movable object may normally travel while properly attached to another object. It is also called range of travel, particularly when talking about mechanical devices and in mechanical engineering fields...
(ROM). For some patients, the lengthy rehabilitation period may be more difficult to deal with than the actual surgery. In general, a rehabilitation period of six months to a year is required to regain pre-surgery strength and use. This is very dependent on the rehabilitation assignment provided by the surgeon as well as the person who is receiving the surgery. External bracing is recommended for athletes in contact and collision sports for a period of time after reconstruction. It is important however to realize that this type of prevention is given by a 'surgeon to surgeon' basis; all surgeons will prescribe a brace and crutches for post surgery recovery. Total usage time is one month. After surgery, no sports are allowed for 6 to 7 months. Whether the ACL deficient knee is reconstructed or not, the patient is susceptible to early onset of chronic degenerative joint disease
Osteoarthritis
Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...
.
Rehabilitation
The rehabilitation process is a very important part of the surgery. There is a long and rigorous process involved in getting back to one hundred percent. The doctor will start the patient on the rehabilitation program, which is broken down into phases:Phase 1:
This step is called the early rehabilitation phase. This is basically the things that were covered in short term, things to reduce pain and swelling while gaining movement.
Phase 2:
This phase covers weeks 3 and 4. At this point the pain should be subsiding and the patient will be ready to try more things that their knee isn’t willing to perform. That is why there is a lot of emphasis put on joint protection during this step. The patient will be able to start doing exercises such as mini wall sits and riding stationary bikes. The aim of this is to be able to bend the knee 100 degrees.
Phase 3:
This phase is known as the controlled ambulation phase and it covers weeks 4 to 6. At this point the patient will be doing the same exercises from phase 2 plus some more challenging ones. The patient will try to get their knee to bend 130 degrees during this stage. The aim during this period is to focus heavily on improving balance.
Phase 4:
This is the moderate protection phase and it covers weeks 6 to 8. In this period the patient will try to obtain full range of motion as well as increase resistance for the workouts.
Phase 5:
This is the light activity phase and it covers weeks 8 to 10. This period will place particular emphasis on strengthening exercises, with increased concentration on balance and mobility.
Phase 6:
This is the return to activity phase and it lasts from week 10 until the target activity level is reached. At this point the patient will be able to start jogging and performing moderately intense agility drills. Somewhere between month 3 and month 6 the surgeon will probably request that the patient perform physical tests so s/he can monitor the activity level. When the doctor feels comfortable with the progress of the patient, s/he will clear that person to resume a fully active lifestyle.
Epidemiology
Mountcastle et al. performed a study on gender difference in ACL tears in relationship with physical activities. The researchers performed an epidemiology study on young athletic populations. Previous studies found that women that participate in the same physical activities as men are more at risk for ACL injuries. The authors hypothesize that the frequency rate for males and females in the athletic and college aged population is the same. The study looked at college graduation classes from 1994-2003 at major institutions. The players who received a whole tear were examined for apparatus of injury and the type of sport they played when the injury occurred. The authors calculated the accident rate, opinion of danger, gender incidents, class year, and the accident rate differentiating men and women. There were 353 ACL injuries in 10 classes during the span of the study. The researchers calculated a 4-year accident proportion of 3.24 per 100 students for men, and 3.51 for women. Overall, the ACL injury rate not including male-only sports was substantially greater in women with an incidence ratio of 1.51 (pg 5). Women are more likely to get injured at gymnastics courses with an incidence ratio of 5.67; with an indoor obstacle course test the rate is 3.72; and there is a 2.42 incidence ratio on basketball. The authors concluded that there is slim gender difference in gender ACL tear. On the other hand, there were significant gender differences in ACL injury rates when particular specific sports and physical activities were compared.A notable finding is that women are three times more likely to have an ACL injury than men, due to variations of hormone levels and greater ligament strength in men than in women. Most importantly, there is substantial difference in neuromuscular coordination and control in landing—women have less hip and knee flexion. Women also have wider cue angles than men, and this combined with their weakened hip strength makes them more prone to an ACL tear. You especially see this with Women's Basketball and Volleyball. Athletic trainers and team physicians advise female athletes to adapt an ACL conditioning program.