Acetabular labrum | |
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Details | |
Identifiers | |
Latin | labrum acetabuli |
TA98 | A03.6.07.008 |
TA2 | 1880 |
FMA | 43521 |
Anatomical terminology |
The acetabular labrum (glenoidal labrum of the hip joint or cotyloid ligament in older texts) is a fibrocartilaginous ring [1] [2] [3] which surrounds the circumference of the acetabulum of the hip, deepening the acetabulum. The labrum is attached onto the bony rim and transverse acetabular ligament. It is triangular in cross-section (with the apex represented by the free margin). [2] [3]
The labrum contributes to the articular surface of the joint [2] [1] (increasing it by almost 10% [1] ). It embraces the femoral head, [2] holding it firmly in the joint socket [3] to stabilise the joint. It thus also seals the joint cavity, facilitating even distribution of synovial fluid so that friction is reduced and dissolved nutrients are better distributed. [2]
The anterior portion of the labrum is most susceptible to tears.
It has been suggested that this section be split out into another articletitled Acetabular labrum tear . (Discuss) (August 2023) |
It is estimated that 75% of acetabular labrum tears have an unknown cause. [4] Tears of the labrum have been credited to a variety of causes such as excessive force, hip dislocation, capsular hip hypermobility, hip dysplasia, and hip degeneration. [4] A tight iliopsoas tendon has also been attributed to labrum tears by causing compression or traction injuries that eventually lead to a labrum tear. [5] Most labrum tears are thought to be from gradual tear due to repetitive microtrauma. [4] Incidents of labrum tears increase with age, suggesting that they may also be caused by deterioration through the aging process. [4] Labrum tears in athletes can occur from a single event or recurring trauma. [6] Running can cause labrum tears due to the labrum being used more for weight bearing and taking excessive forces while at the end-range motion of the leg: hyperabduction, hyperextension, hyperflexion, excessive external rotation. [6] Sporting activities are likely causes, specifically those that require frequent lateral rotation or pivoting on a loaded femur as in hockey or ballet. [4] Constant hip rotation places increased stress on the capsular tissue and damage to the iliofemoral ligament. This in turn causes hip rotational instability putting increased pressure on the labrum. [6]
Traumatic injuries are most commonly seen in athletes who participate in contact or high impact sports like football, soccer, or golf. [7] The prevalence rate for traumatic hip injuries that causes a tear of the labrum is very low. Less than 25% of all patients can relate a specific incident to their torn labrum; however, they are often a result of a dislocation or fracture. [8] Falling on one's side causes a blunt trauma to the greater trochanter of the femur. Since there is very little soft tissue to diminish the force between the impact and the greater trochanter, the entire blow is transferred to the surface of the hip joint. [9] And since bone density does not reach its peak until the age of 30, hip traumas could result in a fracture. [9] Tears of the hip labrum can be classified in a variety of ways, including morphology, etiology, location, or severity. [7]
Anatomical modifications of the femur and or hip socket cause a slow buildup of damage to the cartilage. Femur or acetabular dysplasia can lead to femoral acetabular impingement (FAI). [10] Impingement occurs when the femoral head rubs abnormally or lacks a full range of motion in the acetabular socket. [10] There are three different forms of FAI. The first form is caused by a cam-deformity where extra bone is present on the femoral head, which leads to the head being non-spherical. [7] The second deformity is referred to as a pincer deformity and it is due to an excess growth of the acetabular socket. [7] The third type of FAI is a combination of the first two deformities. When either abnormality is present, it changes the position that the femoral head occupies in the hip socket. The increased stresses that the femur and or acetabulum experience may lead to a fracture of the acetabular rim or a detachment of the overstressed labrum. [7]
A acetabular labrum tear is assessed by physical examination followed by medical imaging. An MR arthrogram is more reliable than magnetic resonance imaging. A full confirmation can be done by arthroscopy. [11] [12] [13]
In the United States acetabular labrum tears usually occur in the anterior or anterior-superior area, possibly due to a sudden change from labrum to acetabular cartilage. [5] The most common labrum tears in Japan are in the posterior region, likely due to the customary practice of sitting on the floor. [7] Posterior labrum tears in the Western world usually occur when a force drives the femoral head posteriorly which transfers shear and compressive forces to the posterior labrum. [7]
With physical therapy, there is only a small amount of evidence on rehabilitation techniques for the acetabular labrum. [14] It is even thought that physical therapy could be controversial due to there not being any evidence of a specific effective therapy routine. [7] There are, however, some studies that report physical therapy could benefit the patient by bringing them back to “sports-ready” capabilities. [4] It is advised that physical therapists keep up on the new findings and stay in close contact with the orthopaedic surgeon so they have the best idea of how to approach their patient's case. [14] Following surgery, crutches will be used for up to six weeks and there should be no expectation to return to activities such as running for at least a period of six months. [15]
Some things to note when rehabilitation occurs is that it is important to know the size and placement of the tear. There are usually four phases in the rehabilitation process noted as: "Phase I: initial exercises (weeks 1–4), Phase II: intermediate exercises (weeks 5–7), Phase III: advanced exercises (weeks 8–12), and Phase IV: return to sports (weeks 12+)". [14] All physical therapy regimens should be individualized from person to person based on all adequate criteria [16]
In phase I of the rehabilitation process the first objective is to minimize the pain and inflammation. It is important to begin conducting small motion exercises that have up to 50% weight bearing capacity by the patient. A symmetrical gait pattern is imperative as not to create an imbalance in the muscles of the hip. Aquatic therapy is highly encouraged and looked upon due to its ability to help the patient move more freely without the pressure of gravity. To progress to phase II of the rehabilitation process patients should be able to complete straight leg raises while lying on their side to strengthen the sartorius and tensor fasciate latae muscles to build support in the leg.
In phase II the physical therapist should be trying to promote more flexibility in the soft tissue. There should be more emphasis on the beginning aspects of strength training while adding some resistance over time. In order to progress to phase III, the patient should be able to demonstrate a normal gait pattern and minimal pain with exercises like the single leg bridging to help strengthen the hamstring muscles to help with leg equality.
In phase III the focus is to begin building functional strength. Movements should include single leg exercises to build the muscle and challenge the strength of the hip.
In order to progress to phase IV the flexibility of the patient should be adequate. Phase IV is the final stage in which the physical therapist would assess and prescribe any further exercise up until the patient is ready to return to the sport. [14] Usually the therapist would start using complex movements like squatting, kicking, and running. The therapist would look for symmetrical movements on both sides of the body without pain. If the patient demonstrates the symmetrical movements without pain, the physical therapist would use their discretion for the patient's clearance. Some things to avoid from while rehabilitating are sitting with "knees lower than the hips, legs crossed where hip is rotated, and sitting on the edge of the seat and contracting the hip flexor muscles." [4]
Hip labrum tear can occur in a variety of ways such as frequent twisting movement, direct trauma, or degeneration. [4] Despite the many different possibilities, a large percentage of hip labral tears are not directly related to any specific action, [7] making it difficult to prevent such an injury. But it may be possible to lower the risk by strengthening the gluteus, stretching before exercise, and discontinued use of repetitive twisting activities.
One way to prevent a hip labrum tear is to decrease the pressure on the anterior region. The labrum is about 2 to 3 mm thick but is wider and thinner in the anterior portion. [4] Studies have found that in the United States and European countries, hip labral tears are commonly found in the anterior region. [4] Muscular imbalance of the pelvis can develop lower crossed syndrome. It is caused by tight hip flexors and erector spinae with inhibited weak gluteals and abdominals. [14] Imbalance of the muscles can lead to an anterior pelvic tilt, increased hip flexion, and lumbar hyperlordosis of the lumbar spine. This increases the pressure in the anterior labrum. [7] Weak gluteals during hip extension has also shown increased joint pressure in the anterior labrum. [17] To prevent a hip labrum tear, you will have to strengthen muscles or stretch tight muscles that might cause any muscular imbalance. A great exercise to strengthen the gluteus is the side lying hip abduction. You will be lying on your side with your legs on top of each other. You will raise the top leg up while keeping the knee and hip straight. This exercise targets the gluteus medius and is effective especially in those with an anterior pelvic tilt. [14] To stretch a tight hip flexor, you can do the kneeling hip flexor stretch that targets the iliopsoas. These exercises are a great way to strengthen and stabilize the pelvis and hip joint to prevent a hip labrum tear.
Stretching before exercise will affect the cartilage through "creep". It will place a constant load on the labrum, allowing fluid the leak out and deform to the applied load. This is significant for the viscoelasticity of the labrum. [18] The hip labrum acts as a shock absorber, joint lubricator, stabilizer and pressure distributor. [4] With this essential warm up, it is possible for it to be better prepared to prevent a hip labrum tear. Body weight squats are a great example of stretching and warming up the body to induce creep before exercise.
The human leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.
The posterior cruciate ligament (PCL) is a ligament in each knee of humans and various other animals. It works as a counterpart to the anterior cruciate ligament (ACL). It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.
The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments in the human knee. The two ligaments are also called "cruciform" ligaments, as they are arranged in a crossed formation. In the quadruped stifle joint, based on its anatomical position, it is also referred to as the cranial cruciate ligament. The term cruciate translates to cross. This name is fitting because the ACL crosses the posterior cruciate ligament to form an “X”. It is composed of strong, fibrous material and assists in controlling excessive motion. This is done by limiting mobility of the joint. The anterior cruciate ligament is one of the four main ligaments of the knee, providing 85% of the restraining force to anterior tibial displacement at 30 and 90° of knee flexion. The ACL is the most injured ligament of the four located in the knee.
The piriformis muscle is a flat, pyramidally-shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group.
In vertebrate anatomy, hip refers to either an anatomical region or a joint.
Anterior cruciate ligament reconstruction is a surgical tissue graft replacement of the anterior cruciate ligament, located in the knee, to restore its function after an injury. The torn ligament can either be removed from the knee, or preserved before reconstruction through an arthroscopic procedure. ACL repair is also a surgical option. This involves repairing the ACL by re-attaching it, instead of performing a reconstruction. Theoretical advantages of repair include faster recovery and a lack of donor site morbidity, but randomised controlled trials and long-term data regarding re-rupture rates using contemporary surgical techniques are lacking.
The psoas major is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the iliopsoas. In animals, this muscle is equivalent to the tenderloin.
The iliacus is a flat, triangular muscle which fills the iliac fossa. It forms the lateral portion of iliopsoas, providing flexion of the thigh and lower limb at the acetabulofemoral joint.
The iliopsoas muscle refers to the joined psoas major and the iliacus muscles. The two muscles are separate in the abdomen, but usually merge in the thigh. They are usually given the common name iliopsoas. The iliopsoas muscle joins to the femur at the lesser trochanter. It acts as the strongest flexor of the hip.
A hip dislocation is when the thighbone (femur) separates from the hip bone (pelvis). Specifically it is when the ball–shaped head of the femur separates from its cup–shaped socket in the hip bone, known as the acetabulum. The joint of the femur and pelvis is very stable, secured by both bony and soft-tissue constraints. With that, dislocation would require significant force which typically results from significant trauma such as from a motor vehicle collision or from a fall from elevation. Hip dislocations can also occur following a hip replacement or from a developmental abnormality known as hip dysplasia.
Snapping hip syndrome, also referred to as dancer's hip, is a medical condition characterized by a snapping sensation felt when the hip is flexed and extended. This may be accompanied by a snapping or popping noise and pain or discomfort. Pain often decreases with rest and diminished activity. Snapping hip syndrome is commonly classified by the location of the snapping as either extra-articular or intra-articular.
A SLAP tear or SLAP lesion is an injury to the glenoid labrum. SLAP is an acronym for "superior labral tear from anterior to posterior".
A tear of a meniscus is a rupturing of one or more of the fibrocartilage strips in the knee called menisci. When doctors and patients refer to "torn cartilage" in the knee, they actually may be referring to an injury to a meniscus at the top of one of the tibiae. Menisci can be torn during innocuous activities such as walking or squatting. They can also be torn by traumatic force encountered in sports or other forms of physical exertion. The traumatic action is most often a twisting movement at the knee while the leg is bent. In older adults, the meniscus can be damaged following prolonged 'wear and tear'. Especially acute injuries can lead to displaced tears which can cause mechanical symptoms such as clicking, catching, or locking during motion of the joint. The joint will be in pain when in use, but when there is no load, the pain goes away.
Femoroacetabular impingement (FAI) is a condition involving one or more anatomical abnormalities of the hip joint, which is a ball and socket joint. It is a common cause of hip pain and discomfort in young and middle-aged adults. It occurs when the ball shaped femoral head contacts the acetabulum abnormally or does not permit a normal range of motion in the acetabular socket. Damage can occur to the articular cartilage, or labral cartilage, or both. The condition may be symptomatic or asymptomatic. It may cause osteoarthritis of the hip. Treatment options range from conservative management to surgery.
Pes anserine bursitis is an inflammatory condition of the medial (inner) knee at the anserine bursa, a sub muscular bursa, just below the pes anserinus.
Hip arthroscopy refers to the viewing of the interior of the acetabulofemoral (hip) joint through an arthroscope and the treatment of hip pathology through a minimally invasive approach. This technique is sometimes used to help in the treatment of various joint disorders and has gained popularity because of the small incisions used and shorter recovery times when compared with conventional surgical techniques. Hip arthroscopy was not feasible until recently, new technology in both the tools used and the ability to distract the hip joint has led to a recent surge in the ability to do hip arthroscopy and the popularity of it.
Pain in the hip is the experience of pain in the muscles or joints in the hip/ pelvic region, a condition commonly arising from any of a number of factors. Sometimes it is closely associated with lower back pain.
Labral reconstruction is a type of hip arthroscopy in which the patient's native labrum is partially or completely removed and reconstructed using either autograft or allograft tissue. Originally described in 2009 using the ligamentum teres capitis, arthroscopic labral reconstruction using a variety of graft tissue has demonstrated promising short and mid-term clinical outcomes. Most importantly, labral reconstruction has demonstrated utility when the patient's native labral tissue is far too damaged for debridement or repair.
Femoral nerve dysfunction, also known as femoral neuropathy, is a rare type of peripheral nervous system disorder that arises from damage to nerves, specifically the femoral nerve. Given the location of the femoral nerve, indications of dysfunction are centered around the lack of mobility and sensation in lower parts of the legs. The causes of such neuropathy can stem from both direct and indirect injuries, pressures and diseases. Physical examinations are usually first carried out, depending on the high severity of the injury. In the cases of patients with hemorrhage, imaging techniques are used before any physical examination. Another diagnostic method, electrodiagnostic studies, are recognized as the gold standard that is used to confirm the injury of the femoral nerve. After diagnosis, different treatment methods are provided to the patients depending upon their symptoms in order to effectively target the underlying causes. Currently, femoral neuropathy is highly underdiagnosed and its precedent medical history is not well documented worldwide.
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