MRI Of The Hip For Labral Tears

We are one of the few MRI facilities properly equipped to produce detailed images prior to surgery. 

Introduction – Labral Tears Of The Hip

Labral (acetabular) tears cause stiffness, pain, and additional symptoms in the hip that can be disabling. If the labrum is damaged, frayed, or torn, this causes pain. Labral injuries most often occur to active adults between 20 and 40 years of age. The injury requires treatment for them to remain functional and active. Recent changes in the manner of treatment stems from ongoing studies. Now, a more conservative, non-operative approach is preferred than a surgical approach.

The following guide will help you understand:

– Which parts of the hip are involved
– Why the condition occurs
– How the condition is diagnosed
– Why a 3T MRI Arthrogram is needed
– Which treatment options are available

Anatomical Structure

Which parts of the hip are involved?

A fibrous rim of cartilage, known as the acetabular labrum, is located around the hip socket and aids in normal hip function. The acetabular labrum keeps the head of the thighbone (femur) within the hip socket (acetabulum) and keeps the joint stable.

Within the last 10 years, our understanding of the acetabular labrum has increased. With high-powered photography and better laboratory techniques, it has been possible to have a closer look at the hip and its structures.

The rim of the acetabulum is surrounded by a piece of connective tissue called the labrum. The labrum has two sides. One side of the labrum encounters the femoral head, while the other side touches and is interconnected with the joint capsule. Strong ligaments make up the joint capsule and these ligaments surround the hip to keep it in place, while facilitating movement in several directions.

An important discovery lead to finding out there are two distinct zones of the labrum. The side next to the joint capsule, the extra-articular side, is blood-rich. However, the side next to the joint, the intra-articular zone, is avascular, meaning it is lacks a blood supply. Any damage that occurs to the extra-articular zone has a better chance of healing, due to the blood supply, than the intra-articular zone. After a surgical repair or injury, the intra-articular zone typically does not heal well, due to its lack of blood supply.

The labrum also functions to help seal the joint and maintain fluid pressure within the joint. This provides the entire joint with adequate nutrition. Without the seal, there is an increased risk of premature degenerative arthritis. Damage to the labrum can also cause a change in the hip’s center of rotation. This change increases the load and impact on the joint. When the seal cannot provide protection or the hip becomes off-center, repetitive motion and stress causes numerous small injuries to the hip joint and labrum. Eventually, these small injuries cause wear and tear on the hip joint.

Causes

Why does this condition occur?

Previously, it was believed labral tears occurred due to a single injury, such as from running, slipping, or twisting. With better radiographic imaging techniques and anatomy studies, it is clearer that abnormalities in the shape and structure of the acetabulum, femoral head, and/or labrum, can also contribute to problems.

Most labral tears are caused by injuries. However, labral tears caused by anatomical changes when combined with repetitive stress injuries can cause a gradual onset of problems. Any athletic activities requiring repeated hip flexion or pivoting motions can cause several small injuries.

What are the anatomical changes? The most common anatomical change is femoral acetabular impingement (FAI), which is the major cause of labral tears in the hip. In FAI, the joint clearance between the femoral head and neck within the acetabular rim is decreased.

As the leg bends, rotates internally, and moves toward the body, the femoral neck bone butts up against the acetabular rim and causes the labrum to become pinched between the femoral neck and acetabular rim. Eventually, the pinching (impingement) of the labrum will cause it to fray and tear along the edges. If the labrum is ruptured, this is called an avulsion, and the labrum becomes separated from where it normally attaches at the edge of the acetabulum.

The deviations of normal hip function combined with the weakness of muscles around the hip can cause acetabular labrum tears. Other causes can include loose ligaments (laxity) in the joint capsule, traction problems, degenerative arthritis changes associated with aging, or a shallow hip socket (hip dysplasia). Childhood hip diseases, such as Legg-Calve-Perthes disease, slipped capital femoral epiphysis, or hip dysplasia, can also increase the risk for labral tears.

Symptoms

What symptoms are associated with the condition?

Pain located in the front of the hip or groin area is the most common symptom associated with acetabular labral tears of the hip. The pain is usually accompanied by catching of the joint, locking, or clicking. Another common symptom is joint stiffness and a feeling of instability. The hip and leg may feel like it will buckle. Pain can also travel (radiate) toward the knee, along the side of the hip, or toward the buttocks.

The pain and other symptoms are often worse after walking, standing, or sitting for long periods. A pivoting motion on the affected leg causes pain. Patients with an acetabular labral tear will often limp while walking and have a positive Trendelenburg sign. A positive Trendelenburg sign occurs when the hip drops down on the right side when standing on the left leg and vice versa. Pain associated with the tear is often constant and can cause patients to limit their sports participation and recreational activities.

Diagnosis

How is the condition diagnosed?

Hip labral tears are initially diagnosed based on medical history and physical examination. A history of trauma linked to the hip pain may or may not be present. If there are structural, anatomical, or muscle imbalances, which contribute to the labral tear, the symptoms can develop gradually.

Several tests will be used to help your doctor make a diagnosis. A common test is an impingement sign. During the test, the hip is bent at 90 degrees of flexion and rotated internally. Then the thigh is brought toward the other hip.

Making a diagnosis is not always easy. The condition is frequently misdiagnosed because there are many underlying causes of hip pain. Pain caused by labral tears can be difficult to pinpoint. Your doctor needs additional tests to help locate the cause of pain. Some tests may include injecting lidocaine, a local anesthetic, into the joint to determine if the pain is coming from inside or outside of the joint.

X-rays are also useful to have a picture of abnormalities of the entire hip structure and location of the hip’s position. Magnetic resonance imaging (MRI) is used to see abnormalities of the soft tissues of the hip, such as muscles, tendons, labrum, cartilage, etc. 3T MRIs are offer the best non-surgical view of the joint and can give the doctor critical insight into the problem and treatment plan.

Another test called the magnetic resonance arthrography (MRA) is now used to make a diagnosis, and is considered the gold standard. Studies have shown MRA has a high sensitivity and specificity for labral tears. Although arthroscopic examination is 100 percent accurate, it is more invasive because it requires a surgical procedure.

For an MRA, gadolinium (a contrast dye) is injected into the hip joint and irregularities in the joint surface can be seen as the dye seeps into these areas. MRA gives surgeons the ability to view the location and extent of labral tears, in addition to bone abnormalities that need to be repaired during the surgery.

Treatment Options

What types of treatments are available?

Formerly, the only way to confirm that a labral tear existed was to perform arthroscopic surgery. If a tear was discovered during the arthroscopic examination, then the surgeon immediately did the repair. However, this approach to the problem was questioned by several studies conducted over the years. It was found that when the labrum was removed, the hip functioned differently, friction increased on the joint, and the increased load the hip now had to bear led to increased instances of osteoarthritis and other degenerative changes.

Instead of removing the damaged labrum, they began repairing it. In addition, studies by physical therapists indicated that resolving issues of muscle imbalances and strengthening muscles reduced the need for surgical repair and the risks associated with surgery could be avoided.

Currently, labral tears are being managed with nonoperative (conservative) care. This type of treatment is possible when there are no signs of labral pathology. Others who benefit from conservative care include patients with only minor alterations in the structure and shape of their hip or who have normal hip anatomy and in whom labral tears that have been confirmed.

Nonsurgical Treatment Methods

Physical therapy is often recommended. Prior to starting the therapy, a joint motion examination is conducted that includes an analysis of movement or gait, body alignment, overall posture, and the muscle strength of the knee, trunk, and hip. Based on the individual characteristics and factors discovered, each patient receives an individually designed plan of care.

Activity modification is the start of nonoperative care. Patients are advised to avoid weight-bearing activities for prolonged periods of time and not to pivot on the affected leg. During physical therapy, you will work to improve your posture, restore normal neuromuscular control, and strengthen the muscles of your hip. Each of these will reduce your pain and improve the functionality of your hip.

In certain positions, taut muscles surrounding the hip will cause pinching between the acetabulum and the femoral head. Any bony abnormalities will not be changed by a program of stretching exercises designed to increase flexibility, but these exercises will help to reduce contact and impingement in the future by lengthening the muscles.

In order to pull the hip into external rotation, a thin elastic SERF (Stability through External Rotation of the Femur) strap is applied around the lower leg, knee and thigh. The strap is designed to improve leg movement and hip control during times of activity. At the same time, it is also vital that the muscles be strengthened to avoid the possibility of long term dependence on external support.

Intra-articular injections of cortisone are sometimes beneficial. As an anti-inflammatory medication, cortisone is very potent. Pain symptoms for several weeks or even months are reduced after an injection.

Surgical Methods

To repair the torn labrum, arthroscopic surgery is often performed. In order to see and operate within a joint, a small fiber optic tube known as the arthroscope is used. On the outer end of the arthroscope lens, a TV camera is attached. The surgeon sees a projected image of the hip joint interior on a screen nearby. As the surgeon moves the arthroscope to different places inside the hip, he or she does not look at the hip, but focuses on the television screen.

The torn tissue surrounding the rim of the acetabula is trimmed and followed by the reattachment of the damaged labrum to the acetebular rim bone during the labral refixation procedure. Individual layers of tissue are surgically sewn together and reattached as closely as possible to their original position along the rim of the acetabula.

Debridement of the torn labral tissue is often done when repair isn’t a possibility. When tissue is debrided, it means that weakened, torn, or damaged parts of it are removed. The removal of these damaged fragments prevents them from causing further damage and additional pain in the hip joint.

A correction of bone abnormalities or open treatment of femoroacetabular impingement may be required in some cases. These procedures often require a prolonged stay in the hospital because they are quite involved.

Rehabilitation Choices

After treatment, what can I expect?

Rehabilitation Without Surgery

Conservative management goals include the relief of pain and improvements in functionality through the correction of imbalances in muscle strength. As long as there is no pain during activities or motion, it is possible to return to a full level of activities when both legs are equally strong.

Sports and other recreational activities as well as normal daily living are included in this plan for active, young adults. In the case of older adults who have degenerative arthritis, the expectation is that most normal daily activities will be resumed, but that prolonged standing or sitting positions must be limited.

Rehabilitation After Surgery

Pain relief and improved function happens when a labral tear is corrected. Long term studies have not yet been performed to prove that early treatment can prevent changes due to arthritis but there is hoped that this is true.

Expect recovery to last four to six months after having surgery to repair hip labral tears. To sum up, six months after surgery has been performed, normal activities can be resumed. This time frame seems to be too long for highly active adults, and athletes in particular.

However, recovery is much faster when people follow the recommended exercise progression in the rehab plan of care. When all of the exercises can be performed without pain or other symptoms and in good form, discharge from rehab takes place. If hip and/or groin pain reoccurs, it should be immediately reported to the orthopedic surgeon.