Acetabular Labral Tear - Causes, Symptoms and Treatment

Introduction

The hip joint is one of the ball and socket joints. The ball portion of the joint is the head of the femur bone (thigh bone), and the socket portion is the acetabulum. It is formed by the three bones of the hip; the ileum, the pubis, and the ischium bones. The acetabulum is located inferior and laterally to the pelvis and forms a cup-like structure to support the head of the femur bone, together forming the hip joint. The cartilage (labrum) is a band of soft connective tissue that is smooth and slippery; it lines the rim of the socket and protects and cushions the joint of the hip bones, distributing the pressure equally while maintaining alignment during motion. The presence of tissue fluid helps achieve stability and frictionless joint movement.

What Is Acetabular Labral Tear?

An injury or damage to the cartilage and the tissues of the hip socket is called an acetabular labral tear. It is commonly seen in females and individuals with structural deformities. The acetabular labrum is a fibrocartilage; it is C-shaped, thick posterosuperior, and wide anterosuperiorly. It has three distinct layers; the external surface reinforced by the cartilaginous filaments; the middle layer, densely collagenous; and the articular surface, oriented with chondrocytes (cartilage cells). The hip joint capsule is attached to the margins or adjacent to the acetabulum and transverse ligaments.

What Are the Types of Acetabular Tears?

Acetabular labral tears are of two types; anterior labral tears and posterior labral tears. Anterior tears are more consistent and occur in the anterior hip region or groin. Posterior labral tears occur in the lateral or the deep posterior region or buttocks. The extent of the labral tears usually varies among individuals, depending on the cause of injury. It may be partial tears or fray at the edges, mainly due to gradual wear (degeneration), or it may be a separation of a section or a complete tear following a trauma (detachment).

What Are the Causes of Acetabular Labral Tears?

Some of the causes of acetabular labral tears include:

• A direct Injury to the hip joint due to slipping, vehicle accidents, and sports injuries that may occur due to repetitive rotations, twisting, and high-impact movements, especially during football, golf, ice hockey, etc.

• Structural deformities like femoroacetabular impingement (FAI). It is an abnormal shape of the hip joint, wherein the femoral head does not fit properly in the socket (acetabulum) and results in pain and limited motion. If left untreated, it can lead to degeneration of the joint (osteoarthritis).

• Health conditions like osteoarthritis, that result in wear and tear, especially due to being overweight or old age.

What Are the Signs and Symptoms of Acetabular Labral Tears?

Some signs and symptoms of acetabular labral tears include:

• Pain and stiffness around the hip.

• A clicking or a locking sound on movement.

• Pain in the groin or buttocks region increases during long periods of sitting, standing, or physical activity.

• Difficulty bending or rotating the hip and unsteady walking.

What Are the Risk Factors Associated With Acetabular Labral Tears?

• Acetabular dysplasia (hip dysplasia) is a developmental disorder characterized by a shallow hip socket with an inadequate covering of the femoral head.

• Well-defined, multilocular cysts due to hip dysplasia or trauma called paralabral cysts may be associated with labral tears.

• Hyperlaxity and hypermobility of the joint capsule due to degeneration.

• A structural deformity is called femoroacetabular impingement, wherein the femoral head does not fit into the hip socket or the acetabulum.

• Osteoarthritis (joint inflammation mainly due to wear and tear of cartilage) may lead to degeneration and damage to the hip joint.

How Is Acetabular Labral Tear Diagnosed?

The doctor takes a thorough medical history, followed by a complete physical examination to check for lacerations, injuries, or swelling. The patient is asked to perform various movements like bending, walking, lifting the leg, and sitting and standing positions to assess the range of motion. Anesthetic injections are given in the joint space to diagnose the origin of the pain. If it relieves pain, it confirms a problem in the hip joint; if the pain persists, it originates outside the joint. Radiological investigations include:

• X-rays: It is recommended to view the shape and alignment of the hip joint and to rule out other hip joint pathologies. It is also advised in cases of osteoarthritis, acetabular cysts, and structural deformities of the hip, like hip dysplasia, femoroacetabular impingement, etc.

• Magnetic Resonance Imaging (MRI Scan): It is the most preferred diagnostic scan, as it provides a detailed view of the soft tissues around the joint. It helps to determine the location, extent, and severity of the injury. It is also advised to determine the integrity of the labrum in cases of joint effusion, para labral cysts, stripping of the joint capsule, etc.

• Magnetic Resonance Arthrography (MRA): It is used with an MRI scan, wherein a contrast material is injected into the joint space, providing a clear view of the labral tear.

How Is Acetabular Labral Tear Managed?

The initial treatment for patients with groin pain includes the provision of rest, with or without activity, depending on the severity, and medications such as non-steroidal anti-inflammatory drugs and intra-articular injections like corticosteroids are prescribed to relieve pain and inflammation. Physical therapy is often necessitated, as the pain recurs in most patients when they return to normal activities. The main aim of physical therapy is to improve the strength and control of the muscles around the hip joint. It is advised for recovery, especially in sports persons and athletes, in three phases, as given below:

• Phase I: The use of supportive devices in those experiencing severe pain, especially with weight bearing. Electrical stimulation, as well as laser therapy, is used to reduce pain. Light exercises are suggested, like crouching and bridging with knees and hands close to the floor.

• Phase II: Core muscle strengthening exercises in the form of mini squats, and lateral bridge exercises, that stabilize the pelvic floor muscles. Motor Sense training is advised by jumping board and balance board, and the normal range of motion is recovered.

• Phase III: Continuation of the same exercises more vigorously to achieve a good balance and restore normal muscle strength and range of motion.

Surgical management is recommended in cases of severe labral tears and recurrence of symptoms despite nonsurgical treatment.

• In case of simple tears, bioabsorbable suture anchors are placed over the torn labrum to stabilize the tissue back into the rim of the acetabular socket.

• Arthroscopic surgery is performed wherein small incisions are made around the labrum, and an arthroscope is inserted; it is a small device with a camera that shows the location of the tear, and with the insertion of surgical tools through the other incision, debridement of the frayed tissues is done. Irrigation is done, and the area is sutured. The main goal is to preserve as much labral tissue as possible, restore the suction seal, and stabilize the hip joint.

• Labral reconstruction is performed in cases of severe labral tears which cannot be corrected by surgical repair. Reconstruction is done under arthroscopy or by open surgery, and the damaged labrum is removed and replaced by an autograft (tissue taken from other parts of the body) or an allograft (tissue from a donor), followed by the closure of the surgical site with sutures, medications to relieve pain, and antibiotics to prevent infection.

Conclusion

An acetabular labral tear is an injury to the cartilage of the hip socket caused by accidents due to sports injuries or structural deformities of the hip. It is associated with hip and groin pain, stiffness, and limited range of motion. It is generally managed by conservative treatment, but severe labral tears require surgical treatment followed by medication therapy. Patients usually recover in a few months with proper care and evaluation.