User:Jessemetric/sandbox

=Role= The biomechanical role of the acetabular labrum is not fully understood. It is thought to help stabilize and decrease contact stress on the hip joint by increasing contact area and acting as a sealing mechanism for the synovial fluid in the joint. This allows some load to be carried by fluid pressurization. The labrum is primarily avascular and thus has poor ability to heal.

=Mechanism of Injury= It is estimated that 75% of acetabular labrum tears have an unknown cause. 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. A tight iliopsoas tendon has also been attributed to labrum tears by causing compression or traction injuries that eventually lead to a labrum tear. Most labrum tears are thought to be from gradual tear due to repetitive microtrauma. Incidents of labrum tears increase with age, suggesting that they may also be caused by deterioration through the aging process. Labrum tears in athletes can occur from a single event or recurring trauma. 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, hyperextention, hyperflexion, excessive external rotation. Sporting activities are likely causes, specifically those that require frequent lateral rotation or pivoting on a loaded femur as in hockey or ballet. 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. Tears of the hip labrum can be classified in a variety of ways, including morphology, etiology, location, or severity.