Vascular supply to the acetabular labrum.

Background: The acetabular labrum plays an important role in hip joint stability and protection of the articular cartilage of the hip. Despite this, few investigators have evaluated its microscopic vasculature and, to our knowledge, none has assessed its macroscopic blood supply. The purposes of this study were to identify the origin and course of the vascular supply to the acetabular labrum to determine if this blood supply is affected by a labral tear.

Methods: Colored silicone was injected into the vascular tree proximal to thirty-five hips in twenty-eight fresh cadavers. Twenty-four hours after injection, anatomic dissection was performed and the vessels supplying the labrum were followed from their origin to their final distribution. Additionally, labral segments of fifteen randomly selected hips were resected to assess the acetabular rim's vascular contribution, and fifteen hips were dislocated for complete intra-articular inspection of the labrum.

Results: Radial branches of a previously described periacetabular periosteal vascular ring were identified as the source of labral blood supply in all thirty-five hips. These branches coursed toward the hip joint on the periosteal surface, penetrated the joint capsule near its innominate insertion, and continued within a loose connective-tissue layer on the capsular surface of the labrum. No contribution from the hip capsule, synovial lining, or osseous acetabular rim could be demonstrated. An intact vascular supply was identified in all seven hips with a labral tear.

Conclusions: The acetabular labrum receives its blood supply from radial branches of a periacetabular periosteal vascular ring that traverses the osseolabral junction on its capsular side and continues toward the labrum's free edge. The hip capsule, the synovial lining, and the osseous acetabular rim do not appear to provide substantial contributions to the labral blood supply.