Capsular and Pericapsular Contributions to Acetabular and Femoral Head Perfusion

Background: Capsular and pericapsular vessels are believed to contribute to acetabular and femoral head perfusion, but, to our knowledge, there is no anatomic study to support this theory. The purpose of this study was to describe the vascular anatomy of the hip with particular reference to the contributions of the capsular and pericapsular vessels. Methods: Twenty fresh cadavers were dissected twenty-four hours after intra-arterial injection of colored silicone. The arteries supplying the hip were followed by careful dissection from their origins outside the pelvis to their terminal branches. Particular attention was paid to the vessels traveling between the acetabulum and the capsule and the femoral head. Results: In all twenty specimens, the hip capsule received blood supply from the superior and inferior gluteal arteries proximally and from the medial and lateral femoral circumflex arteries distally. The contributory vessels entered the capsule peripherally and superficially. The circumflex arteries supplied the anterior capsule. The gluteal arteries supplied the posterior and posterosuperior aspect of the hip capsule, augmented by contributions from the circumflex arteries. Variable anastomoses were found between the gluteal and femoral systems on the capsular surface beneath the gluteus minimus and short hip external rotators. The medial femoral circumflex artery provided the dominant blood supply to the femoral head in eighteen specimens, and the inferior gluteal artery provided the dominant supply in two specimens. Conclusions: Capsular and pericapsular vessels that contribute to the blood supply of the acetabulum run on the posterior and posterolateral surface of the capsule. The dominant blood supply to the femoral head comes from vessels that approach the joint posteriorly and penetrate the joint near the femoral attachment of the capsule. Clinical Relevance: Surgical approaches to the hip that separate the gluteus minimus and short hip external rotators from the capsule may interfere with the blood supply of the acetabulum and femoral head. Certain arthroscopic approaches may also place these vascular structures at risk.