Which vessel is most at risk for avascular necrosis after an intracapsular femoral neck fracture?

Which vessel is most at risk for avascular necrosis after an intracapsular femoral neck fracture?

• A. Lateral femoral circumflex artery
• B. Inferior gluteal artery
• C. Medial femoral circumflex artery
• D. Obturator artery

Answer: (C)

The femoral head relies on the medial femoral circumflex artery, whose retinacular branches run up along the femoral neck beneath the joint capsule to nourish the head. An intracapsular fracture typically disrupts these retinacular vessels, cutting off the head’s main blood supply and greatly increasing the risk of avascular necrosis. The artery of the ligamentum teres (from the obturator) contributes only a minor amount of perfusion, so its preservation wouldn’t prevent AVN if the medial femoral circumflex vessels are torn. The inferior gluteal and lateral femoral circumflex arteries are not the primary sources for the femoral head, so they’re less implicated in AVN after this fracture. Therefore, the medial femoral circumflex artery is the vessel most at risk.

The femoral head relies on the medial femoral circumflex artery, whose retinacular branches run up along the femoral neck beneath the joint capsule to nourish the head. An intracapsular fracture typically disrupts these retinacular vessels, cutting off the head’s main blood supply and greatly increasing the risk of avascular necrosis. The artery of the ligamentum teres (from the obturator) contributes only a minor amount of perfusion, so its preservation wouldn’t prevent AVN if the medial femoral circumflex vessels are torn. The inferior gluteal and lateral femoral circumflex arteries are not the primary sources for the femoral head, so they’re less implicated in AVN after this fracture. Therefore, the medial femoral circumflex artery is the vessel most at risk.