Color Doppler hemodynamic evaluation of flow to normal hip.

Abstract

This study was aimed to quantitate hemodynamic flow to the normal proximal femur and to evaluate the effect of internal rotation on blood flow measurements in the hip to assess the capability of Doppler ultrasonography to detect a simulated ischemic situation. Forty hips in 20 adult healthy volunteers age 22 to 62 years (mean age, 39.5 years) were examined in the supine position in neutral position and during internal rotation (simulated ischemia). Medial and lateral circumflex arteries and veins were examined using standard ultrasound equipment with color and power Doppler capabilities. Arterial pulsatility index and maximal arterial and venous velocities were determined. Pulsatility index values in the medial circumflex artery were significantly (P < 0.05) changed during internal rotation of the leg. A drop in pulsatility index of more than 1.4 on the right and 2.2 on the left hip with respect to the normal neutral position was considered abnormal. The peak systolic velocity did not change significantly. The venous return showed a consistent increase in flow velocity during internal rotation, but this was borderline in terms of significance. Participants older than 40 years showed more prominent changes in pulsatility index during internal rotation. Repeat measurements performed in 10 hips showed only a 5% mean change in the pulsatility index values from the previous series of measurements. Changes in pulsatility index values occurred when flow in the proximal femur was compromised (internal rotation). These changes were particularly significant in the medial circumflex artery, which is the primary vascular supply of the femoral head and neck. Changes also were observed in the circumflex veins (velocity increased) on internal rotation; however, they were not statistically significant. Doppler ultrasonography of the medial circumflex artery is a potential tool for the assessment and follow-up of hip vascularity.