Vascularity of the neonatal femoral head: In vivo demonstration with power Doppler US

PURPOSE: To detect the intrinsic blood supply of the unossified neonatal femoral head in vivo by using power Doppler ultrasound (US) and to ascertain whether a reduction in blood flow could be demonstrated with hip abduction. MATERIALS AND METHODS: One hip of 13 neonates was examined with power Doppler sonography. After vessels within the femoral head were identified, the thigh was slowly abducted and the angle at which now became undetectable was recorded. Spectral Doppler tracings were obtained in all subjects. RESULTS: Intrinsic blood flow of the femoral head was demonstrated in all subjects. Flow became undetectable during hip abduction in 11 of 13 neonates and reappeared during adduction. The angle at which now became undetectable varied from 60 degrees to 85 degrees. Spectral Doppler signals demonstrated a mixed arterial and venous trace. CONCLUSION: Power Doppler US provides a simple real-time assessment of the femoral head blood supply. This may prove helpful in identifying neonates at risk of avascular necrosis, a complication of treatment of hip dysplasia with abduction hip restraints.