THA Patients in Standing and Sitting Positions: A Prospective Evaluation Using the Low-Dose “Full-Body” EOS® Imaging System

Variations in pelvic tilt according to the patient's posture may significantly modify the cup orientation and the prosthetic hip biomechanics. This study reports the “functional” positions of a 150 THA cohort using exclusively the novel EOS technology with a specific interest on the radiation dose delivered. The average dose for full-body acquisition was between 0.50 and 1.54 mGy. Globally, an 18° decrease of sacral slope is observed from the standing to the sitting position. A significant increase of cup frontal and sagittal inclination and anteversion were observed in the sitting position. The slot-scanning radiography provides direct numerical descriptors of the pelvic/hip functional relationships.