System and method for analyzing acetabular cup position

A computer system having one or more computers performing a method for preoperatively determining inclination and anteversion for an acetabular cup component of a hip implant in several anatomical positions to determine a risk of hip dislocation in the several anatomical positions, the method comprising:

• acquiring a plurality of two-dimensional preoperative images of a patient's pelvic region, the plurality of preoperative images including:
• an anteroposterior image of the patient's pelvic region in a first anatomical position;
• a lateral image of the patient's pelvic region in the first anatomical position;
• an image of the patient's pelvic region when the patient is in a second anatomical position;
• an image of the patient's pelvic region when the patient is in a third anatomical position;
• wherein the first, second, and third anatomical positions are distinct from each other and each is a seated, standing, or supine position;
• determining a sacral femoral pubic angle from the anteroposterior image of the patient's pelvic region in the first anatomical position;
• determining a spinal pelvic tilt angle from the lateral image of the patient's pelvic region in the first anatomical position;
• determining a patient specific sacral femoral pubic constant by adding the sacral femoral pubic angle from the anteroposterior image of the patient's pelvic region in the first anatomical position to the spinal pelvic tilt angle from the lateral image of the patient's pelvic region in the first anatomical position;
• determining a spinal pelvic tilt angle from the image of the patient's pelvic region in the second anatomical position;
• determining a pelvic tilt angle from the image of the patient's pelvic region when the third anatomical position;
• whereby the calculated pelvic tilt angles in the seated position, standing position, and supine position allow a surgeon to determine how the inclination and anteversion for the acetabular cup component of the hip implant will vary in each of the seated position, standing position, and supine position.