METHOD FOR ALIGNING AN ACETABULAR CUP

摘要

An alignment system for aligning an acetabular cup insertion instrument utilizes pre-operative preferably standing x-rays and intra-operative x-rays to allow the surgeon to compensate for the position of a patient on an operating room table. The system uses a programmable computer connected to a digital x-ray system and an navigation tracking system to provide input for calculating the inclination and anteversion angles of an acetabular cup impactor based on a pre-operative plan developed from the standing x-rays. The system calculates changes in lengths and angles between anatomic landmarks on the pelvis to alter the intra-operative orientation of the acetabular reaming and impacting instruments to produce the desired inclination and anteversion angles when the pelvis is reoriented as the patient is placed on an operating table.

主权项

1. A method for aligning an acetabular cup insertion instrument comprising:
taking a pre-operative anterior/posterior view digital x-ray image and a lateral view pre-operative digital x-ray image of the pelvis of a patient; determining a desired acetabular cup abduction and anteversion, angle based on a pre-operative x-ray; identifying at least three points on the digital anterior/posterior digital x-ray image and at least two points on the lateral digital x-ray image; calculating the lengths and angles between each of the points on both the anterior/posterior pre-operative digital x-ray image and the lateral pre-operative digital x-ray image; positioning a patient on an operating table in an operating room, the operating table having a reference element thereon; taking at least one intra-operative pelvic digital x-ray image of the patient positioned on the operating table; identifying at least three points on the intra-operative x-ray image, the points corresponding to the points on the pre-operative x-ray image; calculating the lengths and angles between each of the at least three points on the intra-operative digital x-ray image; calculating an intra-operative angular deviation of the acetabular cup insertion instrument from the desired acetabular cup abduction and anteversion angle by comparing the dimensional differences between the points on the pre-operative x-ray images and the at least one intra-operative x-ray image; and intra-operatively aligning the acetabular cup insertion instrument to the calculated angular position, based on the intra-operative angular deviation from the desired abduction and anteversion angles, using angle measuring tools.