# US 10,500,067 B2 · Method for aligning an acetabular cup

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- Number: US 10,500,067 B2
- Document ID: US10500067B2
- Status: Granted
- Kind: B2
- Application number: 15/477,476
- Filed: 2017-04-03
- Published: 2017-07-20
- Granted: 2019-12-10
- Earliest claimed: 2013-09-26
- Assignees: Howmedica Osteonics Corp.
- Applicants: Howmedica Osteonics Corp.
- Inventors: Thomas Francis McCarthy
- Web page: https://patentgrep.com/patent/US10500067B2

## CPC

- A61F 2/4609: {of acetabular cups}
- A61B 17/1666: {for the acetabulum}
- A61B 34/10: Computer-aided planning, simulation or modelling of surgical operations
- A61B 34/20: Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
- A61B 17/1746: {for the acetabulum}
- A61B 2034/101: {Computer-aided simulation of surgical operations}
- A61B 2034/2055: {Optical tracking systems}
- A61B 2034/2065: {Tracking using image or pattern recognition}
- A61B 2034/2068: {using pointers, e.g. pointers having reference marks for determining coordinates of body points}
- A61B 2034/2074: {Interface software}
- A61B 2090/376: {using X-rays, e.g. fluoroscopy}
- A61B 2090/3966: {Radiopaque markers visible in an X-ray image}
- A61F 2002/4658: {for measuring dimensions, e.g. length}
- A61F 2002/4668: {for measuring angles}
- A61F 2002/4681: {by applying mechanical shocks, e.g. by hammering}
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A method is used for aligning an acetabular cup insertion instrument by taking a single lateral view pre-operative digital x-ray of a standing patient's pelvis. The natural pelvic tilt angle is determined by locating an anterior pelvic plane (APP) which is defined by first, second and third points on the anterior of the pelvis and determining the angle between the APP and a coronal plane perpendicular to the surface on which the patient is standing. The patient is then placed on a surface of an operating room table in a supine position. A position tracking device is placed on the patient's pelvis to track movement. Thereafter an operating room navigation or orientation system is used to relocate the APP defined by the first, second and third points. A cup insertion instrument having a position tracking device thereon is oriented using the navigation or orientation system.

## Claims

### Claim 1

A method for aligning an acetabular cup insertion instrument using an x-ray system and an operating room navigation or orientation tracking system, the method comprising:
taking a single lateral pre-operative x-ray image of a standing patient's pelvis with the x-ray system, the single lateral pre-operative x-ray image being in a plane generally aligned with a sagittal plane of the patient perpendicular to a surface on which the patient is standing;
locating an anterior pelvic plane (APP) using the single lateral pre-operative x-ray image, the APP defined by a first point on a pubic symphysis, a second point on a left anterior superior iliac spine and a third point on a right anterior superior iliac spine;
determining, based on the single lateral pre-operative x-ray image, a natural pelvic tilt angle by calculating an angle between the APP and a coronal plane perpendicular to the surface on which the patient is standing;
calculating, using the single lateral pre-operative x-ray image, distances between the first point and the second point, the second point and the third point, and the first point and the third point;
placing the patient on a surface of an operating room table;
placing a first position tracking device on the patient's pelvis to intra-operatively track movement of the pelvis during surgery, wherein the first position tracking device is used to intra-operatively locate the first, second and third points when the patient is on the operating room table, thereafter using the operating room navigation or orientation tracking system to intra-operatively determine the APP defined by the first, second and third points;
using the APP determined intra-operatively in conjunction with the natural pelvic tilt angle determined based on the single lateral pre-operative x-ray image to reproduce the coronal plane; and
using the operating room navigation or orientation tracking system to orient and align the acetabular cup insertion instrument having a second position tracking device mounted thereon at a predetermined anteversion angle with respect to the coronal plane.

### Claim 2 (depends on 1)

The method for aligning an acetabular cup insertion instrument as set forth in claim 1, further comprising defining the sagittal plane through a mid-point between the intra-operatively located second and third points and perpendicular to the coronal plane.

### Claim 3 (depends on 2)

The method for aligning an acetabular cup insertion instrument as set forth in claim 2, further comprising orienting the cup insertion instrument at a predetermined abduction angle with respect to the sagittal plane.

### Claim 4 (depends on 3)

The method for aligning an acetabular cup insertion instrument as set forth in claim 3, wherein the predetermined desired cup abduction and anteversion angles are about 30 to 50 degrees and 10 to 30 degrees respectively.

### Claim 5 (depends on 1)

The method for aligning an acetabular cup insertion instrument as set forth in claim 1, wherein the orientation of the cup insertion instruments is directed by a computer using digital image analysis software receiving input from the single lateral pre-operative x-ray image and the second position tracking device.

### Claim 6 (depends on 1)

The method for aligning an acetabular cup insertion instrument as set forth in claim 1, wherein the single lateral pre-operative x-ray image is a digital x-ray image.