Depuy International Limited

Depuy Orthopaedics, Inc.

Johnson & Johnson Medical Gmbh

Frank Foley

Alec Paul Birkbeck

Ian Crawford Revie

Thorsten M Burger

Michal Slomczykowski

David Beverland

Brian Griffiths

Mike Slomczykowski

Ben Stungo

Ian Revie

A computer assisted surgery method and apparatus for determining a change in a property of a joint of a patient caused by an arthroplasty procedure is described. The relative position of a first bone and a second bone of the joint is determined with the joint in a first position. The position of a pre-operative center of motion of the joint relative to the first bone is determined. The position of the second bone relative to the pre-operative center of motion is determined using the relative position of the first and second bones. The position of a post-operative center of motion resulting from a prosthetic component to be used in the joint is determined. The position of the second bone relative to the post-operative center of motion is determined. Any change in the property of the joint. is determined from the difference between the position of the second bone relative to the pre-operative center of motion and the position of the second bone relative to the post-operative center of motion.

Surgical apparatus and procedure

A computer aided surgery system, method, surgical method and instrument for guiding the positioning of an acetabular cup in a pelvis are described. The position of the transverse acetabular ligament of the pelvis and the position of the acetabular labrum of the pelvis are determined. The orientation of an acetabular plane including the acetabular labrum and the transverse acetabular ligament is calculated. A planned position for the acetabular cup is determined, in which an inlet plane of the cup is substantially parallel to the acetabular plane. The instrument comprises a mounting for attaching the instrument to a patient, a support, a guide defining a longitudinal axis, and for receiving a further instrument bearing the acetabular cup implant, and an adjustment mechanism. The adjustment mechanism can allow the angular orientation of the guide to be adjusted about at least two different axes to allow the inclination and version or anteversion of the longitudinal axis to be altered.

Acetabular cup positioning

A handle assembly (,) has a handle body (,), an arm (,) and a trigger mechanism (,). The handle body (,) has a recess (,) for receiving an instrument to be held by the handle assembly (,). The arm (,) pivots in relation to the handle body (,) and the trigger mechanism (,) holds the arm (,) in two positions relative to the handle body (,). A third position enables the arm (,) to be detached from the handle body (,). In the first position, the arm (,) is locked adjacent the handle body (,) such that a projection (,) from the arm (,) engages the recess (,) in which a neck of an instrument being held can be inserted.

Handle assembly

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Leeds, United Kingdom

Frank Foley