Patent ID: 7338499
Filing Date: 2008-03-04
Classification: A61B,A61F

Abstract:
1. Apparatus for interoperatively determining, during a trialing procedure conducted in connection with total hip arthroplasty at an implant site, a femoral neck length required along a predetermined direction in a femoral component to be engaged with an acetabular component in a prosthetic hip joint to be implanted at the implant site for establishing forces appropriate for proper articular engagement of the femoral component with the acetabular component, the apparatus comprising: a femoral trial for placement at the implant site, the femoral trial including a trial femoral head component and a trial femoral stem component, the femoral neck length being determined by determining a measured distance corresponding to a trial distance between the trial femoral head component and the trial femoral stem component of the femoral trial when the femoral trial is placed at the implant site with the trial femoral head component engaged with an acetabular trial, at which trial distance soft tissue at the implant site is tensioned to establish selected tensile forces in the soft tissue for urging the trial femoral head component into engagement with the acetabular trial, the selected tensile forces corresponding to the forces appropriate for proper articular engagement of the femoral component with the acetabular component, and the trial distance corresponding to the required femoral neck length; a connecting arrangement for connecting the trial femoral head component with the trial femoral stem component, the connecting arrangement being dimensioned and configured for selective movement of the trial femoral head component and the trial femoral stem component relative to one another in the femoral trial, during the trialing procedure, through trial distances relative to one another along a direction of movement corresponding to the predetermined direction of the femoral neck length with the trial femoral head component and the trial femoral stem component connected to one another; a distance indicator for indicating measured distances corresponding to the trial distances established between the trial femoral head component and the trial femoral stem component along the direction of movement during the trialing procedure; and a force applier dimensioned and configured for coupling with the trial femoral head component and the trial femoral stem component of the femoral trial to apply selected forces urging the trial femoral head component and the trial femoral stem component away from one another and establish the trial distances at measured distances indicated by the distance indicator such that upon coupling of the force applier with the femoral trial and applying the selected forces while the trial femoral head component is engaged with the acetabular trial to urge the trial femoral head component and the trial femoral stem component away from one another and tension the soft tissue during the trialing procedure, a measured distance corresponding to a trial distance at which the selected tensile forces are established in the soft tissue is determined interoperatively, thereby determining interoperatively the femoral neck length required in the femoral component for establishing the forces appropriate for proper articular engagement of the femoral component with the acetabular component.