EOS

Templating

AimTHR Templating

 

Reproduce the normal anatomical centre of rotation

Restore femoral offset 

Maintain equal leg lengths 

 

Usually template off normal hip

 

Template

 

1. LLD

2. Offset

3. Femoral component

4. Acetabular component

5. Osteotomy / femoral seating

 

Offset

Definition

 

The perpendicular distance from the centre of the femoral head to the long axis of the femur

 

Harris 1992

- aim for supra-physiologic offset 

- avoid making offset less than original at all costs & makes longer if possible

 

Soft tissue balancing equals restoring femoral offset

 

Effect of short offset

 

1.  Abductor lurch / Trendelenburg gait