THA After Osteotomy

As in conventional THA, the bony coverage and height of the acetabular cup are considered when determining the implant placement position. Computed tomography (CT) is recommended because of the possibility of an anteroposterior acetabular wall defect. In cases where the height of the joint is elevated, if the original acetabular position is maintained, a bulky bone graft may be required at the loading site, which may cause problems with the fixation of the acetabular cup. The author uses the cup-center edge (CE) angle (0° or greater) [1] and the distance from the inferior edge of the tear drop to the center of the head (approximately within 30 mm) [2–4] as guidelines for placement (Fig. 76.1).