The effect of c-arm tilt on accuracy of intraoperative fluoroscopy in assessing acetabular component position during direct anterior approach for hip arthroplasty.

Jang, Eugene S; Lin, James D; Shah, Roshan P; Geller, Jeffrey A; Cooper, H John · J Orthop · 2018

biomechanical · Level V

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Abstract

Intraoperative fluoroscopy can improve the precision of acetabular component positioning during direct anterior hip arthroplasty. However, changes in pelvic tilt with c-arm positioning may compromise accuracy. A geometric model of an acetabular component's projection onto fluoroscopy images was created and manipulated to simulate c-arm tilt. An apparently ideally-placed cup will have its effective anteversion changed by 7.5° with just 10° of caudal/cephalad tilt of the c-arm. This effect is greater in cups that are more horizontally placed or less anteverted. Accurate c-arm positioning is crucial, as small errors in tilt can have considerable effects on final cup position.

Anatomy