Tailor‐made surgical guide based on rapid prototyping technique for cup insertion in total hip arthroplasty

Abstract

We can use this guide with acceptable accuracy and without consuming an excessive amount of time.

Tailor-made Surgical Guide Reduces Incidence of Outliers of Cup Placement

“…A coordinate system when taking the preoperative CT images was adjusted by a line joining the bilateral bottoms of the ischium in the coronal DRR view. Then, the adjusted pelvic coordinate system was defined as the preoperative pelvic coordinate system [10]. Alignment of the cup was referenced by the radiographic definition [19]: abduction was defined as an angle difference between the face of the cup and horizontal axis in the coronal view, and anteversion was defined as the angle between the acetabular axis and the coronal plane.…”

“…Alignment of the cup was referenced by the radiographic definition [19]: abduction was defined as an angle difference between the face of the cup and horizontal axis in the coronal view, and anteversion was defined as the angle between the acetabular axis and the coronal plane. Alignment of each cup was planned at 40°f or abduction; anteversion was planned using a range between 15°and 20°, because acetabular bony coverage and degree of femoral neck anteversion were considered [10]. These angles were defined as the preoperative cup orientation.…”

“…We also recorded pelvic rotation on the axial MPR view, which is the angle between the line joining the bilateral anterior superior iliac spines and the horizontal line [10]. The CT images were transferred to image processing software (Virtual Place-M; Medical Imaging Laboratory, Tokyo, Japan) to reconstruct a polygonal three-dimensional pelvic model using the Marching Cubes method [17].…”

“…The pelvic coordinate system of the postoperative CT images was determined using our method. The postoperative pelvic coordinate system then was adjusted to match with the preoperative pelvic coordinate system using the pelvic tilt and rotation of the preoperative pelvic coordinate system [10]. The alignment of the cup that was measured after this modification was defined as postoperative orientation of the cup.…”

“…To address the additional time of the concerns, we developed a tailor-made surgical guide produced using a rapid prototyping (RP) technique for cup insertion surgery [10]. Like other tailor-made surgical guides [2,3,9,23], the surgical guide has a base part that fits on the bone intraoperatively and a guide part to achieve preoperatively planned alignment of the component on the basis of preoperative computed tomography (CT) images.…”