Does Degree of the Pelvic Deformity Affect the Accuracy of Computed Tomography-Based Hip Navigation?

Abstract

Abstract:Some navigation systems have been used for improvement of component positioning, there have been few reports regarding cases of severe pelvic deformity. We performed a retrospective review of 25 cases of THA with a computed tomography (CT)-based navigation system in patients with severe pelvic deformities and estimated acetabular component position and angle between severe deformity group and mild dysplastic group as a control. There were no significant differences in accuracy of navigation system between two groups in terms of three-dimensional component position or angle. Accuracy of CT-based hip navigation does not depend on the degree of pelvic deformity, and this system is also useful to identify acetabular orientation and for precise component implantation in cases of pelvic deformity. Keywords:total hip arthroplasty, pelvic deformity, computed tomography (CT)-based navigation system, acetabular component, developmental dysplasia. Brief title:Hip Navigation in Severe Pelvic Deformity mild dysplastic group as a control. There were no significant differences in accuracy of navigation system 10 between two groups in terms of three-dimensional component position or angle. Accuracy of CT-based 11 hip navigation does not depend on the degree of pelvic deformity, and this system is also useful to 12 identify acetabular orientation and for precise component implantation in cases of pelvic deformity.

The value of computed tomography based navigation in revision total hip arthroplasty

“…The same navigation system was used in all operations (CT-based Hip, version 1.0; Stryker Navigation, Freiburg, Germany). Data for the control group was reported in 2012 following similar criteria [6]. Patient demographics are shown in Table 1.…”

“…The anterior pelvic plane defined by both the bilateral anterior superior iliac spine and pubic tubercle was used as the reference plane of the pelvis. If, due to spine and pelvic deformities, the pelvis was tilted in the sagittal plane when the patient was lying in a supine position, correction of the anterior-posterior axis was performed during pre-operative templating, as described in previous studies [6,24]. In brief, the functional pelvic plane was used as a reference plane [14] for both groups.…”

“…We manually established the same coordinate plane as that determined in pre-operative planning and measured various parameters so that virtual computeraided-design models of the acetabular component could be superimposed on the images of the actual implanted component (Fig. 2) [6]. We evaluated the deviation of radiographic anteversion and inclination angle among the pre-operative plan, intraoperative records from the navigation system and data from postoperative CT scans.…”

“…As reported previously, we used the functional pelvic zero position to measure cup orientation (inclination and anteversion): the pelvis, with the patient in a supine position on the CT scan table, was axially rotated until the bilateral anterior iliac spines touched the same horizontal plane; then, the interteardrop line was used as the mediolateral axis [6,23]. We manually established the same coordinate plane as that determined in pre-operative planning and measured various parameters so that virtual computeraided-design models of the acetabular component could be superimposed on the images of the actual implanted component (Fig.…”

“…Malpositioning of the acetabular component in both primary and revision THA increases the risk of reduced range of movement (ROM), with an increase in dislocation, impingement, prosthesis wear and osteolysis, and effect on long-term results [2,6,19]. Revision THA is a technically demanding procedure, and the risk of postoperative dislocation is high [8,17].…”