A precise method for determining acetabular component anteversion after total hip arthroplasty

Abstract

Aims Several radiological methods of measuring anteversion of the acetabular component after total hip arthroplasty (THA) have been described. These are limited by low reproducibility, are less accurate than CT 3D reconstruction, and are cumbersome to use. These methods also partly rely on the identification of obscured radiological borders of the component. We propose two novel methods, the Area and Orthogonal methods, which have been designed to maximize use of readily identifiable points while maintaining the same trigonometric principles. Patients and Methods A retrospective study of plain radiographs was conducted on 160 hips of 141 patients who had undergone primary THA. We compared the reliability and accuracy of the Area and Orthogonal methods with two of the current leading methods: those of Widmer and Lewinnek, respectively. Results The 160 anteroposterior pelvis films revealed that the proposed Area method was statistically different from those described by Widmer and Lewinnek (p < 0.001 and p = 0.004, respectively). They gave the highest inter- and intraobserver reliability (0.992 and 0.998, respectively), and took less time (27.50 seconds (sd 3.19); p < 0.001) to complete. In addition, 21 available CT 3D reconstructions revealed the Area method achieved the highest Pearson’s correlation coefficient (r = 0.956; p < 0.001) and least statistical difference (p = 0.704) from CT with a mean within 1° of CT-3D reconstruction between ranges of 1° to 30° of measured radiological anteversion. Conclusion Our results support the proposed Area method to be the most reliable, accurate, and speedy. They did not support any statistical superiority of the proposed Orthogonal method to that of the Widmer or Lewinnek method. Cite this article: Bone Joint J 2019;101-B:1042–1049.

Usefulness of intraoperative C-arm image intensifier in reducing errors of acetabular component during primary total hip arthroplasty: an application of Widmer’s method

“…Measuring the anteversion of acetabular component is more difficult to measure than inclination. There are several methods and also, other Area and Orthogonal methods have been introduced [ 32 ]. However, these methods used to focus on measuring the version after surgery.…”

Usefulness of Intraoperative C-Arm Image Intensifier in Reducing Errors of Acetabular Component During Primary Total Hip Arthroplasty: An Application of Widmer’s Method

“…Measuring the anteversion of acetabular component is more di cult to measure than inclination. There are several methods and also, other Area and Orthogonal methods have been introduced [30]. However, these methods used to focus on measuring the version after surgery.…”

The area method for measuring acetabular cup anteversion: An accurate and autonomous solution

“…The femoral head and acetabular cup were then identified via the program and its area used to calculate the anteversion as previously described. 16 Secondly, a machine learning algorithm was developed to outline the border of the femoral head and acetabular cup. To do so, 15,000 training images were independently fabricated to resemble a post-operative AP pelvis radiograph.…”

“…This method identifies anteversion with the points dependent on the radiopaque border of the femoral head-acetabular cup region. 16 This methodology is opportune to apply computational automation in calculating cup orientation given the stark difference in intensity between the radiopaque implant and more radiolucent bony and soft tissues.…”

“…This study aims to test the recently proposed Area method 16 as a method applicable to autonomous identification of acetabular component orientation. This study will also further test the accuracy of the Area method against true anteversion, as measured by a triaxial accelerometer.…”