Intraoperative Acetabular Cup Anteversion Measurement via C-arm Tilt
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Solution Overview
Problem
Current methods for determining acetabular cup anteversion during total hip arthroplasty, especially in the direct anterior approach with the patient in a supine position, are inadequate as they rely on complex and time-consuming image-based navigation techniques or lack precision in intraoperative fluoroscopy assessments.
Innovation Solution
A fluoroscopy-based system that measures intraoperative acetabular cup anteversion by positioning a C-arm perpendicular to the patient, determining the abduction angle, adjusting the C-arm tilt to make the acetabular cup rim appear linear, and using the measured angles to calculate the anteversion angle through a specific equation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image-based navigation techniques are used to determine acetabular cup anteversion, then measurement precision is improved, but device complexity and surgery time increase
Solution Approach 1:
The patent extracts only the essential measurement function from complex navigation systems by using simple fluoroscopic imaging combined with geometric calculations based on the known C-arm tilt angle, eliminating the need for complex optical trackers and registration procedures while maintaining measurement capability
Solution Approach 2:
The patent creates a geometric model copy of the acetabular cup orientation relationships that can be calculated from 2D fluoroscopic images, allowing accurate anteversion determination without requiring complex 3D navigation hardware
2Measurement precision
If image-based navigation techniques are used to determine acetabular cup anteversion, then measurement precision is improved, but surgery time increases
Solution Approach 1:
The patent incorporates the C-arm tilt angle measurement as a preliminary action that is performed once and then used in the geometric calculation of anteversion, eliminating the need for time-consuming repeated measurements and complex navigation setup procedures
Solution Approach 2:
The patent replaces complex mechanical navigation systems with mathematical geometric calculations that can be performed rapidly using standard fluoroscopic images and the predetermined C-arm tilt angle
3Productivity
If conventional fluoroscopy assessment is used to determine acetabular cup position, then surgery time is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent changes the measurement parameter from direct visual assessment of 2D images to calculated 3D orientation parameters using the geometric relationship between the C-arm tilt angle and cup orientation, enabling precise anteversion measurement while maintaining surgical efficiency
4Measurement precision
If standardized AP pelvic films are used to assess anteversion, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent makes the fluoroscopy system itself provide the necessary tilt angle information through its positioning mechanism, eliminating the need for separate standardized film acquisitions and complex positioning procedures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method provides accurate and reproducible acetabular component anteversion measurements comparable to CT-scan imaging, reducing surgery time and radiation exposure while improving acetabular cup positioning accuracy.
Implementation Method 1
fluoroscopy is a type of medical imaging that shows a continuous X-ray image on a display (monitor), much like an X-ray movie. During a fluoroscopy procedure, an X-ray beam is passed through the body
Data Source
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AI summary
Direct anterior approach (DAA) with the patient lying supine has facilitated the use of intraoperative fluoroscopy and allows for standardized positioning of the patient. The method disclosed herein uses intraoperative fluoroscopy to measure acetabular component anteversion and more particularly, a method for measuring/calculating intraoperative cup (acetabular component) anteversion is provided based on the measured acetabular component abduction angle and a c-arm tilt angle (CaT).