Pelvic Implant Placement Using Combined Anteversion Navigation
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Solution Overview
Problem
Conventional methods for positioning hip implants do not adequately account for individual variations in hip mechanics and stability, leading to potential impingement and dislocation issues due to inaccuracies in pelvic tilt and anteversion alignment.
Innovation Solution
The method involves planning the placement of the cup and femoral stem using the principle of combined anteversion, where the anteversion angle of one component is dependent on the other, utilizing medical navigation systems to achieve a predetermined combined anteversion angle between 30 and 45 degrees, thereby minimizing impingement through precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to position hip implants based on subjective assessment and arbitrary planes, then the surgical procedure is simpler and faster, but the alignment precision and reliability of the implant positioning deteriorate
Solution Approach 1:
The patent replaces subjective mechanical assessment methods with an optical-mechanical navigation system that uses cameras, trackers, and computer algorithms to objectively measure and guide implant positioning. The system substitutes the surgeon's subjective judgment with automated computational analysis of anatomical landmarks and implant orientation.
Solution Approach 2:
The navigation system acts as an intermediary between the surgeon and the implant positioning process. It provides real-time feedback on cup and stem alignment, allowing the surgeon to make precise adjustments based on objective data rather than relying solely on experience and subjective assessment.
2Measurement precision
If navigation systems reference the anterior pelvic plane without accounting for pelvic tilt, then the cup positioning is simplified, but the accuracy of anteversion angle measurement deteriorates due to pelvic tilt variations
Solution Approach 1:
The system dynamically adjusts the reference plane parameters based on measured pelvic tilt angles. Instead of using a fixed anterior pelvic plane, the navigation system calculates and applies compensation angles to account for individual patient variations in pelvic tilt, thereby improving the accuracy of cup anteversion measurement.
Solution Approach 2:
The navigation system transitions from a static reference plane approach to a dynamic one that adapts to each patient's anatomy. The system continuously monitors and adjusts for pelvic tilt variations, allowing the reference frame to move and rotate with the patient's specific anatomical configuration rather than relying on a standardized fixed plane.
3Ease of operation
If the cup and stem are positioned without considering combined anteversion, then the surgical procedure is more straightforward, but the range of motion and stability of the artificial hip joint deteriorate
Solution Approach 1:
The navigation system provides real-time feedback on the combined anteversion of the cup and stem components. The surgeon receives continuous information about how the positioning of one component affects the overall alignment, allowing for iterative adjustments to achieve the target combined anteversion angle for optimal joint stability and range of motion.
Solution Approach 2:
The system allows for preliminary planning of the combined anteversion target before actual implantation. The surgeon can pre-calculate the desired relationship between cup and stem anteversion angles based on patient-specific anatomy and joint mechanics, then use this plan to guide the positioning process rather than relying on intraoperative trial-and-error.
Data Source
AI summary
A method for placing a pelvic implant including a cup and a femoral stem includes planning at least one of a location of the cup within a pelvis and a location of the stem within a femur such that a combined anteversion between a predetermined cup component and a predetermined femoral stem component satisfies a predetermined combined anteversion.