Tibial Exit Point Navigation for ACL Implant Collision Avoidance
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Solution Overview
Problem
Current methods for positioning the exit point of an anterior cruciate ligament implant on the tibia fail to ensure a free path for the implant in all knee positions, risking collision with femur bone structures during movement.
Innovation Solution
A navigation system determines positional data for both the tibia and femur, projecting the femur's front edge notch onto a perpendicular plane on the tibia, selecting an exit point within a circular area that maintains a safe distance from the projected curve to avoid collisions with femur structures, ensuring the implant's stability and non-contact with bone tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tibial exit point is chosen based on surgeon experience, then the positioning process is simple, but the implant may collide with femur bone structures during knee movement
Solution Approach 1:
The patent replaces the manual surgeon experience-based positioning method with a computer-based navigation system that uses optical tracking and geometric calculations to determine the optimal tibial exit point, thereby eliminating the risk of implant collision with bone structures
Solution Approach 2:
The system performs preliminary geometric calculations and simulations before the actual implantation to identify the safe exit point location, allowing the surgeon to proceed with confidence that the implant will not collide with femur structures during knee movement
2Reliability
If the exit point is positioned to ensure free path in all knee positions, then collision with bone structures is avoided, but the positioning complexity increases
Solution Approach 1:
The patent introduces a computer-based navigation system as an intermediary between the surgeon and the implantation process, handling the complex geometric calculations and simulations to determine the optimal exit point, thereby reducing the burden on the surgeon while ensuring reliable collision avoidance
Solution Approach 2:
The system uses three-dimensional geometric modeling and multi-planar projections to analyze the complex spatial relationships between the implant path and bone structures, transforming a difficult three-dimensional positioning problem into manageable two-dimensional visual representations for the surgeon
Data Source
AI summary
In order to establish an optimum position on the upper side of the tibia for the exit point of an anterior cruciate ligament replacement, it is proposed that, with the leg bent, the position of a number of points along the front edge of the notch is detected and in this way their position and progression on the femur are also determined, that, with the leg straight, the course of this front edge of the notch is projected onto a projection plane which is perpendicular to the longitudinal axis of the tibia in the region of the upper side of the tibia, and that, within the region enclosed by this projected curve, the exit point is selected such that it maintains at least a distance corresponding to the radius of the implant from the projected curve. Furthermore, an apparatus for carrying out such a method is proposed.