Compliant Hip Fixation System for Femoral Head Cut-out Prevention
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Solution Overview
Problem
Current nail-based hip fixation systems for femoral fractures often result in femoral head cut-out due to the screw's inability to maintain stable angular orientation, leading to inadequate load distribution and compromised healing.
Innovation Solution
A compliant hip fixation system featuring an intramedullary nail with a slideable fixation element and a compliant member that deforms reversibly to adjust the angular orientation of the fixation element, reducing peak loads and micro-crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the screw is permitted to slide parallel to its long axis in the nail to enable dynamic compression of the fracture, then fracture healing is improved, but the screw cannot maintain stable angular orientation leading to femoral head cut-out
Solution Approach 1:
The patent applies the dynamics principle by allowing the screw to slide dynamically along the nail's longitudinal axis, enabling the fixation device to adapt to fracture healing requirements. The screw can migrate laterally after installation to provide dynamic compression of the fracture, which encourages and improves fracture healing while maintaining controlled angular orientation through the compliant member.
Solution Approach 2:
The patent applies parameter changes by using a compliant member that can deform reversibly in response to applied loads, changing the angular orientation parameter of the screw relative to the nail. This allows the system to adjust the angular orientation parameter dynamically while maintaining stability, preventing femoral head cut-out through controlled parameter variation rather than fixed rigid positioning.
2Stability of the object's composition
If the screw is fixed with respect to the nail to maintain stable angular orientation, then femoral head cut-out is prevented, but the screw cannot provide dynamic compression of the fracture
Solution Approach 1:
The patent resolves this contradiction by implementing a dynamic sliding mechanism that allows the screw to move along the nail's longitudinal axis. This dynamic capability enables the screw to provide compression forces that promote fracture healing while the compliant member maintains angular orientation stability through reversible deformation, preventing femoral head cut-out.
Solution Approach 2:
The patent introduces a compliant member as an intermediary element between the screw and the nail. This intermediary component allows relative motion and angular adjustment while maintaining overall stability. The compliant member acts as a mediator that transmits loads while permitting controlled deformation, enabling both fracture compression and angular stability simultaneously.
3Object-affected harmful factors
If the compliant member deforms reversibly to change angular orientation of the fixation element, then peak loads and micro-crack formation are reduced, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by incorporating a compliant member that can deform reversibly in response to applied loads, dynamically adjusting the angular orientation parameter of the fixation element. This parameter change capability reduces peak loads and micro-crack formation at the bone-implant interface by allowing controlled motion and load distribution, while the modular design keeps device complexity manageable.
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
The system reduces the incidence of femoral head cut-out, enhances patient comfort, and improves force dampening, leading to better healing outcomes and reduced wear-related issues.
Implementation Method 1
a compliant member located in the nail and configured to deform reversibly in response to a load applied to the head of the proximal femur by the subject after the nail and the fixation member have been implanted in the proximal femur of the subject, to reversibly change an angular orientation of the fixation element with respect to the nail
Data Source
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AI summary
System, including methods, devices, and kits, for hip fixation. The system may comprise an intramedullary nail configured to be placed longitudinally into a proximal femur. The system also may comprise a fixation element configured to be placed transversely through the nail, such that the fixation element is slideable along its long axis in the nail and extends out of the nail to a head of the proximal femur and is anchored in the head. A compliant member may be located in the nail and configured to deform reversibly in response to a load applied to the head of the proximal femur after placement of the fixation element, to reversibly change an angular orientation of the fixation element with respect to the nail.