Hip Fixation Deformable Member Load-Controlled Dynamization
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Solution Overview
Problem
Current hip fixation systems either rigidly attach components, leading to femoral shortening or allow excessive movement, neither of which is optimal for effective fracture stabilization and healing.
Innovation Solution
A hip fixation system with load-controlled dynamization, featuring a deformable member that undergoes plastic deformation in response to applied loads, allowing controlled movement and compression of the fracture site, thereby reducing the risk of fixation element cutout and femoral shortening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If components are rigidly attached to allow stable fixation, then fixation stability is improved, but femoral shortening occurs
Solution Approach 1:
The fixation system incorporates a deformable member that allows controlled dynamic movement between components. The deformable member can compress under load, enabling the fixation element to move relative to the support member in a controlled manner, preventing femoral shortening while maintaining stability during the healing process
Solution Approach 2:
The system changes the mechanical parameters of the fixation interface by introducing a deformable member with specific material properties. The deformable member's ability to undergo plastic deformation allows the system to adapt to loading conditions, controlling the relative movement between components and preventing excessive femoral shortening
2Length of moving object
If components are freely slidable to allow movement, then femoral shortening is reduced, but fracture stabilization is compromised
Solution Approach 1:
The deformable member acts as an intermediary element between the fixation element and the support member. It mediates the interaction by providing controlled compliance, allowing limited movement to prevent femoral shortening while maintaining sufficient friction and mechanical interlocking to stabilize the fracture
Solution Approach 2:
The deformable member changes the friction and compliance parameters at the interface between components. By selecting materials and geometries with specific deformation characteristics, the system achieves optimal balance between allowing controlled movement and providing fracture stabilization
3Reliability
If a deformable member is introduced to allow controlled movement, then fixation element cutout is reduced, but device complexity increases
Solution Approach 1:
The deformable member can be implemented as a thin-walled structure or flexible element that provides the necessary compliance. This approach maintains relative simplicity while achieving the desired controlled movement and preventing fixation element cutout through the flexible member's deformation under load
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 effectively stabilizes fractures by allowing controlled movement and compression, reducing the incidence of femoral shortening and fixation element cutout, while accommodating the natural settling of the fracture, thus enhancing the healing process.
Implementation Method 1
a deformable member 60... configured for plastic deformation by deforming contact with a set screw inside the nail in response to a load applied to the system by a subject
Data Source
Figure 1
Figure 2A~2B
Figure 3~6
AI summary
System, including methods and apparatus, for hip fixation with load-controlled dynamization. In exemplary embodiments, the system may comprise a fixation element, such as a screw, configured to be placed into a proximal femur of a subject, with a leading end of the fixation element anchored in a head of the proximal femur. The system also may comprise a stop member configured to be connected (e.g., via a nail or plate) to the proximal femur. The system further may comprise a deformable member configured to be irreversibly deformed by compressive force exerted on at least a portion of the deformable member by the fixation element and the stop member in response to a load applied to the proximal femur by the subject, such that the fixation element and the stop member move relative to one another parallel to a long axis of the fixation element.