Orthopedic Spring Hinge for Shifting Joint Axis Stability
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Solution Overview
Problem
Existing orthopedic hinges used in external fixation systems lack sufficient stability and fail to dynamically adapt to the shifting anatomical axis of rotation, leading to potential joint damage and discomfort due to excessive movement along unwanted axes.
Innovation Solution
The development of orthopedic spring hinges that allow pivotal movement about an anatomical joint while reducing or preventing unwanted translational or shearing movement, featuring coil springs with varying physical and mechanical properties to limit movement to a finite number of planes and dynamically adapt to the shifting anatomical axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional coil springs are used in hinges to allow the axis of rotation to shift, then adaptability to anatomical axis is improved, but stability is worsened due to inherent instability and shearing forces
Solution Approach 1:
The spring is divided into multiple coils that can independently deform, allowing the hinge to adapt to anatomical axis shifts while maintaining overall stability. Each coil acts as an independent element that can absorb shear forces without compromising the entire structure.
Solution Approach 2:
The hinge combines spring elements with rigid structural components to create a composite system. The spring provides adaptability to anatomical variations, while the rigid components maintain stability and prevent excessive shearing movement.
2Device complexity
If traditional mono-axial mechanical hinges are used, then structural simplicity is improved, but adaptability to shifting anatomical axis is worsened
Solution Approach 1:
The hinge transitions from a static mono-axial mechanical structure to a dynamic spring-based structure that can adapt its configuration. The spring allows the axis of rotation to shift dynamically to match the anatomical axis while maintaining a relatively simple overall structure.
Solution Approach 2:
The hinge utilizes changes in spring parameters (coil spacing, wire diameter, mean coil diameter) to achieve adaptability to different anatomical configurations. By modifying these physical parameters, the hinge can accommodate shifting anatomical axes without requiring complex mechanical adjustments.
3Stability of the object's composition
If coil springs with varying physical properties are used, then stability and movement control are improved, but device complexity increases
Solution Approach 1:
Different sections of the spring have varying physical properties (coil spacing, wire diameter, mean coil diameter) to provide localized control over movement. The first, second, and third coils have different characteristics that collectively provide stability while allowing controlled adaptation to anatomical variations.
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 solution provides enhanced stability and alignment with the anatomical axis, reducing joint damage and discomfort by limiting movement to desired planes and accommodating dynamic shifts, thereby facilitating effective bone healing and mobility.
Implementation Method 1
A first coil spring can have a first bending resistance and a second coil spring can have a second bending resistance that is less than the first bending resistance
Implementation Method 2
When a joint rotates or moves, the corresponding axis of rotation may shift in one or more directions... traditional coil springs may fail to provide sufficient stability when used in external fixation systems
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An orthopedic spring hinge and associated external fixation systems for the treatment of anatomical joint dysfunctions, and more particularly, to a spring hinge comprising a first base member, a second base member, a flexible first spring having a first longitudinal axis extending from the first base member to the second base member, and a flexible second spring spaced apart from the first spring and having a second longitudinal axis extending from the first base member to the second base member. The spring hinge is configured to have a maximum bending resistance in a first plane extending between the first spring and the second spring and a minimum bending resistance in a second plane orthogonal to the first plane.