Orthopedic Spring Hinge With Nested Coils for Shear Stability
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Solution Overview
Problem
Traditional orthopedic hinges, such as mechanical pin hinges and springs, fail to provide sufficient stability and adaptability to the dynamic anatomical axis of rotation, leading to unwanted translational or shearing movements that can impair joint healing and cause pain or damage during external fixation procedures.
Innovation Solution
A spring hinge with a primary coil spring having a helical structure and a central cavity, featuring nested convex and concave profiles to resist shearing movement, and optionally a secondary coil spring to stabilize the primary coil spring, allowing for pivotal movement while preventing unwanted translational or shearing movements, and dynamically adapting to the anatomical axis of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional mechanical pin hinges are used, then the hinge provides a fixed axis of rotation, but it cannot adapt to the dynamic anatomical axis of rotation, causing misalignment and potential joint damage
Solution Approach 1:
The patent replaces the static mechanical pin hinge with a dynamic spring-based hinge system. The spring mechanism allows the axis of rotation to dynamically adjust and adapt to the changing anatomical axis during joint movement, while maintaining reliable connection through the elastic properties of the spring and complementary geometric profiles.
Solution Approach 2:
The patent changes the physical state and properties of the hinge from rigid and fixed to elastic and adaptable. By using spring elements with specific force constants and geometric profiles, the system can change its rotational parameters dynamically to match anatomical requirements while maintaining stability through controlled elastic deformation.
2Adaptability or versatility
If traditional springs are used as hinges, then the hinge allows dynamic adjustment to anatomical axis, but it exhibits higher instability and unwanted translational or shearing movement
Solution Approach 1:
The patent employs nested spring elements where an inner spring is positioned within an outer spring. This nested configuration provides dynamic adaptability through the spring mechanism while the outer spring contains and stabilizes the inner spring, preventing unwanted translational or shearing movements through geometric constraints and complementary profiles.
Solution Approach 2:
The patent creates a composite hinge system combining multiple spring elements with different geometric profiles (convex and concave surfaces) and material properties. This composite structure integrates the dynamic adjustment capability of springs with the stability provided by geometric interlocking and complementary profiles, eliminating the instability of traditional single-spring designs.
3Ease of operation
If a spring hinge allows pivotal movement, then it provides controlled motion to the joint, but it may permit translational or shearing movement that can harm the joint
Solution Approach 1:
The patent incorporates geometric profiles (convex and concave surfaces) that preemptively prevent harmful translational or shearing movements before they can occur. These profiles are designed to constrain motion to the desired rotational plane, creating preliminary geometric barriers that block any potential joint-damaging movements while allowing controlled pivotal motion.
Solution Approach 2:
The spring mechanism acts as an intermediary between the fixed external fixator and the moving joint. It transmits controlled pivotal motion while filtering out harmful translational or shearing components through its elastic properties and geometric constraints, protecting the joint from damage while maintaining ease of operation.
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 spring hinge provides stable and controlled pivotal movement about anatomical joints, reducing the risk of injury and enhancing the healing process by aligning with the shifting anatomical axis of rotation, thus improving joint mobility and reducing the risk of pain or damage.
Implementation Method 1
a primary coil spring having a helical structure with a central cavity, wherein the primary coil spring forms a plurality of spirals layered against one another when the primary coil spring is in an unexpanded state
Implementation Method 2
a portion of the first surface with the convex profile is configured to nest against an adjacent portion of the second surface with the concave profile when the primary coil spring is in an unexpanded state, and wherein the nested convex and concave profiles resist a shearing movement between the first surface and the second surface
Data Source
AI summary
A device, kit, and method for the treatment of anatomical joint dysfunctions, and more particularly, to a spring hinge comprising: a primary coil spring having a helical structure with a central cavity, wherein the primary coil spring forms a plurality of spirals layered against one another when the primary coil spring is in an unexpanded state; wherein the primary coil spring comprises surfaces that are configured to nest against each other to resist translational or shearing movement between adjoining spiral layers.