External Fixator Half-Ring Pivoting for Foot Deformity Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing external fixation systems for bone deformities, particularly foot fixation systems, lack flexibility and motion, making it difficult for patients to adjust the frame daily and limiting optimal clinical outcomes during deformity correction.
Innovation Solution
An external fixation frame design featuring a first and second fixation ring connected by adjustable struts with universal and constrained hinge joints, allowing for pivoting and adjustment of a half-ring assembly, which includes a rocker member for improved accessibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a solid and stationary half-ring is assembled to the foot ring, then structural stability is improved, but flexibility and motion are reduced
Solution Approach 1:
The patent applies the dynamics principle by replacing the solid stationary half-ring with a dynamic assembly that includes a pivoting half-ring connected through a universal joint. This allows the structure to adapt its configuration during deformity correction while maintaining stability when needed. The universal joint enables rotational movement, transforming the static structure into a dynamic one that can accommodate both stability and flexibility requirements.
Solution Approach 2:
The patent segments the previously solid half-ring into separate components: a pivoting half-ring assembly and a universal joint. This segmentation allows independent optimization of each component - the half-ring provides structural stability while the universal joint provides flexibility and motion capability, resolving the contradiction between these two requirements.
2Strength
If adjustment points are located between the ends of struts, then structural integrity is maintained, but patient accessibility for daily adjustments is reduced
Solution Approach 1:
The patent resolves this contradiction by moving the adjustment mechanism from the traditional location between strut ends to the distal end of the struts. This dimensional repositioning places the adjustment point in a more accessible location for patients while maintaining structural integrity through the universal joint design that distributes loads appropriately across the joint components.
Solution Approach 2:
The universal joint acts as an intermediary element that allows adjustment access at the distal end while maintaining structural integrity. It mediates between the patient's need for easy access and the structural requirement for strength, enabling adjustments without compromising the overall structural integrity of the fixation frame.
3Device complexity
If manual adjustment with wrench or by hand is used, then device complexity is minimized, but ease of operation for daily adjustments is reduced
Solution Approach 1:
The patent implements self-service by designing the universal joint with an integrated adjustment mechanism that patients can operate independently. The joint allows for tool-free or simplified adjustments, enabling patients to perform daily adjustments themselves without requiring complex tools or assistance, thus improving ease of operation while keeping the device relatively simple.
Solution Approach 2:
The dynamic universal joint design incorporates movable components that facilitate easier adjustment operations. The joint's inherent mechanical design allows for smoother and more accessible adjustments compared to fixed nut-and-bolt systems, improving ease of operation without significantly increasing device complexity.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An external fixation frame for correcting a bone deformity includes a first fixation ring (101) and a second fixation ring (102). Medial and lateral adjustable length struts (103b) couple medial and lateral portions of the first fixation ring (101) to medial and lateral portions of the second fixation ring (102) respectively. The fixation frame also includes a half ring (113) hingedly coupled to the second fixation ring.