External Fixation Ring Hole Layout for Extended Strut Correction
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Solution Overview
Problem
Existing external fixation systems for bone deformities are limited by default strut mounting positions that restrict the maximum range of motion between fixation rings, making it difficult to correct severe deformities and requiring additional struts or complex procedures when struts reach their maximum length.
Innovation Solution
A method and system that allows for alternative strut mounting positions on fixation rings, determined through a series of simulations, to increase the range of motion and avoid the need for strut replacement by adjusting strut positions without adding new struts, using a staggered hole configuration on the rings to facilitate further length adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If struts are mounted at default positions on fixation rings, then the fixation frame structure is simple and stable, but the range of motion between rings is limited and severe deformities cannot be corrected
Solution Approach 1:
The fixation ring is segmented into multiple discrete mounting positions (holes) around its circumference, allowing struts to be attached at different locations. This segmentation enables the system to achieve various angulations and ranges of motion by selecting appropriate mounting positions, directly resolving the contradiction between adaptability and structural simplicity.
Solution Approach 2:
The mounting positions are designed to be adjustable and reconfigurable rather than fixed. Struts can be removed and reattached at different holes on the rings, allowing the fixation frame to dynamically adapt to different correction needs. This dynamic capability enables correction of severe deformities while maintaining a relatively simple overall structure.
2Adaptability or versatility
If alternative mounting positions are used to increase range of motion, then severe deformities can be corrected, but strut angles increase which reduces fixation frame stability
Solution Approach 1:
Different mounting positions on the rings are designed with specific local characteristics - the distribution and positioning of holes are optimized to provide both range of motion and stability. By carefully placing holes at specific locations around the ring circumference, the system achieves local optimization that allows severe deformity correction while maintaining overall structural stability.
Solution Approach 2:
The system allows changing the mounting position parameters (which hole to use) to optimize both range of motion and stability. By adjusting the specific hole positions selected for strut attachment, clinicians can find the optimal balance between achieving the needed correction angle and maintaining fixation stability, directly addressing the contradiction between adaptability and stability.
Data Source
AI summary
An external fixation system includes first and second fixation members having first and second pluralities of mounting holes, respectively. The first and second plurality of holes are configured to receive first and second ends of a plurality of struts, each strut having a default or initial mounting position. A simulation of the correction may be performed with the struts in the default positions, but it may be determined that the correction is not achievable. Additional simulations of the correction may be performed with the ends of the struts in different mounting positions to determine if other mounting positions of the struts allow the correction to be completed. During the correction, if one of the struts reaches a maximum length, it may be disconnected and reconnected to a different mounting hole so that, after being reconnected, the strut may be further increased in length to continue the correction.