Ratcheting External Fixation Assembly for Controlled Bone Compression
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Solution Overview
Problem
Existing external fixation systems face challenges such as risk to anatomic structures, potential infection, joint contractures, prolonged bone healing, and reliance on patient compliance during distraction osteogenesis, while also lacking the ability to provide temporary fixation with compression or distraction options.
Innovation Solution
An external fixation system comprising elongate rods with ratchet ends and fixation members, allowing for manual or motorized compression or distraction of adjacent bone portions, featuring a ratchet assembly and polyaxial screws for secure attachment, and optionally using octagonal rods for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional external fixation systems are used, then bone stabilization is achieved, but the risk of infection and damage to anatomic structures increases
Solution Approach 1:
The external fixation system is divided into separate modular components including fixation members, elongate rods, and connection assemblies. This segmentation allows each component to be optimized independently and reduces the complexity of the overall system, thereby reducing potential infection risks while maintaining reliable bone stabilization.
Solution Approach 2:
The elongate rod acts as an intermediary element between the fixation members inserted into the bone and the external adjustment mechanism. This intermediary structure allows external control of compression and distraction forces without requiring direct penetration or exposure of critical anatomic structures, reducing infection risk while maintaining stabilization reliability.
2Length of moving object
If distraction osteogenesis is performed using external fixation, then bone lengthening is achieved, but patient compliance becomes critical and healing time extends
Solution Approach 1:
The connection assembly incorporates a dynamic ratchet mechanism that allows controlled, incremental adjustment of the distance between fixation members. This dynamic adjustment capability enables precise control over the distraction rate and bone lengthening process, improving patient compliance by providing clear mechanical feedback while optimizing healing time through controlled progression.
Solution Approach 2:
The ratchet mechanism provides mechanical feedback during adjustment, allowing patients or clinicians to sense and control the distraction force and displacement. This feedback mechanism ensures proper compliance by providing tactile confirmation of correct operation and prevents over-compression or over-distraction, thereby optimizing bone healing time.
3Stability of the object's composition
If compression or distraction forces are applied to bone portions, then bone alignment is improved, but control and adjustability of the forces become challenging
Solution Approach 1:
The connection assembly features a dynamic ratchet mechanism that enables controlled adjustment of compression and distraction forces. The ratchet teeth and engagement mechanism provide discrete, controlled increments of force adjustment, making it easy to operate while maintaining precise control over bone alignment. The mechanism allows forces to be applied and adjusted without complex instrumentation.
Data Source
AI summary
An external fixation system includes a first elongate rod having a first ratchet end and a first fixation end; and a second elongate rod having a second ratchet end and a second fixation end. A ratchet assembly is attached to the first ratchet end and the second ratchet end. The ratchet assembly is configured to compress the first and second elongate rods to each other. A first fixation member is attached to the first fixation end and a second fixation member is attached to the second fixation end.