External Fixation System with Cam Mechanism for Bone Adjustment
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Solution Overview
Problem
Existing external fixation devices for bone stabilization are cumbersome and difficult to adjust incrementally, leading to potential improper adjustments and discomfort for patients, particularly when used by non-physician caregivers.
Innovation Solution
The external fixation system incorporates ring assemblies with linear and angular distractors, selectively engageable fasteners, and clamps, featuring adjustable mechanisms with tactile and visual feedback to facilitate precise and reliable incremental adjustments, allowing for distraction, reduction, and compression of bone segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional fasteners (hex nuts and threaded bolts) are used for adjustment, then the distraction device can be assembled and adjusted, but the adjustment process becomes awkward, slow, and difficult to perform incrementally and reliably
Solution Approach 1:
The patent replaces the conventional threaded bolt and hex nut mechanical system with a cam mechanism. The cam's curved surface profile allows for incremental angular rotations that translate to precise linear adjustments of the distraction device, eliminating the need for threading operations and enabling faster, more reliable adjustments by non-physician caregivers.
2Reliability
If conventional fasteners are used, then the components can be secured, but the complexity of the system leads to improper adjustments, non-compliance, and undue discomfort for patients
Solution Approach 1:
The cam mechanism replaces complex threaded fasteners with a simpler rotational cam that engages with a flat surface on the elongated member. This substitution reduces the number of components and assembly steps, lowering system complexity while improving reliability through tactile and audible feedback during adjustment.
Solution Approach 2:
The cam mechanism incorporates tactile feedback through its curved surface profile and audible feedback through clicking sounds during engagement. This feedback system guides non-physician caregivers through proper incremental adjustments, ensuring compliance with treatment protocols and reducing improper adjustments.
3Strength
If hex nuts and threaded bolts are used, then secure attachment is achieved, but the adjustment process is awkward and difficult for non-physician caregivers to perform
Solution Approach 1:
The cam mechanism maintains secure attachment through the mechanical engagement between the cam's curved surface and the flat surface on the elongated member. The cam's design provides sufficient holding strength while enabling easy rotational adjustment by non-physician caregivers, eliminating the need for threading operations.
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 system enables simple, reliable, and precise adjustments, reducing the risk of improper use and enhancing patient comfort by providing clear visual and tactile cues for operators, thus improving the efficacy of bone stabilization and healing processes.
Implementation Method 1
The knob may have a detent mechanism which may engage one or more indentations positioned around the body portion. Such a construction may provide tactile and/or audible indications to an operator of incremental movements of the distractor
Implementation Method 2
Rotation of the knob may cause the elongated member to move relative to the knob and within the body portion
Data Source
AI summary
An external fixation system for connecting one or more bone segments together to facilitate healing of bone. The system may include one or more rings and/or ring segments. One or more linear distractors and/or angular distractors may connect the rings to each other so as to allow for distraction and/or reduction/compression of a bone. Linear distractors may enable an operator to move the rings towards and away from each other, while angular distractors may enable an operator to angle the rings relative to each other. In an embodiment using angular distractors, one or more angular separation assemblies may be positioned between the rings. These separation assemblies may have joints which may two portions which may be angled relative to each other and connected directly or indirectly to the rings. Various fasteners (e.g., nuts) and/or tightening members may configured for quick movement along and selective tightening to various components. Moreover, clamps may be attached to the rings and may engage pins, wire, rods, which may be inserted into bone to hold bone segments to each other. The components of the external fixation system may be provided in sets or kits so that the a surgeon may select various combinations of components to create an external fixation system which is configured specifically for the particular needs of a patient and the bone fracture/deformity.