Bone Fixation Guide Sleeve Resists Rotational Misalignment
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Solution Overview
Problem
Current bone fracture fixation methods using bone nails or screws are insufficient to counteract rotational forces, leading to potential misalignment and failure of fracture healing due to screw loosening and crossing of fixation means.
Innovation Solution
A device comprising a securing plate and guide sleeves that allow controlled movement of bone fragments while securing bone screws to prevent rotational forces from causing misalignment, with the screws being locked to the plate to maintain stability and compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixation means (bone screws/nails) are used to fix bone fragments, then bone fragments are secured, but rotational forces cause the fixation means to rotate and cross one another, leading to misalignment and failure of fracture healing
Solution Approach 1:
The device allows dynamic compression of bone fragments through the guide sleeve mechanism while preventing rotational movement of the fixation means. The guide sleeve permits linear movement for compression but constrains angular rotation, enabling the system to adapt to compression forces while maintaining fixed angular positions of the fixation means relative to the securing plate.
Solution Approach 2:
The guide sleeve acts as an intermediary element between the fixation means and the securing plate. It mediates the interaction by allowing controlled compression movement while preventing rotational displacement, thus protecting the fixation means from crossing one another while still permitting necessary bone fragment compression.
2Stability of the object's composition
If fixation means are locked to securing plate to prevent rotation, then angular position is maintained, but compression of bone fragments is restricted
Solution Approach 1:
The guide sleeve creates a dynamic connection that permits linear compression movement while preventing rotational movement. This dynamic mechanism allows the system to simultaneously maintain angular stability and enable compression, resolving the contradiction between fixing the angular position and allowing compression operation.
Solution Approach 2:
The device segments the movement degrees of freedom by allowing compression movement along the axis of the fixation means while preventing rotational movement around that axis. The guide sleeve effectively separates these two motion components, permitting one while constraining the other.
3Reliability
If multiple fixation means are used to counteract rotational forces, then stability is improved, but the risk of screws loosening and crossing increases
Solution Approach 1:
The guide sleeve serves as a protective intermediary that prevents the harmful interaction between multiple fixation means. By constraining their angular positions relative to the securing plate, it eliminates the crossing hazard while still allowing them to work together to resist rotational forces on the bone fragments.
Solution Approach 2:
The guide sleeve applies preliminary constraint to prevent the potential harmful action of screw rotation and crossing before it can occur. By pre-establishing the angular relationship between fixation means and the securing plate, it prevents the loosening and crossing that would otherwise happen under rotational loading.
Data Source
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AI summary
The present invention relates to a device for fixation of bone fragments at bone fractures. The device comprises at least two fixation means (5, 6) and a securing plate (4). With the object of preventing or counteracting re-dislocation, the respective fixation means (5, 6) each have a first fixing portion (19) for fixing the fixation means in an inner bone fragment (3), a second fixing portion (21 ) for locking the fixation means to the securing plate (4) which is disposed on the outside of an outer bone fragment (2) and allows movement of the outer bone fragment relative to it, so that the fixation means are prevented from changing their angular position relative to the securing plate and relative to one another, and a middle portion (22) which is situated between the fixing portions and runs through the outer bone fragment, along which middle portion the outer bone fragment can slide inwards towards the inner bone fragment in which the fixation means is fixed.