External Fixation Strut Acute Adjustment Mechanism
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Solution Overview
Problem
Current orthopedic external fixation devices, such as hexapod systems, face challenges in providing precise and efficient adjustment mechanisms for securing bone fragments, particularly in achieving acute adjustments and preventing accidental changes during patient use.
Innovation Solution
The external fixation strut incorporates an acute adjustment mechanism with a mobile jaw and disengagement member, allowing for precise adjustment while preventing accidental changes through a band that covers the disengagement member, ensuring safety and efficiency in strut length adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an acute adjustment mechanism is added to enable gross adjustments, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The acute adjustment mechanism is nested within the existing strut body, with the mobile jaw and disengagement member integrated into the longitudinal axis of the strut. This allows the acute adjustment functionality to be incorporated without significantly increasing the overall device footprint or complexity.
Solution Approach 2:
The mobile jaw acts as an intermediary component that translates rotational movement of the disengagement member into longitudinal movement of the threaded rod. This mediator mechanism enables acute adjustments without requiring direct manual manipulation of the threaded rod itself.
2Reliability
If a band is added to cover the disengagement member and prevent accidental adjustments, then the reliability is improved, but the ease of operation deteriorates
Solution Approach 1:
The band is pre-applied to cover the disengagement member before the patient begins using the device. This preliminary protective action prevents accidental adjustments without requiring the patient to perform any additional steps during normal operation.
Solution Approach 2:
The protective function is extracted as a separate component (the band) that can be independently applied and removed. This allows the safety feature to be added without permanently modifying the adjustment mechanism itself, maintaining ease of operation when the band is intentionally removed.
3Reliability
If the mobile jaw is biased to engage with the threaded rod, then the reliability is improved, but the ease of operation worsens due to requiring force to disengage
Solution Approach 1:
The spring bias creating engagement force is counterbalanced by the lever action of the disengagement member. When the disengagement member is rotated, it creates a counteracting force that overcomes the spring bias, allowing controlled disengagement without requiring excessive force from the user.
Solution Approach 2:
The system transitions from a static engagement state (spring-loaded mobile jaw holding the threaded rod) to a dynamic disengagement process (rotational movement of disengagement member). This dynamic approach allows the engagement force to be maintained during normal use while enabling easy release when needed.
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
This design facilitates gross and acute adjustments, enhances safety by preventing accidental adjustments, and preserves the working length of the threaded rod, improving the overall efficiency and usability of the external fixation system.
Implementation Method 1
the threaded rod may translate relative to the strut body to change the overall length of the strut
Implementation Method 2
a mobile jaw that is engageable with the threads of the threaded rod
Implementation Method 3
a disengagement member configured to interact with the mobile jaw to disengage the mobile jaw from the threads of the threaded rod
Data Source
AI summary
Embodiments of the invention include an external fixation system that includes at least one external fixation strut that is both acutely adjustable and precisely adjustable and related methods of adjustment. Acute adjustment may be accomplished using one or more mobile jaws that may be engaged with or disengage from a threaded rod of each external fixation strut. Precise adjustment of each external fixation strut may be accomplished after releasing a lock biased toward a locked position. When each external fixation strut's lock is released, a portion of each of the precise adjustment mechanism of each external fixation strut may be activated to increase and decrease the length of each of the at least one external fixation struts.