Revolvable Extension Plate for Periprosthetic Fracture Fixation
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Solution Overview
Problem
Existing attachment devices for bone plates used in treating periprosthetic fractures require separate fixation elements and alignment processes, which can be cumbersome and may intrude into the medullary canal, posing challenges in achieving stable fixation without penetrating the canal.
Innovation Solution
A fixation system comprising an elongate plate with offset attachment portions and a revolvable extension plate, allowing for alignment and attachment without separate fixation elements, ensuring screws do not penetrate the medullary canal by rotating the extension plate to position fasteners appropriately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an attachment device with receiving holes is used to align fixation elements, then the alignment precision is improved, but the device complexity increases due to requiring separate fixation elements and alignment processes
Solution Approach 1:
The patent combines the alignment function and fixation function into a single integrated attachment device. The offset attachment portions with apertures serve both to align the device with the medullary canal and to receive fixation elements simultaneously, eliminating the need for separate alignment tools and receiving holes.
Solution Approach 2:
The patent extracts the alignment function from the fixation structure by positioning apertures at offset locations that naturally align with the medullary canal during insertion. This separates the alignment requirement from the fixation mechanism, allowing the fixation elements to be directly received in the offset apertures without additional alignment features.
2Stability of the object's composition
If fixation elements are inserted through the attachment device to secure it to the bone plate, then the stability is improved, but the risk of intruding into the medullary canal increases
Solution Approach 1:
The patent employs asymmetric positioning of attachment portions relative to the device's central axis. The offset apertures are positioned at specific distances from the centerline, creating an asymmetric configuration that directs fixation elements away from the medullary canal while maintaining stable attachment to the bone plate.
Solution Approach 2:
The patent transitions from a one-dimensional linear alignment approach to a two-dimensional offset positioning system. By positioning apertures in both longitudinal and transverse dimensions relative to the device axis, the fixation elements are directed into a safe zone that avoids the medullary canal while achieving stable fixation.
3Reliability
If the attachment device is fixed to the long bone plate with a fixation element, then the reliability is improved, but the ease of operation deteriorates due to requiring separate fixation elements and alignment processes
Solution Approach 1:
The patent incorporates preliminary alignment features in the form of offset apertures that are pre-positioned to align with the medullary canal during device insertion. This preliminary alignment action is built into the device structure itself, eliminating the need for separate alignment steps and fixation elements, thereby improving ease of operation while maintaining reliability.
Data Source
AI summary
A fixation system includes an elongate plate and an extension plate. The elongate plate includes an inner wall and has a longitudinal axis. The extension plate has first and second attachment portions offset from one another. An engagement portion extends outwardly from the first attachment portion. The engagement portion is couplable to the inner wall of the elongate plate. The second attachment portion defines an aperture for receiving a fastener. The second attachment portion is revolvable about the longitudinal axis of the inner wall when the engagement portion is coupled to and movable about the inner wall. A fastener is received into the first attachment portion to attach the extension plate to the elongate plate. Another fastener is received into the second attachment portion and into a bone part.