Modular Hoffa Fracture Plate Fixation Without AP Screw Interference
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Solution Overview
Problem
Existing methods for fixing Hoffa fractures, particularly in cases of multiple femur fractures, are limited by interference from anterior-posterior screws blocking plate fixation and the need for expanding fixation capabilities.
Innovation Solution
A fixation system comprising a main plate and an outrigger plate, with a coupling member, allowing selective orientation and deformation to stabilize the fracture, reducing the need for AP screws and enhancing fixation options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anterior-posterior bone screws are used to fix Hoffa fractures, then the condylar fragment can be secured to the distal femur, but the screws block plate fixation and limit fixation options when multiple fractures are present
Solution Approach 1:
The fixation system is divided into two separate components: a main plate for securing to the distal femur shaft and an outrigger plate for securing to the condylar fragment. This segmentation eliminates the need for anterior-posterior screws by providing separate attachment points, allowing each plate to perform its specific function without interfering with the other, thus maintaining fixation stability while expanding versatility for multiple fracture patterns
Solution Approach 2:
The outrigger plate extends perpendicular to the main plate, creating a three-dimensional fixation structure. This dimensional change allows the outrigger plate to reach the condylar fragment from a different spatial direction, avoiding the path of anterior-posterior screws and enabling plate fixation without screw interference
2Adaptability or versatility
If a single plate is used for fixation, then the device complexity is reduced, but the fixation footprint is limited and cannot adequately stabilize multiple fracture patterns
Solution Approach 1:
The outrigger plate is designed to be mounted onto the main plate, creating a nested configuration where one plate component attaches to another. This nesting approach expands the fixation footprint to address multiple fracture patterns while keeping the device complexity manageable through a modular, hierarchical structure rather than requiring completely separate fixation systems
Solution Approach 2:
The main plate serves multiple functions: it provides structural support for the distal femur shaft, serves as a mounting base for the outrigger plate, and can directly secure to bone when needed. The outrigger plate similarly provides both structural support for the condylar fragment and serves as an extension of the main plate's fixation capability, creating a multi-functional system that addresses various fracture patterns
3Reliability
If the outrigger plate is made longer and wider to increase stabilization, then the fixation capability is improved, but the plate interference with AP screws increases and the device becomes more complex
Solution Approach 1:
The outrigger plate is designed with non-uniform dimensions, being longer and wider only in the specific regions needed to reach and stabilize the condylar fragment, while remaining compact in other areas. This localized expansion provides adequate fracture stabilization without unnecessarily increasing overall plate size and complexity, allowing the plate to be precisely sized for its specific stabilization function
Data Source
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AI summary
System and method for fixing a distal femur having a Hoffa fracture. The system may comprise a main plate, an outrigger plate, and a coupling member that mounts the outrigger plate to the main plate. In an exemplary method, an elongated body portion of the main plate may be secured to a shaft region of the distal femur, and a wider head portion of the main plate may be secured to an end region of the distal femur. The outrigger plate may be mounted on the head portion of the main plate, and an arm of the outrigger plate may be fastened to a condylar fragment of the femur with one or more fasteners, such that the outrigger plate spans and stabilizes the Hoffa fracture.