Bone Plate Screw Trajectories for Pull-Out and Collapse Resistance
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Solution Overview
Problem
Current bone plate and screw designs fail to provide optimal screw purchase and stability in bones with poor quality, such as the proximal humerus, leading to less-than-ideal healing due to screw pull-out and bone collapse.
Innovation Solution
A bone plate design featuring multiple sets of screw holes allowing screws to be placed in convergence, parallel, and calcar trajectories, with varying angles and orientations to enhance screw resistance and prevent bone collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard parallel screw trajectories are used, then the bone plate can be easily manufactured and installed, but the screw resistance to pull-out is insufficient and bone collapse occurs in poor quality bones
Solution Approach 1:
The bone plate is segmented into multiple groups of screw holes (first group with converging trajectories, second group with parallel trajectories, third group with diverging trajectories). This segmentation allows different regions of the plate to provide different mechanical functions, with the converging and diverging trajectories specifically designed to increase screw resistance to pull-out in poor quality bones.
Solution Approach 2:
Different regions of the bone plate are designed with locally optimized screw hole trajectories. The first group of holes provides converging trajectories for enhanced pull-out resistance in the proximal region, the second group provides parallel trajectories for standard fixation, and the third group provides diverging trajectories for distal fixation. This local quality variation allows the plate to adapt to varying bone quality along its length.
2Stability of the object's composition
If multiple screw trajectories are implemented, then bone collapse resistance is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The bone plate is pre-manufactured with precisely engineered screw hole trajectories (converging, parallel, and diverging) that are designed to prevent bone collapse before implantation occurs. The converging trajectories of the first group of holes and the diverging trajectories of the third group are specifically configured to distribute mechanical loads and prevent bone collapse during the healing process.
Solution Approach 2:
The screw hole trajectories exhibit asymmetric configurations relative to the bone plate's central axis. The first group of holes has converging trajectories that asymmetricaly distribute forces, while the third group has diverging trajectories that also asymmetricaly counteract collapse forces. This asymmetry is deliberately designed to optimize resistance to bone collapse in specific directional loads.
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
The present application relates to apparatus and methods for securing a bone fracture using a bone plate with at least four pairs of screws layered in convergent, standard (divergent), convergent, and calcar trajectories. The orientation of the screw trajectories in the plate reduces the relative motion of the bone along the screws, increasing resistance to pull-out of screws and to bone collapse.