Bone Plate Depression Design for Stress Peak Reduction
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Solution Overview
Problem
Bone plates with variable-angle through holes experience stress peaks when subjected to bending loads, particularly in the regions with recesses near the side edges, which can lead to breakage.
Innovation Solution
A bone plate design featuring a depression on the non-bone-facing surface that overlaps with the through hole, reducing stress peaks by distributing load more evenly and minimizing sharp edges, combined with a rib-like structure within the through hole for variable-angle screw locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable-angle through holes with recesses are provided in the bone plate, then adaptability for different screw angles is improved, but stress peaks occur in the region of recesses under bending load
Solution Approach 1:
The patent applies local quality by providing recesses only in specific regions of the variable-angle through hole where screw locking is needed, while maintaining intact rib-like structures in other regions to bear bending loads. This localized modification allows the bone plate to have different structural properties in different areas: flexible angle adjustment where needed and high strength where loads are applied.
Solution Approach 2:
The rib-like structure in the through hole is segmented into multiple regions: some segments are interrupted to form recesses for variable-angle screw locking, while other segments remain intact to provide structural support. This segmentation allows the structure to simultaneously achieve angle variability and load-bearing capacity.
2Strength
If material is removed to create depressions or recesses for stress reduction, then stress peaks are reduced, but the bone plate structure becomes more complex
Solution Approach 1:
Instead of uniformly simplifying the entire bone plate structure, the patent applies local quality by creating depressions and recesses only in specific high-stress regions. This targeted material removal reduces stress peaks without unnecessarily complicating the overall structure, maintaining simplicity in low-stress areas.
Data Source
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AI summary
A bone plate having a first, bone-facing surface and an opposing second surface has an elongate shaft portion and a head portion that is shorter and wider in comparison thereto, with at least one through hole extending through the bone plate from the first surface to the second surface in the shaft portion. The through hole comprises a variable-angle portion with a hole axis configured to receive a threaded head of a locking screw therein at a desired angle within a permitted range of angulation relative to the hole axis. The second surface has at least one depression which extends therein along a portion of the second surface between the side wall and the through hole, the depression extending about a periphery of the through hole.