Variable-Angle Bone Plate With Threaded Holes
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Solution Overview
Problem
Conventional bone plate systems face issues with screw loosening due to dynamic loading, limited ability to compress bone fragments, and cumbersome manipulation during surgery, particularly when using polyaxial systems with multiple components.
Innovation Solution
A versatile bone plate system with holes that accommodate non-locking, locking, and variable-angle locking screws, featuring discrete columns of teeth or thread segments for secure engagement, allowing screws to be inserted at various angles without the need for bushings or expandable rings, and enabling long-term fixation with improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If locking screws are used to secure the plate, then resistance to shear forces is improved, but the ability to compress bone fragments is reduced
Solution Approach 1:
The bone plate system is designed to accommodate both locking and non-locking screws in the same plate, allowing each screw type to be used in specific holes depending on the surgical requirements. The plate holes are configured with thread segments that can engage with either locking or non-locking screws, providing multi-functionality. This enables the surgeon to use locking screws where shear resistance is critical and non-locking screws where bone compression is needed, resolving the contradiction between these two opposing requirements.
2Force
If non-locking screws are used to compress bone fragments, then compression ability is improved, but resistance to shear forces is reduced leading to screw loosening
Solution Approach 1:
The bone plate is designed with the capability to receive both locking and non-locking screws, allowing the surgeon to select the appropriate screw type for each specific hole based on whether compression or shear resistance is the primary requirement. This universal design eliminates the need to choose between the two screw types for the entire plate, allowing optimal performance in both compression and shear resistance simultaneously across different locations.
3Adaptability or versatility
If polyaxial systems with multiple components are used to allow variable angle insertion, then adaptability is improved, but device complexity and ease of operation are worsened
Solution Approach 1:
The patent removes the bushing component from the polyaxial system, allowing screws to be inserted at variable angles directly through the plate holes without requiring an intermediate bushing element. The plate holes are configured with thread segments that engage the screws at various angles, eliminating the need for separate bushings and simplifying the overall device structure while maintaining adaptability for variable angle insertion.
Solution Approach 2:
The bone plate is designed to accommodate both locking and non-locking screws at variable angles without requiring different plate designs or additional components. The same plate configuration can receive either screw type at various angles, providing universal functionality that reduces device complexity while maintaining versatility.
4Adaptability or versatility
If bushings or expandable rings are used in polyaxial systems to lock screws at desired angles, then variable angle locking is achieved, but ease of operation is worsened due to cumbersome manipulation
Solution Approach 1:
The patent eliminates the bushing component entirely, allowing screws to be inserted at variable angles directly into the plate holes. The thread segments in the plate holes engage the screw threads directly, providing variable angle locking without requiring the insertion and manipulation of separate bushing components. This simplifies the surgical procedure and improves ease of operation.
Data Source
Figure 1~2
Figure 3A
Figure 3B~3C
AI summary
A bone plate system for internal fixation of bone fractures includes a bone plate having a plurality of bone plate holes. The holes are constructed to receive either a non-locking, locking, or variable angle locking bone screw. The holes have discrete columns of thread segments arranged around the inner surface of the hole for engaging threads on the heads of locking and variable angle locking bone screws. Conventional locking bone screws engage the bone plate coaxially with the central axis of the bone plate hole. Variable angle locking bone screws can engage the bone plate at a selectable angle within a range of angles relative to the bone plate. The head of the variable angle locking screw is at least partially spherical, and the thread thereon has a profile that follows the arc-shaped radius of curvature of the spherical portion of the screw head.