Variable Angle Bone Plate Segmented Thread Design
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Solution Overview
Problem
Conventional bone plates with variable angle holes lack sufficient angulation and surface area contact with bone screws, leading to unreliable fixation and increased risk of screw misalignment during bone repair procedures.
Innovation Solution
A bone plate design featuring internal surfaces with threaded regions and recesses that divide threads into columns, allowing screws to be inserted at various angles and providing increased surface area contact with the screw head, enhancing the reliability of the threaded purchase between the bone plate and bone anchor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional variable angle holes are used in bone plates, then the plate structure remains simple, but the angulation range and surface area contact with bone screws are insufficient
Solution Approach 1:
The internal surface of the fixation hole is segmented into multiple recesses that divide the threaded region into columns. This segmentation allows the bone plate to accommodate screws at various angles by providing multiple threaded surfaces oriented at different angles, thereby increasing the angulation range without requiring multiple separate fixation holes.
Solution Approach 2:
The invention transitions from a conventional single-axis threaded hole to a multi-dimensional threaded structure with recesses extending in multiple directions. The threaded region is configured to engage with bone screws inserted at different trajectories, adding angular dimensionality to the fixation capability while maintaining a single hole location.
2Reliability
If conventional variable angle holes are used, then manufacturing remains simple, but the surface area contact with bone screws is limited leading to unreliable fixation
Solution Approach 1:
The threaded region is divided into multiple columns by recesses, creating multiple engagement surfaces for bone screw threads. This increases the total surface area contact between the bone plate and bone screw, distributing the fixation load across multiple interfaces and thereby improving fixation reliability.
Solution Approach 2:
Multiple threaded surfaces at different angles are merged into a single integrated fixation hole structure. The recesses and threaded regions are combined to form a unified component that provides both angular versatility and enhanced surface area contact, improving reliability without requiring multiple separate fixation elements.
3Manufacturing precision
If conventional variable angle holes are used, then the design remains simple, but screw misalignment risk increases during bone repair procedures
Solution Approach 1:
Different regions of the internal surface are given different local qualities through the recesses and threaded columns. Each threaded column is oriented at specific angles to guide and accommodate bone screws inserted at corresponding trajectories, providing localized engagement surfaces that ensure proper screw alignment and reduce misalignment risk.
Data Source
AI summary
A bone plate having at least one variable angle locking hole is described. The variable angle locking hole allows a bone anchor having a threaded head to be driven into underlying bone while oriented at an angle with respect to a central hole axis of the hole that is within a range of angles at which the head is configured to threadedly mate with the at least one thread of the bone plate. Accordingly, the bone anchor can be driven into the underlying bone until the threaded head threadedly purchases with the bone plate inside the variable angle locking hole.