Variable Angle Bone Plate Tapered Thread Design
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Solution Overview
Problem
Conventional bone plates with variable angle holes lack the ability to securely lock bone screws at a range of angular orientations, limiting their versatility and stability in bone fixation applications.
Innovation Solution
A bone plate design featuring internal surfaces with tapered threaded regions and recesses that allow bone screws to threadedly mate at various angles, combined with a concave second region for compression screw insertion, enabling secure locking and angular flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional locking screws are inserted along the central screw hole axis, then the threaded screw head can mate with the bone plate, but the angular orientation flexibility is limited
Solution Approach 1:
The fixation hole is designed with a variable angle threaded region that allows the bone anchor to be oriented at different angles (first and second orientations) while maintaining reliable threaded mating. The threaded region's geometry dynamically adapts to accommodate angular variations, enabling the bone plate to lockingly receive the bone screw at multiple angular orientations without compromising fixation reliability.
Solution Approach 2:
The internal surface geometry is changed by creating a tapered threaded region with specific angular parameters that differ from conventional cylindrical holes. This parameter change in the hole's geometry (tapered walls, variable radius) enables the threaded region to engage the bone anchor head at multiple angles, transforming the fixed angular constraint into a variable angle capability.
2Adaptability or versatility
If the fixation hole is designed for variable angle insertion, then angular flexibility is improved, but the structural complexity of the hole increases
Solution Approach 1:
The fixation hole is segmented into distinct functional regions: a first region with a tapered threaded region for variable angle locking screw insertion, and a second region with a different geometry for compression screw insertion. This segmentation allows each region to be optimized for its specific function while collectively providing both angular flexibility and structural integrity.
Solution Approach 2:
Different regions of the fixation hole are given different local qualities and geometries. The first region has a tapered threaded structure optimized for variable angle locking, while the second region has a geometry optimized for compression force application. This local differentiation enables the hole to provide multiple functions without requiring the entire structure to be complex.
3Adaptability or versatility
If a single fixation hole design is used for both locking and compression screws, then device simplicity is maintained, but functional versatility is reduced
Solution Approach 1:
The fixation hole is designed as a multi-functional structure that can accommodate both locking screws (with variable angle capability) and compression screws within the same hole. The first region handles locking screw insertion with angular flexibility, while the second region handles compression screw insertion, making the single fixation hole universal for both screw types and eliminating the need for separate hole designs.
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.