Bone Plate Polygonal Locking Holes With Thread Interruption
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Solution Overview
Problem
Conventional bone plate systems for internal fracture fixation lack effective mechanisms to enhance locking engagement and dynamic compression, particularly in variable-angle insertions, leading to potential loosening and poor alignment of bone screws.
Innovation Solution
The bone plate design incorporates a recess that circumferentially interrupts the thread form, providing enhanced deformation characteristics and additional space for screw head angulation, along with a polygonal locking hole configuration that includes columns and corners, allowing for improved locking engagement and dynamic compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bone plate systems are used, then the basic fixation function is provided, but the locking engagement is insufficient and screw loosening occurs
Solution Approach 1:
The locking hole is divided into multiple columns (first, second, and third columns) with distinct thread paths. This segmentation allows different portions of the screw head to engage with different columns, distributing the locking load and enhancing overall locking engagement reliability.
Solution Approach 2:
The recess is strategically positioned to interrupt threads in specific locations where they are most needed for engagement. This creates localized variations in thread continuity, providing enhanced deformation characteristics and locking engagement at critical stress points without unnecessarily complicating the entire hole geometry.
2Adaptability or versatility
If variable-angle locking screws are used, then angulated insertion is enabled, but the locking stability decreases
Solution Approach 1:
The polygonal hole configuration with multiple columns provides multiple engagement points that maintain stability even when the screw is inserted at variable angles. The recess strategically positioned to interrupt threads in specific locations provides enhanced deformation characteristics that maintain locking stability during angulated insertion.
Solution Approach 2:
The recess is positioned asymmetrically within the polygonal hole configuration, creating an optimized engagement pattern that maintains locking stability during variable-angle insertion. The asymmetric placement of the recess relative to the columns creates a deformation pattern that preserves locking integrity regardless of insertion angle.
3Productivity
If dynamic compression is implemented, then gap reduction is achieved, but the translation distance is limited
Solution Approach 1:
The recess extends in a direction that adds an additional dimension to the dynamic compression mechanism. This allows the bone plate to translate further along the compression path by utilizing the recess space, thereby increasing the translation distance while maintaining gap reduction efficiency.
Data Source
AI summary
A bone plate defines an interior surface that defines: a hole extending through the plate along an axis; plate threads configured for locking with a threaded head of a locking screw; first, second, and third columns sequentially located about the axis; a first corner extending tangentially from the second to the first column; and a second corner extending tangentially from the third to the first column. The first and second corners are substantially equidistantly spaced from the axis. The plate threads extend across the first, second, and third columns and the first and second corners. The interior surface defines a recess between the second and third columns and facing the first column. An apex of the recess is spaced further from the axis than are the first and second corners, such that the recess circumferentially interrupts at least a portion of at least one of the plate threads.