Bone Plate Compression Holes for Single-Screw Dynamic Locking
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Solution Overview
Problem
Conventional bone plate systems for fracture fixation lack efficiency in providing dynamic compression and locking functions with a single bone fixation member, often requiring dedicated screws and resulting in higher prominence and longer healing times.
Innovation Solution
The bone plate system incorporates compression holes with specific geometries that allow dynamic compression and locking engagement using a single locking bone fixation member with a threaded head, enabling translation perpendicular to the central axis when offset, and a guide sleeve for polyaxial insertion, allowing for both functions without a dedicated compression screw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional bone plate systems use dedicated compression screws and locking screws separately, then both dynamic compression and locking functions can be achieved, but the number of screws increases leading to higher prominence and longer healing times
Solution Approach 1:
The locking bone fixation member is designed to perform multiple functions: it provides both dynamic compression through its threaded head engaging the compression surface, and locking engagement through its external threads engaging the complimentary variable angle plate locking structure. This multi-functional design eliminates the need for separate dedicated compression screws and locking screws, directly resolving the technical contradiction by reducing the quantity of screws while maintaining both compression and locking capabilities.
Solution Approach 2:
The invention merges the functions of previously separate compression screws and locking screws into a single integrated locking bone fixation member. The head portion with threaded engagement and the shaft with external threads are combined in one component, allowing both compression and locking functions to be achieved through a single screw insertion, thereby reducing the total number of screws required.
2Quantity of substance
If a single locking bone fixation member is used for both compression and locking, then the number of screws is reduced, but the hole geometry must accommodate both functions simultaneously
Solution Approach 1:
The hole is segmented into distinct functional zones: a compression surface zone with a specific ramp geometry for dynamic compression, and a locking structure zone with internal threads for locking engagement. The compression surface is positioned at a specific orientation relative to the central axis, while the locking structure is positioned to engage the external threads of the fixation member. This segmentation allows the single hole to accommodate both functions without excessive complexity.
Solution Approach 2:
The hole geometry utilizes three-dimensional spatial arrangement to accommodate both compression and locking functions. The compression surface is oriented at an angle to the central axis, creating a ramp effect for compression, while the locking structure extends in a different spatial dimension to engage the external threads. This dimensional arrangement allows both functions to coexist within the same hole without requiring overly complex two-dimensional patterns.
3Ease of operation
If the bone fixation member axis is offset from the central hole axis, then dynamic compression translation is achieved, but precise alignment becomes more difficult
Solution Approach 1:
The guide sleeve is positioned and secured to the bone plate before insertion of the bone fixation member. The guide sleeve pre-defines the insertion trajectory and maintains the necessary offset between the fixation member axis and the central hole axis. This preliminary positioning action ensures that when the fixation member is inserted, it automatically achieves the correct offset for dynamic compression without requiring high-precision manual alignment during the insertion process.
Solution Approach 2:
The guide sleeve acts as an intermediary component that facilitates the offset alignment between the bone fixation member and the hole. Rather than requiring direct precision alignment between the fixation member and the hole, the guide sleeve mediates this relationship by providing a guided insertion path that automatically establishes the correct offset geometry for dynamic compression.
Data Source
AI summary
A bone fixation system includes a bone plate having an outer surface, an opposed bone-facing surface, and an interior surface that defines a hole extending from the outer surface to the bone-facing surface along a central hole axis. The interior surface further defines a compression surface. The system includes a bone fixation member having a shaft extending from a head along a central fixation member axis. The head has an exterior surface that defines a threaded head portion configured for variable angle locking with a complimentary variable angle plate locking structure. The compression surface and the threaded head portion are cooperatively configured to translate the bone plate in a direction substantially perpendicular to the central hole axis when the threaded head portion contacts the compression surface when the bone fixation member axis is offset from the central hole axis at an offset parameter as the head advances within the hole.