Polyaxial Bone Plate Holes for Flexible Screw Fixation
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Solution Overview
Problem
Existing bone plates are limited in screw placement options due to dedicated locking and non-locking holes, restricting flexibility and effectiveness in securing fractures, especially when different screw types are required based on bone quality and type.
Innovation Solution
The development of bone plates with polyaxial holes that allow for the reception of both locking and non-locking screws at various angles, utilizing lips with decreasing and increasing diameters and conical profiles to secure screws through elastic deformation and insert configurations, enabling flexible screw placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dedicated locking and non-locking holes are used in the bone plate, then screw placement is simplified and secure, but the flexibility and options for screw placement are limited
Solution Approach 1:
The hole in the bone plate is designed to serve multiple functions: it can receive both locking screws and compression screws, and can accommodate screws inserted at various angles (polyaxial). This is achieved through a universal hole design that eliminates the need for separate dedicated holes for different screw types, thereby providing surgical flexibility while maintaining ease of operation
Solution Approach 2:
The hole incorporates a polyaxial mechanism that allows dynamic adjustment of screw insertion angles. The hole geometry enables screws to be inserted at multiple orientations (e.g., 0 degrees, 15 degrees, 30 degrees relative to the plate axis), providing adaptability for different anatomical configurations while maintaining secure fixation
2Reliability
If threaded holes are used to facilitate screw placement along the axis, then locking screw security is improved, but the ability to place screws at various angles is restricted
Solution Approach 1:
The hole design incorporates localized threading only in specific regions where needed for locking screw security, while other regions maintain smooth walls to accommodate compression screws and allow polyaxial insertion. This localized differentiation of hole properties enables both secure locking and angular flexibility
Solution Approach 2:
The hole is segmented into different functional zones: threaded portions for locking screw engagement and non-threaded portions for compression screw reception and angular insertion. This segmentation allows each zone to optimize its specific function while contributing to the overall versatility of the hole
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides surgeons with enhanced options for securing bone plates to bones, allowing for more effective fracture fixation by accommodating different screw types and angles, thereby improving healing outcomes.
Implementation Method 1
utilizing lips with decreasing and increasing diameters and conical profiles to secure screws through elastic deformation
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A bone plate includes a bone-contacting surface, and a hole for receiving a screw, the hole having a plurality of spaced apart scalloped regions and screw-engaging members which are spaced apart about a central axis of the hole, wherein each screw-engaging member separates adjacent scalloped regions, wherein the hole includes an engagement region, the engagement region having a converging-diverging profile, wherein the screw-engaging members are plastically deformable to form an interference connection between the screw-engaging members and a screw head of the screw.