Orthopedic Plate Locking Compression Slot for Variable-Angle Screws
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Solution Overview
Problem
Existing orthopedic plates with compression capabilities are limited by fixed screw angles and complex, expensive constructions that restrict the ability to provide sufficient compressive force.
Innovation Solution
An orthopedic plate with a slot design that allows screws to be inserted at angles between perpendicular and 15 degrees, featuring angled ramps that cause the plate to traverse and lock, providing angular stability and compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-angle compression housing is used, then the screw insertion angle is constrained, but the compression force application is limited
Solution Approach 1:
The slot is designed with angled surfaces that allow the plate to dynamically adjust its position relative to the screw during insertion. The slot transitions from a fixed geometry to a dynamic system where the plate can traverse along the slot's length, enabling variable insertion angles while maintaining compression force application.
Solution Approach 2:
The compression mechanism is segmented into distinct functional zones within the slot: an initial insertion region, a compression region with angled surfaces, and a locking region. This segmentation allows each zone to perform its specific function independently, enabling angle variability without requiring a completely redesigned housing structure.
2Force
If multi-segment bone plates with springs are used, then compression capability is provided, but the construction becomes complex and expensive
Solution Approach 1:
The spring mechanism is extracted and replaced with a direct mechanical compression system using the slot's angled surfaces. Instead of using elastic elements (springs) to provide compression, the design uses the geometric configuration of the slot and plate interaction to generate and transmit compressive forces directly, eliminating the need for complex spring assemblies.
Solution Approach 2:
The plate itself serves the dual function of both the structural component and the compression mechanism. By designing the slot with specific angular geometries, the plate utilizes its own structural features to generate compression force during screw insertion, rather than requiring separate compression components or springs.
3Force
If springs are used to provide compressive force, then compression is achieved, but the force is limited to the tensile force of the springs
Solution Approach 1:
The design changes the fundamental parameter of force generation from elastic deformation (spring tensile force) to geometric mechanical advantage. By utilizing the angled surfaces of the slot and the plate's traversal along the slot, the system can generate compression forces greater than what would be limited by spring tensile strength, as the force is derived from the mechanical interaction and geometry rather than material elasticity.
Data Source
AI summary
Assemblies and methods for fixation of bone or bone fragments using an orthopedic plate having a slot that causes the bone or bone fragments to compress as a screw is inserted into the slot and rotated therein. By anchoring the orthopedic plate to a first bone or bone fragment and rotating the screw into the second bone or bone fragment at an angle that may be up to approximately fifteen degrees from perpendicular to the top surface of the orthopedic plate, the screw head causes the orthopedic plate to traverse away from the first screw thereby causing the first bone or bone fragment to be drawn toward and/or compress with the second bone or bone fragment.