Dynamic Bone Fracture Plate With Spring Ratchet Compression
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Solution Overview
Problem
Conventional bone plates used for stabilizing fractures have a high modulus of elasticity, limiting their ability to apply controlled compressive forces necessary for bone healing, and often shift the stress burden from the bone to the plate, impairing the healing process.
Innovation Solution
A dynamic bone fracture plate assembly featuring a female and male plate portion connected by a spring mechanism with ratchet teeth and pawls, allowing for linear movement and adjustable compressive force application, enabling controlled compression and stabilization of bone fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rigid metal bone plates are used for fracture stabilization, then mechanical strength and stability are improved, but the ability to apply controlled compressive force is limited and stress is shifted from bone to plate
Solution Approach 1:
The bone plate system transitions from a static rigid structure to a dynamic system with movable components. The distal plate segment can move relative to the proximal plate segment along the longitudinal axis, allowing the plate to dynamically adjust and maintain controlled compressive force across the fracture site while preserving mechanical strength.
Solution Approach 2:
The system changes the mechanical parameter of stiffness by introducing a movable joint between plate segments. This allows the plate to transition between rigid and compliant states, enabling controlled compression while maintaining overall structural integrity and strength.
2Device complexity
If conventional static bone plates are used, then structural simplicity is maintained, but the ability to promote rapid healing through controlled compression is lost
Solution Approach 1:
The introduction of a dynamic compression mechanism with movable plate segments and spring element adds controlled complexity to the device structure, enabling it to actively promote healing through sustained compression while maintaining reasonable structural simplicity.
Solution Approach 2:
The spring element automatically maintains compressive force across the fracture site without requiring external intervention. The system self-regulates the compression force, allowing the device to actively promote healing while keeping the overall structure relatively simple.
3Ease of manufacture
If rigid metal plates with high modulus of elasticity are used, then ease of manufacture is improved, but the ability to distribute stress appropriately to the bone is reduced
Solution Approach 1:
The bone plate is divided into multiple segments (proximal and distal plates) connected by a movable joint. This segmentation allows each segment to move independently, enabling appropriate stress distribution to the bone while maintaining manufacturing simplicity for each individual segment.
Solution Approach 2:
The system changes the effective modulus of elasticity by introducing a compliant joint between rigid plate segments. This allows the overall structure to distribute stress appropriately to the bone while each individual segment remains manufacturable using conventional processes.
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
The dynamic bone plate assembly applies a controlled compressive load to facilitate bone healing by distributing stress appropriately, promoting rapid fracture stabilization and recovery.
Implementation Method 1
A spring dynamically connects the plate portions to one another such that the spring maintains a compressive load across the fracture
Implementation Method 2
The arm has a plurality of ratchet teeth grouped together... and a pawl for engaging the ratchet teeth
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A bone fracture plate assembly including female and male plate portions. The female plate portion has a post, a female dovetail, and an extending arm with a group of ratchet teeth. The male plate portion has two upstanding posts, a male dovetail for coupling to the female dovetail so that the plate portions move linearly with respect to each other, a slot for the arm, and a pawl for engaging the ratchet teeth. A spring, coupled to the posts of the plate portions, dynamically connects the plate portions by applying a compressive load therebetween. The spring has a pair of elongated ears, each defining a slot to allow for relative movement of the plate portions. The ratchet teeth are engaged by the pawl to retain the plate portions together, and the spring mounts on the posts of the plate portions such that the spring biases the plate portions together.