Load-Adaptive Porous Structure for Bone Ingrowth and Strength
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Solution Overview
Problem
Existing medical devices with porous structures face challenges in balancing low stiffness for normal loads with high mechanical strength for exceptional loads, which can lead to compromised bone remodeling and ingrowth, and increased risk of osteosynthesis and stress shielding.
Innovation Solution
A medical device with a porous structure that varies its configuration based on applied loads, transitioning from a low stiffness state to a high stiffness state, achieved through a design with disengaging and engaging surface portions and elastic connection members, allowing for enhanced bone ingrowth and stability under normal loads while providing mechanical strength during exceptional loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the beams of the porous structure are thickened to withstand exceptional loads, then the mechanical strength is improved, but the stiffness increases which jeopardizes bone remodelling and ingrowth
Solution Approach 1:
The porous structure is designed to dynamically change its configuration in response to applied loads. Under normal physiological loads, the structure maintains a first configuration with lower stiffness to promote bone ingrowth. When subjected to exceptional or accidental loads, it transitions to a second configuration with higher stiffness and mechanical strength to withstand the increased stress without compromising bone remodelling under normal conditions.
Solution Approach 2:
The patent employs parameter changes by designing the porous structure with load-dependent mechanical properties. The structure's stiffness and configuration are not fixed but change based on the magnitude of applied load. This allows the same structure to provide appropriate mechanical support across different loading scenarios - maintaining low stiffness for bone ingrowth during normal use, and providing high strength protection during exceptional events.
2Stability of the object's composition
If the porous structure maintains low stiffness to promote bone ingrowth, then bone remodelling is enhanced, but the device cannot withstand exceptional or accidental loads
Solution Approach 1:
The porous structure utilizes dynamic configuration changes to adapt its mechanical properties based on loading conditions. During normal physiological loading, the structure maintains a configuration optimized for bone ingrowth with appropriate flexibility. Upon detecting exceptional loads through the applied stress, the structure transitions to a more rigid configuration that can safely withstand the abnormal forces, thereby ensuring reliability without compromising bone integration during normal operation.
3Strength
If the porous structure is strengthened to provide greater support, then the mechanical strength is improved, but the risk of osteosynthesis and stress shielding increases
Solution Approach 1:
The dynamic configuration capability allows the porous structure to modulate its stiffness in response to applied loads. Under normal physiological conditions, the structure maintains lower stiffness that matches natural bone mechanics, allowing stress to be transmitted to the surrounding bone tissue to prevent stress shielding and promote osteosynthesis. Only during exceptional loading events does the structure transition to a higher stiffness state, minimizing the risk of stress shielding during normal operation while providing necessary support during abnormal events.
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 device maintains low stiffness under normal loads to promote bone ingrowth and stability, while achieving high mechanical strength during exceptional loads, reducing the risk of osteosynthesis and stress shielding, thereby enhancing long-term implant stability.
Implementation Method 1
a configuration of the porous structure varies in dependence on a load applied to the porous structure, such that the porous structure has a first configuration when the load is of a first magnitude, and has a second configuration when the load is of a second magnitude greater than the first magnitude
Data Source
AI summary
Disclosed is a medical device comprising a porous structure, wherein a configuration of the porous structure varies in dependence on a load applied to the porous structure, such that the porous structure has a first configuration when the load is of a first magnitude, and has a second configuration when the load is of a second magnitude greater than the first magnitude. The porous structure comprises a first surface portion and a second surface portion. The first surface portion is disengaged from the second surface portion when the porous structure has the first configuration, and is engaged with the second surface portion when the porous structure has the second configuration.