Prosthetic Ankle Interlocking Mechanism
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Solution Overview
Problem
Current prosthetic ankle components face challenges such as dislodgment of mobile bearing inserts during use, stringent regulatory approval processes, and limited surgical access due to the small working area in ankle replacement surgeries, which complicates accurate placement and increases costs.
Innovation Solution
A prosthetic ankle assembly featuring a first and second prosthetic ankle component with interlocking protrusions and receiving portions that allow sliding and limited rotation, preventing dislodgment and facilitating easier assembly, while maintaining the benefits of a mobile bearing insert, and incorporating a lip for resilient locking and improved surgical access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an unconstrained mobile bearing insert is used, then articulation is improved due to additional degrees of freedom, but the insert may become dislodged during use
Solution Approach 1:
The bearing insert is segmented with protrusions that can move independently within receiving portions, allowing articulation while preventing complete dislodgment. The insert is divided into functional zones: articulating surfaces for movement and protrusion-receiving interfaces for retention.
Solution Approach 2:
The protrusions on the bearing insert are nested within receiving portions on the implant components. This nested configuration allows the insert to move freely for articulation while the receiving portions act as retaining structures that prevent dislodgment, creating a hierarchical retention system.
2Manufacturing precision
If a fixed insert is used, then placement accuracy is maintained, but accurate placement is difficult and time consuming to achieve
Solution Approach 1:
The bearing insert performs self-alignment through its protrusions fitting into receiving portions, automatically positioning itself correctly during insertion. This self-service mechanism eliminates the need for complex alignment procedures by the surgeon, reducing surgical time while maintaining placement accuracy.
Solution Approach 2:
The receiving portions are pre-configured with specific geometries that guide the protrusions into correct positions before final insertion. This preliminary configuration of the retention features ensures proper alignment is achieved automatically, reducing the time and skill required for accurate placement.
3Device complexity
If a fixed insert is used, then regulatory approval is simpler, but the insert requires accurate placement that is costly to correct
Solution Approach 1:
The bearing insert transitions from a completely fixed design to a dynamically constrained design where protrusions can move within receiving portions. This dynamic configuration allows regulated movement for safety while maintaining ease of insertion and correction, balancing regulatory requirements with surgical flexibility.
4Area of stationary object
If the ankle presents a smaller access area, then surgical access is limited, but accurate placement becomes more difficult
Solution Approach 1:
The self-aligning protrusion-receiving portion mechanism allows the bearing insert to automatically position itself accurately within the limited surgical access area. This eliminates the need for complex alignment maneuvers that would be difficult to perform through the restricted ankle access, maintaining placement accuracy despite limited working space.
Data Source
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AI summary
A first prosthetic ankle component (10) comprising: a first bearing surface (12) configured to engage a second bearing surface (22) of a second prosthetic ankle component (20); and a protrusion (16) or slot (26) on the first bearing surface, the protrusion or slot being configured to engage a respective slot (26) or protrusion (16) in the second bearing surface of the second prosthetic ankle component, wherein the protrusion or slot is further configured such that the interaction with the respective slot or protrusion permits the first and second prosthetic ankle components to slide with respect to one another in an interface plane defined by the interface between the first and second bearing surfaces, and wherein the protrusion or slot is further configured to restrict the first and second prosthetic ankle components moving away from one another in a direction with a component perpendicular to the interface plane.