Retractable Tibia Stem Anchoring for Ankle Prosthesis Stability
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Solution Overview
Problem
Current tibia stem components in total ankle arthroplasty face challenges with pistoning or loosening due to limited bone engagement, leading to long-term complications such as implant migration and instability.
Innovation Solution
The development of a tibia stem component with retractable members that can be controllably extended to engage the intramedullary canal's surrounding bone, enhancing anchoring within the canal, and a modular design allowing adjustable angle configurations between the tibia stem and tray components for improved stability and fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional tibia stem component is used, then the device structure is simple, but the implant stability is insufficient and pistoning or loosening occurs
Solution Approach 1:
The tibia stem component incorporates retractable members that can dynamically change their configuration from retracted to extended positions. This dynamic feature allows the stem to adapt to different surgical needs and bone conditions, providing enhanced anchoring when required while maintaining a compact form when not in use, thereby resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The tibia stem is divided into multiple segments including the main stem body and separate retractable members. This segmentation allows each component to perform its specific function independently - the main stem provides structural support while the retractable members provide enhanced anchoring when extended, thus improving implant stability without requiring the entire device to be complex.
2Reliability
If the retractable members are extended outward, then the anchoring of the tibia stem is enhanced, but the device complexity increases
Solution Approach 1:
The retractable members are nested within the main stem body when in the retracted position, similar to a nested doll structure. This nesting approach allows the complex anchoring mechanism to be compact and integrated within the simple outer structure of the stem, providing enhanced anchoring capability without significantly increasing the overall device complexity or size.
3Adaptability or versatility
If a fixed-angle tibia stem design is used, then the manufacturing is simple, but the adaptability to anatomical variations is limited
Solution Approach 1:
The modular design with adjustable angle components allows the tibia stem system to dynamically adapt to different anatomical configurations. The ability to adjust the angle between the stem and tray components provides versatility for accommodating anatomical variations while maintaining relatively simple manufacturing processes for each individual module.
Solution Approach 2:
The tibia stem system is segmented into modular components that can be independently manufactured and then assembled at different angles. This segmentation enables each component to be manufactured using standard processes while the final assembly provides the adaptability needed for different anatomical variations, resolving the contradiction between ease of manufacture and adaptability.
Data Source
AI summary
Provided are tibia stem components of ankle replacement prosthesis that are designed to engage dense tibia bone to reduce implant migration over long term.