Modular Tibia Stem With Retractable Anchors for Implant Stability
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Solution Overview
Problem
Tibia stem components in total ankle arthroplasty face issues with pistoning or loosening due to limited bone engagement, leading to implant instability and migration over time.
Innovation Solution
The design incorporates retractable members in the tibia stem component that can be controllably extended outward from the longitudinal axis to engage the intramedullary canal's surrounding bone, enhancing anchoring and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tibia stem component uses a simple cylindrical design, then the device complexity is low, but the bone engagement is insufficient leading to implant loosening
Solution Approach 1:
The tibia stem component incorporates retractable members that can dynamically change from a retracted state during insertion to an extended state after implantation. This dynamic transformation allows the stem to adapt its geometry to engage with the intramedullary canal bone, improving anchoring and preventing loosening without requiring a complex fixed structure
Solution Approach 2:
The stem structure is segmented into multiple retractable members that can independently extend or retract. This segmentation allows different portions of the stem to engage with bone at different locations within the intramedullary canal, providing distributed anchoring while maintaining a relatively simple overall stem geometry when retracted
2Reliability
If the retractable members are extended outward to engage bone, then the anchoring is enhanced, but the device complexity increases
Solution Approach 1:
The retractable members are designed to be controllably movable, allowing the system to self-adjust its configuration. The mechanism can be actuated by standard surgical instruments during the procedure, enabling the stem to self-anchor without requiring additional complex external fixation devices or multi-step procedures
Solution Approach 2:
The stem component changes its geometric parameters by extending or retracting the retractable members. This parameter change transforms the stem from a simple cylindrical shape to a more complex anchored structure, allowing the same component to provide both ease of insertion and strong anchoring without requiring multiple different implant designs
3Adaptability or versatility
If the stem is made modular with adjustable angles, then the adaptability to patient anatomy is improved, but the device complexity increases
Solution Approach 1:
The modular joint between the tibia stem component and tibia tray component allows dynamic adjustment of the angle between these elements. This dynamic adjustability enables the prosthesis to adapt to varying patient anatomies and surgical requirements while maintaining a relatively simple modular connection mechanism that can be adjusted intraoperatively
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.