Multi-piece Ankle Prosthesis Stem for Minimally Invasive Fixation
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Solution Overview
Problem
Current ankle replacement systems face issues with subsidence and aseptic loosening, and traditional surgical methods are invasive, leading to limited mobility and increased stress on adjacent joints.
Innovation Solution
A multi-piece stem component and articulating artificial joint surfaces with ball-and-socket or saddle-shaped designs that allow for rotation and translation, along with minimally invasive intramedullary guidance and snap-fit assembly, to reduce subsidence and improve mobility while minimizing surgical trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ankle replacement systems are used, then the ankle joint can move, but subsidence and aseptic loosening occur frequently
Solution Approach 1:
The stem component is divided into multiple segments that can be assembled in situ through a small surgical opening. This segmentation allows for better adaptation to the bone structure, improved fixation stability, and reduced occurrence of subsidence and aseptic loosening while maintaining manageable device complexity during surgery.
2Reliability
If minimally invasive surgical method is used, then healing is improved and failure rate decreases, but installation of large components through small opening becomes difficult
Solution Approach 1:
The stem component is segmented into multiple smaller parts that can be sequentially inserted through a small surgical opening and assembled in situ. This resolves the contradiction by enabling minimally invasive surgery while still installing the necessary large-scale structural components.
Solution Approach 2:
The multi-piece stem components are designed to nest within each other or connect sequentially through the small surgical opening, allowing large overall structure installation through minimal incision while maintaining ease of operation.
3Stability of the object's composition
If ankle fusion procedure is used, then joint stability is achieved, but ankle mobility is lost and stress on knee and hip joints increases
Solution Approach 1:
The prosthesis design maintains dynamic mobility of the ankle joint through articulating surfaces that allow natural motion, while the multi-piece stem provides static stability through secure bone fixation. This resolves the contradiction by providing both stability and mobility simultaneously.
Data Source
AI summary
A prosthesis suited for orthopedic implantation possesses a multi-piece stem component that supports an artificial joint surface that can articulate with another artificial joint surface in various ways. The prosthesis can be assembled in a snap fit and/or interlocking fashion that provides positive locking means without the use of screws or other fasteners. The prosthesis can accommodate fitment of a plastic joint surface made, e.g., from ultra high molecular weight polyethylene. The prosthesis is well suited for use in an ankle replacement system that can be installed using minimally invasive intramedullary guidance established with respect to the major axis of the tibia by minimally invasive access through the calcaneus, through an incision in the bottom of the foot. The prosthesis makes possible the installation of a total ankle system using minimally invasive anterior access to the ankle joint for making bony cuts and to install prosthesis components.