Integrated Knee Prosthesis Extensor Mechanism for Buckling Resistance
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Solution Overview
Problem
Conventional knee replacements require a functional extensor system, which is absent in some patients, leading to the need for amputation or joint fusion, resulting in reduced quality of life and high disability.
Innovation Solution
An implantable total knee prosthesis with an integrated prosthetic extensor mechanism, including a biasing mechanism and brake mechanism, simulating normal knee function by providing adjustable force and resistance to compensate for non-functional extensor systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional knee replacement is performed, then the knee joint can be replaced, but the procedure requires a functional extensor system which is absent in some patients
Solution Approach 1:
The patent introduces a prosthetic extensor mechanism as an intermediary component between the knee joint prosthesis and the patient's compromised extensor system. This mechanism includes a femoral component with a quadriceps tendon and patellar ligament that mediates the force transmission from the quadriceps muscle to the tibia, enabling knee extension function even when the native extensor system is non-functional.
Solution Approach 2:
The prosthetic extensor mechanism is designed to be self-contained and self-functional, with the femoral component containing all necessary elements (quadriceps tendon, patellar ligament, patella) to provide extensor function independently. The mechanism serves itself by creating its own extensor apparatus rather than relying on the patient's compromised native extensor system.
2Reliability
If amputation above the knee is performed, then the non-functional extensor system is removed, but the patient experiences high level of dysfunction and disability
Solution Approach 1:
The patent extracts only the non-functional soft tissue extensor system while preserving the bone structure and inserting a prosthetic extensor mechanism. Rather than removing the entire leg (amputation), the procedure extracts only the compromised extensor components and replaces them with a prosthetic mechanism that restores function.
Solution Approach 2:
The patent changes the physical parameters of the extensor system by replacing biological soft tissue with a prosthetic mechanism that has different material properties but achieves the same functional outcome. The prosthetic components are designed with specific geometric parameters (tendon thickness, ligament tension, patella size) to replicate normal extensor function.
3Stability of the object's composition
If total fusion of the knee joint is performed, then joint stability is achieved, but the patient loses knee mobility and flexibility
Solution Approach 1:
The patent implements a dynamic knee joint prosthesis with a prosthetic extensor mechanism that allows controlled flexion and extension movements. The mechanism includes movable components (patella, tendons, ligaments) that dynamically adapt during the gait cycle, providing stability when needed and mobility when required, rather than fixed fusion.
Solution Approach 2:
The patent segments the knee joint into distinct functional components: the prosthetic joint for rotation, the femoral component with extensor mechanism for extension control, and the tibial component for weight bearing. This segmentation allows independent optimization of each component's function while maintaining overall joint stability and mobility.
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
Enables individuals with compromised extensor systems to walk and climb stairs without fear of knee buckling, avoiding amputation or joint fusion, and improving mobility.
Implementation Method 1
a biasing mechanism configured to apply elastic force to the prosthetic extensor mechanism
Implementation Method 2
a brake mechanism configured to apply friction force to at least one rotating component
Data Source
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AI summary
An implantable knee prosthesis comprising a femoral stem component, a tibial stem component and a hinged joint having at least one hinge pivot point and an axis of limited rotation, the implantable knee prosthesis having a prosthetic extensor system configured to simulate a level of natural movement for patients with compromised extensor systems.