Extra-articular Spring Load Transfer for Knee Osteoarthritis

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Solution Overview

Problem

Current joint replacement and osteotomy procedures for osteoarthritis are invasive and result in long recovery times, lack of chondro-protection, and inability to control joint load, leading to further damage and pain due to imbalanced loading on the joint.

Innovation Solution

A load transferring system comprising two bases coupled to bones defining a joint and a spring that exerts a tensile force between the bases during flexion, transferring load from the lateral compartment of the knee joint to the medial compartment to balance loads and alleviate pain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If joint replacement or osteotomy procedures are performed to treat osteoarthritis, then pain relief and joint function are improved, but the procedures are highly invasive and require substantial recovery periods

Engineering Contradiction:
Improvepain relief and joint functionVSAvoidrecovery period
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent introduces an extra-articular implantable mechanical energy absorbing system as an intermediary device that spans the tibiofemoral joint and is anchored into the tibia and femur. This mediator absorbs mechanical energy and reduces loads on the articular surfaces without requiring replacement of the joint surfaces themselves, thereby avoiding the invasiveness and long recovery associated with traditional joint replacement procedures

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If traditional arthroplasty procedures are performed, then joint surfaces are replaced or realigned, but chondrocytes are removed or left to contend with new joint anatomy and injury, resulting in no chondro-protection

Engineering Contradiction:
Improvejoint surface functionVSAvoidchondrocyte damage and loss of cartilage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The energy absorbing system acts as a protective intermediary that reduces mechanical loads on the articular surfaces and chondrocytes. By absorbing excess energy and reducing peak loads, the device protects cartilage and chondrocytes from further injury while allowing the joint to maintain its natural anatomy and physiology

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The device provides beforehand cushioning by being implanted prior to potential further cartilage damage. It continuously absorbs mechanical energy and reduces loads on the articular surfaces, protecting chondrocytes from future injury and creating a more favorable environment for cartilage preservation and potential regeneration

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Shape

If osteotomy procedures are performed to improve joint alignment, then mechanical alignment is corrected, but ligamentous instability is not addressed and results deteriorate over time

Engineering Contradiction:
Improvejoint alignmentVSAvoidlong-term stability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent combines mechanical alignment correction through osteotomy with ligamentous stabilization through the extra-articular implantable energy absorbing system. The device addresses both mechanical alignment and ligamentous instability simultaneously, providing comprehensive treatment that prevents the deterioration seen with osteotomy alone

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If load transferring system with spring is implanted, then load is transferred from lateral to medial compartment reducing pain, but device complexity increases

Engineering Contradiction:
Improvepain reduction and load balancingVSAvoidimplant structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the load transfer function from the joint itself and places it in an extra-articular energy absorbing system. By taking the load management function out of the joint, the device simplifies the overall system while providing effective load transfer from the lateral to medial compartment, reducing pain without requiring complex intra-articular modifications

Inventive Principle:
Principle #2Taking out (Extraction)

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

The system effectively reduces pain and load on the lateral compartment, enhances joint function, and supports natural motion by transferring load from the lateral to the medial compartment during flexion, potentially promoting cartilage regeneration and reducing osteoarthritis progression.

Implementation Method 1

a spring configured to couple to the bases. The spring may be configured to exert a tensile force between the bases during flexion of the joint

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2854713B1Load transferring systems for transferring load in a joint
Publication Date: 2019.01.16 MOXIMED INC
  • EP2854713B1 patent drawingFigure 1
  • EP2854713B1 patent drawingFigure 2
  • EP2854713B1 patent drawingFigure 3

AI summary

Load transferring systems and related methods for transferring load in a joint are provided. The load transferring system may include two bases configured to couple to bones defining a joint and a spring configured to couple to the bases. The spring may be configured to exert a tensile force between the bases during flexion of the joint. The load transferring system may be employed to treat symptoms associated with osteoarthritis of the lateral compartment of the knee joint. Thus, the bases may respectively couple to the femur and tibia. The spring may exert tensile force therebetween during flexion of the knee joint so as to unload the lateral compartment of the knee joint by transferring load from the lateral compartment of the knee joint to the medial compartment of the knee joint.