Contoured Knee Extender Rods and Straps for Controlled Extension

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Solution Overview

Problem

Existing mechanical devices for knee extension in post-surgical or post-injury settings are complex, difficult to operate, cause pain, and reduce patient compliance, leading to limited recovery of knee motion range.

Innovation Solution

A knee extender device with contoured extension rods and adjustable straps or eyelets, allowing controlled knee extension through tension application, providing comfort and flexibility for various configurations and sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex mechanical devices are used for knee extension, then knee extension function is achieved, but device complexity and difficulty of operation increase

Engineering Contradiction:

Improveknee extension functionVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The device is divided into multiple independent components: a rigid support structure, flexible straps for positioning, and a cord/belt mechanism for applying extension force. This segmentation allows each component to perform its specific function independently, simplifying the overall system while maintaining effective knee extension capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A cord or belt acts as an intermediary element that transmits force from the user's foot (wrapped around it) to the knee extender device. This intermediary mechanism allows the user to control the extension force through their own body weight and movement, reducing the need for complex motorized or mechanically complex systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If mechanical knee extension devices are used, then knee extension is achieved, but patient pain increases

Engineering Contradiction:

Improveknee extension functionVSAvoidpatient pain

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Flexible straps are used to wrap around the thigh and lower leg, providing a soft interface between the rigid extender device and the patient's body. These flexible elements distribute pressure evenly and prevent concentrated stress points, reducing pain while maintaining secure positioning for effective knee extension.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If complex mechanical devices are used for knee extension, then extension function is provided, but ease of operation decreases

Engineering Contradiction:

Improveknee extension functionVSAvoidease of operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The device is designed to be operated by the patient themselves using their own body mechanics. The patient wraps the strap around their foot and uses their own leg movement to tension the cord, which in turn drives the knee extension. This self-service mechanism eliminates the need for external power sources or complex control systems, making the device easy to operate while maintaining reliable extension function.

Inventive Principle:

Principle #25Self-service

4Force

If rigid structures are used for knee extension, then extension force is effective, but patient comfort decreases

Engineering Contradiction:

Improveextension forceVSAvoidpatient discomfort

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The device combines rigid support rods or bars that provide structural integrity and effective extension force with flexible straps that contact the patient's skin. The flexible straps conform to the patient's anatomy and distribute pressure, while the rigid components maintain the necessary mechanical strength to deliver effective knee extension force.

Inventive Principle:

Principle #30Flexible shells and thin films

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

Facilitates controlled and less painful knee extension, enhancing patient compliance and range of motion recovery by promoting terminal extension.

Implementation Method 1

as the individual subsequently pulls on the two ends of the cord or belt, the knee extender device is pushed downward due to the tension being applied to the cord or belt

Methodology Applied

Scientific EffectTension: Tension

Implementation Method 2

the force applied to the convex curvature of the curved upper surface... causes the device to extend the knee of the individual in a controlled manner

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentUS20250213415A1Knee extender devices and related methods

Publication Date: 2025.07.03 MARSHALL UNIVERSITY RESEARCH CORP

AI summary

A knee extender device includes a pair of contoured extension rods, with each extension rod including a central connecting portion, a first support leg and a second support leg extending downwardly from the central connecting portion and at an angle. A first terminal portion extends from the first support leg and a second terminal portion extends from the second support leg. A first strap connects the first terminal portions, a second strap connects the second terminal portions, and a third strap connects the central connecting portions. In use, the device is applied to a leg of the individual adjacent to and over the knee joint, and a cord or belt is extended around a foot of the individual. Upon applying tension to the cord or belt, the knee extender device is then pushed downward to thereby extend the knee of the individual.