3D-Printed Knee Orthosis Hinge for Patient-Specific ICoR
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Solution Overview
Problem
Existing knee orthoses have limited adaptability to individual patient needs, as their hinges are often off-the-shelf products that do not accurately mimic the center of rotation of the biological knee, leading to potential strain on cruciate ligaments and inadequate support during bending and extension.
Innovation Solution
A hinge mechanism for a knee orthosis is designed using 3D printing, comprising a first and second part with incisions for coupling pieces and a cover plate, allowing for a customizable and compact assembly that mimics the Instant Center of Rotation (ICoR) of the biological knee, ensuring dynamic load distribution and reduced strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If off-the-shelf hinges are used in knee orthoses, then manufacturing cost is reduced and assembly is simplified, but adaptability to individual patient needs and accuracy in mimicking biological knee rotation are limited
Solution Approach 1:
The hinge mechanism incorporates adjustable parameters including the position of coupling pieces along the incisions, the angle of the incisions themselves, and the placement of openings for coupling points. These parameters can be customized for each patient based on their specific anatomical measurements and injury characteristics, allowing the hinge to accurately mimic that patient's biological knee rotation center while still using standardized manufacturing processes.
Solution Approach 2:
The hinge design allows for dynamic adjustment of the coupling piece positions relative to the incisions. This enables the orthosis to adapt to changes in patient condition over time, allowing modification of the hinge's mechanical properties to match the patient's healing progress or changing needs, thereby resolving the contradiction between standardized production and individualized treatment.
2Device complexity
If off-the-shelf hinges with pre-placed openings are used, then device complexity is reduced, but the ability to accurately position coupling points to prevent unwanted muscle use and ligament strain is limited
Solution Approach 1:
The hinge mechanism features locally optimized properties through customized incision angles and coupling piece positions that are specifically tailored to each patient's anatomy. The incisions are positioned and angled to guide coupling pieces to precise locations that accurately replicate the patient's instantaneous center of rotation, while the number and placement of openings are optimized locally to prevent unwanted movements that could strain ligaments, rather than using a uniform design throughout.
3Adaptability or versatility
If custom-made knee orthoses with customized hinges are produced using traditional methods, then adaptability to patient needs is improved, but manufacturing cost and production time increase significantly
Solution Approach 1:
The design utilizes parametric modeling where patient-specific anatomical measurements directly determine hinge parameters such as incision angles, coupling piece positions, and opening locations. These parameters can be quickly adjusted in digital models based on patient data, enabling rapid customization without requiring time-consuming traditional manufacturing processes. The standardized base design with adjustable parameters allows custom orthoses to be produced efficiently.
4Ease of repair
If multiple separate parts are used in hinge assembly, then ease of assembly and repair is improved, but device complexity and weight increase
Solution Approach 1:
The hinge mechanism integrates multiple functions into unified components. The incisions are cut directly into the hinge body as integral features rather than separate elements, and the coupling pieces are designed to be inserted and secured within these incisions, forming a compact assembly. This merging of functions reduces the total number of parts and simplifies the overall structure while maintaining ease of assembly through the modular coupling piece design that can be independently installed and adjusted.
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 solution provides a customizable, lightweight, and cost-effective knee orthosis that accurately supports knee movement, reducing strain on cruciate ligaments and improving wearing comfort by accurately mimicking the biological knee's center of rotation.
Implementation Method 1
accurately imitates the center of rotation behavior or Instant Center of Rotation (ICoR) of the biological knee
Data Source
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AI summary
The invention is related to the technical field of orthopedic devices, in particular knee orthoses for supporting a knee joint, and more specifically of an orthopedic device with a hinge, wherein the movement of the device can be limited by means of the hinge and where the hinge of the device is formed via 3D printing so that a knee orthosis can be made to measure for the patient and where a minimum of different parts is required for the assembly of the knee brace. The invention also includes a method for installing such hinge mechanisms and a knee orthosis provided with such hinge mechanisms.