Session: 10-07-01: Problem Solving Techniques in Engineering and Technology Education, Research Methodologies, Practice, Workshops and Seminars

Paper Number: 165057

Application of TRIZ as a Problem Solving Technique in Arthroplasty 

INTRODUCTION

TRIZ (Theory of Inventive Problem Solving) was developed after studying approximately 400,000 patents. This systematic method processes conflicting conditions during design problem-solving and can be applied to various issues, including prosthetic design challenges. It is used to develop specific solutions to non-specific problems. It does so by converting a non-specific problem to a simplified one and then to a general one, and specific solutions are derived from those general solutions. This study presents and showcases TRIZ as a potential design solution generator for the hip and knee arthroplasty design challenges by offering some potential general and specific solutions utilizing the TRIZ methodology. The framework is explained, and potential solutions are drawn using a few contradictions. This showcases the method's efficacy in generating innovative solution findings and optimizing design with specific focus on orthopaedic arthroplasty.

 

METHODS

An explanted Stryker Trident Ceramic-on-Ceramic (CoC) hip bearing, removed secondary to squeaking (due to femoral head articulation on the ceramic acetabulum shell) was modeled using TRIZ methodology. Engineering and physical constraints were identified, and potential general solutions were found using 39 design parameters.  The visual examination of the ceramic femoral revealed grey marks on the femoral head of the implant, showing material transfer of titanium alloy onto the alumina head, which was made the basis of the analysis.

In the initial stages of problem-solving with TRIZ, each relevant system component is identified and its interaction with other components is defined. The interactions between the components of a CoC hip system and the super system of bone/acetabulum were developed in a matrix format with a diagonal symmetry. Components with no interactions were removed. In addition, a functional model of the system was developed to identify functional relationships between the components, which were shown to interact as per the interaction matrix. Harmful actions were identified as generating ceramic wear particles due to articulation, generating metal debris due to the impingement of the femoral neck and the metallic shell, and micromotion at the taper junction of the neck and the head. Finally, the engineering constraints were further converted into physical constraints, and potential solutions were determined utilizing the inventive principles. They were examined for resolving by space, time, condition/relation, direction, and system-level separation.

A functional model for knee arthroplasty focusing on knee liner wear and cracking is also presented.

 

RESULTS

The potential solutions offered by the inventive principles included use of composite materials, and using dissimilar materials for the head and cup; or, using Porous materials, recommending making an object porous or adding porous elements (inserts, coatings, etc.). Potential solution based on the above inventive principles: adding graphene to the ceramic may enhance wear and friction properties. In addition, it is accepted and known that changing the liner to HDPE from Ceramic will also alleviate the squeaking issue.

Modifying the Local quality recommends changing an object's structure from uniform to non-uniform and changing an external environment (or external influence) from uniform to non-uniform. Another recommendation asks for moving an object in two – or three–dimensional space or using 'another side' of a given area. Based upon these inventive principles, it is concluded that the design should have discontinuous surfaces. In addition, lubrication injection and/or removal of wear debris particles should be incorporated if ceramic articulating surfaces are preserved.

DISCUSSION

The TRIZ methodology is applied to squeaking CoC Hip Arthroplasty, and a functional model for knee arthroplasty is also offered. The framework is explained, and potential solutions are drawn using a few contradictions. This showcases the method's utility and relevance in generating innovative solution findings and optimizing design.

Presenting Author: Manish Paliwal The College of New Jersey

Presenting Author Biography: Mechanical Engineer, Professor, Professional Engineer (Registered in Maryland)

Authors:

Manish Paliwal The College of New Jersey