Mechanical testing methods for orthopaedic research : an introduction

Mechanical testing in a controlled laboratory setting is a vital part of orthopaedic research for investigating the structural-level performance or material-level properties of bones, joints, cartilage, soft tissues, and implants. The results can help researchers stay up to date on new findings, medical companies to develop more effective products, and university educators to instruct students on the practical relevance of classroom learning, so that there is a better understanding of orthopaedic conditions and injuries to optimize treatment. This article provides a brief and practical introduction to commonly used state-of-the-art methods, as well as some classic methods which are accurate, easy to use, and inexpensive, to measure different outcomes during in vitro mechanical testing. Planning a mechanical testing study, however, must be done before any experimentation by goal formation, timeline creation, literature review, and so on. Force or torque methods use mechanical testing machines and individual load cells. Displacement or rotation methods include electromagnetic tracking, extensometers or inclinometers, ultrasonic tracking, and videography. Surface strain or stress methods consist of acoustic emission, digital image correlation, fibre optic sensors, strain gauges, and thermography. Interface area or pressure methods encompass Fujifilm, piezoelectric sensors, staining dye, and Tekscan. Interface tribology methods involve the analysis of fretting corrosion friction and wear.