Introduction

This document details requirements for a set of mechanical test methods to evaluate material used as a cortical bone model. Bone models have long been used in mechanical tests for devices or instruments such as those used in the orthopaedic surgery. The characteristics of the bone model, especially those of a cortical bone model, strongly influence the test results. Many devices and instruments are evaluated using bone models.

Newer bone models are needed because conventional bone model properties change the primary outcome of interest such as failure mode. This results in devices not being evaluated correctly. Animal bones such as those from pigs are still used. However, animal bones have many sanitary problems and can introduce large errors (standard deviation). Recently, several new bone models have been introduced and standardized methods for evaluating these materials are required.

This document introduces applicable standardized mechanical test methods for characterizing the material properties of cortical bone models. The mechanical properties of the cortical bone itself such as tensile strength and compressive strength have been measured for some time, and several models have been produced based on the results. However, these fundamental mechanical properties do not strictly conform to the tactile feedback experienced by physicians. Material models have differences in tensile, compressive and shear strengths properties since they do not reproduce the complex anisotropic bone structure. For example, a material can be an excellent bone model based on tensile strength, but have significant differences in compressive and shear strengths. Therefore, the model needs to be specific for the application to match the material properties as needed. This is because many kinds of fundamental properties are related in practical uses. Then, it is also necessary to perform practical tests of the bone model using devices and to show relationships of mechanical characteristics between from fundamental tests and from practical tests.

This document shows the relations and covers test methods for fundamental and practical tests. The final goal of this document is to facilitate the availability of good medical devices and instruments to patients. The mechanical properties under practical tests can also be useful to produce models of training and lectures of new devices, informed consent for patients and performances of pre-operation or surgical planning.

BS ISO 19213:2017

Implants for surgery. Test methods of material for use as a cortical bone model

Current, Under Review

Published:

31 Jul 2017