ASTM_F_3141_-_17a.pdf

Designation:F314117aStandard Guide forTotal Knee Replacement Loading Profiles1This standard is issued under the fixed designation F3141;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 Motion path,load history and loading modalities allcontribute to the wear,degradation and damage of implantedprosthetics.Simulating a variety of functional activities prom-ises more realistic testing for wear and damage mode evalua-tion.Such activities are often called activities of daily living(ADLs).ADLs identified in the literature include walking,stairascent and decent,sit-to-stand,stand-to-sit,squatting,kneeling,cross-legged sitting,into bath,out of bath,turningand cutting motions(1-7).2Activities other than walking gaitoften involve an extended range of motion and higher imposedloading conditions which have the ability to cause damage andmodes of failure other than normal wear(8-10).1.2 This document provides guidance for functional simu-lation that could be used to evaluate in vitro the durability ofknee prosthetic devices under force control.1.3 Function simulation is defined as the reproduction ofloads and motions that might be encountered in activities ofdaily living but it does not necessarily cover every possibletype of loading.Functional simulation differs from typicalwear testing in that it attempts to exercise the prosthetic devicethrough a variety of loading and motion conditions such asmight be encountered in situ in the human body in order toreveal various damage modes and damage mechanisms thatmight be encountered throughout the life of the prostheticdevice.1.4 Force control is defined as the mode of control of thetest machine that accepts a force level as the set point input andwhich utilizes a force feedback signal in a control loop toachieve that set point input.For knee simulation,the flexionmotion is placed under angular displacement control,internaland external rotation is placed under torque control,and axialload,anterior posterior shear and medial lateral shear areplaced under force control.1.5 This document establishes kinetic and kinematic testconditions for several activities of daily living,includingwalking,turning navigational movements,stair climbing,stairdescent,and squatting.The kinetic and kinematic test condi-tions are expressed as reference waveforms used to drive therelevant simulator machine actuators.These waveforms repre-sent motion,as in the case of flexion extension,or kineticsignals representing the forces and moments resulting frombody dynamics,gravitation and the active musculature actingacross the knee.1.6 This document does not address the assessment ormeasurement of damage modes,or wear or failure of theprosthetic device.1.7 This document is a guide.As defined by ASTM in their“Form and Style for ASTM Standards”book in section C15.2,“A standard guide is a compendium of information or series ofoptions that does not recommend a specific course of action.Guides are intended to increase the awareness of informationand approaches in a given subject area.Guides may propose aseries of options or instructions that offer direction withoutrecommending a definite course of action.The purpose of thistype of standard is to offer guidance based on a consensus ofviewpoints but not to establish a standard practice to follow inall cases.”The intent of this guide is to provide loading profilesand test procedures to develop testing that might be used forwear,durability or other types of testing of total knee replace-ments.As noted in this definition,a guide provides guidance ontesting,but does not require specific testing.Thus,for example,if a user is unable to control one mode of force control givenin the load profiles,that user is not required to perform thatmode of loading.1.8 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.1This guide is under the jurisdiction of ASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved Dec.1,2017.Published January 2018.Originallyapproved in 2015.Last previous edition approved in 2017 as F314117.DOI:10.1520/F3141-17A.2The boldface numbers in parentheses re