1、Designation: F3141 15Standard 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 parent
2、heses 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 fun
3、ctional 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,
4、 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
5、 functional simu-lation to evaluate the durability of knee prosthetic devicesunder 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. Function
6、al 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 throughou
7、t 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 und
8、er 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, inc
9、ludingwalking, 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, o
10、r 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
11、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 are
12、a. 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 thi
13、s 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 us
14、er 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 esta
15、blish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E74 Practice of Calibration of Force-Measuring Instruments1This guide is under the jurisdiction of ASTM Committee F04 on Medical andSurgic
16、al Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved Dec. 15, 2015. Published February 2016. DOI:10.1520/F314115.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM st
17、andards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
18、 PA 19428-2959. United States1for Verifying the Force Indication of Testing MachinesE2309 Practices for Verification of Displacement MeasuringSystems and Devices Used in Material Testing MachinesE2624 Practice for Torque Calibration of Testing Machines3. Reference Frame System (see Fig. 1)3.1 Two ri
19、ght-handed coordinate systems are defined asreference frames; one with an origin at OTfixed to the tibia anda second with an origin at OFfixed to the femur.3.2 Displacements (rotations and translations) shall meandisplacements of the tibial component relative to the femoralcomponent. The anatomical
20、axes correspond to the mechanicalaxes described by Grood and Suntay (11). Table 1 shows themechanical axes and abbreviations corresponding to eachanatomical axis.3.3 The orientation and location of the axes of the referenceframes follow the approach defined by Pennock (12). However,to accommodate th
21、e simulator machine (versus anatomical)setting several modifications are made to the Pennockapproach, as described in 3.4.3.4 The femoral reference frame defines three coordinateaxes, XF,YF, and ZFall coincident at the origin OF. The flexionaxis, XF, shall be defined as collinear with a line passing
22、through the coordinates of the average center of curvature ofthe posterior 90 degrees of condylar arc. The average center ofcurvature shall be developed individually for the medial andlateral condyles based on regular increments of angle from 0 to90 degrees of posterior arc (the transepicondylar lin
23、e may besubstituted for the average center of curvature if the manufac-turer specifies that reference frame for surgical alignmentpurposes). The long axis of the femur, ZF, lies on a line passingthrough the center of the femoral head which extends to themedial lateral midpoint of the trans-condylar
24、line, lying on theXFaxis, connecting the most medial and most lateral points ofthe medial and lateral femoral condyles at their most distalTwo righted-handed reference frames, OFand OT, are embedded in and move with the femur and tibia respectively. The coordinate system and signs are based on arigh
25、t knee and forces and moments are considered to be applied to the tibia shaft with reaction forces acting at the joint articular surface.FIG. 1 Reference Frame SystemTABLE 1 Anatomical Meaning of Coordinate System Axes andAbbreviationsAnatomical Axis Coordinate Axis AbbreviationsMedial Lateral XFMLA
26、nterior Posterior YTAPAxial ZTAXFlexion Extension XFFEInternal External Rotation ZTIEAbduction Adduction YFAAF3141 152projection. The ZFaxis shall be perpendicular to the XFaxisand the YFaxis shall be defined as the cross product of the ZFand XFaxes.3.5 The tibial reference frame defines three coord
27、inate axes,XT,YT, and ZT, all coincident at the origin OT. The anatomicallong axis of the tibia, ZT, is defined by a line extending fromthe center of the tibial intercondylar eminence to the center ofthe ankle (12). This definition shall be adopted for thisstandard. The XT,YT, axis shall be defined
28、with the knee in fullextension and in a neutral configuration. In that configurationthe XTaxis shall be parallel to the femoral XFaxis and the YTaxis will be coplanar with the plane of the YFand ZFaxes. TheXTand YTaxes will be mutually perpendicular to the ZTaxis.The origin OTof the tibial coordinat
29、e system shall be locatedsuch that the XTaxis is tangent to the most distal aspect of thetibial articular bearing surface.3.6 Grood and Suntay describe the motions of the kneeusing the notion of a mechanical linkage that constrainsrotation and translation axes in a way that is thought to beclinicall
30、y relevant. To define this motion a floating axis, YFisutilized. This axis is labeled the abduction axis. The abductionaxis remains perpendicular to both the XFaxis and the ZTaxisin all configurations. The abduction axis is rotated about the XFaxis by an arc equal to flexion-extension arc.4. Termino
31、logy4.1 Definitions:4.1.1 activity model, nan activity model provides a kine-matic and kinetic description of a particular physiologicalactivity. Each activity model shall provide a set of time seriesdata that represents one cycle of the subject activity. The timeseries data provided by an activity
32、model are used as inputs tocontrol the motions and forces of the test machine. The timeseries data required to characterize each activity are: (1) axialforce, (2) flexion-extension angle, (3) axial tibial torque, (4)anterior-posterior force, and (5) medial-lateral force. Thesetorques or forces may r
33、esult in the motion of the femur or tibialrelative to the other. How these motions are described may bemachine-dependent, as to whether it is a motion of the tibiarelative to the femur or the femur relative to the tibia. Thefollowing descriptions are frequently described as motion ofthe tibia, but c
34、ould also be described as motion of the femur.4.1.2 activities of daily living, ADLs, nthese are thephysiological activities to which a human knee may be subjectduring the course of normal living. TypicalADLs include: highfrequency maneuvers such as walking and turning; naviga-tional maneuvers such
35、as cross over turning and pivot turning;deep knee flexion maneuvers such as squatting, stair ascent anddescent; high loading maneuvers such as stumbling; andathletic activities.4.1.3 AP translation, dTapor dTymm, ntranslation of thetibial component along the YTaxis (anterior posterior axis); apositi
36、ve displacement moves the tibia in the anterior direction.The magnitude of the displacement is expressed relative to thereference position.4.1.4 AP force, fTapor fTyN, napplied anterior orposterior force acting on the tibial component parallel to the YTaxis. A positive AP force acts in the positive
37、YTdirection andwill result in an anterior translation of the tibia.4.1.5 applied force, napplied force is that force acting onthe joint originating from external sources (includes the mus-culature). When magnitude and direction are specified theapplied force shall be considered to be acting on the t
38、ibial shaftwith balancing reaction forces at the joint surface.4.1.5.1 DiscussionThe forces acting across the knee arepartitioned into applied and constraint forces while the con-straint forces are further partitioned into joint reaction forceand soft tissue constraint force. The applied force is co
39、mprisedof the sum of the influences of gravitation, body dynamics, andthe action of the active musculature. The joint reaction force iscomprised of the influence of all of the mechanisms whichcontribute to the forces of contact acting on the articular jointsurface. The soft tissue constraint force i
40、s comprised of the sumof all of the influences of the passive soft tissue structure whichis dominated by the elastic and viscoelastic response of theligaments and capsular structure surrounding the joint.4.1.6 joint coordinate system, JCS, nthe coordinate sys-tem and kinematic chain described by Gro
41、od and Suntay torepresent the translational and rotational axes and motions ofthe knee.4.1.7 neutral position, nthis is the position where theforces (or torques) are zero and corresponds to zero on theforce (or torque) deflection graphs defining the constraintforces and torques.4.1.8 reference orien
42、tation, nthe reference orientation isthe relative alignment of the tibial and femoral componentsdefined by the manufacturer as the desirable alignment at fullextension and neutral IE rotation.4.1.9 reference position, nthe reference position is deter-mined with the prosthetic components aligned in t
43、he referenceorientation. The reference position is that position on the APand ML axis where an axial load results in no AP or MLreaction force. This may be determined experimentally in thetest machine by applying 100 N of axial load and thenexercising the machine through a range of AP or ML motionwh
44、ile recording the correspondingAPor MLreaction force anddisplacement. The midpoint of the minimum cusp of the forcedisplacement curve is the reference position.4.1.9.1 DiscussionThe reference position may be deter-mined analytically or graphically as that point where, when inthe reference orientatio
45、n, the surface normal of contact pointsof the femoral and tibial components are collinear with theaxial load axis.5. Significance and Use5.1 The purpose of this test guide is to provide informationon how to test a total knee replacement in order to evaluate itsfunction during several types of knee m
46、otions.5.2 This test guide may help characterize the magnitude andlocation of implant wear as an implant is repetitively movedaccording to specified load and displacement waveforms.5.3 This test guide may also help characterize the functionallimitations of a total knee replacement as its motion is g
47、uidedF3141 153by these waveforms. These limitations may be observed asimpingement, subluxation or high loading in the soft tissueconstraints, whether they are represented physically or virtu-ally.5.4 The motions and load conditions in vivo will, in general,differ from the load and motions defined in
48、 this guide. Theresults obtained from this guide cannot be used to directlypredict in vivo performance. However, this guide is designed toallow for comparisons in performance of different kneedesigns, when tested under similar conditions.6. Apparatus6.1 A joint motion simulator machine is required f
49、or thistesting.6.2 Suggested cyclic frequency specified for each activity isgiven in Table 2. The cyclic frequency for each activity shouldbe physiologically relevant. If an accelerated or other non-physiological rate is used, then a justification consideringlubrication, thermal, and kinematic effects should be provided.6.3 Distribution of Activity MotionsThe testing systemshall be equipped with a means to select and run differentensembles of reference waveforms representing various activi-ties of daily living (ADLs). The six activities shall be per-form
