1、Designation: F3141 15F3141 17Standard 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 i
2、n 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 all contribute to the wear, degradation and damage of implantedprosthetics. Simulating a varie
3、ty of functional activities promises more realistic testing for wear and damage mode evaluation.Such activities are often called activities of daily living (ADLs).ADLs identified in the literature include walking, stair ascent anddecent, sit-to-stand, stand-to-sit, squatting, kneeling, cross-legged
4、sitting, into bath, out of bath, turning and cutting motions (1-7).2Activities other than walking gait often involve an extended range of motion and higher imposed loading conditions which havethe ability to cause damage and modes of failure other than normal wear (8-10).1.2 This document provides g
5、uidance for functional simulation that could be used to evaluate in vitro the durability of kneeprosthetic devices under force control.1.3 Function simulation is defined as the reproduction of loads and motions that might be encountered in activities of dailyliving but it does not necessarily cover
6、every possible type of loading. Functional simulation differs from typical wear testing inthat it attempts to exercise the prosthetic device through a variety of loading and motion conditions such as might be encounteredin situ in the human body in order to reveal various damage modes and damage mec
7、hanisms that might be encountered throughoutthe life of the prosthetic device.1.4 Force control is defined as the mode of control of the test machine that accepts a force level as the set point input and whichutilizes a force feedback signal in a control loop to achieve that set point input. For kne
8、e simulation, the flexion motion is placedunder angular displacement control, internal and external rotation is placed under torque control, and axial load, anterior posteriorshear and medial lateral shear are placed under force control.1.5 This document establishes kinetic and kinematic test condit
9、ions for several activities of daily living, including walking,turning navigational movements, stair climbing, stair descent, and squatting. The kinetic and kinematic test conditions areexpressed as reference waveforms used to drive the relevant simulator machine actuators. These waveforms represent
10、 motion, asin the case of flexion extension, or kinetic signals representing the forces and moments resulting from body dynamics, gravitationand the active musculature acting across the knee.1.6 This document does not address the assessment or measurement of damage modes, or wear or failure of the p
11、rostheticdevice.1.7 This document is a guide. As defined by ASTM in their “Form and Style for ASTM Standards” book in section C15.2, “Astandard guide is a compendium of information or series of options that does not recommend a specific course of action. Guidesare intended to increase the awareness
12、of information and approaches in a given subject area. Guides may propose a series ofoptions or instructions that offer direction without recommending a definite course of action. The purpose of this type of standardis to offer guidance based on a consensus of viewpoints but not to establish a stand
13、ard practice to follow in all cases.” The intentof this guide is to provide loading profiles and test procedures to develop testing that might be used for wear, durability or othertypes of testing of total knee replacements. As noted in this definition, a guide provides guidance on testing, but does
14、 not requirespecific testing. Thus, for example, if a user is unable to control one mode of force control given in the load profiles, that user isnot required to perform that mode of loading.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It
15、 is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1 This guide is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct r
16、esponsibility of Subcommittee F04.22on Arthroplasty.Current edition approved Dec. 15, 2015June 1, 2017. Published February 2016July 2017. Originally approved in 2015. Last previous edition approved in 2015 asF314115. DOI: 10.1520/F314115.10.1520/F3141-17.2 The boldface numbers in parentheses refer t
17、o the list of references at the end of this standard.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes acc
18、urately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United St
19、ates11.9 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers
20、to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3E74 Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing MachinesE2309 Practices for Verification of Displacement Measuring Systems and Devices Used in Material Testing MachinesE2624 P
21、ractice for Torque Calibration of Testing Machines2. Reference Frame System (see Fig. 1)2.1 Two right-handed coordinate systems are defined as reference frames; one with an origin at OT fixed to the tibia and a secondwith an origin at OF fixed to the femur.2.2 Displacements (rotations and translatio
22、ns) shall mean displacements of the tibial component relative to the femoralcomponent. The anatomical axes correspond to the mechanical axes described by Grood and Suntay (11).Table 1 shows themechanical axes and abbreviations corresponding to each anatomical axis.2.3 The orientation and location of
23、 the axes of the reference frames follow the approach defined by Pennock (12). However,to accommodate the simulator machine (versus anatomical) setting several modifications are made to the Pennock approach, asdescribed in 3.42.4.2.4 The femoral reference frame defines three coordinate axes, XF, YF,
24、 and ZF all coincident at the origin OF. The flexion axis,XF, shall be defined as collinear with a line passing through the coordinates of the average center of curvature of the posterior 90degrees of condylar arc. The average center of curvature shall be developed individually for the medial and la
25、teral condyles basedTwo righted-handed reference frames, OF and OT, are embedded in and move with the femur and tibia respectively. The coordinate system and signs are based on aright knee and forces and moments are considered to be applied to the tibia shaft with reaction forces acting at the joint
26、 articular surface.FIG. 1 Reference Frame SystemF3141 172on regular increments of angle from 0 to 90 degrees of posterior arc (the transepicondylar line may be substituted for the averagecenter of curvature if the manufacturer specifies that reference frame for surgical alignment purposes). The long
27、 axis of the femur,ZF, lies on a line passing through the center of the femoral head which extends to the medial lateral midpoint of the trans-condylarline, lying on the XF axis, connecting the most medial and most lateral points of the medial and lateral femoral condyles at theirmost distal project
28、ion. The ZF axis shall be perpendicular to the XF axis and the YF axis shall be defined as the cross product ofthe ZF and XF axes.2.5 The tibial reference frame defines three coordinate axes, XT, YT, and ZT, all coincident at the origin OT. The anatomicallong axis of the tibia, ZT, is defined by a l
29、ine extending from the center of the tibial intercondylar eminence to the center of theankle (12). This definition shall be adopted for this standard. The XT, YT, axis shall be defined with the knee in full extension andin a neutral configuration. In that configuration the XT axis shall be parallel
30、to the femoral XF axis and the YT axis will be coplanarwith the plane of the YF and ZF axes. The XT and YT axes will be mutually perpendicular to the ZT axis. The origin OT of thetibial coordinate system shall be located such that the XT axis is tangent to the most distal aspect of the tibial articu
31、lar bearingsurface.2.6 Grood and Suntay describe the motions of the knee using the notion of a mechanical linkage that constrains rotation andtranslation axes in a way that is thought to be clinically relevant. To define this motion a floating axis, YF is utilized. This axisis labeled the abduction
32、axis. The abduction axis remains perpendicular to both the XF axis and the ZT axis in all configurations.The abduction axis is rotated about the XF axis by an arc equal to flexion-extension arc.3. Terminology3.1 Definitions:3.1.1 activity model, nan activity model provides a kinematic and kinetic de
33、scription of a particular physiological activity.Each activity model shall provide a set of time series data that represents one cycle of the subject activity. The time series dataprovided by an activity model are used as inputs to control the motions and forces of the test machine. The time series
34、data requiredto characterize each activity are: (1) axial force, (2) flexion-extension angle, (3) axial tibial torque, (4) anterior-posterior force, and(5) medial-lateral force. These torques or forces may result in the motion of the femur or tibial relative to the other. How thesemotions are descri
35、bed may be machine-dependent, as to whether it is a motion of the tibia relative to the femur or the femur relativeto the tibia. The following descriptions are frequently described as motion of the tibia, but could also be described as motion ofthe femur.3.1.2 activities of daily living, ADLs, nthes
36、e are the physiological activities to which a human knee may be subject during thecourse of normal living. Typical ADLs include: high frequency maneuvers such as walking and turning; navigational maneuverssuch as cross over turning and pivot turning; deep knee flexion maneuvers such as squatting, st
37、air ascent and descent; high loadingmaneuvers such as stumbling; and athletic activities.3.1.3 AP translation, dTap or dTy mm, ntranslation of the tibial component along the YT axis (anterior posterior axis); apositive displacement moves the tibia in the anterior direction. The magnitude of the disp
38、lacement is expressed relative to thereference position.3.1.4 AP force, f Tap or f Ty N, napplied anterior or posterior force acting on the tibial component parallel to the YT axis. Apositive AP force acts in the positive YT direction and will result in an anterior translation of the tibia.3.1.5 app
39、lied force, napplied force is that force acting on the joint originating from external sources (includes themusculature). When magnitude and direction are specified the applied force shall be considered to be acting on the tibial shaft withbalancing reaction forces at the joint surface.3.1.5.1 Discu
40、ssionThe forces acting across the knee are partitioned into applied and constraint forces while the constraint forces are furtherpartitioned into joint reaction force and soft tissue constraint force. The applied force is comprised of the sum of the influencesof gravitation, body dynamics, and the a
41、ction of the active musculature. The joint reaction force is comprised of the influence ofall of the mechanisms which contribute to the forces of contact acting on the articular joint surface. The soft tissue constraint forceTABLE 1 Anatomical Meaning of Coordinate System Axes andAbbreviationsAnatom
42、ical Axis Coordinate Axis AbbreviationsMedial Lateral XF MLAnterior Posterior YT APAxial ZT AXFlexion Extension XF FEInternal External Rotation ZT IEAbduction Adduction YF AAF3141 173is comprised of the sum of all of the influences of the passive soft tissue structure which is dominated by the elast
43、ic and viscoelasticresponse of the ligaments and capsular structure surrounding the joint.3.1.6 joint coordinate system, JCS, nthe coordinate system and kinematic chain described by Grood and Suntay to representthe translational and rotational axes and motions of the knee.3.1.7 neutral position, nth
44、is is the position where the forces (or torques) are zero and corresponds to zero on the force (ortorque) deflection graphs defining the constraint forces and torques.3.1.8 reference orientation, nthe reference orientation is the relative alignment of the tibial and femoral components definedby the
45、manufacturer as the desirable alignment at full extension and neutral IE rotation.3.1.9 reference position, nthe reference position is determined with the prosthetic components aligned in the referenceorientation.The reference position is that position on theAPand MLaxis where an axial load results
46、in noAPor MLreaction force.This may be determined experimentally in the test machine by applying 100 N of axial load and then exercising the machinethrough a range of AP or ML motion while recording the corresponding AP or ML reaction force and displacement. The midpointof the minimum cusp of the fo
47、rce displacement curve is the reference position.3.1.9.1 DiscussionThe reference position may be determined analytically or graphically as that point where, when in the reference orientation, thesurface normal of contact points of the femoral and tibial components are collinear with the axial load a
48、xis.4. Significance and Use4.1 The purpose of this test guide is to provide load profile information on how to one could test a total knee replacement inorder to evaluate in vitro its function and wear during several types of knee motions.motions as described in 4.2 and 4.3.4.2 This test guide may h
49、elp characterize the magnitude and location of implant wear as an implant is repetitively movedaccording to specified load and displacement waveforms.4.3 This test guide may also help characterize the functional limitations of a total knee replacement as its motion is guided bythese waveforms. These limitations may be observed as impingement, subluxation or high loading in the soft tissue constraints,whether they are represented physically or virtually.4.4 The motions and load conditions in vivo will, in general, differ from the load and motions defined
