ASTM_F_1223_-_14.pdf

Designation:F122314Standard Test Method forDetermination of Total Knee Replacement Constraint1This standard is issued under the fixed designation F1223;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 This test method covers the establishment of a databaseof total knee replacement(TKR)motion characteristics withthe intent of developing guidelines for the assignment ofconstraint criteria to TKR designs.(See the Rationale inAppendix X1.)1.2 This test method covers the means by which a TKRconstraint may be quantified according to motion delineated bythe inherent articular design as determined under specificloading conditions in an in vitro environment.1.3 Tests deemed applicable to the constraint determinationare antero-posterior draw,medio-lateral shear,rotary laxity,valgus-varus rotation,and distraction,as applicable.Alsocovered is the identification of geometrical parameters of thecontacting surfaces which would influence this motion and themeans of reporting the test results.(See Practices E4.)1.4 This test method is not a wear test.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesF2083 Specification for Knee Replacement Prosthesis3.Terminology3.1 DefinitionsItems in this category refer to the geo-metrical and kinematic aspects of TKR designs as they relate totheir human counterparts:3.1.1 anterior curvature,na condylar design which isgenerally planar except for a concaveupward region anteri-orly on the tibial component.3.1.2 anterior posterior(AP),nany geometrical lengthaligned with the AP orientation.3.1.3 AP displacement,nthe relative linear translationbetween components in the AP direction.3.1.4 AP draw load,nthe force applied to the movablecomponent with its vector aligned in the AP direction causingor intending to cause an AP displacement.3.1.5 biconcave,na condylar design with pronounced APand ML condylar radii seen as a“dish”in the tibial componentor a“toroid”in the femoral component.3.1.6 bearing surface,nthose regions of the componentwhich are intended to contact its counterpart for load transmis-sion.3.1.7 condyles,nentity designed to emulate the jointanatomy and used as a bearing surface primarily for transmis-sion of the joint reaction force with geometrical propertieswhich tend to govern the general kinematics of the TKR.3.1.8 distraction,nthe separation of the femoral compo-nent(s)from the tibial component(s)in the z-direction.3.1.9 femoral side constraint,nthat constraint provided bythe superior articulating interfaces,determined by fixing theinferior surface of the mobile bearing component duringtesting.3.1.10 flexion angle,nthe angulation of the femoral com-ponent(about an axis parallel to the y-axis)from the fullyextended knee position to a position in which a“local”verticalaxis on the component now points posteriorly.3.1.10.1 DiscussionFor many implants,0 of flexion canbe defined as when the undersurface of the tibial component isparallel to the femoral component surface that in vivo contactsthe most distal surface of the femur.This technique may not bepossible for some implants that are designed to have a posteriortilt of the tibial component.In these cases,the user shallspecify how the 0 of flexion position was defined.3.1.11 hinge,na mechanical physical coupling betweenfemoral and tibial components which provides a single axisabout which flexion occurs.1This test method is under the jurisdiction ofASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved May 15,2014.Published June 2014.Originallyapproved in 1989.Last previous edition approved in 2012 as F1223 08(2012).DOI:10.1520/F1223-14.2For referenced ASTM standards,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,PA 19428-2959.United States1 3.1.12 hyperextension stop,na geometrical feature whicharrests further progress of flexion angles of negative value.3.1.13 inferior articulating interfaces,nany interface inwhich relative motion occurs between the underside of themobile bearing component and the tibia