1、Designation:F238504(Reapproved 2010)Standard Test Method forDetermining Femoral Head Penetration into AcetabularComponents of Total Hip Replacement Using ClinicalRadiographs1This standard is issued under the fixed designation F2385;the number immediately following the designation indicates the year
2、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 provides guidance for the measurementof the rel
3、ative displacement of the femoral head and acetabularcomponent that result from wear and deformation occurring atthe articular interface of a total hip replacement from sequen-tial clinical radiographs.1.2 This test method is primarily intended for use inevaluating patients receiving THRs composed o
4、f a polyethyl-ene acetabular component articulating against a metal orceramic femoral head.1.3 So-called hard-on-hard articulations such as metal-on-metal and ceramic-on-ceramic THRs are not intended to bedirectly addressed.1.4 This test method will focus on computer assisted com-putational methodol
5、ogies for measuring relative displacementsover time but not to the exclusion of other methodologies.1.5 This test method describes methods for conducting aradiographic wear/creep study utilizing various computationalmethods and is not intended to promote or endorse a particularmethod.1.6 It is not t
6、he intent of this test method to provide detailedinstructions in the use of the various computational methods,which is contained in the respective user manuals.1.7 It is the intent of this test method to enable comparisonsof relative displacements occurring in groups of patientsreceiving different f
7、ormulations of bearing materials.It mustbe recognized,however,that there are many possible variationsin the in vivo conditions.A single clinical study may not beuniversally representative.1.8 This test method is not intended to be a performancestandard.It is the responsibility of the user of this te
8、st methodto characterize the safety and effectiveness of the prosthesisunder evaluation.1.9 The values stated in SI units are to be regarded as thestandard,with the exception of angular measurements,whichmay be reported in either degrees or radians.1.10 The use of this standard may involve the opera
9、tion ofpotentially hazardous radiographic equipment and does notpurport to address the safety precautions associated withradiography.It is the responsibility of the user of this standardto define and establish appropriate safety practices.Thestandard does not determine the applicability of regulator
10、ylimitations prior to operating radiographic equipment.1.11 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 o
11、f regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 All radiographic terminology is co
12、nsistent with thereferenced standards,unless otherwise stated.3.2 Definitions:3.2.1 radiostereometric analysis(RSA)a method devel-oped by Goren Selvik for measuring relative motion betweentwo parts from clinical radiographs(1).3This method utilizesin vivo tantalum beads,an external reference cage,an
13、d twox-ray generators which take two exposures simultaneously.There are several commercially available software/hardwarepackages for RSA analysis.1This test method is under the jurisdiction ofASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of Subcommi
14、tteeF04.22 on Arthroplasty.Current edition approved Aug.15,2010.Published October 2010.Originallyapproved in 2004.Last previous edition approved in 2004 as F2385 04.DOI:10.1520/F2385-04R10.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceas
15、tm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,
16、PA 19428-2959.United States1 3.2.2 markerstantalum beads 1.0 mm,0.8 mm,or 0.5 mmin diameter.3.2.2.1 implant markersin vivo markers placed on theimplant in order to define the implant as a rigid body.3.2.2.2 cage markerstantalum beads held in an externalreference frame used to create a three dimensional coordinatesystem for measuring relative displacements.3.2.2.3 segmenta three dimensional rigid body defined bya minimum of three markers.3.2.3 edge detectionmethod of image analysis used todetermi