1、Designation: F2028 17Standard Test Methods forDynamic Evaluation of Glenoid Loosening orDisassociation1This standard is issued under the fixed designation F2028; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 These test methods measure how much a prostheticanatomic glenoid component rocks or pivots following cyclicdisplacement of the
3、humeral head to opposing glenoid rims (forexample, superior-inferior or anterior-posterior). Motion isquantified by the tensile displacement opposite each loaded rimafter dynamic rocking. Similarly, these test methods measurehow much a prosthetic reverse glenoid component rocks orpivots following cy
4、clic articulation with a mating humeralliner. Motion is quantified by the magnitude of displacementmeasured before and after cyclic loading.1.2 The same setup can be used to test the locking mecha-nisms of modular glenoid components, for example, disasso-ciation of both anatomic and reverse shoulder
5、 components.1.3 These test methods cover shoulder replacement designswith monolithic or modular glenoid components for cementedfixation as well as reverse glenoid components for uncementedfixation.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are incl
6、uded in thisstandard.1.5 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 t
7、o use.1.6 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 TechnicalBarri
8、ers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesF1378 Specification for Shoulder ProsthesesF1839 Specification for Rigid Polyurethane Foam for Use asa Standard Material for Testing Orthopaedic Devices andInstruments3. Ter
9、minology3.1 Anatomic Total Shoulder Replacement (TSR) Definitions3.1.1 anatomic total shoulder arthroplasty system,nshoulder implant system that has a concave glenoid com-ponent and a convex humeral component design.3.1.2 anatomic glenoid component, nthe concave pros-thetic portion that replaces, in
10、 part or in total, the glenoid fossaof the scapula and articulates with the natural humeral head ora prosthetic replacement.3.1.3 glenoid backing, nthe metallic or composite mate-rial prosthetic portion of a multi-piece anatomic glenoidcomponent that attaches to the scapula.3.1.4 glenoid liner, nthe
11、 polymeric prosthetic portion of amultiple-piece anatomic glenoid component that articulateswith the humeral head.3.2 Reverse TSR Definitions3.2.1 reverse total shoulder arthroplasty system,nshoulder implant system that has a convex glenoid compo-nent and a concave humeral component design.3.2.2 rev
12、erse glenoid component, nthe convex prostheticportion that replaces the glenoid fossa of the scapula andarticulates with a concave prosthetic replacement of the hu-meral head in reverse total shoulder arthroplasty applications.The reverse glenoid may consist of one or more componentsfrom one or more
13、 materials; most commonly, the reverseglenoid is composed of a metal glenosphere that is modularlyconnected to a metal glenoid baseplate which is fixed to theglenoid fossa.1These test methods are under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and are the di
14、rect responsibility ofSubcommittee F04.22 on Arthroplasty.Current edition approved Dec. 1, 2017. Published January 2018. Originallyapproved in 2000. Last previous edition approved in 2014 as F2028 14. DOI:10.1520/F2028-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontac
15、t 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 StatesThis international standar
16、d was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.3 gl
17、enoid baseplate, nthe nonarticular portion of thereverse glenoid component that modularly connects to theglenosphere and is commonly fixed to the glenoid fossa of thescapula using bone screws without the use of cement.3.2.4 glenosphere, nthe convex prosthetic articular por-tion of the reverse glenoi
18、d component that articulates with theconcave prosthetic replacement of the proximal humerus orhumeral head (for example, the humeral liner).3.2.5 glenosphere thickness, nthe height of the truncatedsection of the sphere which composes the glenosphere. Notethat the difference between the glenosphere a
19、rticular radius andthickness defines the medial/lateral position of the glenoidcenter of rotation (see Fig. 1). The glenosphere thickness couldalso be affected by the geometric relationship between theglenosphere and the glenoid baseplate.3.2.6 humeral liner, nthe concave prosthetic portion of there
20、verse humeral component that replaces the proximal humerusor humeral head and articulates with the convex prostheticreplacement of the glenoid (for example, the glenosphere).3.3 Definitions Common to Anatomic and Reverse TSRs3.3.1 collar, nflange at the junction of the humeral neckand stem.3.3.2 kee
21、l, (or pegs), nsingle or multiple projections thatprovide resistance to translation or rotation of the glenoidcomponent, or both, by mating with cavities created in theglenoid fossa.3.3.3 necksegment connecting the head and the stem.3.3.4 glenoid plane, nin symmetrical anatomic glenoids,the glenoid
22、plane is defined by joining the two articular edges;in planar and asymmetric anatomic glenoids, it is defined bythe back (medial) surface. For a reverse shoulder it is definedas the plane created by the face of the glenoid baseplate (seeFig. 2).3.3.4.1 DiscussionAlthough the glenoid fossa is not tru
23、lya planar structure, the terms plane of the glenoid and glenoidplane have both been used in the scientific literature to describethe anatomic orientation of the glenoid.3.3.5 humeral head, nthe bearing member that articulateswith the glenoid.3.3.6 humeral component, nthe prosthetic portion thatrepl
24、aces, in part or in total, the proximal humerus or humeralhead and articulates with the natural glenoid fossa or aprosthetic replacement.3.3.7 humeral stem, nsegment intended for insertionwithin the humeral medullary canal.3.4 Definitions of Terms Specific to This Standard:3.4.1 anterior/posterior (
25、AP), nthe widest dimension ofthe glenoid component that is perpendicular to the SI axis (seeFig. 3 and Fig. 4).3.4.2 axial force; axial translation, nthe force anddisplacement, respectively, perpendicular to the glenoid plane.The axial force simulates the net compressive external andactive and passi
26、ve soft tissue forces (see Fig. 2).3.4.3 edge displacement, nthe translation, perpendicularto the glenoid plane, of a specific point on the outside edge ofthe glenoid, when subjected to loading (see Fig. 5, Fig. 6 andFig. 7).3.4.4 runout, na predetermined number of cycles at whichthe testing on a pa
27、rticular specimen will be stopped, and nofurther testing on that specimen will be performed.FIG. 1 Glenosphere ThicknessF2028 1723.4.5 shear force; shear translation, nthe force anddisplacement, respectively, parallel to the glenoid plane,applied, for example, in the superior/inferior or anterior/po
28、sterior direction. The shear force simulates the net externalshear and active and passive soft tissue forces (see Fig. 2).3.4.6 subluxation force, nthe peak shear force required forsubluxation (for example, the peak resistive force at theglenoid articular rim opposing movement of the humeral head).3
29、.4.7 subluxation translation, nthe distance from the gle-noid origin (see Fig. 3), parallel to the glenoid plane, to thepoint at which the subluxation load occurs.3.4.8 superior/inferior (SI), nthe longest dimension of theglenoid component (see Fig. 3 and Fig. 4).ANATOMIC SHOULDER GLENOID LOOSENINGT
30、EST METHOD4. Summary of Test Method4.1 The prosthetic glenoid component is fixed with bonecement into a bone substitute using the normal surgicaltechnique.4.2 The subluxation translation is determined experimen-tally on additional components. This is accomplished using abiaxial apparatus (see Fig. 5
31、) by applying an axial loadperpendicular to the glenoid, then translating the humeral headparallel to the glenoid plane until encountering a peak shearload. This is performed in both directions, corresponding to theFIG. 2 Glenoid Plane and Force DirectionsFIG. 3 Anatomic Glenoid Axes and OriginFIG.
32、4 Reverse Glenoid Baseplate AxesF2028 173direction of intended rocking (for example, superior-inferior,anterior-posterior, or an alternative angle).4.3 The edge displacements of the glenoid are measuredbefore cycling: a given axial load is first applied perpendicularto the glenoid, then the edge dis
33、placements are measured withthe humeral head in three positions: at the glenoid origin, andpositioned to 90 % of the subluxation translation (see X1.2), inboth directions, as defined in 4.2. (Cycling to 90 % of thesubluxation load would be acceptable, but is not practicalbecause of the large displac
34、ements, quick speeds, and deform-able polyethylene).4.4 The humeral head is cycled to 90 % of the subluxationdistance for a fixed number of cycles.4.5 The edge displacements (4.3) are either repeated follow-ing the cycling or measured continuously during the cycling.FIG. 5 Biaxial Testing Apparatus
35、for Anatomic ShouldersFIG. 6 Displacement Test ConfigurationF2028 1745. Significance and Use5.1 This test method is intended to investigate the resistanceof a glenoid component to loosening. Glenoid loosening is themost common clinical complication in total shoulder arthro-plasty (see X1.1). The met
36、hod assumes that loosening occursbecause of edge loading, often called the rocking-horse phe-nomenon.5.2 This test method can be used both to detect potentialproblems and to compare design features. Factors affectingloosening performance include articular geometry, flangegeometry, materials, fixatio
37、n design, bone quality, and surgicaltechnique.6. Apparatus and Equipment6.1 The test apparatus shall be constructed such that an axialforce is applied perpendicular to the glenoid plane and a shearforce is applied parallel to the glenoid plane (see Fig. 2). Fig.5 shows the axial force to be horizont
38、al and the shear force tobe vertical; however, this arrangement may be reversed.6.2 A bone substitute representing the strength or glenoidcancellous bone (see X1.5) shall be used. If a polyurethanefoam is used, it shall conform to Specification F1839.6.3 The glenoid and humeral head shall be enclose
39、d in achamber with water heated to 37 6 2C, at least for thedynamic portion of the test (see X1.6). A buffer may be added,if the tester deems this necessary.6.4 A means to measure the axial load, shear load, sheartranslation, and glenoid edge displacements is required. Ameans to measure the axial tr
40、anslation is desirable.6.5 The tests shall be performed on either mechanical orhydraulic load frames with adequate load capacity and shallmeet the criteria of Practices E4.7. Sampling and Test Specimens7.1 A minimum of three samples shall be tested. Additionalsamples may be used to reflect test vari
41、ability. At least twoadditional components should be used to determine the sub-luxation translation. The test may be conducted along thesuperior-inferior axis, the anterior-posterior axis, or anotheraxis of interest to the user.7.2 All glenoid components shall be in the final manufac-tured condition
42、. All plastic components shall be sterilizedaccording to the manufacturer-recommended specifications forclinical use.7.3 The humeral head shall include the identical radius orradii and material as the actual implant. Other features of thehumeral component such as the shaft may be omitted. Thesame he
43、ad may be used for all tests unless the surface becomesdamaged.7.4 Glenoid and humeral components are used in totalshoulder arthroplasty and should conform to the criteriaspecified in Specification F1378.8. Procedure8.1 The following steps are common to both the subluxation(4.2) and rocking (4.3 4.5
44、) tests:8.1.1 Secure the glenoid component in a bone substitutewith bone cement using the normal surgical procedure andinstrumentation. Do not perform tests until the cement hascured properly.8.1.2 Position the path of the humeral head on the glenoidwithin 60.5 mm (sideways) of the desired path, for
45、 example,by using a dye to locate the contact point of the humeral head;a dye is unnecessary for congruent prostheses. Locate thecenter of the path (for the subluxation test, this need not beFIG. 7 Alternative Displacement Test ConfigurationF2028 175exact; for the rocking test, the peak loads at eac
46、h rim duringcycling should be within 610 % of each other for symmetricaldesigns).8.1.3 Perform the static measurements (subluxation andedge displacements) either in air at room temperature or inwater at 37C. The cyclic testing shall be performed in 37Cwater (see 6.3, X1.3, and X1.6).8.1.4 Apply a gi
47、ven axial load to the glenoid, for example,750 6 7.5 N (see X1.4).8.2 Determine the subluxation translation experimentally onseparate components (see X1.2):8.2.1 After applying the axial load, displace the humeralhead at a constant rate to a given displacement, ensuring that apeak load is achieved i
48、n both directions. A rate of 50 mm/minis recommended to avoid polyethylene creep.8.2.2 Yielding is expected at the recommended load anddoes not constitute a failure. The test shall be terminated if theinsert of a modular glenoid disassociates.8.2.3 Record the axial load, subluxation load, and sublux
49、-ation translation.8.3 Measure the edge displacements before rocking:8.3.1 Create a foundation for measurements at both ends ofthe glenoid at a similar distance from the back surface of theglenoid for all prostheses. One possibility is to insert 2-mm-diameter screws into the outside edge at each end of theglenoid prosthesis, parallel to the articular surface (to avoidexiting either into the articular surface or into the bonesubstitute). Flatten the screw head parallel to the glenoid plane.Alternative methods are acceptable (see X1.8).8.3.2 Rest a
