1、Designation: F3140 17Standard Test Method forCyclic Fatigue Testing of Metal Tibial Tray Components ofUnicondylar Knee Joint Replacements1This standard is issued under the fixed designation F3140; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 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 a procedure for the fatiguetesting of metallic tibial trays used in
3、partial knee jointreplacements.1.2 This test method covers the procedures for the perfor-mance of fatigue tests on metallic tibial components using acyclic, constant-amplitude force. It applies to tibial trays whichcover either the medial or the lateral plateau of the tibia.1.3 This test method may
4、require modifications to accom-modate other tibial tray designs.1.4 This test method is intended to provide useful,consistent, and reproducible information about the fatigueperformance of metallic tibial trays with unsupported mid-section of the condyle.1.5 The values stated in SI units are to be re
5、garded 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, health and environmental prac
6、tices and deter-mine the applicability of regulatory limitations prior to use.1.7 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 an
7、d Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:E467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemE468 Practice for Presentation of Constant Amplitude F
8、a-tigue Test Results for Metallic MaterialsE739 Practice for StatisticalAnalysis of Linear or LinearizedStress-Life (S-N) and Strain-Life (-N) Fatigue DataE1823 Terminology Relating to Fatigue and Fracture TestingE1800 Specification for Adhesive for Bonding Foam CoredSandwich Panels (160F Elevated H
9、umidity Service),Type I PanelsE1823 Terminology Relating to Fatigue and Fracture TestingE2083 Classification for Building Construction FieldRequirements, and Office Overhead formation of a crack detectable by eye; fluorescent dyepenetrant, or other non-destructive means; or exceeding apredetermined
10、deflection limit.10. Report10.1 Report the fatigue test specimens, procedures, andresults in accordance with Practice E468.10.2 In addition, report the following parameters: tibial traymaterial, spacer diameter and thickness, indenter diameter orsmallest femoral component contact area at 0-60 degree
11、flexion, overall anteroposterior and mediolateral dimensions ofthe tray, location of anteroposterior and mediolateral center-lines (for asymmetric tibial trays), tibial condyle maximumdeflection during test, dml, dap, fixation method, largest com-pressive force, R value, cycles to failure, mode and
12、location offailures, test environment, and test frequency. The method fordetermining the loading location on the tibial tray (that is, dml,and dap) shall be documented.10.3 Pictures of the tray and test setup pre- and post-testingshould be included in the report. If tibial tray fractured duringtest,
13、 pictures should include superior and inferior views todocument the location of crack and failure mode.10.4 If any test results are excluded for any reason, thereport must include adequate documentation justifying theirexclusion.11. Keywords11.1 arthroplasty; orthopaedic medical devices; tibial com-
14、ponents; unicondylar knee arthroplastyF3140 174APPENDIX(Nonmandatory Information)X1. RATIONALEX1.1 Fractures of tibial trays in Unicondylar Knee Replace-ment (UKR) have occurred in clinical applications (2, 3). Thetray design, quality of bone, flatness of the cut surface andother features contribute
15、 to implant fracture. One recognizablemode of clinical failure occurs when the anterior and posterioredges of the implant are resting on cortical bone while themid-section is unsupported. This can be due to the skiving ofthe cutting tool or the posterior bone fragments left behind dueto the breaking
16、 off of the cut bone to prevent posterolateralcorner ligament damage.As the body loads are applied throughthe tray of the prosthesis, significant stresses can result at thearea where the tray is unsupported. Because it is believed thatthis lack of support is the primary reason behind fracture of the
17、tibial trays, this practice was chosen as a simplified model touse in fatigue testing of actual implants.X1.2 It is recognized that for some materials the environ-ment may have an effect on the response to cyclic loading. Thetest environment used and the rationale for that choice shall bedescribed i
18、n the test reportX1.3 It is also recognized that actual in vivo loadingconditions are not of constant amplitude. However, there isinsufficient information available to create standard load spec-trums for metallic tibial components. Accordingly, a simpleperiodic constant amplitude force is recommende
19、d.X1.4 Worst-case loading of the tibial tray may vary, depend-ing on material, design, and clinical indications. The researchershall evaluate the possible clinical and design-related failuremodes and attempt to determine a worst-case situation. Asstated above, loss of central medial bone support has
20、 beenclinically observed and is thus incorporated in this practice.Also, as the method of heat treatment can affect the strength ofthe tibial tray material, it shall be considered. For example, thehigh temperature sintering treatment used to apply a porouscoating to a tibial tray may affect the fati
21、gue strength of thetibial tray.X1.5 The size of the tibial tray to be tested shall bedetermined by the investigator. In general, the worst-case sizeshall be chosen based on evaluation or experience, or both. Ina design with a constant tray thickness, maximizing the A/Plength will result in the large
22、st moment arm and therefore thehighest stresses in the tray; however, a tray of non-uniformthickness may not adhere to this rule. There may also be areason why an investigator wishes to test a size that is not worstcase. This practice may also be used for this purpose.X1.6 The tolerance chosen for t
23、he alignment of the tibialtray is based on finite element analysis of a tibial tray designwith and without a central keel. The analysis represents onedesign under specific boundary conditions and is shown as oneexample of the variation that can occur due to tibial traymisalignment. The conclusions o
24、f this analysis were as fol-lows:X1.6.1 The required tolerance limits (61mmand62)were chosen to minimize the change in stress while ensuring areasonable test setup.X1.7 In developing this practice, it was recognized thatalternative methods for testing tibial trays exist. One such testmethod would in
25、clude fixing the anterior or posterior half ofthe implant and following a cantilever type test. This practiceattempts to simplify the loading conditions while addressingclinical failure modes of tibial tray designs. Based on variousgoals, investigators may seek to deviate from the test methoddefined
26、 here.X1.8 Specification E2083 includes a performance criteriafor the tibial baseplate (tray) fatigue test method, PracticeE1800. The specification states that “each of five specimensshall be tested and pass for 10 million cycles with no failuresusing a maximum load of 900N as a minimum requirement.
27、”The maximum load of 900N was established as described inthe reference document cited in Specification E2083 and wasbased on the failure mode observed from a legally marketedTKR. In order to fully understand the mechanical fatiguebehavior of the UKR, users are encouraged to determine asufficient sam
28、ple size to establish a Linearized Stress-Life(S/N) type curve to characterize the failure load and mode (forexample, unacceptable deformation, material loss,delamination, fracture). The number of cycles based on statis-tical methods to establish an S/N curve with the minimumsamples required may be
29、determined by using Practice E739.Once the run-out load is determined from the S/N curve, aminimum of five samples is recommended to be tested to 10million cycles (based on Practice E1800) with no failure at thepredetermined load. The load used should be justified based onphysiological loading param
30、eters expected to be encounteredthroughout the lifetime of the implant. Any sample that failsbefore the recommended 10 million cycle limit indicates thatthe tibial tray design does not consistently meet the run-outload criteria determined from the S/N curve.F3140 175REFERENCES(1) Yildirim, G. Parker
31、, J.2014. A New Method for UKR Tibial TrayFatigue Testing. Society for Biomaterials Annual Meeting.(2) Palumbo, B.T., Henderson, E.R., Edwards, P.K., Burris, B., Gutirrez,S., Raterman, S.J.2011. Initial Experience of the Journey-DeuceBicompartmental Knee Prosthesis. The Journal of Arthroplasty 6 (6,
32、Suppl): 4045.(3) Manzotti, A., Chemello, C., Pullen, C., Cerveri, P., Confalonieri,N.2013. An uncommon cause of cemented unicompartmental kneearthroplasty failure: fracture of metallic components. Knee Surgery,Sports Traumatology, Arthroscopy Journal 21: 25182522.ASTM International takes no position
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