1、Designation: F 2582 08Standard Test Method forImpingement of Acetabular Prostheses1This standard is issued under the fixed designation F 2582; 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 p
2、arentheses 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 measuring therange of motion, impingement, and dislocation of a femoralhead assembly and acetabular prosth
3、esis.1.2 This test method covers the procedure for static andcyclic fatigue tests.1.3 This test method may be used to evaluate single pieceacetabular prostheses, modular prostheses, and constrainedprostheses manufactured from polymeric, metallic, or ceramicmaterials.1.4 The values stated in SI units
4、 are regarded as thestandard.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
5、 prior to use.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE 467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemF 2033 Specification for Total Hip Joint Prosthesis and HipEndoprosthesis Bearing Su
6、rfaces Made of Metallic, Ce-ramic, and Polymeric MaterialsF 2091 Specification for Acetabular Prostheses3. Terminology3.1 Definitions:3.1.1 component separationthe disruption of a connectionbetween components. May be stable or unstable.3.1.2 dislocationthe loss of normal physical contact be-tween op
7、posing components, usually indicated by large sepa-ration and a loss of stability.3.1.3 dislocation momentthe maximum torsional moment(N-m) measured at the point of dislocation. See Fig. 6.3.1.4 femoral headconvex spherical bearing member forarticulation with the natural acetabulum or prosthetic ace
8、tabu-lum.3.1.5 impingementthe point at which two opposing com-ponents collide to restrict motion, usually indicated by a sharpchange in force or moment. See Fig. 3 and Fig. 6.3.1.6 impingement momentthe moment (N-m) measuredor applied at the point of impingement.3.1.7 joint reaction forcethe force d
9、irected normal to thecontacting surfaces between two opposing articulating compo-nents.3.1.8 locking mechanismthe pieces of various compo-nents that contribute to the fixing of one component to another.3.1.9 range of motionthe effective pattern of motionlimited by impingement. In one plane this is m
10、easured fromone impingement point to the opposite impingement point.3.1.10 subluxationpartial dislocation.4. Summary of Test Method4.1 Acetabular prostheses are evaluated for range of motionuntil impingement. The impingement behavior is measured upto a dislocation or failure point. Modular acetabula
11、r prosthesesmay be evaluated for additional failure mechanisms includingseparation, loosening, fracture, and deformation of any com-ponent or locking mechanism, or both.4.2 This test method may be used to evaluate static ordynamic characteristics. Various joint reaction forces andimpingements may be
12、 applied in order to simulate knownclinical conditions.5. Significance and Use5.1 The test method may be used to evaluate and compareacetabular prostheses to assess the relative degree of constraintfor the prosthesis and the damage tolerance under controlledlaboratory conditions.1This test method is
13、 under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved June 1, 2008. Published July 2008.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact
14、 ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 It is recognized that
15、 there are several clinical failuremodes for acetabular prostheses and that this test method mayor may not be capable of reproducing them.6. Apparatus6.1 One axis must be capable of applying either a constantjoint reaction force for static and dynamic loading or aphysiological waveform for dynamic l
16、oading.6.2 A second axis must be capable of controlling andmonitoring angular displacement and torque.6.3 The equipment may be electromechanical, servo-hydraulic or other, as long as it meets the requirements ofPractices E4and E 467 for force verification.6.4 The joint reaction force must be applied
17、 through uncon-strained fixturing that allows for the separation of the acetabu-lar prosthesis from the femoral prosthesis during the impinge-ment and dislocation test. See Fig. 1 for representative fixture.See Fig. 2 for the test set-up.7. Sampling and Test Specimens7.1 All acetabular and femoral h
18、ead components shall berepresentative of implant quality products. This shall includeany sterilization processes if the sterilization may affect theresults.7.2 Femoral neck components shall have geometries repre-sentative of finished product but may be manufactured fromnon-implant grade materials.7.
19、3 A minimum of five assemblies shall be tested under anyset of boundary conditions chosen to determine the static rangeof motion and dislocation moment.7.4 Multiple tests may be performed on each specimen. Theappropriateness of performing multiple tests on the samecomponents will depend on the type
20、of testing and will requirecareful monitoring and reporting of component properties.FIG. 1 Representative Unconstrained Planar Bearing Fixture forFemoral ComponentFIG. 2 Schematic Representation of the Test SetupFIG. 3 Schematic Representation of the Test Setup at the Pointof ImpingementFIG. 4 An Ex
21、ample Test SetupF25820827.5 Precondition the specimens for 24 h in the laboratorytest environment, for example 25 6 3C and 50 6 10 %relative humidity (RH).7.6 Precondition the specimens for 48 h in the test environ-ment if this is water at 37 6 2C.8. Procedure8.1 Static Range of Motion (ROM) and Dis
22、location Testing:8.1.1 See Fig. 2 for a schematic representation of the testsetup. See Figs. 4 and 5 for an example setup for testing.8.1.2 Mount a femoral head assembly on the main jointreaction force actuator. The assembly shall consist of a femoralhead and stem neck region for the minimum length
23、that maycontact the acetabular component.8.1.3 Mount an acetabular prosthesis onto a separate butorthogonal actuator (an axis perpendicular to the main jointreaction force axis). Careful attention should be given to theposition of the acetabular component relative to the center ofthe actuator that w
24、ill rotate the component (see Fig. 2).8.1.4 Static tests do not require lubricant but water may beused if desired.8.1.5 Apply a joint reaction force. A force of 225 N isrecommended for evaluation of range of motion. Higher forcesmay also be used and 1000 N is recommended for determina-tion of bounda
25、ry conditions for dynamic testing.8.1.6 Rotate the acetabular prosthesis around the femoralhead under angular displacement control until impingementoccurs in the direction of rotation. An angular displacementrate of 5/s is recommended. Measure the total range of motionup to the impingement point in
26、both directions of rotation.NOTE 1This test method evaluates characteristics of acetabular pros-theses in one plane and many prostheses exist as asymmetric designs. Thevariation in geometry of any single prosthesis may be evaluated bychoosing different orientations for the initial positioning of the
27、 prosthesisand then repeating the measurement procedure. Physiologically relevantpositions may be tested by changing the position of the acetabular cup. Atypical position would place the acetabular component at an angle toreplicate a 45 superior inclination while measuring ROM and dislocationevents
28、during rotation that simulates a flexion/extension action of thefemoral component.NOTE 2Computer models may be used to evaluate the range ofmotion of acetabular prostheses.8.1.7 The dislocation moment may be measured by continu-ing the angular displacement beyond impingement until dislo-cation occur
29、s.NOTE 3The angular displacement rate may be adjusted to simulatethe intended cyclic test rate.8.1.8 Measure the dislocation moment with an apparatusthat has an accuracy of at least 0.2 N-m.8.1.9 Continuously record torque and displacement data at asufficient rate to capture the peak moment and prov
30、ide a graphof moment versus angular displacement (see Fig. 6).8.2 Unidirectional Dynamic Impingement Testing:8.2.1 This method may be used for the unidirectional cyclicor dynamic evaluation of acetabular prostheses with thefollowing considerations.8.2.2 An environment of water at 37 6 2C shall be us
31、ed toprovide lubrication and temperature control during the test.8.2.3 A constant joint reaction force of 1000 N is recom-mended. Higher forces may be used.8.2.4 Apply a moment of 10 N-m or 70 % of the peakdislocation moment (see Fig. 6) measured statically (whicheveris less) using a sinusoidal forc
32、ing function with R = 0.3.8.2.5 Test for a maximum of one million cycles or failure,whichever comes first. Failure is defined in 8.4.8.2.6 The maximum test frequency shall be 10 Hz.8.3 Bi-directional Dynamic Impingement Testing:8.3.1 Impingement testing may be controlled with a sinu-soidal forcing f
33、unction ranging from +10 N-m to 10 N-m or670 % of the peak dislocation moment. This will cause theacetabular prosthesis to swing through a full range of motion inone plane.8.3.2 The maximum test frequency shall be 1 Hz.8.3.3 Test for a maximum of one million cycles or failure,whichever comes first.
34、Failure is defined in 8.4.8.4 Potential failure modes may include, but are not limitedto, the following:8.4.1 Dislocation of the femoral component from the ac-etabular component.8.4.2 Separation of a modular acetabular liner from anacetabular shell.8.4.3 Fracture of any prosthetic component.8.4.4 Gr
35、oss deformation of any prosthetic component.FIG. 5 An Example Test Setup Showing the Point of ImpingementFIG. 6 Representative Moment versus Angular DisplacementResult Obtained for the Static ROM and Dislocation TestF25820838.4.5 Fracture and/or failure of a locking mechanism be-tween modular compon
36、ents.9. Report9.1 The report shall include the following information:9.1.1 Product codes, lot numbers, and special processes thatmight influence the test results should be noted.9.1.2 Product sizing, style and specific dimensions (Speci-fications F 2091 and F 2033) relative to the performance of the
37、test shall be recorded including the specific or simulated neckregion of the femoral prosthesis.9.1.3 Test environment.9.1.4 ROM for each plane characterized during testing.9.1.5 Graph of moment versus angular displacement (seeFig. 6).9.1.6 Impingement moment used for any dynamic tests.9.1.7 Disloca
38、tion moment measured during the static test.9.1.8 Description of failure mechanisms.9.1.9 Moment versus cycles to failure graph for dynamictests.9.1.10 Joint reaction force.9.1.11 Description of the damage to the acetabular prosthe-sis incurred during the test.9.1.12 Photographic documentation of th
39、e damage to theacetabular prostheses incurred during the test.9.1.13 Change in the angular displacement of the acetabularprosthesis at the end of the dynamic test compared to thebeginning of the test.10. Precision and Bias10.1 A precision and bias statement does not exist for thistest method because
40、 round robin testing has not been per-formed.11. Keywords11.1 acetabular prosthesis; dislocation; impingement; rangeof motionAPPENDIX(Nonmandatory Information)X1. RATIONALEX1.1 This test method was developed to provide a stan-dardized means for assessing the functional performance of anacetabular pr
41、osthesis under laboratory conditions. This testmethod may be used to evaluate the range of motion, impinge-ment and dislocation of acetabular prostheses, and lockingmechanism characteristics.X1.2 It is recognized that there are several clinical failuremodes for acetabular prostheses and that this te
42、st method mayor may not be capable of reproducing them. This test methoddoes not purport to accurately recreate in-vivo conditions.X1.3 Although surgical placement may be the largest factorinfluencing dislocation between femoral and acetabular pros-theses, the design allowances for ROM, impingement
43、toler-ance, and resistance to dislocation will contribute and thereforeshould be assessed using a standardized method.X1.4 There are several references that may be useful inunderstanding this test method and the clinical rationale for thistest method. Some are listed in the Bibliography of this test
44、method.X1.5 It is noted that the joint reaction force that animplanted acetabular prosthesis encounters is not static oruniform, but can be quite variable. A constant force equivalentto an above average body weight (1000 N) was chosen for thedynamic test methods to standardize a high load case. Tode
45、termine the range of motion in the static test, 225 N waschosen to prevent failure of the components or materials duringthat test.X1.6 Due to the variety of possible failure mechanisms,depending on the design of the implant system, both static anddynamic testing have been described.X1.7 A maximum cy
46、cle count of one million was chosenfor the dynamic testing with the belief that many failuremechanisms can be elicited in this time frame. One may chooseto continue testing to a higher number.X1.8 It is recognized that there are other methods fortesting acetabular prostheses. Based on various goals,
47、 investi-gators may choose to deviate from the test method definedhere.F2582084BIBLIOGRAPHY(1) Nadzadi, M. E., et al, “Effects of Acetabular Component Orienta-tion on Dislocation Propensity for Small-Head-Size Total HipArthroplasty,” Clin Biomech., Vol 17, No. 1, Jan 2002, pp. 3240.(2) Robbins, G. M
48、., et al, “Treatment of Hip Instability,” Orthop ClinNorth. Am., Vol 32, No. 4, Oct 2001, pp. 593610.(3) Scifert, C. F., et al, “Experimental and Computational Simulation ofTotal Hip Arthroplasty Dislocation,” Orthop. Clin. North Am., Vol32, No. 4, Oct 2001, pp. 553567.(4) Yamaguchi, M., et al, J Ar
49、throplasty, Vol 15, No. 3, Apr 2000, pp.303313. (39 % of 111 retrievals from a single mfg. indicatedimpingement on the posterior aspect of the acetabulum. Probablydue to femoral extension and external rotation during toe off. Cupswith impingement were more anteverted than those without.Inverse relation between impingement and the size of the femoralhead.)(5) DLima, D. D., et al, JBJS, Vol 82, No. 3, Mar 2000, pp. 315321.(Changes in cup anteversion and abduction angles combined withchoice of skirted femoral heads will reduce range of motion andincrease chance
