ASTM F2582-08
(Test Method)Standard Test Method for Impingement of Acetabular Prostheses
Standard Test Method for Impingement of Acetabular Prostheses
SIGNIFICANCE AND USE
The test method may be used to evaluate and compare acetabular prostheses to assess the relative degree of constraint for the prosthesis and the damage tolerance under controlled laboratory conditions.
It is recognized that there are several clinical failure modes for acetabular prostheses and that this test method may or may not be capable of reproducing them.
SCOPE
1.1 This test method covers a procedure for measuring the range of motion, impingement, and dislocation of a femoral head assembly and acetabular prosthesis.
1.2 This test method covers the procedure for static and cyclic fatigue tests.
1.3 This test method may be used to evaluate single piece acetabular prostheses, modular prostheses, and constrained prostheses manufactured from polymeric, metallic, or ceramic materials.
1.4 The values stated in SI units are regarded as the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F2582 − 08
StandardTest Method for
Impingement of Acetabular Prostheses
This standard is issued under the fixed designation F2582; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 dislocation—the loss of normal physical contact be-
tween opposing components, usually indicated by large sepa-
1.1 This test method covers a procedure for measuring the
ration and a loss of stability.
range of motion, impingement, and dislocation of a femoral
head assembly and acetabular prosthesis. 3.1.3 dislocation moment—the maximum torsional moment
(N-m) measured at the point of dislocation. See Fig. 6.
1.2 This test method covers the procedure for static and
cyclic fatigue tests. 3.1.4 femoral head—convex spherical bearing member for
articulation with the natural acetabulum or prosthetic acetabu-
1.3 This test method may be used to evaluate single piece
lum.
acetabular prostheses, modular prostheses, and constrained
3.1.5 impingement—the point at which two opposing com-
prostheses manufactured from polymeric, metallic, or ceramic
materials. ponents collide to restrict motion, usually indicated by a sharp
change in force or moment. See Fig. 3 and Fig. 6.
1.4 The values stated in SI units are regarded as the
3.1.6 impingement moment—the moment (N-m) measured
standard.
or applied at the point of impingement.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.1.7 joint reaction force—the force directed normal to the
contacting surfaces between two opposing articulating compo-
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- nents.
bility of regulatory limitations prior to use.
3.1.8 locking mechanism—the pieces of various compo-
nents that contribute to the fixing of one component to another.
2. Referenced Documents
3.1.9 range of motion—the effective pattern of motion
2.1 ASTM Standards:
limited by impingement. In one plane this is measured from
E4 Practices for Force Verification of Testing Machines
one impingement point to the opposite impingement point.
E467 Practice for Verification of Constant Amplitude Dy-
3.1.10 subluxation—partial dislocation.
namic Forces in an Axial Fatigue Testing System
F2033 Specification for Total Hip Joint Prosthesis and Hip
4. Summary of Test Method
Endoprosthesis Bearing Surfaces Made of Metallic,
Ceramic, and Polymeric Materials
4.1 Acetabular prostheses are evaluated for range of motion
F2091 Specification for Acetabular Prostheses
until impingement. The impingement behavior is measured up
to a dislocation or failure point. Modular acetabular prostheses
3. Terminology
may be evaluated for additional failure mechanisms including
separation, loosening, fracture, and deformation of any com-
3.1 Definitions:
ponent or locking mechanism, or both.
3.1.1 component separation—the disruption of a connection
between components. May be stable or unstable.
4.2 This test method may be used to evaluate static or
dynamic characteristics. Various joint reaction forces and
impingements may be applied in order to simulate known
1 clinical conditions.
This test method is under the jurisdiction ofASTM Committee F04 on Medical
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.22 on Arthroplasty.
5. Significance and Use
Current edition approved June 1, 2008. Published July 2008. DOI: 10.1520/
F2582-08.
5.1 The test method may be used to evaluate and compare
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
acetabular prostheses to assess the relative degree of constraint
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
for the prosthesis and the damage tolerance under controlled
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. laboratory conditions.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2582 − 08
FIG. 1 Representative Unconstrained Planar Bearing Fixture for
Femoral Component
FIG. 4 An Example Test Setup
FIG. 5 An Example Test Setup Showing the Point of Impingement
FIG. 2 Schematic Representation of the Test Setup
FIG. 6 Representative Moment versus Angular Displacement Re-
sult Obtained for the Static ROM and Dislocation Test
6. Apparatus
FIG. 3 Schematic Representation of the Test Setup at the Point
6.1 One axis must be capable of applying either a constant
of Impingement
joint reaction force for static and dynamic loading or a
physiological waveform for dynamic loading.
5.2 It is recognized that there are several clinical failure
modes for acetabular prostheses and that this test method may 6.2 A second axis must be capable of controlling and
or may not be capable of reproducing them. monitoring angular displacement and torque.
F2582 − 08
The variation in geometry of any single prosthesis may be evaluated by
6.3 The equipment may be electromechanical, servo-
choosing different orientations for the initial positioning of the prosthesis
hydraulic or other, as long as it meets the requirements of
and then repeating the measurement procedure. Physiologically relevant
Practices E4 and E467 for force verification.
positions may be tested by changing the position of the acetabular cup.A
typical position would place the acetabular component at an angle to
6.4 The joint reaction force must be applied through uncon-
replicate a 45° superior inclination while measuring ROM and dislocation
strained fixturing that allows for the separation of the acetabu-
events during rotation that simulates a flexion/extension action of the
lar prosthesis from the femoral prosthesis during the impinge-
femoral component.
ment and dislocation test. See Fig. 1 for representative fixture.
NOTE 2—Computer models may be used to evaluate the range of
See Fig. 2 for the test set-up. motion of acetabular prostheses.
8.1.7 The dislocation moment may be measured by continu-
7. Sampling and Test Specimens
ing the angular displacement beyond impingement until dislo-
7.1 All acetabular and femoral head components shall be cation occurs.
representative of implant quality products. This shall include
NOTE3—Theangulardisplacementratemaybeadjustedtosimulatethe
any sterilization processes if the sterilization may affect the
intended cyclic test rate.
results.
8.1.8 Measure the dislocation moment with an apparatus
7.2 Femoral neck components shall have geometries repre-
that has an accuracy of at least 0.2 N-m.
sentative of finished product but may be manufactured from
8.1.9 Continuously record torque and displacement data at a
non-implant grade materials.
sufficient rate to capture the peak moment and provide a graph
of moment versus angular displacement (see Fig. 6).
7.3 Aminimum of five assemblies shall be tested under any
set of boundary conditions chosen to determine the static range
8.2 Unidirectional Dynamic Impingement Testing:
of motion and dislocation moment.
8.2.1 This method may be used for the unidirectional cyclic
or dynamic evaluation of acetabular prostheses with the
7.4 Multiple tests may be performed on each specimen.The
following considerations.
appropriateness of performing multiple tests on the same
8.2.2 An environment of water at 37 6 2°C shall be used to
components will depend on the type of testing and will require
provide lubrication and temperature control during the test.
careful monitoring and reporting of component properties.
8.2.3 A constant joint reaction force of 1000 N is recom-
7.5 Precondition the specimens for 24 h in the laboratory
mended. Higher forces may be used.
test environment, for example 25 6 3°C and 50 6 10 %
8.2.4 Apply a moment of 10 N-m or 70 % of the peak
relative humidity (RH).
dislocationmoment(seeFig.6)measuredstatically(whichever
7.6 Precondition the specimens for 48 h in the test environ-
is less) using a sinusoidal forcing function with R = 0.3.
ment if this is water at 37 6 2°C.
8.2.5 Test for a maximum of one million cycles or failure,
whichever comes first. Failure is defined in 8.4.
8. Procedure
8.2.6 The maximum test frequency shall be 10 Hz.
8.1 Static Range of Motion (ROM) and Dislocation Testing:
8.3 Bi-directional Dynamic Impingement Testing:
8.1.1 See Fig. 2 for a schematic representation of the test
8.3.1 Impingement testing may be controlled with a sinu-
setup. See Figs. 4 and 5 for an example setup for testing.
soidal forcing function ranging from +10 N-m to –10 N-m or
8.1.2 Mount a femoral head assembly on the main joint
...
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