ASTM F451-99a(2007)e1
(Specification)Standard Specification for Acrylic Bone Cement
Standard Specification for Acrylic Bone Cement
SCOPE
1.1 This specification covers self-curing resins used primarily for the fixation of internal orthopedic prostheses. The mixture may be used in either the predough or dough stage in accordance with the manufacturer's recommendations.
1.2 Units of premeasured powder and liquid are supplied in a form suitable for mixing. The mixture then sets in place.
1.3 While a variety of copolymers and comonomers may be incorporated, the composition of the set cement shall contain poly(methacrylic acid esters) as its main ingredient.
1.4 This specification covers compositional, physical performance, and biocompatibility as well as packaging requirements. The biocompatibility of acrylic bone cement as it has been traditionally formulated and used has been reported in the literature (1, 2).
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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Designation: F 451 – 99a (Reapproved 2007)
Standard Specification for
Acrylic Bone Cement
This standard is issued under the fixed designation F 451; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Sections 7.9.2.1 and X1.1 were editorially corrected in December 2007.
1. Scope F 748 Practice for Selecting Generic Biological Test Meth-
ods for Materials and Devices
1.1 This specification covers self-curing resins used prima-
F 749 Practice for Evaluating Material Extracts by Intracu-
rily for the fixation of internal orthopedic prostheses. The
taneous Injection in the Rabbit
mixture may be used in either the predough or dough stage in
F 756 Practice for Assessment of Hemolytic Properties of
accordance with the manufacturer’s recommendations.
Materials
1.2 Units of premeasured powder and liquid are supplied in
F 763 Practice for Short-Term Screening of Implant Mate-
a form suitable for mixing. The mixture then sets in place.
rials
1.3 While a variety of copolymers and comonomers may be
F 813 PracticeforDirectContactCellCultureEvaluationof
incorporated, the composition of the set cement shall contain
Materials for Medical Devices
poly(methacrylic acid esters) as its main ingredient.
F 895 Test Method forAgar Diffusion Cell Culture Screen-
1.4 This specification covers compositional, physical per-
ing for Cytotoxicity
formance, and biocompatibility as well as packaging require-
F 981 Practice for Assessment of Compatibility of Bioma-
ments. The biocompatibility of acrylic bone cement as it has
terials for Surgical Implants with Respect to Effect of
been traditionally formulated and used has been reported in the
Materials on Muscle and Bone
literature (1, 2).
2.2 ANSI/ADA Standard:
1.5 This standard does not purport to address all of the
No. 15 Specification for Acrylic Resin Teeth
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety and health practices and determine the applica-
3.1 Definitions of Terms Specific to This Standard:
bility of regulatory limitations prior to use.
3.1.1 doughing time—the time after commencement of
2. Referenced Documents mixing at which the mixture ceases to adhere to a standard
probe (see 7.5).
2.1 ASTM Standards:
3.1.2 exothermic or maximum temperature—the maximum
D 695 Test Method for Compressive Properties of Rigid
temperature of the mixture due to self-curing in a standard
Plastics
mold (see 7.6).
D 3835 Test Method for Determination of Properties of
3.1.3 extrusion—the rate of flow of the material through a
Polymeric Materials by Means of a Capillary Rheometer
standard orifice under load (see 7.8.1).
E 29 Practice for Using Significant Digits in Test Data to
3.1.4 intrusion—the distance of flow of the mixture into a
Determine Conformance with Specifications
standard mold under load (see 7.8.2).
E 141 Practice for Acceptance of Evidence Based on the
3.1.5 setting time—the time after commencement of mixing
Results of Probability Sampling
at which the temperature of the curing mass equals the average
F 619 Practice for Extraction of Medical Plastics
of the maximum and ambient temperatures (see 7.7).
3.1.6 unit—one package or vial of premeasured powder
1 component and one package or vial of premeasured liquid
This specification is under the jurisdiction of ASTM Committee F04 on
component.
Medical and Surgical Materials and Devices and is the direct responsibility of
Subcommittee F04.11 on Polymeric Materials.
Current edition approved Dec. 1, 2007. Published January 2008. Originally
4. Physical Requirements
e1
approved in 1976. Last previous edition approved in 1999 as F 451 – 99a .
2 4.1 Liquid:
The boldface numbers in parentheses refer to the list of references at the end of
this standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F 451 – 99a (2007)
TABLE 2 Requirements for Cured Polymer After Setting
4.1.1 Appearance—The liquid shall be free of extraneous
particulate matter or obvious visual contaminants in its con- Property Requirement
tainer.
Compressive Strength, min., MPa 70
4.1.2 Stability—Afterbeingheatedfor48hat60 62°C,the
viscosity of the liquid shall not increase by more than 10 % of
7. Test Methods and Sample Size
its original value (see 7.3).
4.1.3 Sterility—The liquid, as poured from its container, 7.1 Maintain all equipment, mixing surfaces, and materials
shall pass the tests described in “Sterility Tests—Liquid and
at 23 6 2°C at least 2 h prior to testing and conduct all tests at
Ointments” (7.4) (3). 23 6 2°C and 50 6 10 % relative humidity unless otherwise
4.2 Powder: specified.
4.2.1 Appearance—The powder shall be pourable and free 7.2 Inspection—Use visual inspection in determining com-
of extraneous materials, such as dirt or lint (7.2.2). pliancetotherequirementsoutlinedin4.1.1,4.2.1,8.1and8.2.
7.2.1 The liquid component of two separate units shall
4.2.2 Sterility—The powder, as poured from its package,
shall pass the tests described in “Sterility Tests—Solids” (7.4) comply with the requirements of 4.1.1 and 8.1.
(2). 7.2.2 The powder component of two separate units shall
4.3 Powder-Liquid Mixture: comply with the requirements of 4.2.1 and 8.1.
7.3 Liquid Component Viscosity—Record the viscosity
4.3.1 If the mixture is to be used in its predough stage, the
material shall conform to the properties given in Table 1. change of two separate units (4.1.2) before and after the
heatingexposurebytimingtheflowoftheliquidlevelbetween
4.3.2 If the mixture is to be used in its dough stage, the
the 0 and 5 mL marks of a 10 mL measuring pipet. Calculate
material shall conform to the properties given in Table 1.
the percent change as follows:
4.3.3 If the mixture can be used in either its predough or
doughstages,separateunitsmustbetestedforcompliancewith
t 2 t
a b
% Change 5 3 100 (1)
4.3.1 and 4.3.2.
t
b
4.4 Cured Polymer—The material after setting shall con-
where:
form to the properties given in Table 2.
t = flow time before heating, and
b
t = flow time after heating exposure (4.1.2)of60 6 2°C
a
5. Weights and Permissible Variations
for 48 h in the dark in a closed container.
5.1 Weight and volume measurements shall be made on the
7.3.1 An alternative method for viscosity may be used if it
respective powder and liquid components of five units (see
can be demonstrated to yield similar results. Both shall comply
3.1). These units may be subsequently utilized in any of the
to the less than 10 % change specified (4.1.2).
nonsterile tests of this specification.
7.4 The components of the two units shall be tested for
5.2 The weights, or volume of the powder and liquid
sterility in accordance with the test methods described in U.S.
components, or both, shall not deviate by more than 5 % from
Pharmacopoeia,“ Sterility Tests” (3).
those stated on the package (9.2.2), of each of five units.
7.5 Doughing Time:
5.3 Where a radiopaque material is supplied for addition to
7.5.1 Environment—All equipment, mixing surfaces, and
the powder at the discretion of the surgeon, the weight or
material (unit size) shall be maintained at 23 6 1°C at least 2
volume percent of the radiopaque material shall not deviate by
h prior to testing and tests shall be conducted at 23 6 1°C.The
more than 15 % from the value stated on the package (9.2.3).
relative humidity shall be 50 6 10 %.
7.5.2 Mix all the powder and liquid of a single unit together
6. Sampling
as directed by the manufacturer’s instructions (see 8.2). Start a
stop watch at the onset of combining the liquid to the powder
6.1 Units of powder and liquid shall be procured to provide
and read all subsequent times from this stop watch. Approxi-
sufficient material for all the tests of this specification. The
mately 1.5 min after the onset of mixing, gently probe the
unitsshallbeobtainedfromregularretaildistributionchannels.
mixture with a non-powdered surgically gloved (latex) finger.
Provided no repeat tests are required, this will amount to
Take visual notice as to the formation of fibers between the
between seven and ten units.
surfaceofthemixandthefingerasitleavesthesurface.Repeat
6.2 It will only be necessary to maintain sterility in tests
this process from that time on at 15 s intervals with a clean
described in 7.4. All other tests described in this specification
portion of the glove until the gloved finger separates cleanly.
need not be conducted under sterile conditions.
Denote the time at which this is first observed as the doughing
time. Mix the mixture between determinations to expose fresh
material for each probing.
TABLE 1 Requirements for Powder Liquid Mixture
7.5.3 Determine the average doughing time from two sepa-
Dough Usage,
Extrusion,
rate units.
Property Intrusion
Viscosity Tests
Tests
7.5.4 The two values found shall agree within 30 s of each
Max Dough Time, min. 5.0 5.0 other, otherwise repeat the test on two additional units. Report
Setting Time Range, min. 5 to 15 5 to 15
the average of all four tests and the range of values.
Temperature, max., °C 90 90
7.5.5 Report the doughing time to the nearest 15 s as the
Intrusion, min., mm . 2.0
average of all determinations. Maximum and minimum values
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F 451 – 99a (2007)
ofdoughingtimesmeasuredshallnotdifferbymorethan 61 ⁄2 7.6.1 Themaximumtemperatureshallbetheaverageoftwo
min from the average. separate determinations reported to the nearest 1°C.
7.6 Exothermic Temperature—Within 1 min after doughing
7.6.2 If the difference between the maximum temperature
time,gentlypackapproximately25gofthedoughdescribedin
for the two determinations is greater than 5.0°C, repeat the test
7.5 into the mold described in Fig. 1. This mold shall be made
on two additional units and report the average of all four runs
of polytetrafluoroethylene (PTFE), poly(ethyleneterephtha-
to the nearest 1°C. Individual maximum and minimum values
late), polyoxymethylene, high density polyethylene, or ultra-
for maximum temperature shall not differ by more than 64°C
high molecular weight polyethylene (UHMWPE) and be
of the average value of all determinations.
equipped with a No. 24 gage wire thermocouple, or similar
7.7 Setting Time—From the continuous time versus tem-
device, positioned with its junction in the center of the mold at
perature recording of 7.6, the setting time (T ) is the time
set
a height of 3.0 mm in the internal cavity. Immediately seat the
when the temperature of the polymerizing mass is as follows:
plungerwithaC-clamporsuitablepresstoproducethe6.0mm
specimen height. Upon producing plunger seating, remove the ~T 1 T !/2 (2)
max amb
excess material and the C-clamp or press for the remainder of
where:
the procedure. Continuously record the temperature with re-
T = maximum temperature, °C, and
max
spect to time from the onset of mixing the liquid and the
T = ambient temperature of 23 6 1°C.
amb
powder until cooling is observed, Fig. 2. Report the maximum
7.7.1 Report the setting time to the nearest 5 s.
temperature recorded to the nearest 1°C. This should not
exceed the value given in Table 1. 7.7.2 Make two separate determinations of the setting time.
NOTE 1—Dimensions in millimetres and 60.2 unless otherwise specified. Material for all components: Polytetrafluoroethylene, poly(ethylenetereph-
thalate), polyoxymethylene, high density polyethylene, or ultra-high molecular weight polyethylene (UHMWPE).
FIG. 1 Exothermic Heat Mold
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F 451 – 99a (2007)
FIG. 2 Continuous Temperature Record
7.7.3 The two values should agree within 1 min of each thestandardfluidandthepercenterrorfromitsspecifiedvalue.
other, otherwise repeat the test on two additional units and Report this error along with the viscosity of the tested cements.
report the average of all runs. 7.8.1.3 Corrections— Since bone cement is a non-
7.7.4 Report the setting time to the nearest 15 s as the
Newtonian fluid, the data may be reported as corrected data.
average of all determinations.
For example, true shear rates, corrected for non-Newtonian
7.8 Flow Properties and Viscosity Determination—The
flow behavior and true shear stress corrected for end effects or
manufacturer must specify whether the cement may be used in
kinetic energy losses, may be calculated. In such cases, the
its pre-dough or dough state, or both. The determination of its
exact details of the mode of correction must be reported. Some
usage dictates which of the following tests the cement should
correction factors which may apply are:
comply with. If the mixture is to be utilized in the pre-dough
(1) Piston friction,
stage,usetheextrusion,viscositytest(7.8.1)andTable1.Ifthe
(2) Plunger back flow,
mixture is to be utilized in the dough stage, use the intrusion
(3) Cement compressibility,
test (7.8.2) and Table 1. If the mixture is to be used as a dual
(4) Barrel back pressure,
usage cement, then both the extrusion (7.8.1) and intrusion
(5) Capillary entrance effects (Bagley correction) (6),
(7.8.2) tests must be performed.
(6) Rabinowitsch shear rate correction (7).
7.8.1 Extrusion, Viscosity:
7.8.2 Procedure:
7.8.1.1 Apparatus:
7.8.2.1 Select conditions of temperature and shear stress or
7.8.1.1.1 Rheometer—Any capillary rheometer is satisfac-
shear rate in accordance with expected usage so that the flow
tory in which acrylic bone cement can be forced from a
rate will fall within desired limits.
reservoir through a capillary die and in which temperature,
7.8.2.2 Inspect the rheometer and clean it if necessary.
appliedforce,outputrate,andbarrelanddiedimensionscanbe
Ensure that previous cleaning procedures and usage have not
controlled and measured accurately. Equipment that provides a
changed the dimensions or caused scratches or defects in the
constant shear rate has been shown to be equally useful. The
capillary or apparatus. Make the necessary measurements on
capillary die of the rheometer shall have a smooth straight bore
the apparatus for future calculations. Prepare the apparatus for
that is held within 60.0076 mm (60.0003 in.) in diameter and
running
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