U.S. patent number 3,687,135 [Application Number 04/858,149] was granted by the patent office on 1972-08-29 for magnesium-base alloy for use in bone surgery.
Invention is credited to Vladislav Sergeevich Borodkin, Evgeny Mikhailovich Savitsky, Konstantin Mitrofanovich Sivash, Genrikh Borisovich Stroganov, Vera Fedorovna Terekhova, Nina Mikhailovna Tikhova, Mstislav Vasilievich Volkov.
United States Patent |
3,687,135 |
Stroganov , et al. |
August 29, 1972 |
MAGNESIUM-BASE ALLOY FOR USE IN BONE SURGERY
Abstract
A magnesium-base alloy for use in bone surgery which contains
the following components, wt.%:
Inventors: |
Stroganov; Genrikh Borisovich
(Moscow, SU), Savitsky; Evgeny Mikhailovich (Moscow,
SU), Tikhova; Nina Mikhailovna (Moscow,
SU), Terekhova; Vera Fedorovna (Moscow,
SU), Volkov; Mstislav Vasilievich (Moscow,
SU), Sivash; Konstantin Mitrofanovich (Moscow,
SU), Borodkin; Vladislav Sergeevich (Moscow,
SU) |
Family
ID: |
27509491 |
Appl.
No.: |
04/858,149 |
Filed: |
September 15, 1969 |
Current U.S.
Class: |
606/76;
420/410 |
Current CPC
Class: |
C22C
23/00 (20130101); C22C 23/06 (20130101); A61L
31/022 (20130101); C22C 24/00 (20130101); C22C
25/00 (20130101); A61B 17/58 (20130101); A61L
31/148 (20130101); A61L 2430/02 (20130101); A61B
2017/00004 (20130101); A61F 2310/00041 (20130101) |
Current International
Class: |
A61B
17/58 (20060101); C22C 23/00 (20060101); C22C
23/06 (20060101); C22C 24/00 (20060101); C22C
25/00 (20060101); A61L 31/02 (20060101); A61L
31/14 (20060101); A61F 2/00 (20060101); A61B
17/00 (20060101); C22c 023/00 (); A61f
005/01 () |
Field of
Search: |
;75/168
;128/92R,92B,92BB,92BA,92BC,92C,92CA,92D ;3/1 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Annals of Surgery, Vol. 105, No. 6, June 1937, pp. 919, 920 &
938..
|
Primary Examiner: Lovell; Charles N.
Claims
We claim:
1. A bone fastening device, for the fixation of bone fragments,
constructed of an alloy, consisting essentially of, by wt.%:
2. A device as in claim 1 which has the following composition by
wt.%:
3. A device as in claim 1 which has the following composition, by
wt.%:
4. A device as in claim 1 which has the following compositions,
wt.%:
5. A device as in claim 1 which has the following composition,
wt.%:
Description
The present invention relates to magnesium-base alloys employed as
a joining and fixation material in bone surgery.
One of the main problems in the operative treatment of bone
fractures is finding a material for fixation means which is
sufficiently strong, is absorbed after the completion of union and
stimulates callus formation. The search for such a material has
been made predominantly among organic substances although there are
isolated reports of the study and use of inorganic materials,
particularly metals.
Magnesium was first employed for osteosynthesis by Lambotte in
1907. In fracture of the bones of the lower leg a magnesium plate
secured with gold-plate steel nails was used, but in 8 days the
plate disintegrated with the formation of a large amount of gas
under the skin. In spite of Lambotte's failure, study of the effect
of magnesium on the surrounding tissue and the body as a whole
continued.
An attempt to use pure magnesium for osteosynthesis was
unsuccessful because magnesium pins disintegrated so quickly that
they were unsuitable for the fixation of bone fragments;
nevertheless, clinical, X-ray and histological investigations
demonstrated that pure magnesium introduced into the body in the
form of a pin has no harmful effect.
Attempts were made to dust bone transplants with magnesium and
calcium in vacuum and then graft them in the patient's body. It was
found that magnesium and calcium promoted rapid restoration of the
entirety of the bone, this taking place 3 months sooner than when
an untreated autotransplant was employed. Said method, however, is
laborious and requires drainage for drawing off the gas formed.
Magnesium alloys with other metals have also been tried. Verbrugge
used an alloy consisting of 92 percent magnesium and 8 percent
aluminum; E. Bride reported the use of an alloy consisting of 95
percent magnesium, 4.7 percent aluminum and 0.3 percent manganese;
M.S. Znamensky used an alloy consisting of 97.3 percent magnesium,
2.5 percent aluminum and 0.2 percent beryllium; B.I. Klepatsky
tried an alloy consisting of 82.8 percent magnesium, 85 percent
aluminum, 8.5 percent zinc and 0.2 percent manganese.
A review of the literature indicates that magnesium alloys employed
for making fixation means dissolve completely in the bone and have
no detrimental effect either locally or generally. However, the
absorption of previously known magnesium alloys proceeds three or
four times more rapidly than required from the standpoint of
restoration of the entirety of the bone. Moreover, when said known
alloys are used, drainage is necessary to remove the gas
formed.
It is an object of the present invention to provide a
magnesium-base alloy which has a rate of absorption slower than the
process of bone consolidation, which does not involve vigorous
evolution of gas and which has high mechanical strength.
It is another object of the invention to provide a magnesium-base
alloy which meets the following requirements:
1. Ultimate strength .gtoreq. 28 kg/mm.sup.2 and yield point
.gtoreq. 18 kg/mm.sup.2, i.e., the alloy's mechanical strength
shall exceed that of bone tissue;
2. The rate of absorption of the alloy compared to the rate of
consolidation of the bone shall be such that at the moment of
complete restoration of the bone's entirety the alloy shall retain
sufficient strength, i.e., the process of absorption shall be
completed 1.5-2 months after knitting of the bone;
3. The rate of evolution of hydrogen during absorption of the alloy
in the body shall be less or equal to the rate of absorption of
hydrogen by the body.
4. The alloy shall contain elements which stimulate the growth of
bone tissue, such as calcium and cadmium;
5. The alloy shall not contain elements which are harmful for the
living organism, such as lead, beryllium, copper, thorium, zinc,
nickel, etc.
The foregoing objects have been accomplished by the provision of a
magnesium-base alloy which, according to the invention, contains
the following elements, wt.%:
Rare earth metal 0.40-4.0 Cadmium 0.05-1.2 Calcium or aluminum
0.05-1.0 Manganese 0.05-1.0 Silver 0-0.8 Zirconium 0-0.8 Silicon
0-0.3 Magnesium remainder
Neodymium and yttrium are predominantly employed as the rare earth
metal although other rare earth metals can be used.
The above alloy is produced by the conventional method by preparing
a charge consisting of pure metals and master alloys and melting
the same.
One of the advantages of the invention is that it provides an alloy
having high chemico-physiological, mechanical and engineering
properties. The ultimate strength of said alloy .gtoreq. 28
kg/mm.sup.2 and the yield point .gtoreq. 18 kg/mm.sup.2.
Employment of said alloy for joining bone fragments obviates the
necessity of a second operation on the patient for the removal of
foreign fastening means (pins, nails, etc.) since said alloy is
completely absorbed without the accumulation of gas. Moreover, the
stimulation of callus formation promotes the pateient's rapid
recovery.
The following examples of variations in the composition of the
alloy according to the invention are given by way of
illustration.
EXAMPLE 1
Illustrates an alloy of the following composition, wt.%:
Neodymium 2.92 Cadmium 0.27 Calcium 0.24 Manganese 0.11 Magnesium
remainder
The above alloy has the following properties:
Ultimate strength 32.6 kg/mm.sup.2 Yield point 24.5 kg/mm.sup.2
Elongation 6.3%
Said alloy was tested in a physiological solution containing 0.9
wt.% NaCl, 0.02 wt.% KCl, 0.02 wt.% CaCl.sub.2, 0.002 wt.% Na.sub.2
CO.sub.3, and the remainder, distilled water. Evolution of hydrogen
in 48 hours totalled 3.4 cm.sup.3 /cm.sup.2. The result of the test
indirectly gives a conception of the process of absorption of the
metal in the body.
EXAMPLE 2
Illustrates an alloy of the following composition, wt.%:
Neodymium 2.46 Cadmium 0.12 Aluminum 0.09 Manganese 0.14 Silicon
0.01 Magnesium remainder The above alloy has the following
properties: Ultimate strength 31.6 kg/mm.sup.2 Yield point 25.3
kg/mm.sup.2 Elongation 3.7% Hydrogen evolution in physiological
solution of Example 1, 48 hrs. 2.1 cm.sup.3 /cm.sup.2
EXAMPLE 3
Illustrates an alloy of the following composition, wt.%
Yttrium 1.6 Cadmium 0.25 Calcium 0.06 Silver 0.3 Manganese 0.08
Magnesium remainder
The above alloy has the following properties: Ultimate strength
28.4 kg/mm.sup.2 Yield point 23.6 kg/mm.sup.2 Elongation 5.5%
Hydrogen evolution in physiological solution of Example 1, 48 hrs.
1.6 cm.sup.3 /cm.sup.2
EXAMPLE 4
Illustrates an alloy of the following composition, wt.%:
Neodymium 1.8 Cadmium 0.09 Calcium 0.08 Manganese 0.13 Zirconium
0.49 Magnesium remainder
The above alloy has the following properties: Ultimate strength
32.2 kg/mm.sup.2 Yield point 21.8 kg/mm.sup.2 Elongation 8.9%
Hydrogen evolution in physiological solution of Example 1, 48 hrs.
2.0 cm.sup.3 /cm.sup.2
The properties of the above alloy were determined on specimens 0.5
mm in diameter.
Said alloys were prepared by the following method.
Charges for the preparation of alloys consisted of pure metals
(magnesium, cadmium, calcium, aluminum or silver) and master alloys
(magnesium-rare earth metal, magnesium-manganese, aluminum silicon
or magnesium-zirconium. Charges were melted in electric crucible
furnaces at a temperature of 740.degree.-780.degree. C. The order
in which the components were charged was as follows: magnesium,
master alloy, pure metals.
The charge was melted under a flux of the following composition,
wt.%:
MgCl.sub.2 34-40 KCl 25-36 NaCl + CaCl.sub.2 8.0 CaF.sub.2 15-20
MgO 7-10
after melting and thoroughly mixing, the alloy was refined with the
above flux and let stand for 15-20 minutes, after which it was
poured at a temperature of 760.degree.-780.degree. C through a
magnesite filter into moulds.
After preheating and hot pressing at 520.degree.-540.degree. C the
blanks were cooled in the air after which they were artificially
aged at 160.degree..+-.10.degree.C for 16 hours.
The alloys thus produced were ready for use. Employment of the
alloys specified in Examples 1, 2, 3 and 4 for joining bones in
bone surgery demonstrated that all of said alloys possessed high
mechanical and chemico-physiological properties. Clinical tests
showed that said alloys were completely absorbed: pins 3 mm in
diameter in 5 months and pins 8 mm in diameter in 11 months. Bones
knitted in 4 months.
Fluoroscopic examination revealed no gas bubbles in the soft
tissues during the entire period of absorption of said alloys.
Operative treatment of fractures by means of the present alloy
reduces the time required for union of the bone by 33-50 percent.
In this respect the best showing was made by the alloy described in
Example 2.
As is apparent from the figures cited, evolution of gas by the
alloys described in Examples 1, 2, 3 and 4 is within the body's
absorptive capacity, since said capacity is 4.0-4.5 cm.sup.3 of gas
from each sq.cm. of surface of the metal being absorbed per 48
hrs.
* * * * *