U.S. patent number 3,924,275 [Application Number 05/466,640] was granted by the patent office on 1975-12-09 for artifical joint prosthesis using al.sub.2 o.sub.3 material.
This patent grant is currently assigned to Friedrichsfeld GmbH Steinzeug-und Kunststoffwerke. Invention is credited to Peter Griss, Gunther Heimke, Hanns Frhr. VON Andrian-Werburg.
United States Patent |
3,924,275 |
Heimke , et al. |
December 9, 1975 |
Artifical joint prosthesis using Al.sub.2 O.sub.3 material
Abstract
Prosthesis made of biologically compatible material, such as
Al.sub.2 O.sub.3, can be directly implanted in bone tissue without
cement and without biologically deleterious effects. At least one
surface is provided by means of which the load forces are
transmitted directly between the prosthesis and the bone tissues. A
socket may be polygonally shaped, or may be cylindrical with a
helically exterior screw thread. Exterior grooves are provided,
into which bone tissue grows to firmly bond the prosthesis in place
and means is provided to prevent rotation prior to bone tissue
growth.
Inventors: |
Heimke; Gunther (Mannheim,
DT), Griss; Peter (Plankstadt, DT), VON
Andrian-Werburg; Hanns Frhr. (Ilvesheim, DT) |
Assignee: |
Friedrichsfeld GmbH Steinzeug-und
Kunststoffwerke (Mannheim, DT)
|
Family
ID: |
25765155 |
Appl.
No.: |
05/466,640 |
Filed: |
May 3, 1974 |
Foreign Application Priority Data
|
|
|
|
|
May 17, 1973 [DT] |
|
|
2324865 |
May 19, 1973 [DT] |
|
|
2325585 |
|
Current U.S.
Class: |
623/22.31;
606/76 |
Current CPC
Class: |
A61F
2/34 (20130101); A61F 2/30907 (20130101); A61F
2/36 (20130101); A61F 2002/30823 (20130101); A61F
2310/00203 (20130101); A61F 2230/0026 (20130101); A61F
2/3609 (20130101); A61F 2310/00017 (20130101); A61F
2002/3085 (20130101); A61F 2002/30158 (20130101); A61F
2002/30929 (20130101); A61L 2430/24 (20130101); A61F
2310/00592 (20130101); A61F 2002/3631 (20130101); A61F
2310/00934 (20130101); A61F 2002/3403 (20130101); A61F
2310/00928 (20130101); A61F 2/32 (20130101); A61F
2002/365 (20130101) |
Current International
Class: |
A61F
2/32 (20060101); A61F 2/30 (20060101); A61F
2/34 (20060101); A61F 2/38 (20060101); A61F
2/36 (20060101); A61F 2/00 (20060101); A61F
001/24 () |
Field of
Search: |
;3/1,1.9-1.913
;128/92C,92CA,92R,92BC |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2,096,895 |
|
Mar 1972 |
|
FR |
|
426,096 |
|
Jun 1967 |
|
CH |
|
1,047,640 |
|
Jul 1953 |
|
FR |
|
Other References
"Replacement of Arthritic Hips by the McKee-Farrar Prosthesis" by
G. K. McKee et al., The Journal of Bone & Joint Surgery, Vol.
48 B, No. 2, pp. 245 & 246, May 1966. .
"The Trapezoidal 28 from Zimmer USA" (Advertisement) 3 pages relied
upon - The Journal of Bone & Joint Surgery, Vol. 55-A, No. 3,
Apr. 1973. .
"F. R. Thompson Hip Prosthesis Vitallium Surgical Appliances,
(catalog), Austenal Medical Div. Howmet Corp., New York, N.Y.,
1964, pp. 23-24..
|
Primary Examiner: Frinks; Ronald L.
Claims
We claim:
1. A socket for hip joint prostheses for cement-free implantation
in bone tissue, comprising a biologically compatible material such
as compacted Al.sub.2 O.sub.3 ceramic, said socket being provided
with an internal hemispherical cavity, an exterior upper load
bearing surface portion of the socket being provided with at least
one elongated groove to provide a direct physical connection with
bone tissue grown after implantation and an exterior surface
portion including means to prevent rotation of the socket directly
after implantation, the overall height of the socket being less
than the diameter of the hemispherical cavity, the transverse
dimensions of the upper portions of the socket being less than the
largest diameter of the socket but, larger than the diameter of the
hemispherical cavity.
2. The invention defined in claim 1, wherein the upper exterior
surface of said socket is provided with at least one groove having
an undercut transverse profile to receive bone tissue grown after
implantation.
3. The invention defined in claim 1, wherein an upper exterior
surface of said socket is defined by a cylinder of revolution, and
said elongated groove comprises a helical thread provided in said
exterior surface.
4. The invention defined in claim 3, wherein the transverse profile
of said thread includes one face disposed generally normal to the
direction of the force of the load to be supported by the
socket.
5. The invention defined in claim 3, wherein said means to prevent
rotation comprises at least one elongated groove provided in said
upper surface, and transversely intersecting at least some of the
turns of said thread.
6. The invention defined in claim 3, wherein said socket is
provided with a bore extending between the interior of the cavity
and the upper exterior surface of the socket.
7. The invention defined in claim 3, wherein said socket includes
an annular flange flaring outwardly from the hemispherical
cavity.
8. The invention defined in claim 7, wherein said means to prevent
rotation comprises a peg to be inserted in an axial direction
through an opening provided in said annular flange and the bone
tissue in alignment therewith.
9. The invention defined in claim 7, wherein the transverse profile
of said elongated groove intersecting said threads is defined by a
semi-cylindrical surface in axial alignment with said opening in
the annular flange.
10. A socket for hip joint prostheses for cement-free implantation
in bone tissue, comprising a biologically compatible material such
as compacted Al.sub.2 O.sub.3 ceramic, said socket being provided
with an internal hemispherical cavity, an exterior upper load
bearing surface portion of the socket being provided with at least
one elongated groove to provide a direct physical connection with
bone tissue grown after implantation and an exterior surface
portion including means to prevent rotation of the socket directly
after implantation, the overall height of the socket being less
than the diameter of the hemispherical cavity, the transverse
dimensions of the upper portions of the socket being at least
substantially equal to the largest diameter of the socket and
larger than the diameter of the hemispherical cavity, the exterior
side surface of at least the upper portion of said socket being
defined by a series of intersecting planes.
11. The invention defined in claim 10, wherein a lower portion of
the exterior surface of the socket is defined by a plane
intersecting an adjacent pair of said first mentioned planes and
angularly related thereto.
12. The invention defined in claim 10, wherein said intersecting
planes define a regular polygon.
13. The invention defined in claim 12, wherein said regular polygon
has four sides.
14. The invention defined in claim 13, wherein a lower portion of
the exterior surface is defined by a plane intersecting an adjacent
pair of said first mentioned planes and angularly related thereto.
Description
The invention relates to a socket for a hip joint prosthesis of
ceramic material for implantation without cement.
The hip joint prostheses used hitherto generally consist of plastic
sockets and a metal part for the replacement of the head of the
femur, or of metal sockets and a plastic part as a replacement of
the head of the femur. These parts and especially the sockets,
hitherto were mostly anchored and fixed in the hip bone with bone
cement.
Hip joint prostheses made of ceramic, especially of a compact
aluminum-oxide-ceramic, have also been proposed already. These
ceramic prostheses have the advantage, as compared to the metal and
metal-plastic combination prostheses, that the friction, gliding
and wear characteristics of ceramic, especially of aluminum oxide
ceramic, are much superior to those of the metals and plastics.
Moreover the ceramic has a much better body compatibility than
plastics and metals.
In order to be able to utilize this greater body compatibility of
the ceramic implants, it is however necessary, to implant and
secure them without the use of plastic cements. The sockets of hip
joint prostheses used hitherto for implantation without cement,
consisted essentially in imitations of the socket shapes, which had
been known from plastic socket constructions. The surface facing
the bone, was generally essentially hemispherical or cup shaped and
had grooved patterns of various kinds. The disadvantage of this
construction consisted in the fact that for a firm anchoring in the
bone, either complicated puncture patterns had to be chiselled into
the hip bone, or else the growing of bone into the grooved
structure took some time, so that patients were exposed to a
relatively long period of immobilization. This is however
undersirable because of the danger of thrombosis.
In the case of the metal sockets for hip joint prostheses, a
screw-type fastening is already known. (Total endoprosthesis
according to Ring). In the case of this construction, however, the
overall height amounts to several times the diameter of the socket,
the diameter of the thread is considerably smaller than the
diameter of the hemispherical cavity of the socket. This
construction however, can not be used for a ceramic socket,
especially one of compacted aluminum-oxide-ceramic, since it does
not take into consideration the material characteristics of ceramic
and since there would be the danger of breaking of the long screw
during fastening.
According to the present invention, the construction described in
the following pages in more detail, and which at the same time has
a number of advantages, is provided for the socket of hip joint
prostheses made of aluminum-oxide-ceramic. It has been discovered
that the socket of the invention will permit a load to be applied,
even in case of cement-free implantation, very soon after the
operation and nevertheless grows very firmly into the body even in
the succeeding period, while under strain, and is completely
integrated into the bone connection mechanism.
Sockets made of various metal alloys for cement-free implantation
have also been proposed already. Screws or else long pegs served
for their attachment, which are screwed or driven into the adjacent
bone space.
However it turned out that the bio tolerance of plastic cements,
plastics and metals is not very favorable. Therefore, the danger
exists of a loosening of the socket after the cemented-in socket
has remained in the body for some time. This danger of loosening is
particularly great in case of the metallic sockets implanted
without cement.
For some time it has been known, that certain types of ceramic and
a few types of glass ceramic have a considerably more favorable
body compatibility as compared to metals and plastics. This is
particularly true for Al.sub.2 O.sub.3 ceramic, whereby we
understand by Al.sub.2 O.sub.3 ceramic, a ceramic which contains
95% aluminum-oxide or more, especially 99% Al.sub.2 O.sub.3.
Extensive animal experiments and first results of cement-free
implantations of parts of joint prostheses made of compact Al.sub.2
O.sub.3 ceramic, show that a firm anchoring of such parts without
the help of cement is possible. In case of favorable conditions,
for example, after an immobilization of the respective joint for a
few weeks to months, a mechanically very strong connection develops
between the implant and the surrounding bone tissue.
For the cement-free implantation of hip joint sockets for total
prostheses made of Al.sub.2 O.sub.3 ceramic, sockets of various
other shapes have also been proposed and used already; one socket
construction of this type has at its rear an essentially
hemispherical shape, into which deep grooves have been worked in.
It carries a peg at its crest, which is round and which likewise
has deep grooves. This socket construction is similar to known
sockets made of plastic and, in case of cement-free implantation,
it has the disadvantage that there is no genuine protection against
twisting. Until such time that the tissue has grown firmly to the
surface, or the bone tissue has grown into the grooves and
channels, there exists the danger of twisting of this type of
socket in case of even slight movement in the joint, as a result of
which this growing-in, or -on, can be delayed or even
prevented.
One form of socket for total hip joint prostheses made of Al.sub.2
O.sub.3 ceramic, according to the invention for cement-free
implantation, has an angular shaped rear portion. It can be
triangular, square, pentagonal or hexagonal. This angular rear
portion is provided with grooves and channels, a part of which can
also have some dovetailed or similar reverse tapering, and can grow
into the bone tissues for a better anchoring of the socket.
The invention also relates to the thigh part of a total hip joint
prosthesis for the cement-free implantation, especially prostheses
consisting of Al.sub.2 O.sub.3 ceramic and prostheses made of a
combination of a ceramic head with a metal shaft, in which case,
the metal shaft is covered with a vitreous material such as a
glaze, enamel or a glass ceramic, as described and claimed in the
copending application of Gunther F. A. Heimke and Peter Griss, Ser.
No. 440,444, filed Feb. 7, 1974, corresponding to German
Application No. P 23 06 552.3.
The thigh parts of total hip joint prostheses are attached, at
present, mostly by means of plastic cement in the marrow space of
the femur. These prostheses consist of metal alloys, the
composition of which is selected such that they will show the least
possible corrosion phenomena in a biological environment. The
transfer of a load from the thigh prosthesis to the femur takes
place in the case of these prostheses essentially by the
intermediation of the bone cement, which in its plastic state,
closely follows the inside contour of the femur. During shaping the
shaft of a metal thigh prosthesis for implantation with the aid of
bone cement, no special attention need be given to the load
transfer from the prosthesis to the femur. Since this part of the
prosthesis is surrounded entirely by bone cement, aspects of tissue
tolerance and avoiding of movements between bone tissue and the
implant are of no consequence during shaping of said part.
Therefore, in case of the metal prostheses for implantation with
plastic cements, one needs to consider only mechanical aspects for
the shaping of the shaft of the prosthesis.
Prior to the general introduction of bone cements for the
attachment of joint prostheses in the adjacent bone space, it was
also customary to introduce or drive into the marrow space of the
femur thigh parts of hip joint prostheses even without bone cement.
This method of attachment however, was unsatisfactory. In many
cases these parts of prostheses sunk deeper and deeper into the
femur, since the bone decomposed in areas where the load was too
high. In many other cases, the prosthesis became loose after a
time, since a firm connection between the shaft of the prosthesis
and the bone tissue did not occur because of the unfavorable
biological tolerance of the metals.
Because certain types of ceramic, for example compacted Al.sub.2
O.sub.3 ceramic with 99% Al.sub.2 O.sub.3 content, as well as
certain glass ceramics have an excellent tissue compatibility,
especially in regard to bone tissue, it has been found that under
certain conditions, a mechanically firm connection between the
surfaces of such implants and the bone tissue develops.
This now results in the possibility of anchoring the thigh parts of
total hip joint prostheses without cement and mechanically solidly
in the marrow space of the femur. This cement-free implantation is
very desirable, since the plastic bone cements available hitherto
had many and serious drawbacks.
However, up to now there did not exist any prosthesis constructions
for this cement-free implantation, in the case of which the
introduction of the load from the implant into the femur is
accomplished in such a way, that bending and tension strains in the
adjacent surfaces between the implant and the bone are avoided as
much as possible, and high pressure loads are eliminated. In the
case of the use of total ceramic prostheses, one must naturally
also take the characteristics of compact Al.sub.2 O.sub.3 --
ceramic into consideration.
Other objects and advantages will be apparent to those skilled in
the art by reading the following specification in connection with
the annexed drawings, in which;
FIG. 1 is a cross-section of a preferred form of hip joint socket
made in accordance with the invention;
FIG. 2 is a fragmentary cross-section of a detail of FIG. 1;
FIG. 3 is a top view of the socket;
FIG. 4 is a cross-section of a modified form of socket;
FIG. 5 is a bottom view of the socket of FIG. 4;
FIG. 6 is a top view of the socket of FIGS. 4 and 5;
FIG. 7 is a side elevation of a preferred form of the thigh portion
of the prosthesis;
FIG. 8 is a side elevation as viewed from the left of FIG. 7,
and
FIG. 9 is a cross-section on the line 9--9 of FIG. 8.
A socket made in accordance with a preferred form of the invention
made of aluminum-oxide-ceramic for implantation without cement will
be explained in more detail on the basis of FIGS. 1-3. FIG. 1 shows
a section through the socket; FIG. 2 the anchoring thread and FIG.
3, a view of the socket from above. The socket contains the
approximately hemispherical cavity 1, the surface of which is
polished and on which the spherical head, likewise polished on its
surface and consisting of the same ceramic, of the thigh element of
the hip joint prosthesis, anchored in the femur, is mounted in a
swivel-type manner. The body of the socket consists of
aluminum-oxide-ceramic 2. According to the invention, this socket
body is cylindrically-shaped in its upper part which faces the hip
bone, with a cylinder diameter D, which is smaller than the total
diameter d 1 of the socket, but larger than the diameter of the
hemispherical cavity d 2 in the inside of the socket. The overall
height h of the socket according to the invention is smaller than
the diameter of the hemispherical cavity d 2.
The cylindrical part of the socket is provided on its outside
surface with a thread 3. This thread 3 is made in such a manner
that it can transfer forces, which act from the thigh on the
socket, particularly favorably to the hip bone. These forces are,
directed from below to above in the representation shown in FIG. 1.
An example for a thread made in this way is shown in FIG. 2. On the
outside of the cylindrical part having the diameter D, axially
parallel grooves are worked in transverse to the thread. These
grooves can be of a semicircular shape for example. They are
designated by 4 in FIG. 3, which shows a view of the socket from
above. These grooves interrupt the thread, whereby it appears to be
particularly useful, to make this break as sharp-edged as possible.
In FIG. 3, four such grooves have been drawn but, their number can
also be greater or smaller than four. In the extension of these
grooves there are holes which extend through the bead-shaped part 5
of the socket up to the front side of the socket. On the topside of
the socket, that is, of the side projecting into the hip bone, a
series of grooves is provided. In FIG. 1, these grooves consist of
the dove-tailed grooves 6 and 7, which, in the view of FIG. 3, are
represented by the grooves 8. Naturally, other arrangements of the
grooves may also be selected according to the invention, but it
will be particularly useful to provide the grooves existing on the
topside with reverse-tapering, as given by the dovetail of the
grooves 6 and 7. In the middle of the socket cavity, a hole 9 is
provided.
During implantation of the socket according to the invention, for
hip joint prostheses, one proceeds as follows: first an
approximately round part is chiselled out, having a diameter which
is still noticeably smaller than the diameter of the cylindrical
part of the socket. Its depth is chiselled out to the point which
approximately corresponds to the later seat of the socket.
Subsequently, the preprocessed cavity is filed out further with a
rasp, the diameter of which, measured across the outside teeth of
the rasp, corresponds to the diameter D less twice the depth t of
the thread. In the wall of this cylindrical hole, a thread is cut
with a suitably shaped set of threading tools into the now
cylindrical wall of the bone. At the same time the threading tool
is dimensioned such that, after the last cutting process, the
thread is about 1/2 to 1mm smaller in its diameter, than would
correspond to the thread on the socket.
The grooves 6 and 7 or 8 are partly filled with the bone ships
produced during the chiselling out of this cavity. Then the socket
is moved close to pre-cut turns of the thread and is turned into
the preprocessed thread with a tool which reaches into the
continuous holes 4 or their extensions. Since the pre-cut thread
was a little smaller than corresponds to the thread of the socket,
the application of some force is necessary for this, as a result of
which, the socket thread forces itself firmly into the bone. This
"forcing into" is assisted by the four grooves 4, which cut the
thread. This assistance is the more favorable, the more sharp-edged
these breaks are, as has already been explained further back.
By this screwing in of the sockets into a somewhat smaller thread,
the socket will be firmly anchored in the hip bone immediately
after implantation. At the same time, it has been discovered to be
particularly favorable, surprisingly, that the bone particles which
were still separated during this screwing in, collect and remain in
the grooves 4. It also turns out, that these bone chips collecting
there considerably favor the growing-in of the live bone into the
spaces 4.
After screwing in of the socket, it will be desireable to drill a
hole of about half the socket height from the outside with a drill
inserted into at least one of the holes, which are located in
extensions of the grooves 4. A ceramic peg is pushed into this
hole, the outside diameter of which corresponds to the inside
diameter of these holes, and the length of which is similar to half
the height of the socket. This peg serves as an additional
protection against twisting until the socket has completely grown
in.
The hole 9 serves for one thing, for letting the air, which is
compressed during screwing in of the socket, escape, and for
another, for the improvement of the admittance of synovia into the
hemispherical cavity of the socket during subsequent use of the
joint.
The construction of the socket for hip joint prostheses made of
aluminum-oxide-ceramic, according to the invention, thus has the
advantage that it results in a firm seat of the socket in the hip
bone immediately after the implantation, so that it can withstand a
strain very soon after the operation. Beyond that, it causes an
acceleration of the growing-in process into the bone tissue,
whereby the well known stimulation of the adhesion of bone tissue
to the aluminum-oxide-ceramic will be favored additionally through
the presence of bone particles belonging to its own body, precisely
at those places where the growing together is particularly
desirable for the attachment of the prosthesis.
Another form of socket according to the invention is shown in FIGS.
4 and 5 in the form of a square socket. This socket consists of a
socket body 11, the inside of which contains the approximately
hemispherical hollow space 12, in which the complementary shaped
head of the thigh part of the total prosthesis is seated. The rear
13 of this prosthesis is made square as the top view shown in FIG.
6 shows. On the side, the socket has grooves 14. Grooves and
indentations are also worked into the rear, which are designated by
15 and 16 in FIG. 6. Part of these grooves in FIGS. 4 and 6, the
grooves designated by 16, have reverse tapers. Such grooves,
channels or other indentations serve for the purpose of anchoring
the socket firmly by means of growing-in tissue in the adjacent
bone space. These grooves, channels and indentations can be filled
with bone chips from the same patient during the operation and
prior to the insertion of the socket in the hip bone.
Various polygonal configurations for the socket body can be used,
but in case of square, pentagonal or hexagonal sockets, at least
one corner on the front of the socket may be bevelled in order to
avoid a chafing of the "iliopsoas." This bevelling is designated by
17 in the lower part of FIG. 5 for a square socket.
The socket according to this modification of the invention, has the
advantage, as compared to hitherto known sockets made of Al.sub.2
O.sub.3 ceramic, that it can be inserted without a special set of
instruments. The space needed for the socket in the hip bone, can
be worked out and prepared with the instruments customary in
orthopedic surgery. Implantations of sockets of this type into
large animals, such as sheep, have shown that these sockets have
such a firm seat immediately after implantation, that they will not
become loose even in the case of an immediate load on the joint,
but that a mechanically firm connection develops with the
surrounding bone tissue.
A preferred form of construction for the thigh part of a hip joint
prosthesis is shown in FIGS. 7-9, in which the prosthesis is made
of compacted Al.sub.2 O.sub.3 ceramic. It consists of the spherical
head 21, the transition part 22 with the collar 23 and the shaft
24. FIG. 8 shows a view of the same prosthesis viewed from the side
of the center of curvature p of the shaft 24. The prosthesis is
supported by the surface, designated by 25, and with the fillet
there on the front side of the wall of the femur. It is favorable
to make this surface 25 as broad as possible, in order to avoid any
increase in pressure during introduction of the load from the
prosthesis to the femur. The corresponding surface on the reverse
side 26; the side facing away from the center of curvature of the
shaft of the prosthesis, merely has to have the width which is
required for reasons of strength. The widths of the shaft of the
prosthesis at its upper end at the point where it joins surfaces 25
and 26, should therefore either be the same on both sides, or else
the width on side 25; on the side facing the center of curvature,
should be larger than on side 26, which is the side facing away
from the center of curvature. At the same time, experience shows it
to be particularly advantageous to select the width on the side of
the shaft of the prosthesis, facing the center of curvature, to be
no smaller than 10mm. According to the invention, the downward
tapering of the shaft of the prosthesis is accomplished in such a
manner, that the width on the side facing the center p of the
curvature decreases more rapidly than on the side facing away from
said center of curvature. In the lower part of the shaft, about at
the level 27 of the FIG. 8, the width on the inside, that is, on
the side facing the center of curvature, is smaller than on the
outside of the shaft facing away from the center of curvature.
Here, the width on the inside can amount to between 5 and 7mm and,
on the outside, to between 8 and 9mm. The ratio between the inside
and outside widths at the upper end of the shaft should be about
1.0 to 1.0. At the lower part of the shaft of the prosthesis, the
ratio should however, be at the most 0.9 to 1.0.
In animal experiments and in experiments where the load
transmission ratios were simulated as they exist in the human body,
it turned out that prostheses according to the invention, are
capable of bearing the usual overall loads without, at the same
time, incurring pressures at any places which are higher than those
corresponding to the pressure load in the natural bone. Thus, in
the case of use of the prosthesis according to the invention, there
is no danger of degeneration of the bone as a result of pressure
necrosis.
As in the case of the sockets made of Al.sub.2 O.sub.3 ceramic, the
shaft of the thigh portion of the prosthesis made from this
material will, over a period of time, become securely fixed within
the femur due to the affinity of this ceramic for the growing
tissues, and because the ceramic is biologically compatible with
these tissues.
* * * * *