U.S. patent application number 10/366415 was filed with the patent office on 2003-09-25 for method and instrumentation for patello-femoral joint replacement.
Invention is credited to Abendschein, Walter F..
Application Number | 20030181984 10/366415 |
Document ID | / |
Family ID | 27734696 |
Filed Date | 2003-09-25 |
United States Patent
Application |
20030181984 |
Kind Code |
A1 |
Abendschein, Walter F. |
September 25, 2003 |
Method and instrumentation for patello-femoral joint
replacement
Abstract
A patello-femoral joint prosthesis is provided which allows
smooth tracking of the articulating surfaces through a full range
of joint motion. A novel configuration of a femoral implant
component that facilitates superior adhesion to bone is also
provided. Also provided is a patello-femoral joint replacement
system, which permits precise, reproducible bone preparation
techniques that uniquely permit later revision and full knee joint
replacement procedures with minimal complications. Also provided
are a drill guide and a cutting guide, each being configured to
provide three point stabilization during operation.
Inventors: |
Abendschein, Walter F.;
(Middleburg, VA) |
Correspondence
Address: |
Supervisor, Patent Prosecution Services
PIPER RUDNICK LLP
1200 Nineteenth Street, N.W.
Washington
DC
20036-2412
US
|
Family ID: |
27734696 |
Appl. No.: |
10/366415 |
Filed: |
February 14, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60356876 |
Feb 14, 2002 |
|
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Current U.S.
Class: |
623/20.19 ;
623/20.18; 623/908 |
Current CPC
Class: |
A61F 2002/4631 20130101;
A61F 2002/30004 20130101; A61F 2002/30807 20130101; A61F 2002/30878
20130101; A61F 2250/0014 20130101; A61B 17/1675 20130101; A61F
2/3877 20130101; A61B 2090/061 20160201; A61F 2002/30841 20130101;
A61F 2/3859 20130101; A61F 2250/0039 20130101; A61B 17/155
20130101; A61F 2/30771 20130101; A61B 17/1659 20130101; A61B
17/1764 20130101; A61F 2002/30822 20130101; A61F 2002/30891
20130101; A61F 2/30767 20130101; A61F 2002/30327 20130101 |
Class at
Publication: |
623/20.19 ;
623/20.18; 623/908 |
International
Class: |
A61F 002/38 |
Claims
What is claimed is:
1. A patello-femoral joint replacement device for implantation in a
patient in need thereof comprising: a femoral implant component,
said femoral implant comprising a bone facing surface and an upper
surface, said upper surface defining an articulating groove
disposed along the longitudinal axis of said upper surface, said
articulating groove having a distal terminus that is configured to
have a superior angled upturn, and a patellar implant component
comprising a securing surface oppositely disposed to an
articulating surface, said articulating surface being in a slidable
articulation with said articulating groove of said femoral implant,
wherein said device has full range of motion of the patello-femoral
joint.
2. The device of claim 1, wherein said femoral implant articulating
groove has a generally concave configuration longitudinally
oriented along said articulating groove and said patellar implant
articulating surface has a generally convex configuration that is
generally complementary to said articulating groove.
3. The device of claim 1, wherein said bone facing surface
comprises a circumferentially disposed undercut edge along at least
a portion of the outer most rim of the femoral implant.
4. The device of claim 1, wherein said bone facing surface
comprises at least one recessed pocket sized and configured to
receive a portion of adhesive material, said recessed pocket
providing additional surface area and improved adhesion when said
device is implanted against a bone surface.
5. The device of claim 1, wherein said femoral implant bone facing
surface comprises a roughened surface.
6. The device of claim 5, wherein said roughened surface comprises
at least one spike or peg.
7. The device of claim 5, wherein said roughened surface comprises
a porous coating.
8. The device of claim 1, wherein said securing surface of said
patellar implant comprises at least one bone anchor member, sized
and configured for insertion into a bone.
9. The device of claim 8, wherein said bone anchor member comprises
an annular retaining groove circumferentially disposed around said
bone anchor member.
10. The device of claim 8, wherein said patellar securing surface
further comprises at least one peg in addition to said bone anchor
member.
11. The device of claim 1, wherein said femoral implant bone facing
surface further comprises an intramedulary stem, said stem being
sized and configured for insertion into the femoral canal of a
patient.
12. A patello-femoral joint replacement system comprising a
patello-femoral joint replacement device, a cutting guide for
precisely guiding the use of a bone saw for cutting of the anterior
surface of a femur of a patient, and a drill guide for precisely
guiding the insertion of a bone drilling bit into the femur of a
patient.
13. The system of claim 12, further comprising a feeler gauge sized
and configured to facilitate positioning of said cutting guide so
as to accurately position a bone saw prior to the user cutting bone
therewith.
14. The system of claim 12, further comprising a bone rasp sized
and configured to be inserted into a surgical opening in a patient
undergoing patello-femoral joint replacement and at least partially
textured so as to provide an abrasive surface for preparing a bone
for receiving said patello-femoral joint replacement device.
15. The system of claim 12, wherein said drill guide comprises a
drill guide block for positioning against a bone to be drilled,
said drill guide block defining a drill guide passage which is
sized and configured to slidably guide a drill bit from an entrance
on one side of said drill guide block through and out of the
opposite side of said drill guide block, said drill guide block
providing a stable guide to facilitate drilling an intramedullary
canal.
16. The system of claim 15, wherein said drill guide block is
provided with a handle configured to permit a user to position said
drill guide block during operation.
17. The system of claim 15, wherein said drill guide block is
provided with a drill guide stylus, said drill guide stylus being
sized and configured to provide a referencing contact between the
anterior surface of a femur of a patient and a drill guide
stylus-femoral contact point located at the proximal end of said
drill guide stylus, said drill guide stylus providing stability for
said drill guide block during operation of said drill guide.
18. The system of claim 17 wherein said drill guide block is
provided with at least one drill guide positioning point projecting
from the surface of the drill guide block which is placed against
the bone during operation, said positioning point providing a
additional stabilizing means for said drill guide.
19. The system of claim 12, wherein said cutting guide comprises:
an intramedullary rod sized and configured to be insertable into an
intramedullary canal provided in the femur of a patient, said
intramedullary rod having at least one groove provided in its
surface and oriented along the longitudinal axis of said
intramedullary rod, a cutting guide member which is connected to a
proximal end of said intramedullary rod, said cutting guide member
being bifurcated along the longitudinal axis of said cutting guide
member so as to define a cutting guide slot, which is sized and
configured to slidably guide a bone saw during operation of said
cutting guide, and a stylus arm movably connected to the proximal
end of said cutting guide and sized and configured to provide a
stabilizing contact point between a stylus-femoral contact point of
said stylus arm and the anterior surface of a femur of a
patient.
20. The system of claim 19, wherein said cutting guide includes at
least one anchor guide which defines a respective anchor guide
portal, said at least one anchor guide being positioned on the saw
guide member so as to provide anchoring points through which a
surgeon can drill anchoring holes in the bone of the patient and
can affix anchors through said anchor guide portal into said bone
of the patient to provide stability during operation, said stylus
arm and said anchor guide providing multiple stabilization points
for said cutting guide.
21. A kit for use in implanting a patello-femoral joint replacement
device in a patient, said kit comprising: a petallo-femoral joint
replacement device, a drill guide for stabilizing and positioning a
drill bit in the operation of drilling an intramedullary canal in
the femur of a patient, and a cutting guide for stabilizing and
positioning a bone saw blade in the operation of providing a cut to
the anterior surface of the femur of a patient.
22. The kit of claim 21, further comprising a bone rasp, for
preparing the surface of a femur of a patient to receive said
petallo-femoral joint replacement device.
23. The kit of claim 22, further comprising an impactor for
forcibly inserting components of said drill guide, said cutting
device, and said patello-femoral joint replacement device into the
prepared surface of the femur of a patient.
24. A method of implanting a patello-femoral joint replacement
device in a patient in need of such joint replacement, the method
comprising: providing a drill guide, a cutting guide having an
intramedullary rod component, and a patello-femoral joint
replacement device, said replacement device having a femoral
implant component and a patellar implant component, surgically
exposing the patello-femoral joint of said patient, securing said
drill guide to the distal end of the femur of a patient and using
said drill guide to precisely position a drill bit in relation to
said femur, using said drill bit to prepare an intramedullary canal
in said femur, removing said drill bit and drill guide, securing
said cutting guide to said femur by insertion of said
intramedullary rod into said intramedullary canal of said femur so
as to provide a precise guide for a cutting bone cutting
instrument, cutting the anterior surface of the femur so as to
prepare said anterior surface to have a substantially flat prepared
surface and removing said cutting guide from said patient,
implanting said femoral implant component into said prepared
anterior surface of said femur, implanting said patellar implant
component into said patient so as to provide a slidably
articulating joint between said femoral implant component and said
patellar implant component.
Description
[0001] This application claims priority from U.S. Provisional
Application Serial No. 60/356,876 filed Feb. 14, 2002. The entirety
of that provisional application is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to novel orthopedic joint
replacement implants and methods, and particularly to an improved
method and system for patello-femoral joint replacement through a
simpler, less invasive surgical approach with instrumented,
reproducible cuts.
[0004] 2. Background of the Technology
[0005] Patello-femoral joint replacement is a well known orthopedic
surgical procedure. A variety of conventional joint replacement
devices have been in use since the 1970's, however, unlike joint
prostheses, which are typically used in total knee replacement
surgery, conventional patello-femoral joint replacement devices
have not been widely accepted in the orthopedic community. This may
be due to the somewhat mixed clinical results that conventional
patello-femoral joint prostheses have demonstrated as presented in
the pertinent medical literature. The conventional prostheses
typically include femoral components that were larger, bulkier
devices contoured to fit the trochlear groove of the femur. Their
contoured geometry, however, made it almost impossible to develop a
precise method of preparing the diseased surface of the femur to
fit the geometry of the implant. Typically the surgeon when using
conventional patello-femoral joint replacement devices has to use
powered burrs to carve out the boney surface to accept the implant.
This makes the fit and alignment of the implants hard to reproduce,
and somewhat variable from case to case. This method, and the large
size of the implants, also led to difficulties, if and when, it may
be necessary to revise the implant. It is not uncommon for it to be
necessary to revise the implants to total knee replacements in
later years as the arthritis progresses. For this reason the
ability to easily perform a revision procedure without excess
sacrifice of bone is crucial.
[0006] The use of precise cutting guides for other knee replacement
procedures slowly came into practice in orthopedics in the early
1980's. Similar improvements in the devices and methods used in
patello-femoral joint replacement have not been seen. Prior to the
present invention, there have not been methods or surgical devices
that permit accurate, reproducible bone cuts in the replacement of
the patello-femoral joint.
[0007] Early attempts to improve the devices used in
patello-femoral joint replacement include those described in U.S.
Pat. Nos. 4,007,495 and 4,151,615. Both of these early patents
describe patello-femoral joint replacements, but they do not
address the method, or instrumentation required to implant the
products. Similarly, U.S. Pat. No. 3,878,566, which describes a
commercially successful patello-femoral joint device, provides no
improvement in the method of implanting the device as it simply
discloses that the prosthesis is implanted by simply burring out a
spot for it in the bone. There is no disclosure of a means or
method for aligning or guiding the surgeon's preparation of the
bone for improved implantation of the device. U.S. Pat. No.
5,609,644 includes claims, which are drawn to a patello-femoral
joint, however, only the patellar replacement component is
described in any detail and no device or method is disclosed that
would assist the surgeon in the accurate implantation of the
device.
[0008] U.S. Pat. Nos. 5,571,196 and 5,824,098, both issued to
Stein, attempt to address this need by describing a system of
instrumentation that includes an intramedullary guide rod and a
router frame for preparing a trough in the anterior femur. The
system disclosed by Stein does not retain the anatomical contour of
the femur and requires several additional steps in the operation
thereby making the process more complicated and more prone to
complications. The method of Stein is also far more invasive that
the present invention, and, unlike the present invention, once
implanted would not allow an uncomplicated revision, if necessary,
since the machined femoral trough taught by Stein is much more bone
sacrificing and is not aligned with standard total knee
geometries.
[0009] These prior art attempts to provide a patello-femoral joint
replacement system have all failed to incorporate a low profile
femoral implant design with geometrically defined angular surfaces
similar to those in the femoral components of total knee
replacements, combined with a series of simple precise cutting
guides, that provide accurate, reproducible cuts.
[0010] In response to this need the present invention described
herein has been developed.
SUMMARY OF THE INVENTION
[0011] It is the general object of the present invention to provide
a novel patello-femoral joint replacement system and method for use
thereof, that after implantation allows essentially normal, full
range motion of the prosthetic joint.
[0012] It is a further object of this invention to provide a
smaller, lower profile, femoral implant than conventional implants
with a flat anterior bone-facing surface providing improved
adhesion between the anterior surface of the femur and the femoral
implant, angling slightly superiorly to facilitate full range of
motion of the joint, said bone-facing surface incorporating a
roughened texture, recessed pockets, and undercut edges on the
bone-facing surface for enhanced fixation and retention of bone
cement; a concave articular surface which mates with the articular
surface of the patellar component; and an intramedullary stem for
alignment in the femoral canal.
[0013] It is still further an object of this invention to provide a
system of surgical instruments comprising an intramedullary guide
rod; an anterior femoral cutting guide, which adapts to, and is
based on the intramedullary guide rod; a guide for drilling with
precision the intramedullary canal of the femur, which has means
for aligning and positioning it relative to the anterior surface of
the femur; a conically shaped rasp or file for finishing the
anterior cut and preparing it for receiving the femoral implant; a
feeler gauge for accurately positioning the cutting guide; and an
impactor, as is commonly known in the art, for facilitating the
final seating of the femoral implant.
[0014] It is further an object of the present invention to provide
the system of surgical instruments described immediately above as a
kit, which can be provided with instructions for use, bone
adhesive, alternative embodiments or sizes of member components so
as to allow the surgeon to modify the system to fit the immediate
needs of the patient.
[0015] It is still further an object of this invention to provide a
femoral implant, which is the femoral resurfacing component of the
present invention, the implant requiring only one cutting step for
the bone to be prepared for implantation, incorporating a geometry
that facilitates later revision to a total knee, if necessary, and
articulating with a patellar component that incorporates a mating,
reciprocal, articular surface.
[0016] It is further an object of the present invention to provide
a method for patello-femoral joint replacement that includes the
process of making a smaller less invasive incision in the patient;
drilling with precision an intramedullary guide hole in the femur;
aligning a novel cutting guide to an intramedullary rod inserted in
the guide hole; making a single, precise cut on the anterior
surface of the femur; and implanting the femoral resurfacing
component of the system of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The exact nature of this invention, as well as its objects
and advantages, will become readily apparent upon reference to the
following detailed description when considered in conjunction with
the accompanying drawings, in which like reference numerals
designate like parts throughout the figures thereof and
wherein:
[0018] FIGS. 1A, 1B, 1C shows a front, side and back view
respectively of one embodiment of the femoral implant component of
the present invention.
[0019] FIGS. 2A, 2B shows a front and side view of one embodiment
of the patellar implant component of the present invention.
[0020] FIG. 3 shows an isometric view of one embodiment of the
cutting guide component of the present invention.
[0021] FIG. 4 shows an exploded view of the embodiment of the
cutting guide component of the present invention shown in FIG.
3.
[0022] FIG. 5 shows the cutting guide component of the present
invention shown in FIGS. 3 and 4 operationally disposed in contact
with the distal end of a femur.
[0023] FIGS. 6A, 6B show a plan and side view of one embodiment of
the feeler gauge component of the present invention.
[0024] FIG. 7 shows a side view of the drill guide component of the
present invention in place against the distal end of a femur for
drilling the intramedullary canal.
[0025] FIG. 8 shows a prospective view of the distal portion of one
embodiment of the bone rasp component of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The present invention provides a system, including a
patello-femoral joint replacement device, a series of instruments,
and a method of use of those instruments for implanting the
patello-femoral joint replacement device.
[0027] The patello-femoral joint replacement device is made up
generally of two articulating components, a femoral implant, best
demonstrated in FIGS. 1A-C and generally shown at (10) and a
patellar implant, best demonstrated in FIGS. 2A-B and generally
shown at (12).
[0028] As best shown in FIGS. 1A-C, the femoral implant (10) is
designed to replace the anterior surface of the distal portion of
the patient's femur. The femoral implant (10) includes an
anatomically shaped upper surface (14) with a centrally and
longitudinally oriented articulating groove (16) of a generally
concave configuration.
[0029] As best shown in FIG. 1A, the underside (18) of the femoral
implant (10) includes at least one, but preferably multiple
recessed pockets (20), at least one intramedullary stem (22), and a
circumferentially disposed undercut edge (24). At least a portion
and preferably the majority of the underside generally shown at
(18) of the femoral implant (10) is provided with a roughened
surface (26). A porous coating or the use of at least one,
preferably multiple spikes or pegs (27) to improve attachment and
adhesion can also be employed. The recessed pockets (20), undercut
edge (24), and the roughened surface (26) individually and together
provide a configuration that facilitates a firm and lasting
connection of an adhesive that serves to bond the underside (18) of
the femoral implant (10) to the prepared anterior surface of the
distal portion of the femur.
[0030] It is within the concept of the present invention to employ
any adhesive in the practice of the method of implanting the
present invention in a patient. Preferably a bone cement will be
employed.
[0031] As best shown in FIGS. 1A,B, the articulating groove (16)
continues without interruption from the upper surface (14) to
distally extending projection (28) that terminates angling slightly
superiorly at an articulating groove distal terminus (30). This
distal terminus (30), by presenting a slightly superior angle
enables the patello-femoral joint replacement device to have smooth
tracking of the patellar implant (12) in the articulating groove
(16) through the full range of motion of the joint, that is in
extremes of flexion.
[0032] The patellar implant (12), as best shown in FIGS. 2A,B,
includes an articulating surface (32) having a generally spherical
dome-shaped geometry and being sized and configured to slidably
articulate in a complementary fashion within the articulating
groove (16) of the femoral implant (10). The articulating surface
(32) can include a circumferentially disposed annular border (34)
having a slightly different geometry than that of the articulating
surface (32) and composed of different materials than that of the
articulating surface (32).
[0033] A securing surface (36) disposed on the opposite side of the
patellar articulating surface (32) is configured to facilitate
secure attachment to bone and can include a patellar roughened
surface (38) to facilitate bonding of an adhesive. The securing
surface also includes at least one bone anchor (40) that can be
configured to include an annular retaining groove (42). The
patellar roughened surface (38), the bone anchor (40), and the
annular retaining groove (42) independently and collectively serve
to facilitate a strong adhesive bond between the patellar implant
(12) and bone material. It is within the concept of the present
invention that the patellar implant (12) can have additional pegs
on the securing surface (36) to facilitate strong adhesion to the
bone.
[0034] The system of the present invention includes several
instruments which provide the using surgeon with the ability to
precisely drill and cut bone material of the distal portion of the
femur in such a way as to provide contact with the femoral implant
(10) that is far superior to conventional bone preparation
methods.
[0035] As best seen in FIGS. 3-5, the present invention provides a
bone cutting guide, generally shown at 44, that includes an
intramedullary rod (46) sized and configured for insertion into the
intramedullary space of a femur that has been prepared to receive
the same. The intramedullary rod (46) can be configured with one or
more groves (48) so as to provide a fluted surface along the
longitudinal axis of the intramedullary rod (46). This fluted
surface can facilitate insertion of the intramedullary rod (46)
into the bone so as to reduce the pressure imposed on the marrow of
the bone and thus reduce or avoid the pressure-induced result of
material being forced into the circulation system of the patient.
In a preferred embodiment of the present invention, the
intramedullary rod (46) is fixedly connected to cutting guide (44).
It is, however, entirely within the scope of the invention to
configure the intramedullary rod (46) to be releasably engaged to
the cutting guide (44) by a rod gripping member (50) that can be
selectively secured by means of a gripping member actuator (52).
Such an alternative embodiment of the cutting guide (44) can permit
removal and replacement of the intramedullary rod (46) with rods of
different configuration or different size.
[0036] Whether integrally formed with the intramedullary rod (46),
as in the preferred embodiment, or connect thereto by an
intermediary member, such as the gripping member (50), the
intramedullary rod (46) is releasably connected to a saw guide
member by at least one, preferably two cutting guide assembly rods
(56), which are sized and configured to slidably engage a like
number of assembly rod receiving portals (58). An assembly securing
member (60) is configured to releasably engage a securing member
portal (62) in such a manner so as to cause the receiving portal
(58) to secure the assembly rods (56) to the saw guide member
(54).
[0037] The saw guide member (54) is provided with a anchor portal
(64) that is sized and configured to receive a stylus arm anchor
rod (66). The stylus arm anchor rod (66) can be integrally
connected to the saw guide member (54) or preferably can be
releasably secured into the anchor portal (64) by passage of the
assembly securing member (60) through an anchor rod passage
(68).
[0038] A freely rotating stylus (70) is sized and configured to
provide at a distal end a stylus-femoral contact point (72). The
proximal end of the stylus (70) is attached at approximately a
right angle to a stylus rotation sleeve (74), which is sized and
configured to be circumferentially disposed and freely rotate
around the stylus arm anchor rod (66). A stylus retainer member
(76) can be provided to releasably retain the stylus (70) in its
rotatable configuration around the stylus arm anchor rod (66).
[0039] The saw guide member (54) is preferably partially bifurcated
by a saw guide slot (78) sized and configured to allow slidable
passage of a bone saw such as is commonly known in the art. The
distal end of the bifurcated portion of the saw guide member (54)
includes a guide connecting member (80) that can be a permanent
connection at or near the terminus of the saw guide member (54) or
can be a pin, screw, rivet, or any other connecting means that
serves to attach the ends of the bifurcated saw guide member (54).
Disposed on the outer surface of the bifurcated saw guide member
(54) is at least one, preferably two, anchor guides (82), which
individually define anchor guide portals (84). These anchor guide
portals are sized and configured to facilitate passage of a drill
bit that can be used by a surgeon to bore an anchoring hole, such
as an intramedullary canal, into the bone of a patient. Upon
removal of the drill bit from the anchor guide portals (84), the
surgeon can employ the anchor guide portals (84) as securing points
through which securing bone screws or the like can be passed to
provide additional attachment points for the cutting guide to the
bone of the patient during operation. Thus, the surgeon can employ
the stylus femoral contact point (72), and the two anchor guide
portals (84) to provide three separate securing points for the
cutting guide member to the bone. By this means, the surgeon can
ensure a stable and well-positioned cutting guide is in place prior
to employing a bone saw through the saw guide slot (78).
[0040] A feeler gauge (88) as is well known in the art and as shown
in FIGS. 6A,B can be sized and configured to align the saw guide
slot (78) in the cutting guide (44) with the targeted location on
the femur.
[0041] The system of the present invention can also include a drill
guide, as seen in FIG. 7 and generally shown at (90). The drill
guide (90) includes a drill guide block (92) that defines a drill
guide passage (94). The drill guide block (92) is connected to a
drill guide handle (96) by which the surgeon can manipulate and
steady the drill guide (90) during operation. A drill guide stylus
(98) can be provided as attached to the drill guide block (92) at a
proximal end and terminating at a drill guide stylus-femoral
contact point (100) at a distal end. The drill guide block can be
provided with at least one, preferably two drill guide securing
points (102) by which the using surgeon can obtain additional
stability of the drill guide (90) during operation. The drill guide
(90) of the present invention can be provided with three
stabilizing points during operation: the drill guide stylus and the
two drill guide securing points. Once positioned and secured, the
drill guide (90) can be employed by the surgeon to facilitate the
proper alignment and accurate drilling of the intramedullary canal.
Once properly drilled, the cutting guide (44) of the present
invention can be inserted and accurately positioned for use.
[0042] The system of the present invention can also include a bone
rasp (104). The bone rasp (104) can be conically shaped and at
least a portion of the conical terminus can be provided with an
abrasive surface as is well known in the art. The bone rasp (104)
is configured to facilitate the removal of any burrs, osteophytes
or remaining projections of bone after the cutting step of the
method of the present invention.
[0043] In the method of the present invention, each of the
components described above are used as indicated to systematically
prepare the femur for receiving the patello-femoral joint
replacement device described herein. The drill guide (90) after
being properly positioned and used by the surgeon to facilitate the
drilling of the femur and the formation of a receiving point for
the intramedullary rod (46) is removed. The cutting guide (44) of
the system of the present invention is then positioned with the aid
of the feeler gauge (88) as described above and used by the surgeon
to facilitate a accurate cutting of the bone to remove the anterior
surface of the distal end of the femur thus providing a
substantially flat receiving surface on the bone. After removal of
the cutting guide (44) the femoral implant (10) is positioned and
fixedly attached to the anterior surface of the femur wherein the
intramedullary stem (22) of the femoral implant (10) is now
positioned in the hole earlier drilled by the surgeon and earlier
used to assist in the securing of the cutting guide (44). The
patellar implant (12) is then implanted by the surgeon and placed
in articulating engagement with the femoral implant (10) so as to
provide a fully articulating and functional patello-femoral joint
replacement device.
[0044] In the manufacture of the instruments and devices of the
system described herein, the components can be integrally formed or
separately formed and assembled using permanent or temporary
connections as are well known in the art.
[0045] In the preferred embodiment, the implant components would be
manufactured from implantable grades of ultra-high molecular weight
polyethylene and cobalt chromium molybdenum alloy. The instruments
of the system would be manufactured from surgical grade stainless
steels. It is within the concept of the present invention that the
components may be manufactured from any implantable materials or
surgically acceptable materials known in the art, such as, for
example titanium alloys, ceramics, composites, or the like.
[0046] It is important to recognize that various modifications in
the above described configuration and construction of the present
invention can be made without departing from the concept of the
invention as the specification is only illustrative of the
invention, which is limited only by the following claims.
* * * * *