Note: Descriptions are shown in the official language in which they were submitted.
1 328955
1 64680-418G
Title,- BONE PLATE FOR USE IN
MODULAR FEMORAL FIXATION SYS~M
This is a division of our copending Canadian Patent
Application No.540,188 filed 19 June 1987.
Internal fixatlon of femoral fractures is one of the
most common orthopedic surgical procedures. Many different typeæ
of femoral fractures are encountered in practice, including
fractures in the femoral neck, intertrochanteric, mid-shaft and
distal condylar regions. The femoral bone will sometimes fracture
cleanly into two large fragments along a well-defined fracture
line, and on other occasions fracture into many smaller fragments.
Often, more than one type of fracture will exist concurrently in
different regions of the femur of an injured patient.
A wide variety of implants have been developed over the
years for use in the internal fixation of femoral fractures.
Although numerous excellent design achievements have been
realized, several general problem areas remain. Firæt, almost all
of the currently available implants have a highly æpecialized
application limited to only one specific anatomical location in
the femur. Thus, a hospital must maintain at great expense a very
large and variegated inventory of different implants to handle all
expected contingencies. ~hese implants are generally not
compatible, i.e. they cannot be interconnected together in case of
a complicated fracture pattern extending into different anatomical
regions of the femur. Second, each implant has its own peculiar
attributes and deficiencies, and the use of many of the known
implants involves the u e of a surgical technique that is unique
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to that implant and so~etimes complicated and dlfflcult as well.
Consequently, the opportunities for
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improper implant selection and surgeon error during
implantation are inevitably increased. Finally, tissue
reactions with implants made of stainless steel and
certain other surgical implant alloys tend to reduce
the useful lifetime of the implants and require
premature removal from the patient's body.
One very commonly utilized femoral internal
fixation device is an elongated implant (nail, screw,
pin, etc.) adapted to be positioned along the
1~ longitudinal axis of the femoral neck with its leading
end portion in the femoral head so as to stabilize a
fracture of the femoral neck. The elongated implant
may be implanted by itself or connected to another
implant such as a side plate or intramedullary rod.
The leading end portion of the implant typically
includes means to positively grip the femoral head bone
(external threads, expanding arms, etc.), but the
inclusion of such gripping means can introduce several
significant problems. First, implants with sharp edges
2~ on the leading end portion, such as the externally
threaded implants, exhibit a tendency to migrate
proximally towards the hip joint bearing surface after
implantation. Such proximal migration under
physiological loading, which is also referred to as
2S femoral head cut-out, can lead to significant damage to
the adjacent hip joint. Also, the externally threaded
implants can generate large stress concentrations in
the vicinal bone during implantation which can lead to
stripping of the threads formed in the bone and thus
obviously a weakened grip. The movable arms of known
expanding arm devices are usually free at one end and
attached at the other end to the main body of the
leading end portion of the implant. As a result, all
fatigue loading is concentrated at the attached ends of
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the arms and undesirably large bending moments are realized at the
points of attachment.
As stated above, known elongated implants used to
stabilize fractures of the femoral neck are often connected in use
to a side plate which in turn is secured to the outer cortical
wall of the adjacent femoral shaft, for example with bone screws.
This type of assembly is often selected when a femoral neck
fracture is a part of a more complicated fracture pattern
including also one or more fractures in the metaphyseal and/or
diaphyseal regions of the femur. Clearly, the surgeon desires to
be able to select the appropriate length of the side plate
depending upon the particular traumatic condition of the patient'~
femur. However, the surgeon's flexibility in this regard
typically requires the hospital to maintain a costly inventory of
implants.
It is desired to provide a modular system of femoral
internal implants, and instrumentation therefor, that can be
employed to treat a number of different fracture patterns and
other disorders with a minimal number of interconnectable system
components involving simple uncomplicated operational procedures
in which surgical invasiveness and operation times are minimized.
The present invention provides an elongated bone plate
adapted to be secured to a patient's bone having an upper surface,
a lower surface intended to be adjacent the patient's bone in use
and two side surfaces connecting the upper and lower surfaces,
with the thickness of the plate being substantially constant
between the two side surfaces, the width of the upper surface
being greater than the width of the lower surface, said side
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surfaces belng tapered inwardly toward one another from said upper
surface to said lower surface, with sald bone plate being adapted
to be secured to the patient's bone by means of bone fasteners
received in apertures in the bone plate.
The bone plate may form part of a novel kit for use ln
the amelioration of a number of different types of femoral
disorders resulting from in~ury, disease or congenital defect with
a minimal number of interconnectable components. The kit
preferably comprises at least the following components: 1) an
elongated epiphyseal/metaphyseal implant having a leading end
portion and a trailing end portion and adapted to grlp bone at its
leading end portion; 2) an intramedullary rod having a distal end
and a proximal end; 3) an angled side plate comprising an
elongated plate portion adapted to be secured to the outer
cortical wall of the femoral shaft and an integral hollow sleeve
extending at an angle from one end of the plate portion so that
said hollow sleeve extends into the femur when the plate portion
is secured to said cortical wall; and 4) means for connecting the
epiphyseal/metaphyseal implant to the intramedullary rod adjacent
to one of the ends of the rod with the epiphyseal/metaphyseal
implant at an angle with respect to the intramedullary rod.
The components of the novel kit are dimensioned such
that the elongated epiphyseal/metaphyseal implant is capable of
being connected to the angled side plate by the insertion of the
trailing end portion of the epiphyseal/metaphyseal implant into
the hollow sleeve of the angled side plate and the elongated
epiphyseal/metaphyseal implant is also capable of being connected
to the intramedullary rod with the use of said connecting means.
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Thus the same epiphyseal/metaphyseal implant can be either
connected to the intramedullary rod, to form for example a Y-nail
type of assembly to treat an unstable subtrochanteric fracture
pattern, or connected to the angled side plate, to form for
example a side plate-pin assembly to treat a dlfferent fracture
pattern. The intramedullary rod may be either connected to the
elongated epiphyseal/metaphyseal implant or implanted
independently of said implant and the angled side plate.
The novel kit can be used to treat a variety of trauma
conditions as well as to ameliorate other types of femoral
disorders including non-unlons, congenital deformlties and
pathological deformities (e.a. Paget's disease), and can also be
utilized in the prophylactic
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fixation of weakened bone, bone defects, etc., and in
the performance of osteotomies. Simple and
uncomplicated surgical techniques can be employed and
operating times and implant inventories kept at a low
level.
As used herein the term "elongated epiphyseal/-
metaphyseal implant" refers to an elongated implant
adapted to be used in such a manner that it extends
after implantation from the epiphyseal region of the
proximal femur into the adjacent metaphyseal region,
or from the lateral to the medial epiphyseal region of
the distal femur. In general, the elongated
epiphyseal/metaphyseal implant can be a pin, nail,
screw, etc. Preferably, the intramedullary rod is
axially cannulated and is provided with at least one
through bore adjacent its distal end for reception of a
locking screw.
The modular femoral implant system advantageously
includes components additional to the essential
epiphyseal/metaphyseal implant, intramedullary rod,
angled side plate and epiphysealJmetaphyseal implant-
intramedullary rod connection means. Thus, the kit
preferably includes an elongated bone plate adapted to
be secured to the outer cortical wall of the femoral
shaft. The elongated bone plate and angled side plate
are dimensioned such that the elongated bone plate can
be connected to the plate portion of the angled side
plate to provide an extension of the effective length
of said plate portion without having to inventory two
complete angled side plates. The elongated bone plate
can of course be utilized by itself in a conventional
manner, if desired. Most preferably, several elongated
bone plates of variable length are included in the kit.
In a further preferred embodiment of the invention
the kit includes a distal buttress plate including a
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relatively flat elongated proximal portion adapted to
be secured to the lateral distal femoral shaft and a
relatively curved distal portion adapted to be secured
to the lateral distal femoral condyle. In this
embodiment the kit includes at least one elongated bone
plate that is capable of being connected to each of the
plate portion of the anqled side plate and the proximal
portion of the distal buttress plate for effective
length extension purposes, as desired.
lU The novel kit of the present invention preferably
includes a plurality of threaded self-tapping cortical
bone screws for use in securing the elongated plate
portion of the one or more angled side plates to the
outer cortical wall of the femoral shaft and, when the
kit includes an intramedullary rod with a distal
through bore and one or more elongated bone plates,
securing the distal end of the intramedullary rod to
the distal femur, securing said bone plate(s) to the
outer cortical wall of the femoral shaft, and
2~ connecting said plate portion~sJ and bone plate ~5)
together in axial alignment. The kit preferably
includes a plurality of such screws each having a head
and a threaded shank, with said screws being identical
except for variations in the length of the threaded
shanks. Although not every one of these screws can be
used in all of the capacities set forth above (for
example short cortical screws cannot be used to secure
the distal end of the intramedullary rod), the
29 provision of a plurality of threaded self-tapping
cortical bone screws of universal screw head and screw
shank design (except for variations in screw shank
length) provides substantial opportunities for
interchangeability in use and reduced inventory levels,
and requires the surgeon to be familiar with only one
~5 set of cortical screw characteristics, attributes and
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techniques of use. Furthermore, said bone screws can
be used independently as bone fixation screws to hold
fragments of bone together during healing of a
fracture. Most preferably, the heads of the cortical
screws and the apertures in the plate portion~s) and
bone plate(s) intended to receive them are configured
in such a manner that the screws are capable of a
universal rotation with respect to the plate portion or
bone plate within a cone having an apex angle of at
least about 20 when the screw head is fully advanced
into the aperture receiving it. Thus, for example,
the underside of the universal screw head may be
spherically rounded (convex towards the bone) and the
abutting surfaces of the screw-receiving apertures
complimentary thereto ~and of course concave away from
the bone).
Preferably, the components of the novel kit of the
invention are made of a resilient, physiologically
inert titanium-base alloy such as Ti-11.5Mo-6Zr-4.5Sn,
Ti-6Al-4V or Ti-3Al-2.5V. The physiological inertness
of such alloys reduces the potential for adverse tissue
reactions (as compared to e.q. stainless steel) and
thus will serve to increase product lifetime ln vivo
after implantation. Also, most of the currently
,5 available implants for the internal fixation or
amelioration of femoral fractures or other disorders
are made of highly rigid materials, thus leading in
many circumstances to excessive "stress shielding" in
which too much of the stresses applied to the femur are
borne by the implant rather than the healing bone in
the fracture region. Stress shielding may delay
fracture healing and weaken the surrounding bone. This
problem of stress shielding is greatly alleviated by
making the components of the kit out of a resilient
titanium-base alloy.
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In a preferred distribution of components, the kit
comprises: 1) two epiphyseal/metaphyseal implants of different
length, 2) an angled side plate in which the hollow sleeve and
plate portion are mutually oriented at an oblique angle so that
the hollow sleeve is adapted to extend into the intertrochanteric
region when the plate portion is secured to the outer cortical
wall of the adjacent femoral shaft, 3) an angled side plate in
which the hollow sleeve and plate portion are substantially
perpendicular so that the hollow sleeve is adapted to extend lnto
the distal condylar region of the femur when the plate portion is
secured to the outer cortical wall of the adjacent distal femoral
shaft, 4) an intramedullary rod (preferably having a through bore
adjacent it3 distal end), 5) means for connecting the shorter of
the two epiphyseal/metaphyseal implants to the intramedullary rod
adjacent to the proximal end of the rod to form a Y-nail type of
assembly, 6) a plurality of cancellous and cortical bone screws,
and 7) at least one elongated bone plate capable of being
connected in axial alignment to the plate portion of each of ~he
angled side plates for effective length extension purposes. The
shorter epiphyseal/metaphyseal implant is also capable of being
connected to the substantially perpendicularly-angled side plate,
while the longer epiphysealtmetaphyseal implant is capable of
being connected to the obliquely-angled side plate. With this
highly preferred distribution of components, the components of the
kit can be assembled together in different ways or used
independently to treat or ameliorate most of the femoral fracture
conditions and other femoral disorders commonly encountered by
orthopedic surgeons.
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The elongated bone plate of the present invention has an
upper surface intended to face away from the patient's bone and a
lower surface intended to face towards the patient's bone.
Because the lower surface adjacent the bone is thinner (preferably
70% to 90% in width) than the upper surface at which stresses from
physiological bending moments applied to the plate tend to be at a
maximum, the necessary periosteal tissue stripping adjacent the
bone for implantation purposes can be reduced without excessively
sacrificing the strength of the bone plate under bending. In one
preferred embodiment said upper and lower surfaces are defined in
transverse bone plate cross-sections by arcs of two concentric
circles, while the two side surfaces are defined thèrein by two
straight radial lines passing through the common center of said
concentric circles.
It is also preferred that an elongated bone plate of the
~nvention comprise two parallel integral downwardly-extending
rails located at opposite sides of the lower surface and extending
along substantially the entire length of the bone plate. These
two rails serve to lift the lower surface of the bone plate away
from the surface of the patient's bone so as to permit enhanced
vascularization of the bone directly beneath the lower surface and
thus avoid any excessive weakening of that bone tissue.
It is highly advantageous to provide an elongated bone
plate that can be readily connected to the elongated plate portion
of another surgical implant in a simple, foolproof, non-time
consuming surgical method so as to effectively provide an
extension of the length of said elongated plate portion. The
other surgical implant may be, for example, another bone plate, an
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angled side plate, a distal buttress plate, or the like. Thus, a
further advantage of the novel elongated bone plate of the
invention is that it can be readily connected to a surglcal
implant having an elongated plate portion adapted to be secured to
a patient's bone by means of bone fasteners received in apertures
in the elongated plate portion, which plate portion has upper and
lower surfaces, with a cavity being formed in the lower surface of
the plate portion at a free end thereof, said cavity extending
longitudinally from said free end to a shoulder defining an end of
the cavity and sald cavlty havlng a transveræe cross-sectlon
complementary to that of the elonyated bone plate of the
invention. An important consequence of the complementary designs
of the transverse cross-sectlons, lncluding downwardly-lnwardly
tapered side walls, of the surglcal lmplant cavlty and elongated
bone plate is that the bone plate "dovetails" with the surgical
lmplant so that lt can enter and be removed from the cavlty ln the
surglcal implant only by relatlve axlal movement through the
cavlty openlng at the free end of the elongated plate portlon of
the surgical lmplant. Also, no relative rotatlon is permltted
between the surglcal lmplant and bone plate. When the end of the
bone plate abuts the shoulder at the other end of the cavlty, no
relatlve translatlonal movement is posslble between the surglcal
lmplant and bone plate except for axial separation. By insuring
that at least one bone fastener-receiving aperture in the
elongated plate portion of the surgical implant overlies a bone
fastener-receiving aperture in the bone plate when the plate is
inserted into sald cavity ln the surglcal implant and abuts the
shoulder at the end of the cavlty, a stable and secure assembly of
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surgical ~mplant and bone plate, ln which the length of the
elongated plate portion of the surgical implant is effectively
extended by the elongated bone plate, ~an be realized when the
assembled surgical implant and bone plate are secured together to
the patient's bone.
The invention will be described in detail with reference
to various preferred embodiments thereof. Reference to these
embodiments does not limlt the scope of the invention, which is
limited only by the scope of the claims. In the drawings:
FIGURE 1 is an exploded side elevational view of an
epiphyseal/metaphyseal implant of the present invention including
an expansion sleeve and an elongated plunger;
FIGURE 2 is a longitudinal sectional view of the
expansion sleeve of the implant of FIGURE 1 in the rest position
of the sleeve, taken along a plane including the longitudinal axis
of the sleeve;
FIGURE 2A is an end view of the expansion sleeve of
FIGURE 1 in the rest position of the sleeve;
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FIGS. 3 to 5 are longitudinal sectional views of
the implant of FIG. 1, taken along a plane including
the common longitudinal axis of the plunger and sleeve,
showing three stages in the insertion of the plunger
into the sleeve held in a patient's bone;
FIG. 6 is a top plan view of a proximal angled
side plate included in a modular implant system or kit
of the invention;
FIG. 7 is a sectional view taken along line 7-7 of
1~ FIG. 6;
FIG. 8 is a sectional view taken along line 8-8 of
FIG. 6;
FIG. 9 is a top plan view'of an elongated bone
plate included in a modular implant system of the
invention;
FIG. 10 is a sectional view taken along line lO-10
of FIG. 9;
FIGS. llA and llB are side elevational views of a
pair of cortical bone screws of different shank lengths
included in a modular implant system of the invention;
FIGS. 12A and 12B are side elevational views of a
pair of cancellous bone screws of different shank
lengths included in a modular implant system of the
invention;
FIG. 13 is an enlarged top plan view of each of
the cortical bone screws of FIGS. llA and llB;
FIG. 14 is a sectional view taken along line 14-14
of FIG. 9 showing the permitted side-to-side angulation
of one of the cortical bone screws of FIG. llA within
one of the bone screw-receiving apertures provided in
the bone plate of FIG. 9;
FIG. 15 is a lateral elevational view of the
epiphyseal/metaphyseal implant of FIG. l, the proximal
angled side plate of FIG. 6, the elongated bone plate
of FIG. 9 and a plurality of cortical bone screws of
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the type shown in FIGS. llA and llB, all connected
together and secured to a patient's femur, with the
femur shown partly in section
FIG. 16 is a sectional view taken along line 16-16
of FIG. 15;
FIG. 17 is a sectional view taken along line 17-17
of FIG. lS;
FIG. 18 is a side elevational view of a surgical
implant insertion instrument of the invention shown
assembled with the expansion sleeve and elongated
plunger of the implant of FIG. 1;
FIG. 18A is a sectional view taken along line
18A-18A of FIG. 18;
FIG. 19 is a side elevational view of an
intramedullary rod having an anterior-posterior bow
included in a modular implant system of the invention;
FIG. 20 is another side elevational view of the
intramedullary rod of FIG. 19, as viewed in a direction
perpendicular to that of FIG. 19;
2~ FIG. 21 is a sectional view taken along line 21-21
of FIG. 19;
FIG. 22 is a longitudinal view, partially in
section, of a proximal end region of an intramedullary
rod of the type shown in FIG. 19, illustrating the
optional feature of a detachable hollow sleeve secured
to the proximal end portion of the intramedullary rod;
FIG. 23 is a top plan exploded view of an
elongated intramedullary rod-epiphyseal/metaphyseal
implant connection piece, locking screw and locking
shoe included in a modular implant system of the
invention;
FIG. 24 is a front view, partially in section, of
the articles shown in FIG. 23;
FIG. 25 is an elevational view of an
3j epiphyseal/metaphyseal implant of the type shown in
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1 328955
FIG. 1 but of shorter length, the intramedullary rod of
FIG. 19 and the connection piece, locking screw and
locking shoe of FIG. 23, all connected together and
secured to a patient's femur, with the femur shown in
section, wherein the epiphyseal/metaphyseal implant and
connection piece form together an elongated
cross-member;
FIG. 26 is a bottom plan view of a distal angled
side plate included in a modular implant system of the
invention;
FIG. 27 is a sectional view taken along line 27-27
of FIG. 26;
FIG. 28 is an elevational view of an
epiphyseal/metaphyseal implant of the type shown in
FIG. 1 but of shorter length, the distal angled side
plate of FIG. 26, the elongated bone plate of FIG. 9
and a plurality of cortical bone screws of the type
shown in FIGS. llA and llB, all connected together and
secured to a patient's femur, with the femur shown in
: 2~ section;
FIG. 29 is a top plan view of a distal buttress
plate included in a modular implant system of the
invention;
FIG. 30 is a side elevational view of the distal
?S buttress plate of FIG. 29;
FIG. 31 is an elevational view of the distal
buttress plate of FIG. 29, the elongated bone plate of
FIG. 9 and a plurality of cortical and cancellous bone
screws of the type shown in FIGS. llA, llB, 12A and
3~ 12B, all connected together and secured to a patient's
distal femur, with the femur shown in section; and
FIGS. 32A and 32~ are side elevational views of a
pair of cortical bone screws of different shaft lengths
suitable for use as distal locking screws.
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Except as otherwise indicated, all of the implants
shown in FIGS. 1 to 32B depicting various preferred
embodiments of the invention are made of a resilient,
physiologically-inert titanium-base alloy.
An elongated epiphysealtmetaphyseal implant 1 of
the invention is shown in FIG. 1. Implant 1 comprises
an integral substantially cylindrical expansion sleeve
3 and an elongated plunger 5. Sleeve 3 includes a
smoothly rounded circumferentially-closed dome 7 at one
end, a circumferentially-closed circular ring 9 at the
opposite end, and a plurality ~eight in the embodiment
shown in FIGS. 1 to 5) of identical substantially
straight elongated thin resilient strips 11 extending
between, and connected at their opposed ends by and to,
dome 7 and ring 9. A centrally-disposed threaded axial
through bore 15 is provided in dome 7 for releasably
securing an elongated insertion rod to the dome.
Strips ll have textured outer surfaces to enhance the
bone-gripping action of the implant and define together
the cylindrical wall of sleeve 3, which sleeve wall has
in the rest position of the sleeve an outer diameter
essentially equal to the outer diameter of ring 9. As
is shown in FIG. 2, each of the strips 11 is of varying
thickness along its length so that the sleeve wall has
in the rest position of the sleeve an inner diameter in
a region r1 adjacent ring 9 equal to the inner diameter
of ring 9 and an inner diameter in a region r2 spaced
from ring 9 reduced from the inner diameter of ring 9.
The strips 11 do not touch each other along their
lengths in the rest position of the sleeve, but are
instead separated by an equal number of longitudinal
openings, e.q. 13.
Plunger 5 includes at one end thereof a
- substantially cylindrical body portion 17 having a
diameter essentially equal to the inner diameter of
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ring 9 of sleeve 3, and a cylindrical stem portion 19
having a smaller diameter than body portion 17
extending from body portion 17 to the other end of the
plunger. Plunger 5 is cannulated along its
S longitudinal axis, as shown in FIG. 1. An internally
threaded recess 20 is provided at the trailing end of
stem portion 19 for engagement with an externally
threaded tool to remove plunger 5 from the patient's
bone after implantation, if desired.
The body portion 17 of plunger 5 includes a raised
annular lip 18 adjacent the trailing end of portion 17,
a groove 10 is provided in the inner wall of ring 9 and
a plurality ~eight in the embodiment shown in FIGS. 1
to 5) of relatively short slots 12 (open at the
trailing edge of ring 9) are provided in the closed
ring 9, all for a purpose to be described below.
FIGS. 3 to 5 show how bone implant 1 is actuated
to grip a patient's bone B at the leading end portion
of the implant. The expansion sleeve 3 is inserted
into and held within a cylindrical cavity C in the
patient's bone B by means of an insertion rod 21 having
an externally threaded end portion 23 screwed into the
internally threaded bore 15 of sleeve 3. Insertion rod
21 extends along the longitudinal axis of sleeve 3 and
is cannulated to fit over a guide wire 25. Cannulated
plunger 5, which is in a sliding fit over rod 21, is
advanced along rod 21 towards sleeve 3 (i.e. from left
to right in FIG. 3) with its substantially cylindrical
body portion 17 in the leading position. After the
body portion 17 of plunger 5 first contacts the
elongated strips 11 at the beginning of region r2 (see
FIG. 4), the continued advancement of plunger 5 into
the interior of sleeve 3 causes the eight strips 11 to
expand radially outwardly against the wall of the
~5 cavity C and securely grip the patient's bone B. When
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the plunger 5 is fully advanced within the expansion
sleeve 3 (see FIG. 5), the raised lip 18 fits into the
groove 10 to lock the sleeve 3 and plunger 5 against an
undesired axial disengagement after implantation of the
implant 1. The equally-spaced (circumferentially)
slots 12 impart a slight resiliency to the ring 9 which
allows the rib 18 to snap into the groove 10.
Additionally, when the plunger is fully advanced within
the sleeve, the cylindrical wall of the sleeve 3 has
~ taken on a generally barrel-shaped contour, which
results from the fact that the opposite ends of each
strip 11 are fixed to dome 7 and ring 9, respectively.
Since the expansion sleeve 3 is made of a resilient
material the strips 11 expand radially outwardly in
elastic deformation when the plunger 5 is fully
advanced into the expansion sleeve 3. If desired, an
extrudable bone cement or bone filler material can be
inserted into the sleeve 3 so that when the plunger 5
is advanced into the sleeve 3 the bone cement or bone
2~ filler is extruded through the openings 13 to the
sleeve-bone interface.
An insertion instrument 27 of the invention for
use in the implantation of bone implant 1 is shown in
FIG. 18 assembled with sleeve 3 and plunger 5.
Insertion instrument 27 includes the elongated
axially-cannulated insertion rod 21 (upon which plunger
5 can slide) having an externally threaded end portion
23 adapted to be screwed into threaded bore 15 in dome
7 of sleeve 3 and an externally smooth portion 29
extending from the threaded portion 23, a hollow sleeve
31 capable of sliding movement upon smooth portion 29,
a handle 33 and a means 35 for advancing the hollow
sleeve 31 along the smooth portion 29 of rod 21 towards
the externally threaded portion 23 of rod 21. The
sleeve advancing means 35 comprises a knurled knob 37
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threaded upon an externally threaded portion 39 of the
elongated rod 21. As knob 37 is turned it pushes
against sleeve 31. Preferably, a nylon washer (not
shown in the figures) is fitted between knob 37 and
j sleeve 31. A guide pin 41 provided on the inner wall
of sleeve 31 is received within a longitudinal groove
provided in threaded portion 39 (see FIG. 18A~. In
use, the surgeon holds handle 33 in one hand and turns
knob 37 with the other hand to advance hollow sleeve 31
toward the expansion sleeve 3. The hollow sleeve 31
abuts the plunger 5, which is also fitted on the
insertion rod 21, and thus in turn forces plunger 5
along the rod until the plunger is advanced into the
expansion sleeve 3. As the cylindrical body portion 17
of the plunger 5 is being pressed by knob 37 and hollow
sleeve 31 against the elongated strips 11 of the
expansion sleeve 5 and forcing the strips 11 to expand,
the surgeon can stop advancement of the plunger into
the expansion sleeve-(to rest, to assess the surgical
2~ situation, or for any other reason) without relaxing
the force being placed on the plunger by the insertion
instrument 27. In such a situation movement
of hollow sleeve 31 and plunger 5 along insertion rod
21 away from expansion sleeve 5 is positively prevented
by the structure of the sleeve advancing means 35.
After the implantation of the expansion sleeve 3
and the plunger S has been completed, with the plunger
fully advanced within the interior of the sleeve, the
guide wire 25 and the insertion rod 21 are removed from
the patient's bone, although it is contemplated that an
appropriately dimensioned insertion rod and/or guide
wire might be left in place in the patient's bone to
form a part of the implanted elongated bone implant.
A proximal angled side plate 43 which may be
included in a modular implant system or kit of the
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:
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1 328955
invention is shown in FIGS. 6 and 7. Proximal angled
side plate 43 includes an elongated plate portion 45
adapted to be secured to the outer cortical wall of the
femoral shaft and an integral hollow sleeve 47
extending from one end of plate portion 45. The
elongated plate portion 45 has an upper surface 49 and
a lower surface 51 intended to be adjacent the
patient's bone in use, while the hollow sleeve 47 is
provided with a longitudinal cylindrical through bore
53 extending from upper surface 49 to the free end of
hollow sleeve 47. As shown in FIG. 7, the elongated
plate portion 45 and hollow sleeve 47 are oriented at
an oblique angle of about 130-150 so that hollow
sleeve 47 is adapted to extend into the
lS intertrochanteric region of the femur when elongated
plate portion 45 is secured to the outer cortical wall
of the adjacent femoral shaft.
As used herein, the term "adapted to be secured to
the outer cortical wall" of a bone (e.q. a femur) means
2~ that an implant is adapted to be secured to a bone in
such a way that it abuts the outer cortical wall of the
bone. As one example, an implant may be provided with
a plurality of apertures along its length for the
receipt of bone fasteners (e.g. bone screws, nails,
pins, bolts, rivets, or the like) used to secure the
implant to the outer cortical wall.
As is shown in FIGS. 6 and 7, three circular
through apertures 55, 57 and S9 are provided in the
elongated plate portion 45 of the proximal angled side
3~ plate 43 for the receipt of three bone screws, one in
each aperture. These three apertures are staggered
with respect to the longitudinal axis of plate portion
45 (see FIG. 6~ in order to reduce stress
concentrations in the secured plate portion and in the
bone. As shown in FIG. 7, the upper portions 61 of the
; ., . ,. : .. - . .
,. , . ~ .. ; . .. .
: ' :~ ' : : ,.
; ..
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i 1 328955
walls of apertures 55, 57 and 59 adjacent upper surface
49 are preferably identical, concave-upward spherical
surfaces. These identical spherical surfaces are
adapted for cooperation with spherically-headed
cortical and cancellous bone screws, as is discussed
below. Two of these apertures, 57 and 59, communicate
with an elongated cavity 63 formed in the lower surface
51 of plate portion 45, which cavity extends
longitudinally from the free end 65 of plate portion 45
to a shoulder 67. Cavity 63 is adapted to receive an
end portion of an elongated bone plate of the invention
in a sliding fit, as will be described below. The
lower surface 51 of elongated plate portion 45 is
slightly curved (as viewed in transverse cross-sections
of plate portion 45 (see FIG. 8)) to conform to the
outer cortical wall of a femur.
An elongated bone plate 69 of the invention
adapted to be secured to a patient's bone is shown in
FIGS. 9 and 10. Bone plate 69 has an upper surface 71,
2~ a lower surface 73 intended to be adjacent the
patient's bone in use and two side surfaces 75 and 77
connecting surfaces 71 and 73. ~one plate 69 is
provided with for example six identical elongated
through apertures, e g. 79, 80 and 85, for the receipt
of bone screws used to secure the plate to a patient's
bone, e.q. to the outer cortical wall of the femoral
shaft. Some other number (odd or even) of elongated
through apertures than six may be provided in the bone
plate of the invention, if desired. Preferably, the
3~ elongated apertures are alternately offset from the
longitudinal axis of the bone plate (see FIG. 9J in
order to reduce stress concentrations in the secured
bone plate and in the bone and the separation between
the two centermost slots (e.g. the third and fourth
slots in FIG. 9J is greater than the separation between
. "
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~: ~ ~: ; ... , : . .: : :
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. .
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l 328q55
other pairs of adjacent slots. As can be readily seen
in FIG. 10, the width of upper surface 71 is greater
than the width of lower surface 73, side surfaces 75
and 77 are tapered inwardly toward one another in the
S direction from surface 71 to surface 73 ~i.e.
downwardly and inwardly in FIG. 10), and the thickness
T of the bone plate 69 is substantially constant across
the bone plate from side surface 75 to side surface 77.
In the embodiment of FIGS. 9 and 10, bone plate 69
includes two parallel rails 81 and 83 located at the
opposite sides of lower surface 73, which rails extend
along substantially the entire length of plate 69. In
use, only rails 81 and 83 contact the surface of the
patient's bone to minimize interference with bone or
periosteal vascularity.
An important feature of bone plate 69 is that its
transverse cross-sectional dimensions are complementary
to those of the cavity 63 in the elongated plate
portion 45 of the proximal angled side plate 43. Thus,
2~ either end of bone plate 69 can be inserted into cavity
63, but because of the tapered side surfaces of the
bone plate and cavity the bone plate 69 can enter and
be removed from the cavity 63 only by relative axial
movement through the opening of cavity 63 at the free
,5 end 65 of plate portion 45. Separation or joining by
relative movement in the vertical direction is not
permitted and the bone plate 69 cannot rotate with
respect to the proximal angled side plate 43 when it is
inserted within the cavity 63 (see FIG. 17 for a
depiction of the "dovetail" interlock between plate
portion 45 and bone plate 69). When either end of bone
plate 69 is inserted into cavity 63 and the end of the
bone plate abuts shoulder 67, apertures 57 and 59 in
the angled side plate 43 overlie apertures 79 and 85,
respectively, in the bone plate 69. Thus, with the use
:. ~ , . , , - . :: ~ . ::
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l 328q55
of two bone screws passed through the two overlying
pairs of apertures and threaded into the patient's
bone, bone plate 69 can be secured to the elongated
plate portion 45 of side plate 43 in axial alignment in
a stable and secure connection so as to provide an
effective extension of the length of plate portion 45
in vivo.
In a preferred modular system of the invention
three bone plates of varying length of the type shown
1~ in FIG. 9 are provided, having four, six and eight
elongated apertures respectively, for use either
independently or to extend the length of side plates.
Elongated bone plate 69 may also be used by itself
as a conventional bone plate in the treatment of, for
example, diaphyseal femoral fractures. The six
apertures in the plate are elongated to be able to
receive either one or two screws each in use.
Preferably, the upper portions 107, adjacent upper
surPace 71, of the identical apertures are
2~ spherically-rounded concave-upward all the way around
the aperture. These identical spherically-rounded
surfaces are adapted for cooperation with
spherically-headed cortical and cancellous bone screws,
as is discussed below.
~5 Pone plate 69 is preferably slightly curved ~as
viewed in transverse cross-sections such as FIG. 10) to
conform to the shape of the human femoral shaft. In
the preferred embodiment shown in FIG. 10, upper
surface 71 and lower surface 73 are defined in
transverse bone plate cross-sections by arcs of two
concentric circles having a center O, while side
surfaces 75 and 77 are defined by two straight lines
which, when extended, pass through center O and form
together an angle A.,
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1 3~8955
A pair of self-tapping cortical bone screws 89 and
91 which may be included in a modular implant system of
the invention are shown in FIGS. llA and lls. Screws
89 and 91 have identical heads 93 and identical shanks
97 and 99 externally threaded along essentially the
entire shank length, with the single exception that
shank 97 of screw 89 is longer than shank 99 of screw
91. A pair of self-tapping cancellous bone screws 101
and 103 which may be included in a modular implant
1~ system of the invention are shown in FIGS. 12A and 12B.
The heads 93 of screws 101 and 103 are identical to the
heads of cortical screws 89 and 91, while the shanks of
cancellous screws 101 and 103, which are externally
threaded adjacent the free shank end only, are
identical with the single exception that the shank of
screw 101 has a longer unthreaded portion than the
shank of screw 103. Another pair of self-tapping
cortical bone screws 90 and 92 are shown in PIGS. 32
and 32A. These screws are identical to screws 89 and
91 except that a portion of the shanks of screws 90 and
92 is not threaded. As is shown in FIG. 13, an
identical axially-extending recess 95 having parallel
axially-extending walls is provided in each of the
identical heads 93 of screws 89, 91, 90, 92, 101 and
103 for the receipt of a screw-driving instrument (e.q.
a screwdriver). The recess is generally star-shaped in
cross-section, e.q. the generally star-shaped Torx
(TM)-drive cross-section shown in FIG. 13 or the
generally star-shaped cross-section of a Pozidriv (TM~
3U recess. If desired, the cortical and/or cancellous
bone screws may be reduced in one or more steps in
diameter or tàpered towards the free shank end for
increasing grip strength on the neiqhboring femoral
cortex.
~ . r ~
-: ' , : ' ' ' - :
~ . . ~: , ' . " ` . . .
1 328955
Another important feature of the design of screw
head 93 is that the underside 105 of head 93 is
spherically-rounded and substantially complementary
with the spherically-rounded upper portions of the
walls of the screw-receiving apertures in angled side
plate 43 and elongated bone plate 69. FIG. 14 shows
the permitted side-to-side angulation of one of the
four screws of FIGS. llA, 11~, 12A and 12B (shown in
phantom lines) within one of the screw-receiving
apertures (i.e. aperture 80) provided in the bone plate
69. As a consequence of the substantially comple-
mentary spherically-rounded surfaces of head underside
105 and the upper portion 107 of the wall of aperture
80, screw 89 is capable of rotating through an angle of
about 30 in a plane perpendicular to the longitudinal
axis of bone plate 69. Essentially unrestricted
angulation is permitted in a plane parallel to the
longitudinal axis of the bone plate. However, when
bone screw 89 is positioned fully at the end of
2~ aperture 80 unrestricted angulation is permitted in one
direction only in a plane parallel to the longitudinal
axis of the bone plate while only about a 15 rotation
from the vertical is permitted in the opposite
direction in said plane. The radius of the spherically-
rounded surface of the upper portion 61 of the
apertures 55, 57 and 59 in the angled side plate 43 is
equal to the radius in the transverse plane of FI~. 14
of the surface of the upper portion 107 of aperture 80
of bone plate 69. Thus, screws 89, 91, 101 and 103 are
3~ capable of a universal rotation with respect to the
elongated plate portion 45 within a cone having an apex
an~le of about 30 when fully advanced within one of
the apertures 55, 57 and 59. (However, when the angled
side plate is connected with an elongated bone plate
~5 this freedom of rotation is restricted considerably for
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~ 328955
the two screws passing through both plates.) The
substantial allowed angulation of bone screws within an
elongated bone plate or angled side plate enhances
capabilities for adaptation to the fixation of oblique
fractures and complex fracture patterns such as
butterfly fractures. This angulation permits the bone
screws to extend approximately normally to many
fracture lines and serves to increase the number of
bone fragments that can be directly gripped by at least
one screw.
Elongated epiphyseal/metaphyseal implant 1,
proximal angled side plate 43, elongated bone plate 70
having four elongated apertures and a plurality of the
cortical bone screws 89 can be connected together and
secured to a patient's right femur F in the manner
shown in FIGS. 15 to 17 to form an angled side
plate-hip pin assembly with the effective length of the
elongated plate portion of the angled side plate
extended by the elongated bone plate. The implant 1 is
2~ first implanted within a cavity prepared in the
proximal femur, which cavity must be widened adjacent
its open end to accommodate hollow sleeve 47, said
sleeve 47 of side plate 43 is then inserted into the
cavity so that a portion of the cylindrical stem
2S portion 19 of plunger 5 is received in a sliding fit
within the cylindrical bore 53 of sleeve 47, one end of
bone plate 70 is slid into cavity 63 of side plate 43
until it abuts shoulder 67, and the entire assembly is
then secured to the femur F with a plurality of
cortical bone screws 89 passed through apertures in
side plate 43 and bone plate 70. If desired, one or
more conventional fixation pins (e.q. Knowles pins)
unconnected to implant 1 and angled side plate 43 may
also be implanted, with an orientation substantially
parallel to the orientation of implant 1 shown in FIG.
.
; : , , : .
: : - . :.~. . .
i,; ~ . - .- : .
26
~ 328955
16. ~one plate 70 can, of course, be omitted from the
assembly of F~G. 16 if the length of ~late portion 45
is sufficient without extension in a particular
surgical situation.
A femoral intramedullary rod 109 which may be
included in a modular implant system or kit of the
invention is shown in side elevational views in FIGS.
19 and 20 as viewed in perpendicular directions. Rod
109 has a proximal end 111 and a distal end 113 and a
pair of transverse through bores 115 adjacent distal
end 113 to receive bone screws 90. One or two through
bores 116 to receive locking bone screws may also be
included adjacent proximal end 111. Rod 109 has a
distal end portion 117 and a straight proximal end
portion 119. As is shown in FIG. l9, rod 109 has a
slight bow, which is intended to lie in the anterior-
posterior plane of the femur after implantation; no
such bow is exhibited in FIG. 20, since rod 109 is
intended to be straight in the lateral-medial plane
after implantation. The transverse cross-section of
rod 109 is shown in FIG. 21. This cross-section has a
closed profile, with the outer periphery of the
cross-section being a plurality of (~ ~ six~ smoothly
rounded peaks ~e.q. 121), all terminating on the same
first circle, connected by an equal number of smoothly
rounded valleys (e.q. 123), all bottoming on the same
second circle concentric with and of smaller diameter
than said first circle. The provision of these
alternating peaks and valleys greatly enhances the
3~ stability of the implanted rod 109 against axial
rotation with respect to the patient's bone, while
their smoothly rounded nature greatly reduces the
possibilities for damaging the bone of the
intramedullary wall. Furthermore, the alternately
raised and lowered outer peripheral rod configuration
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1 328955
shown in FIG. 21 provides for extensive
re-vascularization of the bone tissue of the
intramedullary canal wall following reaming. FIG. 21
also shows that rod 109 is axially cannulated, with an
axial bore 125 extending from the distal tip 127 of
hollow rod 109 to the proximal tip 129 of the rod.
A diametrical slot 120 is provided at proximal tip 129
for engagement with appropriate insertion and
extraction tools.
An elongated connection piece 139, locking screw
141 and locking shoe 142 for connecting an epiphyseal/-
metaphyseal implant 1 to intramedullary rod 109
adjacent to the proximal end 111 of rod 109 to form a
Y-nail type of assembly are shown in FIGS. 23 and 24.
Connection piece 139 is provided at one end with an
elongated cylindrical cavity 143 aligned with the
longitudinal axis of piece 139 and adapted to receive
the free end of stem portion 19 of plunger 5 of implant
1 in a sliding fit. Connection piece 139 is also
provided with a cylindrical through bore 145 disposed
at an oblique angle of about 135 with respect to said
longitudinal axis, and an elongated partially
countersunk and partially internally-threaded bore 147
aligned with said longitudinal axis at the end of the
;; 25 elongated connection piece 139 opposite to cavity 143.
Bore 147 is adapted to receive locking screw 141 and
locking shoe 142, and both bore 147 and cavity 143 open
into through bore 145. The diameter of through bore
145 is just slightly greater than that of the maximum
cross-sectional dimension of the proximal end portion
119 of intramedullary rod 109 so that proximal end
portion 119 can be received in a close sliding fit
within through bore 145 permitting rotational and
translational adjustment of the connection piece 139
3~ with respect to the intramedullary rod 109. Connection
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1 328955
piece 139 and intramedullary rod 109 can be securely
locked against relative translational and rotational
movement by screwing locking screw 141 forward in the
partially threaded bore 147 behind the locking shoe 142
until the leading surface 144 of locking shoe 142 very
firmly presses against the surface of proximal end
portion 119, and then unlocked again if desired simply
by unscrewing screw 141. The leading surface 144 of
locking shoe 142 has a grooved contour adapted to fit
closely and mesh with the splined external contour of
rod 109, thereby enhancing the secure locking of rod
109 to the connection piece 139. Locking screw 141 and
locking shoe 142 are assembled together in use, e.q. by
a captured thread or staked head connection, to cause
withdrawl of shoe 142 when screw 141 is unscrewed while
permitting independent relative rotation between these
two element during screwing and unscrewing of screw
141.
In the alternative embodiment shown in FIG. 22,
2~ a hollow sleeve 131 having a smooth cylindrical outer
surface is detachably secured to the exterior of the
proximal end portion 119 of intramedullary rod 109
(havin~ the fluted cross-section of FIG. 21) by means
of a locking screw 135 having a head and an externally
~5 threaded shank fitted through a centrally-disposed
opening in the top wall of sleeve 131 and threaded into
an internally-threaded centrally-disposed bore 137 at
the top of rod lO9. An advantage of the embodiment of
FIG. 22 is that the diameter of the straight proximal
3~ end of rod 109 is effectively increased above that of
the maximum transverse dimension in the transverse
cross-section of FIG. 21. The hollow sleeve 131 should
extend distally at least to the point of maximum
applied bending moment in normal use, which point of
maximum bending moment is usually in the sub-
., "
.
29 ~ 328955
trochanteric region of the femur, but not all the way
to the midway point along the length of rod 109 between
the distal and proximal tips 127 and 129 of the rod.
When hollow sleeve 131 is used, the contour of the
S leading surface of locking shoe 142 should be adapted
accordingly, or alternatively, the locking shoe can be
eliminated and the locking screw used alone.
Intramedullary rod 109, connection piece 139,
locking screw 141, locking shoe 142 and a bone implant
1 can be connected together in the manner shown in FIG.
25 to form a Y-nail type of assembly in a femur F, with
implant 1 and piece 139 forming together the elongated
cross-member of the Y-nail. The epiphyseal~metaphyseal
implant 1 is first implanted into a cavity prepared in
the proximal femur, which cavity must be widened
adjacent its open end to accommodate the connection
piece 139. Piece 139 is then advanced into the
prepared bone cavity and oriented 50 that a portion of
stem portion 19 of plunger 5 is received in a sliding
2~ fit within cavity 143 and through bore 145 is in
- approximate alignment with the femoral intramedullary
canal. Rod 109 is advanced distally through an opening
prepared by conventional means in the proximal femur
wall and through the through bore 145 in piece 139
until the distal end portion 117 of rod 109 is in the
distal femur and the proximal end portion 119 of the
rod 109 is within the through bore 145. The
disposition of rod 109 with respect to the femur F and
connection piece 139 is then carefully adjusted to the
3~ desired disposition, and connection piece 139 is then
locked to intramedullary rod 109 by means of the
locking screw 141 and locking shoe 14~. If desired
a cortical bone screw 90 of the type shown in FIG. 32A
o~ large shank length can be inserted by conventional
methods through one or both of the transverse bores 115
: . ' `'~ ~ ',.~ ........... ' . `
'~ ' ' ' , " ""' ' . " ' ' :. ''"
- . .'
.
30 ~ 328955
to lock the rod 109 to the distal femur. Also, cap
screw 135 may be screwed into bore 137, even when
sleeve 131 is not being used, to prevent bone ingrowth
into the threads in bore 137.
It is contemplated that a connection piece similar
to piece 139 could be used, if desired, to connect an
epiphyseal/metaphyseal implant similar to implant 1 to
the distal end portion 117 of intramedullary rod 109,
with the epiphyseal/metaphyseal implant residing in the
1~ distal condylar region of the femur and being
substantially perpendicular to said portion 117. In
such a case the through bore of the connection piece
analogous to through bore 145 in piece 139 would be
substantially perpendicular to the longitudinal axis of
the connection piece.
A distal angled side plate 149 which may be
included in a modular implant system or kit of the
invention is shown in FIGS. 26 and 27. Distal angled
side plate 149 includes an elongated plate portion 151
2u adapted to be secured to the outer cortical wall of the
distal femoral shaft and an integral hollow sleeve 153
extending from one end of plate portion 151. As is
shown in FIG. 27, the plate portion 151 is slightly
angulated in the vicinity of line R in order to
2j accommodate the commencement of the anatomical bulge of
the lateral distal femur. The elongated plate portion
151 has an upper surface 155 and a lower surface 157
intended to be adjacent the patient's bone in use,
while the hollow slee~e 153 is provided with a
longitudinal cylindrical through bore 159 extending
from upper surface 155 to the free end of hollow sleeve
153. As shown in FIG. 27, the elongated plate portion
151 and hollow sleeve 153 are substantially
perpendicular so that hollow sleeve 153 is adapted to
~5 extend into the distal condylar region of the femur
.....
- : ,. ;
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:
,
31 1 328955
when elongated plate portion 151 is secured to the
outer cortical wall of the adjacent distal femoral
shaft. Through bore lS9 is dimensioned to receive a
portion of the stem portion 19 of the plunger 5 of an
S elongated epiphyseal/metaphyseal implant 1 in a sliding
fit. The lower surface 157 is slightly curved in
transverse cross-section in a similar manner as shown
in FIG. 8 (for the proximal side plate 43) to conform
to the outer cortical wall of a distal femur.
Three circular through apertures 161, 163 and 165
are provided in plate portion lSl for the receipt of
three bone screws (e.g. cortical screw 89), one in each
aperture. These three apertures are staggered with
respect to the longitudinal axis of plate portion 151
lS ~see FIG. 26) in order to reduce stress concentrations
in the secured plate portion and in the bone.
Apertures 161, 163 and 165 are identical respectively
to apertures SS, 57 and S9 in the proximal angled side
plate 43. The distal angled side plate 149 is also
2~ provided with an elongated cavity 167 formed in the
lower surface 157 of plate portion lSl. Cavity 167 is
identical to cavity 63 in the proximal angled side
plate 43. Thus, cavity 167 is adapted to receive
either end of elongated bone plate 69 in a "dovetailn
interlocked sliding fit (see FIG. 17), and when the end
of the bone plate abuts shoulder 169 apertures 163 and
165 overlie the two terminal apertures, e q. apertures
79 and 85 respectively, in the bone plate 69.
The distal angled side plate 149, an elongated
epiphyseal/metaphyseal implant 1 and a plurality of the
cortical bone screws 89 can be connected together and
secured to a patient's femur F in the manner shown in
FIG. 28 to form a distal side plate-pin assembly with
the effective length of the elongated plate portion of
the side plate extended by the elongated bone plate.
.
. '. :.', '
32 ~ 3~89 55
The preferred surgical procedure is analogous to the
one described above with regard to the assembly of
FIGS. 15 and 16. ~30ne plate 69 can, of course, be
omitted from the assembly of FIG. 28 if the length of
S plate portion 151 is sufficient without extension in a
particular surgical situation.
A distal buttress plate 171 of the invention
adapted to be secured to the outer cortical wall of the
lateral distal femur is shown in FIGS. 29 and 30.
1~ Buttress plate 171 includes a relatively flat elongated
proximal portion 173 adapted to be secured to the
lateral distal femoral shaft and a three
dimensionally-contoured distal portion 175 designed to
replicate the mean geometry of the lateral femoral
1~ condyle of adult humans. The distal portion 175
includes a generally rounded head 177 at the distal end
of plate 171, a generally widened body 179 having a
greater maximum width than both head 177 and proximal
portion 173, and a neck 181 having a minimum width W
2u substantially smaller than the maximum widths of head
177 and body 179. As viewed in transverse
cross-sections, the lower surface of the distal
buttress plate 171 is contoured along its entire length
to conform to the outer cortical wall of the distal
2S femur.
Distal buttress plate 171 is adapted to be secured
to the outer cortical wall of the lateral distal femur
by means of bone screws received in apertures in the
plate. Thus, three circular through apertures 183, 185
and 187 are provided in proximal portion 173 for the
receipt of three bone screws ~e.q. cortical screw 89),
one in each aperture. These three apertures are
staggered with respect to the lonqitudinal axis of
proximal portion 173 ~see FIG. 29), and are identical
respectively to apertures 55, 57 and 59 in the angled
,
- , . .
.
~, , ,~ , . : .....
:
.
.,
~ 3289 55
side plate 43. Also, an elongated aperture 189 is
provided in head 177 and two elongated apertures 191
and 193 are provided in body 179, one on each side of
body 179. Each of apertures 189, 191 and 193 is
substantially identical to the apertures in the
elongated bone plate 69 and thus are each configured to
receive two (or one, if only one is desired) bone
screws having a head 93 and permit the universal
angulation of said screws when fully advanced in the
aperture.
Furthermore, it is often highly desirable to use a
distal buttress plate in conjunction with a pair of
fracture reduction lag screws extending across the
distal condylar region of the femur. Such lag screws
are screwed fully into the bone before the distal
buttress plate is implanted and thus cannot practically
be passed through the plate. An important feature of
distal buttress plate 171 is that the distal portion
175 thereof is configured in such a manner that spaces
23 outside the periphery of plate 171 are left against ,
neck 181 for the accommodation of two fracture
reduction lag screws, extending across the distal
condylar region of the femur, on the two sides of neck
181. These two lag screws are shown in phantom in FIG.
29 as elements 195 and 197.
Finally, the distal buttress plate 171 is also
provided with an elongated cavity 199 formed in the
lower surface of the proximal portion 173. Cavity 199
is identical to, and is adapted to serve in the same
bone plate-"dovetail" interlocking capacity as, cavity
63 in the angled side plate 43 and cavity 167 in the
angled side plate 149. When the end of bone plate 69
inserted into cavity 199 abuts the shoulder 201 of the
cavity, apertures 185 and 187 overlie the two terminal
,
34
1 328q55
apertures, e.g. apertures 79 and 85 respectively, in
the bone plate 69.
Distal buttress plate 171, elongated bone plate
69, a plurality of cortical bone screws such as screw
89 and a plurality of cancellous bone screws such as
screw 101 can be connected together and secured to a
patient's femur F in the manner shown in FIG. 31.
First, two lag screws (not shown in FIG. 31) are fully
implanted in the distal condylar region, if desired, to
1~ reduce a fracture in said region. These implanted lag
screws are positioned so that they lie generally in the
lateral-medial plane and are spaced so that they will
lie in close proximity to the two opposite sides of the
neck 181 of portion 175 (see F~G. 29). The distal
buttress plate 171 is then secured to the lateral
femur, with neck 181 fitting between the two previously
implanted fracture reduction lag screws, by means of
bone screws 101 passing through apertures 189, 191 and
193 (one or two screws can be passed through each of
apertures 189, 191 and 193, as desired) and a bone
screw 89 passed through aperture 183. ~one plate 69 is
then slid into cavity 199 until its end abuts shoulder
201 and bone screws 89 are screwed to the femur F
through apertures 185 and 187. Finally, bone screws 89
2S are screwed to the femur F through some or all of the
four apertures of bone plate 69 remaining outside of
~; the cavity 199. Distal buttress plate 171 can, of
course, be implanted without bone plate 69 if the
length of the proximal portion 173 is sufficient
without extension for a particular surgical situation.
. . :
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': .
~' '-
. .
