U.S. patent application number 15/183362 was filed with the patent office on 2016-10-06 for bone plate system for repair of proximal humeral fracture.
The applicant listed for this patent is Ascension Orthopedics, Inc.. Invention is credited to Linda C. Cooper, William B. Geissler.
Application Number | 20160287297 15/183362 |
Document ID | / |
Family ID | 45445955 |
Filed Date | 2016-10-06 |
United States Patent
Application |
20160287297 |
Kind Code |
A1 |
Geissler; William B. ; et
al. |
October 6, 2016 |
Bone Plate System for Repair of Proximal Humeral Fracture
Abstract
A bone plate system for repair of a proximal humeral head
fracture, which includes a fixation plate having a main body and a
depending alignment flange, a plurality of elongated compression
screws to extend through the intact humeral head into the cortical
bone of the fractured portion and a cover plate. With the fixation
plate in place, fastened to the humerus, the cover plate is in turn
fastened to the fixation plate and provides a defined amount of
clearance in a region adjacent the heads of the compression screws
to allow measured back-out of the screws upon settling of the
fractured bone portion at the fracture site.
Inventors: |
Geissler; William B.;
(Brandon, MS) ; Cooper; Linda C.; (Austin,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ascension Orthopedics, Inc. |
Austin |
TX |
US |
|
|
Family ID: |
45445955 |
Appl. No.: |
15/183362 |
Filed: |
June 15, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13346006 |
Jan 9, 2012 |
9387020 |
|
|
15183362 |
|
|
|
|
61431258 |
Jan 10, 2011 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/8061 20130101;
A61B 17/8042 20130101; A61B 17/8057 20130101; A61B 17/8625
20130101 |
International
Class: |
A61B 17/80 20060101
A61B017/80; A61B 17/86 20060101 A61B017/86 |
Claims
1-11. (canceled)
12. A bone plate system for repair of a fracture of a major bone of
the skeleton of a vertebrate, which system comprises a fixation
plate having a main body including a head section and a stem
section, which plate includes (a) a plurality of holes for passage
therethrough of screws for fastening said fixation plate to the
surface of an intact bone within which a fracture has occurred to
create a fractured separate bone portion thereof and (b) a
plurality of holes in said head section through which elongated
compression screws can be passed which will extend through drilled
passageways in the bone and screw into cortical bone of said
fractured separate portion thereof, a plurality of fastening
screws, a plurality of said elongated compression screws having
threaded distal end portions, and an integral stabilization flange
which depends from said head section of said fixation plate and is
aligned at an angle of about 70 degrees to 90 degrees thereto,
which flange allows said fixation plate to be precisely aligned on
the intact bone portion to facilitate precise placement of said
elongated compression screws.
13. A bone plate system according to claim 12 wherein said
stabilization flange includes a longitudinally extending elongated
hole.
14. A bone plate system according to claim 12 wherein said holes
through which the compression screws pass are aligned with parallel
centerlines.
15. A bone plate system according to claim 12 wherein said holes
through which the compression screws pass have countersinks which
form outer portions thereof.
16. A fixation plate for use in the repair of a fracture of a major
bone of the skeleton of a vertebrate, which plate comprises a main
body including a head section and a stem section a plurality of
holes in said head and stem sections for passage therethrough of
screws for fastening said fixation plate to the surface of an
intact bone within which a facture has occurred to create a
fractured separate bone portion thereof, a plurality of holes in
said head section through which elongated compression screws can be
passed which will extend through drilled passageways in the bone
and screw into cortical bone of said fractured separate portion
thereof, and an integral stabilization flange which depends from
said head section and is aligned at an angle of about 70 degrees to
90 degrees thereto, which flange allows said fixation plate to be
precisely aligned on an intact bone portion to facilitate precise
placement of the elongated compression screws.
17. The fixation plate of claim 16 where said stabilization flange
includes a longitudinally extending elongated hole.
18. The fixation plate of claim 17 wherein said hole through which
the compression screws pass are aligned with parallel
centerlines.
19. The fixation plate of claim 18 wherein said holes through which
the compression screws pass have countersinks which form outer
portions thereof.
20. The fixation plate of claim 19 in combination with a cover
plate which obscures the countersinks and is spaced therefrom to
create a gap of about 2 to 6 mm from an inner surface of the cover
plate.
Description
[0001] This application claims priority from U.S. Provisional
Patent Application Ser. No. 61/431,258, filed Jan. 10, 2011, the
disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to orthopedic products for
repair of fractured bones and more particularly to bone plate
systems for repair of a major bone of the skeleton of a vertebrate,
such as a proximal humeral head fracture.
BACKGROUND OF THE INVENTION
[0003] Fractures of the proximal humerus can occur in patients of
any age; however, these fractures have been found to occur more
frequently in older patients, particularly elderly females who may
suffer from osteoporosis. Such fractures usually occur in
predictable fracture patterns and are commonly caused by falls
where an arm was outstretched in an attempt to break the fall. Due
to the compressive and varus forces about the shoulder, there is a
tendency for the humeral head fragment to collapse in varus and
settle distally.
[0004] Treatment of such fractures has, in past decades, tended to
use a screw and fixation plate system where the fractured portion
of the humeral head is first realigned, if displaced, and the
proximal end of the humerus is then stabilized by multiple screws
that attach a fixation plate to the surface of the humerus opposite
from the surface where the fracture has occurred. Use of such
plates for this purpose is well known and is shown, for example, in
U.S. Pat. No. 7,604,657 and Published Application No. 2009/0326591.
Such fixation or bone plates usually include a variety of holes,
some of which are dedicated to elongated compression screws for
passage through the head of the humerus into the fractured segment,
whereas other holes are dedicated for the passage of a K-wire for
alignment purposes, or for sutures for use in compressing the
fractured bone part against the humerus, or for screws to securely
mount the plate to the cortical bone of the humerus.
[0005] A wide variety of mechanisms have been developed for locking
these elongated compression screws to the fixation plate so as to
prevent incidental subsequent movement of the screws that might
result in screw back-out, which has been felt to be undesirable
toward retaining the fractured section of the humeral head in
alignment. Some of these locking systems have used a variety of
inserts for positioning within the cavities in the fixation plate
where the heads of the elongated screws would reside, such as those
shown in U.S. Pat. Nos. 5,578,034; 6,695,846; 7,004,944 and
7,273,481, designed to lock the heads. Alternative solutions have
resulted in employment of a variety of plates or detents which are
fastened in some manner so as to abut the heads of the elongated
screws and thus positively block any back-out of the screw heads
within the fixation plate; examples of such are shown in U.S. Pat.
Nos. 4,794,918; 6,406,478; 6,413,259; 6,652,525 and 7,060,067, and
in Published Patent Application 2006/0122605.
[0006] Over the years, it has been found that, during post-surgery,
the fractured portion of the humeral head may frequently settle
upon the closing of the fracture gap, and the amount of such
settling can often be significant. The result has often been the
protrusion of the pointed tips of the elongated compression screws
through the cortical bone of the fractured portion, resulting in
the emergence of these pointed tips in the articular surface of the
humerus.
[0007] Effective locking plate systems particularly suited for the
treatment of proximal humeral head fractures which avoid potential
screw tip protrusion into the articular surface of the humeral head
have accordingly been sought.
BRIEF SUMMARY OF THE INVENTION
[0008] A bone plate system is provided which includes a fixation
plate having a variety of holes, including holes for elongated
threaded compression screws that will extend into the cortical bone
of the fractured portion of a humeral head and holes for the
passage of other screws to fasten the fixation plate to the
cortical bone of the humerus which it abuts, and a cover plate.
When the cover plate is installed onto the implanted fixation
plate, its interior surface is spaced a precise distance from the
heads of the elongated compression screws to provide a clearance
region; this region provides space into which a defined extent of
screw back-out is allowed.
[0009] The system design is such that parallel, slightly oversize
holes are drilled through the intact humeral head, which holes have
a diameter such that the elongated compression screws can freely
pass therethrough so as to reach and enter the cortical bone of the
fractured portion, into which they will become threadably
connected. With the elongated compression screws threaded into the
cortical bone of the fractured portion and with the fixation plate
securely fastened to the humerus via a plurality of fastening
screws, the fracture portion is pulled into contact with the intact
humeral head. The cover plate is then installed; this plate is
proportioned to fit over and envelop the region wherein of the
heads of all of the elongated compression screws lie. The cover
plate is recessed to provide a clearance of between about 2 and
about 6 mm between the end faces of the heads of the compression
screws and the interior surface of the cover plate. As a result,
when settling of the fractured portion of the humeral head occurs
as a result of its compression against the major portion of the
humerus, some measured back-out of the compression screws is
allowed; the heads may move longitudinally in the clearance region
for 2-6 mm before making contact with the interior surface of the
cover plate. During such movement, sliding engagement of the shanks
of the compression screws within the walls of the holes of the
fixation plate through which the compression screws pass continues
to stabilize the secure connection of the fractured portion to the
remainder of the intact humerus, as the fixation plate is itself
securely affixed to the humerus by fastening screws.
[0010] In one particular aspect, the invention provides a bone
plate system for repair of a fracture of a major bone of the
skeleton of a vertebrate, which system comprises a fixation plate
having a main body which includes (a) a plurality of holes for
passage therethrough of screws for fastening said fixation plate to
the surface of an intact bone within which a fracture has occurred
to create a fractured separate bone portion thereof and (b) a
plurality of holes through which elongated compression screws can
be passed which will extend through drilled passageways in the bone
and screw into cortical bone of said fractured separate portion
thereof, a plurality of fastening screws, a plurality of said
elongated compression screws having threaded distal end portions, a
cover plate which, when installed as a part of the implanted bone
plate system, has an inner surface that is spaced a defined
distance from the heads of said elongated compression screws to
provide a gap between said inner surface and the outer surface of
said fixation plate, and fastening means for securing said cover
plate to said fixation plate with said inner surface spaced between
about 2 and about 6 mm from heads of said elongated screws so that,
upon compression of said fractured portion and said bone, pointed
tips of said threaded end portions of said elongated compression
screws remain connected within cortical bone of said fractured bone
portion while said heads of said elongated compression screws can
move longitudinally into the gap between said fixation plate outer
surface and said cover plate inner surface.
[0011] In another particular aspect, the invention provides a bone
plate system for repair of a fracture of a major bone of the
skeleton of a vertebrate, which system comprises a fixation plate
having a main body including a head section and a stem section,
which plate includes (a) a plurality of holes for passage
therethrough of screws for fastening said fixation plate to the
surface of an intact bone within which a fracture has occurred to
create a fractured separate bone portion thereof and (b) a
plurality of holes in said head section through which elongated
compression screws can be passed which will extend through drilled
passageways in the bone and screw into cortical bone of said
fractured separate portion thereof, a plurality of fastening
screws, a plurality of said elongated compression screws having
threaded distal ends portions, and an integral stabilization flange
which depends from said head section of said fixation plate and is
aligned at an angle of about 70 degrees to 90 degrees thereto,
which flange allows said fixation plate to be precisely aligned on
the intact bone portion to facilitate precise placement of said
elongated compression screws.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is an exploded perspective view of a portion of a
bone plate system embodying various features of this invention
which includes a humeral head fixation plate, four elongated
compression screws, a cover plate, and two locking screws for
securing the cover plate to the fixation plate.
[0013] FIG. 2 is a side view of the bone plate system of FIG. 1
shown with the elongated compression screws and the cover plate in
their operative positions.
[0014] FIG. 3 is a front view of the bone plate system shown in
FIG. 2.
[0015] FIG. 4 is a cross sectional schematic view taken along a
line through the center of each of the holes showing the bone plate
system of FIG. 1 implanted in a fractured humeral head.
[0016] FIG. 5 is a fragmentary view, enlarged in size, of a portion
of the bone plate system shown in FIG. 4, emphasizing the
relationship between the heads of the elongated compression screws
and the cover plate as such might exist immediately following
orthopedic surgery to repair a fractured humeral head.
[0017] FIG. 6 is a side view of an alternative use of a humeral
head fixation plate of the general type shown in FIG. 1 in
combination with four elongated compression screws of different
design and 8 fastening screws assembled therewith, illustrating the
orientation in which they might reside when used to treat a
fracture of the proximal humerus.
[0018] FIG. 7 is a front view of the bone plate system shown in
FIG. 6 with the screws 23a removed.
[0019] FIG. 8 is a rear view of the bone plate system shown in FIG.
6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] FIG. 1 shows a bone or fixation plate 11 designed
particularly for treating a fracture of the proximal humerus, which
is made of rigid material such as a biocompatible metal or metal
alloy, e.g. titanium, stainless steel, titanium-aluminum-niobium
alloys, etc. The fixation plate 11 has a main body 12 which
comprises a head section 13 and stem section 15. As best seen in
FIG. 2, the fixation plate 11 is contoured so as to follow the
general shape of the proximal end of the humerus, with the head
section 13 lying juxtaposed with a surface of the humeral head and
with the stem section 15 juxtaposed with a central elongated
section of the humerus.
[0021] The fixation plate 11 is designed for treatment of a
fracture of the humerus 17 where a portion 19 of the head of the
humerus has been fractured and separated from the remainder of the
bone. FIG. 4 depicts such a repair of a humeral head fracture
showing the proximal end region of the humerus 17 and the fractured
portion of the humeral head 19 as it might be repaired using a bone
plate system embodying features of the present invention. The head
section 13 of the fixation plate 11 includes a plurality of holes
21, in this case four, through which elongated compression screws
23 are passed; these four screws are designed to threadably connect
to the cortical bone of the detached or fractured portion 19 of the
humeral head as depicted in FIG. 4. To afford good purchase which
assures that the fractured portion can be pulled into tight contact
with the surface of the intact humeral head, it is important that
the threaded ends are seated deeply into the cortical bone so their
end tips are close to the outer surface.
[0022] The fixation plate 11 also contains a plurality of holes for
fastening screws to affix the plate to the surface of the intact
humerus. Four holes 25 are located in the stem 15 distally of the
four holes 21 for the compression screws, and four more holes 27
are located in the head section 13 proximally of the four holes 21.
In the illustrated embodiment, these holes 25 and 27 will
accommodate 8 fastening screws 29 (see FIG. 6) that will be screwed
into cortical bone of the humerus 17 to securely fasten the
fixation plate 11 thereto. The holes 25 and 27 may be optionally
threaded as depicted.
[0023] The fixation plate 11 also carries a stabilizing flange 31
which depends from the stem section 15 of the plate and is aligned
at an angle of between about 70 degrees and 90 degrees to the main
body 12 of the plate. This flange 31 has a longitudinally extending
elongated hole or slot 33 and is designed to lie adjacent the side
surface of the humerus 17 to which it can be secured, if desired,
by a screw or other fastener inserted through the elongated hole
33. This flange 31 and the elongated hole 33 may cooperate to
effect initial precise positioning of the plate 11 upon the surface
of the intact humerus.
[0024] The fixation plate also includes various other holes, such
as holes 34a, through which K-wires may be passed for use during
the implantation of the bone plate system by the surgeon, and holes
34b through which other fasteners or sutures can be passed. In
particular, the fixation plate 11 includes two small threaded holes
35, which are located and created to receive two lock screws 37
that are used to mount a cover plate 39 to the exterior surface of
the fixation plate 11 once implantation of the plate is essentially
completed.
[0025] The cover plate 39 is shaped and proportioned to fit atop
and obscure the four holes 21 that receive the elongated
compression screws 23 that are used to reunite the fractured
humeral head portion 19 to the remainder of the intact humerus 17.
The embodiment of the cover plate 39 shown includes two countersunk
openings 41 which receive the cover plate lock screws 37 and are
aligned with the two threaded holes 35 in the fixation plate. The
exterior surface of the cover plate 39 is essentially smooth except
for the two countersunk openings 41, and its interior surface is
recessed (see FIG. 5) so that there is an outer rim 43 which
extends around the periphery of the cover plate that surrounds an
essentially flat, central interior surface region 45. The rim 43
and the flat surface 45 form a boundary of a recess 47 having a
depth of between about 2 to 6 mm, and preferably between 3 and 5
mm, e.g. between about 3 to 4 mm.
[0026] As best seen perhaps in FIG. 5, the four holes 21 through
which the elongated compression screws are passed may be optionally
threaded, if desired for a purpose to be explained hereinafter. In
any respect, the holes 21 through the fixation plate are preferably
aligned so as to have four parallel centerlines; thus, the four
compression screws 23 will extend parallel to one another through
four parallel passageways 51 drilled in the intact humerus 17,
through the spongy cancellous bone, traversing the fracture site
and enter the cortical bone at the surface of the fractured portion
19 of the humeral head. The compression screws 23, as seen in FIGS.
1 and 5, have socket heads 53 which may, for example, be of smooth,
generally hemispherical or ovoid exterior shape. The distal ends 55
of the compression screws 23 are threaded; however, the shanks 57
of the screws are preferably smooth and of a diameter similar to
that of the threaded portion or slightly greater than the threaded
portion. Prior to installation, four parallel passageways 51 are
drilled through intact humeral head using an appropriate jig or
guide; these four parallel passageways are slightly oversized so
there will be no direct frictional connection of the shanks 57 of
the compression screws to the bone of the intact portion of the
humerus 17. The walls of the outer portions of the four holes 21,
which may be thought of as countersinks 61, may optionally be
threaded, and are sized such that the shank 57 of each screw is
relatively tightly constrained by the wall surface of an inner or
neck portion of the hole where the hole opens onto the interior
surface of the fixation plate; however, the generally hemispherical
surface of the head 53 is juxtaposed within the threaded
countersink region 61 which is proportioned so that the head can
rotate freely. All four heads 53 of the compression screws 23
originally reside entirely within the confines of the countersunk
four holes 21, as seen in FIG. 5, and the pointed end tips 59 are
seated in the cortical bone of the fractured portion 19 as shown in
FIG. 4. Although compression screws 23 having socket heads are
preferred, Philips head screws or screws having heads of other
design might alternatively be employed.
[0027] Once the four compression screws 23 are in place with the
threaded ends 55 extending into the cortical bone of the fractured
portion 19 of the humeral head, and with the fracture site in
alignment as shown in FIG. 4, the four screws 23 arc tightened so
as to pull and compress the fractured portion 19 against the intact
humerus 17; then the cover plate 39 is fastened to the fixation
plate 11 so as to cover socket heads 53 and obscure the four
openings 21. Fastening of the cover plate 39 to the fixation plate
11 can be done by any appropriate securing mechanism. In the
illustrated embodiment, such fastening is simply effected by
threading two lock screws 37 through countersunk openings 41 in the
cover plate 39 into the two aligned, threaded holes 35 in the
fixation plate 11 to tightly affix the cover plate in the
orientation shown in FIGS. 3, 4 and 5.
[0028] As best seen in enlarged cross sectional view FIG. 5, the
recess 47 provided within the cover plate 39 spaces the interior
surface 45 of the cover plate a precise desired distance from the
nearest point of approach of the flat front surface of each of the
four socket-head compression screws 23. It has been shown that a
minimum distance of at least about 2 mm should be provided for the
gap between the flat interior surface 45 and the screw heads 53,
and more preferably the depth of the gap is not greater than about
5 or 6 mm.
[0029] As previously indicated, it is important that the elongated
compression screws 23 extend sufficiently deeply into the cortical
bone of the fractured portion 19 of the humeral head to provide
adequate purchase to assure compression and ultimate fixation at
the fracture site that will result in the repair of the fractured
humeral head. However, such an orientation creates the potential of
extrusion/protrusion of the pointed tips 59 of the compression
screws 23, out of the fractured portion 19 and into the articular
surface of the humerus, when the heads of the screws 23 are rigidly
clamped or otherwise affixed within the openings of the fixation
plate 11, as has been the general practice. In contrast, when using
the embodiment shown in FIGS. 1 to 5, should settling occur as a
result of further compression at the fracture site, because there
is no direct, rigid connection of the compression screws 23 to the
bone of the intact humerus, or to the plate 11, the fixation plate
11 would not prevent longitudinal movement of the screws 23.
Instead, the design of the cover plate/fixation plate combination
is such as to permit measured longitudinal movement of the heads 53
of the compression screws 23 in the region of the holes 21 and the
recess 47 within the cover plate 39 for at least a minimum distance
of about 2 mm and more preferably for a distance of about 3 to
about 5 mm. This arrangement positively guards against extrusion of
the compression screw pointed ends 59 into the articular surface of
the humeral head; at the same time, it retains adequate stability
of the overall repair through confinement of the four heads 53
within the holes 21 and through the sliding contact between the
shank 57 of each of the four screws and the circular wall of each
hole where it leads to the inner surface of the fixation plate
11.
[0030] As an example of such a repair of a proximal humerus
fracture, a fixation plate 11 of the appropriate size would be
chosen and fitted to the humerus 17, and one or more K-wires might
be installed. A guide might then be substituted for the plate to be
implanted, and four parallel passageways 51 drilled in the humerus
17 that are just slightly oversized relative to the shanks 57 of
the compression screws 23 to be used. Thereafter, with the
fractured portion 19 of the humerus 17 likely sutured to the head
of the intact humerus, the fixation plate 11 is positioned on the
intact humerus assisted by the K-wires, and the stabilizing flange
31 is juxtaposed with the lateral surface of the humerus so that a
screw (not shown) can optimally be inserted through the center of
the elongated hole 33. Final positioning of the plate 11 is then
facilitated by movement guided by the elongated hole 33 in the
flange 31, and the four compression screws 23 are passed through
the four holes 21. Using self-tapping threads, the threaded
portions 55 of the screws 23 are threaded into the fractured
humeral portion 19. These four socket-head screws 23 are then
tightened to align and compress the fractured portion 19 with the
remainder of the intact humeral head across the fracture site from
the position shown in FIG. 4, and so as to extend deeply into the
cortical bone, terminating near the outer articular surface.
[0031] Once this reconnection of the fractured portion 19 to the
humeral head is completed, the fixation plate 11 would be fastened
to the humerus 17 by drilling holes and installing eight fastening
screws 29 through the holes 25 and 27. Any K-wires would then be
removed if not already removed. If not earlier inserted, a further
fastener might then be inserted through the elongated hole 33 in
the lateral flange 31. With the fixation plate 11 thus securely
fastened to the intact humerus, a final tightening of the four
compression screws 23 might be made. Then the cover plate 39 would
be installed using the two locking screws 37 to fasten it in place
where it overlays and obscures the heads 53 of the four elongated
compressions screws.
[0032] Thereafter, should settling occur between the fractured
portion 19 and the intact humerus 17, movement of the screws will
be along the path of least resistance; in other words, the shanks
57 of the compression screws 23 can slide longitudinally within the
humerus with the socket-containing heads 53 moving longitudinally
in the holes 21 into the minimum gap or recess 47 of at least about
2 mm. It has been found that the provision of such a gap is
sufficient to preclude protrusion of the pointed tips 59 of the
compression screws 23 out of the fracture portion in the articular
region, which occurrence would likely result in the need for a
further operation to correct.
[0033] As previously mentioned, the holes 21 of the fixation plate
may be optionally threaded. Shown in FIGS. 6, 7 and 8 is a
generally similar fixation plate 11a wherein use is made of such
threaded holes 21. Should, for whatever reason, a surgeon feel that
use of the bone plate system of FIGS. 1-5 might not be desired for
repair of a particular fracture, the fixation plate 11a might be
used with four elongated compression screws 23a that are threaded
for their entire length. Such screws 23a might be affixed to the
plate 11a by any suitable locking mechanism known in the art in
combination with the threads in the holes 21. FIG. 6 shows such an
arrangement where four such compression screws 23a, that are
parallel to one another, are shown extending through the four holes
21 aligned so they would connect to a fracture portion of a humeral
head. FIG. 7 shows the plate with the 4 compression screws removed
so the screw threads can be seen. Eight fastening screws 29 are
also shown extending through the holes 25 and 27 where they would
extend into the cortical bone of the intact humerus and affix the
plate 11 a thereto. In this bone plate system, known locking
arrangements in combination with the threads of the four holes 21
might be used that would prohibit back-out of the four compression
screws 23a. Alternatively, a modified cover plate might be used
having plugs that would appropriately abut the front surfaces of
socket head screws and prevent any back-out. Thus, by providing the
optional threads in the four holes 21, such a fixation plate is
adapted for use both in the improved bone plate system with the
recessed cover plate 39, as well as in a traditional arrangement
where the compression screws 23a are locked against any back-out
should a surgeon, for whatever reason, wish to employ such an
arrangement.
[0034] Although the invention has been described with regard to the
best mode presently known to the inventors, it should be understood
that various changes and modification as would be obvious to one
having ordinary skill in the art may be made without departing from
the scope of the invention, which is set forth in the claims
appended hereto. For example, although the bone plate system has
been described and illustrated with regard a proximal humeral head
fracture repair, it should be understood that it embodies
principles that might be advantageously incorporated in repair of
fractures of other load-bearing bones in vertebrates.
[0035] Particular features of the invention are emphasized in the
claims which follow.
* * * * *