U.S. patent application number 11/088680 was filed with the patent office on 2005-10-27 for bone fracture fixation systems with both multidirectional and unidirectional fixation devices.
Invention is credited to Orbay, Jorge L..
Application Number | 20050240186 11/088680 |
Document ID | / |
Family ID | 37012062 |
Filed Date | 2005-10-27 |
United States Patent
Application |
20050240186 |
Kind Code |
A1 |
Orbay, Jorge L. |
October 27, 2005 |
Bone fracture fixation systems with both multidirectional and
unidirectional fixation devices
Abstract
A fixation system includes a device having a plurality of like
threaded peg holes. Two types of pegs are couplable within the peg
holes. One type is multidirectional, and the shaft can be oriented
at various angles relative to an axis extending through the peg
hole. Another peg is directionally-fixed and limited to extension
through the peg hole in a single direction; i.e., coaxial with the
peg hole axis. The peg holes and both types of pegs are adapted
such that either of the pegs can be received within any of the peg
holes of the device.
Inventors: |
Orbay, Jorge L.; (Miami,
FL) |
Correspondence
Address: |
GORDON & JACOBSON, P.C.
60 LONG RIDGE ROAD
SUITE 407
STAMFORD
CT
06902
US
|
Family ID: |
37012062 |
Appl. No.: |
11/088680 |
Filed: |
March 24, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11088680 |
Mar 24, 2005 |
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10307796 |
Dec 2, 2002 |
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6893444 |
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10307796 |
Dec 2, 2002 |
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10159611 |
May 30, 2002 |
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6730090 |
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10307796 |
Dec 2, 2002 |
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10159612 |
May 30, 2002 |
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6767351 |
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10159612 |
May 30, 2002 |
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09735228 |
Dec 12, 2000 |
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6440135 |
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09735228 |
Dec 12, 2000 |
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09524058 |
Mar 13, 2000 |
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6364882 |
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09735228 |
Dec 12, 2000 |
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09495854 |
Feb 1, 2000 |
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6358250 |
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Current U.S.
Class: |
606/915 ;
606/281; 606/287; 606/291; 606/295 |
Current CPC
Class: |
A61B 17/7233 20130101;
A61B 17/8061 20130101; A61B 17/8605 20130101; A61B 17/72 20130101;
A61B 17/68 20130101; A61B 17/8047 20130101; A61B 17/8052 20130101;
Y10S 606/902 20130101; A61B 17/1728 20130101; A61B 17/8042
20130101; A61B 17/84 20130101 |
Class at
Publication: |
606/069 |
International
Class: |
A61B 017/58 |
Claims
1-9. (canceled)
10. A fracture fixation system, comprising: a) a fracture fixation
device defining at least one hole, said hole having an upper
portion provided with an internal thread, and a lower portion
having a substantially spherically concave surface; b) a first
fixation element having a head and a shaft, said head including a
first portion having an external thread adapted to thread with said
internal thread, a second portion having a substantially
spherically convex surface corresponding to said substantially
spherically concave surface, and an engagement portion for a
rotational driver; c) a second fixation element having a head and a
shaft, said head including a first portion defining a cup and
having a substantially spherically convex surface corresponding to
said substantially spherically concave surface; and d) a cap having
an external thread adapted to thread with said internal thread, an
engagement portion for a rotational driver, and a lower portion
sized to be received within said cup of said second fixation
element.
11. A fracture fixation system according to claim 10, wherein: at
least one of said substantially spherically concave surface of said
device, said substantially spherically convex surface of said first
fixation element and said substantially spherically convex surface
of said second fixation element is provided with a relatively high
coefficient of friction.
12. A fracture fixation system according to claim 10, wherein: one
of said shaft of said first fixation element and said shaft of said
second fixation element is non-threaded.
13. A fracture fixation system according to claim 10, wherein: said
fixation device is a plate device.
14. A fracture fixation system according to claim 13, wherein: said
plate device is a volar plate.
15. A fracture fixation system according to claim 10, wherein: said
fixation device is a nail-plate device.
16. A fracture fixation system according to claim 10, wherein: said
fixation device includes a plurality of threaded holes.
17. A fracture fixation system according to claim 10, wherein: said
cup of said second fixation element includes a surface area, and
said lower portion of said cap includes a protuberance adapted to
define a substantially small contact area relative to said surface
area of said cup.
18. A fracture fixation system according to claim 10, wherein: said
a cap comprises a base and a set screw, said base includes said
external thread adapted to thread with said internal thread of said
at least one hole, an internal thread, and said engagement portion
for a rotational driver, and said set screw includes an external
thread adapted to thread with said internal thread of said base, a
second engagement portion for a rotational driver, and said lower
portion of said cap.
19. A fracture fixation system according to claim 18, wherein: said
external thread of said base has a first pitch, said external
thread of said set screw has a second pitch, and said first pitch
is greater than said second pitch.
20. A fracture fixation system according to claim 10, wherein: said
cup of said second fixation element defines an engagement portion
for a rotational driver.
21. A fracture fixation system according to claim 10, wherein: said
at least one hole includes first and second holes, said first hole
defines a first axis and said second hole defines a second axis,
wherein said first fixation element is coupled within said first
hole in alignment with said first axis, and said second fixation
element is coupled within said second hole at an angle relative to
said second axis.
22. A fracture fixation system according to claim 21, wherein: said
first and second axes are parallel.
23. A fracture fixation system according to claim 21, wherein: said
angle is within a range of +15' relative to said second axis.
24. A kit for a fracture fixation system, comprising: a) a fracture
fixation device defining at least first and second like holes, each
said hole having an upper portion provided with an internal thread;
b) a first fixation element couplable within at least said first
hole, said first fixation element having a head and a shaft, said
head having an external thread engageable with said internal thread
and an engagement portion for a rotational driver; c) a second
fixation element couplable within at least said second hole, said
second fixation element having a head and a shaft; and d) a cap
having an external thread that is engageable with said internal
thread of said second hole and an engagement portion for a
rotational driver.
25. A kit according to claim 24, wherein: said cap includes a lower
portion that engages with said head of said second fixation element
to angularly fix said head of said second fixation element within
said second hole.
26. A kit according to claim 25, wherein: said lower portion of
said cap clamps against said head of said second fixation element
to provide said angular fixation.
27. A kit according to claim 25, wherein: said head of said second
fixation element includes a cup having a surface area, and said
lower portion of said cap includes a protuberance adapted to define
a substantially small contact area relative to said surface area of
said cup.
28. A kit according to claim 25, wherein: said cap comprises a base
and a set screw, said base includes said external thread adapted to
thread with said internal thread of said first and second holes, an
internal thread, and said engagement portion for a rotational
driver, and said set screw includes an external thread adapted to
thread with said internal thread of said base, a second engagement
portion for a rotational driver, and said lower portion of said
cap.
29. A kit according to claim 28, wherein: said external thread of
said base has a first pitch, said external thread of said set screw
has a second pitch, and said first pitch is greater than said
second pitch.
30. A kit according to claim 24, wherein: said head of said second
fixation element defines a cup having an engagement portion for a
rotational driver.
31. A kit according to claim 25, wherein: said head of said second
fixation element defines a concave surface, and said lower portion
of said cap has a spherically-curved convex surface corresponding
to said concave surface.
32. A kit according to claim 24, wherein: said first hole includes
a lower portion having a substantially spherically concave surface,
said first fixation element includes a portion having a
substantially spherically convex surface corresponding to said
spherically concave surface, said substantially spherically concave
surface and said substantially spherically convex portion intended
for contact with each other.
33. A kit according to claim 24, wherein: said shaft of said first
peg is non-threaded.
34. A kit according to claim 24, wherein: said shaft of said second
peg is non-threaded.
35. A kit according to claim 34, wherein: said second fixation
element includes an engagement portion for a rotational driver.
36. A kit according to claim 24, wherein: said fixation device is a
plate.
37. A kit according to claim 24, wherein: said fixation device is
nail-plate.
38. A kit according to claim 24, wherein: when said first and
second fixation element are fixed within said at least first and
second holes, said first and second fixation elements define a
plurality of non-parallel axes collectively oriented to provide a
framework for supporting fractured bone fragments.
39. A kit according to claim 24, wherein: said at least first and
second holes includes at least three holes closely spaced in a
linear or curvilinear arrangement.
40. A kit according to claim 24, wherein: said fixation device
includes a plate portion defining said at least first and second
holes.
41. A kit according to claim 40, wherein: said plate portion has a
body portion and a head portion angled relative said body portion,
said head portion defining said at least first and second
holes.
42. A kit according to claim 40, wherein: said fixation device also
includes a nail portion extending from said plate portion.
43. A kit according to claim 24, wherein: said fixation device
includes at least one non-threaded screw hole.
46. A method of treating a bone fracture, comprising: a) providing
a fixation device having a plurality of like threaded holes, each
of said holes defining an axis, said holes having an upper portion
provided with an internal thread and a lower portion having a
substantially spherically concave surface; b) positioning the
fixation device over the bone fracture; c) drilling holes through
the holes into the bone, wherein a first of the drilled holes is
drilled substantially coaxial with the axis through a peg hole, and
a second of the drilled holes is drilled at an angle relative to
the axis through a peg hole; d) providing a first fixation element
having a head and a shaft, said head including an external thread
adapted to thread with said internal thread, a portion having a
substantially spherically convex surface corresponding to said
substantially spherically concave surface, and an engagement
portion for a rotational driver; e) inserting said first fixation
element through one of the holes such that the shaft of the first
fixation element extends into the first drilled hole; f) providing
a second fixation element and a discrete cap, said second fixation
element having a head and a shaft, said head of said second
fixation element including a portion defining a cup and having a
substantially spherically convex surface corresponding to said
substantially spherically concave surface, and said cap having an
external thread, an engagement portion for a rotational driver, and
lower portion sized to be received within said cup of said second
peg; g) inserting the second fixation element through another of
the holes such that the shaft of the second fixation element
extends through the second drilled hole; and h) threadably engaging
the cap in the other of the holes until a portion of the cap
engages the head of the second fixation element.
47. A method according to claim 46, wherein: said threadably
engaging the cap causes clamping of the head of the second fixation
element between the cap and the fixation device.
48. A method according to claim 46, wherein: said providing said
second fixation element and a discrete cap includes providing said
second fixation element with a non-threaded shaft.
Description
[0001] This application is a continuation of U.S. Ser. No.
10/307,796, filed Dec. 2, 2002, which is a continuation-in-part of
both U.S. Ser. No. 10/159,611, filed May 30, 2002 now issued as
U.S. Pat. No. 6,730,090, and U.S. Ser. No. 10/159,612, filed May
30, 2002, now issued as U.S. Pat. No. 6,767,351, which are each
continuations-in-part of U.S. Ser. No. 09/735,228, filed Dec. 12,
2000, now issued as U.S. Pat. No. 6,440,135, which is a
continuation-in-part of both U.S. Ser. No. 09/524,058, filed Mar.
13, 2000, now issued as U.S. Pat. No. 6,364,882 and U.S. Serial No.
09/495,854, filed Feb. 1, 2000, now issued as U.S. Pat. No.
6,358,250, all of which are hereby incorporated by reference herein
in their entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates broadly to surgical devices. More
particularly, this invention relates to a bone fixation system
having support pegs.
[0004] 2. State of the Art
[0005] Fracture to the metaphyseal portion of a long bone can be
difficult to treat. Improper treatment can result in deformity and
long-term discomfort.
[0006] By way of example, a Colles' fracture is a fracture
resulting from compressive forces being placed on the distal
radius, and which causes backward displacement of the distal
fragment and radial deviation of the hand at the wrist. Often, a
Colles' fracture will result in multiple bone fragments which are
movable and out of alignment relative to each other. If not
properly treated, such fractures result in permanent wrist
deformity. It is therefore important to align the fracture and
fixate the bones relative to each other so that proper healing may
occur.
[0007] Alignment and fixation of a metaphyseal fracture are
typically performed by one of several methods: casting, external
fixation, interosseous wiring, and plating. Casting is
non-invasive, but may not be able to maintain alignment of the
fracture where many bone fragments exist. Therefore, as an
alternative, external fixators may be used. External fixators
utilize a method known as ligamentotaxis, which provides
distraction forces across the joint and permits the fracture to be
aligned based upon the tension placed on the surrounding ligaments.
However, while external fixators can maintain the position of the
wrist bones, it may nevertheless be difficult in certain fractures
to first provide the bones in proper alignment. In addition,
external fixators are often not suitable for fractures resulting in
multiple bone fragments. Interosseous wiring is an invasive
procedure whereby screws are positioned into the various fragments
and the screws are then wired together as bracing. This is a
difficult and time-consuming procedure. Moreover, unless the
bracing is quite complex, the fracture may not be properly
stabilized. Plating utilizes a stabilizing metal plate typically
against the dorsal side of the bones, and a set of parallel pins
extending from the plate into holes drilled in the bone fragments
to provide stabilized fixation of the fragments. However, the
currently available plate systems fail to provide desirable
alignment and stabilization. Similar problems regarding fracture
stabilization are present in non-metaphyseal fractures, as
well.
SUMMARY OF THE INVENTION
[0008] It is therefore an object of the invention to provide an
improved fixation and stabilization system for bone fractures.
[0009] It is another object of the invention to provide an improved
fixation and stabilization system for metaphyseal bone
fractures.
[0010] It is also an object of the invention to provide a fixation
and stabilization system that desirably aligns and stabilizes
multiple bone fragments in a fracture to permit proper healing.
[0011] It is a further object of the invention to provide a
fixation and stabilization system that is highly adjustable to
provide a customizable framework for bone fragment
stabilization.
[0012] It is an additional object of the invention to provide a
fixation and stabilization system that is relatively easy to
implant.
[0013] In accord with these objects, which will be discussed in
detail below, a fracture fixation and stabilization system is
provided which generally includes a device intended to be
positioned against a non-fragmented portion of a fractured bone,
one or more bone screws for securing the device along the
non-fragmented portion of the bone, and a plurality of bone pegs
coupled to the device and extending therefrom into bone fragments
adjacent the non-fragmented portion.
[0014] According to the invention, the device includes a plurality
of threaded peg holes adapted to receive the pegs therethrough. The
peg holes include an upper internally threaded portion, and a lower
spherically concave surface. In accord with the invention, two
types of pegs are provided for insertion through the threaded peg
holes, and the peg holes and the pegs are adapted such that either
type of peg can be used in any one of the peg holes of the
device.
[0015] The first type of peg includes a head and a shaft, with the
head having an upper externally threaded portion adapted to engage
the threads of the peg hole, a lower spherically convex portion,
and a driver receiving means, such as a proximal hex socket. Pegs
of the first type can be threadably engaged within the peg holes of
the plate to extend in alignment with axes through respective peg
holes; i.e., the first type of pegs are unidirectional or
fixed-directional.
[0016] The second type of peg includes a head and shaft, with the
head defining an upper cup and an outer spherically convex portion.
The second type of peg is adapted to operate in conjunction with a
cap having an externally threaded portion adapted to engage within
the threaded portion of the peg hole, a driver receiving means, and
a lower preferably spherically curved ball portion (or nub) sized
to be at least partially received within the cup. A peg of the
second type can be inserted through any peg hole and oriented in
any angle within a permitted range of angles relative to the axis
of the peg hole. The cap is then inserted into the peg hole and
tightened to clamp the head of the peg between the cap and the
lower concave surface surrounding the peg hole. As such, the second
type of pegs can be independently fixed in a selectable
orientation; i.e., the pegs are multidirectional.
[0017] This system is adaptable to substantially any fixation
system that can use stabilization pegs. For example, volar plates;
nail-plate systems for the distal radius, ulna, femur, and tibia;
shoulder plates; humeral plates; etc., can all be provided as a
system adapted to use by unidirectional and multidirectional
pegs.
[0018] Additional objects and advantages of the invention will
become apparent to those skilled in the art upon reference to the
detailed description taken in conjunction with the provided
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a top view of a volar fixation system according to
a first embodiment of the system of the invention;
[0020] FIG. 2 is a section view of a head portion of the volar
fixation system according to the invention, showing a
unidirectional fixed-angle peg inserted in a peg hole therein;
[0021] FIG. 3 is a section view of a head portion of the volar
fixation system according to the invention, showing a
multidirectional peg inserted in a peg hole therein;
[0022] FIG. 3a is a top perspective view of a cap for the peg shown
in FIG. 3;
[0023] FIG. 3b is a bottom perspective view of a cap for the peg
shown in FIG. 3;
[0024] FIG. 4 is a view similar to FIG. 3, in which a
multidirectional peg is angled relative to the orientation of the
peg in FIG. 3;
[0025] FIG. 5 is a view similar to FIG. 4, illustrating an
alternate multidirectional peg for use in accord with the system of
the invention;
[0026] FIG. 6 is a perspective view of the multidirectional peg
shown in FIG. 5;
[0027] FIG. 7 is a broken longitudinal section view across line 7-7
in FIG. 6;
[0028] FIG. 8 is a bottom perspective view of a first alternate cap
for a multidirectional peg.
[0029] FIG. 9 is a view similar to FIG. 4 showing the cap of FIG. 8
in use;
[0030] FIG. 10 is a top view of a multidirectional peg provided
with engagement structure;
[0031] FIG. 11 is a top view of a multidirectional peg provided
with other engagement structure;
[0032] FIG. 12 is a view similar to FIG. 4 showing a second
alternate cap for a multidirectional peg;
[0033] FIG. 13 is a top perspective view of the cap of FIG. 12;
[0034] FIG. 14 is a perspective view of a nail-plate device
provided with both unidirectional and multidirectional pegs in
accord with the invention; and
[0035] FIG. 15 is a perspective view of a humeral plate provided
with both unidirectional and multidirectional pegs in accord with
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Turning now to FIG. 1, a fracture fixation system 100
according to the invention is shown. According to a first
embodiment of the system 100, the system is particularly adapted
for aligning and stabilizing multiple bone fragments in a Colles'
fracture. However, as discussed further below, the preferred
aspects of the invention are applicable to numerous other fractures
fixation systems adapted to align and stabilize other bone
fractures, and particularly fractures occurring at or adjacent the
metaphyseal portion of long bones.
[0037] According the first embodiment, the system 100 generally
includes a substantially rigid T-shaped plate 102, commonly called
a volar plate. Such a plate is intended to be positioned against
the volar side of a fractured radial bone. The T-shaped plate 102
defines a head portion 116, and an elongate body portion 118
preferably angled relative to the head portion. The angle between
the head portion 116 and the body portion 118 is preferably
approximately 23.degree. and bent at a radius of preferably
approximately 0.781 inch. The distal edge 121 of the head portion
116 is preferably angled proximally toward the medial side at an
angle, e.g. 5.degree., relative to a line that is perpendicular to
the body portion 118. The plate 102 has a thickness of preferably
approximately 0.1 inch, and is preferably made from a titanium
alloy, such as Ti-6A-4V.
[0038] The body portion 118 includes four preferably countersunk
screw holes 124, 126, 127, 128 for the extension of bone screws 104
therethrough. One of the screw holes, 128, is preferably generally
oval in shape permitting longitudinal movement relative to the
shaft of bone screw.
[0039] The head portion 116 includes four peg holes 130, preferably
closely spaced (e.g., within 0.25 inch of each other) and
preferably arranged along a line or a curve, for individually
receiving pegs, discussed in detail below, therethrough. Referring
to FIG. 2, the peg holes 130 include an upper internally threaded
portion 132, and a lower spherically concave surface 134. Each peg
hole defines its own axis A.sub.H, and axes through the plurality
of peg holes may extend parallel to or obliquely relative to each
other.
[0040] In accord with the invention, two types of pegs are provided
for insertion through the threaded peg holes, and both types of
pegs can be used in any of the peg holes 130.
[0041] Still referring to FIG. 2, the first type of peg 140
includes a head 142 and a shaft 144. The head 142 has an upper
externally threaded portion 146 adapted to engage the threads 132
of the holes 130, a lower spherically convex portion 148 adapted to
seat against the concave surface 134 of the peg holes, and a driver
receiving means, such as a proximal hex socket 150. The shaft 144
is preferably non-threaded, as the pegs when inserted through the
peg holes and coupled to the plate are adapted to provide a
supporting framework about which bone fragments of the fracture can
heal, but are not necessarily intended to provide a compressive
force to the fragments. Alternatively, the shaft 144 may be
threaded for an application in which positive engagement between
the peg and bone is desired. Peg 140, when threadably engaged
within any of the respective peg holes 130 of the plate 102, has an
axis A.sub.P that extends in alignment with the axis A.sub.H of the
respective peg hole.
[0042] Referring to FIG. 3, the second type of peg 160 includes a
head portion 162 and a shaft 164. The head portion 162 defines an
upper cup 166 (concave receiving surface) and an outer spherically
convex portion 168. The spherically convex portion 168 has a radius
of curvature that substantially corresponds with the radius of
curvature of surface 134 about each peg hole. Surface 134 about the
peg hole, and/or the convex portion 168 of the peg are preferably
roughened, e.g., by electrical, mechanical, or chemical abrasion,
or by the application of a coating or material having a high
coefficient of friction.
[0043] Referring to FIGS. 3, 3a, and 3b, peg 160 is adapted to
operate in conjunction with a cap 170 having an externally threaded
portion 172 adapted to engage within the threaded portion 132 of a
peg hole 130, a driver receiving means 174, and a lower preferably
spherically curved ball portion (or nub) 176 sized to be at least
partially received within the concave upper cup 166 of the peg
160.
[0044] Referring to FIG. 4, peg 160 can be inserted through any of
peg holes 130 and infinitely adjusted such that an axis A.sub.P of
the peg may be oriented at any angle .alpha. within a range of
angles (e.g., .+-.15.degree.) relative to axis A.sub.H defined by
the peg hole. The cap 170 is then inserted into the peg hole 130
and tightened to clamp the head portion 162 of the peg 160 between
the cap 170 and the lower spherically concave surface 134
surrounding the peg hole. As such, peg 160 can be independently
fixed in an orientation selectable by the surgeon; i.e., the peg is
multidirectional.
[0045] More particularly, and referring now to FIGS. 1 through 4,
in use, the plate 102 is brought against the bone and aligned with
the fracture such that the peg holes are situated substantially
over the bone fragment or fragments. A first screw hole is drilled
by the surgeon through hole 128 and into the radius bone. A first
bone screw 104 is then inserted through the hole 128 in the plate
102 and secured to the bone. Prior to fully tightening the first
bone screw 104 against the plate, the plate may be longitudinally
adjusted relative to the screw. Once the proper position is
established, the first screw can be tightened, and additional
screws 104 may be inserted through the other screw holes 124, 126,
127 in a like manner.
[0046] The fractured bones are adjusted under the plate 102 into
their desired positions for healing. The surgeon then drills holes
into the bone for the pegs. The drilled holes may either be axial
(i.e., parallel to the respective A.sub.H of the peg holes) or
angled relative to the axes of the respective peg holes. The holes
may be drilled in any direction within the permissible range of
angles relative to the axes A.sub.H through the peg holes in accord
with the treatment designed by the surgeon. Such holes may be
drilled freehand, or may be assisted by a drill guide (not shown)
that limits the relative angle of the drilled holes to be within
the acceptable range of angles.
[0047] After each hole is drilled through a respective peg hole and
into the bone, one of the first or second types of pegs 140, 160 is
inserted through the peg hole in the plate and into the drilled
hole. For a peg hole drilled axial with the axis AH of the peg
hole, either of pegs 140 or 160 may be used. If the peg is of type
140, the shaft 144 of the peg is inserted through the peg hole 130
and into the drilled hole, and the peg is simply rotated about its
axis to couple the head 142 of the peg to the plate 102. If the peg
is of type 160, the peg is inserted through the peg hole and into
the drilled hole, and the cap 170 is inserted over the head 162 of
the peg and into the peg hole and then tightened to clamp the peg
160 in axial position.
[0048] For each hole that is drilled into bone at an angle relative
to the direction of the axis A.sub.H, a peg of type 160 is inserted
through the peg hole 130 into the bone, and then retained with a
cap 170, as discussed above.
[0049] Each hole may be drilled at the same angle as the others or
at relatively different angles, depending upon the circumstances of
the fracture being treated and the surgeon's treatment plan. In
most cases, the preferred supporting framework for the pegs 140,
160 will indicate pegs that extend in a plurality of oblique
directions such that, even though the shafts of the pegs are
preferably non-threaded, the pegs once inserted in the holes
operate to lock the bone fragment or fragments relative to the
plate 102.
[0050] Turning now to FIGS. 5, 6 and 7, a first alternate
multidirectional peg 160a for use in the above described system is
shown. Peg 160a includes a head portion 162a defining a an upper
cup 166a including substantially spherically-curved concave
surfaces 165a, and a Philips slot 167a. The head portion 162a also
includes an outer spherically convex portion 168a. The peg 160a
also includes a shaft 164a, which may be threaded or non-threaded.
The peg 160a is utilized in conjunction with cap 170. In the first
alternate embodiment, the peg 160a may be inserted through a peg
hole in a fixation device and into a hole drilled in bone with the
aid of an instrument having a Philips driver. The Philips driver is
received in the Philips slot 167a, and rotational force is provided
to the peg. The rotational force facilitates insertion of the shaft
164a of the peg 160a into a drilled hole, even where the shaft is
non-threaded.
[0051] Referring now to FIGS. 8 and 9, a first alternate embodiment
of a cap 170b for a multidirectional peg is shown. The cap 170b
includes a point 178b (e.g., a conical, frustoconical, cylindrical,
or other shaped protuberance) extending from the spherically curved
ball portion (or nub) 176b at the center of rotation thereof. The
point 178b or the entirety of the cap 170b is preferably made from
a material harder than the material of the peg 160. The point 178b
is adapted to make a substantially point-to-surface contact 180
with the surface of the cup 166 of the peg when the cap is threaded
into the upper portion 132 of the peg hole 130 of the fixation
device having a peg received therein. As the area being contacted
is greatly reduced, the force at the point of contact is
substantially increased, thereby enhancing the stability of the
peg.
[0052] Referring to FIGS. 10 and 11, as an alternate to a smooth
cup surface, the cup 166b at the head 162b of the peg can
optionally be provided with structure to aid engagement of the cup
166b by the point 178b of the cap 170b so at to fix the peg in an
angular orientation. Such structure may include the formation of a
plurality of compartments defined, e.g., by a plurality of wells
167b (FIG. 10) or an orthogonal (or honeycomb) arrangement of walls
169b (FIG. 11). Then, when the cap is inserted into the peg hole,
the point 178b engages with the structure, e.g., enters into a well
or a location between walls on the surface, to positively fix the
peg in a particular angular orientation.
[0053] Turning now to FIGS. 12 and 13, a second alternate
embodiment of a cap 170c for a multidirectional peg 160 is shown.
The cap 170c comprises two parts: a base 182c and a set screw 184c.
The base 182c has a diameter and threads 186c such that it is
adapted to be threadably received into the threaded upper portion
132 of a peg hole 130. The base 182c also includes a bore (defined
at the location of set screw 184c) with internal threads 188c,
preferably of a smaller pitch (i.e., a relatively greater number of
threads per inch) than threads 186c. The upper side 190c of the
base 182c includes a recess 192c adapted to receive a driver for
rotational driving the base. The recess 192c can have a hexagonal
shape (as shown) or be provided in any other non-circular shape
than can be defined about the bore. The set screw 184c includes an
upper square recess 194c for receiving a rotational driver,
external threads 196c corresponding to internal threads 188c, and a
lower spherical nub 198c.
[0054] In use, after a multidirectional peg 160 is inserted through
a peg hole 130 of a fixation device, the base 182c is rotationally
inserted into the upper portion 132 of the peg hole 130. It is
noted that rotation of the base 182c is subject to little
resistance, as even fully seating the base will not cause any
portion of the base to contact the head of the peg. After the base
182c is fully seated, the set screw 184c is rotationally driven
into the threaded bore of the base. The set screw 184c is inserted
until the nub 198c contacts the cup 166 of the peg 160 and places
thereon a force sufficient to stabilize the peg. As the set screw
is rotated on relatively smaller threads, greater mechanical
advantage is provided and thus significant frictional force can be
effected between the set screw 184c and the cup 166.
[0055] The above described system allowing the use of common peg
holes to receive either a peg at a fixed direction or a
multidirectional peg is adaptable to substantially any fixation
system that uses pegs.
[0056] For example, turning now to FIG. 14, a nail-plate system 200
is shown. Nail-plates are suitable for fixation of fractures at the
ends of long bones (metaphyseal fractures), such as the radius, the
ulna, the femur, and the tibia, with the device and pegs provided
in a size suitable for the bone for which the device is to be used.
The nail-plate system 200 includes a device 202 having a proximal
nail portion 212 and a plate portion 214 that is preferably
horizontally and vertically offset relative to the nail portion,
e.g., by a curvilinear neck portion (or transition zone) 216. As
such, the nail portion 212 and the plate portion 214 are preferably
fixed in a parallel, but non-coaxial relationship.
[0057] The nail portion 212 is preferably substantially circular in
cross section and includes a resilient section 220, and a tapered
relatively rigid section 222 generally substantially larger in
diameter. The rigid section 222 of the nail portion 212 preferably
includes two cortical screw holes 224, 226 arranged along the
length of the rigid section 222 and adapted to receive cortical
screws.
[0058] The plate portion 214 is substantially rigid and has a low
and narrow profile. The plate portion 214 has a preferably slightly
concave bottom surface 232 and a preferably slightly convex upper
surface 233. The plate portion 214 preferably includes a screw hole
250 adjacent or in the neck portion 216 that is adapted to receive
a stabilization screw. The plate portion 214 also includes one or
more, and preferably three longitudinally displaced, threaded peg
holes 234, 236, 238, each of which includes an upper threaded
portion and a lower spherical concave portion, as discussed above
with respect to peg holes 130 (see FIG. 2). The axes of the peg
holes 234, 236, 238 may be parallel or oblique relative to each
other. Regardless, the exact orientation of pegs placed through the
peg holes may be adjusted (within a range of angles) by the use of
all multidirectional pegs, such as peg 160 (and the associated cap
170), or with a combination of fixed-direction and multidirectional
pegs 140, 160, in the manner described above with respect to the
volar plate system 100. The implantation of the nail-plate is
discussed in detail in previously incorporated, co-owned U.S. Ser.
No. 10/159,611, filed May 30, 2002.
[0059] Turning now to FIG. 15, a humeral plate system 300 is shown
for fixation of a humeral fracture. The humeral plate 300 is an
elongate plate having a body portion 302 with a plurality of screw
holes 304, and a head portion 306 with a plurality of peg holes
308, similar in design to peg holes 130 (FIG. 2). Pegs 140 (FIG. 2)
and pegs 160 (FIGS. 3 and 4) and 160a (FIG. 6) and a cap therefor
170 (FIGS. 3a and 3b), 170b (FIG. 8), or 170c (FIG. 13) can be used
in the peg holes in the manner described above.
[0060] There have been described and illustrated herein several
embodiments of fracture fixation systems having threaded peg holes
adapted to individually receive both unidirectional (fixed angle)
and multidirectional (or directable) pegs. In the directable peg
embodiment, the head of a peg is preferably clamped between a
portion of the fixation plate and a discrete cap, preferably with
the head of the peg and fixation plate thereabout being treated to
have, or having as material properties, high friction surfaces to
enhance the fixation of the peg. Alternatively, the cup of the peg
may have structure to adapted to receive and capture a portion of
the cap. In the unidirectional embodiment, the lower portion of the
head of the peg is shaped in accord with a peg hole structure
adapted for the directable peg. While particular embodiments of the
invention have been described, it is not intended that the
invention be limited thereto, as it is intended that the invention
be as broad in scope as the art will allow and that the
specification be read likewise. Thus, while exemplar devices have
been discussed, it is not intended that such discussion define a
limitation to the claims. Other bone fixation devices, for example
and not by way of limitation, such as spinal fixators, are also
within the intended scope. Also, while particular materials for the
elements of the system have been disclosed, it will be appreciated
that other materials may be used as well. In addition, fewer or
more peg holes and pegs may be used, preferably such that at least
two pegs angled relative to each other are provided. Also, while it
is disclosed that the pegs may be directed through a range of
15.degree., the peg holes and the heads of the pegs may be modified
to permit a greater, e.g. up to 30.degree., or smaller, e.g.
5.degree., range of such angular direction. Furthermore, while a
hex slot is disclosed on both the head of the fixed angle peg and
the cap for receiving a driver to applying rotational force to the
peg and cap, it will be appreciated that other rotational
engagement means, e.g., a square, a Phillips, slotted, star,
multi-pin, or other configuration may be used. Also, the device and
pegs may be provided in different sizes adapted for implant into
different size people. Furthermore, while some elements have been
described with respect to the mathematically defined shapes to
which they correspond (e.g., spherical), it is appreciated that
such elements need only correspond to such shapes within the
tolerances required to permit the elements to adequately function
together; i.e., the elements may be only "substantially" spherical
in curvature such that the elements can rotate relative to one
another and be securely clamped. Furthermore, where parts are
intended to rotate relative to each other, it is appreciated,
although less preferred, that the parts may together define
sufficient space therebetween permitting such rotation even if
surface-to-surface contact is not maintained along the facing
portions of the relevant parts. Moreover, various aspects of the
several embodiments can be combined in yet other embodiment. For
example, the set screw of a two-part cap can be provided with a
point on its ball portion adapted to engage the cup of a peg. It
will therefore be appreciated by those skilled in the art that yet
other modifications could be made to the provided invention without
deviating from its spirit and scope as claimed.
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