U.S. patent number RE46,008 [Application Number 13/614,006] was granted by the patent office on 2016-05-24 for hindfoot nail.
This patent grant is currently assigned to Smith & Nephew, Inc.. The grantee listed for this patent is Sied W. Janna, Roy W. Sanders, William Stewart. Invention is credited to Sied W. Janna, Roy W. Sanders, William Stewart.
United States Patent |
RE46,008 |
Janna , et al. |
May 24, 2016 |
Hindfoot nail
Abstract
The present invention relates to a nail and fastener assembly
for use in providing a stable construct for optimal fixation of the
hindfoot and to methods for implanting the nail and fastener
assembly. One embodiment of the nail and fastener assembly provides
additional fixation, for example, in the form of one or more
threaded bores, to hold the fasteners in a fixed position. Another
embodiment provides angled bores to allow multi-planar and
multi-axial implantation of the fasteners. In some instances, the
fasteners may cross one or more articulating surfaces of the foot.
For example, the fastener may traverse one or more of the
calcaneo-cuboid and the talo-calcaneal articulating surfaces to aid
in more secure stabilization of the hindfoot.
Inventors: |
Janna; Sied W. (Memphis,
TN), Stewart; William (Austin, TX), Sanders; Roy W.
(Tampa, FL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Janna; Sied W.
Stewart; William
Sanders; Roy W. |
Memphis
Austin
Tampa |
TN
TX
FL |
US
US
US |
|
|
Assignee: |
Smith & Nephew, Inc.
(Memphis, TN)
|
Family
ID: |
36579552 |
Appl.
No.: |
13/614,006 |
Filed: |
September 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13483742 |
May 30, 2012 |
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12855377 |
Aug 12, 2010 |
RE44501 |
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Reissue of: |
11061699 |
Feb 18, 2005 |
7410488 |
Aug 12, 2008 |
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Reissue of: |
11061699 |
Feb 18, 2005 |
7410488 |
Aug 12, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
17/7233 (20130101); A61B 17/7291 (20130101); A61B
17/725 (20130101); A61B 17/72 (20130101) |
Current International
Class: |
A61B
17/56 (20060101); A61B 17/72 (20060101) |
Field of
Search: |
;606/62-68
;623/21.18 |
References Cited
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WO03/017822 |
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Mar 2003 |
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WO |
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|
Primary Examiner: Wehner; Cary E.
Attorney, Agent or Firm: Fish & Richardson P.C.
Parent Case Text
.Iadd.Notice: More than one reissue application has been filed for
the reissue of U.S. Pat. No. 7,410,488. The reissue applications
are the present application, which is a continuation reissue; U.S.
patent application Ser. No. 13/483,742, which is a divisional
reissue; and U.S. patent application Ser. No. 12/855,377, which is
a reissue of U.S. Pat. No. 7,410,488. .Iaddend.
Claims
What is claimed is:
.[.1. A method for at least partially fusing a patient's
calcaneo-cuboid articulating surface and talo-calcaneal
articulating surface in a hindfoot fusion process, the method
comprising: (a) providing a nail having a proximal portion and a
distal portion, the distal portion having a first angled
fastener-receiving hole and a second angled fastener-receiving
hole; (b) providing a first fastener adapted to be received in the
first angled fastener-receiving hole and a second fastener adapted
to be received in the second angled fastener-receiving hole; (c)
implanting the nail into a patient's tibial canal; (d) inserting
the first fastener through the first angled fastener-receiving hole
in the nail, such that the first fastener at least partially
crosses the patient's calcaneo-cuboid articulating surface; and (e)
inserting the second fastener through the second angled
fastener-receiving hole in the nail, such that the second fastener
at least partially crosses the talo-calcaneal articulating
surface..].
.[.2. The method of claim 1, wherein at least one of the first
fastener-receiving hole and the second fastener-receiving hole is
at least partially threaded..].
.[.3. A method of ankle arthrodesis on a patient, the patient
having a tibia, a cuboid, a talus, and a calcaneus, the tibia
having a tibial canal, the method comprising the steps of: a.
selecting a properly sized nail; b. reaming the tibial canal; c.
inserting the nail into the tibial canal; d. inserting a first
fastener into the calcaneus, through the nail, and into the cuboid;
and e. inserting a second fastener into the calcaneus, through the
nail, and into the talus, wherein a tip portion of the second
fastener achieves purchase within the talus..].
.[.4. The method of claim 3, further comprising the step of
removing cartilage from one or more bones..].
.[.5. The method of claim 3, further comprising the step of
incising a non-weight bearing part of a sole of the patient's
foot..].
.[.6. The method of claim 3, further comprising the step of
inserting a guide wire into the tibial canal..].
.[.7. The method of claim 3, further comprising the step of
inserting a transverse fastener into the calcaneus and the
nail..].
.Iadd.8. A method for fusing bones in a hindfoot fusion process,
comprising: providing a nail having a proximal portion and a distal
portion and a central longitudinal axis extending therebetween, the
distal portion defining at least two fastener-receiving holes, each
of the holes defining a through axis offset and non-perpendicular
to the nail axis, the through axes being non-parallel; providing at
least two fasteners; implanting the nail into a patient's tibial
canal; and inserting one of the fasteners through one of the holes
in the nail and inserting the other fastener through the other of
the holes in the nail with at least one of the two fasteners
engaging the calcaneus, wherein inserting one of the fasteners
comprises inserting the one of the fasteners into the cuboid.
.Iaddend.
.Iadd.9. The method of claim 8 wherein providing the nail comprises
the distal portion defining a third fastener-receiving hole between
the at least two fastener-receiving holes relative to the
longitudinal axis. .Iaddend.
.Iadd.10. The method of claim 9 further comprising providing a
third fastener and inserting the third fastener through the third
hole in the nail. .Iaddend.
.Iadd.11. A method for fusing bones in a hindfoot fusion process,
comprising: providing a nail having a proximal portion and a distal
portion and a central longitudinal axis extending therebetween, the
distal portion defining three fastener-receiving holes, at least
two of the holes defining through axes offset and non-perpendicular
to the nail central longitudinal axis, the third hole being
positioned between the at least two of the holes relative to the
longitudinal axis; providing three fasteners; implanting the nail
into a patient's tibial canal; and inserting the fasteners each
through one of the holes in the nail, wherein one of the fasteners
is inserted into the cuboid. .Iaddend.
.Iadd.12. The method of claim 11 wherein providing the nail
comprises the at least two of the holes through axes being
constrained to non-parallel planes. .Iaddend.
Description
FIELD OF THE INVENTION
The invention relates to nail and fastener assemblies that provide
stable fixation of the hindfoot.
BACKGROUND
Serious ankle problems can be caused by a number of conditions,
such as arthritis (e.g., osteoarthritis, rheumatoid arthritis),
diabetes, trauma, accidents, or severe deformation. One solution is
to replace the ankle joint with an implant or ankle prosthesis.
However, prostheses often fail due to subsidence, wear, and
loosening within a few years following implantation. There are also
anatomical considerations that make such implants non-feasible in
some cases. Poor results with prostheses have led many surgeons to
abandon implant arthroplasty in more serious cases and return to
ankle arthrodesis--fusing the joint to ultimately result in bone
fusion. Often, by the time fusion is selected as the best option,
there is minimal motion at the joint prior to surgery.
Ankle fusion typically involves using screws and pins to hold the
bone together. In a typical fusion surgery, the ankle joint is
fused, allowing the tibia (shinbone) to grow together or fuse with
the talus bone, the bone of the ankle that articulates with the
tibia and fibula, and the calcaneus, the bone that forms the ankle
joint. A long ankle arthrodesis "nail" may be inserted through the
heel and fixed into place with screws or pins. Often, one or more
screws or pins are inserted into the calcaneus, the bone at the
lower back part of the foot forming the heel, which provides more
stability.
Many of the currently available ankle fusion systems are less than
optimal. One reason is because the screws or pins used to fuse the
foot bones are secured only into the foot bones themselves; they
are not secured to the ankle arthrodesis nail through which they
are received. In some instances, an unsecured screw or pin can
dislodge itself from the patient's bone and migrate out over years
of use. Thus, there is a need in the art to provide a better
solution to reduce the risk of migration.
Another reason that many of the currently available fusion systems
are less than optimal is because they do not have angled
fastener-receiving holes that allow for multi-planar fixation.
Alternatively, if angled holes are present, they are not provided
at optimal angle ranges for securing and immobilizing the
ankle.
In some commercially available systems, the center of the
fastener-receiving hole opening(s) in the ankle arthrodesis nail is
perpendicular to the longitudinal axis of the nail, such that when
the fastener is inserted, it is also perpendicular to the nail.
This does not allow the surgeon to achieve purchase into preferred
bones of the foot, but instead, limits the surgeon to securing the
fastener into the calcaneus (the heel bone). Such systems also fail
to provide the option of inserting fasteners in multiple axes to
provide a more stable fixation system.
Moreover, fusion systems typically include one or more fasteners
that engage only one foot bone in use. The fasteners do not cross
articulating surfaces. It would be advantageous to provide a system
that allows one or more fasteners to cross one or more articulating
surfaces of the bones in the foot in order to provide more
stability.
Another disadvantage of some fusion systems is that they do not
provide nails with reinforced distal portions. If the nail is the
same diameter throughout its length, but there are fastener holes
in the distal portion, the implant may be weaker at that portion
due to increased stresses from the patient's weight. Thus, there is
a need for a fusion system that provides greater rigidity and
stability in use.
Accordingly, it would be advantageous to provide a nail and
fastener assembly that addresses many of the problems that have not
been solved by currently-available systems.
SUMMARY
The present invention comprehends various embodiments of nail and
fastener assemblies, which may be employed, among other things, for
use in providing a stable construct for optimal fixation of the
hindfoot. It also comprehends various methods for implanting the
nail and fastener assemblies.
Because bone quality is typically poor in patients who are
candidates for this procedure, it is beneficial for a system to
include a nail that provides additional fixation to hold the
fasteners, which may be screws, pins, partially threaded screws,
fasteners having a surface with threads or blades of various
pitches, shapes, and rotations about the fastener, helical blades,
bolts, or any other structure capable of holding and/or engaging
bone, in a fixed position. It is also beneficial for a system to
provide the option of stabilizing various articulating surfaces of
the foot.
Accordingly, certain embodiments of the present invention provide
fusion systems with fixation features between the nail and fastener
that secure the fastener into the nail. Other embodiments provide a
fusion system with one or more openings of the nail that receive
fasteners at various angles, allowing one or more fastener to cross
one or more articulating surfaces of the foot to provide for
multi-planar and multi-axial implantation of the fasteners. Certain
structures provide a fusion system with a fastener that crosses one
or more of the talo-calcaneal and the calcaneo-cuboid articulating
surfaces. Other embodiments combine these features or aspects of
them.
One structure according to certain embodiments of the invention
includes a hindfoot nail with a threaded fastener-receiving hole.
Other structures include angled fastener-receiving bores, and
further structures include assemblies adapted to fuse articulating
surfaces of a patient's foot. Methods of the invention provide
methods for at least partially fusing certain bones of the
patient's hindfoot.
Certain devices of the present invention accomplish these results
in a number of ways, some of which are discussed in detail below,
with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a dorsal view of the anatomy of the foot.
FIG. 2 shows a side view of a foot having an implanted nail
according to one embodiment of the invention.
FIG. 3 shows a perspective view of one embodiment of a nail and
fastener assembly.
FIG. 3A shows a perspective hind view of a foot having an implanted
nail and fastener assembly according to another embodiment of the
invention.
FIG. 4 shows a side view of a nail according to one embodiment of
the invention.
FIG. 4A shows a cross-sectional view of the nail of FIG. 4.
FIG. 5 shows another cross-sectional view of the nail of FIG.
4.
FIG. 6 shows a cross-sectional schematic view of the threaded
angled bores of the nail of FIG. 4 showing fasteners (in phantom)
inserted.
DETAILED DESCRIPTION OF THE DRAWINGS
Anatomy of the Foot and Ankle:
There are twenty-six bones in the human foot 10, shown in FIGS. 1
and 2. There are seven tarsal bones: the bone that forms the heel
is the calcaneus 12; the talus 14 connects to and supports the
tibia 30 (shown in FIG. 2) at the ankle. The five other tarsal
bones are the navicular 16, the cuboid 18, and three cuneiforms 20,
which form the middle of the foot. Next, five metatarsals 22 form
the lower portion of the instep of the foot. The metatarsals 22
radiate out to the phalanges 24, which are the toe bones.
Of the tarsal bones, the talus 14 and the calcaneus 12 are the
largest and are adjacent to each other. Also adjacent to the
calcaneus 12 is the cuboid 18. The calcaneus 12 and the talus 14
define an articulating surface 40 between the two bones (the
talo-calcaneal articulating surface), and the calcaneus 12 and the
cuboid 18 also define an articulating surface 42 (the
calcaneo-cuboid articulating surface). Some or all of these, or
combinations of them, are the foot bones and articulating surfaces
that can be of particular interest to certain embodiments of the
present invention.
Fusion System:
FIGS. 3 and 3A each show a fusion assembly 110 according to
embodiments of the invention. Assembly 110 features a nail 112 and
one or more fasteners 150. In FIG. 3, some fasteners 150 are shown
as partially threaded and partially smooth or fully threaded. In
FIG. 3A, all fasteners 150 are shown having threads 152. In short,
a surgeon may choose to use a combination of any type of
fasteners.
As shown in FIG. 2, nail 112 is adapted to be implanted into a
patient's tibial canal. The fasteners 150 are adapted to be
inserted through and received by the nail 112 and secure to
particular bones of the foot. Different nails 112 are typically
provided for the left and right sides of a patient's body to
account for differing angles.
As shown in FIG. 4, nail 112 has a distal portion 114 and a
proximal portion 116. As best seen in FIGS. 2 and 3A, part of the
proximal portion engages the tibia and part of the distal portion
engages the calcaneus. Nail 112, as is the case with other
components of embodiments disclosed herein, can be formed of
Titanium, Titanium alloys, Surgical Steel alloys, or other desired
material. Distal portion 114 is shown having a greater outer
diameter relative to the proximal portion 116 and may be
considered, if desired, also to include a frustoconical transition
segment between the portion with the greater outer diameter and the
smaller outer diameter. However, distal portion 114 need not
necessarily have a greater outer diameter than other portions of
the nail 112.
Nail 112 can be also cannulated, if desired. One form of such
cannulation is shown in FIGS. 4-5 and can be accomplished by
gundrilling or other appropriate techniques. Such cannulation
enhances the ability of the nail 112 to be inserted using a closed
surgical procedure, such as over a guide wire or rod. Cam elation
in the distal portion 114 or portions of it, can be of greater
diameter than cannulation in the proximal portion 116 or portions
of it, as desired.
At the distal portion 114 is a driving end 118 that has an
instrument-receiving portion 120. Instrument-receiving portion 120
may include any type of connecting portion, such as a threaded bore
119 (shown in FIG. 5) that is adapted to receive and fasten to
implantation instruments. Instrument-receiving portion 120 may also
have an optional keyway 121 (shown in FIG. 6) that can provide
additional stabilization with respect to implantation instruments.
Other options for connecting the instrument-receiving portion 120
to implantation instruments may be a ball and detent mechanism, a
dovetail and slot configuration, a lock and key configuration, or
any other stable locking mechanism.
Because distal portion 114 of nail 112 (which again may, if
desired, contain some or all of the frustoconical transition shown
in FIGS. 4-5) may include one or more angled fastener holes 122,
130, distal portion 114 may be provided with an outer diameter that
is larger than the diameter at proximal portion 116. In the
particular embodiment shown in FIGS. 4-5, the greater outer
diameter can in some ways be considered to provide favorable
properties such as any or all of increased resistance to bending,
rigidity, strength, stability, durability and enhanced reception
and/or retention of fasteners.
One aspect of embodiments of the present invention is that one or
more fasteners are received by and secured to a nail, as well as
being secured to the patient's bone. See, e.g., FIG. 3A. One
structure used to accomplish the securing of the fastener to the
nail can be a threaded bore and threaded fastener combination. In
this example, the nail can have a threaded bore 128 and the
fastener can have corresponding threads 152 at or near the portion
received by the nail.
In the specific embodiment shown in FIG. 3A, the fastener is a
threaded screw 150. Threads 152 may be provided in any number of
shapes (e.g., trapezoidal teeth, triangular teeth, square teeth),
pitches, and rotations (e.g., tightly wound around fastener or
"loosely" wound such that there is a greater distance between each
thread). The screw threads and the threads of the nail need not
have the same shape, pitch, or rotation, although they typically
will.
In an alternate embodiment (not shown), the fastener is a partially
threaded screw. Again, the threads may be provided in any number of
shapes, pitches, and rotations. In this example, the threads are
preferably located at or near the portion where the threads are
secured into nail to prevent their migration.
In a further embodiment, the fastener has a series of cutting edges
that engage a patient's bone. Cutting edges may be cutting blades,
helical blades, spikes, or any other structure capable of holding
and/or engaging bone. Cutting edges may cover all or just a portion
of fastener. Alternatively, fastener may feature a bolt, a moly
bolt, a tension spring, or any other structure capable of holding
and/or engaging bone.
In use, the threaded bore 128 is adapted to receive and secure a
corresponding structure on fastener with respect to nail 112, as
well as allow fastener to engage with bone. One or more openings in
the nail 112 may be provided as threaded bores. It is also possible
to provide a nail 112 having a combination of threaded and
non-threaded bores (the non-threaded bore structure is described
below). It is also possible to provide openings in the nail that
are partially threaded and partially non-threaded.
One optional feature that may be provided with assembly 110 is an
insert or bushing (not shown) to prevent rotation of the fastener.
See pending S&N application Ser. No. 10/999,572, filed Nov. 30,
2004 and titled "Humeral Nail," the entire contents of which are
hereby incorporated by this reference. This feature may provide a
function similar to fastener anchors that can be used to hang a
picture on a wall, i.e., the insert interferes with the rotation of
the fastener in the nail and can prevent it from wobbling or
threading out, without interfering with the ability of the fastener
to insert into the nail at a range of angles. The insert may be
used in connection with a threaded or non-threaded bore. It may be
secured with respect to nail by the threads, by a rib and locking
ring configuration, by injecting a biologic or bone cement through
the cannulation as each fastener is inserted, by an interference
fit, or any other securing means.
A further aspect of some embodiments of the present invention is
that fusion of the hindfoot can be established by connecting and
stabilizing certain articulating surfaces of the foot. In one
specific embodiment, the talus 14 and the calcaneus 12 are
connected to one another by a fastener that crosses the
talo-calcaneal articulating surface when implanted. In another
specific embodiment, the cuboid 18 and the calcaneus 12 are
connected to one another by a fastener that crosses the
calcaneo-cuboid articulating surface when implanted. This may be
done by specifically targeting these bones using an assembly 110
with angled holes or bores according to one embodiment of the
present invention, as shown in FIG. 3A. This particular embodiment
provides for multi-planar (and if desired, multi-axial) fixation.
The nail may also be adapted to be secured to the tibia 30 for
additional stability.
One particularly beneficial aspect of providing angled fastener
holes 122, 130 is that they are provided such that any fastener
received therein can target specific bones. In one structure
according to certain embodiments of the invention, the fasteners
are pin-like or substantially smooth. In another structure, the
fasteners may have a portion that is threaded (or that contains
cutting blades, helically shaped structures having any angle
relative to the fastener axis, or other fastening structure to
engage bone) that are adapted to secure to a patient's bone, and a
portion that is at least partially smooth. These fasteners may be
referred to as compression screws, an example of which is shown in
FIG. 3.
Compression screws have a portion adapted to attach to a patient's
bone, as well as an at least partially smooth portion that
articulates with the nail for sliding compression. The at least
partially smooth surface is allowed to "slide" within the nail,
such that when the patient applies pressure to the implant (for
example, if the implant is a weight-bearing implant in the foot,
the patient applies pressure when stepping down), the fastener
compresses the bones together. The bone fragments are allowed to
slide and bear on each other for better healing and fusion of the
site.
In certain embodiments, the portion that cooperates with a
patient's bone is adapted to cooperate with the calcaneus, and in
other embodiments, the portion that cooperates with a patient's
bone is adapted to cross one or more articulating surfaces of the
foot.
Alternatively, angled fastener holes may have internal threads 128.
In use, internal threads 128 of nail 112 cooperate with fastener
threads 152 of fasteners 150 to secure the fasteners into the nail
112, as well as into the patient's bone. For ease of reference,
fasteners will be referred to as fasteners 150 (which are shown as
threaded screws) throughout the remainder of this application,
although it is understood that fasteners may take any of the
above-described forms, such as compression screws, pins, partially
threaded screws, and so forth. See e.g. FIG. 3.
In embodiments in which the fastener is adapted to cross
articulating surfaces, fastener holes 122, 130 are provided at
optimal angles that allow the surgeon to achieve fastener
attachment into particular bones of the foot, such as the calcaneus
12, the talus 14, and the cuboid 18. Angled fastener holes 122, 130
are oriented so that fasteners 150 can be inserted into the nail
112 and cross one or more of the articulating surfaces 40 and 42 of
the foot bones.
For example, consider nail 112 having a central longitudinal axis
124 as shown in FIGS. 4-5. At least one angled fastener hole 122 is
positioned at an angle .theta. that is between about 45.degree. and
about 135.degree. off of the central longitudinal axis 124. (In
other words, when a fastener is inserted through the hole 122, the
fastener itself creates an axis 160 that forms an angle of between
about 45.degree. and about 135.degree. with the central
longitudinal axis 124, as shown in FIG. 4A.) In a particular
embodiment, at least one angled fastener hole 122 is positioned at
an angle between about 65.degree. and about 115.degree. off of the
central longitudinal axis 124. In an even more preferred
embodiment, the angled fastener hole 122 is positioned at an angle
between about 80.degree. and about 90.degree. off of the central
longitudinal axis 124, and most preferably, at about 85.degree. off
of the central longitudinal axis 124.
Central longitudinal axis 124 also intersects a plurality of
planes. One cross-section defined by central longitudinal axis 124
is central plane 125, which is the plane in the page of the paper.
This cross-sectional view is shown in FIG. 4A. In addition to its
angled orientation with respect to central longitudinal axis 124,
angled fastener hole 122 may also be disposed at an angle that is
rotated off of the plane 125 of the paper. (In other words, when a
fastener is inserted through hole 122, the fastener forms a second
plane that is not aligned with plane 125 and would either extend
from or retreat into plane 125 of the paper.) In one embodiment,
fastener 150 may either be rotated about 0-45.degree. into the
plane 125 of the page or rotated about 0-45.degree. out of the
plane 125 of the page. In one embodiment, angled fastener hole 122
is rotated about 2-30.degree. off of plane 125. In a further
embodiment, it is rotated about 5-15.degree. off of plane 125, and
is most preferably, about 10.degree. off of plane 125. (This angle
may be in either the medial or the lateral direction.)
In certain embodiments, angled fastener hole 122 is adapted to
receive a fastener that targets the cuboid 18 in use, or that at
least partially traverses the calcaneo-cuboid articulating surface
42, as shown in FIG. 3.
A second angled fastener hole 130 may also positioned on the distal
portion 114 of nail 112. This angled fastener hole 130 may be
positioned at an angle .alpha. that is between about 25.degree. and
about 135.degree. off of the central longitudinal axis 124, such
that a fastener inserted therein forms axis 162. In a particular
embodiment, second angled fastener hole 130 is positioned at an
angle between about 45.degree. and about 115.degree. off of the
central longitudinal axis 124. In an even more prefeffed
embodiment, second angled fastener hole 130 is positioned at an
angle between about 50.degree. and about 75.degree. off of the
central longitudinal axis 124, and most preferably, second angled
fastener hole 130 is positioned at about 55.degree. off of the
central longitudinal axis 124.
In addition to its angled orientation with respect to central
longitudinal axis 124, second angled fastener hole 130 may also be
rotated at an angle off of plane 125. For example, angled fastener
hole 130 may be rotated about 0-45.degree. off of plane 125, as
shown in FIG. 6, In one embodiment, angled fastener hole 130 is
rotated about 2-30.degree. off of plane 125. In a further
embodiment, it is rotated about 5-15.degree. off of plane 125, and
is most preferably, about 10.degree. off of plane 125. (Again, this
angle may also be in either the medial or the lateral direction. It
is preferred, although not required, that angled fastener hole 122
be about 10.degree. in the opposite direction of angled fastener
hole 130.)
In certain embodiments, second angled fastener hole 130 is adapted
to receive a fastener that targets the talus 14 in use, or that at
least partially traverses the talo-calcaneal articulating surface
40, as shown in FIG. 3.
There may be provided a third fastener hole 132, which also has
internal threads 128, but that may or may not be provided at an
angle. Consider nail 112 with a horizontal axis 127 that is
perpendicular to the central longitudinal axis 124 and that defines
a horizontal plane perpendicular to plane 125 (i.e., extending out
from the page). FIG. 5 shows the nail of FIG. 4 cut through a plane
that extends perpendicular to plane 125 and then rotated 90.degree.
to illustrate the threaded bore of fastener hole 132.
In one embodiment, fastener hole 132 is disposed through distal
portion 114 of nail 112 in the horizontal plane, give or take a few
degrees. When fastener 150 is inserted through fastener hole 132,
the fastener creates an axis that forms an angle of between about
80.degree.-100.degree., and preferably about 90.degree. with the
central longitudinal axis 124, as shown in FIG. 3. In certain
embodiments, the third fastener hole 132 is a transverse fastener
that targets the calcaneus 12.
In use, a surgeon may choose to use one or more of threaded holes
122, 130, 132, or any combination thereof. For example, a surgeon
may only need to use hole 122. In other cases, for example, if more
stability is needed, the surgeon will also use 130 and/or hole 132.
Alternatively, a surgeon may only use hole 132, but again, may use
additional holes for additional stability.
Fasteners 150 may be provided in any number of lengths, although it
is preferable that at least one fastener be provided in a length
that allows it cross one of more of articulating surfaces 40 and
42. Exemplary fastener lengths may be between 50 to 110 mm.
There may also be one or more static locking holes 136 or a dynamic
compression slots 137 at the proximal portion 116 of nail 112.
These openings 136, 137 are provided for rotational stability of
assembly 110 and are typically not threaded or angled, although
they can be angled and/or threaded as desired. Although the present
inventors believe that it would not be good surgical practice to
fix the fasteners to the holes in the proximal portion of nail 112
by threads because the nail 112 should not be overconstrained, it
is understood that there could be instances when such fixation
would be desired, and threaded upper holes are considered within
the scope of this invention.
The surgeon may choose between static or dynamic locking by placing
a fastener, pin, or small nail through either a static hole 136 or
dynamic slot 137 and into the tibia 30. It is preferred that one of
each opening 136, 137 be provided in order to give the surgeon the
most flexibility, although this is not required.
Method:
A surgeon first chooses the properly-sized nail 112. (Nails are
typically provided in 10-50 cm lengths.) The choice is based on the
length of the ankle from the bottom of the calcaneus to a suitable
fixation point on the tibia. In essence, the goal is to fuse the
nail 112 with the calcaneus 12 and the tibia 30 to immobilize the
ankle joint. Typically, the surgeon will remove cartilage from the
ankle to encourage the bones to fuse.
Although the surgery may be performed as a closed procedure (i.e.,
minimally invasive) and it is often preferable for it to be that
way due to ease of healing, some surgeons may also wish to remove
cartilage from between the bones prior to the procedure, which is
often performed using open surgical techniques. In short,
embodiments of the invention lend themselves to use during ether
type of procedure.
In one embodiment of the procedure, the surgeon makes an incision
into the non-weight bearing part of the sole of the foot (i.e., the
fatty tissue part of the heel) in line with the tibial planar axis.
The surgeon may insert a guide wire into the tibial canal to assist
reaming and the placement of nail 112. Once the canal has been
reamed to an appropriate diameter and depth, the nail 112 is driven
into the center (marrow) portion of the tibia 30, typically using
one or more of the instrument-receiving portion 120 or the keyway
121 for securing the implant instrumentation. Preferably, the
surgeon uses a C-arm or other image intensifier to insert the nail
112 over a guide wire or rod in a closed surgical procedure as well
as to insert the related fasteners.
Instrumentation may also be used to hold and guide drill bits to
prepare other bones for receiving fasteners. Similar
instrumentation may be used to hold and place a fastener. The
fastener can be rotated into place, hammered, or otherwise inserted
as desired. In some instances, guide wires may be used to place the
fastener as well.
If the surgeon plans to aid the fusion process by inserting a
fastener that will cross the calcaneo-cuboid articulating surface
42, the surgeon will insert the fastener through the posterior
aspect of the calcaneus, through the opening in the nail, and into
the cuboid to target that junction. In the embodiment shown, the
surgeon would place fastener 150 into the most inferior angled
fastener hole 122. The threads of fastener 150 cooperate with
internal threads 128, as well as achieve purchase into the
calcaneus 12 and cuboid 18. Alternatively, a compression screw, a
pin, an at least partially threaded screw, or other embodiments may
be used. In any event, this fastener will typically have a
relatively "shallow" angle, being inserted at the calcaneus and at
least partially crossing the calcaneo-cuboid articulating surface
42.
Once the first fastener is inserted, the surgeon may gently tap the
driving end 118 of the nail 112 to achieve compression of the
ankle. If the surgeon plans to place a transverse fastener (in this
case, a fastener that will cooperate with the calcaneus 12), the
fastener may be inserted through third fastener hole 132 in either
the medial to lateral or lateral to medial direction. Even though
this fastener is not necessarily strictly horizontal, it tends to
be the most horizontally-located of the fasteners.
Next, if the surgeon plans to aid the fusion process by inserting a
fastener that will cross the talo-calcaneal articulating surface
40, the surgeon will insert a fastener into the posterior of the
calcaneus, through an opening of the nail, and into the talus to
target that junction. In the embodiment shown, the surgeon would
place fastener 150 into the superior angled fastener hole 130. The
threads of fastener 150 will cooperate with internal threads 128,
as well as achieve purchase into the calcaneus 12 and talus 14.
Alternatively, a compression screw, a pin, an at least partially
threaded screw, or other embodiments may be used. In any event,
this fastener tends to be the most steeply angled of the three
(assuming that all three fasteners are used). Assuming the
patient's foot is standing on a horizontal surface, this fastener
will have a relatively steep "upward" angle to at least partially
cross the talo-calcaneal articulating surface 40.
This procedure has been described as if the surgeon is using three
fasteners, although it should be understood that a surgeon may
choose to use fewer or more fasteners and that nails according to
structures of this invention may also have fewer or more
fastener-receiving bores.
After the nail and junction fasteners have been properly placed in
the patient's foot, the surgeon will secure the nail 112 with a
fastener at the proximal portion 116 of the nail 112. The surgeon
may choose between static or dynamic locking by placing the
fastener through either a static hole 136 or a dynamic slot 137 in
nail 112.
Changes and modifications, additions and deletions may be made to
the structures and methods recited above and shown in the drawings
without departing from the scope or spirit of the invention and the
following claims.
* * * * *
References