U.S. patent application number 12/990772 was filed with the patent office on 2011-02-24 for surgical technique and apparatus for proximal humeral fracture repair.
This patent application is currently assigned to TORNIER. Invention is credited to Loic Barouch, Pascal Boileau.
Application Number | 20110046625 12/990772 |
Document ID | / |
Family ID | 41217600 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110046625 |
Kind Code |
A1 |
Boileau; Pascal ; et
al. |
February 24, 2011 |
SURGICAL TECHNIQUE AND APPARATUS FOR PROXIMAL HUMERAL FRACTURE
REPAIR
Abstract
A method and apparatus of reattaching a bone fragment to a
proximal humerus of a humerus in a shoulder joint. The method
includes introducing a distal end of the humeral nail into a
medullary canal of the humerus. A first proximal screw is engaged
with the bone fragment and a first proximal bore in the proximal
end of the humeral nail to move the bone fragment toward the
proximal humerus. The humeral nail and the attached bone fragment
are rotated relative to the medullary canal of the humerus to
position the bone fragment to an anatomically optimal location. The
bone fragment is preferably one of a greater or lesser tuberosity
of the proximal humerus. The method and apparatus can be used to
reattach bone fragments in a variety of other joints.
Inventors: |
Boileau; Pascal; (Nice,
FR) ; Barouch; Loic; (Carisieu, FR) |
Correspondence
Address: |
FAEGRE & BENSON LLP;PATENT DOCKETING - INTELLECTUAL PROPERTY
2200 WELLS FARGO CENTER, 90 SOUTH SEVENTH STREET
MINNEAPOLIS
MN
55402-3901
US
|
Assignee: |
TORNIER
Saint Ismier
FR
|
Family ID: |
41217600 |
Appl. No.: |
12/990772 |
Filed: |
May 6, 2009 |
PCT Filed: |
May 6, 2009 |
PCT NO: |
PCT/IB09/53468 |
371 Date: |
November 2, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61051320 |
May 7, 2008 |
|
|
|
Current U.S.
Class: |
606/64 |
Current CPC
Class: |
A61B 17/7233 20130101;
A61B 17/72 20130101; A61B 17/7241 20130101 |
Class at
Publication: |
606/64 |
International
Class: |
A61B 17/56 20060101
A61B017/56 |
Claims
1. A method of reattaching a bone fragment separated from a
proximal humerus of a humerus in a shoulder joint, the method
comprising the steps of: introducing a distal end of the humeral
nail into a medullary canal of the humerus; engaging a first
proximal screw with the bone fragment and a first proximal bore in
the proximal end of the humeral nail to fix the attach the bone
fragment to the nail; and rotating the humeral nail and the
attached bone fragment relative to the medullary canal of the
humerus to position the bone fragment to an anatomically optimal
location.
2. The method of claim 1, further comprising the step of
rotationally orienting the humeral nail relative to the bone
fragment before engaging the first proximal screw.
3. The method of claim 1, further comprising the step of using an
aiming device to locate the first proximal screw relative to the
humeral nail.
4. The method of claim 1, further comprising the step of attaching
an aiming device to a proximal end of the humeral nail.
5. The method of claim 1, further comprising the step of advancing
the first proximal screw in the first proximal bore so that a
distal end of the first proximal screw does not substantially
extend past the humeral nail.
6. The method of claim 1, further comprising the step of engaging a
second proximal screw with the proximal humerus and a second
proximal bore in the proximal end of the humeral nail.
7. The method of claim 1, wherein the humeral nail and first
proximal screw are implanted percutaneously.
8. The method of claim 1, further comprising the step of engaging a
plurality of proximal screws with the proximal humerus and a
plurality of proximal bores in the proximal end of the humeral
nail.
9. The method of claim 1, further comprising the step of engaging
at least one distal screw with the humerus and a distal bore in the
distal end of the humeral nail.
10. The method of claim 1, wherein engaging the first proximal
screw comprises engaging the first proximal screw with a greater
tuberosity of the proximal humerus, into the proximal humerus, and
into the first proximal bore in the proximal end of the humeral
nail.
11. The method of claim 1, wherein engaging the first proximal
screw comprises engaging the first proximal screw with a lesser
tuberosity of the proximal humerus, into the proximal humerus, and
into the first proximal bore in the proximal end of the humeral
nail.
12. The method of claim 1, further comprising the step of engaging
another proximal screw with a proximal humeral and a proximal bore
in the proximal end of the humeral nail, the other proximal screw
being located about 30 degrees to about 40 degrees relative to a
neutral axis.
13. The method of claim 1, further comprising the step of engaging
another proximal screw with a proximal humeral and a proximal bore
in the proximal end of the humeral nail, the other proximal screw
being located about 90 degrees to about 100 degrees relative to a
neutral axis.
14. The method of claim 1, wherein the first proximal screw is
located about 50 degrees to about 60 degrees relative to a neutral
axis.
15. The method of claim 1, wherein rotating the humeral nail and
the attached bone fragment within the medullary canal of the
humerus comprises rotating the humeral nail and the attached bone
fragment about zero degrees to about 40 degrees before a second
proximal screw is engaged with the humeral nail.
16. The method of claim 1, wherein a humeral head of the proximal
humerus is retained medially by the glenoid, anteriorly and
posteriorly by the rotator cuff muscles and the tuberosities, and
superiorly by the humeral nail.
17. The method of claim 1, wherein a humeral head of the proximal
humerus is retained to the proximal humerus solely with anatomical
features of the shoulder joint.
18. The method of claim 1, wherein the humeral nail comprises a
substantially linear shaft.
19. The method of claim 1, wherein the angular offset and relative
position of the proximal screw facilitates insertion of the screw
at the insertion muscle location, where the screws are retained by
substantially solid bone and the muscle.
20. A humeral nail comprising: a substantially linear elongate
shaft having a proximal portion, a distal portion, and a central
axis and configured to define a neutral axis with respect to the
central axis; at least one distal bore at the distal portion of the
elongate shaft having a distal bore axis; a first proximal bore at
the proximal portion of the elongate shaft positioned between about
50 degrees and about 60 degrees relative to a neutral axis in a
postero-anterior direction; a second proximal bore at the proximal
portion of the elongate shaft positioned between about 30 degrees
and about 40 degrees relative to the neutral axis in a
postero-anterior direction; a third proximal bore at the proximal
portion of the elongate shaft positioned between about 90 degrees
and about 100 degrees relative to the neutral axis in an
antero-posterior direction; a first distal screw for engagement
with the first distal bore; a first proximal screw for engagement
with the first proximal bore; a second proximal screw for
engagement with the second proximal bore; and a third proximal
screw for engagement with the third proximal bore, wherein the
first proximal screw has a length shorter than a length of the
second and third proximal screws.
21. The humeral nail of claim 20, wherein both the second and third
proximal bores are positioned on one side of the first proximal
bore along the elongate shaft.
22. The humeral nail of claim 20, further comprising a fourth
proximal bore at the proximal portion of the elongate shaft
positioned between about 20 and about 40 degrees relative to the
neutral axis in an antero-posterior direction.
23. The humeral nail of claim 22, wherein both the second and third
proximal bores are positioned on one side of the first proximal
bore along the elongate shaft, whereas the fourth proximal bore is
positioned on the opposite side of the first proximal bore.
24. The humeral nail of claim 22, further comprising a fourth
proximal screw for engagement with the fourth proximal bore,
wherein the length of the first proximal screw is shorter than a
length of the fourth proximal screw.
25. The humeral nail of claim 20, wherein the distal bore axis of
the at least one distal bore is substantially parallel to the
neutral axis.
26. The humeral nail of claim 20, wherein the distal bore axis of
the at least one distal bore is at an angle of between about 15
degrees and about 25 degrees relative to the neutral axis in an
antero-posterior direction.
27. The humeral nail of claim 20, wherein at least two distal bores
are provided at the distal portion of the elongate shaft.
28. The humeral nail of claim 20, wherein at least one of the
first, second, third and fourth proximal screws includes a head
portion and a body portion, wherein the head portion has a diameter
that is about two times greater than a diameter of the body
portion, and further wherein the head portion has a substantially
flat surface that is connected to the body portion.
Description
[0001] This application claims priority to U.S. provisional patent
application 61/051,320, filed May 7, 2008 herein incorporated by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a method and apparatus for
fixation of proximal humeral fractures. In particular, the present
invention relates to a humeral nail for reduction and orientation
of the tuberosities at a humeral fracture site.
BACKGROUND OF THE INVENTION
[0003] As illustrated in FIG. 1, the humerus 100 of the upper arm
is part of a "ball and socket" joint at the shoulder 102. The
proximal humerus 102 includes a large rounded humeral head 106
joined to the humerus shaft 116 by a humeral neck 108 and two
eminences, the greater and lesser tuberosities 110, 112.
[0004] Proximal humeral fractures are the most common humeral
fractures. These are often found in patients who have fallen on
their arms, creating an axial load on the humerus 100 that causes a
fracture of the humeral head 106. In a two-part fracture, the
humeral head 106 or a single portion of the head is broken from the
humeral shaft 116. In more severe fractures, the humeral head 106
tends to fracture from one or both of the tuberosities 110, 112. As
illustrated in FIG. 1, upon occurrence of a fracture the muscles
104 attached to the tuberosities 110, 112 and the humeral shaft 116
pull the humeral head 106, tuberosities 110, 112, and humeral shaft
116 in the directions indicated and away from the correct
anatomical positions.
[0005] To repair a complex fracture such as illustrated in FIG. 1,
a separate reduction device is used to position and retain one or
more of the humeral head 106, tuberosities 110, 112, and humeral
shaft 116 in the correct anatomical position. As used herein,
"reduce" or "reduction" refers to positioning a bone fragment to an
anatomically optimal position.
[0006] The humeral head 106, tuberosities 110, 112, and humeral
shaft 116 are then secured using conventional techniques such as
external fixation, percutaneous pinning, plating, intramedullary
nailing, shoulder arthroplasty, and others. These methods, however,
are not entirely suitable for treatment of more complex fractures,
or when tissues are weakened by disease. In these cases, surgical
replacement of the shoulder joint is often required.
[0007] U.S. Pat. No. 5,472,444 (Huebner et al.) discloses use of a
humeral nail for fixation of proximal humeral fractures. Huebner
provides an elongated tapered nail or rod having an elongated body
with a curved tapered shank that may be secured within a proximal
portion of the humeral shaft, with a contiguous proximal portion of
the nail extending proximally from the shank to provide a solid
foundation to which the humeral head fragments may be secured. The
proximal portion has transverse holes oriented at selected angles
to receive fasteners attached to the fragments. Huebner does not,
however, provide a mechanism to reduce the fracture and retain the
fragments during fixation. Also, if a screw is not accurately
located in the fragment, Huebner does not provide a mechanism to
adjust the location of the fragment relative to the humeral
head.
SUMMARY OF THE INVENTION
[0008] The present invention relates to a system and method for
repairing a proximal humeral fracture using a humeral nail for both
reduction and retention of the fragments to the correct anatomical
position. The system and method provides for limited rotation of
the humeral nail within the medullary canal to adjust the position
of a bone fragment relative to the humeral head.
[0009] In the preferred embodiment, the procedure is performed
entirely percutaneously without the use of a reduction device.
Small incisions are made in the skin at selected locations, rather
than requiring the entire shoulder joint to be exposed. The humeral
nail can be inserted percutaneously, with minimal risk of damage to
the rotator cuff. The positioning of the proximal screws limits
interference with the articular surface of the humeral head. In the
preferred embodiment, no screws are required to retain the humeral
head in its anatomical position. Rather, the humeral head is
retained medially by the glenoid, anteriorly and posteriorly by the
rotator cuff muscles and the tuberosities and superiorly by rotator
cuff muscle.
[0010] An aiming device is required to position the screws to
engage with the corresponding bores in the humeral nail. In one
embodiment, the aiming device is attached to the humeral nail. The
aiming device is preferably constructed from a radiolucent material
to permit imaging when reconstructing the fracture and locating the
nail and the screws. In another embodiment, the aiming device
involves various imaging techniques. As used herein, "imaging"
refers x-ray, MRI, CAT-scan, ultrasound, fluoroscopy, and the like.
As used herein, "aiming device" refers to both mechanical devices
and imaging devices.
[0011] The humeral nail is positioned in the medullary canal in the
humerus. The humeral nail is preferably substantially straight
which permits it to rotate after insertion in the medullary canal
and helps avoid the need to insert the nail through the insertion
of the cuff. A first proximal screw is used to move one of the
greater or lesser tuberosities fragmented from the humerus toward
the humeral nail. The distal tip of the first proximal screw is
preferably not advanced substantially beyond the humeral nail.
Consequently, the fragment of the greater or lesser tuberosity
attached to the humeral nail and the humeral nail itself can be
rotated without damaging surrounding bony structures and soft
tissues. After the initial movement of the fragment of the greater
or lesser tuberosity by the first proximal screw, the attached
fragment of the greater or lesser tuberosity is reduced by rotation
with the humeral nail to an anatomically optimum position.
[0012] The present invention is also directed to a method of
reattaching a bone fragment separated from a proximal humerus in a
shoulder joint. The method includes introducing a distal end of the
humeral nail into a medullary canal of the humerus. A first
proximal screw is engaged with the bone fragment and a first
proximal bore in the proximal end of the humeral nail to attach the
bone fragment to the humeral nail. The humeral nail and the
attached bone fragment are rotated relative to the medullary canal
of the humerus to position the bone fragment to an anatomically
optimal location. The bone fragment is preferably one of the
tuberosities.
[0013] The humeral nail is optionally rotationally oriented
relative to the bone fragment before engaging the first proximal
screw. An aiming device is optionally used to locate the first
proximal screw relative to the humeral nail. In one embodiment, the
aiming device is attached to a proximal end of the humeral
nail.
[0014] The first proximal screw is preferably advanced in the first
proximal bore so that a distal end of the first proximal screw does
not substantially extend past the humeral nail. A second proximal
screw is engaged with the proximal humerus and a second proximal
bore in the proximal end of the humeral nail to prevent further
rotation of the humeral nail. The entire procedure is preferably
performed percutaneously. The humeral head is preferably retained
laterally and inferiorly by the tuberosities, medially by a glenoid
of the shoulder joint, and superiorly, anteriorly and posteriorly
by a rotator cuff tendon of the shoulder joint, without the use of
screws. That is, the humeral head is retained to the proximal
humerus solely with anatomical features of the shoulder joint.
[0015] The present invention is also directed to a method of
reattaching a bone fragment to the proximal humerus. The method
includes attaching an aiming device to a proximal end of a
substantially straight humeral nail. A distal end of the humeral
nail is introduced into a medullary canal of the humerus. An aiming
device is used to locate a first proximal screw through the bone
fragment, into the proximal humerus, and into a first proximal bore
in the proximal end of the humeral nail. The first proximal screw
is advanced into the first proximal bore to stabilize the bone
fragment relative to the humeral nail and, in some embodiments, to
bring the bone fragment into engagement with the proximal humerus.
The distal end of the first proximal screw preferably does not
substantially extend past the humeral nail. The humeral nail is
then rotated within the medullary canal of the humerus so that the
bone fragment is reduced to an anatomically optimal location. A
second proximal screw is engaged with the proximal humerus and a
second proximal bore in the proximal end of the humeral nail to
prevent further rotation of the humeral nail.
[0016] In one embodiment, the first proximal screw is shorter than
a conventional fixation screw so as to not extend substantially
beyond the humeral nail and interfere with rotation of the attached
fragment and the humeral nail. That is, the screw is of adequate
length to traverse the distance from the cortical wall to the
humeral nail. In another embodiment, the first proximal screw is
only partially advanced into the first proximal bore in the humeral
nail. Only after reduction of the fragment through rotation of the
humeral nail to an anatomically optimal location is the first
proximal screw advanced the remainder of its length.
[0017] An aiming device is then used to locate additional screws to
reduce and retain other fragments of the humeral head to the
humeral nail. The aiming device is also preferably used to locate
screws to distally-located bores in the humeral nail. In one
embodiment, at least one distal screw is delivered with the forearm
in a neutral rotation. The aiming device can be any of a variety of
structures that are fixed or rotatable relative to the humeral
nail.
[0018] One embodiment of the present invention is a humeral nail
including a substantially linear elongate shaft having a proximal
end and a distal end, a distal bore at the distal end of the
elongate shaft and a plurality of proximal bores at the proximal
end of the elongate shaft.
[0019] In some embodiments, a neutral axis is an intersection of a
horizontal plane with a frontal plane containing a central axis of
the humeral nail. As such, when the arm is in a neutral rotation
position, the neutral axis is substantially perpendicular to the
forearm. In some embodiments, an angulated location of the proximal
screw(s) is measured with respect to the neutral axis.
[0020] One proximal bore is optionally positioned at between about
30 degrees and about 40 degrees relative to the neutral axis, also
described as the neutral position. Another proximal bore is
positioned at between about 90 degrees and about 100 degrees
relative to the neutral position. Still another third proximal bore
is positioned at between about 50 degrees and about 60 degrees
relative to the neutral position.
[0021] Terminology such as "first," "second," "third," etc., is
used herein to designate particular components being described.
Because various components of the embodiments described herein can
be positioned in a number of different orientations and in a number
of different sequences, this terminology is used for the purposes
of illustration and is not intended to be read in a restrictive
manner.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0022] FIG. 1 is a perspective view of an exemplary proximal
humeral fracture.
[0023] FIG. 2A is a perspective view of a humeral nail in
accordance with an embodiment of the present invention.
[0024] FIG. 2B is a view similar of FIG. 2A, which shows the
humeral nail in accordance with another embodiment of the present
invention.
[0025] FIG. 3 is a top schematic view of the humeral nail implanted
in the humerus in accordance with an embodiment of the present
invention.
[0026] FIG. 4A is a schematic view of a proximal end of the humeral
nail in accordance with an embodiment of the present invention.
[0027] FIG. 4B is a top cross-sectional view through lines A-A of
FIG. 4A of the location of a second proximal bore of the humeral
nail in accordance with an embodiment of the present invention.
[0028] FIG. 4C is a top cross-sectional view through lines B-B of
FIG. 4A of the location of a third proximal bore of the humeral
nail in accordance with an embodiment of the present invention.
[0029] FIG. 4D is a top cross-sectional view through lines C-C of
FIG. 4A of the location of a first proximal bore of the humeral
nail in accordance with an embodiment of the present invention.
[0030] FIG. 4E is a top cross-sectional view through lines D-D of
FIG. 4A of the location of a fourth proximal bore of the humeral
nail in accordance with an embodiment of the present invention.
[0031] FIG. 5 is a top view showing the respective angular offsets
of a plurality of proximal screws in accordance with an embodiment
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] FIGS. 2A, 2B, 3, 4A-4E and 5 show a humeral nail 10. As
shown in FIG. 3, this humeral nail is intended to be implanted in
the humerus 100, shown in FIG. 1 already described, of a patient to
fixate a fracture F at or proximate the greater tuberosity 110 and
lesser tuberosity 112 of the proximal humerus. The humeral nail 10
includes a substantially linear shaft 12 having a proximal portion
14 and a distal portion 16. The humeral nail 10 is introduced
through the humeral head 106 of the humerus 100 and extends within
the humeral shaft 116 such that the distal end 16 of the humeral
nail 10 is positioned within the medullary canal of the humeral
shaft 116.
[0033] It will be noted that the shown humeral nail 10 is designed
to be implanted in the right humerus of a patient. A humeral nail
that is to be implanted in the left humerus of a patient will be a
mirror-image of the humeral nail depicted in the figures.
[0034] In the preferred embodiment, small incisions are made in the
skin at selected locations, rather than requiring the entire
shoulder joint to be exposed. Percutaneous procedures preferably
require incisions of less than about 3.81 centimeters, more
preferably less than about 2.54 centimeters, and most preferably
less than about 1.27 centimeters, although a variety of dimensions
are contemplated. The humeral nail 10 can be inserted
percutaneously, with minimal risk of damage to the rotator
cuff.
[0035] Although the humeral nail 10 is primarily discussed as being
implanted in a patient's arm to fixate a proximal humeral fracture,
the present method and apparatus applies equally well to fractures
in other locations of a patient's body without departing from the
intended scope of the present invention. For example, the humeral
nail 10 may be modified to repair proximal or distal femoral
fractures, proximal or distal radial fractures, etc.
[0036] In the preferred embodiment, the humeral nail 10 functions
similarly to a device for repairing massive rotator cuff tears and
is based on reattaching the greater and lesser tuberosities 110,
112 to fixate the fracture F, rather than stabilizing the humeral
head 106. The humeral nail 10 is based on the horizontal plane and
is thus able to fixate the fracture F without introducing a screw
through the articular surface 106A of the humeral head 106. This is
accomplished in part by reducing both the tuberosities 110, 112 and
providing a stable platform for the humeral head 106. Using this
methodology, the humeral nail 10 is designed to treat multi-part
fractures (e.g., 2-part, 3-part, 4-part, etc.) in the horizontal
plane using a simple and reproducible surgical technique. In
addition, the humeral nail 10 can be percutaneously introduced at a
location where the humeral head 106 intersects the tuberosities
110, 112, minimizing the invasiveness of the surgery. The fracture
F is fixated using particular height and angulation specifications
of the humeral nail 10.
[0037] FIGS. 2A and 2B show a perspective view of the humeral nail
10 in accordance with two embodiments of the present invention.
FIG. 3 shows a top schematic view of the humeral nail 10 implanted
in the humerus 100. FIGS. 2A, 2B and 3 will be discussed in
conjunction with one another.
[0038] The shaft 12 of the humeral nail 10 is substantially linear
and has a central axis CA extending through a length of the humeral
nail 10. The substantially linear shape of the shaft 12 allows the
humeral nail 10 to be rotated within the medullary canal without
damaging surrounding bone and soft tissue. The proximal portion 14
of the humeral nail 10 includes a first proximal bore 18A, a second
proximal bore 18B, a third proximal bore 18C and optionally, a
fourth proximal bore 18D. The proximal bores 18A-18D are spaced
from a proximal end 23 of the humeral nail 10 and each other at
particular heights and angles to permit fixation of the fracture F
at the humeral head 106. The third proximal bore 18C is positioned
below the second proximal bore 18B, the first proximal bore 18A is
positioned below the third proximal bore 18C and the fourth
proximal bore 18D is positioned below the first proximal bore 18A,
although a variety of respective heights and spacings are
contemplated.
[0039] In one embodiment, the humeral nail 10 is formed of a
bioresorbable material such as polylactide so that the humeral nail
10 does not have to be removed after the fracture F has healed. The
humeral nail 10 may optionally be coated with a bone in-growth
friendly coating, such as hyaluronate to facilitate cell
proliferation and migration, or with an anti-septic coating, such
as cement with an antibiotic.
[0040] The humeral nail 10 also includes a first proximal screw 26A
that is engageable with the first proximal bore 18A, a second
proximal screw 26B that is engageable with the second proximal bore
18B, a third proximal screw 26C that is engageable with the third
proximal bore 18C and a fourth proximal screw 26D that is
engageable with the fourth proximal bore 18D. Each of the screws
26A-26D includes a head portion and a body portion. In the
illustrated embodiment, the head portion has a diameter that is
about two times greater than a diameter of the body portion and has
a substantially flat surface that is connected to the body portion.
This design distributes pressure on the humerus 100 more uniformly.
The body portion of each of the proximal screws 26A-26D is
optionally threaded to aid in maintaining each of the screws
26A-26D within the proximal bores 18A-18D, respectively.
[0041] As can particularly be seen in FIG. 3, the lengths of the
body portions of the screws 26A-26D may vary in length depending on
the anatomy of the patient. The body portion of the first proximal
screw 26A enters at the greater or lesser tuberosity 110, 112
depending on the location of the fracture F, and preferably has a
length such that when fully inserted into the humeral nail 10, the
body portion of the distal end 28 of the first proximal screw 26A
does not substantially extend beyond the humeral nail 10. Thus, the
first proximal screw 26A will affix a fragment of the greater or
lesser tuberosity 110, 112 to the humeral nail 10, but will not
extend to the other side of the humeral nail 10.
[0042] If the distal end 28 of the first proximal screw 26A extends
beyond through the humeral nail 10, the body portion may catch soft
tissue and bone if the humeral nail 10 is rotated within the
humerus 100. Generally, the length of the body portion of the first
proximal screw 26A is sufficient to extend from the cortical wall
of the greater or lesser tuberosity 110, 112 to the central axis CA
of the humeral nail 10. In one embodiment, the first proximal screw
26A is between about 25 millimeters (mm) and about 40 mm long.
Because the humeral nail 10 is substantially linear and the body
portion of the first proximal screw 26A does not extend
substantially past the humeral nail 10, the humeral nail 10 with
the attached bone fragment of the greater or lesser tuberosity 110,
112 can be rotated within the medullary canal M before additional
screws, e.g., proximal screws 26B-26D and distal screws 38, 40 are
inserted into the humeral nail 10.
[0043] Each of the body portions of the second, third and fourth
proximal screws 26B-26D has a length sufficient to pass through its
respective bore 18B-18D to the opposite side of the humeral nail
10. The lengths of the body portions of the second, third and
fourth proximal screws 26A-26D may have varying lengths, but are
generally longer than the first proximal screw 26A.
[0044] The first and second proximal screws 26A, 26B are positioned
through the fragment of the greater or lesser tuberosity 110, 112
and function to reduce the fragment of the greater or lesser
tuberosity 110, 112 and hold the fracture F together. Together, the
proximal end 23 of the humeral nail 10 and the first, second and
third proximal screws 26A-26C maintain the tuberosities 110, 112
and stabilize the fracture F.
[0045] In one embodiment, the proximal end 23 of the humeral nail
10 and the second and third proximal screws 26B, 26C are positioned
in a triangular formation such that the fracture F is stabilized by
three points: the proximal end 23 of the humeral nail 10, the
second proximal screw 26B positioned through a posterior part of
the greater or lesser tuberosity 110, 112 and the third proximal
screw 26C positioned through an anterior part of the greater or
lesser tuberosity 110, 112. In this configuration, the fracture F
is maintained laterally and inferiorly by the tuberosities 110,
112; medially by the glenoid; and superiorly, anteriorly and
posteriorly by the rotator cuff tendon, without requiring the
fourth proximal screw 26D. In addition, the angulation between the
first proximal screw 26A through the greater tuberosity 110 and the
lesser tuberosity 112 is wide enough to reduce the greater or
lesser tuberosity 110, 112 and rotate the humeral nail 10 without
damaging the surrounding bone structures or soft tissues. The
angulation is also wide enough to avoid cuff insertion when
inserting the humeral nail 10 in the humerus 100 and still catch
the greater tuberosity 110 and lesser tuberosity 112 at their
centers.
[0046] The fourth proximal screw 26D functions to support the
humeral head 106 and locks the humeral head 106 in position. While
the humeral nail 10 is discussed as including a fourth proximal
bore 18D and a fourth proximal screw 26D, the fourth proximal bore
and screw 18D, 26D are not necessary for the humeral nail 10 to
properly function and are thus optional. In the preferred
embodiment, no screws are used to secure the humeral head 106. In
particular, the humeral head 106 is retained laterally and
inferiorly by the tuberosities 110, 112, medially by the glenoid
and superiorly, anteriorly and posteriorly by the rotator cuff
tendon (see FIG. 1).
[0047] Referring back to FIGS. 2A and 2B, the distal portion 16 of
the humeral nail 10 includes a first distal bore 34 or 34' and a
second distal bore 36. In the embodiment of FIG. 2A, the distal
bores 34 and 36 are spaced from one another but lie along the same
axial line. In the preferred embodiment of FIG. 2B, the distal
bores 34' and 36 are not lying along the same axial line. In some
embodiments, a neutral axis A is an intersection of a horizontal
plane with a frontal plane containing a central axis CA of the
humeral nail 10. As such, when the patient's arm is in a neutral
rotation position, the neutral axis A is substantially
perpendicular to the forearm. In the embodiments of FIGS. 2A and
2B, the neutral axis A is substantially parallel with an axis
passing through each of the distal bores 34 and 36 and is
substantially perpendicular to the central axis CA, whereas the
axis of the distal bore 34' is at a non zero angle relative to the
neutral axis in either the postero-anterior direction or the
antero-posterior direction. In a preferred embodiment, one of the
distal bore axes is preferably parallel to the neutral axis. In the
vertical plane, the distal bore axis is angulated relative to the
central axis CA. In another preferred embodiment, in the vertical
plane, the distal bore axis is preferably perpendicular to the
central axis CA. As described, the angular locations of the screws
26A-26D are indicated relative to the neutral axis A.
[0048] A first distal screw 38 or 38' is engageable with the first
distal bore 34 or 34' along the axis of the distal bore. A second
distal screw 40 is engageable with the second distal bore 36 along
the axis of the distal bore. The distal screws 38 or 38' and 40 are
preferably designed such that one is static and the other is
dynamic. The first and second distal screws 38 or 38' and 40 are in
dotted lines in FIGS. 3A and 3B so that the first and second distal
bores 34 or 34' and 36 can be seen.
[0049] FIG. 4A shows a schematic view of the proximal portion 14 of
the humeral nail 10 and will be discussed in conjunction with FIGS.
4B, 4C, 4D, 4E, and 5. FIG. 4B shows a top cross-sectional view
through lines A-A of FIG. 4A of the location of the second proximal
bore 18B, FIG. 4C shows a top cross-sectional view through lines
B-B of FIG. 4A of the location of the third proximal bore 18C, FIG.
4D shows a top cross-sectional view through lines C-C of FIG. 4A of
the location of the first proximal bore 18A and FIG. 4E shows a top
cross-sectional view through lines D-D of FIG. 4A of the location
of the fourth proximal bore 18D. As previously mentioned, the
proximal bores 18A-18D are positioned at particular heights and
angles relative to the neutral axis A. The particular heights and
angles allow the humeral nail 10 to bring the greater or lesser
tuberosity 110, 112 of the humerus 100 back to its anatomical
position without damaging the humeral shaft 116 and surrounding
soft tissue. The proximal bores 18A-18D are positioned in a
postero-anterior or antero-posterior direction, also described as
either internally or externally, relative to the neutral axis A of
the humeral nail 10. When the proximal bore 18A-18D is positioned
internally relative to the neutral axis A, the proximal bore
18A-18D is located in a first direction from the neutral axis A.
When the proximal bore 18A-18D is positioned externally relative to
the neutral axis A, the proximal bore 18A-18D is located in a
second direction from the neutral axis A.
[0050] In the embodiment shown in FIG. 5, the second proximal bore
18B is located between about 7 millimeters (mm) and about 11 mm
from the proximal end 23 of the humeral nail 10 and at an angle
relative to the neutral axis A about 30 degrees and 40 degrees,
particularly about 9 mm from the proximal end 23 of the humeral
nail 10 and at an internal rotation of about 35 degrees. In one
embodiment, the third proximal bore 18C is located between about 13
mm and about 17 mm from the proximal end 23 of the humeral nail 10
and at an external rotation of between about 90 degrees and 100
degrees, particularly about 15 mm from the proximal end 23 of the
humeral nail 10 and at an external rotation of about 95 degrees. In
one embodiment, the first proximal bore 18A is located between
about 19 mm and about 23 mm from the proximal end 23 of the humeral
nail 10 and at an internal rotation of between about 50 degrees and
60 degrees, particularly about 21 mm from the proximal end 23 of
the humeral nail 10 and at an internal rotation of about 55
degrees. In one embodiment, the fourth proximal bore 18D is located
between about 24 mm and about 28 mm from the proximal end 23 of the
humeral nail 10 and at an external rotation of between about 25
degrees and 35 degrees, particularly about 26 mm from the proximal
end 23 of the humeral nail 10 and at an external rotation of about
30 degrees. Besides, the axis of the distal bore 34' is at an
external rotation of between 15 degrees to 25 degrees relative to
the neutral axis A.
[0051] In some embodiments, the angles as described above causes
the screw axes to not only be in the tuberosities, but also at the
insertion of the rotator cuff on the tuberosities. This can be
particularly useful in patients with weak bones, where a screw
would only be inserted into bone which it would otherwise pass
through without being retained. Instead, and in accordance with
some embodiments described herein, the angular offsets and relative
positions of the screws facilitate insertion at the insertion
muscle location, where the screws are retained by more solid bone
and the muscle itself.
[0052] The method for reducing and orienting the tuberosities 110,
112 at a humeral fracture site will now be described in detail.
[0053] The humeral nail 10 is introduced through the humeral head
106 and into the medullary canal of the humerus 100. The humeral
nail 10 is preferably inserted in a region of the humeral head 106
offset from the articular surface 106A. In one embodiment, the
humeral nail 10 is introduced into the humerus 100 percutaneously
or using a small superior trans-deltoid approach. The humeral nail
10 is preferably substantially straight which permits it to rotate
after insertion in the medullary canal.
[0054] After the humeral nail 10 is positioned within the humerus
100, an aiming device is used to locate the first proximal screw
26A in one of the greater or lesser tuberosities 110, 112 and into
the first proximal bore 18A. In one embodiment, an aiming device is
attached to the humeral nail 10. The aiming device is preferably
fixed relative to the central axis CA of the humeral nail, although
a rotating aiming device may be used. In one embodiment, the aiming
device is formed of a radiolucent material and allows the surgeon
to see the fracture reconstruction, the location of the humeral
nail 10 and the location of the proximal and distal screws 26A-26D,
38, 40. In another embodiment, the aiming device is attached to the
humeral nail after the humeral nail is introduced into the
medullary canal. Alternatively, the aiming device is an imaging
device.
[0055] The first proximal screw 26A is used to move one of the
tuberosities 110, 112 that has been fragmented toward the proximal
humerus 102. The distal tip 28 (see FIGS. 3 and 5) of the first
proximal screw 26A is preferably not advanced substantially beyond
the humeral nail 10. The first proximal screws 26A is not intended
to go into the humeral head 106, but rather to the border of the
humeral head 106.
[0056] Next, the attached fragment of the greater or lesser
tuberosity 110, 112 is reduced to an anatomically optimal position
by rotation with the humeral nail 10. The fragment of the greater
or lesser tuberosity 110, 112 attached to the humeral nail 10 can
be rotated clockwise or counterclockwise around the central axis CA
without damaging surrounding bony structures and soft tissues.
Depending on the condition of the surrounding bony structure, the
fragment of the greater or lesser tuberosity 110, 112 and the
humeral nail 10 can be rotated between about zero and about 20
degrees, and preferably between about zero and about 40 degrees. In
one embodiment, the fragment of the greater or lesser tuberosity
110, 112 is simultaneously moved towards the proximal humerus 102
and rotated toward an anatomically optimal position.
[0057] In another embodiment, the first proximal screw 26A is only
partially advanced into the first proximal bore 18 in the humeral
nail 10. Only after reduction of the fragment of the greater or
lesser tuberosity 110, 112 to an anatomically optimal location by
rotation of the humeral nail 10 is the first proximal screw 26A
advanced the remainder of its length. Once the first proximal screw
26A is advanced into the humeral head 106, further rotation of the
humeral nail 10 is not advised. Even in the fully engaged position,
the distal end 28 of the first proximal screw 26A preferably does
not penetrate the cortical bone on the articular surface 106A.
[0058] The aiming device is used to insert the remainder of the
proximal screws 26B-26D into the humeral bores 18B, 18C, 18C. Once
the proximal screws 26A-26D are secured through the proximal bores
18A-18D, respectively, the first and second distal screws 38, 40
are secured through the first and second distal bores 34, 36,
respectively, in the distal portion 14 of the humeral nail 10 using
the aiming device.
[0059] Various modifications and additions can be made to the
exemplary embodiments discussed without departing from the scope of
the present invention. For example, while the embodiments
descriconcave articular surface above refer to particular features,
the scope of this invention also includes embodiments having
different combinations of features and embodiments that do not
include all of the descriconcave articular surface features.
Accordingly, the scope of the present invention is intended to
embrace all such alternatives, modifications, and variations as
fall within the scope of the claims, together with all equivalents
thereof.
* * * * *