Note: Descriptions are shown in the official language in which they were submitted.
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ORTHOPAEDIC PLATE AND SCREW ASSEMBLY
RELATED APPLICATIONS
[0001] This application claims the benefit of United States provisional
application Serial No. 60/783,931, filed March 20, 2006 for an "Orthopaedic
Plate
and Screw Assembly," the entire contents of which are incorporated by this
reference.
RELATED FIELDS
[0002] Embodiments of the present invention generally relate to systems
for coupling bone portions across a fracture and, more specifically, to
intramedullary nail or plate and screw assemblies or other stabilizing
structures
and fastening assemblies used to treat fractures of long bones, such as the
femur, humerus, tibia, and various periarticular fractures of these and other
bones.
BACKGROUND
[0003] There are a variety of devices used to treat fractures of the femur,
humerus, tibia, and other long bones. For example, fractures of the femoral
neck, head, and intertrochanteric region have been successfully treated with a
variety of compression screw assemblies, which include generally a compression
plate having a barrel member, a lag screw and a compressing screw. Examples
include the AMBI and CLASSIC compression hip screw systems offered by
Smith & Nephew, Inc. In such systems, the compression plate is secured to the
exterior of the femur, and the barrel member is inserted in a predrilled hole
in the
direction of the femoral head. The lag screw has a threaded end, or another
mechanism for engaging bone, and a smooth portion. The lag screw is inserted
through the barrel member so that it extends across the break and into the
femoral head. The threaded portion engages the femoral head. The
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compression screw connects the lag screw to the plate. By adjusting the
tension
of the compression screw, the compression (reduction) of the fracture can be
varied. The smooth portion of the lag screw is free to slide through the
barrel
member to permit the adjustment of the compression screw. Some assemblies
of the prior art use multiple screws to prevent rotation of the lag screw
relative to
the compression plate and barrel member and also to prevent rotation of the
femoral head on the lag screw.
[0004] Intramedullary nails in combination with lag screws or other screw
assemblies have been successfully used to treat fractures of the femur,
humerus,
tibia, and other long bones as well. A significant application of such devices
has
been the treatment of femoral fractures. One such nailing system is the IMHS
system offered by Smith & Nephew, Inc., and covered at least in part by U.S.
Pat.
No. 5,032,125 and various related intemational patents. Other seminal patents
in
the field include U.S. Pat. Nos. 4,827,917, 5,167,663, 5,312,406, and
5,562,666,
which are all assigned to Smith & Nephew, Inc. A typical prior art
intramedullary
nail may have one or more transverse apertures through its distal end to allow
distal bone screws or pins to be screwed or otherwise inserted through the
femur
at the distal end of the intramedullary nail. This is called "locking" and
secures
the distal end of the intramedullary nail to the femur. In addition, a typical
intramedullary nail may have one or more apertures through its proximal end to
allow a lag screw assembly to be screwed or otherwise inserted through the
proximal end of the intramedullary nail and into the femur. The lag screw is
positioned across the break in the femur and an end portion of the lag screw
engages the femoral head. An intramedullary nail can also be used to treat
shaft
fractures of the femur or other long bones.
[0005] As with compression hip screw systems, intramedullary nail systems
are sometimes designed to allow compression screws and/or lag screws to slide
through the nail and thus permit contact between or among the bone fragments.
Contact resulting from sliding compression facilitates faster healing in some
circumstances. In some systems, two separate screws (or one screw and a
separate pin) are used in order, among other things, to prevent rotation of
the
femoral head relative to the remainder of the femur, to prevent penetration of
a
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single screw beyond the femoral head, and to prevent a sinfgle screw from
tearing
through the femoral neck and head. When an additional screw or pin is used,
however, unequal forces applied to the separated screws or pins can cause the
separate screws or pins to be pressed against the sides of the holes through
which the separate screws or pins are intended to slide. This may result in
binding, which reduces the sliding of the screws or pins through the nail.
Conversely, a problem can result from excessive compression of the femoral
head toward or into the fracture site. In extreme cases, excessive sliding
compression may cause the femoral head to be compressed all the way into the
trochanteric region of the femur.
[0006] Furthermore, overly rigid nails sometimes generate periprosthetic
fractures in regions away from a fracture site. Therefore, it is important
that -
intramedullary nails be adequately flexible in comparison to the bones in
which
they are implanted.
[0007] The harder, generally outer portion of a typical bone is referred to as
cortical bone. Cortical bone is usually a structurally sound load-bearing
material
for support of an implant. A cross-section of a long bone that shows the
typical
anatomical shape of cortical bone generally reveals a non-circular ring of
cortical
bone which surrounds a medullary canal. Accordingly, the medullary canal
generally features a non-circular cross section. Intramedullary nails of the
prior
art, however, are usually round or square in cross-section, and therefore not
anatomically consistent with the cortical bone or the medullary canal. Some
have
addressed this problem by reaming the medullary canal of the bone with a round
reamer in order to cause the nail to fit the cortical bone. This approach,
however,
can remove significant portions of healthy cortical bone.
[0008] The problem of providing an effective load bearing physical
relationship between an implant and cortical bone in the proximal femur has
been
addressed in the art of hip replacement devices. Various hip stems have been
developed which feature generally non-circular cross sections along their
length,
in order better to fit the anatomically shaped cortical bone of the proximal
femur
and thus more evenly and effectively distribute the load between the stem and
the bone. However, none of these hip stems have been incorporated into a nail,
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bone plate, or other implant or stabilizing structure, nor have they been
configured to accept a screw or screws useful in repairing substantially all
of the
portions of the treated bone. Instead, hip stems as a general matter have been
considered as a device for replacing portions of a long bone, and designed and
used for that purpose. For example, the typical application of a hip stem
includes
completely removing a femoral head and neck, implanting a hip stem, and using
the hip stem to support an artificial femoral head.
[0009] In summary, and without limitation, the foregoing shows some of the
shortcomings of the state of the art. in this field. Among other things, what
is
needed is an orthopaedic system that includes a superior sliding screw or
other
mechanism for applying compression across a fracture. Some embodiments
would also provide a sliding screw or other mechanism that obtains adequate
bone purchase while reducing the incidence of cut-out, rotational instability,
and
excessive sliding. An anatomically appropriately shaped implant or other
stabilizing structure for achieving improved cortical bone contact would also
be
advantageous. Where the stabilizing structure is an intramedullary nail
implant,
the nail would provide for reduced reaming and removal of healthy bone. An
improved stabilizing structure may also have a cross-section that provides a
greater area of material on the side of the device that is placed under a
greater
tensile load when it is subjected to a typical bending load. Additionally, an
improved orthopaedic system could include a sliding screw in combination with
intramedullary nails of various designs, or in combination with plates or
other
stabilizing structures. Combinations of any of these with each other, and/or
with
other devices or combinations of them also present opportunities for
advancement beyond the state of the art according to certain aspects and
embodiments of the present invention.
SUMMARY
[0010] Methods, devices and systems according to certain aspects of this
invention allow treatment of bone fractures and other types of maladies using
one
or both of a stabilizing structure for association with a first bone fragment
and a
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fastening assembly for association with a second bone fragment. The
stabilizing
structure may be a plate or other device for at least partial application to
the outer
surface of bone, or an implant for at least partial.implantation within bone.
Such
stabilizing structures may include a proximal section having a transverse
aperture.
[0011] In some embodiments, one or more cross sections of the proximal
section may feature shapes that impart additional strength and resistance to
tension. Such shapes can be provided, for instance, by one or both (i) adding
additional mass in lateral portions of the cross section, and (2)
strategically
adding and reducing mass in the cross section to take advantage of flange
effects similar to the way flanges add structural benefits to I-beams and
channels.
One way to characterize such cross-sections, which can but need not be
asymmetrical with respect to at least one axis, is that they generally feature
a
moment of inertia extending in a lateral direction from a point that is the
midpoint
of a line from a lateral tangent to a medial tangent of the cross section. In
some
structures, that line is coplanar with the axis of the transverse aperture and
coplanar with the cross section and thus defined by the intersection of those
planes. The endpoints of that line can be defined as the intersection of the
line
with tangents to the medial aspect and the lateral aspect of the cross
section,
respectively. In some embodiments, such stabilizing structures may also
include
a transition section to provide a coupling between proximal and distal
sections of
the stabilizing structure. In other embodiments, it is not necessary that the
stabilizing structure include these geometries and/or properties.
[0012] Fastening assemblies of methods, devices and systems according
to certain embodiments of the invention may at least partially extend through
the
transverse aperture of the stabilizing structure and may include an engaging
member and a compression member. The engaging member rriay be a lag
screw or other similar device used to gain purchase in or otherwise engage a
second bone fragment. The engaging member may be able to slide with respect
to the transverse aperture of the stabilizing structure. The engaging and
compression members may be configured such that the compression member at
least indirectly interacts with a portion of the stabilizing structure as well
as a
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portion of the engaging member to enable controlled movement between the first
and second bone fragments. In some embodiments, the compression member at
least partially directly contacts the second bone fragment.
[0013] In some embodiments, methods, devices, and systems of the
present invention include an insert received in the stabilizing structure's
transverse aperture that includes another transverse aperture. In such
embodiments, the fastening assembly may at least partially extend through the
second transverse aperture.
[0014] According to an aspect of the present invention, there may be
provided an apparatus for treating bone maladies, including a stabilizing
structure
associated with a first bone portion, the stabilizing structure including a
first
transverse aperture; a fastening assembly at least partially extending through
the
first transverse aperture, the fastening assembly including an engaging member
and a compression member: the engaging member engaging a second bone
portion; the compression member contacting and interacting with the engaging
member; the compression member contacting the second bone portion; and the
compression member at least indirectly interacting with the stabilizing
structure;
and an insert at least partially extending through the first transverse
aperture and
including a second transverse aperture; the fastening assembly at least
partially
extending through the second transverse aperture.
[0015] According to some embodiments of the present invention, the
compression member facilitates a sliding movement of the engaging member
with respect to the first transverse aperture; and the compression member
facilitates a controlled movement between the first and second bone portions.
[0016] According to some embodiments of the present invention, the
compression member at least indirectly interacts with the insert to facilitate
controlled movement between the first and second bone portions.
[0017] According to some embodiments of the present invention, the
compression member includes a shoulder that abuts against a portion of the
insert.
[0018] According to some embodiments of the present invention, the
controlled movement between the first and second bone portions includes
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substantial preclusion of rotation of the first and second bone portions with
respect to one another.
[0019] According to some embodiments of the present invention, the
controlled movement between the first and second bone portions includes
compressing the first and second bone portions with respect to one another.
[0020] According to some embodiments of the present invention, adjusting
the compression member tensions the engaging member to compress the first
and second bone portions with respect to one another.
[0021] According to some embodiments of the present invention, the
compression member is at least partially nested within a portion of the
engaging
member.
[0022] According to some embodiments of the present invention, the
compression member includes a first threaded portion and the engaging member
includes a second threaded portion; wherein the first and second threaded
portions cooperate with one another such that adjusting the compression
member tensions the engaging member to compress the first and second bone
portions with respect to one another.
[0023] According to some embodiments of the present invention, the insert
snaps into the first transverse aperture.
[0024] According to some embodiments of the present invention, an arm
interacts with an indention to facilitate the insert snapping into the first
transverse
aperture.
[0025] According to some embodiments of the present invention, a ridge
member interacts with an indention to facilitate the insert snapping into the
first
transverse aperture.
[0026] According to another aspect of the present invention, there may be
provided an apparatus for treating bone maladies, including stabilizing
structure
associated with a first bone portion, the stabilizing structure including a
transverse aperture; a fastening assembly at least partially extending through
the
first transverse aperture, the fastening assembly including an engaging member
and a compression member, wherein the engaging member engages a second
bone portion, wherein the compression member contacts and interacts with the
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engaging member, wherein the compression member contacts the second bone
portion, wherein the compression member facilitates a sliding movement of the
engaging member with respect to the first transverse aperture, wherein the
compression. member at least indirectly interacts with the stabilizing
structure to
facilitate controlled movement between the first and second bone portions, and
wherein the controlled movement comprises substantial preclusion of rotation
of
the first and second bone portions with respect to one another as well as
compressing the first and second bone portions with respect to one another;
and.an insert at least partially extending through the first transverse
aperture and
including a second transverse aperture; wherein the fastening assembly at
least
partially extends through the second transverse aperture.
[0027] According to some embodiments of the present invention, the
compression member at least indirectly interacts with the insert to facilitate
controlled movement between the first and second bone portions.
[0028] According to some embodiments of the present invention, the
compression member includes a shoulder that abuts against a portion of the
insert.
[0029] According to some embodiments of the present invention, adjusting
the compression member tensions the engaging member to compress the first
and second bone portions with respect to one another.
[0030] According to some embodiments of the present invention, the
compression member is at least partially nested within a portion of the
engaging
member.
[0031] According to some embodiments of the present invention, the
compression member includes a first threaded portion and the engaging member
includes a second threaded portion, wherein the first and second threaded
portions cooperate with one another such that adjusting the compression
member tensions the engaging member to compress the first and second bone
portions with respect to one another.
[0032] According to some embodiments of the present invention, the
stabilizing structure is a compression plate.
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[0033] According to some embodiments of the present invention, the
stabilizing structure is a periarticular plate.
[0034] According to some embodiments of the present invention, the insert
snaps into the first transverse aperture.
[0035] According to some embodiments of the present invention, the insert
is integral with the stabilizing structure.
[0036] According to another aspect of the present invention, there may be
provided a method for treating bone maladies including the steps of:
associating
a stabilizing structure with a first bone portion, the stabilizing structure
including a
first transverse aperture; engaging an engaging member with a second bone
portion; at least partially inserting an insert through the first transverse
aperture;
the insert including a second transverse aperture; and passing a compression
member at least partially through the second transverse aperture; the
compression member at least indirectly interacting with the stabilizing
structure;
the compression member contacting the second bone portion; the compression
member contacting and interacting with the engaging member; and the engaging
member at least partially extending through the second transverse aperture.
[0037] According to some embodiments of the present invention, a method
for treating bone maladies also includes using the compression member to
facilitate a sliding movement of the engaging member with respect to the
stabilizing structure, the compression member at least indirectly interacting
with
the stabilizing structure to facilitate controlled movement between the first
and
second bone portions.
[0038] According to some embodiments of the present invention, a method
for treating bone maladies also includes associating a guide with the
stabilizing
structure; and using the guide to guide the movement of at least one bone
preparation instrument.
[0039] According to some embodiments of the present invention, the guide
is used to guide the movement of a plurality of bone preparation instruments.
[0040] According to some embodiments of the present invention, the guide
is used to guide the movement of the at least one bone preparation instrument
after the stabilizing structure has been associated with the first bone
portion.
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[0041] According to some embodiments of the present invention, the
engaging member is engaged with the second bone portion after the stabilizing
structure is associated with the first bone portion and after the guide is
used to
guide the movement of the at least one bone preparation instrument.
[0042] According to some embodiments of the present invention, the insert
is at least partially inserted through the first transverse aperture after the
stabilizing structure is associated with the first bone portion.
[0043] According to some embodiments of the present invention, using the
compression member to facilitate a sliding movement of the engaging member
facilitates compressing the second bone portion with respect to the first bone
portion.
[0044] 'Embodiment' as used herein can be considered to mean an aspect
or object of the invention, and vice versa.
BRIEF DESCRIPTION OF DRAWINGS
[0045] FIG. 1 is a perspective view of an intramedullary nail according to
one embodiment of the present invention shown installed in a femur.
[0046] . FIG. 1A is a perspective view of an intramedullary nail according to
one embodiment of the present invention, shown in greater detail than the
intramedullary nail shown in Fig. 1.
[0047] FIG. 1 B is a perspective view of an intramedullary nail according to
another embodiment of the present invention.
[0048] FIG. 1 C is a cross-sectional view of a portion of the nail of FIG. 1
B.
[0049] FIG. 1 D is a perspective view of an intramedullary nail according to
another embodiment of the present invention.
[0050] FIG. 2 is an elevation view of the intramedullary nail of FIG. 1.
[0051] FIG. 3 is a cross-section view of the intramedullary nail of FIG. 2
taken through the line 3-3.
[0052] FIG. 4 is a side view of the intramedullary nail of FIG. 2.
[0053] FIG. 5 is a cross-section view of the intramedullary nail of FIG. 4
taken through the line 5-5.
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[0054] FIG. 6 is a cross-section- of the intramedullary nail of FIG. 4 taken
through the line 6-6.
[0055] FIG. 7 is a perspective view of an intramedullary nail according to an
altemative embodiment of the invention.
[0056] FIG. 8 is a perspective view of an intramedullary nail according to an
altemative embodiment of the invention.
[0057] FIG. 9 is a perspective view of an intramedullary nail according to an
altemative embodiment of the invention.
[0058] FIG. 10 is a perspective view of an intramedullary nail according to
an alternative embodiment of the invention.
[0059] FIG. 11 is a perspective view of an intramedullary nail according to
an altemative embodiment of the invention.
[0060] FIG. 12 is a perspective view of an intramedullary nail according to
an altemative embodiment of the invention.
[0061] FIG. 13 is a cross-section view of the intramedullary nail of FIG. 7
taken through line 13-13.
[0062] FIG_ 14 is a cross-section view of the intramedullary nail of FIG. 8
taken through line 14-14.
[0063] FIG. 15 is a cross-section view of the intramedullary nail of FIG. 9
taken through line 15-15.
[0064] FIG. 16 is a cross-section view of the intramedullary nail of FIG. 10
taken through line 16-16.
[0065] FIG. 17 is a cross-section view of the intramedullary nail of FIG. 11
taken through line 17-17.
[0066] FIG. 18 is a cross-section view of the intramedullary nail of FIG. 12
taken through line 18-18.
[0067] FIG. 19 is a perspective view of a tool according to an embodiment
of the present invention for preparing bone to receive certain devices
according
to certain embodiments of the present invention.
[0068] FIG. 20 is a perspective view of a device which includes a version of
a fastener assembly according to one embodiment of the present invention.
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[0069] FIG. 21 is an exploded view of the intramedullary device and
fastener assembly shown in FIG. 20.
[0070] FIG. 22 is a perspective view of the fastener assembly shown in
FIG. 20.
[0071] FIG. 23 is an exploded view of the fastener assembly of FIG. 20.
[0072] FIG. 24 is an elevation view of the engaging member of the fastener
assembly of FIG. 23.
[0073] FIG. 25 is a side view of the engaging member of FIG. 24.
[0074] FIG. 26 is a cross-section view of the engaging member of FIG. 24
taken through line 26-26.
[0075] FIG. 27 is an end view of one end of the engaging member of FIG.
24
[0076] FIG. 28 is an end view of the other end of the engaging member of
FIG. 24.
[0077] FIG. 29 is an elevation view of the compression device of the
fastener assembly of FIG. 22.
[0078] FIG. 30 is a cross-section view of the compression device of FIG. 29
shown through line 30-30.
[0079] FIG. 31 is an end view of one end of the compression device of FIG.
29.
[0080] FIG. 32 is an end view of the other end of the compression device of
FIG. 29.
[0081] FIG. 33 is a cross-section view of an intramedullary nail and screw
assembly according to another embodiment of the present invention.
[0082] FIG. 34 is a perspective view of a fastener assembly according to
another embodiment of the invention.
[0083] FIG. 35 is a perspective view of the lag screw of the fastener
assembly of FIG. 34.
[0084] FIG. 36 is a perspective view of a fastener assembly according to
another embodiment of the invention.
[0085] FIG. 37 is a perspective view of the lag screw of the fastener
assembly of FIG. 36:
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[0086] FIG. 38 is a perspective view of a fastener assembly according to
another embodiment of the invention.
[0087] FIG. 39 is an exploded view of the fastener assembly of FIG. 38.
[0088] FIG. 40 is a perspective view of a fastener assembly according to
another embodiment of the invention.
[0089] FIG. 41 is an exploded view of the fastener assembly of FIG. 40.
[0090] FIG. 42 is a perspective view of a compression plate according to an
embodiment of the present invention which includes a fastener assembly
according to an embodiment of the invention.
[0091] FIG. 43 is a perspective view of a periarticular plate according to an
embodiment of the present invention which includes a fastener assembly
according to an embodiment of the invention.
[0092] FIG. 44 is a perspective view of a device according to an
embodiment of the present invention used in the context of humeral repair in a
shoulder joint.
[0093] FIG. 45 is a perspective view of a stabilizing structure according to
another embodiment of the present invention.
[0094] FIG. 46 is a perspective view of an insert that may be used in
conjunction with the stabilizing structure shown in FIG. 45.
[0095] FIG. 47A is a side view of an apparatus for treating bone maladies
according to another embodiment of the present invention.
[0096] FIG. 47B is a side view of an apparatus for treating bone maladies
according to another embodiment of the present invention.
[0097] FIGS. 48-60 show various instruments and illustrate various
methodologies that may, in some embodiments, be used to install apparatuses
according to some embodiments of the present invention.
DETAILED DESCRIPTION OF DRAWINGS
[0098] Methods, devices and systems according to embodiments of this
invention may seek to provide improved treatment of femur fractures and other
types of bone maladies. FIGS. 1-6 illustrate various views of one embodiment
of
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an intramedullary nail 100 of the present invention. The intramedullary nail
100
has a longitudinal bore 130 throughout to aid in insertion in the bone. The
intramedullary nail 100 has a proximal section 102, a transition section 104
and a
distal section 106.
[0099] In some embodiments, the proximal section 102 of the particular
structure shown in FIGS. 1-6 may feature an anatomically inspired shape that
corresponds more accurately to typical cortical bone. One version of such
shape
is shown in the cross-sectional view.of the proximal section 102 in FIG. 6.
The
particular cross-section of the proximal section 102 shown in FIG. 6 is
generally
non-circular along at least some portions of its length, and has a lateral
side or
aspect 108 that is larger than a medial side or aspect 109. The lateral side
108
and medial side 109 are joined by a first side 110 and a second side 116. At
the
intersection of the first side 110 with the lateral side 108 is a first
radiused comer
112 and at the intersection of the second side 116 with the lateral side 108
is a
second radiused corner 114. The first side 110, second side 116 and lateral
side
108 are of approximately equal length. The first side 110 and second side 116
are oriented at acute angles relative to the lateral side 108, so that the
medial
side 109 is smaller than the lateral side 108. By having the lateral side 108
larger
than the medial side 109 the rotational stability of the intramedullary nail
100 is
increased, and resistance to bending and twisting can also be enhanced.
[0100] The medial side 109 shown in FIG. 6 can be radiused. As can be
seen in FIG. 4, the radiused medial side 109 protrudes out from the transition
section 104 and continues to the proximal end of the intramedullary nail 100.
The
protrusion of the medial side 109 corresponds to the calcar region of the
femur
and improves the evenness of load distribution between the bone and
intramedullary nail 100.
[0101] Furthermore, the general cross-section geometry of the proximal
section reduces peak stresses in the proximal section. More specifically, the
typical failure mode of an intramedullary nail and screw assembly combination
is
failure of the nail in tension on its lateral side. The tension is created by
bending
moment induced by body weight load that is applied to the screw assembly.
Therefore, it would be beneficial in reducing stress in the proximal section
of a
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nail to include more material on the side of the nail that is in tension, the
lateral
side, to shape the cross section more effectively to enhance strength and
robustness in the lateral area, or both. The design illustrated in FIG. 6
accomplishes this. The lateral side 108 is wider than the medial side 109,
thus
imparting, at least partially, a flange-like effect. Stress per unit area
induced in
the material on the lateral side 108 is less than would be the case if the
lateral
side was featured a smaller cross-sectional area, such as medial side 109.
[0102] A structure according to another embodiment of the invention that
benefits from the same principle is shown in FIGS. 1 B and 1 C, which
illustrate an
intramedullary nail 1100 with a generally circular cross section whose
generally
circular aperture 1128 is disposed other than concentric with the periphery of
the
cross section. In the particular structure shown in these two Figures, the
offset
aperture 1128 is offset toward the medial side 1109 such that a greater
portion of
material is available to take load, and reduce stress, on the lateral side
1108.
Likewise, any cross-section that provides more material on the lateral side of
the
section reduces stress per unit area in the nail on that side.
[0103] Regardless of the particular manner in which material or mass may
be added to some portions of the lateral parts of the cross section of
proximal
portion 102, material may be added and removed from some portions of the
cross section in order to increase the strength and robustness of the lateral
parts,
or both, the effect can be characterized as imparting a moment of inertia to
the
cross section oriented at least partially in the direction of the lateral side
or aspect
108. In some embodiments, the moment of inertia (shown denoted by the letter
M on FIG. 6) can be characterized as extending in a lateral direction, or at
least
partially toward lateral aspect or side 108 from a point P that is the
midpoint of a
line L extending from the intersection 11 of that line with a tangent T1 to
the lateral
aspect 108, to the intersection 12 of that line with a tangent T2 to the
medial
aspect 109. Stated another way, the effect in at least some cases is to create
a
cross section that features a moment of inertia extending in an at least
partially
lateral direction from a center of the cross section. Preferably, that center
can be
a midpoint between the lateral and medial edges of the cross section.
Alternatively, that center can be the center of mass of the cross section. The
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radius of gyration reflected by the moment of inertia, which is a function of
the
square of the distance of the incremental mass from the center, reflects
additional
strength in lateral parts of the proximal portion 102 caused by more mass or
more
strategically placed mass in the cross section. In some structures, line L is
coplanar with the axis of the transverse aperture and coplanar with the cross
section and thus defined by the intersection of those planes. As FIGS. 1 A on
the
one hand, and 1B and IC on the other hand, reflect, and bearing in mind that
these are only three of a myriad of structures that can impart such lateral
additional strength and robustness, the cross section can but need not be
asymmetrical with respect to at least one of its axes. Additionally, the
longitudinal
opening 130 can be located to share its central axis with that of the cross
section,
or it can be offset in order to help impart the lateral strength or for other
purposes.
[0104] In the particular devices shown in FIGS. 1, 1A, and 2-6, the first side
110, second side 116 and lateral side 108 are flat. Altematively, these sides
could be radiused or otherwise not flat. In the embodiments shown in FIGS. 1-
6,
the medial side 109 is radiused, but as one skilled in the art could
appreciate, the
medial side could be flat.
[0105] The proximal section 102 shown in FIG. 1A has a transverse
aperture 118 that receives a fastening or screw assembly 200 (various versions
of which are shown in FIGS. 20-41) through the intramedullary nail 100. One
embodiment of the proximal transverse aperture 118, shown in FIGS. 1-4, is
formed from two overlapping circular apertures 120, 122, where the proximal
circle aperture 120 is smaller in diameter than the distal circle aperture
122. The
proximal circle aperture 120 shown has a shoulder 132 for constraining the
insertion depth of the fastening assembly as will be explained in more detail
below. Various other apertures allowing insertion of various fastening
assemblies
could be used as would be known to those skilled in the art. For example, FIG.
33 illustrates the intramedullary nail with a circular aperture. The
embodiment of
FIG. 33 is described in greater detail below.
[0106] The proximal section 102 illustrated in FIG. 3 has a proximal end
aperture 128. The proximal end aperture 128 is threaded to allow for the
insertion of a set screw that can be used to fix the rotational and sliding
position
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of a fastening assembly. A set screw may also include mechanisms for spanning
a compression member 204 and interfering with an engaging member 204 to
independently restrict the rotation or sliding of the engaging member 204.
[0107] As shown in FIGS. 1-6, the transition section 104 is tapered from the
proximal section 102 to the distal section 106. The tapered nature of the
transition section 104 creates a press fit in the intramedullary canal that
controls
subsidence. The tapered transition section 104 assists in preventing the nail
100
from being pressed further down into the intramedullary canal of the femur
than
intended.
[0108] In the intramedullary nail 100 embodiments shown in FIGS. 1-6, the
cross-section of the transition section 104 is circular, but the cross-section
could
vary as known to those skilled in the art. The cross-section could be
anatomically
derived, similar to the cross-section of the proximal section 102, oval or non-
circular. In the embodiment shown in FIGS. 1-6, the transition section 104
contains a distal transverse aperture 124. The distal aperture 124 allows the
insertion through the intramedullary nail 100 of a distal locking screw for
locking
of the intramedullary nail 100.
[0109] The distal section 106 of the intramedullary nail 100 is generally
cylindrical and is configured to provide a reduced bending stiffness. The
embodiments shown in FIGS. 1-5 include a longitudinal slot 126 through the
center of the distal section 106 that forms two sides 134, 136. The slot
reduces
bending stiffness at the distal end of the intramedullary nail 100 and reduces
the
chances of periprosthetic fractures.
[0110] FIG. 1 D shows an intramedullary nail 100 according to another
embodiment of the invention. This nail features, in its proximal portions, a
noncircular cross section that is symmetrical with respect to its lateral--
medial
axis (in this case, preferably but not necessarily, oval shaped in cross-
section),
and which features a centered longitudinal bore (in this case, preferably but
not
necessarily, circular in cross-section). This nail achieves additional
stability to the
extent it resists twisting in the medullary canal. It also accomplishes the
aim of
placing more mass toward the lateral edge or aspect of the proximal cross
section. Furthermore, it places additional mass toward the medial edge or
aspect,
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and thus provides additional structure that acts as a fulcrum to decrease the
mechanical advantage of the fastening assembly which when loaded is the
component that imposes tensional stress on the lateral edge or aspect.
'[0111] FIGS. 7-18 illustrate intramedullary nails 100 according to other
embodiments of the invention. FIG. 7 illustrates an intramedullary nail 100
having no longitudinal bore throughout.
[0112] FIGS. 8 and 14 illustrate an intramedullary nail 100 having stiffness
reduction slots 140 in the transition section 104 and the distal section 106.
The
stiffness reduction slots 140 reduce the bending stiffness at the distal end
of the
intramedullary nail 100 and could be used to receive locking screws in some
embodiments.
[0113] FIGS. 9 and 15 illustrate an intramedullary nail 100 having three
longitudinal slots 138 in the distal section 106 and a portion of the
transition
section 104 forming a cloverleaf pattem. This pattem more readily permits
blood
flow near the intramedullary nail 100 and also reduces bending stiffness at
the
distal end of the nail 100.
[0114] FIGS. 10 and 16 illustrate an intramedullary nail 100 in which the
distal section 106 and a portion of the transition section 104 have a series
of
longitudinal grooves 146. The longitudinal grooves 146 reduce bending
stiffness
at the distal end, provide rotational resistance, and enhance blood flow near
the
intramedullary nail 100.
[0115] FIGS. 11 and 17 illustrate an intramedullary nail 100 where the
transition section 104 and the distal section 106 have fins 144. The fins 144
provide rotational resistance for the iritramedullary nail 100.
[01161 FIGS. 12 and 18 illustrate an intramedullary nail 100 having barbs
142 located on the distal section 106 and a portion of the transition section
104.
The barbs 142 provide rotational resistance for the intramedullary nail 100.
[0117] Intramedullary nails according to some embodiments of the present
invention may be inserted into a patient by any suitable known technique.
Generally, the intramedullary canal of the bone is prepared with an
appropriate
tool to create a void for insertion of the nail. Some portions of the void may
be
prepared to be about 1 millimeter larger than the perimeter of the nail to
permit
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sufficient space for blood flow after insertion of the nail. A guide pin or
wire is
optionally inserted into the prepared medullary canal. The nail is then
introduced
into the desired position. If the nail is cannulated, the nail can be
introduced over
the guide wire. The position of the nail may be confirmed by image
intensification.
[0118] FIG. 19 shows one embodiment of a tool 300 for preparing a
medullary canal. The tool has a drill bit 302 for reaming and also a mortise
chisel
304. In operation, the drill bit 302 reams out the medullary canal of the
femur and
the mortise chisel 304 cuts out a larger section in the more proximal end of a
bone. As shown in FIG. 19, the mortise chisel 304 has an anatomically derived
cross-section of approximately the same shape as the proximal section of the
intramedullary nail. By applying this type of shaped, mortise chisel, the
proximal
end of the nail will be better enabled to seat on cortical bone that has been
only
minimally altered. The mortise chisel 304 may be of a wide variety of shapes,
even complicated, asymmetrical shapes. This is advantageous because it
enables a device and method for preparing voids able to accept a wide variety
of
shapes of intramedullary nails without merely over-reaming circular voids.
Preparation of an accurately conforming void is valuable in avoiding
unnecessary
removal of healthy bone, and in ensuring stable seating of the nail.
[0119] In operation, the tool 300 of the embodiment shown is advanced as
a unit, with the drill bit 302 reaming and the mortise chisel 304 cutting
simultaneously. The drill bit 302 may be tumed with a power driver, or by
hand.
Likewise, the entire tool 300 may be advanced into a medullary canal manually,
or advanced with the assistance of mechanical advantage or power equipment.
In other configurations, the drill bit 302 may be cannulated (not shown) such
that
the entire tool 300 is operable over and guided by a guide wire that has been
inserted into the medullary canal.
[0120] In other embodiments, the bit for reaming is a more traditional
reamer that is separate from a cutting tool such as the mortise chisel 304.
The
method for preparing a void in such an instance would include first reaming an
opening with a traditional reamer. A device such as a chisel or a broach,
shaped
similar to the intramedullary nail to be implanted, would then be used to
prepare
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the void. The chisel or broach may be driven in by hand, with the assistance
of a
hammer or mallet, or with the use of other power equipment. A nail consistent
with the void prepared would then be implanted.
[0121] Other custom instruments such as a contoured broach or a custom
router bit and template could be used as well. Broaches have long been used to
prepare openings for hip stems, and the use of a broach would be familiar to
one
of skill in the art. A router bit and template could be use, in effect, to
mill out the
desired shape in the bone. Such a method might also be used in combination
with reaming or broaching to create the desired void.
[0122] Intramedullary nails in accordance with some of the embodiments of
the present invention may be used to treat proximal femoral fractures and
femoral
shaft fractures, among other fractures of long bones and other bone maladies.
When used to treat femoral shaft fractures, the intramedullary nail is secured
in
the femur by one or more fastening devices. When used for the treatment of
proximal femoral fractures the intramedullary nail is preferably used in
conjunction with a fastening assembly.
[0123] FIGS. 20 and 21 illustrate an intramedullary nail 100 according to
one embodiment of the present invention used in conjunction with a fastening
assembly 200 according to one embodiment of the present invention. This type
of fastening assembly may be used in a variety of bones and to treat a number
of
indications, but for the purpose of providing an example, it is being
described
here in use with the proximal femur. In general, the fastening assembly is
useful
in any situation where one fragment of a bone is to be drawn back toward or
pushed away from another fragment of the bone in a controlled manner. The
fastening assembly provides the additional advantage of being configurable to
allow sliding of the assembly in a desired direction after the movement of the
bone fragments has been accomplished.
[0124] As shown in FIG. 21, the axis of the proximal transverse aperture
118 in the intramedullary nail 100 is angled relative to the proximal section
102
and in use, is directed towards the femoral head. In this embodiment of the
fastener assembly 200, an engaging member such as a lag screw 202 is used in
conjunction with a compression member, such as a compression screw 204 or a
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compression peg. The screws are configured such that when in use the
circumference of the lag screw 202 partially intersects with the circumference
of
the compression screw 204, so that the compression screw 204 nests partially
within the circumference of the lag screw 202. This particular combination of
lag
screw 202 and compression screw 204 are further illustrated in FIGS. 22
through
32. Briefly, the lag screw 202 shown in these figures is intended to engage
the
femoral head and to slide in the transverse aperture 118 of the nail 100. The
compression screw 204 engages a shoulder or other structure in transverse
aperture 118 and also threads in the portion of lag screw 202 within which
compression screw 204 nests, so that rotation of compression screw 204
controls
sliding of the lag screw 202 relative to the nail 100 and thus compression of
the
femoral head against the fracture site.
[0125] The lag screw 202 shown in these drawings includes an elongate
body 206 and threaded end 208. As shown in FIGS. 24 and 25, the threaded
end 208 does not include a sharp end, which reduces the possibility of cut out
through the femoral head. The elongate body 206 includes a channel 212 that
allows for the positioning of the compression screw 204 partially inside the
circumference of the lag screw 202. The channel 212 includes a threaded
portion 210 that compliments and cooperates with a threaded section 214 of the
compression screw 204. The compression screw 204 includes a threaded
section 214 and a head section 215. The threaded section 214 of the
compression screw 204 is configured such that the threads are relatively flat
and
smooth at the exterior surface so that they can easily slide in the aperture
and
also reduce the possibility of cut out.
[0126] The lag screw 202 is received in the proximal transverse aperture
118 and into a pre-drilled hole in the femur so that the lag screw 202 extends
across the break and into the femoral head. The threaded end 208 of the lag
screw 202 engages the femoral head as the lag screw 202 is rotated within
aperture 118, causing its threaded end 208 to engage the femoral head. The
threaded end 208 may be any device for obtaining purchase in the femoral head,
and includes, but is not limited to, threads of any desired configuration
including
helices, barbs, blades, hooks, expanding devices, and the like. The placement
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depth of the lag screw 202 into the femoral head differs depending on the
desired
compression of the fracture.
[0127] The compression screw 204 can also be received through the
proximal transverse aperture 118 into a predrilled hole in the femoral head.
The
threaded section 214 of the compression screw 204 engages with the threaded
portion of the channel 212 of the lag screw 202. The proximal transverse
aperture 118 has an interior shoulder 132 (FIG. 21) to limit the sliding of
the
conipression screw 204 in the general medial direction and, therefore, the lag
screw 202, through the aperture 118. When the compression screw 204 is
tightened, the compression screw threads 214 engage with the lag screw channel
threaded portion 210 and the compression screw 204 moves in the generally
medial direction down the lag screw 202. The head section 215 of the
compression screw 204 engages the shoulder 132 of the proximal transverse
aperture 118 preventing the compression screw 204 from moving further in the
general medial direction. As the compression screw 204 is tightened, the lag
screw 202 is drawn in the general lateral direction toward the intramedullary
nail
compressing the fracture. The compression screw 204 partially intersecting the
circumference of the lag screw 202 provides greater surface resistance and
aids
in the prevention of femoral head rotation. The compression screw 204
therefore
acts not only as a part of the mechanism for moving fragments of the fractured
bone relative to one another, but also directly contacts bone of the femoral
head
to help prevent the femoral head from rotating about the axis of the lag screw
202. In other embodiments, it is not necessary to use the compression screw
204 (which may also be referred to as a compression member as discussed
below) to compress the fracture, and the fracture may be stabilized simply by
installing the compression screw 204 and lag screw 202 (which may also be
referred to as an engagement member as discussed below).
[0128] In one embodiment, a set screw (not shown), positioned in the
proximal end aperture 128 of the intramedullary nail, is used to engage the
compression screw 204 and fix the compression screw 204 and lag screw 202 in
place. The use of the set screw to fix the fastener assembly 200 in place may
be
fracture pattem dependent. If a set screw is not used to engage the fastener
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assembly, the fastener assembly 200 can slide within the proximal aperture
limited by the shoulder 132.
[0129] In the embodiment of the lag screw and compression screw shown
in FIGS. 20-32, the diameter of the compression screw 204 is smaller than the
diameter of the lag screw 202. In other embodiments, the diameters of the lag
screw and compression screw could be the same or the diameter of the lag
screw could be smaller than the diameter of the compression screw. The threads
of the lag screw and the compression screw could be a variety of different
shapes
as known to those skilled in the art. In general, the purpose of the lag screw
is to
obtain purchase in bone, and the purpose of the compression screw is to engage
with and draw or move the lag screw. Any configuration that permits these
functions is within the scope of the invention.
[0130] The fastener assembly 200 shown in the Figures could additionally
be configured to allow the addition of a prosthetic femoral head and neck. In
such an embodiment, the lag screw 202 would be replaced with a prosthetic head
and neck. The neck would fit into the proximal transverse aperture 118 in the
nail
100. The design would be beneficial where degeneration or re-injury of a
repaired femoral fracture and hip joint later necessitated a total hip
arthroplasty
(THA). The decision to accomplish a THA could be made interoperatively, or
after some period of time. Instead of having to prepare a femur to accept a
hip
stem as is known in association with THA, only a small portion of bone would
need to be removed, along with the fastener assembly 200. The prosthetic head
and neck could then be inserted into the proximal transverse aperture 118, the
acetabuium prepared, and the remainder of the THA completed.
[0131] FIG. 33 is a cross-section view of an intramedullary nail 100
according to another embodiment of the invention with an altemate fastener
assembly 400. The fastener assembly illustrated is very similar to the
compressing fastener assembly of Smith & Nephew's IMHS system, as is more
thoroughly disclosed in U.S. Pat. No. 5,032,125 and various related
international
patents. The improvement of the device illustrated is that it includes the
intramedullary nail 100 with an anatomically derived shape and its multiple
advantages as discussed above. In operation, a sleeve 401 fits through the
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intramedullary nail 100, and may be secured to the nail by set screw, or other
effective mechanisms. A sliding lag screw 402 is able to move axially within
the
sleeve 401. A compressing screw 404 is threaded into the sliding lag screw 402
such that tightening of the compressing screw 404 draws the sliding lag screw
402 back into the sleeve 401. With this mechanism, a bone fragment may be
brought into a desired position, but still permitted to achieve sliding
compression
once positioned.
[0132] FIGS. 34-35 illustrate a fastener assembly 200 according to another
embodiment of the invention having a lag screw 202 and a compression peg 502.
As shown in FIG. 34, the lag screw 202 and the compression peg 502 are
configured such that, when in use, the circumference of the lag screw 202
partially intersects with the circumference of the compression peg 502,
although
in some embodiments the circumferences might be adjacent rather than
intersecting. The lag screw 202 includes an elongate body 206 and threaded end
208. The lag screw 202 has a key 504 on the channel 212. The compression
peg 502 has a slot 503 that is adapted to receive the key 504 of the lag screw
202. The key 504 and slot 503 can be a variety of complimentary shapes, such
as, when considered in cross section, triangular, D-shaped, key-holed and
other
shapes as are apparent to those skilled in the art. In operation, the
compression
peg 502 may be moved relative to the lag screw 202 by a compression tool (not
shown) that applies disparate forces between the compression peg 502 and the
lag screw 202, or between the entire assembly and the intramedullary nail 100.
[0133] In the fastener assembly 200 shown in FIGS. 34-35, the lag screw
202 is received to slide in a proximal aperture of the intramedullary nail so
that
the lag screw 202 extends across the break and into the femoral head. The
threaded end 208 of the lag screw 202 engages the femoral head. Once the lag
screw 200 has been properly engaged with the femoral head, the compression
peg 502 is inserted in the proximal aperture into a predrilled hole in the
femoral
head, in order to prevent further rotation of the lag screw 202 as the slot
503 of
the compression peg 502 receives the key 504 of the lag screw 202. By
providing more area for resistance, the compression peg 502 helps to prevent
the
rotation of the femoral head on the lag screw 202. The compression peg 502 is
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fixed in position in the intramedullary nail 100 by a set screw positioned in
the
proximal end aperture of the nail. The lag screw 202 can slide on the
compression peg 502 through the proximal aperture. In another embodiment, the
compression peg 502 has barbs on its surface.
[0134] A fastener assembly 200 according to another embodiment of the
invention is illustrated in FIGS. 36-37. The fastener assembly 200 of this
embodiment has a compression peg 502 and a lag screw 202 similar to the
embodiment illustrated in FIGS. 34-35, except that the key 504 of the lag
screw
202 and the slot 503 of the compression peg 502 have complimentary ratchet
teeth 506. The compression peg 502 is fixed in position in the intramedullary
nail
by a set screw positioned in the proximal end aperture. Compression of the
fracture can be achieved by pulling the lag screw in the general lateral
direction.
The ratchet teeth 506 allow the lag. screw 202 to move in the general lateral
direction, but prevent the lag screw 202 from moving in the general medial
direction. A compression tool similar to the tool described in association
with
FIGS. 34-35 may be used to accomplish the movement.
[0135] FIGS. 38-39 show a fastener assembly 200 according to another
embodiment of the invention having a lag screw 602, a cross hair screw 610 and
a compression screw 604. The lag screw 602 includes an elongate body 606
and threaded end 608. The elongate body 606 is semi-circular shaped in cross
section. The screws 602, 604, 610 are configured so that the circumference of
the lag screw 602 intersects with the circumferences of the cross hair screw
610
and the compression screw 604. The elongate body 606 of the lag screw 602 is
threaded to compliment and cooperate with a threaded section 602 of the cross
hair screw 610. The cross hair screw 610 is threaded to engage with the lag
screw 602 and the compression screw 604. The compression screw 604
includes a threaded portion 614 and a head portion 612.
[0136] In this embodiment, the lag screw 602, the cross hair screw 610 and
the compression screw 604 are received simultaneously to slide in a proximal
aperture of an intramedullary screw. The lag screw 602 extends across the
break and into the femoral head. The threaded end 608 of the lag screw 602
engages the femoral head. As compression screw 604 is tightened, the threads
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614 of the compression screw engage the threads of the cross hair screw 610
and lag screw 602, thereby moving the lag screw 602 in the general lateral
direction toward the intramedullary nail providing compression to the femoral
head. The cross hair screw 610 is then turned causing the compression screw
604 to move in the distal direction away from the lag screw 602. The fastener
assembly 200 can altematively be configured so that the compression screw 604
moves proximally relative to the lag screw 602. The compression screw 604
separates from the lag screw 602 to help to prevent rotation of the femoral
head
on the lag screw 602 by adding more area for resistance.
[0137] FIGS. 40-41 illustrate a fastener assembly 200 according to another
embodiment of the invention having a lag screw 702 and a compression peg 704.
The lag screw 702 includes an elongate body 706 and a threaded end 708. The
elongate body 706 is semi-circular shaped in order to allow the compression
peg
704 to be positioned partially inside the circumference of the lag screw 702
for
insertion into the femur and has a key 712 positioned on the interior side of
the
elongate body 706. The elongate body 706 also has an aperture 710 through the
body. The compression peg 704 is generally cylindrical and is sized to fit
within
the semi-circular body 706 of the lag screw. The key 712 of the lag screw- is
received by a slot 714 in the compression peg 704. The key 712 and slot 714
contain complimentary ratchet teeth (not shown).
[0138] In this embodiment, the lag screw 702 and the compression peg 704
are received simultaneously to slide in a proximal aperture of an
intramedullary
nail into a pre-drilled hole in the femur. The lag screw 702 extends across
the
break and into the femoral head. The threaded end of the lag screw 702
engages the femoral head. A compression tool similar to the tool describe in
association with FIGS. 34-35 may be used to accomplish movement between the
compression peg 704 and the lag screw 702, or between the entire assembly and
the intramedullary nail 100. A set screw may used to fix the position of the
fastener assembly. The set screw is configured such that when the set screw is
tightened a protrusion on the set screw is received through the slot 710 of
the lag
screw 702 and moves the compression screw 704 away from the lag screw 702.
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The compression screw 704 separate from the lag screw 702 helps to prevent
rotation of the femoral head on the lag screw by adding more area for
resistance.
[0139] FIG. 42 illustrates another embodiment of the invention where a
fastener assembly 200 is employed in cooperation with a compression plate 150.
As illustrated, the devices are being applied to a femur. The various
embodiments of the fastener assembly 200 disclosed above may be used with a
similar compression plate, and various compression plates may be configured to
be applicable to other parts of the anatomy.
[0140] FIG. 43 illustrates another embodiment of the invention where a
fastener assembly 200 is being used with a periarticular plate 170. The plate
and
fastener assembly shown are being applied to a proximal tibia. The various
embodiments of the fastener assembly 200 disclosed above may be used with a
similar periarticular plate and various periarticular plates may be configured
to be
applicable to other parts of the anatomy.
[0141] FIG. 44 illustrates another embodiment of the invention where a
fastener assembly 200 is used in combination with a humeral nail 190. As
illustrated, a head section 212 of compression screw 204 bears against the
humerus to draw compression against the humerus. With the compression force
applied to lag screw 202, and the lag screw 202 affixed to a bone fragment
through its threaded end 208, the bone fragment may be drawn into position for
proper healing. In some circumstances, it may be advantageous to place a
washer or bearing surface (not shown) between the head section 212 and the
humeral bone against which the head section 212 compresses. In yet another
variant, the opening in the humerus may be enlarged such that head section 212
is permitted to penetrate the humerus and bear against a portion of the
humeral
nail 190. In such an embodiment, the fastener assembly 200 would be shorter
than illustrated in FIG. 45 to obtain purchase in the same area of bone with
the
threaded end 208. The various embodiments of the fastener assembly 200
disclosed above may be used with a similar nail and various nails may be
configured to be applicable to other parts of the anatomy.
[0142] FIGS. 45-60 show apparatuses 2000 for treating bone maladies in
accordance with other embodiments of the present invention. The apparatuses
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2000 shown in these figures generally include a stabilizing structure 2002 and
a
fastening assembly 2004. The stabilizing structure 2002 shown in FIG. 45 is a
bone plate, however, in other embodiments, stabilizing structure 2002 may be
other orthopaedic devices for at least partial application to the bony
anatomy,
such as the outer surface of a bone.
[0143] Similar to the intramedullary nails discussed above, the stabilizing
structure 2002 may feature geometries that impart a moment of inertia to a
cross
section of the stabilizing structure 2002 oriented at least partially in the
direction
of a lateral side or aspect of the stabilizing structure 2002, to increase its
strength
and/or robustness. For instance, FIG. 45 shows a stabilizing structure 2002 in
which the proximal portion has a lateral side with an increased mass to impart
additional strength and resistance to tension. In other embodiments, however,
such geometries are unnecessary and stabilizing structure 2002 may feature
other traditional or non-traditional geometries.
[0144] The stabilizing structure 2002 shown in FIG. 45 includes a first
transverse aperture 2006 and a number of additional apertures 2008.
Transverse aperture 2006 extends through a proximal portion of stabilizing
structure 2002, such that it can receive a fastening assembly 2004 and
(optionally) an insert 2010, as discussed further below. The transverse
aperture
2006 shown in FIG. 45 extends through stabilizing structure 2002 at an angle,
such that fastening assembly 2004 will roughly parallel a longitudinal axis of
the
femoral neck when the stabilizing structure 2002 is applied to the proximal
femur
in the manner shown in FIGS. 47A and 47B. In other embodiments, however,
apparatus 2000 can be used to treat bone maladies associated with other parts
of the bony anatomy, and transverse aperture 2006 does not necessarily extend
through stabilizing structure 2002 at an angle.
[0145] The additional apertures 2008 shown in FIG. 45 may be used in
conjunction with bone screws or other types of fastening or anchoring devices
to
secure the stabilizing structure 2002 to the bony anatomy. As discussed
further
below, one or more of the additional apertures 2008 may also be used to
associate the stabilizing structure 2002 with various instrumentation used to
install the apparatus 2000.
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[0146] The transverse aperture 2006 of the stabilizing structures 2002
shown in FIG. 45 may receive an insert 2010 that includes a second transverse
aperture 2012, through which the fastening assembly 2004 may pass. One type
of insert 2010 is shown in FIG. 46 and includes an arm 2014 and a ridge member
2016 that can interact with indentions / grooves 2018 and 2020 in stabilizing
structure 2002 to allow the insert 2010 to be securely snapped into the
transverse
aperture 2006 in stabilizing structure 2002. In other embodiments, the arm
2014
and ridge member 2016 can extend from stabilizing structure 2002 and the
indentions 2018 and 2020 can be located in insert 2010. In some embodiments,
ridge member 2016 may be a clip engaged with two apertures extending at least
partially into insert 2010, as shown in FIG. 46. In still other embodiments,
other
structures, devices, and mechanisms can be used to associate insert 2010 with
stabilizing structure 2002.
[0147] The insert 2010 shown in FIG. 46 also includes a flange 2022 that
can interact with one or more portions of the fastening assembly 2004 in a
somewhat similar manner to the shoulder 132 discussed in conjunction with the
intramedullary nails described above.
[0148] The second transverse aperture 2012 shown in FIG. 46 is formed
from two overlapping circular apertures, where the distal circular aperture is
smaller in diameter than the proximal aperture. In other embodiments, the
proximal aperture's diameter may be smaller than the distal aperture's
diameter,
the apertures may have the same diameter, or the apertures may be formed in
other, such as non-circular, shapes.
[0149] In some embodiments, the use of a modular insert, such as the
insert 2010 shown in FIG. 46, may allow the apparatus 2000 to be installed
into a
patient using minimally or less invasive techniques, such as, but not limited
to,
the techniques described further below. For instance, in some embodiments, the
use of stabilizing structure 2002 in conjunction with a modular insert 2010,
where
the stabilizing structure 2002 is installed first and the modular insert 2010
is
installed later, may reduce the size of the incision necessary for
installation of the
apparatus 2000, as opposed to devices that include a one piece structure in
the
place of the stabilizing structure 2002 and insert 2010.
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[0150] In these or other embodiments, use of a modular insert 2010 in
conjunction with stabilizing structure 2002 may also facilitate a more
accurate
installation of apparatus 2000. For instance, in some embodiments, stabilizing
structure 2002 may be installed prior to certain bone preparation operations,
such
as drilling cavities necessary for receiving fastening assembly 2004 and/or
insert
2010. In such embodiments, the stabilizing structure 2002 may be used to
reference and locate various bone preparation operations to facilitate
drilling
cavities and performing other bone preparation operations accurately with
respect to the already installed stabilizing structure 2002.
[0151] The fastening assembly 2004 used in conjunction with apparatus
2000 shown in FIGS. 45-61 includes an engaging member 2024 and a
compression member 2026. The engaging member 2024 may be positioned
above the compression member 2026 (shown in FIG. 47A), below the
compression member 2026 (shown in FIG. 47B), or in some other aerangement.
Engaging member 2024 can be used to engage a second bone portion, such as
the femoral head shown in FIG. 47A. The compression member .2026 may
contact and interact with the engaging member 2024 to facilitate a sliding
movement of the engaging member 2024 with respect to the transverse
apertures 2006 and/or 2012. The compression member 2026 may also at least
indirectly interact with the stabilizing structure 2002 to facilitate
controlled
movement between the bone portions. When apparatus 2000 is used in
conjunction with an insert 2010, engaging member 2024 may slide with respect
to
transverse aperture 2012 (the sliding of which may be controlled by
compression
member' 2026) and a shoulder of compression member 2026 may interact with
flange 2022 to limit the depth of insertion of the fastening assembly 2004.
[0152] The fastening assembly used in conjunction with stabilizing structure
2002 may be any of the fastening assemblies illustrated in any of the Figures
herein, or may be other types of fastening assemblies, and may function and be
used in similar manners as the fastening assemblies described above in
.onjunction with intramedullary nails.
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[0153] FIGS. 48-60 illustrate instrumentation used in accordance with one
method for installing the apparatus 2000 shown in FIG. 47A, although other
methods are possible and within the scope of the present invention.
[0154] FIG. 48 shows the stabilizing structure 2002 associated with a
handle 2030. The handle 2030 can be attached to the stabilizing structure 2002
using a locking post screw 2032 connected to one of the apertures 2008 (such
as
shown in FIG. 48) or in another manner. Using the handle 2030, the stabilizing
structure 2002 may be inserted percutaneously, keeping soft tissue damage to a
minimum. Once inserted percutaneously, stabilizing structure 2002 may be
secured to an outer surface of the bony anatomy using one or more screws or
other fasteners passing through apertures 2008. In other embodiments,
stabilizing structure 2002 can be secured to the bony anatomy using screws or
other fasteners passing through apertures 2008 at any point during the
installation of apparatus 2000.
[0155] As shown in FIG. 49, the handle 2030 may also receive a targeter
2034. The targeter 2034 shown in FIG. 49 includes an opening 2036 to permit
the insertion of a drill sleeve 2038 (as shown in FIG. 50) as well as other
apertures 2040 for receiving additional fixation tools, devices or other
structures.
In other embodiments, targeter 2034 is integral with.handle 2030. In still
other
embodiments, targeter 2034 is not necessary, and drill sleeve 2038 may be
positioned with respect to the stabilizing structure 2002 in another manner.
For
instance, in some embodiments, drill sleeve 2038 is connected to handle 2030
directly, or 'is formed integrally with handle 2030. -
[0156] The drill sleeve 2038 shown in FIG. 50 extends through the opening
2036 in the targeter 2034 to approximately the transverse aperture 2006
extending through stabilizing stnicture 2002. As shown, the drill sleeve 2038
includes first and second tubular portions 2042 and 2044. Tubular portions
2042
and 2044 may receive a wide variety of tools, instruments, and other items.
[0157] For instance, FIGS. 51 and 52 illustrate the insertion of a guide pin
sleeve 2046 into the first tubular portion 2042, which may be cannulated to
receive a guide pin (not shown). The guide pin may be used to guide the
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movement of subsequent instrumentation or other items placed into one or both
of the tubular portions 2042 and 2044.
[0158] FIGS. 53-54 illustrate the insertion of a compression member drill
guide 2048 into the second tubular portion 2044 to guide the movement of one
or
more drills that will prepare a cavity in the bone for receiving the
compression
member 2026. Similar instrumentation may be used to prepare another (albeit
overlapping in some embodiments) cavity for receiving the engaging member
2024. The same, or different, instrumentation may be used to prepare portions
of
the drilled cavities to receive the insert 2010 as well. For instance, in some
embodiments, there may be four drilling procedures: one to drill a cavity for
receiving the compression member 2026, a second to drill a proximal portion of
that cavity slightly larger to receive, in part, the insert 2010, a third to
drill a cavity
for receiving the engaging member 2024, and a fourth to drill a proximal
portion
of that cavity slightly larger to receive, in part, the other part of the
insert 2010 not
accounted for by the second drilling operation. The order and number of these
drilling procedures are not necessarily important in all embodiments. In some
embodiments, it may be desirable to insert an anti-rotation device 2050 (such
as
shown in FIG. 55) into one or both of the tubular portions 2042 and 2044 to
prevent the bone portions from rotating with respect to one another during the
drilling procedures.
[0159] After the cavity for the engaging member 2024 has been prepared,
the engaging member 2024 may be inserted using an inserter, such as the
inserter 2052 shown in FIG. 56. The inserter 2052 shown in FIG. 56 includes a
long cylindrical body 2054 attached to a T-handle 2056. The inserter 2052 may
be used to drive the engaging member 2024 into the prepared cavity, and also
to
rotate the engaging member 2024 to facilitate engaging the bone, such as the
femoral head. In some embodiments, the inserter 2052 may be cannulated and
include a rod extending along at least a portion of the length of the
cannulation,
with a threaded tip at its end. This threaded tip may interact with threads
(not
shown) inside the head of the engaging member 2024 to connect the inserter
2052 to the engaging member 2024. In other embodiments, power tools may be
employed to help engage the engaging member 2024 with the bone.
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[0160] After the engaging member 2024 is installed, as shown in FIGS. 57-
60, the T-handle 2056 may be removed and the insert 2010 may be slipped over
the cylindrical body 2054 of the inserter 2052 and driven into ptace using
another
inserter 2058. The instrumentation may guide the insert 2010 over the engaging
member 2024 and into the transverse aperture 2006 of the stabilizing structure
2002. The ridge 2016, arm 2014 and indentations 2018 and 2020 discussed
above may allow the insert to be snapped into place in the transverse aperture
2006.
[0161] Subsequently, the compression member 2026 may be installed and
adjusted (as discussed above for the intrameduNary nail, or in other manners)
and the various instrumentation may be removed to complete the installation.
[0162] In accordance with the above-described, or other, methodologies,
an apparatus 2000 may be installed in the following manner. First, one or more
incisions may, be made into the patient proximal the relevant bony anatomy.
Next, the handle 2030 (as assembled to stabilizing structure 2002, as shown in
FIG. 48) may be used to position stabilizing structure 2002 proximate the
relevant
bony anatomy, such as the lateral side of the proximal femur. Next, the
targeter
2034 may be assembled to the handle 2030 as shown in FIG. 49, although, in
other embodiments, targeter 2034 may already have been assembled to handle
2030, or may not even be necessary. Subsequently, the drill sleeve 2038 may be
inserted through targeter opening 2036 (although in other embodiments, drilf
sleeve 2038 may be associated directly with handle 2030 or may be associated
with stabilizing structure 2002 in some other manner), as shown in FIG. 50.
[0163] As shown in FIGS. 51 and 52, a guide pin sleeve 2046 may be
inserted into first tubular portion 2042. Next, a guide pin or wire may be
inserted
through a longitudinally extending aperture in guide pin sleeve 2046, and the
guide pin or wire may engage a portion of the bony anatomy. In some
embodiments, the axis of the guide pin may define the axis of the engaging
member 2024, once the engaging member 2024 is installed. At this point, in
some embodiments, fasteners may be installed through additional apertures
2008 to secure the stabilizing structure 2002 to the bony anatomy, although,
in
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other embodiments, these fasteners may be installed at other points during the
installation.
[0164] FIG. 53 shows the compression member drill guide 2048 being
inserted into the second tubular portion 2044 of the drill sleeve 2038 next.
An
aperture extending through the compression member drill guide 2048 may
receive a drill bit for preparing the bony anatomy to receive the compression
member 2026. Subsequently, the compression member drill guide 2048 may be
removed and a second drill bit may be guided through second tubular portion
2044 to prepare the bony anatomy to receive a portion of an insert 2010. In
other
embodiments, both of these drilling operations may be accomplished using a
single combination drill bit, such as a bit similar to the combination drill
bit
described below. As shown in FIG. 55, an anti-rotation device 2050 may be
subsequently inserted into second tubular portion 2044 such that a distal
portion
of the device 2050 fits into the portion of the bony anatomy prepared for the
compression member 2026 and a proximal portion of the device 2050 fits into
the
portion of the bony anatomy prepared to receive a portion of the insert 2010.
[0965] Subsequently, the guide pin sleeve 2046 may be removed and one
or more drill bits may be guided over the guide pin or wire through the first
tubular
portion 2042 to prepare the bony anatomy to receive the engaging member 2024
and other portions of the insert 2010. In some embodiments, this step may be
accomplished using a combination drill bit that includes two different outer
diameters. In other embodiments, multiple drill bits may be employed.
[0166] Next, the inserter 2052 shown in FIG. 56 may be used to install the
engaging member 2024 and insert 2010, as described above and shown in FIGS.
56 through 60. Subsequently, the compression member 2026 may be installed.
In some embodiments, the compression member 2026 may subsequently be
used to compress the fracture, although in other embodiments, it may not be
necessary or desirable to compress the fracture.
[0167] As those skilled in the art will appreciate, the particular
embodiments of this invention described above and illustrated in the figures
are
provided for explaining the invention, and various alterations may be made in
the
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structure and materials of the illustrated embodiments without departing from
the
spirit and scope of the invention as described above and in the following
claims.
