U.S. patent application number 10/180864 was filed with the patent office on 2002-11-07 for osteotomy guide and method.
This patent application is currently assigned to AMEI Technologies Inc., a Delaware corporation. Invention is credited to Bryant, Richard M..
Application Number | 20020164905 10/180864 |
Document ID | / |
Family ID | 24095462 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020164905 |
Kind Code |
A1 |
Bryant, Richard M. |
November 7, 2002 |
Osteotomy guide and method
Abstract
External fixation apparatus and method are disclosed for use in
osteotomy and other medical procedures. The apparatus includes a
stabilizing portion adapted to be externally coupled to an anterior
portion of a tibial bone. The apparatus also includes an angulation
portion adapted to be externally coupled to another anterior
portion of the tibial bone and coupled to the stabilizing portion.
The angulation portion may be selectively adjustable to angulate a
portion of the tibial bone about an axis of rotation offset from a
longitudinal axis of the tibial bone following an osteotomical
procedure on the tibial bone. An osteotomy guide can be attached to
the external fixation apparatus and used by a physician to create
an osteotomy.
Inventors: |
Bryant, Richard M.;
(Clemmons, NC) |
Correspondence
Address: |
Thomas R. Felger
Baker Botts, L.L.P.
1600 San Jacinto Center
98 San Jacinto Blvd.
Austin
TX
78701
US
|
Assignee: |
AMEI Technologies Inc., a Delaware
corporation
|
Family ID: |
24095462 |
Appl. No.: |
10/180864 |
Filed: |
June 26, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10180864 |
Jun 26, 2002 |
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09525992 |
Mar 14, 2000 |
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6423061 |
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Current U.S.
Class: |
439/894 |
Current CPC
Class: |
A61B 17/152 20130101;
A61B 17/1739 20130101; A61B 17/6416 20130101 |
Class at
Publication: |
439/894 |
International
Class: |
H01R 013/73 |
Claims
What is claimed is:
1. A method for providing treatment for an osteotomy, comprising:
securing an external fixation device to an anterior portion of a
patient's bone; and angulating a portion of the patient's bone
about an axis of rotation of the external fixation device offset
from a longitudinal axis of the patient's bone.
2. The method of claim 1, further comprising angulating at least a
portion of the patient's bone without performing a separate
distraction phase thereon.
3. The method of claim 1, further comprising angulating in
increments by the patient.
4. The method of claim 1, further comprising selectively adjusting
the external fixation device to compress an osteotomy.
5. The method of claim 1, further comprising examining the patient
through a window of the external fixation device using at least one
of radiographic imaging and sonic imaging.
6. An osteotomy guide for placement of an osteotomy, comprising: a
generally rigid member adapted to be releasably coupled to an
external fixation device; a receptacle disposed in the member; and
the receptacle adapted to receive a plurality of instruments that
may be used in an osteotomical procedure on a tibial bone.
7. The osteotomy guide of claim 6, wherein the instruments are
selected from the group consisting of a saw, an osteotome and a
drill.
8. The osteotomy guide of claim 6, further comprising the
receptacle adapted to be generally aligned with an axis of rotation
of the external fixation device.
9. The osteotomy guide of claim 6, further comprising the
receptacle adapted to be generally aligned with a region as
measured between a lateral and medial cortex of the tibial bone
from the axis of rotation as measured proximally to distally.
10. The osteotomy guide of claim 6, wherein the external fixation
device comprises: a first portion adapted to be externally coupled
to an anterior portion of the tibial bone; a second portion adapted
to be externally coupled to another anterior portion of the tibial
bone and coupled to the first portion; and the second portion
selectively adjustable to angulate a portion of the tibial bone
about a center of rotation offset from a center of the tibial bone
following an osteotomical procedure on the tibial bone.
11. The osteotomy guide of claim 6, wherein the receptacle
comprises a plurality of generally circularly spaced apertures
spaced at a distance less than the diameter of the respective
apertures.
12. The osteotomy guide of claim 6, further comprising the rigid
member formed from material selected from the group consisting of
polycarbonate, aluminum, stainless steel, and acrylic.
13. The osteotomy guide of claim 6, further comprising the rigid
member adapted to reside in a window formed within the external
fixation device.
14. The osteotomy guide of claim 6, further comprising the rigid
member releasably coupled to the external fixation device by at
least one screw.
15. The osteotomy guide of claim 6 further comprising: the
receptacle adapted to receive a removable insert; and an insert
adapted to receive a plurality of instruments that may be used in
performing an osteotomy.
16. The osteotomy guide of claim 15, wherein the receptacle
comprises a smooth linear aperture.
17. The osteotomy guide of claim 15, wherein the insert is adapted
to receive a saw, an osteotome or a drill.
18. A method for performing an osteotomy, comprising: aligning a
generally rigid member with at least a portion of an external
fixation device; and penetrating a receptacle adapted to receive a
selected instrument disposed in the member to perform an
osteotomical procedure on a tibial bone.
19. The method of claim 18, further comprising selecting the
instrument from the group consisting of a saw, an osteotome, and a
drill.
20. The method of claim 18, further comprising aligning the rigid
member with an axis of rotation of the external fixation
device.
21. The method of claim 18, further comprising releasably coupling
the member to the external fixation device.
22. The method of claim 18, further comprising placing the rigid
member within a window formed in the external fixation device.
23. The method of claim 18, further comprising coupling the member
to the external fixation device by friction.
24. The method of claim 18, further comprising discarding the
member after performing the osteotomical procedure.
25. The method of claim 18, comprising: placing an insert adapted
to receive instruments into the receptacle; and penetrating the
insert with an instrument adapted to receive a select instrument
disposed in the member to perform an osteotomical procedure.
26. The method of claim 25, further comprising selecting the
instrument from the group consisting of a saw, an osteotome, and a
drill.
Description
RELATED PATENT APPLICATIONS
[0001] This application is a Continuation-in-Part Application of
U.S. patent application Ser. No. 09/525,991 filed by Richard M.
Bryant on Mar. 14, 2000 entitled "Improved High Tibial Osteotomy
Method and Apparatus", now U.S. Pat. No. ______.
TECHNICAL FIELD OF THE INVENTION
[0002] This invention relates in general to the field of medical
devices and more particularly to an improved high tibial osteotomy
method and apparatus.
BACKGROUND OF THE INVENTION
[0003] Procedures such as limb lengthening used to address
congenital or traumatic conditions may include an orthopedic
osteotomical procedure such as a high tibial osteotomy (HTO). For
example, an HTO procedure may be used to treat patients who suffer
from a variety of ailments including varus or valgus deformities;
that is, abnormal positions of a bone of the leg or foot. This
procedure may be used to adjust cartilage wear patterns and/or the
distribution of stress along the tibial and knee areas. Performing
valgus or varus correction typically adjusts the angulation of a
tibial bone and may, in many cases, delay or eliminate the need to
replace a joint such as the knee.
[0004] Proper adjustment of limb angulation desirably includes
adjustment of the bone while the bone is healing. External
stabilization or fixation devices are often used to compress and
properly align an osteotomy during the healing process. Multiple
bone screws, wires and/or pins are often used to provide
compression or to attach an external fixation device which provides
compression, prevents displacement of bone or tissue fragments, and
supports the bone or tissue fragments during healing. These screws,
wires and/or pins may be placed through one or both cortices of
bone to properly position and align the osteotomy.
[0005] Some conventional fixation devices may be used to adjustably
secure a first bone portion above an osteotomy in a position
relative to a second bone portion below the osteotomy.
Unfortunately, some of these devices may require physician
intervention for adjustment, and/or may not allow functional use of
the recovering limb while the limb is healing. For example, these
devices may impair a patient's ability to walk. Furthermore, many
of these devices may impair a physician's ability to monitor the
healing process and/or access the area surrounding the osteotomy.
For example, some conventional fixation devices may block or limit
radiographic, ultrasonic and/or visual examination of a treatment
site.
[0006] In addition, some of these devices include a center of
rotation that is generally aligned with a center of the tibia.
These devices may require additional time for a separate
distraction of the bone before the angulation adjustment process
may begin, which may result in an extended treatment period.
Moreover, these devices may in some cases be used to angulate a
tibia with an osteotomy that is not aligned with an adjustment
angle of the fixation device Such misalignment may not provide an
optimal level of angulation and/or control thereof.
SUMMARY OF THE INVENTION
[0007] From the foregoing, it may be appreciated that a need has
arisen for providing an improved high tibial osteotomy device. In
accordance with the teachings of the present invention, an
apparatus and method are provided that substantially reduce or
eliminate disadvantages and problems of conventional external
fixation devices.
[0008] One aspect of the present invention is represented by a high
tibial osteotomy apparatus. The apparatus preferably includes a
stabilizing portion adapted to be externally coupled to an anterior
portion of a tibial bone. The apparatus may also include an
angulation portion adapted to be externally coupled to another
anterior portion of the tibial bone and coupled to the stabilizing
portion. The angulation portion may be selectively adjustable to
angulate a portion of the tibial bone about a center of rotation
offset from a center of the tibial bone following an osteotomical
procedure on the tibial bone.
[0009] Another aspect of the present invention includes an
osteotomy guide for placement of an osteotomy. The osteotomy guide
has a generally rigid member adapted to be releasably coupled to an
external fixation device. The osteotomy guide may also include a
receptacle disposed in the member. The receptacle is preferably
adapted to receive a plurality of instruments to be used in an
osteotomical procedure on a tibial bone.
[0010] The present invention provides several important advantages.
Various embodiments of the invention may have none, some, or all of
these advantages. The invention may permit a variety of monitoring
activities. For example, the invention includes a window that
allows access and/or visual inspection of the osteotomy. In some
applications, the window may include materials that do not obstruct
one or more imaging wavelengths. For example, the window may
include radiolucent material that is relatively transparent to
x-rays. The invention may be secured to an anterior portion of a
tibial bone, permitting functional use of the recovering limb while
the limb is healing. The invention includes a center of rotation
offset from a center of the tibial bone. Such an advantage may
reduce or eliminate the need for a separate distraction period to
avoid bone impingement before beginning the process of angulation
adjustment. For example, the invention may eliminate the need to
wait for lengthening to be performed before angulation commences.
That is, angulation may commence without waiting the approximately
seven to ten days typically required for a separate lengthening or
distraction period.
[0011] The invention may also allow improved control over
conventional methods. For example, the invention allows a patient
to perform incremental angulation adjustments. These incremental
adjustments desirably promote angulation while reducing the risk of
consolidation or solidification of the bone. Such an advantage also
may reduce the overall treatment time and/or improve the control in
angulation.
[0012] The invention may also permit adjustments to be performed so
that an osteotomy may be properly compressed. The invention also
provides for flexibility in pin placement. The invention may also
be used for treatment for both a patient's left and the right
limbs.
[0013] The invention may also provide guidance to a physician in
performing an osteotomy. For example, the invention may allow
proper alignment of the osteotomy with a center of rotation. Such
an advantage may improve the control and accuracy of the angulation
adjustment process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a more complete understanding of the present invention,
and the advantages thereof, reference is now made to the following
written description taken in conjunction with the accompanying
drawings, in which:
[0015] FIG. 1 is a schematic drawing showing an isometric view of a
high tibial osteotomy device incorporating teachings of the present
invention;
[0016] FIG. 2 is a side view of a high tibial osteotomy device
incorporating teachings of the present invention;
[0017] FIG. 3 is a schematic drawing showing another isometric view
of a high tibial osteotomy device incorporating teachings of the
present invention;
[0018] FIG. 4 is a schematic drawing showing an isometric view of a
high tibial osteotomy device with an extended window incorporating
the teachings of the present invention;
[0019] FIG. 5 is a schematic drawing illustrating a cross-sectional
view of an adjustment portion of the high tibial osteotomy
illustrated in FIG. 3;
[0020] FIG. 6 is a schematic drawing showing an isometric view of
an osteotomy guide incorporating teachings of the present
invention;
[0021] FIG. 7 is a schematic drawing showing a front view of the
osteotomy guide of FIG. 6;
[0022] FIG. 8 is a schematic drawing illustrating a cross-sectional
view of the osteotomy guide of FIG. 7;
[0023] FIG. 9 is a schematic drawing showing an osteotomy guide
that includes an insert;
[0024] FIG. 10 is a schematic drawing showing an osteotomy guide
with an insert positioned in a slot; and
[0025] FIG. 11 is a schematic drawing showing a high tibial
osteotomy device with an extended window incorporating an osteotomy
guide with an insert.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Preferred embodiments of the present invention and its
advantages are best understood by referring to the FIGS. 1-11 of
the drawings, like numerals being used for like and corresponding
parts of the various drawings.
[0027] One embodiment for an HTO device 10 incorporating various
features of the present invention is discussed in detail in
conjunction with FIGS. 1-5. HTO device 10 may be used in the
performance and/or in the treatment of high tibial osteotomical
procedures. HTO device 10 is operable to attach to an anterior
portion of tibia 122 of a patient and, in some applications, a
physician may perform the osteotomy after HTO device 10 is attached
to tibia 122. A physician may also use an osteotomy guide to
perform the osteotomy. One embodiment of an osteotomy guide
incorporating various features of the present invention is
discussed in detail in conjunction with FIGS. 6-8.
[0028] HTO device 10 may be used to control the adjustment in
angulation to tibia 122 about a center or axis of rotation offset
from longitudinal axis or longitudinal centerline 142 of tibia 122.
FIG. 1 illustrates a tibia 122 that includes a generally transverse
osteotomy 132 whose penetration through tibia 122 stops short of
lateral cortex 124.
[0029] Satisfactory healing of the bone generally requires
reduction and fixation of osteotomy 132. For example, immediately
after an osteotomical procedure, the osteotomy surfaces are
preferably disposed adjacent to each other, and compression
preferably provided at the osteotomy site to increase the area of
contact between the osteotomy surfaces. Ideally, flexibility in
placement and adjustment of fixation devices may improve control of
the compression process. In this embodiment, HTO device 10 may be
attached to tibia 122 by means of stabilizing devices or pins 22.
HTO device 10 is disposed substantially externally to the body of
the patient (not explicitly shown). Each pin 22 penetrates the body
of the patient at a desired location and is connected to tibia 122.
HTO device 10 may be attached to tibia 122 to both stabilize
osteotomy 132 and permit control of angulation of tibia 122. In the
embodiments illustrated in FIGS. 1 and 2, HTO device 10 is operable
to control angulation of a medial portion 126 of tibia 122 while
callus tissue 128 forms therein.
[0030] FIG. 1 is a schematic drawing showing an isometric view of a
high tibial osteotomy device incorporating teachings of the present
invention. HTO device 10 preferably includes an angulation portion
20 and a stabilizing portion 70. Angulation portion 20 may be used
in conjunction with stabilizing portion 70 to apply gradual
correction angulation means to and control final limb alignment of
tibia 122.
[0031] By way of example and not by limitation, angulation portion
20 includes a proximally located first portion 24, and at least one
clamp mechanism 36 that is releasably coupled thereto. HTO device
10 is shown with an adjustment angle .theta. of approximately zero
degrees, where adjustment angle .theta. is formed in an x-y plane
formed by a y axis through hinge 28 and relative to an x axis
through hinge 28 generally parallel to surface 29 of first portion
24. Thus, HTO device 10 is operable to angulate tibia 122 about a
center of rotation centered at hinge 28 that is offset from center
142 of tibia 122. Angulation portion 20 also comprises an
adjustment portion 40 that is operable to adjustably couple first
portion 24 to distally located second portion 26.
[0032] Adjustment portion 40 may be selectively adjusted to
increase or decrease adjustment angle .theta.. This adjustment
pivots about hinge 28 and results in expansion of medial portion
126 of tibia 122. By way of example and not by limitation,
adjustment angle .theta. may be selectively expanded by rotating
hex socket 42. One example of such an expansion of adjustment angle
.theta. is illustrated and discussed in further detail in
conjunction with FIG. 4. Adjustment portion 40 is disposed on an
exterior side of angulation portion 20 relative to the patient in
this embodiment. The invention also contemplates an adjustment
portion 40 disposed interiorly (relative to the patient) to
angulation portion 20.
[0033] Also by way of example and not by limitation, angulation
portion 20 includes a second portion 26 that is hingedly coupled to
first portion 24 by hinge 28. Hinge 28 may be implemented using a
variety of methods. In this embodiment, hinge 28 may include a
cylindrical pin 27 that rotatably couples cylindrically-shaped
receptacles in both second portion 26 to first portion 24. The
present invention also contemplates the use of other hingeable,
pivotable or rotatable means to couple second portion 26 to first
portion 24.
[0034] First portion 24, second portion 26, and adjustment portion
40 form and enclose a window 60. Window 60 provides an unobstructed
view of tibial bone 122 that desirably allows examination of and/or
access to osteotomy 132. For example, the physician and/or the
patient may palpitate, visually inspect and/or monitor healing of
the wound created by osteotomy 132 through window 60. In addition,
window 60 permits an unobstructed view of osteotomy 132 and callus
portion 128 for a variety of examination and monitoring procedures.
Such an advantage allows a variety of examination techniques to be
used to observe the healing processes of osteotomy 132 and/or
valgus and/or varus correction of bone 122 during treatment. For
example, procedures including, but not limited to, radiographic
imaging (e.g., fluoroscopic, x-ray, magnetic resonance imaging, and
computed tomography scanning techniques) and ultrasonic imaging may
be used to capture unobstructed views of callus portion 128 at a
variety of points during the healing process as tibial bone 122 is
angulated.
[0035] In some applications, it may be desirable for some or all of
the elements within angulation portion 20 to be manufactured using
a variety of composite materials. For example, those elements
forming and enclosing window 60 may include radiolucent materials
that are transparent to radiographic wavelengths. Such an
embodiment provides the advantage of a larger unobstructed imaging
area through which a physician may obtain images to analyze the
healing process. In this embodiment, stabilizing portion 70
includes a support member 71 that may be releasably coupled to
second portion 26 as discussed in further detail in conjunction
with FIGS. 2 and 3. In other applications, second portion 26 and
stabilizing portion 70 may include a single integrated member.
Stabilizing portion 70 also includes clamp mechanisms 76A and 76B.
Clamp mechanism 76A may include one or more portions and may also
be releasably coupled to support member 71 as discussed in
conjunction with FIGS. 2 and 3.
[0036] HTO device 10 may be anteriorly mounted on tibia 122 by
means of at least four pins 22 as shown in the embodiment
illustrated in FIG. 1. Two proximal pins 22 are located above
osteotomy 132, and two distal pins 22 are located below osteotomy
132 a distance D from proximal pins 22. The present invention
contemplates the use of more or fewer pins. For example, in some
applications it may be desirable to utilize three distal pins 22.
The present invention also contemplates the use of other means of
attaching HTO device 10 to tibia 122. For example, HTO device 10
may be connected to tibia 122 using stabilizing devices including,
but not limited to, bone screws, wires, pins or a combination
thereof. Pins 22 may be manufactured using any suitable implantable
grade materials.
[0037] As illustrated in FIG. 1, proximal pins 22 are releasably
secured within a slot or receptacle 38 formed within each of two
clamp mechanisms 36. Also by way of example and not by limitation,
stabilizing portion 70 includes at least one clamp mechanism
operable to secure HTO device 10 to at least two distal pins 22. In
this embodiment, stabilizing portion 70 includes clamp mechanisms
76A and 76B. Clamp mechanism 76B may be releasably secured to clamp
mechanism 76A by adjusting cap screws 72. A plurality of slots or
receptacles 78 may be formed when clamp mechanism 76A is coupled to
clamp mechanism 76B. Receptacles 78 may be generally linearly
aligned as illustrated, staggered in other configurations, and/or
be disposed in either or both clamp mechanisms 76A and 76B. Distal
pins 22 may be releasably secured within at least two receptacles
78.
[0038] A variety of methods may be used to selectably adjust the
placement of pins 22 in, and pressure applied to, tibia 122. In
this embodiment, each clamp mechanism 36 may be selectively
positioned in a slot or track 31 disposed in surface 29. By way of
example and not by limitation, each clamp mechanism 36 may be
translated along first portion 24, and may be releasably fixed
using cap screw 32. The present invention also contemplates the use
of a single slot 31 in which both clamp mechanisms 36 may be
positioned, or other mechanisms for adjusting placement of proximal
pins 22. Each of these elements in angulation portion 20 may reside
in a volume whose surface generally corresponds with a contour of a
patient's lower leg. Such a configuration may be desirable in
applications where placement of pins 22 may be selectively
adjustable. Alignment and adjustment of distal pins 22 is discussed
in conjunction with FIGS. 2 and 3.
[0039] In operation, a physician may first align and then stabilize
HTO device 10 with respect to tibia 122 by inserting one or more
K-wires (not explicitly shown) through receptacles 11 into tibia
122. In addition, the physician may also insert one or more K-wires
through a receptacle in pin 27 into tibia 122. The physician may
then accurately position proximal screws 22 and then distal screws
22. In some embodiments, the physician may also releasably couple
an osteotomy guide 200 to HTO device 10. Osteotomy guide 200 may be
used to assist the physician in performing the osteotomical
procedure, and is discussed in further detail in conjunction with
FIGS. 4-6.
[0040] FIG. 2 is a side view of a high tibial osteotomy device
incorporating teachings of the present invention. Where osteotomy
132 is a medial osteotomy 132 on a right tibial bone 122, FIG. 2
illustrates a medial view of HTO device 10. In this embodiment,
first portion 24 is rotatably coupled to a generally u-shaped
second portion 26 by hinge 28 (not explicitly shown). One of
proximal pins 22 is secured by clamp mechanism 36. By way of
example and not by limitation, cap screws 78 are positioned in a
slot or track 79 on a side 84 of support member 71. Set screws 78
may be used to adjust and releasably couple clamp mechanism 76A to
side 80 (not explicitly shown) of support member 71. Such
adjustment may be used to position distal pins 22 in tibial bone
122 as desired. In this embodiment, this adjustment may be
performed by adjusting and fixing the position of cap screws 78 in
slot 79. Clamp mechanisms 76A and 76B are discussed in further
detail in conjunction with FIG. 3.
[0041] HTO device 10 is positioned at a distance H from tibial bone
122 and substantially externally to the body of the patient (not
explicitly shown). Distance H may vary as desired, and/or according
to the length of proximal and distal pins 22. For example, distance
H may sized to reduce the profile of HTO device 10, while remaining
sized large enough for palpitating the wound created by osteotomy
132 in a region between HTO device 10 and the patient's body. Such
an advantage provides an unobstructed view of tibial bone 122 from
both a medial and a lateral view that, in addition to window 60,
also desirably allows examination of and/or access to osteotomy
132. Such an advantage allows a variety of examination techniques
to observe the healing processes of osteotomy 132 and/or valgus
and/or varus correction of bone 122 during treatment, such as
radiographic and sonic imaging.
[0042] FIG. 3 is a schematic drawing showing another isometric view
of a high tibial osteotomy device incorporating teachings of the
present invention. By way of example and not by limitation, clamp
mechanism 76A is releasably coupled to side 80 of support member 71
by cap screws 78. In some applications, clamp mechanism 76A may
alternatively be releasably coupled to side 84 of support member
71. Second portion 26 and first portion 24 also include surfaces 62
and 64, respectively.
[0043] Clamp mechanisms 36 may be selectively positioned in slot or
track 31 by a variety of methods. In this embodiment, cap screws 32
may be tightened to a nut 34 that is larger than slot 31 to retain
clamp mechanisms 36. Alternatively, other methods and devices may
be used to tighten clamp mechanisms 36 to slot 31 including, but
not limited to, bolts and threaded devices.
[0044] In this embodiment, distal pins 22 may be aligned and
adjusted in at least two ways. First, a generally lateral position
of stabilizing portion 70 with respect to angulation portion 20 may
be adjusted in one or more slots 81 residing in second portion 26.
For example, bolts 82 may be used to position and tighten support
member 70 to slot 81. Second, the positions of distal pins 22 may
also be adjusted to, for example, apply compression to osteotomy
132. For example, the distance D between proximal pins 22 and
distal pins 22 may be selectively expanded or contracted in a
length and a direction generally parallel to tibia 122. In this
embodiment, this adjustment may be performed by adjusting the
position of clamp mechanisms 76A and 76B in slot 79 and fixing the
position thereof by using cap screws 78. The invention also
contemplates a variety of other methods to releasably couple clamp
mechanism 76A to stabilizing portion 70.
[0045] As hex socket 42 is rotated, the length L of adjustment
portion 40 increases. Thus, adjustment portion 40 is desirably
operable to rotatably couple to angulation portion 20 by using
upper screw 58 and lower screw 59 to allow for such an increase.
Upper screw 58 is operable to couple to a threaded boss portion 43
of upper cap 44, and lower screw 59 is operable to couple to a
threaded boss portion 47 of body 48. Bosses 43 and 47 may desirably
be inserted through receptacles (not explicitly shown) of first
portion 24 and second portion 26, respectively. Such a
configuration may distribute any load applied to adjustment portion
40, thus reducing the possibility of failure by screws 58 or 59.
Angulation portion 40 is discussed in further detail in conjunction
with FIG. 5.
[0046] HTO device 10 may be manufactured using a variety of
materials with suitable tensile properties such as, but not limited
to, steel or a polymeric plastic. That is, HTO device 10 may
utilize materials suitable to withstand the stresses that may be
associated with compression and selective adjustment during
treatment of the patient.
[0047] In operation, HTO device 10 may be used for a period of time
suitable for healing. A physician may provide a treatment plan that
includes continuous treatment or treatment at various intervals.
For example, a patient may be instructed to adjust HTO device 10 by
operating hex socket 42 in small increments, a number of times
daily. Hex socket 42 is proximally disposed and easy for a patient
to operate by rotating either clockwise or counterclockwise. Such
an advantage also provides immediate angulation of osteotomy 132,
thus reducing the effective treatment period required. That is, the
patient need not wait for a lengthening or distraction period to be
completed before angulation begins, as with most conventional
anteriorly-placed HTO devices 10.
[0048] It may be particularly advantageous for the patient to
rotate hex socket 42 one-quarter turn four times per day. This
schedule may provide approximately one millimeter (1 mm) of
adjustment per day. Such an advantage may prevent or reduce the
risk of bone consolidation or solidification, while allowing bone
regeneration. This may also permit full desired angulation to be
achieved. The treatment plan may be changed over the course of
healing, and may vary from patient to patient. For example, those
patients who are younger and/or healthier may increase the amount
of rotation and/or the daily repetition thereof.
[0049] The patient may adjust HTO device 10 to enlarge distance D
and length L in accordance with the treatment plan. Such
enlargement provides valgus and/or varus correction by angulating
bone 122 as proximal pins 22 are separated further from distal pins
22. For example, the physician may determine that valgus and/or
varus correction requires extension of distance D to a new distance
D', and/or adjustment of adjustment angle .theta. to a new angle
.theta.'. One example for such an extension is discussed in further
detail in conjunction with FIG. 4.
[0050] FIG. 4 is a schematic drawing showing an isometric view of a
high tibial osteotomy device with an extended window incorporating
the teachings of the present invention. Distance D between proximal
pins 22 and distal pins 22 (as illustrated in FIG. 1) has been
extended to a new distance D'. In addition, length L of adjustment
portion 40 (as illustrated in FIG. 1) has been extended to a new
length L'. In this embodiment, threaded rod 50 has been rotated by
operating hex socket 42 to separate upper cap 44 from body 48.
Rotation of threaded rod 50 rotates adjustment angle .theta. about
the axis of rotation at hinge 28. Adjustment angle .theta. (as
discussed in FIG. 1) has increased to an angle 0' that is between
0.0 degrees and 90.0 degrees.
[0051] Window 60 has also been enlarged by adjustment of adjustment
portion 40. A variety of techniques may be used to accommodate an
increase and/or decrease in adjustment angle .theta. as length L is
increased. For example, proximal and distal pins 22 maintain
positioning of HTO device 10 in tibial bone 122. In addition, in
this embodiment, adjustment portion 40 slightly rotates relative to
first portion 24 and second portion 26. Upper screw 58 and lower
screw 59 allow slight rotation of adjustment portion 40 relative to
first portion 24 and second portion 26, respectively.
[0052] FIG. 5 is a schematic drawing illustrating a cross-sectional
view of an adjustment portion of the high tibial osteotomy
illustrated in FIG. 3. The invention contemplates a variety of
configurations for adjustment portion 40. For example, adjustment
portion 40 includes hex socket 42 which is rigidly connected to a
threaded rod 50. In operation, as a patient rotates hex socket 42,
threaded rod 50 rotates and lifts hex socket 42 a distance from
body 48. Threaded rod 48 may in some applications be a lifting rod
that is manufactured to provide lifting capability.
[0053] In this embodiment, adjustment portion 40 includes upper cap
44, barrel 46, and body 48. Threaded rod 50 is also rigidly
connected by, for example, pin 53, to a socket-containing member 52
which rotates within cap 44. A nut 54 is rigidly connected to body
48. Adjustment portion 40 may also include a means to stop or limit
the distance that threaded rod 50 may be moved relative to body 48.
For example, it may be desirable in some applications for threaded
rod 50 to include a pin 56 that protrudes from threaded rod 50.
This pin may travel in the threads of body 48 and stop the movement
of threaded rod 50 through nut 54. Other methods and devices may be
used to rigidly connect various components including, but not
limited to, gluing and/or welding techniques.
[0054] In some embodiments, it may also be desirable to reduce or
prevent slippage of threaded rod 50. For example, socket-containing
member 52 may include one or more grooves (not explicitly shown)
disposed in a direction generally parallel to length L. These
grooves may extend the entire length of socket-containing member
52, or some portion thereof. A ball plunger assembly 57 may be used
in conjunction with these grooves. For example, ball plunger
assembly 57 includes a threaded rod in which a ball or other
protrusion resides. When a patient rotates hex socket 42, threaded
rod 50 and socket-containing member 52 may move relative to ball
plunger assembly 57, depressing the ball or protrusion into the
groove of socket-containing member 52. When the next groove is
reached, the ball protrudes from the threaded rod into the groove,
effectively limiting movement of threaded rod 50 by means of
friction. In one embodiment of the invention and as illustrated in
FIG. 5, ball plunger assembly 57 may be disposed within upper screw
58 that has been adapted to receive the threaded rod.
[0055] In some embodiments, it may also be desirable to provide a
patient with tactile and/or audible feedback as the patient
operates hex socket 42. As one example, ball plunger assembly 57
may be used to provide such feedback. It may be desirable for the
grooves to be disposed in socket-containing member 52 at
ninety-degree intervals. Such a configuration may allow tactile
and/or audio feedback when threaded rod 50 is rotated in a
one-quarter turn increment. For example, as the ball protrudes into
the groove, it may make an audible click that may be used to signal
the patient that one quarter turn of hex socket 42 has been
achieved. In some applications, it may be desirable to use a ball
plunger assembly 57 with a ball whose diameter is one-quarter the
diameter of threaded rod 50.
[0056] The present invention may be utilized for both the right and
left limbs for both medial and lateral osteotomies. That is,
angulation portion 20 may be used in conjunction with stabilizing
portion 70 to control final limb alignment and apply gradual
correction angulation means to either tibia 122. Such an advantage
may desirably improve the interchangeability of elements for HTO
device 10 and may reduce manufacturing costs. In the embodiment
illustrated in FIGS. 1-4, HTO device 10 may be used in the
correction of a laterally-positioned transverse osteotomy 132 on a
left tibia 122.
[0057] HTO device 10 may be operated in similar fashion for a
medially-positioned or laterally-positioned osteotomy 132 for
either leg. For example, angulation portion 70 may be controlled on
either side of the patient's leg by appropriately reversing the
center of rotation. To reverse the center of rotation, angulation
portion 20 may be rotated and selected elements may be releasably
coupled thereto in an alternative configuration. For example,
stabilizing portion 70 may be coupled to first portion 24, rather
than second portion 26, of angulation portion 20. Thus, in this
embodiment, second portion 26 would be proximally located and first
portion 24 would be distally located.
[0058] Support member 79 may then be coupled to slot 31 of first
portion 24, rather than second portion 26, of angulation portion
20. Clamp mechanisms 36 may also be coupled to slot 81 of second
portion 26, rather than first portion 24, of angulation portion 20
so that they are once again proximally located. Similarly, clamp
mechanisms 76A and 76B may be releasably coupled to side 84 of
stabilizing portion 70. Clamp mechanisms 36, 76A and 76B may also
be similarly selectively adjusted so that pins 22 may be
appropriately positioned, as discussed in conjunction with FIGS.
1-3.
[0059] In addition, adjustment portion 40 may also be flipped to
proximally locate hex socket 42. That is, cap 44 would be coupled
to second portion 26, and body 48 would be coupled to first portion
24. A screw 58 including a ball plunger assembly may also be used
to couple cap 44 to second portion 26, if desired.
[0060] FIGS. 6-8 illustrate an example of an embodiment for an
osteotomy guide. Osteotomy guide 200 may be used by a physician to
create an osteotomy 132, and to improve the accuracy of tibial
angulation by aligning osteotomy 132 with the center of rotation
for HTO device 10. For example, osteotomy 132 may be created in
tibia 122 at a location generally even with hinge 28. Such
alignment may improve the angulation of tibia 122 and control
thereof. Osteotomy guide 200 may desirably be removably inserted
between first portion 24 and second portion 26 to perform an
osteomatic procedure. After the procedure is complete, the
physician may remove and discard osteotomy guide 200.
[0061] FIG. 6 is a schematic drawing showing an isometric view of
an osteotomy guide incorporating teachings of the present
invention. Osteotomy guide 200 preferably includes an inner surface
202, an outer surface 204, first surface 206, second surface 208,
and two edges 210. Osteotomy guide 200 also preferably includes
receptacle 220, which may be generally parallel with first and
second surfaces 206 and 208. Osteotomy guide 200 also preferably
includes two receptacles 212. In some applications, osteotomy guide
200 may reside in a volume whose surface is generally contoured to
that of HTO device 10. In this embodiment, inner surface 202 and
outer surface 202 is generally concavely shaped relative to tibia
122.
[0062] Osteotomy guide 200 may be formed from any semi-rigid
material including, but not limited to, polycarbonate, aluminum,
stainless steel, and/or acrylic. In some applications, osteotomy
guide 200 may desirably be transparent or clear. Use of such
materials may improve a physician's ability to view and/or control
the osteotomy procedure.
[0063] FIG. 7 is a schematic drawing showing a front view of the
osteotomy guide of FIG. 6. FIG. 7 illustrates a scalloped and
generally linear receptacle 220 that is generally parallel to first
surface 206 and second surface 208. The present invention also
contemplates the use of other orientations and/or shapes for
receptacle 220 such as an arc shape.
[0064] Receptacle 220 is desirably disposed at a location within
osteotomy guide 200 to align with hinge 28 of HTO device 10. In the
embodiment shown, receptacle 220 is disposed nearer to first
surface 206 than to second surface 208. Such a configuration also
provides a separation between receptacle 220 and HTO device 10
suitable for tools such as a drill. In this embodiment, receptacle
220 includes a plurality of generally circular receptacles that are
each adapted to receive a drill bit. This plurality of circular
shaped receptacles may be equally spaced from center to center, and
may facilitate creation of a generally linear osteotomy that
comprises a series of holes that are drilled into tibia 122. An
osteotome or chisel may be used to further separate the bone tissue
between the drilled holes, completing the osteotomy 132. The
present invention contemplates a variety of sizes for any number of
receptacles. For example, receptacle 220 may include eleven drill
receptacles each approximately six millimeters (6 mm) in diameter,
spaced approximately 4.8 mm from center to center. The present
invention also contemplates a variety of receptacles 220 through
which a variety of cutting mechanisms such as saw blades may
penetrate to form osteotomy 132.
[0065] FIG. 8 is a schematic drawing illustrating a cross-sectional
view of the osteotomy guide of FIG. 7. Osteotomy guide 200 may be
releasably coupled to HTO device 10 using a variety of methods. In
this embodiment, osteotomy guide 200 may be snugly coupled to HTO
device 10 by means of a screw (not explicitly shown).
[0066] By way of example and not by limitation, osteotomy guide 200
comprises a generally U-shaped notch 214 that generally forms to
surfaces 62 or 64 of second portion 26. As illustrated, notch 214
includes an inner portion 214a that is shorter than an outer
portion 214b. Osteotomy guide 200 may be releasably coupled to HTO
device 10 by placing notch 214 over surfaces 62 or 64. For example,
osteotomy guide 200 may be translated along surface 62 until a
desirable position has been reached. Then, screws (not explicitly
shown) may be inserted through receptacles 212 to penetrate portion
214b and snugly couple second portion 26 to inner portion 214a.
After the osteotomical procedure has been performed, the physician
may unscrew osteotomy guide 200 from HTO device 10 and/or discard
osteotomy guide 200.
[0067] FIGS. 9-11 illustrate an alternative embodiment of an
osteotomy guide incorporating teachings of the present invention.
FIG. 9 shows osteotomy guide 250 having a generally rectangular
configuration with a generally linear, smooth slot 252. Slot 252
may be used as an instrument insertion slot and extends from the
front face of osteotomy guide 250 to the back surface of osteotomy
guide 250. Slot 252 allows a drill guide (not expressly shown) to
be positioned through slot 252 at different angles as holes are
placed in a bone. Osteotomy guide 250 includes flat insert 254 with
a generally thin smooth slot space 256. Insert 254 fits into slot
252 that accommodates the drill guide. With insert 254 in osteotomy
slot 252, a surgeon may use either a saggital saw or a thin
osteotome to create or complete an osteotomy.
[0068] FIG. 10 shows insert 254 disposed within slot 252 of
osteotomy guide 250. FIGS. 9 and 10 illustrate thumbscrews 258 that
may be placed into thumbscrew holes 260 of osteotomy guide 250 to
secure osteotomy guide 250 to the fixator 10. FIG. 11 shows
osteotomy guide 250 attached to fixator 10 by thumbscrews 258.
[0069] Although the present invention and its advantages have been
described in detail it should be understood that various changes,
substitutions, and alterations can be made hereto without departing
from the spirit and scope of the invention as defined by the
following claims.
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