U.S. patent application number 11/024208 was filed with the patent office on 2006-06-29 for orthopedic device and method for correcting angular bone deformity.
Invention is credited to Daniel W. Green, Joseph L. Molino.
Application Number | 20060142767 11/024208 |
Document ID | / |
Family ID | 36612774 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060142767 |
Kind Code |
A1 |
Green; Daniel W. ; et
al. |
June 29, 2006 |
Orthopedic device and method for correcting angular bone
deformity
Abstract
An orthopedic device and method for correcting angular
deformation of a bone structure having a growth plate. The device
includes first and second hinge members connected together at a
hinge joint. The device is adapted for mounting the orthopedic
device to the bone structure with the pivot joint positioned over
the growth plate. Alignment of the pivot joint with the growth
plate promotes asymmetric growth of the growth plate to thereby
correct the angular deformation.
Inventors: |
Green; Daniel W.; (Bronx,
NY) ; Molino; Joseph L.; (Cottage, NY) |
Correspondence
Address: |
SILBER & FRIDMAN
1037 ROUTE 46 EAST
SUITE 207
CLIFTON
NJ
07013
US
|
Family ID: |
36612774 |
Appl. No.: |
11/024208 |
Filed: |
December 27, 2004 |
Current U.S.
Class: |
606/71 ;
606/281 |
Current CPC
Class: |
A61B 17/8004 20130101;
A61B 17/80 20130101 |
Class at
Publication: |
606/069 |
International
Class: |
A61F 2/30 20060101
A61F002/30 |
Claims
1. An orthopedic device for correcting angular deformation of a
bone structure having a first bone portion separated from a second
bone portion by a growth plate, the device comprising: a first
hinge member adapted for connection to the first bone portion; a
second hinge member pivotally connected to the first hinge member
at a pivot joint and adapted for connection to the second bone
portion; wherein alignment of the pivot joint with the growth plate
promotes asymmetric growth of the growth plate to thereby correct
the angular deformation.
2. An orthopedic device according to claim 1, wherein the first and
second hinge members comprise first and second hinge plates,
respectively, each hinge plate comprising a mounting portion with a
first surface adapted to face one of the bone portions.
3. An orthopedic device according to claim 2, wherein each hinge
plate further comprises a ramp portion that extends at an angle
from the mounting portion.
4. An orthopedic device according to claim 3, wherein each hinge
plate further comprises a hinge portion that extends from the ramp
portion.
5. An orthopedic device according to claim 4, wherein the hinge
portion is offset from the first surface to substantially prevent
contact between the orthopedic device and the growth plate.
6. An orthopedic device according to claim 5, and further
comprising a hinge pin extending through the hinge portion of each
hinge plate to thereby pivotally connect the hinge plates together
at the pivot joint.
7. An orthopedic device according to claim 6, wherein the ramped
portions and the hinge portions of the first and second hinge
members form an operational recess extending inwardly from surfaces
of the hinge members connected to the respective bone portions.
8. An orthopedic device according to claim 6, wherein the first
surface of each hinge plate comprises a channel adapted for
contacting one of the bone portions.
9. An orthopedic device according to claim 8, wherein the channel
extends between a distal end of each hinge plate and the respective
ramped portion.
10. An orthopedic device according to claim 9, and further
comprising at least one opening extending through each of the hinge
plates, the at least one opening being aligned with the channel and
adapted to receive a fastener for mounting the first and second
hinge plates to the respective bone portions.
11. An orthopedic device according to claim 10, wherein the at
least one opening comprises an elongated slot adopted for adjusting
position of the pivot joint at the respective bone portions.
12. An orthopedic device according to claim 9, wherein the first
and second hinge plates include stop surfaces for limiting relative
angular rotation between the hinge plates.
13. An orthopedic device according to claim 2, wherein the first
surface of each hinge plate comprises a channel adapted for
contacting one of the bone portions.
14. An orthopedic device according to claim 2, wherein the pivot
joint is offset from the first surface to substantially prevent
contact between the orthopedic device and the growth plate.
15. An orthopedic device according to claim 1, and further
comprising at least one opening extending through each of the hinge
members, the at least one opening being adapted to receive a
fastener for mounting the first and second hinge members to the
respective bone portions.
16. An orthopedic device according to claim 15, wherein the at
least one opening comprises an elongated slot for adjusting
position of the pivot joint relative to the growth plate.
17. A method of correcting angular deformation of a bone structure
having a first bone portion separated from a second bone portion by
a growth plate by means of an orthopedic device having a first
hinge member pivotally connected to a second hinge member at a
pivot joint, the method comprising: aligning the pivot joint with
the growth plate; and mounting the first and second hinge members
to the first and second bone portions, respectively; wherein the
alignment of the pivot joint with the growth plate promotes
asymmetric growth of the growth plate to thereby correct the
angular deformation.
18. A method according to claim 17, wherein the mounting step
comprises spacing the pivot joint from the growth plate to thereby
prevent growth plate damage by contact with the pivot joint.
19. A method according to claim 17, wherein the mounting step
comprises driving at least one fastening member through at least
one of the hinge members and into one of the bone portions.
20. A method according to claim 19, wherein the at least one
fastening member is a bone screw head and wherein the driving step
comprises orienting the bone screw in a direction parallel to or
away from the growth plate.
21. A method according to claim 17, and further comprising limiting
relative angular rotation between the first and second hinge
members when the angular deformation has been corrected.
22. A method according to claim 17, and further comprising
providing at least one slot in each of the hinge members and
further wherein the mounting step comprises driving at least one
bone screw through at least one of the slots and into one of the
bone portions.
23. A method according to claim 22, wherein the aligning step
comprises sliding the orthopedic device with respect to the at
least one bone screw until the pivot joint is aligned with the
growth plate.
24. A method according to claim 23, wherein the at least one bone
screw comprises a rounded head and wherein the driving step
comprises orienting the bone screw in a direction parallel to or
away from the growth plate to thereby secure the orthopedic device
to the bone structure.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to correcting angular bone
deformities, and more particularly to an orthopedic device and
method for correcting angular deformities of the lower extremities,
such as genu varus and genu valgus conditions.
[0002] Angular bone deformities of the lower extremities are
typically characterized by abnormal angulations of the lower leg in
relation to the thigh. For example, genu varum is characterized by
an abnormal outward bowing of the leg resulting in bowlegs, while
genu valgum is characterized by an inward bowing of the leg and is
commonly referred to as knock-knees. Under normal conditions, the
femur and tibia meet at a tibial-femoral angle of approximately
5-12 degrees of valgus. A greater angle results in a genu valgus
condition while a lesser angle results in a genu varum condition.
Either of these conditions in one or both legs may result in
improper load distribution on the knee joint, causing swelling,
knee pain, loss of stability, subluxation, increased joint
arthritis, and other conditions that restrict one's lifestyle.
[0003] Angular bone deformities in young children can be caused by
the following conditions, which are by no means exhaustive: Blount
disease, Cerebral Palsy, Larsen's Syndrome, dysplastic disorders,
rickets, chronic inflammatory arthritis, neuromuscular causes of
hypotonia and fractures.
[0004] Various procedures have been developed for treating genu
varum and genu valgum in young patients, such as children and
adolescents that have not reached full growth. One such procedure
is known as cuneiform or wedge osteotomy in which a wedge-shaped
section of bone is surgically removed to allow realignment of the
bone. The wedge cut made by the surgeon should not completely sever
the tibia so that a bridge of residual bone is intact to
effectually serve as a hinge for reduction of the wedge-shaped gap
that remains following removal of the bone wedge. The depth of the
wedge is critical in that if the wedge is too shallow, thus
rendering the bridge too wide, the resulting wide fulcrum results
in over stressing of the medial cortex during wedge compression,
causing fracture of the bone bridge. If the wedge is too deep (the
residual bone bridge is too narrow) the residual bone bridge, if
not completely severed, may lack sufficient strength to provide
medial stability to the reduced osteotomy. Reduction of the
wedge-shaped gap allows realignment of the bone, and correction of
the loading patterns of the leg. Bone plates are then installed to
secure the reshaped bone, at least through the healing process.
Although this technique has proven widely successful for adults
that have no other recourse or for severe deformities that cannot
be corrected by any other means, it is preferable to use less
invasive procedures for children and adolescents that have not
reached their full stature.
[0005] One less invasive procedure for treating the valgus and
varus conditions of children or adolescents still in the growth
stage includes damaging or destroying one half of the physis or
growth plate of the distal femur or proximal tibia by scraping or
cutting, with the premise that the undamaged portion will continue
to grow in an asymmetric manner to affect the angulation of the
lower extremity. However, this technique involves destruction of
one half of the growth plate and therefore not a viable option for
all patients.
[0006] Another less invasive procedure is known as hemiepiphyseal
stapling. The principal steps of this procedure are as shown in
FIGS. 1A-1C. For a genu valgus condition, a staple 10 is driven
into the lateral side 15 of the distal femur 12 about the distal
femur physis or growth plate 18. For a genu varus condition, the
staple 10 would alternatively be driven into the medial side 22 of
the distal femur 12 about the growth plate 18. Other locations for
stapling may include the lateral or medial sides of the proximal
tibia 24. The staple 10 has two prongs 14, 16 that straddle the
distal femur growth plate 18 and a cross member 20 that extends
between the prongs 14, 16. Typically, the prongs are oriented
perpendicular to the cross member 20. Depending on the age and
amount of angular deformity, more than one staple may be used.
Ideally, the staple 10 with its prongs 14, 16 promote asymmetric
growth on the medial side of the growth plate 18, while inhibiting
growth on the lateral side of the growth plate 18 as shown by
growth lines 26 and growth distance 28 in FIG. 1B, to thereby
reduce the initial tibial-femoral angle a, (FIG. 1A) to a more
acceptable angle a.sub.2 (FIG. 1B)
[0007] Although hemiepiphyseal stapling is, in some instances,
advantageous over other techniques, it suffers from numerous
drawbacks. For optimal bone angle correction, growth of the physis
should be inhibited on one and unrestricted on the opposite side.
However, since the staple 10 must have prongs 14, 16 of sufficient
length to ensure firm anchorage into the distal femur, more of the
physis may be restricted from growth than desired, leading to less
bone angle correction. By way of example, if the prongs extend
approximately 1/3 distance into the bone, than approximately 1/3 of
the physis will be restricted from growth due to prong resistance.
If the stapling procedure is performed toward the end of the growth
cycle (13-15 years of age for girls and 16-17 years of age for
boys) and does not produce the desired results, then more invasive
procedures, such as wedge osteotomy as described above, may have to
be performed.
[0008] In addition, the staple itself must be inserted with extreme
caution, and always in conjunction with radiography to ensure that
the ends of the prongs are sufficiently spaced from the growth
plate to prevent its damage. Moreover, the dense fibrous tissue
(known as the perichrondial ring of LaCroix) that surrounds,
anchors and supports the physis during the growth phase may become
permanently damaged by the cross member 20 if the staple 10 is
inserted too far into the bone.
[0009] It would therefore be desirous to provide an orthopedic
implant and method for correcting angular bone deformity which
minimizes or eliminates the deficiencies of the prior art devices
and techniques. It would be further desirous to provide the
orthopedic implant and method which promotes asymmetric growth of
the growth plate without damaging fibrous tissue by means of a
pivotal motion of one part of the device relative to another.
BRIEF SUMMARY OF THE INVENTION
[0010] One aspect of the present invention provides an orthopedic
device for correcting angular deformation of a bone structure
having a first bone portion separated from a second bone portion by
a growth plate. The orthopedic device includes first and second
hinge members that are pivotally connected together at a pivot
joint. The first hinge member is adapted for connection to the
first bone portion and the second hinge member is adapted for
connection to the second bone portion. Alignment of the pivot joint
with the growth plate promotes asymmetric growth of the growth
plate to thereby correct the angular deformation.
[0011] Another aspect of the present invention provides a method of
correcting angular deformation of a bone structure having a first
bone portion separated from a second bone portion by a growth
plate. The method comprises providing an orthopedic device having a
first hinge member pivotally connected to a second hinge member at
a pivot joint, aligning the pivot joint with the growth plate, and
mounting the first and second hinge members to the first and second
bone portions, respectively. In this manner, alignment of the pivot
joint with the growth plate promotes asymmetric growth of the
growth plate to thereby correct the angular deformation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The foregoing summary as well as the following detailed
description of the preferred embodiments of the present invention
will be best understood when considered in conjunction with the
accompanying drawings, wherein like designations denote like
elements throughout the drawings, and wherein:
[0013] FIG. 1A is a front elevational view of a distal femur and
proximal tibia and fibula with their respective growth plates and a
prior art hemiepiphyseal stapling technique for encouraging
asymmetric growth of the distal femoral growth plate;
[0014] FIG. 1B is a view similar to FIG. 1A showing limited
asymmetric growth of the distal femoral growth plate resulted from
use of a staple;
[0015] FIG. 1C is a sectional view of the prior art hemiepiphyseal
stapling technique;
[0016] FIG. 2A is a front elevational view of a distal femur and
proximal tibia and fibula with their respective growth plates and
an implanted orthopedic device in accordance with the present
invention for encouraging asymmetric growth of the distal femoral
growth plate;
[0017] FIG. 2B is a is a view similar to FIG. 2A showing asymmetric
growth of the distal femoral growth plate;
[0018] FIG. 2C is a is a sectional view of the distal femoral
growth plate and surrounding bone with the implanted orthopedic
device in accordance with the present invention;
[0019] FIG. 3 is an enlarged elevational view similar to FIG. 2A
showing various phases of the asymmetric growth and positions of
the orthopedic device corresponding to such;
[0020] FIG. 4 is a front perspective view of the orthopedic device
in accordance with the present invention;
[0021] FIG. 5 is a rear perspective view of the orthopedic
device;
[0022] FIG. 6 is a rear elevational view of the orthopedic
device;
[0023] FIG. 7 is a side elevational view of the orthopedic
device;
[0024] FIG. 8 is a top plan view of the orthopedic device;
[0025] FIG. 9 is a sectional view of the orthopedic device taken
along section line 9-9 of FIG. 6;
[0026] FIG. 10 is a sectional view of the orthopedic device
positioned on the distal femur and aligned with the distal femoral
growth plate;
[0027] FIG. 11 is a is a rear elevational view of an orthopedic
device in accordance with a further embodiment of the
invention;
[0028] FIG. 12 is a side elevational view of the orthopedic device
of FIG. 11;
[0029] FIG. 13 is a top plan view of the orthopedic device of FIG.
11; and
[0030] FIG. 14 is a rear elevational view of an orthopedic device
in accordance with yet a further embodiment of the invention.
[0031] It is noted that the drawings are intended to depict only
typical embodiments of the invention and therefore should not be
considered as limiting the scope thereof. It is further noted that
the drawings are not necessarily to scale. The invention will now
be described in greater detail with reference to the accompanying
drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Referring to the drawings and to FIGS. 2A-2C in particular,
wherein a procedure for correcting a genu valgus condition in
accordance with an exemplary embodiment of the present invention is
illustrated. The procedure includes installing a unique orthopedic
device 50 onto the lateral side 15 of the distal femur 12 about the
distal femur physis or growth plate 18. For a genu varus condition,
the orthopedic device 50 would alternatively be mounted onto the
medial side 22 of the distal femur 12 about the growth plate 18.
Other locations that may be suitable for installing the orthopedic
device 50 may include, without limitation, the growth plate region
of proximal tibia, distal tibia, proximal femur, as well as
locations on the humerous, ulna and/or radius and spinal
formation.
[0033] With further reference to FIGS. 4-10, the orthopedic device
50 includes a first substantially rigid hinge plate 52 pivotally
connected to a second substantially rigid hinge plate 54 by means
of a hinge pin 56. The plates 52, 54 are preferably generally
rectangular in shape, although other shapes, such as triangular,
circular, and so on are also contemplated.
[0034] The first hinge plate 52 is formed with a bone mounting
portion 58, a ramped portion 60 extending at an angle from the bone
mounting portion, and a hinge portion 62 extending from the ramped
portion. The bone mounting portion 58 includes an inner surface 64
that faces the bone when mounted to a patient and an outer surface
66 that faces away from the bone. A channel 68 is formed in the
inner surface 64 and extends substantially from a distal end 70 of
the first hinge plate 52 to the ramped portion 60. As best shown in
FIG. 10, to facilitate positioning and alignment of the first hinge
plate 52, the shape of the channel 68 is preferably at least
partially complementary to the shape of the bone portion to which
the hinge plate 52 will be mounted. Accordingly, it will be
understood that the channel 68 can take on a variety of different
shapes. It will be further understood that, if necessary, the
channel 68 may be eliminated. A chamfered opening 72 extends
through the first hinge plate 52 from the outer surface 66 to the
channel 68. The opening 72 is preferably centrally located in the
bone mounting portion 58 and is adapted to receive a fastener 74
(see for example FIGS. 2A-2C) for securing the first hinge plate 52
to the respective bone structure.
[0035] The hinge portion 62 includes a bore (not shown) that
extends therethrough for accommodating the hinge pin 56.
Preferably, the inner diameter of the bore is greater than an outer
diameter of the hinge pin 56, so that the first hinge plate 52 can
rotate freely about the hinge pin. The ramped portion 60--hinge
portion 62 interface is in the form of a single energizing element
extending outwardly from the plate 52, so that two shoulders 65, 67
are formed on both sides thereof.
[0036] The second hinge plate 54 has a bone mounting portion 78, a
ramped portion 80 extending at an angle from the bone mounting
portion 78, and a bifurcated hinge portion 82 extending from the
ramped portion. The bone mounting portion 78 includes an inner
surface 84 that faces the respective bone structure, when mounted
to a patient, and an outer surface 86 that faces away from the
bone. A channel 88 is formed in the inner surface 84 and extends
substantially from a distal end 90 of the second hinge plate 54 to
the ramped portion 80. As best illustrated in FIG. 10, to
facilitate positioning and alignment of the second hinge plate 54,
the shape of the channel 88 is preferably at least partially
complementary to the shape of the respective bone portion.
Accordingly, it will be understood that the channel 88 can take on
a variety of different shapes, and may be different in
configuration from the shape of the channel 68 of the first hinge
plate 52. It will be further understood that, if it is necessary,
the channel 88 may be eliminated. A chamfered opening 92 extends
through the second hinge plate 82 from the outer surface 86 to the
channel 88. The opening 92 is preferably centrally located in the
bone mounting portion 78 and is adapted to receive a fastener 74
(see for example FIGS. 2A-2C) for securing the second hinge plate
54 to the bone.
[0037] The bifurcated hinge portion 82 includes spaced arms 94, 96
and a bore (not shown) extending through each arm for accommodating
the hinge pin 56. Preferably, the inner diameter of the bore is
less than or equal to an outer diameter of the hinge pin 56. In
this manner the hinge pin 56 can be press-fit into the spaced arms
94, 96 and held against rotation with respect to the second hinge
plate 54. The arms 94, 96 are sufficiently spaced to movably
receive the single element hinge portion 62 of the first hinge
plate 52 therebetween. In the assembled condition, the ramped
portions 60, 80 and hinge portions 62, 82 of the first and second
hinge plates form an operational recess 69 extending inwardly from
the planes of the inner surfaces 64, 84.
[0038] As shown in FIG. 5, a first stop surface 98 is formed on the
hinge portion 62 of the first hinge plate 52 and a corresponding
second stop surface 100 is formed on the hinge portion 62 between
the arms 94, 96 of the second hinge plate 54. The first and second
stop surfaces 98, 100 are arranged to engage and stop relative
rotating movement between the hinge plates when a particular
rotation angle has been reached. By way of example, it may be
desirous to limit the angular correction of the bone deformity to
five degrees for one patient, 20 degrees for another patient, 30
degrees for yet another and 45 degrees for still another patient.
Thus, the stop surfaces may be dimensioned or otherwise formed as
needed to accommodate a particular desired rotational limit. This
feature is especially advantageous since overcorrection of the bone
deformity is discouraged. Once the required angular bone deformity
correction has been achieved and the desired bone angle has been
reached, the hinge plates 52, 54 of the orthopedic device 50 will
no longer pivot and therefore can be removed from the patient.
[0039] As shown in FIGS. 4-10, all corners and ends of the first
and second hinge plates are rounded to eliminate sharp edges or
protrusions that may otherwise damage surrounding tissue when the
orthopedic device 50 is installed in a patient. Preferably, the
first and second hinge plates, as well as the hinge pin, are
constructed of biocompatible materials, such as surgical stainless
steel, titanium or combinations thereof, as well as other materials
including metal, ceramic, and/or plastic.
[0040] In accordance with an exemplary embodiment of the invention,
the orthopedic device 50 can be constructed with a very low profile
with a plate thickness of about 2-3 mm and an overall length of
about 1.8 cm from the distal end 70 to the distal end 90. However,
it will be understood that these dimensions are given by way of
example only and that the orthopedic device 50 can greatly vary in
size and shape.
[0041] With particular reference to FIGS. 2A-2C, 3 and 10, a method
of correcting the angular bone deformity, such as the genu varus
condition, includes exposing the growth plate 18 and a portion of
the distal femur surrounding the growth plate by gaining access to
and retracting the overlying soft tissues and muscles. These areas
do not have any significant impediments to placement of the
orthopedic device 50. Once the soft tissues and muscles have been
retracted, the underlying periosteum (dense fibrous membrane
covering the surface of bones) is opened. The orthopedic device 50
is then placed on the lateral side 15 of the distal femur 12 such
that the first hinge plate 52 abuts a first condyle bone portion
55, the second hinge plate 54 abuts a second condyle bone portion
57, so that the operational recess 69 and the hinge pin 56 or pivot
joint are in alignment with the growth plate 18 which is now
positioned between the first and second bone portions. Optimum
alignment of the pivot joint and the operational recess 69 with the
respective portions of the bone structure can be confirmed by
direct vision as well as inter-operative radiographs. The rigidity
of the hinge plates ensures that the orthopedic device 50 can be
mounted with greater control and precision. The precise positioning
of the operational recess 69 including the pivot joint at the
growth plate 18 is one of the major advantages of the device of the
invention over the prior art. Depending on the type of angular
deformity to be corrected, it will be understood that the
orthopedic device 50 can be positioned on either the lateral or
medial side of the bone structure and/or at other locations as
previously mentioned, such as the proximal tibia, distal tibia,
proximal femur, as well as locations on the humerous, ulna and/or
radius
[0042] Once the orthopedic device 50 is correctly placed over the
growth plate with the channel 68, 88 of each hinge plate properly
seated on the condyle bone portions of the distal femur, fasteners
70, preferably in the form of bone screws with ball-shaped heads
102, are inserted through the chamfered openings 72, 92 of the
hinge plates 52, 54 and screwed into the bone. The provision of
screws with ball-shaped heads permits the surgeon to individually
and independently orient the screws away from the growth plate and
toward the most solid portion of the bone. This feature is a great
advantage over prior art stapling since placement of the prongs
cannot be individually and independently controlled, and further
since the screws lend to a more secure mounting of the orthopedic
device 50.
[0043] Once the orthopedic device 50 is properly placed and
securely mounted to the bone, it can be seen that the operational
recess 69 including the ramped portions 60, 80 of the hinge plates
50, 52 ensure that no part of the orthopedic device will come in a
substantial contact with the growth plate 18 or the perichrondial
ring of LaCroix that surrounds the growth plate to thereby prevent
growth plate damage. In addition, the channels 68, 88 of the hinge
plates 50, 52 directly engage the bone structure so that very
little gap remains between the orthopedic device 50 and the bone.
These features are advantageous over prior art stapling since in
some instances there tends to be an undesirable substantial gap
between the cross member of staple and the bone. In the
hemiepiphyseal stapling procedure, when surgeons try to reduce the
gap by placing or pushing or hammering the staple deeper into the
bone, the cross member 20 that connects the prongs 14, 16 of the
prior art staple has a tendency to contact and damage the growth
plate (see FIGS. 1A-1C).
[0044] In use, as shown in FIGS. 2A, 2B and 3, the installed
orthopedic device 50 promotes asymmetric growth on the medial side
of the growth plate 18 while inhibiting growth on the lateral side
thereof as shown by growth lines 110 and growth distance 112 to
thereby reduce the initial tibial-femoral angle a.sub.1 (FIG. 2A)
to a more acceptable angle a.sub.2 (FIG. 2B). Since the orthopedic
device 50 pivots at the lateral side of the growth plate 18, one or
both of the fasteners 74 will also rotate with the new asymmetric
bone growth as the angular deformity reduces. The second hinge
plate movement is illustrated by lines 54A, 54B and 54C, the
fastener 74 movement is illustrated by lines 74A, 74B and 74C and
the increasing distance between the distal ends of the fasteners is
represented by lengths L1, L2 and L3. Movement of the second hinge
plate 54 and the fastener 102 associated therewith corresponds to
bone growth or movement lines 12A, 12B and 12C in FIG. 3. In view
of the ramped portions 60, 80 and operational recess 69 formed
there between, the pivotal joint is spaced from but positioned
precisely at the growth plate 18. In this manner, the growth of the
bone structure at the lateral side of the growth plate 18 is
inhibited in the linear or longitudinal direction. However, in view
of the pivotal arrangement, the growth and development of the
growth plate at the same lateral side in the radial direction is
encouraged. Furthermore, since the pivotal joint is spaced from the
bone structure the entire area of the growth plate (to a smaller
degree at the lateral side and to a greater degree at the medial
side) is able to undergo asymmetric or radial growth. This enables
the orthotic device of the invention to provide a greater degree of
angular correction in an easier, quicker and more controlled manner
than in the prior art. In addition, the use of long screws as the
fasteners permits the surgeon to precisely place the orthopedic
device 50 at the desired location, thus minimizing potential damage
to the growth plate while maximizing the mounting strength of the
orthopedic device 50 to the bone structure.
[0045] Referring now to FIGS. 11-13, an orthopedic device 120 in
accordance with a further embodiment of the invention is
illustrated. The orthopedic device 120 is similar to the orthopedic
device 50 previously described, with the exception that each hinge
plate 52, 54 is wider and includes a pair of spaced chamfered
openings 122, 124 for receiving fasteners, such as the bone screws
previously described. In this manner, the orthopedic device 120 may
be more securely mounted to the bone structure. It will be
understood that other shapes as well as more or less openings may
be provided for each hinge plate.
[0046] Referring now to FIG. 14 wherein an orthopedic device 130 in
accordance with yet a further embodiment of the invention is
illustrated. The orthopedic device 130 is similar to the orthopedic
device 50 previously described, with the exception that the
chamfered opening in each hinge plate 52 and 54 is replaced with an
elongate slot 132 and 134, respectively. The elongate slots 132 and
134 preferably extend in the direction of their associated channels
68 and 88, respectively. It should be noted that the slots 132, 134
may be oriented in a direction transverse or perpendicular to the
direction of the channels. The elongate slots 132, 134 are
especially advantageous during positioning of the orthopedic device
130 on the bone structure. When it has been found by direct vision
and/or inter-operative radiograph that the pivot joint is not
properly aligned with the growth plate 18, one or more of the
fasteners 74 need simply be loosened and the orthopedic device 130
repositioned until the pivot joint is properly aligned over the
growth plate. In this manner, very precise alignment can occur
without additional stress or injury to the bone structure.
[0047] It will be appreciated by those skilled in the art that
changes could be made to the embodiments described above without
departing from the broad inventive concept thereof. It will be
understood, therefore, that this invention is not limited to the
particular embodiments disclosed, but is intended to cover
modifications within the spirit and scope of the present invention
as defined by the appended claims.
* * * * *