US20060142767A1

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Info

Publication number: US20060142767A1
Application number: US11/024,208
Authority: US
Inventors: Daniel Green; Joseph Molino
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-12-27
Filing date: 2004-12-27
Publication date: 2006-06-29
Also published as: US20100004652A1; US8029507B2

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.

Description

BACKGROUND OF THE INVENTION

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.

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.

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.

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.

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.

Another less invasive procedure is known as hemiepiphyseal stapling. The principal steps of this procedure are as shown inFIGS. 1A-1C. For a genu valgus condition, astaple10 is driven into thelateral side15 of thedistal femur12 about the distal femur physis orgrowth plate18. For a genu varus condition, thestaple10 would alternatively be driven into themedial side22 of thedistal femur12 about thegrowth plate18. Other locations for stapling may include the lateral or medial sides of theproximal tibia24. Thestaple10 has two

prongs

14,16 that straddle the distalfemur growth plate18 and across member20 that extends between the

prongs

14,16. Typically, the prongs are oriented perpendicular to thecross member20. Depending on the age and amount of angular deformity, more than one staple may be used. Ideally, thestaple10 with its

prongs

14,16 promote asymmetric growth on the medial side of thegrowth plate18, while inhibiting growth on the lateral side of thegrowth plate18 as shown bygrowth lines26 andgrowth distance28 inFIG. 1B, to thereby reduce the initial tibial-femoral angle a, (FIG. 1A) to a more acceptable angle a₂(FIG. 1B)

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 thestaple10 must have prongs14,16 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 ⅓ distance into the bone, than approximately ⅓ 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.

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 thecross member20 if thestaple10 is inserted too far into the bone.

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

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.

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

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:

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;

FIG. 1B is a view similar toFIG. 1A showing limited asymmetric growth of the distal femoral growth plate resulted from use of a staple;

FIG. 1C is a sectional view of the prior art hemiepiphyseal stapling technique;

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;

FIG. 2B is a is a view similar toFIG. 2A showing asymmetric growth of the distal femoral growth plate;

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;

FIG. 3 is an enlarged elevational view similar toFIG. 2A showing various phases of the asymmetric growth and positions of the orthopedic device corresponding to such;

FIG. 4 is a front perspective view of the orthopedic device in accordance with the present invention;

FIG. 5 is a rear perspective view of the orthopedic device;

FIG. 6 is a rear elevational view of the orthopedic device;

FIG. 7 is a side elevational view of the orthopedic device;

FIG. 8 is a top plan view of the orthopedic device;

FIG. 9 is a sectional view of the orthopedic device taken along section line9-9 ofFIG. 6;

FIG. 10 is a sectional view of the orthopedic device positioned on the distal femur and aligned with the distal femoral growth plate;

FIG. 11 is a is a rear elevational view of an orthopedic device in accordance with a further embodiment of the invention;

FIG. 12 is a side elevational view of the orthopedic device ofFIG. 11;

FIG. 13 is a top plan view of the orthopedic device ofFIG. 11; and

FIG. 14 is a rear elevational view of an orthopedic device in accordance with yet a further embodiment of the invention.

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

Referring to the drawings and toFIGS. 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 uniqueorthopedic device50 onto thelateral side15 of thedistal femur12 about the distal femur physis orgrowth plate18. For a genu varus condition, theorthopedic device50 would alternatively be mounted onto themedial side22 of thedistal femur12 about thegrowth plate18. Other locations that may be suitable for installing theorthopedic device50 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.

With further reference toFIGS. 4-10, theorthopedic device50 includes a first substantiallyrigid hinge plate52 pivotally connected to a second substantiallyrigid hinge plate54 by means of ahinge pin56. The

plates

52,54 are preferably generally rectangular in shape, although other shapes, such as triangular, circular, and so on are also contemplated.

Thefirst hinge plate52 is formed with abone mounting portion58, a rampedportion60 extending at an angle from the bone mounting portion, and ahinge portion62 extending from the ramped portion. Thebone mounting portion58 includes aninner surface64 that faces the bone when mounted to a patient and anouter surface66 that faces away from the bone. Achannel68 is formed in theinner surface64 and extends substantially from adistal end70 of thefirst hinge plate52 to the rampedportion60. As best shown inFIG. 10, to facilitate positioning and alignment of thefirst hinge plate52, the shape of thechannel68 is preferably at least partially complementary to the shape of the bone portion to which thehinge plate52 will be mounted. Accordingly, it will be understood that thechannel68 can take on a variety of different shapes. It will be further understood that, if necessary, thechannel68 may be eliminated. A chamferedopening72 extends through thefirst hinge plate52 from theouter surface66 to thechannel68. Theopening72 is preferably centrally located in thebone mounting portion58 and is adapted to receive a fastener74 (see for exampleFIGS. 2A-2C) for securing thefirst hinge plate52 to the respective bone structure.

Thehinge portion62 includes a bore (not shown) that extends therethrough for accommodating thehinge pin56. Preferably, the inner diameter of the bore is greater than an outer diameter of thehinge pin56, so that thefirst hinge plate52 can rotate freely about the hinge pin. The rampedportion60—hingeportion62 interface is in the form of a single energizing element extending outwardly from theplate52, so that two

shoulders

65,67 are formed on both sides thereof.

Thesecond hinge plate54 has abone mounting portion78, a rampedportion80 extending at an angle from thebone mounting portion78, and abifurcated hinge portion82 extending from the ramped portion. Thebone mounting portion78 includes aninner surface84 that faces the respective bone structure, when mounted to a patient, and anouter surface86 that faces away from the bone. Achannel88 is formed in theinner surface84 and extends substantially from adistal end90 of thesecond hinge plate54 to the rampedportion80. As best illustrated inFIG. 10, to facilitate positioning and alignment of thesecond hinge plate54, the shape of thechannel88 is preferably at least partially complementary to the shape of the respective bone portion. Accordingly, it will be understood that thechannel88 can take on a variety of different shapes, and may be different in configuration from the shape of thechannel68 of thefirst hinge plate52. It will be further understood that, if it is necessary, thechannel88 may be eliminated. A chamferedopening92 extends through thesecond hinge plate82 from theouter surface86 to thechannel88. Theopening92 is preferably centrally located in thebone mounting portion78 and is adapted to receive a fastener74 (see for exampleFIGS. 2A-2C) for securing thesecond hinge plate54 to the bone.

Thebifurcated hinge portion82 includes spaced

arms

94,96 and a bore (not shown) extending through each arm for accommodating thehinge pin56. Preferably, the inner diameter of the bore is less than or equal to an outer diameter of thehinge pin56. In this manner thehinge pin56 can be press-fit into the spaced

arms

94,96 and held against rotation with respect to thesecond hinge plate54. The

arms

94,96 are sufficiently spaced to movably receive the singleelement hinge portion62 of thefirst hinge plate52 therebetween. In the assembled condition, the ramped

portions

60,80 and hinge

portions

62,82 of the first and second hinge plates form anoperational recess69 extending inwardly from the planes of the

inner surfaces

64,84.

As shown inFIG. 5, afirst stop surface98 is formed on thehinge portion62 of thefirst hinge plate52 and a correspondingsecond stop surface100 is formed on thehinge portion62 between the

arms

94,96 of thesecond hinge plate54. The first and second stop surfaces98,100 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 theorthopedic device50 will no longer pivot and therefore can be removed from the patient.

As shown inFIGS. 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 theorthopedic device50 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.

In accordance with an exemplary embodiment of the invention, theorthopedic device50 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 thedistal end70 to thedistal end90. However, it will be understood that these dimensions are given by way of example only and that theorthopedic device50 can greatly vary in size and shape.

With particular reference toFIGS. 2A-2C,3 and10, a method of correcting the angular bone deformity, such as the genu varus condition, includes exposing thegrowth plate18 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 theorthopedic device50. Once the soft tissues and muscles have been retracted, the underlying periosteum (dense fibrous membrane covering the surface of bones) is opened. Theorthopedic device50 is then placed on thelateral side15 of thedistal femur12 such that thefirst hinge plate52 abuts a firstcondyle bone portion55, thesecond hinge plate54 abuts a secondcondyle bone portion57, so that theoperational recess69 and thehinge pin56 or pivot joint are in alignment with thegrowth plate18 which is now positioned between the first and second bone portions. Optimum alignment of the pivot joint and theoperational recess69 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 theorthopedic device50 can be mounted with greater control and precision. The precise positioning of theoperational recess69 including the pivot joint at thegrowth plate18 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 theorthopedic device50 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

Once theorthopedic device50 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,fasteners70, preferably in the form of bone screws with ball-shapedheads102, 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 theorthopedic device50.

Once theorthopedic device50 is properly placed and securely mounted to the bone, it can be seen that theoperational recess69 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 thegrowth plate18 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 theorthopedic device50 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, thecross member20 that connects the

prongs

14,16 of the prior art staple has a tendency to contact and damage the growth plate (seeFIGS. 1A-1C).

In use, as shown inFIGS. 2A, 2B and3, the installedorthopedic device50 promotes asymmetric growth on the medial side of thegrowth plate18 while inhibiting growth on the lateral side thereof as shown bygrowth lines110 andgrowth distance112 to thereby reduce the initial tibial-femoral angle a₁(FIG. 2A) to a more acceptable angle a₂(FIG. 2B). Since theorthopedic device50 pivots at the lateral side of thegrowth plate18, one or both of thefasteners74 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 and54C, thefastener74 movement is illustrated by

lines

74A,74B and74C and the increasing distance between the distal ends of the fasteners is represented by lengths L1, L2 and L3. Movement of thesecond hinge plate54 and thefastener102 associated therewith corresponds to bone growth or

movement lines

12A,12B and12C inFIG. 3. In view of the ramped

portions

60,80 andoperational recess69 formed there between, the pivotal joint is spaced from but positioned precisely at thegrowth plate18. In this manner, the growth of the bone structure at the lateral side of thegrowth plate18 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 theorthopedic device50 at the desired location, thus minimizing potential damage to the growth plate while maximizing the mounting strength of theorthopedic device50 to the bone structure.

Referring now toFIGS. 11-13, anorthopedic device120 in accordance with a further embodiment of the invention is illustrated. Theorthopedic device120 is similar to theorthopedic device50 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, theorthopedic device120 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.

Referring now toFIG. 14 wherein anorthopedic device130 in accordance with yet a further embodiment of the invention is illustrated. Theorthopedic device130 is similar to theorthopedic device50 previously described, with the exception that the chamfered opening in each

hinge plate

52 and54 is replaced with an

elongate slot

132 and134, respectively. The

elongate slots

132 and134 preferably extend in the direction of their associated

channels

68 and88, 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 theorthopedic device130 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 thegrowth plate18, one or more of thefasteners74 need simply be loosened and theorthopedic device130 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.

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.

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 toclaim 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 toclaim 2, wherein each hinge plate further comprises a ramp portion that extends at an angle from the mounting portion.

4. An orthopedic device according toclaim 3, wherein each hinge plate further comprises a hinge portion that extends from the ramp portion.

5. An orthopedic device according toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 8, wherein the channel extends between a distal end of each hinge plate and the respective ramped portion.

10. An orthopedic device according toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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 toclaim 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.