This invention relates generally to the field of orthopedic splints which correct for toe-in and toe- 5 out, and more particularly to such a device which corrects one foot or both while allowing some freedom of movement for a normal or abnormal foot. Background Art

In general, an __rtftope.di.G foot splint is useful 10 in correcting bone deformities, particularly in child¬ ren, by holding the patient's feet at an appropriate corrective angle. Thus, if a patient's fee are ab¬ normally toed-in, it is recommended that the patient wear a splint for a specified period which will hold 15 the feet in a corrective toed-out position. A common type of prior art device, as disclosed in U.S. Patents Nos. 2,920,620 (Rogers), 4,040,416 (Zentman) , and 4,008,129 (DiGiulio) , includes a pair of shoes mounted on a flat bar. The shoes in these devices are adjust- 20 able on the bar to provide a variety of different toe- in and toe-out angles, but are not otherwise adjustable. Unfortunately, these prior art devices are extremely uncomfortable to the patient as they maintain the feet in almost rigid positions. Even the patent to 25 Zentman which includes a flexible spacer bar to allow a slight amount of verticle movement does little to alleviate this problem. In addition, the patient can¬ not move except by hopping, which is dangerous and perhaps impossible for young children to perform.

30 To overcome this almost total lack of mobility and extreme discomfort, prior art devices have been proposed which do allow some movement as well. For instance, in U.S. Patents No. 2,963,020 (Moran) and No. 4,303,065 (Ericson) , a device is disclosed which 35 comprises a separate member attached to each shoe of the patient which members are connected by parallelo¬ grams links. These linkages are pivotally attached

to each shoe member and this allows movement of the feet both upwards and downwards , and forwards and rear¬ wards. In addition, the length of the linkages is man¬ ually adjustable in the former patent. U.S. Patent No. 3,487,82-9 (Barnett) also discloses parallelogram links connecting shoe engaging members. In this device, the parallelogram links are attached to the shoe en¬ gaging members by ball and socket joints. This device also allows the feet to move forwards and backwards, and upwards and downwards _t as well as allowing the ends of the shoes to tilt upwards or downwards somewhat. In U.S. Patent No. 4,249,523 (Bidwell) , an ad¬ justable orthopedic foot splint to which a pair of shoes is attached is disclosed which maintains a desired angle between the shoes but which otherwise allows virtually full freedom of movement of the shoes.

Disclosed in pending U.S. application Serial No. 339,058 entitled "Adjustable Orthopedic Shoe For A Foot Splint", filed January 13, 1982, is an orthopedic shoe which is preferably used where the toe of the user is required to be adjusted relative to the heel, and where a foot splint is used to adjust the feet of the user. Disclosed in the pending U.S. application Serial No. 343,555 entitled "Orthopedic Foot Splint", filed January 28, 1982, is an adjustable orthopedic foot splint which allows virtually full freedom of movement of the feet except for an undesired movement of one foot of the user in front of or too close to the other foot. This is accomplished by using parallelogram links with a tether attached therebetween. Both of these ap¬ plications are assigned to the assignee of the present application, and are herein incorporated by reference. Disclosure of the Invention

In accordance with the present invention, an orthopedic foot splint is provided for correcting

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bone deformities by holding the foot to be corrected at a corrective angle. The foot splint of the present invention includes a pair of shoe engaging plates and an elongate connecting means interconnecting the shoe engaging plates. A swivel means is pro¬ vided between the connecting means and the shoe engaging plates so that the shoe engaging plates can swivel about a vertical axis. A stop means is provided in the swivel means so that the toe or heel of a respective shoe can only swivel either towards or away from the connecting means from an initial position which is substantially perpendicular to the longitudinal axis of the connnecting means. With such a device, the shoe engaging plate of the foot requiring correction is restricted from move- ment in the undesired direction, for example toe-in. However, by use of the selected stop means, the foot to be corrected is allowed a swivel movement to the toe-out positon. The other foot, which is frequently without a defect and needs no correction, is also allowed some freedom of movement. Where the foot to be corrected is prevented toeing-in, the normal foot is allowed by the swivel means and stop means to swivel to the toe-in position (although toe-out must be pre¬ vented so that toe-in of the other, defective foot, can be prevented) .

In the preferred embodiment of the present in¬ vention, a lock means is further provided to lock the shoe engaging plate in position and prevent swiveling. The connecting means also includes two bars, having a central pivot, a central hinge, and lateral hinges so that desired movements of the feet are not prevented. Preferably, at least one of the bars also is freely extensible so that the longi¬ tudinal length of the connecting means is easily — varied according to the needs of the user. _OMPI - , W1PO

In the other preferred embodiment of the present invention, the connecting means includes at least one pair or parallelogram links. These parallelogram links- include a tether attached at an angle to the links so that pivoting in the horizontal plane beyond a pre¬ determined angle can be prevented. A bar and a pair parallelogram li-nks can be provided together with a central hinge and lateral hinges at each end. The parallelogram links can also be provided with a block means to prevent pivoting beyond a predetermined angle on either side of a horizontal line perpendicular to the longitudinal axis of the shoe engaging plate. Two pairs of parallelogram links can also be used.

The swivel means preferably comprises a circular aperture in the shoe engaging plate and a circular disc rotatably mounted on the aperture. By providing two cutouts adjacent one another on the circular disc, a screw mounted to the shoe engaging plate which extends into the cutouts can be used to appropriately limit the rotation of the circular disc to the length of the cut¬ out and the corresponding orientation of the foot of the user.

Other features, objects, and advantages of the present invention are stated in or apparent from the detailed description of the presently preferred em¬ bodiments of the invention found hereinbelow. Brief Description of the Drawings

Figure 1 is a perspective view of an orthopedic foot splint according to the present invention. Figure 2 is a cross-sectional plan view of the base plate of the swivel depicted in Figure 1.

Figure 3 is a top plan view of the circular disc of the swivel depicted in Figure 1.

Figure 4 is a front plan view of the circular disc depicted in Figure 3.

Figure 5 is a perspective view of an alternative embodiment of an orthopedic foot splint according to the present invention.

Figure 6 is a bottom plan view of the orthopedic foot splint depicted in Figure 5. Figure 7 is a bottom plan view of still another alternative embodiment of an orthopedic foot splint according to the present invention. Modes for Carrying Out the Invention

With reference now to the drawings in which like numerals represent like elements throughout the several views, a presently preferred embodiment of the present invention is depicted in Figure 1 along with a shoe plate 10 to which the shoe of the user is attached. A preferred type of shoe is disclosed in the pending U.S. application Serial No. 339,058 disclosed above entitled "Adjustable Orthopedic Shoe For A Foot Splint", which is herein incorporated by reference. Orthopedic foot splint 12 includes a connecting means 14, a pair of shoe engaging plates 16a and 16b, and a pair swivel means 18a and 18b.

In the preferred embodiment, connecting means 14 includes two bars 20a and 20b which are interconnected by joint 22. Preferably, each bar 20a and 20b is freely extensible in the longitudinal direction. This is easily provided by forming bars 20a and 20b from telescoping sections. Conveniently, a stop is also provided to prevent the telescoping sections from being pulled apart. Joint 22 includes a central hinge means 24 as well as a central pivot means 26 so that two planes of motion are possible with bars

20a and 20b. Thus, bars 20a and 20b can pivot relative to one another about axis 28 which is horizontal and substantially perpendicular to the longitudinal axis of connecting means 14. In addition, bars 20a and 20b can pivot in a horizontal plane relative to one

another around axes 30 which are vertical. The oppo¬ site ends of bars 20a and 20b are connected to a base plate 32a and 32bby lateral hinge means 34a and 34b. In this manner, base plates 32a and 32b can pivot in a vertical plane relative to bars 20a and 20b about axes 36a and 36b, respectively, which are parallel to axis 28.

As shown in greater detail in Figures 2, 3, and 4, swivel means 18b includes a circular aperture 40 located in base plate 32b and a circular disc 42 which is received in circular aperture 40. As shown in Figure 2, circular aperture 40 includes a shoulder recess 44 and a threaded bore 46. As shown in Figures 3 and 4, circular disc.42 includes a lower shoulder 48. When circular disc 42 is inserted in circular aperture 40 of base plate 32b, shoulder 48 engages shoulder recess 44. In this manner, circular disc 42 is rotatably mounted in base plate 32b.

Circular disc 42 also includes two cutout portions o

50 and 52 which are approximately 90 in length around the circumference of circular disc 42. Located be¬ tween cutout portions 50 and 52 is a small notch 54. The end faces of cutout portions 50 and 52 form stops 56 whose function will be disclosed subsequently. Mounted to the top of circular disc 42 is shoe engag- ing plate 16b which has a substantially T-shaped cross section. Referring again to Figure 1, it can be seen that shoe engaging plate 16b is received in a correspondingly shaped slot 58 in shoe plate 10.

A suitable mechanism is then provided to lock shoe plate 10 to shoe engaging plate 16b. Also shown in Figure 1 is a screw 60 which is received in threaded bore 46 of base plate 32b. By adjusting circular disc 42 appropriately, the end of screw 60 can be located in either of cutout portions 50 and 52 or in notch 54. When the end of screw 60 is located in notch 54, circular disc 42 cannot rotate relative to base plate 32b. However, when the end of screw 60 is located in either of

cutout portions 50 and 52 , circular disc 42 can rotate o approximately 90 relative to base plate 32b until the end of screw 60 contacts stops 56. It should be appreciated that shoe plate 10 extends longitudinally beyond both ends of shoe engaging plate 16b so that circular disc 42 is trapped in base plate 32b by shoulder 48 and the bottom of shoe plate 10.

In operation, orthopedic foot splint 12 functions in the following manner. Initially, it must be de- - ^" w-hart _sotϊdl"ti τ_ exis-s -in th-e pa-i-fetrt Baiύ *fche appropriate corrective position of the foot which is desired. For example, where the right foot of the patient is toed-in, it is desired to hold the right foot in a substantially parallel or toed-out position. However, where the- left foot is normal and requires no corrective action, it is desired to provide as much freedom as possible to the left foot. Therefore, cir¬ cular disc 42b is initially adjusted so that the end of screw 60 is located in cutout portion 50. Similarly- the end of the screw in swivel means 18a is located in one of the corresponding cutouts in circular disc 42a. In this manner, the right foot is prevented by the movement of circular disc 42b from moving to the toed-in position (i.e., always maintained in the toed-out position) , and the right foot is allowed free¬ dom of movement in the toed-out position. Similarly, o the other, normal foot is allowed approximately 90 of free movement in either the toed-in or toed-out poistion (preferably, the toed-in position) . By use of orthopedic foot splint 12, an approx¬ imately normal walking movement is allowed while the right foot of the user is maintained in the toed-out position. Thus, during walking, as the right foot is brought forward relative to the left foot, the right foot is maintained in the toed-out position by swivel means 18b even though the right foot can be raised or lowered due to lateral hinge means 34a and 34b and

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central hinge means 24 . The bringing forward of the right foot is allowed by the pivoting of bars 20a and 20b relative to one another due to central pivot means 26 . The separation of the feet of the user is easily varied due to the telescoping parts of bars 20a and 20b so that pressure on the knee and hip from an im¬ proper separation is avoided.

If it is desired to prevent either one of the feet from obtaining a toed-in or a toed-out position , it is also possible to adjust the end of screw 70 so hat the end is received in notch 54 . In this manner , the re¬ spective foot is then maintained between the toed-out and toed-in position. Obviously, both feet could also be maintained in either the toed-in or toed-out position if necessary .

Besides having a toed-in or toed-out condition , it is frequently found that the patient in addition has difficulty with one foot rotating in an inward direction in front of the other foot while walking . While orthopedic foot splint 12 does not correct for this condition, orthopedic foot splint 112 does correct for this condition . Orthopedic foot splint 112 is somewhat similar to the orthopedic foot splint disclosed in the pending U .S . application Serial No . 343 , 555 referred to above entitled "Orthopedic Foot Splint" , which application is herein incorporated by reference. In this embodiment , orthopedic foot splint 112 includes a connecting means 114 comprised of a bar 120 and a pair of parallelogram links 121a and 121b . Orthopedic foot splint 112 also includes swivel means 118a and 118b and shoe engaging plates such as 116b . Shoe plates 110 are also shown .

In this ertiboidrrent, bar 120 is attached to parallelogram links 121a and 121b by a central hinge means 124. In addition, parallelogram links 121a and 121b are attached to central hinge means 124 by central pivot means 126. A lateral hinge means 134 is also provided to attach parallelogram links 121a and 121b to base plate 132. Attached between links 121a and 121b at an angle thereto is a tether 138 . Tether 138 pre- vents links 121a and 121b from pivoting beyond

a predetermined angle. As depicted, tether 138 pre¬ vents links 121a and 121b from pivoting forward, but allows pivoting rearward.

In operation, orthopedic foot splint 112 functions in a manner similar to orthopedic foot splint 12. The feet of the user are restrained in a similar manner, and similar freedoms of movement are allowed. However, orthopedic foot splint 112 prevents one foot (the right foot) from moving in front of the other foot. During walking, as the right foot is moved forward, parallelogram links 121a and 121b pivot about central pivot means 126 and a lateral pivot means 135. However, as the right foot is brought laterally adjacent to the left foot, tether 138 prevents parallelogram links 121a and 121b from pivoting in a horizontal plane any further. There¬ fore, the right foot cannot pivot any further forward as well and is prevented from crossing in front of the left foot. The left foot is then free to move forward in a relatively normal manner. In order to prevent the left foot from moving too far forward, blocks 139 are located on parallelogram link 121a. It should be noted that where orthopedic foot splint 112 is being used to prevent toe-in of the right foot, swivel means 118 of the left foot must be adjusted so that either toe-in (preferably) or no rotating movement is allowed. .If swivel means 118 of the left foot is adjusted so that toe-out is provided, this would allow the right foot to crossover towards the left foot during forward movement of the right foot. Depicted in Figure 7 as a modified orthopedic foot splint 212 which is similar to orthopedic foot splint 112. In this emboidment, two pairs of parallelogram links 221a, 221b, 221c, and 221d are provided. Con- necting the two pairs of parallelogram links are a central hinge means 224, and a central pivot means 226. At the opposite ends of the two pairs of paral¬ lelogram links are lateral hinge means 234 and lateral

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pivot means 235. Orthopedic foot splint 212 is pro¬ vided with suitable swivel means 218 and shoe plates 210. Connecting one pair of parallelogram links, such as parallelogram links 221a and 221b,is a tether 238.

The operation of foot splint 212 is similar to the operation of foot splint 112. However, with foot splint 212, only the swivel means 118 of the foot to be corrected need be adjusted to prevent the undesired positioning of that foot. The other swivel means 118 can be permitted to swivel as desired, for example by removing the screw which limits movement. In this manner, virtually free movement as desired of the normal foot is allowed while the undesired movement of- the foot to be corrected is prevented. As with foot splint 112, during walking, the foot to be cor¬ rected can only be brought up to a position laterally opposite the normal foot.

Instead of shoe engaging plate 16 as depicted, a number of other shoe engaging plates could be provided. For example, in U.S. Patent No. 4,249,523 (mentioned above) which patent is hereby incorporated by reference, a shoe engaging plate and an associated plate pivot means could' be provided with the present invention to allow rotation of the foot of the user about an axis that is parallel to the longitudinal axis of the connecting means. In addition, the above mentioned patent also discloses a means for exactly positioning the angle of the foot which could be used in conjunc- tion with the swivel means of the present invention.

Thus, while the present invention has been described with respect to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that variations and modifications can be effected within the scope and spirit of the invention.

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