A brace made of rigid thermoplastic material that retains the corrective features of a corrective cast without the disadvantages of a cast. The brace securely encloses the heel and the medial portion of the foot up to or slightly beyond the tip of the big toe on the medial side only. A strap, adjustably secured to the brace, directs a corrective force on the apex of the deformity on the lateral aspect of the foot, thus effecting correction. The brace has a leg-embracing component which includes a strap for preventing the heel from pulling away from the brace.

BACKGROUND OF THE INVENTION 
There are numerous causes of intoeing in children, including metatarsus 
adductus, clubfeet, and internal tibial torsion. The device of the present 
invention is designed specifically for the treatment of metatarsus 
adductus only. 
Metatarsus adductus is a congenital condition in which the forefoot is 
adducted or turned in relativeto the hindfoot or heel. The primary 
treatment is corrective casting, which gives excellent results. However, 
it has serious disadvantages, including repeated expensive castings, skin 
pressure problems, and potentially diastrous vascular problems. 
Alternatives to casting have been sought over the years, and they basically 
fall into two groups: shoes (or boots) and braces (or splints). In spite 
of several introductions over the years, these alternatives have not been 
utilized to any significant degree, and casting remains even today the 
treatment of choice. The reason is that these alternatives lack the 
features that enable them to correct the deformity. 
Shoes and boots have been ineffective in obtaining correction because, 
being all enclosing, they do not provide enough pressure at specific 
points to effect correction. At the present time shoes are used mainly as 
a holding device after correction has been obtained with casts. 
The braces and splints that have been introduced so far do not hold the 
heel and the medial portion of the foot securely enough to allow for 
successful correction of the deformity; for example, U.S. Pat. Nos. 
3,924,615 to McKim; 3,812,850 and 3,910,267 to Reiman; and the brace 
designed by Lusskin as reported in The Journal of Bone and Joint Surgery, 
January 1951, p. 269. All these devices use straps to hold the medial 
portion of the foot, which is insufficient for correction. 
U.S. Pat. No. 3,973,559 to Reiman attempts to address the problem by adding 
a wall along the medial side of the footplate. This patent is believed to 
be the closest prior art. However, it still does not hold the medial 
portion of the foot securely enough to effect correctoion, and lacks 
several important features that determine success or failure: 
(1) The medial wall extends only to the base of the big toe, and depends on 
the child wearing both footplates attached together in an angular 
relationship, and the child lying prone (on his stomach), and the mattress 
on which the child lies, to effect correction of the bit toe varus, which 
is an important component of the deformity. Hence, the splint has 
cumbersome constraints of wearing both footplates even if only one foot is 
affected, and of posture since the child has to be lying prone. 
(2) The medial wall does not have an upper ledge to prevent dorsal 
migration of the big toe and medial portion of the forefoot, thus escaping 
from the corrective influence of the medial wall. This is very important 
if one realizes how wiggly the infant foot can be. 
(3) The medial wall is straight. This is much less effective than a 
slightly convex border (abducted position) which allows the foot to be 
placed in a slightly over-corrected position. 
(4) The splint does not have rigid support for the lateral aspect of the 
heel to prevent valgus (turning out) of the heel, a complication to be 
avoided in the treatment of metatarsus adductus. 
BRIEF SUMMARY OF THE INVENTION 
The present invention is a brace preferably made of rigid thermoplastic 
material which securely encloses the heel and medial portion of the foot 
up to or slightly beyond the tip of the big toe. The invention embodies 
the three-point fixation principle. By holding the heel and the medial 
portion of the forefoot and great toe securely, the brace fixates the 
adducted foot at two points--the heel, which becomes the first point of 
fixation, and the base of the bit toe, which forms the second point of 
fixation. When these two points of fixation are secure, the third point of 
fixation can then be applied between the first two points by means of a 
strap which directs a corrective force on the apex of the convexity of the 
deformity on the lateral aspect of the foot, thus effecting correction.

DESCRIPTION OF THE INVENTION 
The brace is designed for application to the foot with metatarsus adductus 
(forefoot adduction) to effect correction. 
Referring to FIG. 1, the brace is made of a molded thermoplastic material, 
and consists of a foot component 5, a heel component 6, and a leg 
component 7 that hold the foot in the corrected position. The foot 
component 5 extends from the heel to the tip of the big toe or slightly 
beyond. This is important because hallux varus (turning in of the big toe) 
is a component of the metatarsus adductus deformity, and correction must 
include the big toe as well as the foot. The foot component 5 is C-shaped 
in cross-section (refer to FIG. 4), and embraces the sole and the top of 
the foot on the medial side only. On the dorsal (upper) aspect, an upper 
ledge 8 extends laterally to cover the medial portion of the foot as well 
as the first two toes. On the plantar (lower) aspect, a lower ledge 9 
extends laterally to cover the medial part of the sole of the foot and the 
medial two toes. Horizontal edges 8,9 are important because they hold the 
forefoot securely between them, and prevent the big toe and forefoot from 
migrating upwards or downwards during correction, and thus escaping from 
the corrective influence of foot component 5. Horizontal edges 8,9 must 
not reach to the lateral border of the foot. If they do, the corrective 
force (described below) cannot be utilized. 
It should also be noted that foot component 5 is not perfectly straight, 
but slightly convex medially (abducted) to allow for over-correction if 
necessary. 
The heel component 6 continues backwards from the foot component 5 as an 
integral unit and encloses the heel securely during correction. The 
cross-sectional shape is shown in FIG. 3. It is shaped like a C tilted 
backwards on itself. The heel is seated securely in this component during 
correction, the medial aspect of the heel being held by medial portion 10 
and the lateral aspect of the heel by lateral portion 11. The heel is 
fixated by portion 10 for correction, while portion 11 prevents the heel 
from going into valgus during correction, a posture to be vigorously 
prevented. 
The leg component 7 extends upwards from the heel comonent 6 as an integral 
unit. It has a cross-section like an inverted U, and the posterior aspect 
of the leg or calf rests against it. The angle that the leg component 7 
forms with the foot component 5 is not a right angle, but a slightly 
obtuse angle (plantarflexion or equinus position). Anatomically, 
dorsiflexion of the ankle and valgus of the heel occur together, while 
plantarflexion of the ankle occurs with varus of the heel. Holding the 
ankle in slight plantarflexion therefore helps to prevent valgus of the 
heel during correction. 
The length of the leg component 7 is variable, as long as it is sufficient 
to keep the heel securely seated in the heel component 6, and to keep the 
ankle in slight plantarflexion. 
To hold the foot in the brace, strap means 15,16,17 (FIG. 9) are provided 
which fasten onto the margins of the brace by a velcro touch and grip 
fastener, although any other adjustable means of fastening would do just 
as well. 
Strap 15 holds the leg to the leg component 7. 
Strap 16 holds the heel seated securely in the heel component 6. 
Strap 17 holds the foot to the foot component 5, but more importantly, it 
performs the vital task of applying a corrective force on the apex of the 
convexity 18 (FIG. 9) of the deformity on the lateral border of the foot. 
With the foot securely held in components 5,6, two points of fixation 
referred to in the claims as a "static force", have been established at 
the two ends of the deformity--at the heel and at the base of the big toe, 
as shown in FIG. 10. The principle of three-point fixation can now be 
utilized by applying the third point of fixation at the apex of the 
deformity at 18. This is effected by tightening the adjustable strap 
against convexity 18, referred to in the claims as a "dynamic force". The 
amount of correction can be controlled by the tautness of the strap 
against convexity 18 and this can be carefully graduated over a period of 
weeks until complete correction is obtained. The usual period for 
completing correction varies from six weeks to three months.