US2623307A - Orthopedic insole - Google Patents

Description

Dec. 30, 1952 D. J. MoRToN 2,623,307

ORTHOPEDIC INSOLE Filed June 14, 1950 2 SHEETS- SHEET 1 INVENTOR. DUDLEY J. MORTON ATTORNEYS Dec. 30, 1952 Q 1 MQRTQN 2,523,307

ORTHOPEDIC INSOLE Filed June 14, 1950 2 SHEETS-SHEET 2 INVENTOR. DUDLEY J.' MORTON ATTORNEYS Patented Dec. 30, 1952 UNITED STATES PATENT OFFICE ORTHOPEDIC INSOLE Dudley J. Morton, New York, N. Y.

Application June 14, 1950, Serial No. 168,090

` 3 Claims.

This invention relates to a method and apparatus for treating footl and arch disorders in human feet. l

In the accompanying'drawings':

4Figure l is a view 'of a normal human foot showing the weight load on the metatarsal bones;

Figure 2 isa view of a human foot where deficient support by metatarsal I through shortness or looseness, identifies the distorted weight distribution. The abnormal overload on metatarsal II and III is the basic factor in causing progressive deformity in bone structure and painful damage to the soft tissuesas herein described;

Figure 3 is a view of a vhuman foot as shown in Figure 2 but with the instant method applied so as to correct the abnormal condition and restore the weight distribution to that shown in Figure 1;

Figure 4 is a view looking down upon a left insole constituting an apparatus suitable for practicing the herein disclosed method;

Figure 5 is a bottom view of the insole Figure 4; Y

Figure 6 is an edge view of the insole, Figure 4 with the parts separated to show their relative position before being secured together; and

Figures 7 to 10 inclusive, are sectional views on the lines 1 to l0 inclusive, Figure 4.

In order to properly understand the following disclosure of the method and a preferred form of apparatus for practicing the same, brief reference will be made to some fundamental facts respecting the human foot, which must be understood before this method can be applied to the correction of foot and arch disclosures.

The framework of the human foot (composed of the combination of solid bone segments with the effective cohesion of the ligaments which bind them together), is the 'means ywhereby weight stresses are sustained and transmitted from the ankle to the pointsof contact of that framework with the ground; namely, the heel in back and the front ends of the metatarsal bones in front. Thus, the bones of the feet have the most intimate and primary working relationship with the force of gravity in the interaction between foot structure and that external force. vWithout their bony framework, the feet would tbe useless as weight-supporting and locomotive organs.

This primary relationship has been only vaguelly recognized and completely overlooked in the prevailing concepts of foot function and of -disfordered function.

Primary importance is wrongly ascribed to the muscles and to weakness of the muscles, and often foot specialists fail to understand that the foots bony framework is comp-arable to the chassis of an automobile for the support of gravitational stresses either when stationary or in action; While the muscles are comparable with the motor whose kinetic power is concerned only in moving the load borne by the chassis.

With bodyweight (gravity) recognized as the only mechanical force, habitually operating upon the foots framework and of magnitude capable of damaging action, it is essential that the division of bodyweight be known from the points of reception (ankle) to each of the points of weight-bearing contact with the ground; namely, the heel in back, `and in frontthe front ends of the ve metatarsal bones. Measurement of the downward force by instruments designed for this purpose gave two distinct patterns of weight distribution as characteristic of normal function (1) in standing and (2) in locomotion. With total bodyweight reckoned as 24 equal units (for example, in a lb. individual each unit would be l2242=5 pounds) the distribution in standing would be as follows: 12 units (60` lbs.) would be transmitted down each leg to the ankle. From there, 6 units (30 lbs.) is transmitted to the point of heel contact; the other 6 units (30 lbs.) are transmitted by the metatarsal bones subdivided so that 2 units (10 lbs.) is borne by metatarsal I, and 1 unit (5 lbs.) is borne by each of the other four metatarsal bones.

These measurements demonstrate ye facts of fundamental importance.

1.Each metatarsal bone has normal weightbearing contact with the ground. i

2. The fallacy of the traditional concept of a transverse arch as formed by the front ends of the metatarsal bones, with metatarsals I and V bearing on the ground and the middle ones, II, III and IV, occupying an elevated arched position. That faculty premise is necessary to the erroneous explanation of metatarsal disorder as due to a downward displacement (falling of the alleged metatarsal arch) of the threemiddle bones. f

3. The equal division of the 6 metatarsal units (3 and 3) on each side of the foots central axis (running between metatarsals II, and III) indicates that the structural stability (balance) of 3 the foot from side to side is furnished by metatarsal I on the medial side, and metatarsal V on the lateral side.

4. The major role of metatarsal I becomes apparent because (1) it is located on the inner border of the foot; (2) and therefore is primarily for the support and stability of the foot structure along this elevated and arched inner border; and (3) it normally carries the greatest share of bodyweight in the front half of the foot.

5. Hence, its major role makes it the member most disruptive to normal foot function if or when its ability to supply proper support is impaired Vor defective.

However, the most conspicuous evidence of the major importance of metatarsal I is shown in locomotion during the phase when the entire bodyweight is borne on one foot andthe heel is lifted from the ground in propelling bodyweight forward. During these moments, the entire load .(24 units) is carried by the metatarsal bones. I-Iere the distribution vfollows a pattern in Which half of the .load ('12 units) is sustained by metatarsal I and the other half (l2 units) is distributed among the ,fourlateral metatarsal'bones. Thus, metatarsal I is called upon to sustain a load as great as 'is required ,of the large ,bones of either leg during the act of standing.

Disordered weight-bearing, ,all vdegrees Yof postural instability and unbalance, or ultimate breakdown of the foots arched contour must find its primary source in the defective support by one supporting member. That member .is clearly identified by the character and location ofthe symptoms and signs observed ,in .the ,two most common types of foot disorder. They are commonly spoken of as falling of the (longitudinal) arches, and dropping of the metatarsal arch.

This will lbe -understood by referring to Figure 1 .showing the weight distribution in ya normal foot. Here the vblack areas indicate metatarsal load in the ratio of 2l-1-l1. VIt will be observed that, just -as a chair with a loose leg inevitably tilts in the direction of the loose leg, an habitual inward tilt of the foot points directly to deficient support by the supporting bone on the inner border of the foot due to laxity or looseness in its attachment to the main framework.

Also, to demonstrate that it is not caused by muscular weakness, a foot that possesses normal distribution of Weight to all points of ground contact, maintains a balanced normal `posture under bodyweight even vthough all the ,leg muscles to the foot are paralyzed.

Deficient support by the loose chair leg inevitably causes exaggeration of weight to'be borne by other legs. When metatarsal I fails to supply its normal share of support through laxity of its basal joints (intercuneiform and naviculocuneiform), the unsupported share is transposed to metatarsalII, and to a 'lesserdegree to .metatarsal III, as indicated in Figure 2. This habitual transfer of excess weight on metatarsal vII is demonstrated structurally in a progressive enlargement .or strengthening of the shaft of that bone by an increase in vits diameter and/or `thickening of its cortex. Skin callus appear in adult feet at X under the front end of that bone, and muscle pains result frequently from faulty overstrain on .the muscles because of the unbalanced foot posture.

The foregoing condition is illustrated in Figure 2. Here metatarsal I is defective (although the foot may be well arched and posture good). The weight, as indicated 'by the black areas, is

4 transposed to metatarsal II and, to a lesser degree, to metatarsal III.

The second type of disorder is located chieny in the metatarsal region. It occurs predominantly in women in association with the continuous use of high heels. Since all metatarsal bones have direct weight bearing contact with the ground in normal function, there can be no downward displacement to explain the occurrence of painful symptoms in this region. vAlthough the disordered weight distribution of a loose metatarsal I frequently causes metatarsalgic symptoms, deficiency of support by this bone due to shortness is more specific-ally the direct cause of this more localized disorder.

With a short metatarsal I, weight distribution may not be seriously affected when the feet are in a position of normal standing--with heels on the ground. However when the heels are lifted in locomotion and weight is thrown upon the forepart of the supporting foot, the more advanced position of the front end of the longer metatarsal II causes the major share of bodyweight to become increasingly concentrated upon that boneinstead or" upon the shorter metatarsal I. Enlarging development of metatarsalII and III are oftenconspicuously seen inX-ray pictures of these feet. The prevalence of painful symptoms of this type of disorder in w-omen is clearly explained when the heels are kept in an elevated position both in standing and locomotion by the use of their .higher shoeh'eels. The skin calluses x, 'Figure 2, under the front end of that bone which is so common `in Women is a striking demonstration of the disordered weight distribution upon the metatarsal bones.

Avoidance or correction of the disabling symptoms of foot disorders requires recognition of these two principal `phases of damaging action that results from improper distribution of the bodys weight stresses through .the feet. The primary phase pertains to the bones of the feet as the direct medium for the foots action against the force of gravity. The accompanying underloaded segments are lof course, not involved in such danger.

For illustration.-If of two persons of the saine weight, one had normal weight distribution through the feet, `and in the other, certain segments of his feet carried an abnormally large share of the load, while other segments carried `less than normal; it would not be diflicult to predict which personwas most likely to develop fooi'l trouble and just Where in lhis foot structure the liability is located.

The herein disclosed method of establishing freedom from the injury of `disordered function inthis primary 'phase is to eliminate or dissipate from the overloading segments the weight stresses which are in excess of the normal share of load those par should carry; i. e. by establishing normal weight distribution.

The secondary phase of damaging action is that which is incurred by the soft tissues through localized abnormal pressures and faulty distorted and exaggerated strains. Since the nerves are most intimately associated with the soft tissues, this lphase includes all the painful symptoms and neurological disturbances that are typical of these disorders. The abnormal pressures are identied in the excess weight which the front end of the overloaded metatarsals transmit to the small area `of flesh and skin immediately beneath them. This concentration of intensied pressure produces a traumatic irritation of the tissues and imbedded nerves that causes the typical burning sensation of the soles. Under continued function, it causes more rapid proliferation and growth of skin cells which results in the formation of localized calluses which become an added source lof painful symptoms.

Faulty strains are imposed upon the ligaments because of abnormal transmission of weight stresses through the contact surfaces of the joints. These strains are caused either by uneven contact of adjacent joint surfaces through forced disalignment of the bones from faulty posture or by an excess load on such joints. Strains of this sort are identified by points of localized tender ness in the region of the affected joint or joints and of their ligaments.

Other strains are the ones imposed upon the muscles. They result: (l) from an unnatural and abnormal load being deected on the muscles because of postural unbalance (pronation) of the feet, or (2) from sustained over-activity of the muscles to protect the feet from pressure upon some painful weightbearing point such as a painful callus. These strains produce the muscular symptoms of early fatigue, aches, and spasms in the feet and legs.

The two phases of damaging action, on bone and on soft tissues, require different but desirably coordinated methods of treatment as herein described, to help to counteract the primary causes and symptomatic effects ici. these common types of foot trouble. Analysis shows that olecient support in weight bearing by metatarsal I is the direct mechanical cause. That deficiency is due to a laxity and/or a shortness of this ysegment. It can be directly overcome as taught herein, .by the intervention of a piece of solid material I5 between the front end of that bone and the ground, of sumcient thickness to eliminate the slack in ligaments when the segment is loose, or to compensate for the needed length when that segment is short. Just as a suitable block placed under a short leg of a table stabilizes the table and establishes equal distribution of weight on all four legs, this procedure stabilizes the entire bony framework of the foot and eliminates or modifies the damaging element of overload by a more normal redistribution of body Weight. This is the basic mechanical feature of the compeneating insole herein described, because it effects foot function at its Very source in bone structure.

Also, by establishing firm supporting contact of metatarsal I with the ground, the entire floot structure becomes stabilized, thereby correcting faulty strains on ligaments and muscles that result from postural insecurity. (pronation).

The second important feature of the device described herein provides a means lto counteract the excessive bruising pressure on the soft tissues which have been concentrated upon the small areas immediately under the front ends of the overloaded metatarsal bones. When such pressure points have caused painful irritation of these tissues (traumatic) cellulitis with nerve involvement, and have induced the formation of calluses, it is often insufficient merely to reduce the overload ion these bones toa normal load; because under total bodyweight, even normal degrees of pressure in these localized irritated areas is too severe for the chronically bruised and inflamed state of these tissues and for the hypersensitive and highly irritable state of the nerves. Even normal pressures will perpetuate the state of cellular irritation and pain. It is therefore necessary to minimize weight stresses on those 6 localized points that have been subject to the damaging action of concentrated pressure. This is accomplished by diffusing the pressure as widely as possible over adjacent areas; and the most effective means of doing so depends upon three yspecifications in its design.

1. The weight-diffusing element must be made of pressure-sustaining material (preferably of moderate resiliency).

2. The tapered front margin of the element must be in immediate relation to the rear margin of the small metatarsal area of ground contact. The taper is of an angle to supply counter pressure against the tissues under the metatarsal shaft and thereby increase posteriorly the area of transmitted pressure so that the 'localized intensity of pressure becomes reduced according to enlargement in the area of transmission.

3. In order to gain greatest reduction of irritating pressure on the irritated spots, the device is extended across the foot. In this manner weight stresses can be diffused over the largest area and encourage the forepart of the foot to perform its full range of normal weight-bearing function.

Now, referring to Figures 4 to 10, inclusive, a compensating insole will be seen suitable for use in practicing the method herein disclosed.

While a shoe can be constructed to permanently embody in the shoe structure the platform and weight-diffusing elements hereinafter described, the preferred means is to provide an insole having these elements, as same constitutes an article easy to manufacture and which can be applied by the user to any shoes, thereby obviating the necessity of having special shoes made to order.

Referring to Figure 4, the numeral il denotes the upper layer top member of the insole and is made of leather or the like. It fits into the shoes and extends from the extreme rear point I2 of the heel to a point I3 just below the ball of the foot and behind the juncture of the four metatarsal bones and their phalanges.

The top I I is formed with a forwardly extended portion I4 which extends under the front end of the first metatarsal and forms (together lwith pad I5) a platform to compensate for any shortness or laxness in this metatarsal and to restore even weight distirbution for the reasons previously explained. The total weight is now redistributed from its faulty ratio shown in Figure 2, to its normal ratio as shown in Figure 3, and therefore conforms to Fig. 1. Thus, one object of the in vention is attained; to wit, correction of weight distribution due to metatarsal disorder.

The pad I5 is made of the necessary thickness to suit the foot to which it is applied, bearing in mind that even weight distribution should be attained, as described in connection with Figure 1. When so applied, the foot condition is corrected from that shown in Figure 2 to normal, Figure 1.

Referring to Figure 6, the top member I l carrying the pad I5 has a stiffening liner Iii of any suitable material such as commonly employed for such liners cemented or otherwise secured thereto, and same covers the insole from heel I2 to a point I1, a short distance in front of the upwardly curved instep portion i8 of the insole.

A bottom member I9, preferably of leather, is now attached to the base I I and is of exactly the same shape as II. The stitching 2t may pass through the liner I6 of any desired thickness.

The outer edges of members I9 and II may be cemented together'a-nd tooled to present a closed rounded -edge,-'and the curved instep portion I8 maybeformed in the 'insole by pressing same to the `desired shape.

The entire insole unit may, if desired, be pressed or otherwise shaped to conform generally to the bottom of the foot, provided the pad i5 and member 2l (hereinaftervdescribed) are so placed as to function as herein described when said insole is so shaped.

The second essential object or this invention, to'counteract the excessive bruising pressure on the soft tissues immediately under the front end `of overloaded metatarsal bones, is attained by securing a weight-diiusing element or member 21 to member l by cement or any other suitable manner.

The element 2l maybe of rather dense sponge rubber or 'the like, but is not to be considered as aipadfor support, as its real function is to distribute the weight applied `thereto by the four lateral metatarsals after same has been corrected as just described over a considerable area as defined by said member which, as best seen in Figure .5, will underlie all the metatarsals immediately rearwardly of the contact points thereof, andthen extend rearwardly toward the heel a suiiicient distance to diiuse the weight applied during 'weight-bearing.

`It will tbe observed that the member 2i does not e'xtendto or 'support the arch of the foot and does'not come Ynear'the tai-sal bones.

The edges ofthe member 2l may be rounded to `present a neat appearance and it may be tapered toward the -front and rear edges as shown by dotted lines 22, Figure 6.

Referring to Figure 2, it will be seen that with 'the rst metatarsal in the condition described, heavy callus appear under the second and third .metatarsals This is due to the abnormal distribution of weight, as previously described, and this condition is corrected by applying the member ZI which, together with pad l5, acts to diffuse the weight over the surface enclosed by dotted lines 23 Ain Figure 3, the second main object of this invention being thus attained.

Other objects and advantages of the invention will be apparent from the foregoing, this disclosure being illustrative and not limitative of the invention. Many modifications can be made by those skilled in the art, and therefore the invention is as dened by the appended claims.

What is claimed is:

1. An insole vadapted to be inserted in a shoe and comprising a member adapted to underlie a human foot and having a front extension radapted 'to extend only under the forward end of the first metatarsal bone of the foot, a noncushioning pad secured to said front extension and underlying the head of the rst metatarsal bone only and adapted to compensate for shortness or laxity of said first metatarsal, and a weight-diiusing cushion member secured to the bottom of said insole and underlying the shafts of all the metatarsal bones from a point im ediately back of the heads of all the metartarsals 8 and adapted, when in a shoe, to diu'se pressure vover an area extending behind and transverse said insole, said weight-diiusing cushion member extending laterally across said insole substantially the full width thereof.

2. An insole adapted to be inserted in a shoe, and comprising top and bottom members adapted to underlie a human foot and having a front extension adapted to extend only under the forward end of the rst metatarsal bone of said foot, a non-cushioning pad secured between said front extension and underlying the head of the iirst metatarsal bone only and adapted to compensate for shortness or laxity of said rnetatarsal, means for securing said members together with said pad therebetween, and a weight-diiusing cushion member secured to the underside of said bottom member and extending transverseiy of same, and underlying the shafts of all the metatarsal bones from a point immediately back of the heads of all the metatarsals and adapted, when worn in a shoe, to diuse pressure over an area extending behind and transverse ysaid insole, said weight-diffusing cushion member extending laterally across said insole substantially the full width thereof.

3. An insole adapted to be inserted in a shoe and comprising top and bottom members adapted to underlie a human foot inY said shoe, said members having a front extension adapted to extend only under the forward end of the rst metatarsal bone of said foot, a non-cushioning pad secured between said front extension and underlying the head of the first metatarsal bone only and adapted to compensate for shortness or laxity thereof, a stiiening element secured between said members and extending from the heel to a point forward of the instep of said insole, means for securing said members together with said pad and said stiiening member therebetween, and a weight-dilusing cushion member secured to said insole and extending transversely of the same and forward of said stiffening member and underlying the shafts o all the nietatarsal bones from a point immediately back of the heads of all said metatarsals and adapted, when worn in a shoe, to diffuse weight over the entire area defined by said cushion member, said last member extending laterally across insole substantially the full width thereof.

DDLL'Y J. VRTON.

REFERENCES CTED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,841,942 Fenton Jan. 19, i932 1,847,973 Morton l, 1932 1,849,734: Scholl Mar. 15, 1932 2,148,999 Schur et al Feb. 23, 1939 2,231,551 Sewall Feb. l1, 104i 2,287,341 Burns June 23, 194:2 2,423,522 Samblanet July 8, 1947

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