~ he present invention relates generally to ortRopedic de~ices and mcre partlc~larly, to ankle brace~
for stabilizing the ankle agalnst inversion and eversion without limiting normal plantoflexion and dorsiflexion of the ankle.
In the management of certain injuries to the lower extremitie~ such as fxactures of the tibia and ~lbula, malleolar ~ractures, or ~evere ankle sprains it 1s common to completely immobilize the lower extremity t~ollowlng open or closed reduction in the case o~ ~racture~) by use of the well known molded pla~ter or re~ln cast.
Once the ln~ured extremity has become stable howe~er, lt has been found that recovery may be effected more rapidly by gradually and progressively permitting the extremlty tc bear welght and undergo other permitted exerclses. Thu~, for example, during a second stage of management, a walking heel may be attached to a long plaster coa~t or the latter replaced by a shorter unit 2Q or by a walktng cast specifically adapted to facilitate ~uch maneuvers. One ~orm o~ walking cast commercially a~ailable under the trademark AIRCAST and described in my prior patent No. 3,955,565, consists of a pair o~ radially tele6coping plastic shell members fitted snuggly about the lower extremity and havi~g disposed lnteriorly thereof a plurality of inflated airbags which fill the voids between the outer shell members and tbe lower extremity. While the latter form of walking aaat ha~ the advantage of being removable ~nd of being ~,~
~33349 readjustably conformable to the lower ext~emlty thereby promoting comfort, it still substantlally lmmobillzes the lower extremity when being worn.
A need exists therefore, for an orthopedic device 5 which permits substantially normal planto flexion and dorsiflexion movements of the ankle, but limits inversion and eversion thus stabilizlng the ankle, and which incorporates the advantages of being removabLe and easily reapplied, and further, of being readjustable to conform to the lower 10 extremity thus promotlng comfort.
According to the Lnvention there is provided orthopedic apparatus for use in connection with the lower extremity and for immobilizing the ankle against inversion or eversion while permitting planto flexion and dorsiflexion 15 thereof comprising: a base portion and a pair of spaced-apart sidewall portions attached to opposed side regions of said base portion and extending upwardly therefrom to form a generally U-shaped stirrup member adapted to be fitted about the lower extremity with the heel of the lower extremity 20 resting on the base portior. and the upstanding sidewall portions confronting corresponding opposed side portions of the lower extremity, each of said sidewall portions extend-ing longitudinally above the ankle of the lower extremity and having a predetermined lateral extent such that the correspond-25 ing opposed longitlldinally extending side edges of said side-wall portions are spaced far enough apart from each other to define a pair of openings disposed opposite the front and back portions of the lower extremity respectively when said stirrup member ls fitted about the lower extremity as 30 aforesaid, each of said sidewaLl portions being attached to its corresponding base portion side region by means of a flexural hinge so as to facilitate flexure of each sidewall portion toward and away from each other and toward and away 35 from corresponding confronting side portions of the Lower extremity, and a pair of flexible support members, each one of i\
,~.,~, ~33349 -2a-said flexible support members being substantially coextensively disposed in a juxtaposed manner with respect to the inwardly facing surface of a corresponding one of said sidewall portions so as to engage a corresponding 5 confronting portion of the side of said lower extremity when said sidewall portions are flexed toward each other, at least one of said flexible support members comprising an inflatable bladder, and fastening means for maintaining said sidewall 10 portions and said support members in engagement with corresponding confronting side portions of the lower extremity when said stirrup member is fitted about said lower extremity as aforesaid.
The invention will now be described, by way of 15 example, with reference to the accompanying drawings, in which:
Figure 1 is a side view in elevation of the orthopedic device according to the present invention depicted in fitted engagement about the lower extremity of 20 a human;
Figure 2 is a sectional view of the orthopedic device according to the present invention taken along line 2-2 of Figure l; and Figure 3 is an unfolded plan view in reduced 25 scale of the stirrup member of the orthopedic device of Figures 1 and 2.
1~33349 Turning now to Figs. 1 and 2, there i8 schema-tically shown the orthopedic device of the present invention which in it~ pre~erred form comprises an ankle brace generally represented by reference numeral 10. For purpose~ of lllustrating the present inventlon, the ankle brace 10 is shown in Flg. 1 fitted about the right lower extremity of a human with the lower extremity being indicated diagrammatically in outline form by broken lines. The term "lower extremlty" as used herein should be interpreted broadly to include the foot, the ankle, and the lower leg.
Ankle brace 10 comprises a generaIly U-shaped stirrup member 14 which in the embodiment shown is of one-piece construction having a pair of opposed sidewall portions 16, 16a integrally joined to a base portion 18, and a pair of air-inflatable, flexible liners or airbags 20, 20a disposed respectively on the inwardly facing surfaces 22, 22a of opposed sidewall portions 16, 16a in a generally juxtaposed manner coextensive therewith. ~ach sidewall portion 16, 16a extends longitudinally from base portion 18 and has an arcuate transverse cross-sectional shape sufficient to conform generally to the circumferential contour of the lower leg and ankle. In order to accommodate the protruding lateral and medial malleolus on either side of the ankle, respectively, each sidewall portion 16, 16a includes therein respectively, a corresponding rece~s or dished portion 24, 24a defining a gener-ally oblong ~haped cavity disposed in each inner surface 22, 22a with each oblong-shaped recess or cavity its major axis extending generally parallel to the longitudinal axis of each corresponding side portion. Each recess is purposely made large enough so that a stirrup mem~er of one ~tandard size will fit the lower extremities of many different subjects notwithstanding significant differences in age or phYSical size.
~133349 The upwardlyfacing surface of base portlon 18 has a5soclated wlth it another portion which serves a~
a ~upport for the heel and to this end features a rearwardly f~cing boundary having a rounded contour 26 to conform generally to that o~ the heel substantially as shown ln Fig. 3. It will be noted that in the finished article, each sldewall portion 16, 16a may be flexurally displaced relative to bace portion 18 about a corresponding pair of ~lexural axes 32, 34.
Also, to be noted is the fact that the forwardly facing edge 36 of bace portion 18 ha~ a relatively straight contour generally parallel to the central longitudinal axis 38 of each side portion 16, 16a as viewed in Fig. 3 and terminate3 at a point only slightly beyond this central axi~ so as not to limit planto flexion or dorsi-flexion of the ankle.
Stirrup member 14 may advantageously be fabricated from a relatively thin sheet of synthetic thermoplastic polymeric resinous material with -~
the sheet preferably having a thickness in the rangeof about 30 mils to 100 mils. The stirrup member 14 may be formed by injection molding or vacuum or thermo forming in a well known manner. Exemplary thermoplastic materials suitable for use in fabricating stirrup member 14 may be obtained commercially from Rhom and Haas Co.
under the trademark KYDEX; General Electric Co. under the trademark LEXAN; and Borg-Warner Corporation under the trademark CYCLOLAC. Polypropylene or polyethylene which are also widely available commercially may also be employed as a suitable starting material.
Airbag3 20, 20a each comprises a generally elongated, flattened inflatable bladder fabricated as by superimposing two sheets of a relatively thin, flexible material such as vinyl plastic with each sheet having a thickness of about 12 mils, and then heat sealing the sheets together along their common peripheral edges. In addition, each airbag 20, 20a includes a 11333~
~5-one-way or check valve 40, 40a to facilitate inflation thereof with pressurized air and to automatically seal each airbag after it has been internally pressurized.
Since the details of such valves 40, 40a are well known and form no part of the present invention, they will not be further described herein.
~ 7enerally speaking, each airbag 20, 20a is sized and shaped substantially as shown in ~lgs. 1 and
2 so that when they are positioned in a juxtaposed co-extensive manner relative to a corresponding confrontinginside surface 22, ~2a of each sidewall portion 16, 16a, each airbag is adapted to engage the lower extremity on either side thereof, respectively.
Preferably, each airbag ls maintained in position relative to the inside surface 22, 22a of each sidewall portion and relatlvely to the upwardly facing surface of base portion 18 substantially as shown in Figs. 1 and 2 by means of a double faced adhesive patch or plurality of such patches, or other suitable fastening means disposed between each airbag and its corresponding confronting surface 22, 22a of sidewall portions 16, 16a.
Also, if desired a heel pad (not shown) of felt, foamed plastic, sponge rubber, or other suit-able materials may be secured by an adhesive to the upper surface of the base portion 18 in an overlying position.
In order to maintain the ankle brace 10 in proper fitting engagement about the lower extremity, a pair of longitudinally spaced, circumferentlally extending fastener strap members 44, 44a are provided.
Preferably, each fastener strap member is of the well known woven fabric construction sold under the tradmerk VELCRO and is adapted to cooperate with a pair of circumferentially spaced fastener patch elements 46, 46a having the known VELCRO type hook-like extensions therein with the patch elements being adhesively secured in a conventional manner to ~33349 the exte~ior surface of side portion 16 in the position generally shown in Fig. 1 wlth respect to upper strap 44O As is also shown in Fig. 1 with respect to fastener strap 44, one end of each fastener strap is adapted to matingly engage a corresponding patch element so that the strap may then be drawn and tensioned snuggly around the exterior of both sidewall portions 16, 16a in a cir-cumferential manner and the other end of the fastener strap attached to engage the other patch element in which case the completely fastened strap member will appear as lndicated by the lower fastening strap member 44a in Fig.
lo Obviously, other fastening members may be employed instead so long as they maintain the sidewall portions in secure fitting engagement about the lower extremity including for example, wrapped adhesive tape or an elas-tlc bandage.
The ankle brace 10 is easily applied or fitted about the lower extremity with the ankle in the neutral position as shown in Fig. I.
2Q Once the ankle brace has been comfortably fitted, the two strap member 44, 44a may then be cir-cumferentially wrapped about the exterior of the two sidewall portions and-the lower leg and fastened in place with sufflci'ent circumferential tension being applied to each strap member merely to cause the two upper portions of sidewall portions 16, 16a and their corresponding airbags 20, 20a to snuggly engage the lo~er leg~
Each alrbag 20, 20a may then be inflated as 3Q ~y inserting a ~hort length of tubing through self-seallng ~al~es 40, 40a and blowing with mouth pressure.
As lndicated in Fig. 2, internal pressurization of each airbag will cause the inwardly facing wall portions of the airbags to radially expand toward each other un-til they come into engagement with the confronting ir-regular contours of the lower extremity, thus producing a constant pressure supporting air cushion between the 1~33349 irregular contours of the lower extremity and the inner surface~ 22, 22a common to the sidwall portions 16, 16a of stirrup member 14. It has been found that an internal pressure in the range of about 15mm Hg. to about 25mm Hg.
which may easily be achleved by one or two breaths by mouth entubated through the airbag valve produces an air cushion which affords quite firm support of the lateral and medial portions of the lower extremity sufficient to limlt or stabilize the ankle agalnst inversion or ever-sion movements, yet whlch is not great enough to have anydeleterious effect upon blood circulation. Moreover, such inflation of the air bags 20, 20a does not limit planto ~lexion and dorsiflexion movements of the ankle.
A~ter inflation of each airbag 20, 20a the lS foot may then be dressed with a normal shoe as diagram-matically indicated in Flg. 1 and a program of normal walking or running movements gradually commenced as permitted. Advantageously, the ankle brace may periodi-cally be removed to permit whirlpool treatments, bathing, 2Q or rest and simply reapplied in the manner described above when walking or running is to resume. It will be appreciated that owing to inflation of the flexible air-bags 20, 20a the flexibility of the opposed sidewall portlon~ towaxd and away from each other, and the u~e of the circumferentially tensioned strap~ 44, 44a the ankle brace is aut~matically self-adjusting and will comfortably fit the lower extremity even as edema subsides.
~hlle an accumulation of perspiration between the con-fronting inner surface of each airbag and the skin
3~ surface of the lower extremity may be experienced, this may quite easily be c~ntrolled by periodic removal of the ankle brace followed by a bathing treatment or in any case, by the wearing of a conventional sto~king fabricated of moisture absorbent material.
In accordance with another feature of the lnvention it has been discovered that dorsiflexion of the ankle while wearing the ankle brace of the ~133349 --8~
present lnvention causes a momentary increase of the internal pressure of each alrbag to as h~gh as 40-60mm~
Hg. Thus, upon normal walking or running movement, for example there will be manifested a c~clic pressure implulse against the lateral and medial portions of the lower extremity. Whereas, it is known that a steady-state pressure greater than about 50mm Hg may deleteriously effect blood circulation, it is belleved that a cyclic momentary increase of pressure above this level such as the periodic impulses achieved wlth the ankle brace of the present invention are actually beneficial in that the resulting "pumping effect"
actually promotes rather than hinders blood circulation.
In an example of the preferred embodiment of the present invention ankle brace 10 is dimensioned as follows:
stirrup member height: 11.25 inches sidewall portion width ttop): 3.5 inches sidewall portion width (bottom): 1.0 inch ~ase portion width: 2.0 inches base portion lengtho 2.37 inches airbag ~eight including tucked-in portion: 12 inches airbag width (top): 4O0 inches airbag width (bottom): 2.5 inches fastener strap circumference: 13.25 inches fastener strap width: 2.0 inches, The provision of the ankle brace of the present invention facilitates management of lower leg injuries in a gradual or progressive manner. Thus, in the case of fractures te.g., tibial, fibular, malleolar) or severe sprains te.g., collateral ligament tears), the lower extremity may first be immobilized completely by use of a long cast, followed gradually by weight bearing exercises while maintaining substantial immobilization of the lower leg (e.g., via use ~f a walking cast). The ankle brace of the present invention may then be used with a conventional shoe to gradually facilitate normal 33 ~
g walki-lg or running movements, that is substantially norma;
planto flexion and dorsiflexion movements, while main-taining the ankle stable against inversion or ever~ion.
By progres ively disimmobilizing the lower extremity in this regard, it is believed that management of such injuries will lead to more rapid recovery and func~
tionality. With less severe in~uries, the first and/or second stages may be ommitted entirely, and the ankle brace of the present invention used exclusively (or following an initial period of management in a walking cast) to gradually promote normal planto flexion and dorsiflexion movements while main~aining the ankle stable against inversion or eversion.
Obviously, many additional modifications and alterations of the present invention will occur to those with ordinary skill. Accordingly, the present invention should be limited only by the spiri~ and scope of the appended claims.