GB2443557A - Removable total contact cast - Google Patents

Abstract

The removable cast includes two tubular support members either side of a heel and extending behind the ankle area of a wearer. The support members comprise a plurality of rigid high temperature thermoplastic components with or without reinforcing composite fibre infill, to support the under surface of the foot, contain the back surface of the leg, and sweep behind the ankle. The components are selected for a specific contra-lateral limb from several sizes according to foot length, body weight, head height and heel width. All of the components, which are inter-joined by fastening means 30 are arranged to provide a rocker sole for a user.

Description

Background

There are various requirements for a removable total contact cast walker to be of real use and value in the clinical arena: 1) Immobilise Lower Limb like a Non-Removable Total Contact Cast.

2) Be Robust Against Forces during Gait Cycle.

3) Be Affordable to Mass Manufacture Several components 4) Be quick to apply to patient and removable, so that whole cast doesn't need to be destroyed and remade saving time and costs, also avoiding a "claustrophobic-like response" from patient and non-compliance.

Alternatively, for enforced compliance, outer retaining straps can also be replaced with one or two layers of plaster bandage, saving costs of overall materials compared to serial casting.

1) This invention aims to break new ground in providing a unique ergonomic rigid assembly to support and contain formable panels and insole to provide a removable total contact cast walker that can be selected over several sizes, tailoring to a specific contra-lateral limb from below the knee, through leg, ankle and foot Where the assembly is made from adjoining 3 vacuum formable components, comprising of; footplate, leg component and an outer bracing frame with a Rocker sole.

The problem with existing cast walkers is they are linear and tend to come in just 3 or sizes containing left and right limbs. In short they are too box like, requiring too much cushioning material, in order to contain a wide variance of limb topography.

The design and shape of conventional cast walkers doesn't allow a greater size range.

Better functional immobilization for a lower limb total contact cast can be defined as having a minimum thickness of cushioning material under the foot sole, around the fibula malleolus of the ankle and lower shaft of fibula on the lateral side, around the tibial malleolus of ankle and the medial side and up shin and over and around the dorsal retinacula portion of foot by contouring to these areas through total contact casting.

2) A rigid immobilising cast for the lower limb undergoes high forces. Off the shelf or customised ankle foot orthoses report frequent failure and the non-removable total contact cast also degrades and deforms with gait forces.

The rigid novel cast assembly addresses the prime force responsible through the ankle area during the propulsive phase of gait through two tubular-like beams either side of the ankle formed from the interconnecting rigid components.

3) The rigid components are vacuum formed from high temperature thermoplastic sheets with or without composite fibre reinforcement within the plastic sheet.

Several components can be vacuum formed from one sheet and cut from one undulating mould block. Providing a feasible way to increase the sizing options to tailor each assembly to a specific patient.

4) Formable panels and insole of; polyethylene/ polyurethane! low temperature thermoplastic/fabric and/or other viable materials along side hooks, rivets, fabric are fastened to inner periphery of rigid cast assembly and formed to contour of foot, ankle and shin, and held fast around remaining soft tissue and limb through further retaining fabric, straps and clasps externally attached to rigid cast assembly.

This enables this novel total contact cast to be removable and replaceable. So limb can be assessed, redressed, washed (or scratched to alleviate an itch) without destroying and remaking the cast or incurring a claustrophobic like response and non-compliance to attending a casting clinic. 2.

Summary of the Invention

With the novel rigid cast walker frame, the ergonomics and parameters of the human leg, ankle and foot are considered to provide a larger size range and provide a support for formable attachable panels that require less cushioning or pneumatics to contain a specific contra lateral limb (left or right), for a specific foot length and distance from heel to the ball of the foot and termination of the medial longitudinal arch on the footplate. The arch height and lateral drift of medial side of the mid-tarsal area of foot is compensated for through the formable insole layer.

For each specified foot length for a specific contra-lateral limb, there is also a choice of heel and ankle width, I.E., narrow to medium or medium to wide, assessed by knowing the patients weight and height.

The parameters of tibial varum are considered, whereby the contours of said leg and footplate components contained within outer bracing component contain both a tibial varum type leg and ankle or a straighter, less bowing type of leg. Both be contained within this cast assembly through lateral drift of the attached formable panels to the edges of the rigid assembly, where this novel rigid frame is unique in both providing a robust assembly against propulsive forces during gait cycle while falling behind the ankle area to enable attached formable panels to encapsulate the bones of the ankle and shaft of fibula and shin in an optimum stream-lined fashion.

This enables the formable panels to cleave to and apply equal mm-by-mm pressure to said bony facets' curvature and topography. This reduces the by volume and thickness of the cushioning material, in a similar fashion to a fabricated non-remove-able below the knee total contact cast.

The outer bracing component has 2 parallel D' shaped areas perpendicular to axis of propulsion and ground lying in the sagittal plane directly in line with said force.

The 2 D' shaped areas and outer bracing component are further augmented by attachment of foot and leg components. Where the leg and foot rigid components adjoin at a seam through heel and apex area and at common points behind and below fibular and tibial malleolii where these upper flanges on the foot and fore flanges on leg components curve into the sagittal plane and abut to straight line edge of both D' shaped areas of the outer bracing component. The foot and leg components are further adjoined to outer bracing component at the centre of the heel and forefoot and behind the heel and about 1/3 of the way up the centre of the leg, where the foot and leg components touch the outer bracing component. All said rigid components connected by rivets and/or strong bonding adhesive.

Reflected flanges on the lower rim of the leg component above and behind the ankle area increase contact within outer bracing component above and behind D' shaped flat areas, helping to counteract is transverse rotation forces. These two connecting areas can be bonded or held fast through external strapping.

Further augmentation occurs through a central corrugation running from behind the heel to the forefoot under the "Rocker sole" facet in the outer bracing component.

The corrugation attenuates at the mid-foot portion under the "Rocker sole" forming an H' shape when viewed under neigh outer bracing component, helping to further augment structural integrity of component and assembly.

The two under corrugations curve upwards from the mid foot area to the ball of the foot and bring the fulcrum and axis of propulsion during the toe off stage of gait closer to mid foot area, reducing ground reaction force from toe or ball of foot compared to a flat rigid sole. Where the two corrugations raise from the ground level symmetrically providing a linear axis perpendicular to D' shaped areas.

A removable ergonomic cast that conforms to the bony and weight bearing topography of the sole, ankle, shin and dorsum of the lower limb using a minimum volume of cushioning material to achieve better immobilization of lower limb, compared to conventional less ergonomic removable cast walkers, which require more padding or pneumatics to contain a broader range and size of lower limb topography (and not usually designed for a specific contra-lateral limb (I.E., left or right)}.

Being more streamlined in shape to a specific limb also makes it less bulky and less prone to patient non-compliance.

The cast is removable and can be replaced without serial casting, due to detachable formable panels externally strapped fast to the rigid ergonomic frame assembly.

Said rigid frame could be made from three vacuum formed high temperature thermoplastic components from flat sheets, enabling costs of providing vacuum moulds for mass manufacturing several component sizes less expensive than injection moulding.

Increasing the number of rigid components reduces the thickness and volume of cushioning material by reducing distance of formable attached panels to bony and weight bearing areas and allows the thickness of the rigid components to be stream-lined to the stress and weight requirements of the individual, these can be gauged and selected according to body weight, head height and foot length.

Said rigid assembly has holes and detachable rivet points and external straps to firmly house detachable panels comprising of a high tensile outer fabric and low temperature thermoplastic and/or polyethylene/polypropylene or other formable material that can conform to lower limb bony and weight bearing areas.

A separate low temperature thermoplastic insole fits between two side panels and below two leg panels.

The height of the removable cast is streamlined through a few degrees of ankle dorsiflexion within rigid assembly design and by raising attached formable insole layer at toe area, thus reducing need for heel lift on contra lateral shoe or awkward gait due to limb length discrepancy between contra lateral heel and sole height of patient to ground.

Said rigid assembly comprises of two or three high temperature thermoplastic components (with or without composite fibre reinforcement infill) of; a foot, leg (or foot and leg) and outer bracing component. (OBC).

The leg and foot components adjoin to each other through ankle area and at points within the peripheral margins of the OBC and between its two corrugations which also form curvature of a Rocker sole cast, which reduces ground reaction forces off fore foot area of rigid cast assembly by bringing the axis and fulcrum of propulsion during toe offstage of gait closer to heel.

Essentially it is robust against propulsive forces during gait cycle, which has been noted for failure breakage in off the shelf and customised anlde foot orthoses, through ankle area. Structural strength occurs through two parallel portions in rigid component structure behind and below and either side of the ankle area that help strengthen the device during toe off stage of gait.

[By definition, a Rocker sole is a sole with a curvature starting around the mid foot area sweeping up to the ball of the foot, that reduces the need for toe dorsiflexion and removes force from fore foot area further back to mid foot area during the propulsive phase of gait. It enables a smoother gait during gait cycle from mid stance to toe off phase of gait in a shoe or a rigid cast.]

Detailed Description of the Preferred Embodiments

The ergonomic parameters of this device are considered in the anatomical fields of, 1; frontal plane, 2; transverse plane and 3; sagittal plane.

The primary base point parameter is the apex of the heel 4 and the second base point parameter, the weight bearing bisection of the ls metatarsal head 5.

These two points in the transverse plane specify the foot length, allowing a few mm forwards and backwards due to overlying thermo-formable insole layer thickness to allow differences in toe/foot length ratio to a medium toe length selected foot plate and rigid assembly according to specified foot length and corresponding shoe size.

Figs 4,5,6 and 7 show the range of foot type parameters in the transverse plane with a common fixed l metatarsal to heel apex length, from a clinical; adductus, abductus, mild hallux abducto valgus and severe hallux abducto valgus with tailors bunion.

Fig 7 shows overlap of different foot types with common base points 4&5 through 6,7,8 &9, where Fig 9 shows the transverse plane parameters of the rigid foot plate component needed to support heel, arch and weight bearing metatarsal heads through l' to 5th Figs 9&lO show the differences in arch height and forefootlrear foot camber needed to be conformed to, through formable insole. Where for example a flat foot will depress mid potion of formable insole.

Fig 12a shows the two extremes of leg/ankle types; with 17 outlining a tibial varum type leg and 19 showing the frontal plane parameters of a tibial valgum or neutral type of limb, where both limbs are sketched from plaster casts and have the same metatarsal/heel length. The dotted line 20a shows the generic midline between the two types, and minimum coordinates needed to encompass both with this style of cast walker for a fixed choice of heel and ankle width within the 3 rigid components.

Fig 12e shows the overlap between a varum limb and the generic frontal plane coordinates of the leg (foot) and outer component. Fig 12f shows the overlap of a valgum type limb and rigid cast assembly through frontal plane.

In terms of streamlining the width of this type of cast assembly, for more severe types of varum or valgum limbs, there is also a measure of lateral give in the frontal plane through the fatty padding either side of the heel and through the upper wings of the leg component, where the rigid assembly and semi-rigid components can be strapped firmly together around dorsuin of foot, ankle lower and mid leg up to the top of leg component, which has a certain measure of flexural give, before strapping firmly in place. Figsl2 b, c &d show transverse plane cross-section of 24 upper wings of leg component (without semi-rigid panels and external concentric strapping in view).

Fig 20 shows transverse plane cross section of outer component choice of heel/ankle width for one specific size and contra-lateral limb, whereas, figs 25&26 show two generic sizes covering UK sizes 6-12 for a common pneumatic walker, all in the transverse plane. S.

Fig 8 shows the transverse plane outline requirements to support the weight bearing metatarsal heads (1 to 5th), where Fig 11 outlines the foot-plate parameters, Fig 27 shows how the formable side foot flap/panel can expand laterally to underpin the weight bearing 5th metatarsal head (concentric external strapping holding assembled components in place is omitted from diagram).

[An alternative method of attaching formable panels is outlined through Figs 32,33,34,35 and 36, where 74 and 75 are detachable popper rivets/studs fastened through 77 holes in 76 a retaining belt stitched at 72 point on 54 formable side paneL/flap, where 73 are recesses in foot component to receive said popper rivets.

Popper rivets and retaining strap are also attached to Outer Component, holding retaining panel firmly in place against 78 formable insole component.

Retaining hooks 79 (shown in Fig 39, holding fast through 80 retaining outer strap holes (as shown in Fig 38), prevent popper rivets from being pulled out from Outer Component and leg component, which attach to outer retaining straps 81, through holes in straps 82 as in Fig 40. Said straps join to "hook and loop" attachment that passes through 83, buckle and over laps to hold cast panels fast to limb.

84 and 85 are recesses to contour to and support 73, recesses in footplate component (to keep height of insole and side panels linear in the vertical plane above popper rivets).

Fig 42 shows transverse view of insole component, where 86, sides around toes overlap 87, sides of reflected vamp and tuck under 88, cross section of upper overlapping side panels, raising / dorsiflexing toes (48) and reducing heel and sole height requirements. Augmenting 47, the three to five degrees of tolerable ankle dorsiflexion through heel to forefoot and ground camber of rigid cast component assembly to ground and obtain, 47a, the ten degrees ankle dorsiflexion needed to allow toe clearance during heel strike, mid-stance and propulsive phases of gait cycle (outlined in Fig 24 in the sagittal plane).

Regarding the structural integrity of the rigid cast assembly, Fig 13 shows back of 37, rigid leg component with 25, reflected portions and 37a, point of bisection of straight line edge of D' shaped areas within rim of outer component and end of seam attachment to foot component in frontal plane. Fig 14 shows these in the sagittal plane. 36 outline connection points in Figs 16&l 7 to help assembled cast components resist rotation forces in transverse plane. Held fast within Outer Component through 81 external strapping.

The major force to resist during the gait cycle is addressed at 35), near parallel D' shaped areas perpendicular to the axis of propulsion during toe off stage of gait, further augmented by tubular-like convex beams (seen behind heel at 45) occurring between 41,38 and 37, namely three rigid components. [Although not detailed in the diagrams, there is a slight increase in width at the fore end of the D' shaped areas to help ease release of component from vacuum forming mold].

Said rigid components connect at 43,44, 35, 37a, 57a, 56, 57, 15, 36, and 25, through bonding adhesive and/or recessed popper rivets. Two contra lateral corrugations 42 help augment structural integrity of assembly and provide Rocker sole 49a. (-p

69, 54 and 53, formable panels of either low temperature thermoplastic or polyethylene/polypropylene are held in a fabric outer sleeve 54a and attached to high temperature thermoplastic components through hooks, holes, rivets, inner belts, external straps, hook and ioop, buckles; 81,88,83,75,74, 76, 79, 82,81, 52 and 51.

The insole component 87 protects toes and slightly reduces sole and heel height.

Guide to Drawings Diagram 1) Fig 1 Anatomical body plane reference terminology, I)= Sagittal plane, 2)=Frontal plane, 3) =Transverse plane.

Diagrams 2) Fig 2 1St metatarsal head length (as measured from weight bearing tangent/center of metatarsal head to behind heel apex) in transverse plane.

Fig 3 " " in sagittal plane. 4) = apex of heel 5) = line through weight bearing center of 1st metatarsal head..

Diagram 3) Fig 4 Transverse plane example of forefoot adduction with, 6)1st metatarsal head length standardized to other foot types in Figs 5,6 and 7.

Diagram 4) Fig 5 Transverse plane example of forefoot abduction with, 7)1st metatarsal length.

Diagram 5) Fig 6 Transverse plane example of; mild HAV(bunion) with, 8) a 1st metatarsal head length.

Diagram 6) Fig 7 Transverse plane example of; severe HAV (bunion) (with a Taylor's bunion abduction of 5th toe) with, 9) 1st metatarsal head length.

Diagram 7) Fig 8 Overlay of Figs 4-7 with heel apex and 1st metatarsal head points in focus at same points viewed in transverse plane of different foot types.

4) heel apex, 5) weight bearing center of 15t metatarsal head.

12) & 13), shows the variance in position of weight bearing center of 5th metatarsal head between Figs 4-7.

I 3a) shows variance in position of styloid (base of 5th,metatarsal).

14) shows variance in position of talo-navicular-medial cuneiform area.

Diagrams 8) Fig 9 Forefoot, 1 st ray or 5th ray (and heel) camber variance requiring compensation by moldable low temperature thermoplastic insole under layer.

Fig 10 Arch height variance requiring compensation by moldable low temperature thermoplastic insole under layer.

Diagram 9) Fig 11 Outline of 38), rigid high temperature thermoplastic foot component in transverse plane, showing 15), recess point in surrounding Outer bracing Component where vertical height of Outer Component is same as foot component to allow overhanging, projection of styloid process (with severe HAy).

16) Sufficient space to accommodate abductus/rectus foot-type/talo-navicular-medial cuneiform area and flat foot (with or without compression of insole layer under arch area).

Diagrams 10) Fig 12a Clinical examples of, 17)tibial varum, with, 18) protruding lateral malleolus and 19) neutral tibial varum and high midtarsal oblique axis 20) protruding medial malleolus taken from cast studies from 2 subjects, with concordant 1st metatarsal head/heel lengths viewed as cross section in frontal plane.

Where 20a) shows the generic midline between both varum and valgum limbs, encompassing both, outlining the frontal plane line of the rigid leg component and Outer component.

Fig 1 2b Transverse plane cross-section at mid/upper calf with, 21), tibial varum, 22), average tibial varum (around 3.5 degrees) and 23) neutral sample, with 24) upper wings of high temperature thermoplastic leg component.

Fig 12c&d Demonstrate how upper portion of leg component rolls into mild adjustment of tibial varum (with overlapping retentive formable panels and strapping omitted from diagrams).

Diagram 11) Fig 13 Outline of 37) prototype inner leg component in frontal plane from behind with, 25) reflected side leaves.

Diagrams 12) Fig 14 Sagittal side view leg component, with 25) reflected side leaves skirting around 29) worst case fibular malleolus and 28) slightly higher and projecting more forward, skirting around worst-case medial malleolus.

Also, 30)10w temperature thermoplastic sleeve retaining panel holes to receive medium -high temperature retaining togs/hooks or metal popper studs/rivets.

Area 33a) shown on formable attached leg panel selected to increase height of cast above rigid leg component can be resculpted / "windowed" (thermoplastic/cushioning material removed) from within outer retaining belt over peroneal nerve under head of fibula (commonly entrapped in "below the knee casts"). Area 33b), is cut away from rigid leg component on lateral side, to avoid pressure below head of fibula (superficial point of peroneal nerve) in the case of a short leg.

57a represents flat area that adjoins to inner facet of 0' shaped area.

Fig 15 Transverse view above ankle area 32), showing 25), reflected leaves.

Diagram 13 Fig 16 Outline of medial side of bracing component and "rocker sole", with 35), D' shaped area around critical stress node during propulsion (near parallel with similar area on opposite side of bracing component and perpendicular to the Rocker sole axis.

Diagram 14 Fig 17 Outline of lateral side of" outer bracing component and Rocker sole", with 15) styloid recess and 35) D' shaped area around critical stress node during propulsion (near parallel with similar area on opposite side of bracing component and perpendicular to the Rocker sole attached outer sole axis of propulsion.

Diagram 15 Fig 18 Sketch of, 37), leg and 38), foot components adjoining at common seam and 37a), points of bisection within inner edge of D' shaped areas.

Diagram 16 Fig 19 Outline of shape of high temp thermoplastic sheet area (with or without composite infill) needed to vacuum form Outer Component, where 40), shows overlapping portions at back of Outer Componment.

Diagram 17 Fig 20 Transverse cross-section of 41), Outer Component with 38) overlying foot plate and 42) indications of underlying corrugation, where 43) and 44) support weight of/contact foot plate at forefoot and heel respectively.

Spaces 45), show gaps between foot component and Outer Component behind heel, providing "tubular like beam-age" to strengthen the device.

Diagram 18 Fig 21 Transverse cross-section of 41), showing 15), recess for styloid process descending down to level of footplate.

Diagram 19 Fig 22a Sagittal plane view of medial side of 38), footplate component.

Fig 22b Sagittal plane outline of lateral side of 38), footplate component.

Showing 56& 57), flat areas abutting inner portions of D' shaped areas.

Diagram 20 Fig 23a Back frontal view of Outer Component 41) (not to scale) with 46) at top of component and 44), space between contra lateral corrugations under heel apex portion around cast.

Fig 23 b Oblique under view of Outer Component with 43), 44) and 46).

Diagram 21 Fig 24 Earlier sketch of device 49), showing 47) "x" degrees ankle dorsiflexion and 48) showing "X" degrees toe dorsiflexion. Both enabling lower heel/sole height while allowing toe clearance during gait while helping to enable 47a) the ten degrees ankle dorsiflexion required to facilitate toe clearance during gait cycle.

49a shows line of Rocker sole.

Diagrams 22 and 23 I Figs 24 and 26 show a transverse Plane outlines of a pneumatic cast walker, medium and large sizes respectively.

Diagram 24 Fig 27 shows an option of attaching side panels to foot component seen in a frontal plane cross section through 1st to 5th metatarsal head area, to enable lateral compensation for fore-foot width parameters, with 50), central insole component, 51), holes in foot component to take hooks 52), with medial and lateral retaining flaps 53)&54) respectively.

Diagram 25 Fig 28) with 55) retaining screw or (detachable popper rivet), 56) cushioning layer, 57) movement allowance for foot width difference at ball of foot, 58) retaining buckle 59) Velcro fastening either sides of strap, 60) frontal plane view of upper sole layer, 61) pegs retaining 60) into 41), 62) lower optional rubber sole layer, 63) lower sole retaining pegs to upper sole layer, 64) retaining belt, 65) outer retaining fabric.

Fig 29 with 66) staggered low temperature thermoplastic mesh or solid sheet, 67) optional high insole and medial side foot panel for high arch and varus limb type, 68) retaining pegs between high temperature thermoplastic components.

Diagram 26 Fig 1 2e shows 17), varum type limb in frontal plane against 20a), border of leg component and Outer Component.

Diagram 27 Fig 12f shows neutral or valgum type limb against leg component and Outer Component periphery in frontal plane.

Diagram 28 Fig 30 shows 35), D' shaped area, 25), reflected portion of leg component against 36) outer bracing line of Outer Component. to

Diagram 29 Fig 31 reveals 69), one of two contra-lateral leg formable leg panels made of low temperature thermoplastic or polyethylene/polypropylene with surrounding retaining fabric to fasten into rivets etc at 30), holes or female partners to popper rivets, where 70), cleaves to ankle topography and overlies margin of two foot side panels, dorsum of foot and opposing leg panel via 72), gap in panel to prevent rucking of panel when formed/ molded over change in directional contour from leg to dorsum of foot.

71), upper retaining leg panel then overlies margin of 70), and its contra-lateral panel.

Diagrams 30 Fig 32-36 shows frontal plane cross section of forefoot area with the option of attaching 54), side foot retaining panel to foot component and Outer Component by 74&75), popper rivets, through 76), retaining side panel strap stitched at point 72) to 54) s' outer fabric and held to popper rivets through 77), holes in 76).

Said popper rivet is prevented from coming out by 79), retaining hook held fast to Outer Component through 80), hole in Outer Component.

73), recesses in foot component keep height of insole and side panels linear.

54a shows outer fabric sleeve to panel.

Diagrams 31 Figs 37-41 show holes and popper rivet female parts on side of rigid cast assembly, with 81), external retaining belts, 79), retaining hook and 82&83), Hook and Loop strap and buckle.

85) shows recess in Outer Component to conform to foot component contours.

Diagram 32 Fig 42&43 shows transverse oblique view of 87), insole component, where 86&85) margins at toe area and fore vamp area overlap and tuck under 88), sagittal cross-section of overlying side panels.

[87a shows toes on top of insole].

Claims (1)

1. Patent Claims Claimi] An ergonomic removable below the knee cast for

   use on a patient, said cast having one or two support members either side of heel and skirting slightly behind ankle area, comprising one or a plurality of rigid components, supporting the under surface of the foot, containing the back surface of the leg, sweeping behind ankle, selected for a specific contra-lateral limb from several sizes according to foot length, body weight, head height and heel width, while enabling further attachment of a plurality of formable panels that are directly contoured and adjustable to patients' forefoot width, ankle, bony and weight bearing lower limb contours, all said components inter-joined by fastening means while also providing a Rocker sole.

   Claim 2] A novel removable total contact cast as claimed in claim 1, wherein the inner foot sole and leg components connect to the outer component via appropriate clasps, rivets or strong bonding adhesive, adjoining at center of base of heel, and center of fore foot portion due to raised portions of corrugation in foot portion of outer component and also at sides at or just below straight edge of two D' shaped areas, the inner leg component attached in a similar way to lower foot component behind central heel area and about a 3 way up the leg where leg and outer component touch around the top center of the outer component while abutting up to the foot component margin through heel.

   Claim 3] A novel removable total contact cast as claimed in claims I and 2, wherein the two tubular support members both have near parallel flat D' shaped areas perpendicular to ground and axis of Rocker sole resisting against high propulsive forces during "toe off' phase of gait, with the two 0' shaped areas present on the outer bracing component, connecting and adjoining to two inner, foot and leg components at their respective margins to form the two crescent shaped tubular members.

   Claim 4] A novel removable total contact cast as claimed in claim 1, 2 and 3, wherein the two tubular members contain the space between the two flat D' shaped areas of the outer component, its two under corrugations sweeping behind the heel area and extending forward forming the Rocker sole and between the undersurface of the foot plate and behind the heel area of the leg component.

   Claim 5] A novel cast walker as claimed above, wherein the D' shaped flat area on the outer fibular side of the outer component has a smaller surface area than the medial side of the tibia side.

   Claim 6] A cast as claimed above, wherein the outer component also provides a platform for foot sole component due to an upper corrugation at heel and forefoot, while two lower corrugations provide form of Rocker sole, also enabling outer bracing for leg component, the outer upper fore nm of the outer component also supporting the fore portion of rigid foot plate.

   Claim 7] A cast as claimed above, wherein the rigid bracing outer component presents 2 near parallel flat D' shaped areas that are ergonomic to a specific contra lateral limb, so that the inner tibial malleolus or ankle bone D' area is more projected forward and upwards than the outer fibular malleolus in the sagittal plane and both D' areas skirt behind both sides of ankle providing sagittal beam-age perpendicular to axis of propulsion at Rocker sole during toe of stage of gait.

   Claim 8] A cast as claimed above, wherein a Rocker sole is present at the base of the outer component comprised of two near parallel corrugations sweeping upwards from ground at said axis or bar, presenting a curvature under the sole to enable near normal gait prior to and during toe clearance during the "toe off" stage of the gait cycle, where the height of the heel and sole is reduced by elevation of forefoot to heel by three or so degrees ankle dorsiflexion at upper supporting fore portion of outer component under foot plate, further elevation of toes occurring through the low temperature thermoplastic attached portion upon the forefoot area of the rigid foot plate allows toe clearance while reducing height under heel and sole during the gait cycle for this rigid immobilizing cast assembly.

   Claim 9] A novel removable total contact cast as claimed above, wherein the two near parallel corrugations on the outer Component track from heel to forefoot and join in the middle forming a H' like shape when viewed from under-neigh sole portion, helping to reinforce structural integnty of outer component under various dynamic forces occurring during gait cycle, the two upright lines of the this H' like shape form the Rocker sole and the connecting line or adjoining corrugation between the two upright lines, the two spaces above and below the connecting line are recessed and enable contact with the mid portions of the forefoot and heel areas of the footplate component, a further space continuing and sweeping behind central heel recess affords contact with the lower portion of the rigid high temperature leg component.

   Claim 10] A removable below the knee total contact cast as claimed above, that could contain a materials recipe of high and low temperature thermoplastic components, where the semi rigid moveable low temperature thermoplastic can be defined as being made plastic or formable at 60 degrees Celsius and the stiff rigid high temperature thermoplastic with or without composite fiber infill can be defined as 130 degrees Celsius upwards, further including clasps, hooks, belts, fabric, buckles and such retaining paraphernalia with the option of a strong bonding adhesive between high temperature rigid components.

   Claim 11] A cast as claimed above, wherein the leg and foot low temperature panels or attached flaps could be replaced with water activated polypropylene and polyethylene mesh, with just one single low temperature thermoplastic insole component to conform to the camber and arch height of the foot sole.

   Claim 12] A cast as claimed above, wherein the two under corrugations curve upwards from the mid foot area to the ball of the foot and bring the fulcrum and axis of propulsion during the toe off stage of gait closer to mid foot area, reducing ground reaction force from toe or ball of foot compared to a flat rigid sole. Where the two corrugations raise from the ground level symmetrically providing a linear axis perpendicular to D' shaped areas to outline Rocker sole.

   Claim 13] A removable cast as claimed above, wherein the interconnecting form of the foot

   JL

   and leg components contain the shape of the generic lower limb over specific size margins, and can be selected by knowing the individual patients body weight, head height, foot length and choice of right or left limb, whereby, said components encompass the parameters for a tibial varum or a tibial valgum or neutral type of limb for a given heel/ankle width assessed by knowing individuals above data, skirting behind fibular and tibial malleolii, allowing sufficient space between under and back surface of tibial malleolus and cushioning material to compressed molded sheet or mesh layer of low temperature thermoplastic and retaining fabric against, inner connecting portions of rigid high temperature thermoplastic leg and foot components against straight line of tibial D' area of outer component.

   Claim 14] A novel removable below the knee total contact cast as claimed above, that is adjustable to forefoot width, sole camber, knee height and changes in tibial varum or bowing of tibia and ankle in the frontal plane through compression and lateral drift of low temperature thermoplastic attached panels or flaps.

   Claim 15] A novel removable total contact cast as claimed above, wherein the right or left foot sole component forms the generic shape of the under sole of a right or left foot for a specific foot length and encompasses the parameters of forefoot abductus and adductus for that foot length, the leg component contains the posterior shape of a right or left leg for a specific size range encompassing the parameters of tibial varum and sweeping behind the ankle area, both leg and foot components abutting at a seam from heel apex to below either side ankle areas.

   Claim 16] A novel removable total contact cast as claimed above, wherein the foot plate is streamlined from generic limb data and radiograph studies, to support the center of the 1St metatarsal head and center of the 5th metatarsal head, supporting a wider forefoot or encompassing a narrow foot where the forefoot width can adjust significantly by virtue of thermoplastic moldable thermoplastic flaps / panels being able to reflect in or out laterally above the rigid foot plate and outer component at the 5th metatarsal head, also adjusting to foot type parameters for arch height, while allowing space and clearance for position of styloid or base of the 5th metatarsal, enough to encompass different foot types for a given foot length.

   Claim 17] A novel removable total contact cast as claimed above, wherein the components can be selected before a patient enters the hospital or health care casting room by knowing the patients weight, height and foot size.

   Claim 18] A novel removable total contact cast as claimed above, wherein the high and low temperature thermoplastic or polyurethane/polyethylene components can be specifically tailored for an individual patient according to head and associated knee height, ankle/heel width, foot length and limb girth in required limb topography for surface area and dimensions and also component thickness for stress requirements according to body weight and selected from several size options.

   Claim 19] A novel removable total contact cast as claimed above, wherein the knee height can be adjusted by selecting the optimum height of two low temperature thermoplastic leg components, whereby, the taller corresponding low temperature thermoplastic leg components extend above the height of the rigid thermoplastic leg component to increase surface area containment of leg and better immobilization of lower limb, furthermore, girth requirements of attached formable panels can also be tailored to specific requirements by knowing a patients weight, height and foot size.

   Claim 20] A novel removable total contact cast as claimed above, wherein the rigid assembly with thermo formable and or other such as water activated polyurethane and polyester mesh attachments to inner periphery of foot sides, ankle and leg regions of assembled cast enable each individual lower limbs bony surface topography and weight bearing sole to be conformed to, redistributing pressure evenly around said areas.

   Claim 21] A cast as claimed above, wherein the low temperature thermo formable retaining flap components include a plurality of upper leg and lower foot components attached to the outer edges of the rigid cast components with retaining fabric/hooks/straps/clasps/buckles etc, whereby layers of low temperature thermoplastic solid flat sheet or mesh, precut to fit, can be inserted into sleeves or pockets within retaining fabric, that can be immersed in a hot water bath or tray before clipping or hooking to the sides of rigid components, furthermore, the amount of layers can be changed according to the topographical requirements of the individual.

   Claim 22] A cast as claimed above, wherein the streamlined ergonomics of the components dimensions result from mid-lining the dimensions of the rigid high temperature thermoplastic components between varum and or neutral types of leg, ankle and heel in the frontal plane viewing and considering both case scenarios in the frontal plane, while also accommodating various foot types, allowing for expansion of foot width by the low temperature thermoplastic retaining flap held fast to rigid foot and outer component.

   Claim 23] A cast as claimed above, wherein for a heavier body weight and wider associated heel width, the required rigid outer component can be made thicker and stronger, helping to streamline the weight and robustness of the cast to its stress requirements.

   Claim 24] A cast as claimed above, wherein peroneal nerve entrapment is avoided by removing pressure from below the head of the fibula in the case scenario of a short person and associated short leg for given foot size/length and associated component selection, via a notch within the outer, upper wing of the rigid leg component redistributing pressure off this area.

   Claim 26] A cast as claimed above, wherein the back vertical portion of the outer component has shallow corrugations of a few millimeters or so, continuing from under heel to increase surface area of D' shaped areas, which taper off up back of vertical portion of outer component, with the top rim of vertical portion of outer component curving around to cradle back of leg component.

   Claim 27] A cast as claimed above, wherein the semi rigid low temperature thermoplastic flaps or panels are held fast to limb and rigid high temperature thermoplastic assembly by external straps fastened to outer component and leg component.

   Claim 28] A cast as claimed above, wherein the lower portions either side of the leg component above the ankle area reflect back slightly, enabling contact to the outer component either side above the D' shaped areas.