Patent Publication Number: US-2023134968-A1

Title: Ambulatory protective device

Description:
FIELD 
     This disclosure relates to lower extremity walkers and, in particular, to walkers and other ambulatory protective devices for use with diabetic foot wounds. 
     BACKGROUND 
     Ambulatory protective devices, such as CAM walkers, that is, “Controlled Ankle Movement” walkers, are available in a variety of shapes and sizes. Among their purposes, such leg walkers immobilize the ankle joint, protect portions of the lower extremity, or otherwise treat or address a variety of conditions of the lower extremity. 
     While certain CAM walkers may include panels or portions to increase or decrease the leg height of such walkers, such designs suffer from various drawbacks and disadvantages. For example, adjustable-height walkers are often complex to manipulate or otherwise not suited to various lower extremity treatment protocols, such as when lower extremities are casted. 
     Devices which may be associated for use with rigid or semi-rigid casted lower extremities may also suffer from various drawbacks and disadvantages, including their limited application and disadvantageous offloading or other therapeutic characteristics. 
     Due to the limited adaptability and other drawbacks of CAM walkers of the current art, medical practitioners, hospitals, and other care centers are often required to “double up” on CAM walkers, or otherwise stock and make use of discreet CAM walkers for different treatment phases or lower extremity conditions, thereby causing excess inventory and wasteful inefficiency in the healthcare system in general, and to patients and care providers in particular. 
     Ambulatory protective devices, such as CAM walkers, generally include footbeds upon which the wearer’s foot is placed. The footbeds of many ambulatory protective devices are often little more than a padded topcover and thus often include little to no structure characterized as an insole, such ambulatory protective devices instead relying on excessive padding or other devices to protect the user’s foot received on such footbed. 
     In the case of footbeds formed into or associated with more supportive structures, and thus more characterizable as insoles in the current art, such insoles suffer from various drawbacks and disadvantages. For example, while cushioning insoles, insoles with firmer portions, or insoles with viscoelastic or gel portions might be known in retail or consumer applications, often associated with sports activities for the average wearer, such comfort insoles of the current art, regardless of shape, differing materials, or contours, do not adequately address specific needs of a wearer of an ambulatory protective device, such as a protective shoe, protective boot, CAM walker, other braces, and casts. Such ambulatory protective devices are generally worn when the user’s foot has an injury, such as a foot wound or foot ulcer, or is suffering from pain or medical condition, such as neuropathy, such conditions often associated with those with diabetic conditions. 
     Accordingly, to the extent they have insoles of the current art, ambulatory protective devices, when worn by a diabetic or other user with a foot wound, do not adequately relieve associated medical foot conditions, do not sufficiently protect vulnerable feet which may have, or are susceptible to, the foregoing medical conditions, nor do devices of the current art promote effective healing of foot wounds, ulcers, or other conditions. These shortcomings of insoles and their associated ambulatory protective footwear are especially prevalent, as alluded to above, in devices prescribed or adapted for use in treating and protecting the feet of diabetics. This state of the art has resulted in a statistic that 24% of all diabetic foot wounds lead to limb amputation within 6-18 months of initial evaluation. 
     In view of the foregoing, despite the availability of polymeric materials with different physical properties, the insoles of ambulatory protective footwear of the current art have not been designed to adequately address the needs for protecting and healing the feet of diabetics during ambulation, and thus lessening the risk of limb amputation. 
     Accordingly, it would be desirable to address the foregoing drawbacks and disadvantages with an improved ambulatory protective device or CAM walker. 
     SUMMARY 
     In one possible implementation, according to the present disclosure, an ambulatory protective device is configured to be worn on a person’s foot who has a foot condition, such as a diabetic foot condition. The ambulatory protective device is generally configured to reduce forces on the foot condition so as to reduce pain, promote healing, and accomplish other therapeutic benefits. So, for example, the ambulatory protective device may include an insole which is configured so that, when the ambulatory protective device is worn during ambulation by the person, the average contact pressure in the heel area and the forefoot area on the foot wearing the device is reduced from that otherwise present without the insole of the present disclosure. The insole extends medially, laterally, distally, and proximately, so as to define a footbed within the ambulatory protective device. 
     In certain implementations, the ambulatory protective device may have a frame which extends from the footbed. Such frame may include a posterior and an anterior portion, as well as distal and proximal ends which are configured to engage corresponding portions of the foot and calf of the person wearing the device. The insole in such implementations may include a top layer, a middle layer located under the top layer, and a bottom layer located under the middle layer. The middle layer has a stratum in which open trays are formed. These open trays, in certain implementations, are located in the forefoot and heel areas, respectively, so as to underly the forefoot and heel of the person when the device is being worn. 
     The middle layer likewise includes inserts which consist essentially of viscoelastic material or gel, and these inserts are received in the above-mentioned open trays. While the inserts may consist essentially of viscoelastic material, the stratum of the middle layer consists essentially of polymeric foam material. The compression set and rebound values associated with the polymeric foam material are sufficiently higher than the compressions set and rebound values associated with the viscoelastic inserts. As such, the insole, when worn during ambulation, reduces the average contact pressure in the heel area and the forefoot area, up to 30% reduction in certain implementations, as compared to ambulation occurring without the insole of such device. 
     In further implementations, the compression set value of the polymeric foam material may be at least 200% higher than that of the viscoelastic insert, and the rebound value of the polymeric foam material may be at least 800% higher than the rebound value of the viscoelastic insert. 
     In further implementations, the above-mentioned open trays are bounded by circumferential walls which define the sides of the open trays, and the trays are further bounded above and below by overlying and underlying planar polymeric foam portions, which thus form the tops and bottoms of the trays. The inserts are configured so that their outer edges are spaced from their circumferential side walls and thereby form circumferential gaps between the inserts and the sidewalls of the stratum. These circumferential gaps have dimensions which are sufficient so that the viscoelastic inserts and the opposing circumferential walls of the stratum remain separated from each other even when the insole is subj ected to the predetermined maximum weight normally associated with the person wearing the device. As such, the physical properties associated with the viscoelastic insert, such as reducing contact pressure on the forefoot and heel areas, are not affected by any contact which may otherwise arise between opposing portions of the outer edges of the viscoelastic inserts and the sides of the trays. 
     In still other implementations, a CAM walker or other ambulatory protective device may include a frame which controls ankle movement of the lower extremity. The frame, when worn, has a distal frame end at or near the foot and a proximal frame end generally above the ankle, each frame end adapted to operatively engage, whether directly or indirectly, portions of the foot and calf, respectively, when the frame is being worn. The CAM walker may include a collar assembly which is selectively fittable to, and manually separable from, the proximal end of the frame. As such, a medical practitioner, to address therapeutic needs, for example, may take actions with the CAM walker of this disclosure to fit the collar assembly to the proximal end of the frame; may forego attachment of the collar to the frame; or, if the collar were previously attached, may separate such collar from the frame, such as in response to other therapeutic needs. 
     In one variation of the implementations disclosed herein, the CAM walker frame has a foot bed with lateral and medial sides. The frame of the CAM walker, in turn, has corresponding lateral and medial frame elements which partially define a frame circumference and a corresponding frame volume, the circumference and volume being sufficient so that they are capable of receiving not only an ankle and corresponding lower extremity therein, but such ankle and lower extremity therein when wearing the other brace device received in the CAM walker. 
     In implementations of the present disclosure, the insole may be configured to provide greater protection, force redistribution, force reduction, or other therapeutic benefits to wearers of a variety of ambulatory protective footwear, equipped with an insole having trays with viscoelastic inserts received therein in a spaced manner. Such insole may be formed as a multilayer, force reducing insole, that and its construction may be considered to not only utilize the mechanical properties of different materials, but combine such materials in a fashion such that the mechanical force reduction and therapeutic benefits resulting are greater than the mechanical abilities of each of the materials alone. 
     Although this disclosure applies to ambulatory protective footwear for adding protection to a user’s foot in any suitable application, this disclosure may find particular application to patients with medically diagnosed foot pain, foot wounds, or other foot injuries requiring the use of a protective boot, such as patients with diabetic foot conditions. 
     In certain implementations, the insole of the instant disclosure may be of four layer construction and is designed to interface with the human foot for use within, or affixed to, shoes, boots, braces, casts, or other types of footwear. The insole described herein in one implementation is part of ambulatory protective footwear, such as a protective boot. 
     In further implementations, the four layers, or strata, may comprise materials of different resilience, compression, and related characteristics. Significantly, the third such stratum is constructed from foam having open or closed cells of medium density and durometer, and such third stratum is configured to have open chambers or trays formed therein that are located directly under the anatomical areas of the user’s heel and forefoot. 
     In such implementations, the openings of such trays are sized to receive viscoelastic inserts or pods therein, such inserts or pods having a lower durometer preferably than the adjacent portions comprising the third layer of material, making such viscoelastic inserts less resilient, and more compressible than the adjacent portions of the third layer. These inserts or pods are spaced from opposing walls of the trays into which they have been inserted. The spacing is selected to allow for the substantial or full expansion and deformity of such pods or inserts without the inserts impinging upon or interfering with the opposing material of the tray. Such pods or inserts additionally are not bonded to the adjacent upper or lower layers located on either side of the third layer, allowing for such pods or inserts to ride freely within each of such trays. 
     In the preferred implementation, each of the second, third, and fourth layers of such insole have a thickness of approximately 7 mm in the uncompressed state, such that, with a relatively thin woven top cover as the first layer, the total thickness of the inventive force-reducing insole is slightly greater than 21 mm, that is, 4 or 5 mm short of an inch. As such, the insole may be set into an insole-receiving aperture or other sole structure, or may be otherwise integrated into the sole of the footwear, either permanently or selectively removable therefrom. 
     The lowermost such layer is designed in the preferred implementation to be constructed of an impact absorbing polymeric material, such as PORON XRD, or material which may be otherwise described as made of a high compression resistant material, either open or closed cell foam, plastic, or rubber. The material of this layer provides a significant reduction in force, as well as adding structure to the insole and allowing for an interface with the devices in which the inventive insole may be used, whether shoes, boots, braces, or casts. For this reason, such bottom layer is useable either above and adjacent to an outsole, or such bottom layer itself may be formed to have a bottom surface suitable for contacting the ground and thus serve as an outsole. 
     Such top layer of the force-reducing insole in the preferred implementation is designed to be constructed of a cover material that is friction-reducing, water resistant, and antimicrobial, typically a woven material that can be made of several different fabrics, natural materials, or plastic. As such, the top layer is designed to be in contact with the foot, such that overlying additional layers could be inserted by a user if desired, but are not required. 
     Another implementation relating to the multi-layered insole disclosed herein is based in part on teachings from the applicant’s earlier U.S. Pat. 11,006,693 entitled Articles of Footwear for Inhibiting and Treating Injuries, specifically the implementation of the insole of the present disclosure into a protective boot as described in said Patent. 
     Other objects, features and advantages of this disclosure will become apparent from consideration of the following detailed description and from the accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of one possible implementation of a walker, such as a CAM walker, having a collar assembly which is removably attached to an underlying frame; 
         FIG.  2    is a perspective view of the walker of  FIG.  1   , with the collar assembly removably secured thereto; 
         FIG.  3    is a side elevational view of a portion of the collar assembly of  FIGS.  1 - 2   ; 
         FIG.  4    is a side elevational view of the portion of the collar assembly shown in  FIG.  3   ; 
         FIG.  5    is a rear elevational view of the portion of the collar assembly shown in  FIGS.  3  and  4   ; 
         FIG.  6    is a top plan view of the portion of the collar assembly shown in  FIGS.  3 - 5   ; 
         FIG.  7    is a bottom plan view of the portion of the collar assembly shown in  FIGS.  3 - 6   ; 
         FIG.  8    is a sectional view taken along reference line 8-8 of  FIG.  2   ; 
         FIG.  9    is a sectional view taken along reference line 9-9 shown in  FIG.  2   ; 
         FIG.  10    is a perspective view of another possible implementation of this disclosure; 
         FIG.  11    is an exploded perspective view of still another possible implementation of this disclosure; 
         FIG.  12    is a rear elevational view of the implementation of  FIG.  11   ; 
         FIG.  13    is a cross-sectional view of the implementation of  FIGS.  11 - 12   , taken along line 13-13 of  FIG.  12   ; 
         FIG.  14    is a cross-sectional view of the implementation of  FIGS.  11 - 13   , taken along line 14-14 of  FIG.  12   ; 
         FIG.  15    is a sectional side view, showing portions of another implementation of the ambulatory protective device of  FIGS.  11 - 14   , taken along line  15 - 15  of  FIG.  12   ; 
         FIG.  16    is a front sectional view of the ambulatory protective device of  FIGS.  11 - 15   , taken along line 16-16 of  FIG.  15   ; 
         FIG.  17    is an exploded perspective view of one implementation of the protective, force-reducing insole suitable for use with an ambulatory protective device, such as that shown in  FIGS.  11 - 16   ; 
         FIG.  18    is a sectional, side view of the insole of  FIG.  17    taken along line 19-19 of  FIG.  18   ; 
         FIG.  19    is a top view of the insole of  FIGS.  17 - 18   ; 
         FIG.  20    is a table showing physical properties of a material suitable for use with the protective, force-reducing insole of the current disclosure; 
         FIG.  21    is a table of physical properties of another material suitable for use with a protective, force-reducing insole of the current disclosure; 
         FIG.  22    is another table of physical properties of another material suitable for use with a protective, force-reducing insole of the current disclosure; 
         FIG.  23    is a bar graph showing force-reducing characteristics of ambulatory protective devices having the protective, force-reducing insole of the present disclosure, compared to ambulatory protective devices without such protective, force-reducing insole; and 
         FIG.  24    is another bar graph showing force-reducing characteristics of an ambulatory protective device equipped with a protective, force-reducing insole of the present disclosure, compared to ambulatory protective devices without such protective, force-reducing insole. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the terms ambulatory protective device, CAM walker, and walker may be used interchangeably with each other and, accordingly, each and any of such terms shall broadly mean any number of protective boots, walkers, or other lower extremity footwear for controlling or limiting relative movements of a lower extremity, protecting or isolating such lower extremity, or achieving other therapeutic goals related to the lower extremity. The terms distal and proximal, anterior and posterior, medial and lateral, shall be in reference to a standing individual. 
     Referring more particularly to the drawings,  FIG.  1    shows a perspective view of a walker  21  which is manually fittable to and removable from a lower extremity to be treated. In the illustrated embodiment, walker  21  is in the form of a CAM walker configured so as to be suitable for use with a brace device being worn by a patient, such as a cast, on his or her lower extremity. To that end, walker  21  includes a frame  23  which is not only adapted to control ankle movement of a lower extremity received thereon, but is also sized and shaped to receive both the patient’s ankle and the associated brace device therein. To that end, frame  23  includes frame elements  25  which at least partially define a frame circumference  27  and a corresponding frame volume  29 . 
     Frame elements  25  may assume a variety of configurations, including, for example, a rigid or resiliently flexible shell  31  having a posterior brace portion  33 , a closure system  35 , including one or more adjustable closure belts  37 , a foot bed  39 , and rigid or semi-rigid struts  41  extending upwardly or proximally (in relation to the wearer) from foot bed  39  on each of the lateral and medial sides of the foot bed. Struts  41  are transversely spaced by a distance α at their upper ends so as to have inner surfaces  43  proximate to opposing surfaces of the brace device (such as a cast) when worn on the lower extremity received in walker  21 . Walker  21  as described herein is adaptable and suitable for use with any number or type of brace devices, whether rigid or semi-rigid casts of plaster, fiberglass, or alternate materials, splints, bandages or other removable bracing, and the like. 
     As such, frame  23  has an upper or proximal end adapted to operatively engage portions of the calf when received therein and a lower or distal end adapted to operatively engage portions of the foot, meaning to contact, directly or indirectly through the brace device, in order to protect, restrain, or otherwise control movement of the lower extremity for desired therapeutic purposes. 
     In the disclosed and illustrated implementation, a collar assembly  45  is configured as subsequently detailed herein, so as to be selectively fittable to, and manually separable from, the proximal end of frame  23 .  FIG.  1    shows collar assembly  45  separated from frame  23 , whereas  FIG.  2    shows collar assembly  45  fitted to such frame  23 . More particularly, collar assembly  45  is removably received on upper ends  49  of struts  41 . Collar assembly  45  includes one or more engagement areas  47  oriented and suitably configured so that when collar assembly  45  has been fitted to upper ends  49  of struts  41 , engagement areas  47  engage an opposing surface of the cast or other brace device received on or into frame  23 . 
     Engagement area  47  may comprise inner surfaces of corresponding engagement members  53 , and such engagement members  53  may assume any number of suitable forms, in the illustrated embodiments shown as paddles having quadrilateral profiles. Engagement members  53  are suitably interconnected or secured relative to each other by one or more adjustable, flexible straps  55  which make up a collar closure system  57  which can be manipulated to open or otherwise transform collar assembly  45  so it can surround the cast or other brace device associated with leg walker  21 , and then adjusted, such as by tightening or shortening straps  55 , thereby transmitting radially inward force on engagement area  47  of engagement members  53 . Closure system  57  and associated straps  55  are oriented and sized so that manual tightening or other similar adjustment may produce sufficient inwardly directed force to substantially maintain the engagement of collar assembly  45  with the opposing portions of the cast during the anticipated gait cycle associated with the lower extremity and thereby impart to the patient all the advantages of such engagement. 
     Referring now to  FIGS.  3 - 7   , one of the engagement members  53  is shown in various plan views and described in further detail. Engagement member  53 , shown as a paddle in the illustrations, has a longitudinal axis A and longitudinally extending connection portion  59  by which engagement member  53  can be removably secured to a corresponding one of struts  41  by longitudinal movement of connection portion  59  relative to strut  41  and its upper end  49 . As best seen in  FIG.  7   , connection portion  59  is formed with inner surfaces defining a slot  61  which extends longitudinally and terminates in a slot opening  63  oriented distally or downwardly and sized to receive a mating portion of upper strut end  49  therein. Slot  61  and upper strut end  49  may be removably secured relative to each other by friction fit; mechanical interlock, such as with tabs or flanges, or press-fit or release mechanisms; fugitive adhesives, or hooks and eyes (VELCRO). Mating portions between collar assembly  45  and frame  23  may likewise take on different forms than slot  61  and upper strut end  49 , including different configurations of male/female attachment or still other removable attachment structures. 
     Slits  65  extend through inner and outer surfaces of engagement member  53  so that corresponding straps  55  may be threadably received therethrough for operation as closure system  57  ( FIGS.  1 ,  2   ). 
     Engagement member  53  includes opposite inner and outer surfaces, inner surface  67  being substantially planar but having formed thereon a pattern of protrusions  69  extending from inner surface  67 , that is, away from the plane of such surface. When collar assembly  45  is secured to frame  23 , protrusions  69  extend inwardly from the plan of inner surface  67  toward the corresponding opposing surface area of the brace device. Protrusions  69  are in the form of elongated elements or ribs  73  as illustrated, but may assume any number of shapes and patterns, including a roughed or stippled surface, a pattern of X’s, O’s, or the like, or any number of protrusions which terminate in surfaces having sufficiently narrow profiles so as to engage the opposing surface of the cast or other brace device corresponding to the upper surfaces of such protrusions  69 . The combination of the area of inner surface  67  and geometries of the pattern of protrusions  69  are tuned or selected to substantially inhibit slippage of frame  23  relative to brace device received therein during ambulatory or other anticipated activity. 
     Inner surfaces  67  of engagement members  53  also include respective, arcuate, inner surfaces  71  which extend on such inner surface  69  to terminate in anterior and posterior longitudinal side edges and have concave arc β of less than 45°, and preferably have an arc extending between 10° and 30°. Extending from the longitudinal side edges of the arcuate surfaces  71  are engagement wings  75 . Engagement wings  75  extend transversely, that is anteriorly and posteriorly, respectively, from the side edges of arcuate inner surface  71  and are formed of resiliently flexible material, with a resilient flexibility. Portions of straps  55  overlie or run along outer surface portions of engagement wings  75  so that, in response to straps  55  being adjusted or otherwise tightened and transmitting radially inward force, an inward force on outer surfaces of engagement wings  75 , in turn, urges engagement wings  75  against the opposing surface of the brace device adjacent to collar assembly  45 . 
     In view of the foregoing described structure, inner surfaces  67 , including arcuate inner surface  71 , inner surfaces of engagement wings  75 , as well as inner surfaces of straps  55  ( FIGS.  1 ,  2   ), together form the previously discussed engagement area  47 . In this way, engagement members  53  interconnected by one or more of the straps  55  define a substantially cylindrical volume, which is not only sized to circumferentially receive the brace device therein, but is capable of transmitting radially inward force to the engagement area over substantially all of the 360 degrees of the circumference defined by the cylindrical engagement area  47 . 
     The protrusions  29  which are urged by tightening of straps  55  radially inwardly are selected and configured so as to be suitable for engagement of rigid or semi-rigid cast material or other corresponding surfaces of the brace device received in CAM walker  21 , and generally not suitable for direct contact with the skin of lower extremity received therein. By suitable engagement of the brace device by engagement area  47 , engagement members  53  extend or lengthen the lever arm created between the distal end of CAM walker  21  and its proximal end. Since the frame  23  is configured to reduce force on the foot during gait as a function of the lever arm of CAM walker  21 , the extension of the lever arm by addition of collar assembly  45  to frame  23  further reduces force on the plantar surface of the foot when received in CAM walker  21 . 
     Operations of the walkers  21  described herein are apparent from the foregoing description. A medical practitioner or other user of walker  21  may choose to fit collar assembly  45  to frame  23  in order to achieve certain therapeutic goals. A lower extremity bearing a cast or other brace device is received in walker  21  within the volume defined by frame  23  and the circumferential volume defined by collar assembly  45 . Suitable adjustment of one or more straps  55  or other comparable collar closure system caused inner surfaces of collar assembly  45  to define an engagement area  47 . Such engagement area  47  is brought into engagement, either directly or indirectly with the brace device to help accomplish the desired therapeutic goal for the lower extremity received in the brace device, one such goal being to substantially inhibit movement of the casted lower extremity relative to walker  21 . 
     In response to other therapeutic needs, CAM walker  21  may be used without collar assembly  45  received thereon, or after having removed such collar assembly  45  therefrom. In such cases, struts  41  and frame  23  may be suitably configured or structured so as to define a volume suitable for receiving a lower extremity without a cast or brace device therein. Suitable padding or other soft goods may be associated with frame  23  so that the volume of frame  23  is adapted to receive a lower extremity without a cast therein. As such, a treatment facility may simplify inventory and associated costs by having a frame  23  suitable for use both with non-casted lower extremities, without collar assembly  45  associated therewith, and with casted lower extremities, in which case collar assembly  45  would be fitted to frame  23 . 
     In addition to the advantages apparent from the foregoing description, fixing the proximal portion of CAM walker  21  by means of engagement area  47  of collar assembly  45  allows the proximal portion of CAM walker  21  and the cast itself to move together in more unified movements during the gait cycle or other activities, limiting relative anterior and posterior movement of the cast relative to walker  21 , having a positive effect on the gait pattern of the wearer to decrease undesirable forces on the foot, ankle, and lower leg which would otherwise interfere with therapeutic goals. 
     As a further advantage, the engagement member  53  enhances the offloading characteristics of leg walker  21 , that is, reduces the force experienced on portions being treated by the cast on the lower extremity. As such, the combination of the collar assembly  45  and the frame  23  itself create increased mechanical support compared to either the cast itself, or a standard CAM walker. 
     The increase in lever arm by the collar assembly  45  along with underlying cast also serves to alter the wearer’s gait to a more steppage style, thus distributing force over a larger contact surface area on the plantar surface of the foot. In a related manner, the alteration of gait limits speed and strain rate experienced by the foot and results in engagement of larger thigh muscles to advance the lower leg in gait and control the swing phase speed, thereby decreasing impact of the foot against the ground by virtue of engagement of the cast by collar assembly  45 . 
     In one suitable implementation, foot bed  39  has an outer length (posterior to anterior) overall averaging about 315 mm as an outer dimension, and a medial-to-lateral outer dimension of about 140 mm (all such dimensions expressed herein suitably varying for gender, age, and size). Shell  31  of frame  23  extends upwardly or proximally at lateral and medial, respective locations which may be slightly inward of the outer width of foot bed  39 . As such, distance α may range from about 140 mm (about 5 ½ inches) to about 114 mm (about 4 ½ inches). If the lateral and medial frame elements  25  include either struts  41  or semi-rigid or rigid material in shell  31 , then corresponding inner surfaces  43  of struts  41  or shell  31  may define an inner diameter reduced by the thickness of such frame elements  25 , such inner diameter ranging from about 75 mm (about 3 inches) to about 130 mm (about 5 inches). The frame elements  25  spaced as set out above may be used to define a diameter and thus a frame circumference  27  ( FIG.  1   ) ranging from about 240 mm (about 9 ½ inches) to about 400 mm (about 15.7 inches). It will be appreciated that the transverse spacing of inner surfaces of frame elements  25 , whether as part of shell  31  or struts  41  are selected to be spaced proximate to opposing surfaces of brace devices intended to be worn in the lower extremity, and thus the aforementioned dimensions may be further varied to suit particular applications of this disclosure. 
     Proximal end of frame  23 , as well as that of frames  123 ,  223  (described subsequently herein) may extend from a ground plane to corresponding upper proximal edges, such as corresponding to the upper edge of shell  39  below strut end  49  ( FIGS.  1 - 9   ), or upper edges  195  ( FIG.  10   ),  295  ( FIG.  11   ), by a length ranging from about 230 mm (about 9 inches) to about 330 mm (about 13 inches), such lengths including the height of foot bed  39  and stated as an average height, recognizing that upper edge of frame  23  may be suitably contoured in a case of the illustrated embodiment of frame  23 . The lengths of frame  23  may also correspond to the upper ends  49  of struts  41 . Given the previously defined values for frame circumference  27  (and associated radii) and the aforementioned ranges in height of frame  23 , the frame elements  25  define a corresponding frame volume  29  sized to receive both the ankle and the brace device therein, and ranging in volume from to 1,020 cm 3  to 4,380 cm 3   .   
     Such dimensions have been found suitable to remain fixed relative to the underlying cast upon manual adjustment of Velcro-equipped straps having dimensions of between 12 mm and 25 mm (½ to 1 inch) in width. Upper ends  49  of struts  41  extend about 127 mm to 178 mm (about 5 to 7 inches) beyond the upper edge of shell  31 . As such, if engagement at the upper end of shell  31  by uppermost one of straps  37  defines a lever arm for walker  21  having a first length, the addition of collar assembly  45  on the upper ends  49  of struts  41  increases the lever arm by about 127 mm to 178 mm (about 5 to 7 inches), thereby reducing force on the plantar service of the foot when received in walker  21 . Engagement members  53  may be in the form of quadrilateral paddles, as illustrated, extending longitudinally between about 127 mm to 178 mm (5 inches and 7 inches) and transversely between about 100 mm to 152 mm (4 inches and 6 inches). Other sizes and dimensions are likewise suitable, depending on the brace device or other parameters and associated applications of the embodiments herein. 
     Still further variations are contemplated by this disclosure. Thus, for example, although protrusions  29  are described as engaging the opposing surface area of the cast or brace device received in walker  21 , it will be appreciated that engagement area  47  may be equipped with adhesive materials, pneumatic arrangements, such as bladders, other friction inducing materials, hooks-and-eyes (VELCRO), ratchets, and other sorts of adhesive or mechanical affixation devices and materials, suitable for limiting anterior and posterior motion of the proximal end of leg walker  21  relative to the cast received therein. 
     Collar assembly  45  may likewise assume different configurations than the quadrilateral paddles shown here. For example, referring now to  FIG.  10   , another possible implementation has a leg walker  121  with removable collar assembly  145  including a posterior portion  181  formed of suitable resiliently flexible material to constitute or enhance a posterior brace and its associated functions on leg walker  121  and may likewise serve to interconnect lateral and medial paddle portions of engagement area  147  of engagement members  153 . The removable attachment of collar assembly  145  shown in  FIG.  10    may be accomplished in the manner similar to that described with reference to the implementations show in  FIGS.  1 - 9   . In addition, collar assembly  145  and proximal end of frame  123  may be formed so that posterior portion  181  mates with a corresponding posterior brace  191  on frame  123 . In one possible version, posterior portion  181  includes a downwardly oriented slot  193 , which receives an upper edge portion  195  of posterior brace  191  therein. 
     In still another possible implementation, a walker  221  includes a posterior ankle-foot orthosis (“AFO”)  224  and an anterior AFO  226 . Posterior AFO  224  is located to therapeutically engage the posterior portion of the lower extremity by contact through any bracing device therebetween. Anterior AFO  226  is removably secured to anterior locations of frame  223  of walker  221 , so as to therapeutically engage the anterior portion of the extremity, such as the dorsum of the foot. The AFOs  224 ,  226  together form a “clam shell” arrangement. Anterior AFO  226  includes anterior reinforcing stay  228  extending longitudinally, that is, from proximal end  230  of frame  223  to distal end  232  of such frame  223 . 
     Pairs of respective lateral and medial fingers  234  extend transversely from reinforcing stay  228  of anterior AFO  226 , the pairs of fingers  234  located at spaced longitudinal locations on anterior AFO  226 . Fingers  234  are located, sized, and configured to oppose corresponding portions on frame  223  so as to removably secure anterior AFO  226  relative to frame  223 . In this particular implementation, hook-and-eye fasteners are used on opposing surfaces of frame portions  236  and fingers  234 , such as fasteners marketed under the name VELCRO. 
     Walker  221  may include a removable or selectively fittable collar assembly  245 , which operates on principles similar to those discussed with reference to collar assembly  45  and  145 .  FIG.  11    shows collar assembly  245  removed from frame  223 , and  FIGS.  12 - 14    show collar assembly  245  fitted to frame  223 , to engage a brace device received in the frame volume defined by frame  223  and collar as discussed previously. In this implementation, collar closure system  257  makes use of a spacer  258  which may be removably secured, such as by hook-and-eye fasteners at its medial and lateral ends, to opposing medial and lateral portions of collar assembly  245 . 
     Collar assembly  245  includes a posterior portion  281 . Inner surface of posterior portion  281  may function to engage opposing portions of a brace device received therein and thus constitute one of several potential engagement areas  247 . Extending from such posterior portion  281  are lateral and medial engagement members  253 , each such members having corresponding inner surfaces which form additional engagement areas  247  for engaging opposing portions of a brace device received within collar assembly  245 , as discussed previously in reference to the other embodiments. Engagement areas  247  may or may not include inner surface treatments, protrusions, or other features for enhancing engagement with opposing areas of the brace device received therein. 
     Collar assembly  245  in this implementation operatively engages opposing portions of the brace device received therein by urging engagement areas  247  radially inwardly and then securing such engagement areas  247  with suitable inward force, in this case with securing spacer  258 . Securing spacer  258  extends between medial and lateral sides of collar assembly  245  and is removably secured at locations on the outer surface of engagement members  247 . 
     The distal end portions  260  of collar assembly  245  are formed to define a downwardly oriented slot  293  sized and configured to receive therein upper end portion  295  of frame  223 . In this implementation, slot  293  extends substantially around posterior portion  281  as well as the corresponding lower edges of medially and laterally located engagement members  253 . The corresponding proximal end of frame  223  extends by a similar circumferential amount to be substantially received in the slot  293  as described. 
     Slot  293  extends proximally from the distal edge of collar assembly to define a slot depth of any suitable amount for collar assembly  245  to remain fitted to frame  223  and also extend the overall lever arm length of walker  221  if desired for therapeutic purposes. In one possible implementation, collar assembly  245  has an average (longitudinal) length of about 127 mm to 178 mm (5 to 7 inches), and slot  293  extends proximally, inwardly, along such length by amounts ranging from 20% to 70% of the collar assembly length. This results in engagement areas  247  of collar assembly  245  extending proximally beyond the upper (proximal) end  230  by corresponding amounts and extending the length of the lever arm created by walker  221  accordingly. For lever arms of walkers  121 ,  221  having a first length measured from ground plane to the upper, proximal ends  195  ( FIG.  10   ),  295  ( FIGS.  11 - 14   ), the dimensions and attachment of collar assemblies  145 ,  245  may be selected to increase the lever arm to a second length, the second length being longer by 25% to 60%, preferably about 30% to 40%. Other dimensions and configurations of slot  293  and edge portion  295  received therein are likewise suitable. Similarly, locations of slot or other mating portions of collar assembly and frame may be varied, such as by providing edge portion  295  with a slot for receiving an opposing edge (not shown) of the collar assembly  245  therein. 
     In the illustrated implementation, the proximal end of frame  223  has an aperture  296  formed therein which, among other potential functions, may serve as a handle  264  for manipulating walker  221 , such as for fitting frame  223  to the lower extremity or removing it therefrom. Collar assembly  245  includes a tab  298  extending from an inner surface of the collar assembly, such surface located radially inwardly relative to slot  293 . In this way, tab  298  is suitably located, dimensioned and configured to be foldable or moved hingedly so as to be selectively manipulatable around the upper edge of handle  264  formed in frame  223 . Tab  298  further includes suitable fastening elements, such as hook-and-eye fasteners, so that, once manipulated around the upper edge of handle  264 , tab  298  may be removably secured to the outer surface of collar assembly  245 . In this manner, tab  298  restrains collar assembly  245  from proximal or upward movement relative to frame  223 , because upward movement would cause tab  298  and upper edge of handle  264  to engage each other and thus resist proximal or upward movement of collar assembly  245 . 
     Anterior AFO  226 , collar assembly  245 , spacer  258 , and other components of walker  221  may be formed of any suitable resilient, flexible, rigid, or semi-rigid materials, possessing, corresponding reinforcing, resiliency, rigidity, of flexibility characteristics, in accordance with locations of such materials relative to a brace device received therein. Components formed from such materials would likewise have a certain amount of flexibility for purposes of operatively engaging corresponding portions of the lower extremity, either directly or indirectly through the brace device, thereby accomplishing immobilization, offloading, or other therapeutic objectives. As such, certain portions of frame  223  in collar assembly  245  are characterized as “semi-rigid,” that is, resiliently flexible, the amount of resiliency and flexibility being tuned to the particular application. 
       FIG.  15    is a sectional side view, showing portions of the implementation of the ambulatory protective device of  FIGS.  11 - 14   , taken along line  15 - 15  of  FIG.  12   . Walker or ambulatory protective device  221  has a footbed  239  which includes therein an insole  321 . Insole  321  and footbed  239  extend medially, laterally, distally, and proximally to underly a person’s braced, cast, or bandaged footf when ambulatory protective device  221  is worn on the lower extremity. Insole  321  and footbed  239  may be thought of as having a forefoot area  323  located thereon, so as to therapeutically or operatively engage the user’s forefoot, especially its metatarsal heads. Such metatarsal heads may be the location or locations prone to, or having pain, such as metatarsalgia, wounds or ulcers, or other foot conditions, including without limitation those of diabetics. Footbed likewise has a heel area  325  located and extending in footbed  239  and insole  321  toward the proximal side of the plantar region of the foot, thereby underlying the heel of the wearer and, as in the case of the forefoot area  323 , therapeutically or operatively engaging the heel of the wearer, which heel, similarly, may be experiencing or prone to pain, wounds, or other foot conditions. 
     Referring now to  FIGS.  15 - 18   , insole  321  includes a top layer  327 , a middle layer  329  located under top layer  327 , and a bottom layer  331  located under middle layer  329 . 
     Middle layer  329 , in the illustrated implementation, is formed into a stratum  333  having defined therein structures referred to as open trays or chambers  335 . Open trays or chambers  335   are located in forefoot and heel areas  323 ,  325 , respectively. In this implementation, stratum  333  consists essentially of polymeric foam material. 
     Inserts or pods  337  are adapted to be received in open trays or chambers  335 . In this implementation, inserts  337  consist essentially of viscoelastic material, it being understood, however, that other polymeric materials may likewise be suitable. It is likewise understood that encapsulating the viscoelastic material in an outer casing is within the definition of such inserts  337  consisting essentially of viscoelastic material. 
     The viscoelastic material and the polymeric foam material have associated therewith sets of physical properties. In one possible implementation, the viscoelastic material comprises a viscoelastomer or gel having physical properties as set out in  FIG.  20   . Furthermore, in such implementations, the polymeric foam material of stratum  333  may comprise ethylene vinyl acetate (EVA) having the physical properties set out in the table of  FIG.  21   . It should be noted that the physical properties are expressed in the tables of  FIGS.  20  and  21    both in terms of ISO standards as well as ASTM standards, with associated units for each such standards and related methodologies. 
     Referring to the tables of  FIGS.  20  and  21   , the compression set and rebound values associated with the polymeric foam material are higher than the corresponding compression set and rebound values associated with viscoelastic inserts. Those values have been selected to cause insole  321 , when worn during ambulation, to reduce the average contact pressure in both the heel area  325  and forefoot area  323 , when compared to ambulation without insole  321 . 
     The reduction in average contact pressure is further described in the bar graph of  FIG.  23   . As seen in  FIG.  23   , average contact pressure of four anatomical areas has been diagrammed, in this case the forefoot, the heel, the first metatarsal head, and metatarsal heads two through four. The contact pressure for each of these four areas has been averaged over a period of three minutes during testing of ambulatory protective device  221  on a size 12 foot of a two-hundred-pound male. The resulting average contact pressures of ambulatory protective device  221  equipped with insole  321  have been compared to the average contact pressures measured for ambulatory protective devices without insole  321  described herein. More particularly, Device 1 of  FIG.  23    corresponds to ambulatory protective device  221  (with insole  321 ), Device 2 corresponds to ambulatory protective device  221  (with insole  321 ) equipped with collar assembly  245 . In contrast, the higher average contact pressures of the remaining five sets of bars correspond, respectively, to (1) a CAM walker without insole  321  nor collar assembly  247 , (2) a CAM walker without insole  321  but with collar assembly  247 , (3) a protective boot corresponding to a typical CROW Walker, (4) a total contact cast system having cast material in a boot (labeled under the heading “TCC System”), and (5) the cast of item (4) received in ambulatory protective device  221  with insole  321 . 
     In certain implementations, upper layer  327  of insole  321 , as well as stratum  333  of middle layer  329  may be formed of ethylene vinyl acetate (EVA) having physical properties in the ranges shown in  FIG.  21   . In such implementations, as best seen in  FIGS.  17  and  18   , inserts  337  have substantially the same thickness as stratum  333  and thus are coextensive with top and bottom surfaces of middle layer  329  when in an uncompressed state. In the implementation illustrated in  FIGS.  15 - 18    and discussed herein, the properties of the viscoelastomeric material of inserts  337  are such that, as seen in  FIGS.  20  and  21   , the compression set value of the polymeric foam material of stratum  333  may be configured to be 200% or higher than the compression set value of the viscoelastic material of inserts  337 . Furthermore, the rebound value of the polymeric foam material of stratum  333  is configured to be at least 800% higher than the rebound value of the viscoelastic material of inserts  337 . 
     Accordingly, from the above, insole  321  is a configuration of differing materials, having associated physical properties, dimensions, and locations, such that, when subject to contact or impact, that is, compressive force, the force or pressure measured at the time of application of such contact or impact pressure is reduced in the heel area  325  and the forefoot area  323  for those periods of time during the gait cycle when the device  221  with insole  321  on the wearer’s foot contacts the ground. Such periods of time during which the foot contacts the ground are generally referred to as the stance phases of gait cycles. Accordingly, contact or impact pressure reduction from device  221  equipped with insole  321  extends over a period of time corresponding to the stance phase, with corresponding therapeutic benefits to the overlying foot of a wearer. It will be appreciated that the quantitative time periods for gait cycles and stance phases will extend over a certain range of values known to those of skill in the art, and that such time values depend on several variables, such as the physical characteristics of the wearer, the associated activity, and foot conditions present. 
     The selected physical properties set forth in  FIGS.  20 - 23    for layers  327 ,  329 ,  331 , and stratum  333  and inserts  337 , include durometer values as just one of many physical properties which have been combined to produce the ambulatory protective device  221  and its insole  321  described herein. 
     In certain implementations, the durometer value associated with the polymeric foam material of stratum  333  and the durometer value associated with the viscoelastic material of inserts  337  are selected to vary from each other within a range of 63% to 90%. In one suitable implementation, durometer of the polymeric foam material of stratum  333  ranges between  24  and  30  whereas the durometer of the viscoelastic material of stratum  333  ranges from  32  to  38 , both values measured using the Shore C scale under the SATRA TM  205  methodology. 
     Layers  327 ,  329 , and  331 , and stratum  333  and inserts  337  likewise have been configured so that viscoelastic inserts, in one possible implementation, have a viscosity ranging from  350  centipoise to  450  centipoise, whereas the polymeric foam material of stratum  333  is non-viscous. 
     Referring again to  FIGS.  11 - 15   , insole  321  of ambulatory protective device  221  comprises a cover layer  339  secured to top surface  341  of top layer  327 . Cover layer  339  is generally thin, meaning having a height which is relatively less than layers  327 ,  329 , and  331 , preferable being in the range of 0.5 millimeters to 2 millimeters, and comprised of woven material suitable for more directly engaging the lower plantar surface of the wearer’s foot, whether directly, such as through a sock, sleeve, or webbing, or indirectly through a bandage or other indirect contact. Accordingly, cover layer  339  may be configured to be friction reducing, water resistant, and antimicrobial. As such, insole  321  and its layers  339 ,  327 ,  329 , and  331  may be configured to extend over substantially all of footbed  239  and thus insole  321  may be thought of as comprising four, substantially planar strata. 
     Bottom layer  331  may be formed from a variety of suitable polymeric materials. In this implementation, bottom layer comprises a polyether, that is, a polyurethane material having physical properties set out in the ranges shown in the table of  FIG.  22   . In certain implementations, bottom layer  331  may comprise or consist essentially of the polymeric foam material marketed under the trademark PORON XRD. In one suitable implementation, the compression set and rebound values of bottom layer  331  are greater than or equal to the corresponding compression set and rebound values associated with the polymeric foam stratum  333  of middle layer  329 . For example, compression set value of bottom layer  331  may be between 40% and 60%, a rebound value may be between 37% and 47%, as set out in  FIG.  22   , whereas the compression set value of the ethylene vinyl acetate of stratum  333  may range from 20% to 40%, and the rebound value between 41% and 51%. 
     In further implementations, measuring with the Shore C hardness scale associated with medium hard materials, the polymeric material of top layer  327  may comprise the aforesaid polymeric foam, but may likewise comprise medium hard rubber, elastomers, or thermoplastic, among other polymeric materials, and is formed to have a durometer of 25 C to 30 C ± 3 C, and with an average or constant thickness of 7 mm. Stratum  333  may be formed similarly, and have similar thickness, except for trays or chambers  335 . Other durometers, and physical properties other than those employed in the described implementation herein, or as set out in the tables of  FIGS.  20 - 22   , are likewise within the scope of this disclosure. For example, inserts  337  may have durometer values ranging between 10 C to 55 C on the Shore C scale. 
     Layers  327 ,  329 ,  331 , and top cover layer  339 , as well as stratum  333 , may have constant thickness or varying thicknesses, depending on the application. Layer  327  has a lower surface with locations thermally bonded or affixed to portions of opposing surface of layer  329  underlying layer  327 , such as with an adhesive. 
     In certain implementations, middle layer  329  is a foam, open or closed cell, and of medium density, such as between 0.16 to 0.20 g/cm 3  (approximately 11 lbs/ft 3 ), and a medium durometer, such as between 22 C and 33 C. 
     Inserts  337  may be constructed of viscoelastic material, such as gel, but may likewise comprise or consist essentially of materials including, but not limited to, urethane polymers, silicone polymers, rubber polymers, and cyanoacrylate polymers. Inserts  337 , as illustrated, have respective, hemispherical shapes  340  ( FIG.  17   ), extending to terminate in arcuate or ovoid edges  338  from linear edges  342 , the arcuate edges  338  being located at proximal and distal locations of footbed  239  and linear edges  342  being interior to such arcuate edges  338 . Other shapes and configurations of inserts  337  may likewise be suitable. While inserts  337  are located in heel and forefoot areas  323 ,  325 , other variations of the illustrated implementation may employ only one of the inserts  337 , located in a corresponding one of the forefoot and heel areas  323 ,  325 , and such one-insert embodiments are likewise within the scope of this disclosure. 
     Trays or chambers  335  are bounded by circumferential walls  343  which define sides  345  of trays or chambers  335 . Chambers  335  are further bounded by overlying and underlying planar polymeric foam portions  349 ,  347 , respectively, to define respective tops  351  and bottoms  353  of chambers  335 . As such, sides  345 , tops  351 , and bottoms  353  define corresponding tray volumes bounded by such structures. Viscoelastic inserts  337  likewise extend to outer edges  355  and upper insert surfaces  357  and lower insert surfaces  359 . 
     In the illustrated implementation, linear edges  342  of inserts  337  coextend with opposing linear portions  348  of walls  343  of the chambers or trays  335 . The linear portions  348  are spaced proximally and distally from one another to define a central portion  361  on stratum  333 . As such, linear edges  342  represent the furthest inward or proximal location of viscoelastic material of inserts  337  and form respective boundaries  350  between the viscoelastic material of inserts  337  and the non-viscous, polymeric foam material of the central portion  361  of stratum  333 . The differing physical characteristics present on either side of boundaries  350  between central portion  361  and the viscoelastic inserts  337  contribute to the contact-pressure reduction characteristics described herein in relation to forefoot and heel areas  323  and  325 . The combination of differing materials with differing physical characteristics on either side of boundaries  350  produce a synergistic effect such that force reduction or contact pressure reduction during ambulation occurs in areas  323 ,  325  more readily with the combination of differing materials than would otherwise be achieved by one of the materials on its own. 
     In the illustrated implementations, inserts  337  and trays or chambers  335  are sized so that, whether insole  321  is unloaded or under maximum load during impact, toe-off, or other gait phases, outer edges  355  of inserts  337  do not contact opposing portions of the circumferential walls  343  of the chambers  335  in which inserts  337  have been received. As such, in both unloaded and loaded states, insole  321  has its outer edges  355  spaced from respective ones of circumferential walls  343  to define respective circumferential gaps  363  therebetween. Circumferential gaps  363  may be configured to have dimensions sufficient to maintain respective separations between the outer edges  355  of inserts  337  and respective sides  343  or walls of trays  335 . Such edges may extend about the entire circumference of the viscoelastic inserts  337 , but implementations where they do not extend about such entire circumference may likewise be suitable. As such, gaps  363  prevent contact between outer edges  355  of inserts  337  and walls  343  of trays  335 , even when under maximum load, and thus gaps  363  allow the physical properties associated with inserts  337  (as well as stratum  333 ) to remain unaffected by contact between opposing portions of outer edges  355  of inserts  337  and circumferential walls or sides of trays  343  when under load during ambulation. Otherwise stated, viscoelastic inserts  337  may “flatten out” or expand in response to orthogonal force from the wearer’s foot during ambulation, which, in turn, would increase the circumference defined by outer edges  355 . Without gaps  363  suitably configured as disclosed herein, viscoelastic inserts  337  would impinge against polymeric material of stratum  333  at the outer edges  355  of inserts  337 . Such impingement would alter compression set, rebound, and other physical characteristics of the viscoelastic material of inserts  337  during such impingement. Depending on how greatly the physical characteristics are altered by such impingement, the contact-pressure reduction properties associated with forefoot area  323  and heel area  325  may be adversely affected. 
     Upper and lower insert surfaces  357 ,  359  are spaced from each other to oppose tops and bottoms  351 ,  353  of trays  335  and may form an interference fit in both unloaded and loaded states, between inserts  337  and tops and bottoms  351 ,  353  of trays  335 . In the illustrated embodiment, the trays  335  comprise apertures extending between upper and lower surfaces of middle layer  329 . In such case, the overlying and underlying planar polymeric foam portions  347 ,  349  which bound trays  335  correspond to portions of top and bottom layers  327 ,  331 , respectively. Alternately, middle layer  329  may have one of its upper or lower surfaces extending across the area defined by trays  335  and thereby such portion of middle layer  329  would bound either the top or bottom of trays  335  and constitute either the underlying or overlying polymeric portions  347 ,  349 . In certain implementations, upper and lower insert surfaces  357 ,  359  are not adhered to tops and bottoms  351 ,  353  of trays  335 . 
     Although particular dimensions may vary depending on application and shoe size, in one suitable implementation, the full range of female and male foot sizes, layers  327 ,  329 , and  331 , in their uncompressed states, have a height ranging between 6 mm and 8 mm each, with cover layer  339  ranging between 0.5 and 1.5 mm. As such, the combined heights of layers  327 ,  329 , and  331  range from 18 mm to 24 mm. Gaps  363  between inserts  337  and walls  343  may range between 4 and 6 mm, and may be 5 mm. Linear edges  342 , which comprise the innermost point of viscoelastic material, may be located so as to be anterior or inward of heel areas  325  and forefoot area  323 , and quantitatively such linear edges  342  would be located between 100 mm and 102 mm from the outer edges of insole  321 . 
     Insole  321  may be received on an outsole  365  of ambulatory protective device  221 . Such outsole  365  has a bottom surface  366  configured to contact the ground when device  221  is worn and an upper surface  367 . Upper surface  367  may be configured to define a concavity  369  to receive insole  321  therein. 
     The use of the ambulatory protective devices disclosed herein, and the functioning of insole  321  therein, is readily appreciated by the above description. The type, thickness, compression set, rebound, durometer, viscosity, and other physical characteristics of the materials used in insole  321  may be varied depending on the application, or depending on the characteristics of ambulatory protective device  321  in which insole  321  is placed. As such, insole  321  may be formed in sizes corresponding to typical sizes of shoes, and may likewise be affixed in any suitable ambulatory protective device, such as a shoe, boot, brace, walker, or cast. Insole  321  may be in the form of an insert which can be removable. 
     Other implementations may or may not use all of the layers described herein, and thicknesses of the layers may vary, and the shapes, perimeters, and other dimensions may likewise be varied depending on the nature of insole  321  and its associated ambulatory protective boot. 
     Having described the various features and structures of the implementations of this disclosure, the scope of this disclosure is not confined to the details set forth and the patent is intended to include modifications and changes which may come within and extend from the following claims.