Patent Publication Number: US-2022226131-A1

Title: Systems, devices and methods for multi-axial assemblies

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Application No. 63/139,248, filed Jan. 19, 2021, entitled “SYSTEMS, DEVICES AND METHODS FOR MULTI-AXIAL ASSEMBLIES”, and is a continuation in part of U.S. application Ser. No. 17/350,621, filed Jun. 17, 2021, entitled “MOUNTING BRACKET FOR CONNECTING A PROSTHETIC LIMB TO A FROSTHETIC FOOT”, and incorporates the disclosure of all such applications by reference. 
    
    
     BACKGROUND 
     This disclosure relates generally to prosthetics for lower limb amputees, and more specifically to methods and apparatus for multi-axial assemblies to provide rotation and vertical movement to lower limb prostheses. 
     BRIEF SUMMARY 
     Multi-axial prosthesis assemblies that include a resilient closed undulating member are used to provide vertical and rotational movement for lower limb prostheses. A shaft is located through a resilient bumper, with a first prosthetic member fixedly attached to the shaft and engages a first surface of the undulating member, and a second prosthetic member comprises a lumen to movably receive the shaft. The prosthetic members are engaged to the resilient bumper with projections that are located in the recesses of the resilient bumper and the prosthetic members and the bumper are configured so that the projections from each member are offset from the projections of the other member, which results in an undulating appearance to the outer surface of the resilient bumper. 
     In one embodiment, a prosthetic assembly is provided, comprising a resilient undulating body comprising an outer perimeter, a first surface, a second surface opposite the first surface, and an interior opening therebetween, a longitudinal shaft located in the interior opening of the undulating member, a first prosthesis body coupled to the longitudinal shaft and contacting the first surface of the undulating member, and a second prosthesis body comprising a longitudinal lumen and contacting the second surface of the undulating member, wherein the longitudinal shaft is movably located in the longitudinal lumen. The undulating body may comprise a first plurality of recesses on the first surface of the undulating body. The first prosthesis body may comprise a first plurality of projections configured to form a mechanical interfit with the first plurality of recesses of the undulating body. The undulating body may comprise a second plurality of recesses on the second surface of the undulating body. The second prosthesis body may comprise a second plurality of projections configured to form a mechanical interfit with the second plurality of recesses of the undulating body. The first plurality of recesses may be rotationally offset from the second plurality of recesses when no net rotational forces are acting on the undulating body. The first plurality of recesses may comprise an equal angular spacing relative to a central axis of the undulating body, and the second plurality of recesses may comprise an equal angular spacing relative to the central axis of the undulating body. The undulating body may further comprise an internal seal extending from the second surface of the undulating body that is radially offset from the outer perimeter of the undulating member and surrounding the interior opening of the undulating body. The angular spacing of the first plurality of recesses and the angular spacing of the second plurality of recesses may be 90 degrees. The first and second pluralities of recesses may be offset by 40 to 65 degrees. The first and/or second plurality of recesses may each comprise four recesses. Each recess of the first plurality of recesses and the second plurality of recesses may comprise an outer perimeter opening region, a radially inward wall opposite the outer perimeter opening, and opposing first and second side walls flanking the radially inward wall. The radially inward wall and the opposing first and second walls may comprise a U-shape on a transverse cross section through the undulating member. The recesses of the first plurality of recesses may further comprise a first surface opening region on the first surface of the undulating body, wherein the first surface opening region is contiguous with the outer perimeter opening region of the same recess, and a middle wall opposite the first surface opening region, wherein the middle wall is flanked by the first and second walls of the same recess. Each of the recesses of the second plurality of recesses may further comprise a second surface opening region on the second surface of the undulating body, wherein the second surface opening region is contiguous with the outer perimeter opening region of the same recess, and a middle wall opposite the second surface opening region, wherein the middle wall is flanked by the first and second walls of the same recess. Each recess of the first and second pluralities of recesses comprises a non-planar surface opening. The first prosthesis body may be integrally formed with the longitudinal shaft. The second prosthesis body may be configured to permit axial and rotational movement of the longitudinal shaft in the longitudinal lumen of the second prosthesis body. The prosthetic assembly may further comprise a shaft retainer removably attached to the shaft, and may be configured to resist separation of the longitudinal shaft and the second prosthesis body. The shaft retainer may comprise a removable fastener configured to removably attach to the longitudinal shaft, an annular seal configured to slidably seal the shaft retainer to the second prosthesis body, and a retaining washer with a circumferential recess in which the annular seal partially resides. The shaft retainer may further comprise a spring. The spring may be configured to maintain compression of the resilient body when the prosthetic assembly is in an unloaded state. The prosthetic assembly may further comprise an attachment pyramid. The attachment pyramid may be integrally formed with the longitudinal shaft. The second prosthesis body may further comprise a mounting interface configured to attach to a foot prosthesis. The mounting interface may comprise a plurality of lumens, each lumen configured to removably receive a fastener. The plurality of lumens may be a plurality of transverse lumens. The second prosthesis body may further comprise an annular cavity to at least partially receive the undulating body. The diameter of the interior opening of the undulating body may be greater than a diameter of the longitudinal shaft located in the interior opening of the undulating body. The longitudinal shaft may comprise a transverse stop surface located between a first end and a second end of the longitudinal shaft, and configured to displaceably abut against a corresponding stop surface of the second prosthesis body. The prosthetic assembly may further comprise a compression collar located between the first and second prosthesis bodies and configured to limit displacement of the longitudinal shaft relative to the longitudinal lumen of the second prosthesis body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, appending claims, and accompanying drawings where: 
         FIG. 1A  is a rear elevational view of a shock rotator assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 1B  is a side elevational view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 1C  is a front elevational view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 1D  is a top and view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 1E  is a bottom view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 1F  is a front perspective view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 1G  is a rear perspective view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 1H  is a side cross-sectional view of the assembly in  FIG. 1B  in accordance with exemplary embodiments of the present technology; 
         FIG. 2A  is a top view of the resilient body of the assembly in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 2B  is a side view of the resilient body of the assembly in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 2C  is a bottom view of the resilient body of the assembly in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 2D  is a top perspective view of the resilient body in accordance with exemplary embodiments of the present technology; 
         FIG. 2E  is a cross-sectional view of the resilient body in accordance with exemplary embodiments of the present technology; 
         FIG. 3A  is a front perspective view the exemplary assembly in  FIGS. 1A to 1G  attached to an exemplary foot prosthesis in accordance with exemplary embodiments of the present technology; 
         FIG. 3B  is a side elevational view the exemplary assembly in  FIGS. 1A to 1G  attached to an exemplary foot prosthesis in accordance with exemplary embodiments of the present technology; 
         FIG. 3C  is a top view of the assembly and prosthesis combination in  FIG. 3A  in accordance with exemplary embodiments of the present technology; 
         FIG. 3D  is a rear view of the assembly and prosthesis combination in  FIG. 3A  in accordance with exemplary embodiments of the present technology; 
         FIG. 3E  is a front view of the assembly and prosthesis combination in  FIG. 3A  in accordance with exemplary embodiments of the present technology; 
         FIG. 4A  is a rear view of the exemplary assembly in  FIGS. 1A to 1G , without the resilient body in accordance with exemplary embodiments of the present technology; 
         FIG. 4B  is a side view of the exemplary assembly in  FIGS. 1A to 1G , without the resilient body in accordance with exemplary embodiments of the present technology; 
         FIG. 4C  is a front view of the exemplary assembly in  FIGS. 1A to 1G , without the resilient body in accordance with exemplary embodiments of the present technology; 
         FIG. 4D  is a cross-sectional view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 4E  is a rear perspective view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 4F  is a front perspective view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 5A  is a top plan view of the first housing in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 5B  is a side plan view of the first housing in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 5C  is a bottom plan view, respectively, of the first housing in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 5D  is a cross-sectional view of the first housing  FIG. 5B  in accordance with exemplary embodiments of the present technology; 
         FIG. 5E  is a top perspective view of the first housing in accordance with exemplary embodiments of the present technology; 
         FIG. 5F  is a bottom perspective view of the first housing in accordance with exemplary embodiments of the present technology; 
         FIG. 6A  is a side elevational view of the shaft in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 6B  is a cross-sectional view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 6C  is a top perspective view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 6D  is a top plan view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 6E  is a bottom plan view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 7A  is a rear elevational view of the second housing in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 7B  is a side elevational view of the second housing in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 7C  front elevational view of the second housing in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 7D  is a cross-sectional view of the second housing  FIG. 7B  in accordance with exemplary embodiments of the present technology; 
         FIG. 7E  is a top perspective view of the second housing in accordance with exemplary embodiments of the present technology; 
         FIG. 7F  is a bottom perspective view the second housing in accordance with exemplary embodiments of the present technology; 
         FIG. 7G  is a top plan view of the second housing in accordance with exemplary embodiments of the present technology; 
         FIG. 7H  is a bottom plan view of the second housing in accordance with exemplary embodiments of the present technology; 
         FIG. 8A  is a top plan view of the retention washer in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 8B  is a side elevational view of the retention washer in  FIGS. 1A to 1G  in accordance with exemplary embodiments of the present technology; 
         FIG. 8C  is a cross-sectional view of the retention washer in  FIG. 7B  accordance with exemplary embodiments of the present technology; 
         FIG. 8D  is a bottom plan view of the retention washer in accordance with exemplary embodiments of the present technology; 
         FIG. 8E  is a bottom perspective view of the retention washer in accordance with exemplary embodiments of the present technology; 
         FIG. 8F  is a top perspective view of the retention washer in accordance with exemplary embodiments of the present technology; 
         FIG. 9  is a cross-sectional view of another embodiment of an assembly comprising an integrated first housing and shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 10  is a cross-sectional view of another embodiment of an assembly comprising a separate first housing and shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 11A  is a front elevational view of another embodiment of an exemplary shock rotator assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 11B  is a side cross-sectional view of the assembly in  FIG. 11A  in accordance with exemplary embodiments of the present technology; 
         FIG. 12A  is a rear view of another embodiment of the assembly, shown in  FIGS. 11A and 11B , without the resilient body; in accordance with exemplary embodiments of the present technology 
         FIG. 12B  is a cross-sectional view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 12C  is a rear perspective view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 12D  is a front perspective view of the assembly in accordance with exemplary embodiments of the present technology; 
         FIG. 13A  is a side elevational view of another embodiment of a shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 13B  is a cross-sectional view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 13C  is a top perspective view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 13D  is a top plan view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 13E  is a bottom plan view of the shaft in accordance with exemplary embodiments of the present technology; 
         FIG. 14A  is a rear perspective view of another embodiment of the second housing in accordance with exemplary embodiments of the present technology; 
         FIG. 14B  is a top view of the second housing in accordance with exemplary embodiments of the present technology; 
         FIG. 15  is a perspective view of the second housing shown in  FIGS. 14A-B  showing the annular flange in accordance with exemplary embodiments of the present technology; 
         FIG. 16  is a perspective view of the first housing, shown in  FIGS. 5A-D  and the shaft shown in  FIGS. 13A-13E  in accordance with exemplary embodiments of the present technology; 
         FIG. 17  is a side perspective view of the second housing with a portion of the shaft placed within the lumen and the shaft in the neutral position in accordance with exemplary embodiments of the present technology; 
         FIG. 18  is a side perspective view of the second housing with a portion of the shaft placed within the lumen and the shaft rotated clockwise from in the neutral position in accordance with exemplary embodiments of the present technology; and 
         FIG. 19  is a side perspective view of the second housing with a portion of the shaft placed within the lumen and the shaft rotated counterclockwise from in the neutral position in accordance with exemplary embodiments of the present technology. 
     
    
    
     Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that may be performed concurrently or in a different order are illustrated in the figures to help to improve understanding of embodiments of the present technology. 
     DETAILED DESCRIPTION 
     The present technology may be described in terms of functional block components and various processing steps. Such functional blocks may be realized by any number of components configured to perform the specified functions and achieve the various results. For example, the present technology may be used with a prosthetic foot for various amputation types (above knee, below knee, etc.). In addition, the present technology may be practiced in conjunction with any number of materials and methods of manufacture and the system described is merely one exemplary application for the technology. 
     While exemplary embodiments are described herein in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical structural, material, and mechanical changes may be made without departing from the spirit and scope of the invention. Thus, the following descriptions are not intended as a limitation on the use or applicability of the invention, but instead, are provided merely to enable a full and complete description of exemplary embodiments. 
     The function and features of a lower limb prosthetic may be selected based on the user&#39;s ability to ambulate and to transfer from various positions from a chair or bed. For patients that are able to ambulate at a single speed on level surface, a solid ankle-cushion heel foot prosthesis, or a single-axis prosthesis may be selected, for users who are able to traverse curbs, stair and uneven surfaces, a flexible-keel foot or a multi-axial ankle/foot prosthesis may provide improved ambulation efficiency and safety. For users with greater rehabilitation potential and are able to ambulate at different speeds and traverse most environmental obstacles, a multi-axial ankle foot with vertical-loading pylon may be beneficial. 
     In some examples, a prosthetic assembly may be provided that permits limited axial rotation and vertical loading between two housings in which a resilient body is located. The resilient body provides limited resilient vertical loading and axial rotation as it undergoes deformation by the relative displacement and motion between the two housings. A movable shaft is attached to one of the housings, and is longitudinally and rotationally movable relative to a lumen located in the other housing in which the shaft resides. A retention member or retention assembly may be provided at the end of the shaft to releasably and movably retain the shaft in the other housing. The shaft is typically a rigid shaft that does not flex under typical loads, but in other embodiments, the shaft may comprise a resiliently flexible shaft with one or more bend regions, e.g., helical spring region that can bend away from its central longitudinal axis. 
     To resist substantial separation of the resilient body from the housings, the resilient body may comprise a closed shape with an interior opening in which a portion of the shaft is located. To provide increasing resistance to greater degrees of axial rotation, the housings and the resilient body may comprise complementary projections and recesses configured to resist greater amounts of rotational slippage. The complementary interface may be sized and located to also distribute rotational forces acting on the resilient body in order to reduce the concentration of forces that may increase the fracture or breakage of the resilient body. In some further embodiments, the configuration of the assembly may include projections from the first and second housings into recesses located in the resilient body. The recesses may be located around the periphery of the resilient body such that each recess is open and confluent on both a side surface and a horizontal surface of the resilient body. The angular arrangement of the recesses may be configured such that recesses are located on alternating horizontal surfaces to receive alternating projections from the two housings. This results in an undulating configuration to the side or periphery surface of the resilient body. The resilient body may further comprise one or more flanges or sealing structures to help resist water or liquid intrusion into the interior regions of assembly. 
     The first and second housings of the assembly may also comprise recesses or cavities to partially contain a portion of the resilient body, and an interface to fixedly or movably couple to the shaft of the assembly. In some variations, a first or upper end of the shaft is configured to fixedly attach to the first or upper housing, so that the first housing and shaft move in a fixed relationship relative to the resilient body and second housing. In other variations, the first housing and shaft may be integrally formed. Typically, the shaft is inserted through the resilient body and into a longitudinal lumen of the second or lower housing in which the shaft movably resides. 
     The first or upper housing, or the first or upper end of the shaft, may comprise an attachment interface to attach to a pylon or residual limb socket. The second or lower housing may comprise an attachment interface to attach the assembly to a foot prosthesis. 
     The second or lower end of the shaft may be accessible at the second or lower end of the second housing, and a retention member or assembly may be attached to the shaft in order to retain the shaft in the lumen of the second housing. The retention member or assembly may be detached in order to perform maintenance on the assembly or to change out the resilient body. 
     In one exemplary embodiment as described generally above, a prosthetic assembly  100  that provides vertical shock absorption and rotational movement is depicted in  FIGS. 1A to 1H . The assembly  100  comprises a resilient bumper or body  102 , located between a first or upper housing  104  and a second or lower housing  106 . A longitudinal or vertical shaft  108  is coupled to the first housing  104 , passing through the resilient body  102  and coupled to the second housing  106 . A retention member or retention assembly  110  is attached to the shaft  108  to resist separation of the shaft from the second housing  106 . The assembly  100  is configured to permit limited longitudinal and rotational displacement of the shaft  108  relative to the second housing  106 , with the resilient body  102  providing increasing resilient resistance to increasing vertical compression and increasing rotational displacement. A pyramid attachment structure  112  is provided on the shaft  108  for attachment of the assembly  100  to a pylon or residual limb socket (not shown), while the second housing  106  is configured for attachment to a foot prosthesis. A cover piece  114  may also be provided on the assembly  100 . In some variations, the cover piece  114  may provide a cosmetic/trademark function and/or a protective function to protect one or more areas of the assembly  100  from intrusion of unwanted materials (e.g., dirt, liquid) and/or inadvertent snagging of the assembly  100  with environmental objects and hazards. Although the assembly  100  described in this particular embodiment may be provided separate from a foot prosthesis, in other examples, the assembly  100  may be integrated with foot prosthesis at the point-of-manufacture. 
     The shaft  108  is sized to pass through a lumen  122  of the lower housing  106  such that a retention member or retention assembly  110  may be used to releasably retain the shaft  108  in the lumen  122 . 
     The resilient body  102  of the assembly  100  may comprise a resilient material such as silicone, rubber, polyurethane, urethane, thermoplastic elastomers, thermoplastic vulcanizates (e.g., SANTOPRENE™ and ELASTRON™), and the like. In some further embodiments, the resilient material may comprise a durometer in the range of 40 A to 100 A, or 50 A to 90 A or 60 A to 90 A, and may be selected based on the user&#39;s weight and/or activity level. In some examples, the resilient body  102  is selected to provide up to 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm or more vertical deflection or compression, and selected to provide up to 5 degrees, 6 degrees, 7 degrees, 8 degrees, 10 degrees, 12 degrees, 14 degrees, 16 degrees, or 20 degrees of rotational deflection, or more. 
     In one exemplary analysis, resilient bodies of various durometers were evaluated using various loads to achieve a minimum of 2 mm of vertical deflection and a minimum of 12 degrees of angular deflection. The results of the analysis are depicted below as Table 1: 
     
       
         
           
               
               
               
            
               
                   
                   
               
               
                   
                 Vertical Loads 
                 Torsion Loads 
               
            
           
           
               
               
               
               
               
               
            
               
                 Resilient 
                 Static 
                 Vertical 
                   
                   
                 Actual 
               
               
                 Body 
                 Test 
                 Deflection 
                 Down 
                 Rotation 
                 Angle (°) 
               
               
                 Durometer 
                 Load 
                 Actual 
                 Force 
                 Force 
                 each 
               
               
                 (shore A) 
                 (lbs) 
                 (inches) 
                 (lbs) 
                 (in-lbs) 
                 direction 
               
               
                   
               
               
                 64A 
                 186 
                 &gt;.08 
                 121 
                 118 
                 &gt;12 
               
               
                 70A 
                 277 
                 &gt;.08 
                 180 
                 181 
                 &gt;12 
               
               
                 77A 
                 360 
                 &gt;.08 
                 234 
                 228 
                 &gt;12 
               
               
                 83A 
                 462 
                 &gt;.08 
                 300 
                 220 
                 &gt;12 
               
               
                   
               
            
           
         
       
     
     In some examples, the density of the material of the resilient body may be different or lower inside the resilient body versus the exposed surfaces of the resilient body, or the exposed surfaces may comprise a different material. The resilient body may also comprise a coating, e.g. a hydrophobic or water-resistant coating to reduce water absorption into the resilient body. 
     As shown in  FIGS. 1A to 1H , the upper housing  104  comprises a plurality of inferior projections  116  extending from its peripheral surface  118  and lower surface  120 . The inferior projections  116  are located in and form a complementary interfit with the upper recesses  218  of the resilient body  102 . Likewise, the lower housing  106  comprise a plurality of superior projections  126  extending from its peripheral surface  130  and upper surface  132 , and are located in and form a complementary interfit with the lower recesses  220  of the resilient body  102 . The lower housing  106  further comprises an attachment interface  124  which is used to attach the assembly to a foot prosthesis (not shown). 
     Referring to  FIGS. 2A to 2E , the resilient body  102  may comprise a first or upper surface  200 , a second or lower surface  202 , a central lumen  204  therebetween defining an inner surface  206 , and an outer lateral surface  208 . Each of the upper and lower surfaces  200 ,  202  may comprise a generally planar configuration, but in other examples, may comprise a concave or convex configuration, or other non-planar configuration, such as a frustoconical configuration, or combination thereof. The central lumen  204  has a generally circular cross-sectional shape across its central longitudinal axis  210 , but in other variations may comprise a triangular, square, rectangle, or oval shape, for example. The diameter, transverse dimension or surface area of the central lumen  204  may be constant, or may vary along the longitudinal axis  210 . As depicted in exemplary resilient body  102  in  FIG. 2E , the central lumen  204  may comprise a larger diameter about its upper and lower regions  212 ,  214 , but a smaller diameter about the middle region  216 . In this example, the transitions along the regions  212 ,  214 ,  216  are gradual, such that the inner surface  206  comprise a convex configuration on the cross-sectional view in  FIG. 2E , but in other examples, the transitions may be abrupt, with a stepped surface configuration, for example. Similarly, the outer surface  208  of the resilient body  102  also comprises a convex shape on cross-section, but in other examples, may comprise a concave, linear, frustoconical or other shape. The larger diameter may be in the range of 0.4 inches to 3.0 inches, 0.6 inches to 2.0 inches or 0.8 inches to 1.3 inches. The smaller diameter may be in the range of 0.20 inches to 2.8 inches, 0.4 inches to 1.8 inches or 0.7 inches to 1.2 inches, and the average diameter may be in the range of 0.3 inches to 2.9 inches, 0.5 inches to 1.9 inches or 0.75 inches to 1.25 inches. The central lumen  204  may be sized such that its inner surface  206  is spaced apart and not in contact with the shaft  108  during typical usage. In some variations, some radially inward bulging of the inner surface  206  may be expected during vertical compression of the resilient body  102 , and thus the dimension of the central lumen  204  may be size sufficiently to reduce the likelihood that the inner surface  206  will contact the shaft  108  during compression. The annular gap between the inner surface  206  and the shaft  108  may be in the range of 0.001 inches to 1.0 inches, 0.02 inches to 0.5 inches or 0.03 inches to 0.25 inches. The average diameter or maximum transverse dimension of the resilient body  102  across opposite sides of the outer surface  208  may be in the range of 0.7 inches to 3.5 inches, 1 inches to 2.5 inches or 1.5 inches to 2.25 inches. 
     Referring still to  FIGS. 2A to 2E , the exemplary resilient body  102  comprise a set of upper recesses  218  and a set of lower recesses  220 . The recesses in each set of recesses may comprise the same recess shape or configuration, and may be equally spaced apart, though between the upper recesses  218  and the lower recesses  220 , the angular orientations are offset such that the angular position of each upper recess  218  is spaced equally apart from the adjacent lower recesses  220 , as is each lower recess  220  is spaced equally apart from the adjacent upper recesses  218 . In this example, each set of recesses  218 ,  220  comprises four recesses that are spaced 90 degrees apart around the resilient body, and are offset by 45 degrees between the two sets of recesses  218 ,  220 . This permits the resilient body  102  to be assembled or serviced without requiring a particular angular alignment or top/bottom orientation, which may simplify assembly and replacement, and may reduce premature wear. In other examples, however, the resilient body  102  may not have such symmetry and therefore may be limited to a single or smaller number of positions/orientations. In other variations, for example, one or more recesses may comprise a different size, shape or spacing than the other recesses of the same set, and/or the number of recesses between the two sets of recesses may be different. In other examples, the number of recesses in each set of recess may be in the range of 2 to 5 recesses, 3 to 4 recesses, or 3 to 5 recesses. 
     Referring still to the recesses  218 ,  220  depicted in  FIGS. 2A-2E , the recesses comprise openings  222 ,  224  that are angled or non-planar, with portions  222   a ,  224   a  of the openings  222 ,  224  on the upper and lower surfaces  200 ,  202  of the resilient body  102 , respectively, that are contiguous with portions  222   b ,  224   b  of the openings  222 ,  224  that are located on the outer surface  208 . Thus, each opening  222 ,  224  has a non-planar configuration with a boundary located on the outer surface  208  and either upper or lower surfaces, and where the different portions  222   a ,  222   b ,  224   a ,  224   b  are generally orthogonal to each other. In this particular embodiment, the recesses  218 ,  220  comprise an inner wall  226 ,  228  such that the recesses  218 ,  220  do not open to the central lumen  204  of the resilient body  102 . This configuration may reduce the intrusion of debris or foreign matter into the device during use, which may interfere with smooth movement of the shaft  108  with the lumen  204  of the lower housing  106 . This configuration may also shift, distribute or transfer torque exerted by the upper and lower housings  104 ,  106  from the inner regions to the outer regions of the resilient body  102 , which will reduce torque forces acting on the resilient body  102  and may prolong its usable life being requiring replacement. 
     Each of the recesses  218 ,  220  also comprise side walls  230 ,  232  and end walls  234 ,  236 . As shown in  FIGS. 2A-2E , the transitions between the walls  226 ,  228 ,  230 ,  232 ,  234 ,  236  and with the upper and lower surfaces  200 ,  202  of the resilient body  102  may be rounded rather than sharply angled. This may reduce the concentration of forces transferred from the lower and upper extensions of the upper and lower housings  104 ,  106 , or otherwise distribute the transferred forces or stresses throughout the resilient body  102 , which may reduce the risk of fracture or tearing, thereby extending the life of the resilient body  102 . The height  238  of each recess  218 ,  220  may be characterized by as the distance between either upper or lower surfaces  200 ,  202  of the resilient body  102  to the corresponding end wall  234 ,  236 , as best seen in  FIG. 2B . The height  238  may be in the range of 0.1 inches to 3 inches, 0.2 inches to 1.5 inches or 0.3 inches to 1 inches. The height  238  of each recess  218 ,  220  may also be characterized as a percentage of the height of the resilient body  102 , e.g., the distance between the upper and lower surfaces  200 ,  202 . In the particular embodiment depicted in  FIG. 2B , each of the recesses  218 ,  220  have a relative height  238  of 50% of the resilient body  102 , each with an end wall  234 ,  236  at the midplane  240  of the resilient body  102 . In other variations, the recesses may have a relative height  238  in the range of 20% to 80%, 30% to 70%, 40% to 60%, or 50% to 70%, for example. The width  242  of each recess  218 ,  220  may be the average width or the maximum width based on the distance between the sidewalls, and may be in the range of 0.04 inches to 1.5 inches, 0.125 inches to 1 inches or 0.15 inches to 0.5 inches. The radial depth  244  of the recesses  218 ,  220  may be characterized by the distance between the outer surface  208  and the inner walls  226 ,  228  of the recesses  218 ,  220 , as depicted in  FIG. 2C , and may be in the range of 0.04 inches to 1.5 inches, 0.1 inches to 1 inches or 0.2 inches to 0.5 inches. In some variations, the width of each recess  218 ,  220  between the side walls  230 ,  232  may be tapered in a radially inward direction, e.g., each side wall  230 ,  232  is located in a plane intersecting the center longitudinal axis  210  of the resilient body  102 . In other variations, the angles of the side walls  230 ,  232  relative to the plane may vary from about ±1 to ±5 degrees, ±2 to ±10 degrees, or ±4 to ±20 degrees, relative to the plane intersecting the center longitudinal axis  210 , for example. In some further variations, the angles of the side walls  230 ,  232  may be altered such that the side walls  230 ,  232  are parallel, or where the width of each recess  218 ,  220  is constant or increases toward the center axis, so that during rotation, the resilient member has a radial displacement force component that drives the resilient member towards the center line. This is in contrast to side wall angles that generate a radial outward displacement force from portions of the resilient body  102  being squeezed between, which may reduce the working life of the resilient member. The radial depth  244  of the recesses  218 ,  220  may also be characterized as a relative percentage of the radial or annular distance  246  between the inner and outer surfaces  206 ,  208  of the resilient body  102 , also depicted in  FIG. 2C . The relative radial depth  244  may be in the range of 30% to 90%, 40% to 80% or 50% to 80%, for example. The radial thickness  248  of the inner walls  226 ,  228  may also be characterized as the radial distance between the inner walls  226 ,  228  and the inner surface  206  of the central lumen  204 . The radial thickness  248  may be in the range of 0.04 inches to 2.0 inches, 0.07 inches to 1 inches or 0.1 inches to 0.5 inches, and may also be characterized as a relative thickness  248  as a percentage of the annular distance  246 . The relative thickness  248  may be in the range of 10% to 70%, 20% to 60%, or 20% to 50%, for example. These dimensions may be measured based on the average dimension and exclude the curved regions of the recesses  218 ,  220  at the transitions between different walls and surfaces. 
       FIGS. 5A to 5F  depicts additional details of the upper housing  104  of the assembly  100  depicted in  FIGS. 1A to 1H . As noted previously, the upper housing  104  comprises a plurality of inferior projections  116  extending from its peripheral surface  118  and lower surface  120 . When assembled, the inferior projections  116  are located in and form a complementary interfit with the upper recesses  218  of the resilient body  102 . In this exemplary embodiment, the peripheral surface  118  comprises a convex, tapered shape with a larger diameter or transverse dimension in the lower region  500  closer to the inferior projections  116  and lower surface  120 , and a reduced diameter or transverse dimension in the upper region  502  of the upper housing  104 . Because of the taper, the upper surface  128  has a minimal or substantially reduced surface area as compared to the lower surface  120 . In other variations of the upper housing  104 , however, the peripheral surface  118  may not be as tapered or may comprise a generally cylindrical in shape, or comprise a non-circular or polygonal shape with linear or vertically oriented surface. 
     The average length  506 , average width  508  and average radial depth  510  of each inferior projection  116  may be complementary to the sizes of the corresponding recesses  218 . In some variations, the dimensions  506 ,  508 ,  510  of each inferior projection  116  may be slightly smaller or larger than the dimensions  238 ,  242 ,  244  of the recesses  218 . In some examples, the inner surface  512  of each inferior projection  116  may have a generally vertical orientation or parallel orientation relative to the center longitudinal axis  210  of the upper housing  104 . The outer surface  514  of each inferior projection  116  may comprise a taper that is in continuity with the taper and/or curvature of the peripheral surface  118 , and may be flush, recessed, or protrude from the portion of the recess  218  on the outer surface  208  of the resilient body  102 . Like the recesses  218 , the inferior projections  116  may comprise rounded edges between the transitions of the lower surface  120 , inner surface  512 , outer surface  514 , and side walls  516  and end wall  518 . 
     The upper housing  104  further comprises a central lumen  504  between the lower and upper surfaces  120 ,  128 . The central lumen  504  is configured to receive the longitudinal shaft  108  of the assembly  100 . As illustrated in  FIG. 5D , the central lumen  504  comprises a reduced dimension upper region  504   a , and enlarged dimension lower region  504   b , with a stepped surface  504   c  therebetween. The upper region  504   a  may comprise a threaded interface for attaching the shaft  108  to the upper housing  104 , though in the variations the lower region  504   b  or both regions  504   a ,  504   b  may comprise threads, or other type of mount (e.g. bayonet mount) may be provided between the upper housing and shaft. A glue, such as an acrylate or cyanoacrylate may also be added to the threaded interface, to resist decoupling from torsional forces acting through the shaft. 
     As illustrated in  FIGS. 1A to 1H and 6A to 6C , the pyramid attachment structure  112  is provided on the shaft  108  for attachment of the assembly  100  to a pylon or residual limb socket. The pyramid  112  typically comprises an industry standard four-sided configuration, but in other examples, may comprise an alternative or proprietary design. The pyramid configuration may be changed by using a different shaft with a different pyramid configuration. Referring to  FIGS. 6A to 6C , the pyramid  112  is located at a first end  600  of the shaft  108  and may include a threaded lumen  602  to facilitate attachment of the pyramid  112 . Next to the pyramid  112  is an attachment region or interface  604  of the shaft  108  that forms a complementary interfit with the central lumen  504  of the upper housing  104 . This may be a threaded interface as depicted, or a bayonet mount or other type of mechanical interfit or friction fit as noted above. As depicted in  FIGS. 1A to 1H , the shaft  108  may be configured such that when assembled with the upper housing  104 , the pyramid  112  protrudes from the upper surface  128  of the upper housing  104 . Adjacent to the attachment interface  604  of the shaft  108  may be a tool interface  606 , which may be used to grip the shaft  108  with a wrench or pliers or other tool when coupling or decoupling the shaft  108  and the upper housing  104 . Although the tool interface  606  depicted in  FIGS. 6A to 6C  is a hexagonal interface, in other variations, the tool interface  606  may be square or rectangular or other polygonal shape, or may comprise a lumen in which a torque bar may be inserted to facilitate rotational coupling and decoupling of the shaft  108  and upper housing  104 . 
     In still other variations of the assembly  900 , the upper housing  902  and the shaft  904  and pyramid  906  may be integrally formed as a monolithic component, as shown in  FIG. 9 . In still other examples, as illustrated in  FIG. 10 , the assembly  1000  may comprise a pyramid structure  1002  that is integrally formed with the upper housing  1004  of the assembly  1000 , but with a recess or lumen  1006  in the upper housing  1004  to couple to a shaft  1008 . In this particular embodiment, the lumen  1006  of the upper housing  1004  is open at both ends and is located through the pyramid  1002  and the main body  1008  of the upper housing  1004 , but in other variations, the lumen  1006  may be close-ended and with only a lower opening  1010  of the lumen, with the upper opening  1012  in the pyramid  1002 . 
     Referring back to  FIGS. 6A to 6E , adjacent or inferior to the tool interface  606  of the shaft  108  is the body  608  of the shaft  108 , which is configured to reside and move in the lumen  122  of the lower housing  106  when assembled. The length of the body  608  of the shaft  108  may be in the range of 1.0 inches to 7.0 inches, 2.0 inches to 5.0 inches or 2.0 inches to 4.0 inches. The diameter or cross-sectional dimension of the shaft  108  may be in the range of 0.12 inches to 1.5 inches, 0.25 inches to 1.25 inches or 0.3 inches to 0.9 inches. Different lengths of the shaft  108  may also be provided in order to accommodate different patient preferences, height, and functional levels, with corresponding different heights of the resilient body  102 . 
     The second or lower end  610  of the shaft  108  is sized and configured to extend out from the lumen  122  of the lower housing  106 . A retention member or assembly  110  may be attached to the second end  610  to resist pullout of the shaft  108  from the lower housing  106 , but may be configured to permit some vertical displacement of the shaft  108  within the lumen  122 . This acts as a shock absorber as the upper housing  104  and lower housing  106  resiliently compress the resilient body  102 . In this particular example, the retention assembly  110  is attachable to the second end  610  of the shaft  108  by a closed threaded lumen  612 , but in other variations, may be attached via a clevis pin or other coupling interface. The retention assembly  110  is also configured to permit the shaft  108  to rotate within the lumen  122  and thereby to permit axial rotation. In the particular examples depicted in  FIGS. 1A to 1H , the axial rotation is limited by the increasing resistance to rotation provided by rotational compression of the resilient body  102  between the inferior and superior projections  116 ,  126 . In other variations, however, the retention member or assembly  110 , the shaft  108  and/or the lower housing  106  may be configured with one or more complementary flanges and recesses to provide a hard limit angle limit to the rotation range. 
     Referring now to the lower housing  106 , which is detailed in  FIGS. 7A to 7H , as noted previously, the lower housing  106  comprise a plurality of superior projections  126  extending from its peripheral surface  130  and upper surface  132 . The superior projections  126  are positioned and configured to form a complementary interfit with the lower recesses  220  of the resilient body  102 . The lower housing  106  further comprises a longitudinal lumen  122  to receive the shaft  108 . The lower housing  106  comprises a main body  700  in which the lumen  122  resides, and also includes the prosthesis attachment interface  124  described earlier. The lumen  122  may include a lubricant or lubricious coating to facilitate longitudinal and rotational movement of the shaft  108  therein, but in some examples, a tubular bearing may be provided to facilitate such movement, such as a SPRINGGLIDE™ bearing (St. Gobain; Courbevoie, France). 
     Like the inferior projections  116  of the upper housing  104 , the average length  704 , average width  706  and average radial depth  708  of each superior projection  126  may be complementary to the sizes of the corresponding recesses  220  of the resilient body  102 . In some variations, the dimensions  704 ,  706 ,  708  of each superior projection  126  may be slightly smaller or larger than the dimensions  704 ,  706 ,  708  of the recesses  220 . In some examples, as depicted in  FIG. 7C , the inner surface  714  of each superior projection  126  may have a generally vertical orientation or parallel orientation relative to the longitudinal axis of the upper housing  104 . The outer surface  716  of each superior projection  126  may comprise a taper that is in continuity with the taper and/or curvature of the peripheral surface  132 , and may be flush, recessed, or protrude from the portion of the recess  220  on the outer surface  208  of the resilient body  102 . Like the recesses  220 , the superior projections  126  may comprise rounded edges between the transitions of the superior surface  132  of the lower housing  106 , and the inner surface  714 , outer surface  716 , side walls  718  and end wall  720  of the superior projections  126 . 
     The superior surface  132  of the lower housing  106  may comprise a similar configuration as the lower surface  120  of the upper housing  104  but with an angular offset to the projections  126 . In the embodiment depicted in  FIGS. 7A to 7E , however, the superior surface  132  further comprises an annular projection or flange  710 . The annular flange  710  is spaced radially inward from the peripheral surface  130  and the superior projections  126 , surrounding the longitudinal lumen  122  of the lower housing  106 . This flange  710  may be configured to insert or reside inside the central lumen  204  of the resilient body  102 . In some variations, the annular flange  710  may reduce the risk of eccentric displacement of the resilient body  102  during various compression and rotational movements, and may also limit the radially inward bulging of the inner surface  206  during vertical compression, and/or may act as barrier reduce the intrusion of debris and liquid into the lumen  122  of the lower housing  106 . The flange  710  also provides additional support for longer tubular bearings that might be used in the lumen  122 . The use of a longer bearing may augment or reduce resistance that may be generated by off-axis forces or forces transverse to the longitudinal shaft and lumen. This may also improve bearing life and tactile prosthesis response. In embodiments comprising a tubular bearing, the ratio of the bearing length to the bearing inner diameter may in the range of 1.5:1 and 10:1, or 2:1 to 6:1 or 3:1 to 5:1. The flange  710  also allows the resilient member to be placed lower in the overall prosthesis, relative to the lumen  122 , which can shorten the build height of the prosthesis, which allows the use of the prosthesis across a greater range of residual limb lengths. Depending on the height of the annular flange  710 , the flange  710  may also provide a hard compression stop if the amount of vertical compression results in the annular flange  710  abutting against the inferior surface  120  of the upper housing  104 . In some variations, the height of the annular flange  710  is the range of 0.02 inches to 1.5 inches, 0.1 inches to 0.5 inches or 0.12 inches to 0.3 inches. The wall thickness of the flange  710  may be in the range of 0.04 inches to 0.5 inches, 0.07 inches to 0.3 inches or 0.1 inches to 0.2 inches. The inner diameter may be 0.25 inches to 1.5 inches, 0.3 inches to 1.0 inches or 0.5 inches to 0.75 inches, and the outer diameter may be 0.3 inches to 2.0 inches, 0.4 inches to 1.5 inches or 0.5 inches to 1.0 inches. 
     The peripheral surface  130  of the lower housing  106  may also comprise a convex, tapered shape with a larger diameter or transverse dimension in the upper anterior region  702 . The attachment interface  124  of the lower housing  106  may comprise a flat, vertically planar surface to facilitate attachment of the lower housing  106  to a foot prosthesis, but in other variations, the lower housing  106  may comprise an angled or horizontal region to facilitate attachment to foot prostheses with a corresponding angled or horizontal attachment site. 
     The attachment interface  124  of the lower housing  106  comprise one or more threaded lumens  712  to facilitate attachment of the lower housing  106  to a foot prosthesis using screws, bolts or other fasteners. In  FIGS. 3A to 3E , the assembly  100  is attached to a foot prosthesis  300  with a vertically mounted attachment interface, using bolts  302 ,  304 . 
     As depicted in  FIG. 7A , the attachment interface  124  of the lower housing  106  may also comprise cover attachment sites  722  which facilitate the attachment of cosmetic covers  114  to the body  700  of the lower housing  106 . The lumen  122  of the lower housing  106  may comprise a retention cavity  724  in which the retention assembly  110  resides. In other variations, however, a retention cavity is not provided such that the retention assembly  110  may protrude from the lumen  122  and the lower housing  106 . 
     As noted previously, the retention member or assembly  110  may be attached to the shaft  108  using the threaded lumen  612  at the lower end of the shaft  108 , as depicted in  FIG. 1H . The retention assembly  110  may comprise a bolt  800  or other type of fastener, and a retention washer  802  which is movable in the retention cavity  724 . The retention washer  802  resists further upward displacement of the shaft  108  once it abuts the superior surface of the retention cavity  724 . The retention washer  802  comprises a washer cavity  804  to receive the bolt  800 , and may include a reduced diameter shaft cavity  804   a  and an enlarged head cavity  804   b  which allows the bolt  800  to have a recessed position partially in the retention washer  802  when attached to the shaft  108 . To reduce the risk of debris and liquid interfering with the movement of the shaft  108  in the lumen  122  of the lower housing  106 , an O-ring or annular sliding seal  806  may be provided on the retention washer  802 . The seal  806  is maintained in a slidable arrangement with the retention cavity  724  by a seal recess  808  on the retention washer  802 , bound by recess walls  808   a  and  808   b , as shown in  FIGS. 8A to 8F . The retention washer  802  may also comprise a spring recess  810  that is superior or proximal to the recess wall  808   a . Referring back to  FIG. 1H , the spring recess  810  permits the positioning of a spring  812  which can be used to provide some limited inferior bias to the shaft  108  and may keep the resilient body  102  in a minimum amount of compression to the assembly  100 . This minimum compression may be useful if or as the resilient body  102  undergoes any permanent compression or compression set during use. The spring  812  may be a helical spring or a wave washer, for example. The seal  804  may comprise silicone, Buna-N rubber, and Fluorinated elastomer such as VITON™ (Chemours; Wilmington, Del.). 
       FIGS. 4A to 4F  illustrate the assembled configuration of the upper housing  104 , lower housing  106  and shaft  108 , without the resilient body  102 . The shaft  108  may be configured such that the tool interface  610  is located generally at the level of the longitudinal location of the resilient body  102 . The gap or distance between the lower surface  120  of the upper housing  104  and the superior surface  132  of the lower housing  106  may be equal to the unstrained height of the resilient body  102 . In other examples, the gap or distance may be smaller than the unstrained height of the resilient body  102 , such that when assembled, the upper and lower housings  104 ,  106  place the resilient body  102  in vertical compression at baseline. This baseline compressed configuration may make the haptic feel of the assembly to be more linear or predictable compared to a baseline configuration that is not compressed or where the housing gap is greater than the unstrained height of the resilient body  102 . 
     The upper housing  104 , lower housing  106 , shaft  108  and/or cover piece  114  may comprise stainless steel (e.g. 17-4 stainless steel), titanium or cobalt chromium, aluminum or other metal, and anodized variants thereof, but in other examples may comprise a rigid polymer, ceramic or a composite thereof. 
     In another exemplary embodiment, shown in  FIGS. 11A and 11B , a prosthetic assembly  1100  that provides vertical shock absorption and rotational movement is depicted in  FIGS. 11A and 11B . The assembly  1100  comprises many components similar to the prosthetic assembly  100  described above and the similar components will not be discussed in detail below. The assembly  1100  comprises a resilient bumper or body  102 , located between a first or upper housing  104  and a second or lower housing  1102 . A longitudinal or vertical shaft  1104  is coupled to the first housing  104 , passing through the resilient body  102  and coupled to the lower housing  1102 . A retention member or retention assembly  110  is attached to the shaft  1104  to resist separation of the shaft  1104  from the lower housing  1102 . The assembly  1100  is configured to permit limited longitudinal and rotational displacement of the shaft  1104  relative to the lower housing  1102 , with the resilient body  102  providing increasing resilient resistance to increasing vertical compression and increasing rotational displacement. 
     The shaft  1104  is sized to pass through a lumen  1106  of the lower housing  1102  such that a retention member or retention assembly  110  may be used to releasably retain the shaft  1104  in the lumen  1106 . 
     As illustrated in  FIGS. 11A to 11B and 13A to 13E , the pyramid attachment structure  1108  is provided on the shaft  1104  for attachment of the assembly  1100  to a pylon or residual limb socket. The pyramid  1108  typically comprises an industry standard four-sided configuration, but in other examples, may comprise an alternative or proprietary design. The pyramid configuration may be changed by using a different shaft with a different pyramid configuration. Referring to  FIGS. 13A to 13E , the pyramid  1108  is located at a first end  1110  of the shaft  1104  and may include a threaded lumen  1112  to facilitate attachment of the pyramid  1108 . Next to the pyramid  1108  is an attachment region or interface  1114  of the shaft  1104  that forms a complementary interfit with the central lumen  504  of the upper housing  104 . This may be a collar interface as depicted, or a thread interface, as discussed above, a bayonet mount or other type of mechanical interfit or friction fit as noted above. As depicted in  FIGS. 11A to 11B , the shaft  1104  may be configured such that when assembled with the upper housing  104 , the pyramid  1108  protrudes form the upper surface  128  of the upper housing  104 . Adjacent to the attachment interface  1114  of the shaft  1104  may be a bore interface  1116 , which may be used to grip the shaft  1104  with a wrench or pliers or other tool when coupling or decoupling the shaft  1104  and the upper housing  104 . 
     The bore interface  1116  may comprise at least one contact surface  1126  configured to contact the rounded lobes on the flange of the lower housing to restrict torsional rotation between the upper housing  104  and the lower housing  1102 , as will be further discussed below. Although the contact surfaces  1126  depicted in  FIGS. 13A to 13E  are a rectangular interface, in other variations, the contact surfaces  1126  of the bore interface  1116  may be square or hexagonal or other polygonal shape, or may comprise a lumen in which a torque bar may be inserted to facilitate rotational coupling and decoupling of the shaft  1104  and upper housing  104 . The contact surfaces  1126  of bore interface  1116  on the shaft  1104  be configured to provide a hard limit angle limit to the rotation range with respect to the lower housing  1102  as shown in  FIGS. 18 and 19 . The contact surfaces  1126  may be configured in any suitable shaft to cooperate with the internal configuration of the flange of the lower housing  1102 . 
     Referring back to  FIGS. 13A to 13E , adjacent or inferior to the bore interface  1116  of the shaft  1104  is the body  1118  of the shaft  1104 , which is configured to reside and move in the lumen  1106  of the lower housing  1102  when assembled. The length of the body  1118  of the shaft  1104  may be in the range of 1.0 inches to 7.0 inches, 2.0 inches to 5.0 inches or 2.0 inches to 4.0 inches. The diameter or cross-sectional dimension of the shaft  1104  may be in the range of 0.12 inches to 1.5 inches, 0.25 inches to 1.25 inches or 0.3 inches to 0.9 inches. In one embodiment, the diameter of the shaft may be approximately 0.55 inches and the length of the body of the shaft may be approximately 3.83 inches. Different lengths of the shaft  1104  may also be provided in order to accommodate different patient preferences, height, and functional levels, with corresponding different heights of the resilient body  102 . 
     The second or lower end  1120  of the shaft  1104  is sized and configured to extend out from the lumen  1106  of the lower housing  1102 . A retention member or assembly  110  may be attached to the second end  1120  to resist pullout of the shaft  1104  from the lower housing  1102 , but may be configured to permit some vertical displacement of the shaft  1104  within the lumen  1106 . This acts as a shock absorber as the upper housing  104  and lower housing  1102  resiliently compress the resilient body  102 . In this particular example, the retention assembly  110  is attachable to the second end  1120  of the shaft  1104  by a closed threaded lumen  1122 , but in other variations, may be attached via a clevis pin or other coupling interface. The retention assembly  110  is also configured to permit the shaft  1104  to rotate within the lumen  1106  and thereby to permit axial rotation. 
     In the particular examples depicted in  FIGS. 1A to 1H , the axial rotation is limited by the increasing resistance to rotation provided by rotational compression of the resilient body  102  between the inferior and superior projections  116 ,  126 . In other variations, however, the retention member or assembly  110 , the contact surfaces of bore interface on the shaft  108  and the rounded lobes on the flange of the lower housing  106  may be configured to provide a hard limit angle limit to the rotation range. 
     In the embodiment depicted in  FIGS. 14A, 14B, and 15 , the lower housing  1102  may comprise an annular projection or flange  1124 . The remainder of the components for the lower housing  1102  are similar to those described above regarding lower housing  106 . 
     The annular flange  1124  is spaced radially inward from the peripheral surface  130  and the projections  126 , surrounding the longitudinal lumen  1106  of the lower housing  1102 . This flange  1124  may be configured to insert or reside inside the central lumen  204  of the resilient body  102 . In some variations, the annular flange  1124  may reduce the risk of eccentric displacement of the resilient body  102  during various compression and rotational movements, and may also limit the radially inward bulging of the inner surface  206  during vertical compression, and/or may act as barrier reduce the intrusion of debris and liquid into the lumen  1106  of the lower housing  1102 . 
     The flange  1124  also provides additional support for longer tubular bearings that might be used in the lumen  1106 . The use of a longer bearing may augment or reduce resistance that may be generated by off-axis forces or forces transverse to the longitudinal shaft  1104  and lumen  1106 . This may also improve bearing life and tactile prosthesis response. In embodiments comprising a tubular bearing, the ratio of the bearing length to the bearing inner diameter may in the range of 1.5:1 and 10:1, or 2:1 to 6:1 or 3:1 to 5:1. The flange  1124  also allows the resilient member to be placed lower in the overall prosthesis, relative to the lumen  1106 , which can shorten the build height of the prosthesis, which allows the use of the prosthesis across a greater range of residual limb lengths. Depending on the height of the annular flange  1124 , the flange  1124  may also provide a hard compression stop if the amount of vertical compression results in the annular flange  1124  abutting against the inferior surface  120  of the upper housing  104 . In some variations, the height of the annular flange  1124  is the range of 0.02 inches to 1.5 inches, 0.1 inches to 0.5 inches or 0.12 inches to 0.3 inches. The wall thickness of the flange  1124  may be in the range of 0.04 inches to 0.5 inches, 0.07 inches to 0.3 inches or 0.1 inches to 0.2 inches. The inner diameter may be 0.25 inches to 1.5 inches, 0.3 inches to 1.0 inches or 0.5 inches to 0.75 inches, and the outer diameter may be 0.3 inches to 2.0 inches, 0.4 inches to 1.5 inches or 0.5 inches to 1.0 inches. In one embodiment, the height of the flange may be approximately 0.47 inches and the outside diameter may be approximately 0.92 inches. In one embodiment, the lobed design the flange  1124  wall thickness may be irregular within the range of 0.16 to 0.60 inches and the inside of the lobed feature has an inscribed circle diameter of approximately 0.599 inches at minimum to approximately 0.800 inches at maximum. 
       FIGS. 12A to 12D  illustrate the assembled configuration of the upper housing  104 , lower housing  1102  and shaft  1104 , without the resilient body  108 . The shaft  1104  may be configured such that the bore interface  1116  is located generally at the level of the longitudinal location of the resilient body  102 . The gap or distance between the lower surface  120  of the upper housing  104  and the superior surface of the lower housing  1102  may be equal to the unstrained height of the resilient body  102 . In other examples, the gap or distance may be smaller than the unstrained height of the resilient body  102 , such that when assembled, the upper and lower housings  104 ,  1102  place the resilient body  102  in vertical compression at baseline. This baseline compressed configuration may make the haptic feel of the assembly to be more linear or predictable compared to a baseline configuration that is not compressed or where the housing gap is greater than the unstrained height of the resilient body  102 . 
     Referring now to  FIGS. 14 and 15  the flange  1124  may comprise an internal bore  1128  having a plurality of rounded lobes  1130 . The rounded lobes  1130  and the contact surfaces  1126  of the bore interface  1116  on the shaft  1104  are configured to limit the rotation of the upper housing  104  with respect to the lower housing  1102 . The rounded lobes  1130  are spaced apart and located opposite of one another on the internal bore  1128 . In one embodiment the internal bore  1128  may comprise four rounded lobes, that are configured to contact the four contact surfaces  1126  of bore interface  1116  on the shaft  1104 . 
     In various embodiments, the contact surfaces  1126  of bore interface  1116  on the shaft  1104  and the rounded lobes  1130  on the flange  1124  of the lower housing  1104  may be configured to provide a hard limit angle limit to the rotation range as shown in  FIGS. 18 and 19 . In one embodiment, the angle limit of rotation is approximately 15° in the clockwise and counterclockwise directions for a total range of rotation of approximately 30°. In various embodiments, the number of contact surfaces  1126  of bore interface  1116  on the shaft  1104  are the same as the rounded lobes  1130  on the flange  1124 . 
       FIG. 17  shows the lower housing  1102  with a portion of the shaft  1104  placed within the lumen  1106  and the shaft  1104  in the neutral position. The contact surfaces  1126  of the bore interface  1116  are not in contact with the rounded lobes  1130  on the flange  1124  of the lower housing  1102 . 
       FIG. 18  is a side perspective view of the lower housing  1102  with a portion of the shaft  1104  placed within the lumen  1106  and the shaft  1104  rotated clockwise from the neutral position. The contact surfaces  1126  of the bore interface  1116  are in contact with the rounded lobes  1130  on the flange  1124  of the lower housing  1102  to resist torsional rotation of the upper housing  104  attached to the shaft  1104  with regard to the lower housing. 
       FIG. 19  is a side perspective view of the lower housing  1102  with a portion of the shaft  1104  placed within the lumen  1106  rotated counterclockwise from the neutral position. The contact surfaces  1126  of the bore interface  1116  are in contact with the rounded lobes  1130  on the flange  1124  of the lower housing  1102  to resist torsional rotation of the upper housing  104  attached to the shaft  1104  with regard to the lower housing. 
     The specific examples and descriptions herein are exemplary in nature and variations may be developed by those skilled in the art based on the material taught herein without departing from the scope of the present subject matter. 
     The technology has been described with reference to specific exemplary embodiments. Various modifications and changes, however, may be made without departing from the scope of the present technology. The description and figures are to be regarded in an illustrative manner, rather than a restrictive one and all such modifications are intended to be included within the scope of the present technology. Accordingly, the scope of the technology should be determined by the generic embodiments described and their legal equivalents rather than by merely the specific examples described above. For example, the steps recited in any method or process embodiment may be executed in any order, unless otherwise expressly specified, and are not limited to the explicit order presented in the specific examples. Additionally, the components and/or elements recited in any apparatus embodiment may be assembled or otherwise operationally configured in a variety of permutations to produce substantially the same result as the present technology and are accordingly not limited to the specific configuration recited in the specific examples. 
     Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to problems or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components. 
     As used herein, the terms “comprises,” “comprising,” or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present technology, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same. 
     Furthermore, in understanding the scope of the present invention, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including,” “having” and their derivatives. Any terms of degree such as “substantially,” “about” and “approximate” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies. 
     The present technology has been described above with reference to a preferred embodiment. However, changes and modifications may be made to the preferred embodiment without departing from the scope of the present technology. These and other changes or modifications are intended to be included within the scope of the present technology, as expressed in the following claims.