Abstract:
A prosthetic suspension-mounting system which employs an improved flathead bolt and socket centering cup combination for securement of an-amputee-limb enveloping liner within a prosthesis. The liner has a strap fixedly attached on the bottom end of the liner by a flathead bolt. The mounting system also includes a containment socket for seating the liner in the prosthesis using the head of the flathead bolt as a bearing surface against a floor of the socket. The containment socket has a slot there through at a position corresponding to the strap of the liner. The socket is provided with a disk-shaped recess having a flat floor, and the liner is provided with a distal flathead bolt having a flat head to provide a direct bearing surface against the floor of the socket. This provides a delimited bearing surface to keep the liner substantially centered within the prosthesis while still affording a lateral degree of freedom to avoid concentration of lateral forces.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application is a division of U.S. patent application Ser. No. 14/809,907 filed 27 Jul. 2015, which in turn derives priority from U.S. Provisional Patent Application No. 62/030,831 filed Jul. 30,2014, and is a continuation-in-part of U.S. Ser. No. 14/373,059 filed effective Dec. 14, 2012, both of which are incorporated herein by reference in their entireties. 
     
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
       [0002]    The present invention relates to prosthetics and, more particularly, to a prosthetic suspension mounting assembly comprising an improved socket centering block or cup and liner bearing pin which combine to provide a more robust mounting solution for above-the-knee and below-the-knee amputation patients seeking a suspension-mount for their prosthetic limb. 
       2. Description of the Background 
       [0003]    There are a variety of different types of prosthetic devices for patients that have had either transfemoral (above-knee) or transtibial (below the knee) amputation. Typically, post-operative prosthetic devices for either type of amputation begins with a liner that is rolled onto the residual limb. The liner is a soft, stretchy material that acts as an interface with the prosthesis. 
         [0004]    Once the liner is on, the residual limb then slides into a hard socket. This socket is specially made to fit and can be made out of a variety of materials. The hard socket for a transfemoral prosthesis has a knee joint connected to it, and the more fluid and natural the movement of the knee the better. Transtibial prosthetics have no knee joint. In both cases (with of without a knee joint) there is typically an aluminum carbon fiber tube to which a foot module is connected. 
         [0005]    For example, U.S. Pat. No. 5,653,786 to Naser issued Aug. 5,1997 shows a prosthetic device 20 having a generally cylindrical socket 24 with an opening for receiving an amputated limb. The socket 24 is closed at the other end, and is mounted on a bendable knee joint. Once the limb is properly received within the socket 24, straps 38 are adjusted so that a secure fit is achieved. The patient then is able to walk using the prosthetic device 20. 
         [0006]    With all such transfemoral and/or transtibial prosthetics (above &amp; below the knee), it is very important that the socket be securely fitted to the limb and secured in place. Stability is a common problem as many existing anchoring systems use a single attachment point to hold the residual limb in place, and this typically leads to extraneous pivoting, rotation and shift during ambulation. 
         [0007]    The prior art includes mechanical fixtures that lock the limb/liner in the socket. These typically include a socket molded into the distal end of the liner, and a pin threaded into the socket. The pin passes through the bottom of the socket and ratchet-locks into a base there below. U.S. Pat. No. 8,349,021 to Laghi et al. issued Jan. 8, 2013 gives an example. 
         [0008]    The prior art ICEX® Socket System is a total surface bearing (TSB) socket that pulls the limb into the socket using a lanyard. The lanyard is connected to the liner through a slot in the bottom of the socket. The lanyard is pulled to allow the patient&#39;s residual limb, which is enclosed in the silicone liner, to be drawn into the socket by the lanyard. The lanyard is then anchored to the front of the socket. 
         [0009]    There are also a number of “suction” type sockets that eliminate the lanyard. U.S. Pat. No. 6,645,253 to Caspars issued Nov. 11, 2003 shows a suction system that employs a vacuum pump to impart suction to the liner, the vacuum pump doubling as a shock absorber for the artificial limb. Commercially, this is known as the Harmony® System which pulls air from the sealed socket and evacuates moisture (sweat) buildup. A nonporous polyurethane liner (not shown) is fitted over the residual limb and is inserted in the socket. A vacuum pump is attached via a connector block beneath the socket to create a vacuum force which is coupled by a tube to the liner, thereby evacuating air and seating it to the residual limb. This provides a total-contact hypobaric suction equal weight distribution socket liner which tacks op to the skin of the residual limb and provides total contact with the limb. 
         [0010]    There is also a “suspension” type socket that suspends the limb within the socket. U.S. Pat. No. 6,793,682 to the present inventor discloses a “Sure-fit Prosthetic Attachment System” (known commercially as the KISS® System) for transfemoral and/or transtibial prostheses, comprising a Liner for enveloping an amputee limb. The liner has a strap attached at one end to a reinforcement plate that is sewn, bonded, and/or attached with Velcro to the liner toward the top, and a buckle is attached to the other end of the strap and is suspended thereby from the liner. Another strap is fixedly attached to the bottom end of the liner. The anchoring system also includes a containment socket for seating the liner. The containment socket has a pair of slots there through at positions corresponding to the buckle and strap of the liner, respectively. To apply the anchoring system, the patient first applies the liner to his/her limb. The liner is then inserted into the socket with the fastening strap and buckle protruding oat through the respective slots. The fastening strap is then threaded up through the buckle (running upward along the side of the socket) and is inserted there through. The patient pulls down on the strap, which works by pulley action to draw the liner down into the socket until the liner is securely seated in the socket. When fully seated, the fastening strap is secured to itself by hook-and-loop. The foregoing forms a suspension which holds the prosthesis on. Moreover, the fastening straps through slots absolutely prevent lateral shift as well as rotation. On the other hand, the patient need only readjust the Hook-and-loop closure to adjust the position of the limb within the socket Thus, if the limb changes position because of volume change and the distal migration of the limb into the socket, the prosthesis can easily be adjusted to compensate. Note that the fastening strap is attached to the distal end of the liner by a button-head cap screw  43  that is seated within a recess  35  in the base. The button-head of cap screw  43  centers the liner but affords no lateral freedom at all, and effectively concentrates all lateral forces at the distal end of the liner. In addition, the base is required to have a compound recess  35  which is semi-circular (on one side) with a pronounced indentation  37  in the center tor seating the head of screw  43  on the liner  10 . This compels a fairly thick base and large-profile mount. 
         [0011]    One of the primary concerns of prosthesis design and construction is that the device be lightweight and provide a comfortable fit to the residual limb, and it is extremely important to emulate a natural gait when in use. 
         [0012]    It would be more advantageous to provide a prosthetic mounting assembly that is lower in profile and which avoids concentrating lateral forces at a single point. 
       SUMMARY OF THE INVENTION 
       [0013]    It is, therefore, an object of the present invention to provide a prosthetic suspension-mounting system that employs an improved flathead holt and socket centering block, also referred to as a centering cap or socket centering cup, combination for securement of the liner within the socket of the prosthesis. 
         [0014]    In accordance with the above-described object, the present invention is a mounting system for a suspension-type transfemoral and/or transtibial prosthesis, including a liner for enveloping an amputee limb. The liner has a strap fixedly attached on the bottom end of the liner by a flathead bolt, and the head of the flathead bolt serves as a bearing surface. The mounting system also includes a containment socket for receiving and seating the liner and limb, and generally conforming thereto. In accordance with the invention, the socket is provided with a disk-shaped recess having a flat floor, and a puck- or disk-shaped centering cup is seated within the disk-shaped recess of the containment socket. The centering cup presents an upwardly-exposed, disk-shaped recess in which the flathead bolt sits, providing the opposing bearing surface. Both the centering cup and the socket have aligned slots there through at a position corresponding to the strap of the liner, to allow passage of the strap. 
         [0015]    The flat head of the distal flathead bolt has a diameter smaller than that of the centering cup recess, preferably between one-half and one-fifth the diameter of recess, and most preferably about one-third the diameter. This provides a circularly-constrained bearing surface for the flat head of the distal pin, keeping it substantially centered and yet affording a lateral degree of freedom to avoid concentration of lateral forces at the distal end of the liner. In addition, the flat-head bolt submerged in the disk-shaped recess allows a lighter lower-profile mount. 
         [0016]    To apply the anchoring system, the patient first applies the liner to his/her limb. The liner is then inserted into the socket with the fastening strap and buckle protruding out through the respective slots. The fastening strap is then threaded up through the buckle (mining upward along the side of the socket) and is inserted there through. The patient pulls down on the strap and it works by pulley action to draw the liner down into the socket until the liner is securely seated in the socket. When fully seated, the fastening strap is secured to itself by hook and loop. 
         [0017]    The foregoing forms a suspension which holds the prosthesis on. Moreover, the fastening straps through slots absolutely deter lateral shift as well as rotation. On the other hand, the patient treed only readjust the hook and loop closure to adjust the position of the limb within the socket. Thus, if the limb changes position because of volume change and the distal migration of the limb into the socket, the prosthesis can easily be adjusted to compensate. 
         [0018]    The above and other objects, features and advantages of the present invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which: 
           [0020]      FIG. 1  is a perspective exploded illustration of the sure-fit prosthetic anchoring system  2  according to the present invention. 
           [0021]      FIG. 2  is a close-up perspective view of the flat head bolt. 
           [0022]      FIG. 3  is a close-up top view of the centering cup. 
           [0023]      FIG. 4  is a close-up side cross-section of the centering cup. 
           [0024]      FIG. 5  is a close-up top cross-section of the centering cup. 
           [0025]      FIG. 6  is a close-up side view of the centering cup with optional crescent grooves designed to lock it into a thermoplastic/laminated socket without screws. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]      FIG. 1  is a perspective illustration of a sure-fit prosthetic anchoring system  2 . The anchoring system  2  is adapted for a patient that has undergone a limb reduction surgery resulting in an above-the-knee amputation. In a preferred embodiment, the anchoring system  2  generally includes a commercially-available liner  10  equipped with upper and lower strap-anchors  4 ,  6 , respectively. The upper strap anchor  4  is pivotally attached at one end by grommet-post  24  to a reinforcement plate  23 , plate  23  being a plastic member that is sewn, bonded and/or attached with hook and loop peripherally onto the liner  10  at an upper outside position as shown. In a preferred embodiment the grommet-post  24  comprises two screw-together sections having 1′ flanges which sandwich the plate  23  and upper strap  4  together. The other end of upper strap  4  bears a buckle  14  with a short length of extension strap past the buckle  14  to provide a finger-grip. The extension strap past the buckle  14  may be a short length of strap or plastic attached to the buckle itself, a slightly longer length sewn to the upper strap  4 , or art even longer length of strap/plastic attached by the grommet-post directly to the reinforcement plate  23 , in all cases serving to provide the user with a finger grip to pull the liner  10  down. 
         [0027]    In addition, a lower strap  6  is attached at one end to the bottom of the liner  10  by a flathead machine bolt  43  as described below. 
         [0028]    The liner  10  fits within a socket  12  and rests upon a centering cup  33 . In a preferred embodiment, the socket  12  is formed with, at least one slot  16  passing through an upper side (at the outside of the limb) for allowing the upper strap  4  and buckle  14  to pass outwardly therefrom. The socket  12  is also formed with one lower slot  17  at the bottom and aligned with the upper socket  16  for allowing the lower strap  6  to pass outwardly therefrom. 
         [0029]    The lower fastening strap  6  has a section  21  of hook-and-loop material at the distal end, and a mating section  22  of hook-and-loop material running lengthwise along its mid-section. Alternately, a single section of hook-and-loop material may run along the entire length of lower fastening strap  6 . The hook and loop is preferably a hybrid weave with hook and loop being mixed together, so there is no distinction between the hook and loop sides. Such hook and loop features are commercially available from Velcro® USA. In use, the patient would first apply liner  10  to limb. The liner  10  is then inserted into the socket with lower fastening strap  6  threaded through centering cup  33  out through lower slot  17 , and upper strap  4  with buckle  14  passing out through upper slot  16 . The junction of the upper strap  4  with the liner  10  limits downward insertion of the liner  10  into the socket  12  and seats the liner  10  onto the centering cup  33  as explained below. Importantly, this constraint avoids hunching of the liner fabric whilst seating the liner  10 , a very common problem with conventional liners/sockets. The lower fastening strap  6  is then threaded up through the protruding buckle  14  and downwardly, and the strap  6  is pulled tight until the liner  10  is securely seated in the socket  12  atop centering cup  33 . The fastening strap  6  is secured onto itself by joining the two sections  21 ,  22  of hook-and-loop material (or the one continuous section) in a loop. The foregoing forms a suspension which holds the prosthesis on and absolutely prevents lateral movement, pivotal shifting, and rotation. On the other hand, the simple hook-and-loop-attached strap  6  allows for convenient adjustment of the position of the limb within the socket  12 . Thus, if the limb changes position because of volume change and the distal migration of the limb into the socket, the prosthesis can easily be adjusted by adjusting straps  4 ,  6  to compensate. 
         [0030]    In an alternate embodiment, upper strap  4  with buckle  14  is not attached to liner  10 , but is attached directly to the exterior surface of socket  12  above slot  17  for fastening strap  6 . Slot  16  may thus be eliminated in this embodiment. As in previous embodiments, strap  4  may be pivotally attached at an upper outside position of socket  12  above slot  17  by a grommet-post to a reinforcement plate, which may be a plastic member that is sewn, bonded and/or attached with hook-and-loop to socket  12 . However, upper strap  4  may also be attached directly to socket  12  using any available means known in the art and capable of providing a secure connection. In the present embodiment, to use the device, the patient would first apply liner  10  to limb. The liner  10  is then inserted into the socket with lower fastening strap  6  threaded through centering cup  33  out through lower slot  17 . The lower fastening strap  6  is then threaded up through buckle  14 , which is attached via strap  4  to an exterior surface of socket  12  above slot  17 , and downwardly, and the strap  6  is pulled tight until the liner  10  is securely seated in the socket  12  atop centering cup  33 . The fastening strap  6  is secured onto itself by joining the sections  21 ,  22  of hook-and-loop material. As with the foregoing embodiment, the instant connection system forms a suspension which holds the prosthesis on and absolutely prevents lateral movement, pivotal shifting, and rotation, while the simple hook-and-loop-attached strap  6  allows for convenient adjustment of the position of the limb within the socket  12 . Thus, if the limb changes position because of volume change and the distal migration of the limb into the socket, the prosthesis can easily be adjusted by adjusting strap  6  within buckle  14  to compensate. 
         [0031]    Liner  10  is largely a standard transfemoral or transtibial suspension liner designed for amputees with amputations along the length of the tibia or femur. There are a variety of commercially-available suspension liners which will suffice, provided that they afford good suspension independent of volume fluctuations and provide a comfortable anatomical fit. These liners are typically formed of silicone or a gel blend with or without a fabric shell, and they may be equipped with a threaded socket assembly  42  at the bottom end for screw-insertion of flathead machine bolt  43  (or more conventional locking pin as known in the art). As disclosed in applicant&#39;s prior U.S. Pat. No. 6,793,682, the disclosure of which is hereby incorporated by reference in its entirety, the otherwise conventional liner is preferably modified by tethering buckle  14 , via upper strap  4 , on the outwardly facing side of the liner  10 . Strap  4  is secured to the liner  10  by first sewing, gluing and/or attaching with Velcro the reinforcement plate  23  peripherally to the shell of the lifter  10 , and then passing a grommet-post  24  through the tip of the upper strap  4  and through the plate  23 , thereby pivotally -anchoring strap  4  thereto. In other embodiments, as described above, the strap  4  may be attached directly to an exterior surface of socket  12 . 
         [0032]    Strap  4  may be a short length (approximately 6″) of braided Nylon or Dacron strap that is looped around one side of a rectangular buckle  14 , thereby suspending buckle  14  approximately 3-5″ downward from grommet-post  24  on liner  10  or socket  12 . The buckle  14  is a simple rectangular stirrup-type stainless fixture. It should be understood that alternate embodiments are possible without departing from the scope and spirit of the invention, the point being that the tethered buckle  14  must be suspended by a short distance. In a preferred embodiment, a short length (approximately 1-2″) of strap material is attached to the opposing side of buckle  14  in a like manner and extends therefrom to provide a finger-grip to facilitate insertion of the strap  4  and buckle  14  through the upper slot  16  in socket  12 . 
         [0033]    In addition to the upper strap  4  with buckle  14 , in a preferred embodiment the liner  10  is equipped with a lower fastening strap  6  comprising approximately a 2′ length of Nylon or Dacron braided strap attached at one end to, the bottom of liner  10 . As stated previously, liner  10  may be equipped with a threaded socket assembly  42  at the bottom end which includes a threaded metal screw-socket embedded in a concave robber cup which is then epoxied and/or sewn, or otherwise fixedly attached to the lower distal end of the liner  10 . 
         [0034]    As seen in  FIG. 2 , the lower strap  6  is doubled over at one end and a flathead machined hex drive bolt  43  is passed through the strap  6  and is screwed into the threaded socket assembly  42  to anchor the strap  6  to the liner  10 . The flathead hex drive bolt  43  may, for example, be a M10×12 12.9 thread flat bead stainless bolt having an oversized flat head with diameter at least twice that of the shaft, the head preferably having rounded edges as shown. In accordance-with the invention, bolt  43  not only attaches strap  6  to liner  10 , but also serves as a bearing surface against centering cup  33  as will be described. The lower fastening strap  6  has a section  21  of hook-and-loop material attached to the distal end, and a mating section  22  of hook-and-loop material running lengthwise along its mid-section for attaching strap  6  onto itself around buckle  14  (see  FIG. 1 ). 
         [0035]    Socket  12  is generally a conventional socket formed of flexible plastic that is vacuum formed. The socket  12  made in a custom-fitted component that is made in a conventional manner of a copolymer plastic, plastic polypropylene, polyester, acrylic/epoxy resin. The socket  12  may be vacuum formed or thermoformed by heating the plastic material and forming it over a mold. In a preferred embodiment, socket  12  is formed with an upper pass-through slot  16  along the outside. Alternatively, a series of parallel pass-through slots  16  may be provided to facilitate adjustment. The upper slot(s)  16  is positioned with respect to the liner  10  inserted therein so that it/they align with the upper strap  4 . Specifically, when the liner  10  is fully inserted, the pass-through slot  16  should be even level with the grommet-post  24  on liner  10 . Other pass-through slots  16 B, C . . . may be positioned slightly above or below for adjustment. This allows the tethered buckle  14  to be inserted directly through a slot  16  from inside the socket  12  to outside, such that downward tension on strap  4  anchors the grommet-post  24  directly against the slot  16 . In other embodiments, strap  4  with buckle  14  may be attached to the exterior surface of socket  12  via reinforcement plate  23  and grommet  24  as described herein. 
         [0036]    In addition to the upper slot(s)  16 , a lower pass-through slot  17  is positioned downwardly along the same side of the socket  12  in a preferred embodiment. The pass-through slot  17  is spaced in line with a centering cup slot  38  (described below) with respect to the bottom of the socket  12 . This way, when the liner  10  is fully inserted, the pass-through slot  17  allows the lower fastening strap  6  to be inserted there through. 
         [0037]    The outer end of the socket  12  is adapted to be connected to a conventional, bendable knee joint (a variety of which are presently available) as seen in  FIG. 1 . 
         [0038]      FIGS. 3-5  are a top view, side internal diagram, and top internal diagram, respectively, of the centering cup  33  insert as in  FIG. 1  which is attached internally to the bottom center of the socket  12 . The centering cup  33  is a puck-like member preferably formed of Delrin®, aluminum, or other sturdy lightweight composite material. In accordance with the invention, centering cup  33  is formed with a concave upper rim  34  leading into a central circular recess  35 . The concave upper rim  34  helps to seat and center the liner  10 . The recess  35  is substantially circular and defined by a perfectly flat floor  36 . The diameter of recess  35 /floor  36  is preferably within a range of from 2-4 times that of the oversized flat head hex drive bolt  43 , and most preferably approximately three times the diameter. The floor  36  effectively forms a “delimited” bearing surface for the flat head of bolt  43 , e.g., constraining the bolt  43  to within a circular degree of freedom limited by the walls of recess  35 . 
         [0039]    The recess  35  is interrupted on one side by a slot  38  through which the lower fastening strap  6  is passed. Slot  38  continues out through the side of centering cup  33  and aligns with the lower slot  17  of socket  12  to pass the lower strap  6  outward. A roller pin  39  straddles the slot  38 , and is journaled into the sidewalls of recess  35  suspended slightly above the floor  36  to guide and ease insertion of the strap  6  into slot  38  when the wearer dons the prosthesis. To apply the anchoring system  2 , the patient first applies the liner  10  to his/her residual limb. The liner  10  is then partially inserted into the socket  32  until lower fastening strap  6  can be threaded through the slot  38  in centering cup  33  and on outward through the lower slot  17  through socket  12 . In addition, the upper fastening strap  4  and buckle  14  may be passed outward through slot  16 , in embodiments where fastening strap  4  and buckle  14  are attached directly to liner  10 . The lower fastening strap  6  is then threaded up through the buckle  14  (strap  6  running upward along the side of the socket  12 ) and is inserted there through. The patient pulls down on the distal end of lower strap  6  which works by pulley action to draw the liner  10  down into the socket  12  until the liner  10  is securely seated in the socket  12 . When fully seated the lower fastening strap  6  is secured to itself by joining the sections  21 ,  22  of hook-and-loop material. The lower fastening strap  6  through lower slot  17  forms a first anchoring point, and in a preferred embodiment, upper strap  4  through upper slot  16  forms a second anchoring point, the combination of the two anchoring points serving to reduce lateral movement pivotal and proximal shift, and rotation. When such motion does occur, the delimited bearing surface of floor  36  partially supports the liner  10  on the flat head of bolt  43  yet gives it a lateral degree of sliding freedom (limited by the walls of recess  35 ) which avoids concentration of lateral forces at the distal end of the liner  10 . This effectively results in a “modified” suspension mount, the liner  10  being partially suspended by upper and lower straps  4 ,  6 , centered and partially supported by the concave tipper rim  34  of centering cup  33 , yet still being able to articulate therein in a ball-and-socket manner, and partially supported on the flat head of bolt  43  as it hears against floor  36 , yet still being able to shift therein within a limited degree of freedom. 
         [0040]    Importantly, the flat bearing surface of the low profile flat head belt  43  and flat floor  36  of the centering cup  33  combine to create the lowest profile attachment available for a residual-to-prosthetic socket using a gel liner with distal attachment. A primary goal when fabricating a transfemoral prosthesis is to be able to match the height of the anatomical knee center to the prosthetic knee center for a symmetrical gait as well as for cosmetic appearance. This is important during ambulation and when the individual is sitting. The present lower profile design is essential when fabricating a transfemoral prosthesis for an individual with a very long residual limb to obtain the stated results. 
         [0041]    The resulting modified suspension mount is more fluid and helps to closely mimic the natural movement of the knee, resulting in a more comfortable and natural prosthetic. When desired, the patient need only readjust the hook-and-loop closures to adjust the position of the limb within the socket  12 . Thus, if the limb changes position because of volume change and the distal migration of the limb into the socket, the prosthesis can easily be adjusted to compensate. Once the limb is properly received within the socket  12  and the straps  6  or  4  and  6  are appropriately adjusted so that a secure fit is achieved. 
         [0042]    In addition, the fiat-head bolt  43  seated in the shallow disk-shaped recess  35  allows a lighter lower-profile mount. 
         [0043]    Importantly, the modified suspension mount with strap  6  passing directly sideward out through slot  38  across flat floor  36  beneath roller pin  39  also avoids catching and/or entanglement of the strap  6 . 
         [0044]    If desired, a plurality of through-bores may be formed axially through the upper rim  34  for screw-attachment through the socket  12  into the base of the bendable knee joint (transfemoral) or the base of the shaft (transtibial), either of which are typically attached directly beneath the socket  12 . Alternatively, the through-bores may be eliminated and the centering cup  33  formed instead with a downwardly threaded hub for screw-attachment to the underlying base beneath socket  12 . 
         [0045]    As an alternative to through-bores/screws,  FIG. 6  is a close-up side view of a centering cup  33  with optional crescent grooves  39  designed to fixate the centering cup  33  inside a thermoplastic/laminated socket  12  without need of screws. In this case the peripheral walls of centering cup  33  are indented at a plurality (preferably four) evenly-spaced radial locations with fingernail-shaped “crescent” notches  39  tapered downward and opening upward toward concave upper rim  34 . The thermoplastic/laminated socket  12  may be formed with conforming outward protrusions keyed thereto, which effectively orient and index the socket  12  and liner  10 . This eliminates the need for without need for screw-fixation. The prosthetic anchoring system  2  described herein increases the stability of the liner anchor using the combined top-side and lower attachments to reduce extraneous up and down motion, pivotal and proximal shift, and rotation. When such motion does occur the specific configuration of the centering cup  33  and flathead bolt  43  comfortably accommodates it. 
         [0046]    Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.