FIELD

The present invention relates to a prosthesis; in particular, a prosthesis for receiving a portion of a limb, i.e. an arm or a leg.

BACKGROUND

Various types of prostheses are known. For example:

US7611476 "Vacuum-sealed orthotic prosthetic, and other body worn devices" describes various prostheses including a flexible sleeve extendable over a user's joint, a strap for reducing the perimeter of the sleeve on a first side of the user's joint proximal the user's body, and an artificial body part (i.e. a tool) secured to the sleeve on a second side of the user's joint.

US514225 "Artificial leg" describes a flexible sleeve (for receiving a user's hip); a waist strap at a first axial end of the sleeve for securing the sleeve around a user's waist; an upper leg residual limb receiving socket (i.e. a mount) at a second axial end of the sleeve; and a lower leg (i.e. a tool) secured to the socket.

US3262131 "Artificial leg with detachable stump supporting sock" describes a prosthesis including: a rigid mount for receiving a user's lower leg stump / residual limb therein; a flexible sleeve that extends from the mount over the user's knee; an annular elastic border for reducing the perimeter of the flexible sleeve around the user's upper leg; leg bars extending from the rigid mount; and screws or rivets for securing the leg bars to the rigid mount

Known prosthetics tend to be heavy and bulky. Lighter prosthetics are available but are very expensive and not generally available to the public other than through insurance programmes. The greatest need for prosthetics is in countries that have experienced conflict over the past 100 years and in which unexploded ordnance is prevalent. Such countries include Sri Lanka, Cambodia and Afghanistan to name a few. Loss of a limb is traumatic regardless of circumstances but in undeveloped countries prosthetics are either not available or are of such poor quality that their use does not result in particular improvements to quality of life.

It is against the foregoing background that the present invention has arisen. SUMMARY

Various embodiments of the present disclosure will be explained below in detail with reference to the accompanying drawings. The following detailed description refers to the accompanying drawings that show, by way of illustration, specific aspects and embodiments in which the present invention may be practiced. Other embodiments may be utilized, and structure, logical and electrical changes may be made without departing from the scope of the present invention. The various embodiments disclosed herein are not necessary mutually exclusive, as some disclosed embodiments can be combined with one or more other disclosed embodiments to form new embodiments.

An aspect of the present invention provides a prosthesis comprising: a sleeve for receiving a portion of a limb therein, the sleeve defining a longitudinal axis extending between a proximal end of the sleeve and a distal end of the sleeve, wherein the sleeve is formed from a flexible fabric material at least at the proximal end thereof and the prostheses further comprises a rigid socket at the distal end of the sleeve for providing a stop against which a part of the limb abuts, wherein the socket is at least partially defined by a section of the sleeve.

Use of a flexible sleeve in a prosthesis has many advantages over the prior art. The closest prior art known to the applicant is US3262131. This document describes a stump sock for receiving a knee joint. The stump sock is formed from a fabric material which is gripped between a stump receiving member and a rigid sleeve. In contrast, the claimed invention comprises a fully fabric sleeve construction that is able to be formed from a single manufacturing operation. The claimed sleeve construction is thus lightweight and easily manoeuvrable. The claimed sleeve construction is also easy to manufacture using reliable and repeatable manufacturing techniques as will be described further below. The materials used to manufacture the claimed sleeve constructions are low cost and readily available. Prostheses according to aspects of the invention can be manufactured and supplied at a significantly lower cost than prostheses of the prior art.

In one embodiment the fabric material comprises at least an outer layer of a resiliently biased material and an inner layer of a soft material having a low coefficient of friction.

The fabric material may further comprise a cushioning layer between the inner and outer layers of material. The cushioning layer may be polyurethane foam. In one embodiment the prosthesis comprises a rigid insert between the inner layer and the outer layer of the sleeve and extending at least partially around the circumference of the sleeve at the distal end thereof.

In one embodiment, the outer layer of material and/or inner layer of material and/or rigid insert are heat activated.

FIGURES

Aspects and embodiments of the invention will now be described by way of reference to the following figures:

Figure 1 is an isometric view of a prosthesis according to a preferred embodiment of the invention.

Figure 2 is a cross-sectional view of a portion of the prosthesis of figure 1.

Figure 3 is a detailed view of a rigid mount configured for attachment to the prosthesis of figures 1 and 2.

Figure 4 illustrates a mating interface of a tool configured for engagement with the rigid mount of figure 4.

Figure 5 shows a flow chart according to the method of manufacture of a prosthesis according to an embodiment of the invention.

Figure 6 illustrates a second embodiment of the invention.

DESCRIPTION

Turning now to the figures, a system of the present disclosure will be discussed in more detail. A prosthesis 10 includes a sleeve 12 defining a longitudinal axis A-A between a proximal end 12a and a distal end 12b thereof. The proximal end 12a of the sleeve 12 is configured to receive a residual part of an amputee's limb. For the purposes of this description reference is made to a prosthesis 10 suitable for receiving a residual part of an amputee's arm, in particular an arm that has been amputated at the elbow. Flowever, it will be appreciated that aspects and embodiments of the invention will be equally suitable for use with other limbs and with arms having been amputated at other locations.

The sleeve 12 is sized and shaped to receive a user's residual limb extending below the elbow via the proximal end 12a of the sleeve 12 and extend beyond the user's elbow over a portion of the user's upper arm.

The sleeve 12, in a preferred embodiment, is formed from an outer layer of material 14 and an inner layer of material 16. The outer layer of material 14 may be polyester or a polyester blend. The inner layer of material 16 may be softer than the outer layer of material 14 and may have a high coefficient of friction to resist slipping. An example of the inner layer of material 16 comprises a blend of microfiber polyester and lycra or nylon. In some embodiments, the inner layer of material may further be provided with silicone strips (not shown) (preferably, platinum-cured silicone rubber strips) to further increase the coefficient of friction of the inside of the sleeve 12. In use, the inner layer of material and/or silicone strips help inhibit sliding of the sleeve 12 along a user's residual limb or proximal limb. The silicone strips may comprise an elongated piece of silicone material that is either flat or which incorporates raised features such as contours, lines, bumps, shapes, for example. The silicone strips may be orientated longitudinally or laterally in relation to the axis A-A of the prosthesis, or a combination of longitudinally and laterally. The, or each, silicone strip may be sewn to the inner layer of material or applied directly in fluid form and allowed to cure in-situ. The location of the, or each, silicone strip may be selected depending on a particular user's anatomy.

The sleeve 12 is secured to a user's residual limb by way of one or more constrictors 28. Two constrictors 28a and 28b are shown in figure 1. The first constrictor 28a is located at or near the proximal end 12a of the sleeve 12. The second constrictor 28b is located between the first constrictor 28a and the mount 22 (as described below). The first 28a and second 28b constrictors are positioned at different angular orientations around the longitudinal axis A-A of the sleeve 12. In each case, the constrictors 28, of which there may be just one or more than two, comprise an annular article that may be bonded to the sleeve 12 or attached thereto. The annular article secures a wire or string type member that extends from the constrictor 28 through the fabric of the sleeve 12. When the prosthesis 10 is positioned on a user's residual limb, the wire or string type member is pulled tight around the constrictor 28 to draw the fabric of the sleeve 12 tightly around the user's proximal limb. This, combined with the high coefficient of friction of the inner layer of material 16 of the sleeve and/or silicone strips attached thereto, provides an effective mechanical resistance against removal of the prosthesis 10 from the user's proximal limb during normal use.

The above example of a constrictor 28 is given by way of example only. It will be appreciated that other such constrictors may be utilised in conjunction with aspects and embodiments of the invention. For example, the, or each, constrictor 28 may be in the form of a strap with Velcro ^® . In use, the strap (not shown in the illustrated embodiments) would be looped around a user's proximal limb (i.e. between a user's elbow and shoulder), tightened around the proximal limb and secured in this tightened configuration by Velcro ^® . Other examples include using a woven string (i.e. a shoelace) with a drawstring lock or with beads along its length to catch and lock the string at predetermined increments; an inextensible wire with a spool (optionally, motorised) regulated by a pawl and ratchet mechanism; webbing (e.g. nylon, polypropylene or cotton) with a ladder lock to form a loop and vary the perimeter length; or an elastic undersized U-shaped member that can be splayed to locate over a user's proximal limb.

With either example of constrictor 28 the periphery of the sleeve 12 is reduced to tighten the sleeve 12 around the user's proximal limb. Basic principles of human anatomy dictate that the elbow joint of the majority of individuals has a greater perimeter than that of the user's humerus. The constrictor 28, when applied, thus inhibits the proximal end of the sleeve from passing the user's elbow.

In some embodiments, the length of the sleeve 12 may be adjusted in an axial direction. To facilitate this, a portion of the sleeve 12 material at the proximal end 12a thereof is configured to concertina when compressed and expand when extended. The sleeve 12 length can be fixed by way of one or more fasteners, i.e. a Velcro ^® strap or buckle.

A socket 18 is defined by the sleeve 12 at the distal end 12b thereof. The socket 18 is formed from a portion of the sleeve wall 12c that extends from the proximal end 12a to the distal end 12b thereof and terminates in a return flange 12d, as shown more clearly in figure 3. To provide rigidity, a support layer of material 20 is provided between the outer layer of material 14 and inner layer of material 16 at least in the region of the sleeve 12 at the distal end 12b thereof. The support layer of material 20 is heat activated to retain the desired form of the prosthesis 10. The sleeve 12 construction is shown more clearly in figure 2. As shown in figure 1, a rigid mount 22 is secured to the sleeve 12. The mount is shown in more detail in figure 3. The mount 22 is made of a single piece of rigid plastic material and can be formed using standard manufacturing techniques such as injection moulding and additive manufacturing, for example. The mount 22 is axially spaced along the sleeve 12 from the, or each, constrictor 28. The mount 22 is substantially right angled such that a first projection 22a is positioned under the return flange 12d of the sleeve 12 to provide support to a residual limb positioned within the sleeve. A second projection 22b extends substantially at right angles from the first projection 22a along the sleeve wall 12c in the direction of the proximal end 12a of the sleeve 12. The mount 22 is secured to the sleeve wall 12c by way of one or more fixings 24. In the illustrated embodiment, the one or more fixings 24 are screws that engage against the second projection 22b of the mount 22 and screw into the support layer of material 20 of the sleeve 12. It will be appreciated that attachment of the mount 22 to the sleeve wall 12c may be way of other fixing types, i.e. adhesive, magnetic, snap-fit, for example. As illustrated, the second projection 22b extends between 30 and 50% longitudinally along the sleeve wall 12c. It will be appreciated that the second projection 22b may extend less than 30% or more than 50% longitudinally along the sleeve wall 12c.

The mount 22 comprises a magnet 26 for attachment of one or more tools 28. As shown in figure 3, the magnet 26 is provided within the second projection 22b of the mount 22. However, in other embodiments the magnet 26 may be provided within the first projection 22a of the mount 22, positioned external to the first projection 22a or second projection 22b of the mount 22 or provided as part of or external to the portion of the sleeve wall 12c in the vicinity of the mount 22. The mount 22 is shown in more detail in figure 4. In a preferred embodiment, the second projection 22b of the mount 22 is provided with at least three magnets 26. The mount 22 is orientated in figure 4 to show the external faces thereof when applied to a prosthesis 10. The magnets 26 are inserted into small holes in the internal face of the second projection 22b of the mount 22. The wall thickness of the second projection 22b of the mount 22 is nominally 0.5mm to ensure that the magnetic properties of the magnets are not blocked by the material of the mount 22.

The first projection 22a of the mount 22 further comprises a keyway 22d for receiving a portion of the tool 28. The keyway 22d is defined by an opening into the first projection 22a of the mount 22 substantially perpendicularly to the longitudinal axis of the prosthesis 10. The keyway 22d allows the tool 26 to move in a single plane relative to the mount 22. The magnet(s) 26 thus secure the tool 28 in a locked position when inserted fully into the keyway 22d. The second projection 22b of the mount 22 further comprises a plurality of longitudinally orientated slots 22e therethrough. The keyway 22d may comprise one or more grooves or detents 22e therein for engagement with corresponding projections of the tool 28. The projections snap into the grooves or detents 22e when the tool 28 is inserted into the keyway 22d to secure the tool 28 to the mount. The engagement of the projections with the grooves or detents 22e provides a resistance against inadvertent detachment of the tool 28 from the mount 22, i.e. when the wearer of the prosthesis 10 is engaged in vigorous activity such as table tennis.

Although the mount 22 is described above as being formed from a single piece of rigid plastic material, it will be appreciated that the mount 22 may be formed of two, or more, pieces of rigid plastic material either joined together or individually secured to the sleeve 12.

Tools 28 according to embodiments of the invention utilise a common mating interface 30 for engagement with the mount 22. A preferred mating interface 30 is shown in figure 4. The mating interface 30 is defined by an elongate plate 30a that comprises three evenly spaced spigots 30b that project from one side of the elongate plate 30a and extend longitudinally therealong. The other side of the elongate plate 30a comprises a plurality of holes therein, preferably three, within which are contained respective magnets 32. The wall thickness of the elongate plate 30a in the region of the holes is nominally 0.5mm to ensure that the magnetic properties of the magnets are not blocked by the material of the mount 22. The mating interface further comprises an arcuate cut-out 30c therein on the same side as the spigots 30b and located at one longitudinal end thereof. The arcuate cut-out 30c receives an elongate member therein for engagement with the keyway 22d of the mount 22.

In use, the spigots 30b of the mating interface 30 are aligned with the slots 22e of the mount 22. This action also causes alignment of the magnets 26, 32 to secure the mating interface 30 to the mount 22 through magnetic attraction. The elongate member received within the arcuate cut-out 30c of the mating interface 30 extends into the keyway 22d of the mount 22 to prevent lateral and rotational movement of the mating interface 30 relative to the mount 22.

A tool 28 can be attached to the mount 22 by generally aligning the spigots 30b of the mating interface 30 with the slots 22e of the mount 22. The tool is then guided into the correct position by way of magnetic attraction between the mount 22 and the mating interface 30. To remove the tool 28, the user disengages the mating interface 30 from the keyway 22d to permit removal of the tool 28 from the mount 22. Another aspect of the invention, as illustrated in figure 5, relates to a method of manufacturing prostheses 10. Such a method comprises: i) cutting one or materials to size including an outer layer of material 14, an inner layer of material 16 and a support material 20, as each previously described above; ii) overlaying each of the cut materials; iii) heating the assembly of cut materials at a temperature of 100 to 130 degrees Celsius and for a duration of 6 to 12 seconds; iv) wrapping the assembly of cut materials around a mandrel; iv) allowing the assembly of cut materials to cool on the mandrel; and v) removing the assembly of cut materials from the mandrel.

The outer layer of material 14, inner layer of material 16 and support layer of material 20 are secured either in sheet form or on a roll. The cutting step requires that the relevant material type is laid flat on a planar surface or jig. To secure accuracy of the cutting step, a high accuracy cutting technique is employed such as use of a laser cutter. Use of a laser cutter also helps prevent frayed ends of the material due to the high temperature of the laser melting the edges of the cut material piece. Use of a laser cutter also allows for repeatable dimensions of the cut material piece through use of a computer program. Such a computer program allows the laser cutter operator to upload a design file and position that design file multiple times on a representative sheet of material. It is thus possible to maximise use of the material by strategically planning where each material piece to be cut is located. Different design files are required for left and right handed prostheses 10. Depending on the materials chosen, the cut pieces may need to be cut in a particular manner to ensure that the sleeve 12 is able to stretch laterally with respect to a wearer's residual limb but not axially.

The inner layer of material 16 is provided with a thin strip of Velcro ^® hooks orientated longitudinally. The outer layer 14 of material is provided with two fat strips of Velcro ^® loops orientated laterally. Each of the Velcro ^® components is prepared in advanced by cutting a larger piece of material to size. Prior to attaching the Velcro ^® components to the inner and outer layers of material, the Velcro ^® components are aligned to a selected feature of the inner and outer layers of material. The Velcro ^® components are sewn to the respective inner 14 and outer 16 layers of material using a conventional sewing machine, or manually. Once the Velcro ^® components are sewn to the inner layer of material 14 and outer layer of material 16 respectively, a heat activated adhesive is applied to the inside of the outer layer of material 16. The adhesive is allowed to dry and bond to the outer layer of material 16. If silicone strips are to be applied to the inner layer of material in order to provide a high coefficient of friction surface that resists longitudinal movement of the prosthesis 10 relative to the user's residual and proximal limbs, the silicone strips are prepared at this point of the manufacturing process. The inner layer of material 14 is laid flat on a surface such that it is facing upwardly. A pre-prepared silicone mix is applied to the inside of the inner layer of material 14 in two groups of four horizontally aligned strips. The groups of silicone strips are separated by the axis A-A through the assembly of cut materials. Each silicone strip in a group is vertically spaced from adjacent silicone strips. The groups of silicone strips are located towards the end of the inner layer of material that will ultimately form the proximal end of the prosthesis 10.

At this stage, one or more string like materials, or laces or wires, is applied to the support layer of material 20. The string like materials are an integral part of the constrictor 28 referred to above. The string like material may, or may not, require threading to a spool prior to use. The string like material is wound on the spool. The spool is secured to a portion of the prosthesis through use of adhesive and the string like material is threaded through a plurality of holes and channels in the support layer of material such that the string like material is at least partially located at what would, in use, be the outside of the support layer of material such that when tension is applied to the string like material by winding it more around the spool, a part of the prosthesis 10 is reduced in diameter to secure it to a portion of the user's residual or proximal limb. The spool may also be attached to another part of the prosthesis 10.

After preparation of each of the inner layer of material 14, outer layer of material 16 and support layer of material 20, the inner layer of material 14 and outer layer of material 16 are aligned and tacked together with the support layer of material sandwiched therebetween. Alignment is achieved by matching geometric shapes and features that are common among the inner layer of material 14, outer layer of material 16 and support layer of material 20. The edges of the inner layer of material 14 and outer layer of material 16 are aligned at this stage of the manufacturing process and cotton tape, or similar, is used to bind the edges of both layers of material 14, 16 together. This creates an assembly of cut materials.

The assembly of cut materials is placed in a flat bed heat press that is pre-heated to between 100 and 130 degrees Celsius. Such a flat bed heat press has upper and lower plates with either the upper or lower plate being moveable relative to the other. The moveable plate is moved into contact with the assembly of cut materials and a pressure is applied. The assembly of cut materials is removed from the flat bed heat press after the necessary heating time. The applicant has found that the material requires heating for between 25 - 30 seconds when heated by way of a flat bed heat press. This period of time is sufficient to activate the EVA or polyester applied to the inside of the inner layer of material 14 and activate the heat activated properties of the support layer of material 20. In other embodiments the assembly of cut materials may be placed in an oven, or other heat source, without application of pressure. The heating time is thus dependent on the heat source and other factors.

Once the assembly of cut materials is removed from the flat bed heat press it is immediately wrapped around a mandrel conforming to the desired internal shape of the prosthesis, i.e. a portion of an arm or a leg. The prosthesis can be held in place around the mandrel using the Velcro ^® components, or manually. As the materials cool they retain their shape as defined by the mandrel. Once sufficiently cooled, the resulting sleeve 12 is removed from the mandrel. The sleeve 12 is allowed to cool for a minimum of fifteen minutes.

The distal end of the resulting sleeve 12 comprises an end tab 12d, or tongue, that, in use, defines the socket 18. The socket 18 is formed by the end tab 12d being bent from an orientation in which it is substantially aligned with the axis A-A of the sleeve 12, to an orientation in which the end tab 12d folds back on itself. The end tab 12d is secured in this position by way of one or more fasteners (not shown) that engage with the end tab 12d and the sleeve wall 12c.

Although not shown in the figures, an optional embodiment of the invention 100 may be of modular construction. In such an embodiment 100, a sleeve 102 is formed from several distinct material elements, i.e. plurality of cuffs 102a, 102b, 102c and a splint 102d at a distal end of the sleeve 102. One cuff 102a is positioned at the proximal end of the sleeve 102. A further two cuffs 102b, 102c may be positioned between the distal and proximal ends of the sleeve 102. Each cuff 102a, 102b, 102c is connected to the splint 102d by way of a fixing known in the art, i.e. a buckle or Velcro. Each cuff 102a, 102b, 102c is also optionally provided with a constrictor (not shown) for tightening the respective cuff 102a, 102b, 102c around a user's residual limb. The splint 102d acts as a socket for receiving the user's residual limb. The cuff 102a at the proximal end of the sleeve 102 is attached to the splint 102d by an extensible strap 104, or other extensible object, such that the length of the sleeve 102 can be varied to fit users of varying ages and whom are subject to varying degrees of limb amputation.

All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of this disclosure. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may vary. In each of the figures, like numerals represent like items throughout the figures.

From the foregoing it will be appreciated that, although specific embodiments of the present disclosure have been described herein for purposes of illustration, various modifications and combinations may be made without deviating from the spirit and scope of the present disclosure. For example, although various embodiments are described in the application of insurance coverage, the apparatus and methods described herein may also be applied to other applications. The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.