US 20070055384 A1
An attachment system secures a residual limb to an artificial limb in a comfortable and substantially non-rotational manner. The attachment system offers proximal anchoring of the residual limb in a hard socket, by connecting a side surface of a residual limb liner to the side surface of the socket. Preferably, this connection is accomplished using an extension member extending from the liner through a portion of the socket interior, through the socket wall, and attaching to a latch mechanism. The preferred attachment system requires no clearance in the bottom of the socket well because neither the extension member nor the latch mechanism is located between the distal end of the residual limb/liner and the bottom of the well. The attachment system is preferably disposed entirely along the side of the limb and the side of the socket.
1. An attachment system for a prosthesis comprising:
a prosthesis having a socket with a side wall surrounding and defining an interior well for receiving a user's residual limb, the socket having a proximal end, a distal end, a midway location halfway between said proximal end and said distal end, and a longitudinal dimension between said proximal end and said distal end;
a roll-on liner adapted to attach to a user's residual limb by surrounding the residual limb, the roll-on liner being received in the socket;
an extension member passing from the roll-on liner through an aperture in the socket side wall between the proximal end and the midway location and connecting to a lock that is outside the socket between the proximal end and said midway location.
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10. An attachment system for a prosthesis, comprising:
a liner adapted to fit over the residual limb of a user, said liner having a proximal region and a distal end, and an outside surface adapted to extend circumferentially all the way around the residual limb;
a strap secured to the proximal region of said liner's outside surface, said strap extending towards the distal end of said liner;
a socket for fitting over said liner and said residual limb, said socket having a proximal end and a distal end, a midway location half way between the proximal end and the distal end, an inside surface, and an outside surface;
an aperture in said socket for allowing said strap to pass from the inside surface of the socket to the outside surface of the socket, said aperture being placed between the proximal end and said midway location on said socket; and
a lock mechanism on the outside surface of said socket for receiving and securing said strap.
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16. An attachment system for a prosthesis, comprising:
a liner adapted to fit over the residual limb of a user, said liner having a proximal region and a distal end, and an outside surface adapted to extend circumferentially all the way around the residual limb;
a socket for fitting over said liner and said residual limb, said socket having an interior well defined by a sidewall, and a socket proximal rend, a socket distal end, and a socket midway location half way between said proximal end and said distal end;
a strap secured to said the proximal region of the liner, said strap extending towards the distal end of said liner and into said interior well;
a lock mechanism on said sidewall between said midway location and said proximal end of the socket for receiving and securing said strap, so that the prosthesis is suspended from the liner by the strap.
17. The attachment system of
This application is a continuation of, and claims priority of, U.S. patent application Ser. No. 10/746,208, filed Dec. 23, 2003, entitled Attachment System For Prosthesis, issuing as U.S. Pat. No. 7,077,868 on Jul. 18, 2006, which is a continuation-in-part of U.S. Non-Provisional patent application Ser. No. 09/972,729, filed on Oct. 4, 2001, entitled “Attachment System for Prosthesis,” issued on Dec. 23, 2003 as U.S. Pat. No. 6,666,894, which claims priority of U.S. Provisional Patent Application Ser. No. 60/238,301, filed on Oct. 4, 2000, entitled “Attachment System for Prosthesis,” wherein the above applications are incorporated herein by this reference.
1. Field of the Invention
The present invention relates generally to prosthetics, and, more specifically to an attachment system used in the donning/doffing of a socket onto a residual limb. The present invention more particularly relates to an attachment system that requires little or no clearance inside the socket between the socket and the residual limb, that controls rotation of the prosthesis, and that may be used with a suction-fit socket system. The invented attachment system extends from the side of a liner on the user's limb, through an aperture in the socket, to the outer side of the socket, substantially proximal on the limb and on the socket relative to conventional more “distal” attachment devices. Therefore, the invented attachment may properly be called an exterior, proximal attachment device for a prosthesis.
2. Related Art
For years, many different methods have been used to retain or “suspend” a prosthetic limb on an amputee's residual limb. Gravitational and other forces, for example, from movement of the limbs, tend to cause separation between the prosthetic limb and the patient's residual limb during use. This happens, for example, during the swing phase of gait, when a prosthetic leg is additionally subjected to centrifugal forces. Patients have routinely worn a variety of belts, straps, cuffs, and harnesses to retain their prosthetic limbs against separation from the limb during these periods. However, such devices are often inconvenient and may tend to cause chafing against the patient's body, giving rise to sores and abrasions.
The manner in which an artificial limb is suspended and/or attached to the residual limb determines the amount of control an amputee has over the prosthesis. Therefore, by improving suspension/attachment without adding weight and excessive mechanism, the amputee may obtain improved comfort, convenience, and suspension mobility.
A common approach to tackling this problem has led to the design of a roll-on suction liner, which is rolled onto the residual limb and attached at its distal end to a socket or artificial limb. The liner, which is usually fabricated from silicone, or some other gel form, fits snugly over the residual limb, preferably completely covering the distal end of the residual limb and extending for at least several inches to cover the entire circumference of the proximal region of the residual limb. The liner, in turn, is enveloped, especially at its distal end, by the socket of the prosthesis, which is also called a “hard socket.” A suction fit is preferably formed between the hard socket and the liner. This suspension method is very advantageous for the amputee. It gives the amputee the ability to better control the prosthesis and provides for useful sensory or proprioceptive feedback. Suction suspension also makes a prosthesis feel lighter, compared to other forms of suspension. Unfortunately, only a small percentage of amputees can successfully and comfortably wear a liner without another form of suspension. Therefore, the socket liner is typically equipped with a detachable component, at its distal end, which mates with a locking device in the interior of the socket at the bottom of the interior space or “well.” This system secures the distal end of the residual limb/liner to the distal end of the artificial limb socket well, and, hence, is called a “distal attachment.” The locking device in the distal end of the socket well typically employs a spring-loaded clutch mechanism or a pin-lock mechanism. The component on the distal end of the liner is typically a cylindrical barb-shaped structure or frictionally-retained pin.
One problem associated with such designs is the tugging or pull on the distal end of the limb. Most of these locks are not air tight, thus allowing air to flow into the hard socket and to eliminate the “suction.” When this happens, the only suspension is the pin, which is a traction suspension, rather than suction. In cases where prosthetic socks are worn outside the liner, there is a risk the user's limb will become trapped in the socket if the sock is caught in the locking device. In these incidents, most patients are forced to make emergency trips to their practitioner to remove the prosthetic. Also, the locking device and attachment component cooperate in such a way to permit the barb or pin to lock in a plurality of longitudinal positions, which affects the overall length of the prosthesis. This can make it difficult for the patient to consistently achieve the same prosthetic configuration when the residual limb and the artificial limb are articulated. It should be further noted that, by weight of the lock being added at the distal end of the residual limb or near the distal end of the socket, this can make the prosthetic device feel heavier because of a “lever arm” effect, than if the same weight were placed more proximally. Additionally, many amputees, whether because of the length of their residual limb or their height, do not have room in the suction liner-socket-prosthesis combination for a distal locking mechanism. Or, additionally, use of a distal lock may limit what other prosthetic components that patient may use.
Despite the large number of suspension options available, none of the above-mentioned devices act to eliminate rotation between the hard socket and the suction liner. In an attempt to alleviate the rotation problem, a design called a “quad socket” has been used for many years. The quad socket is shaped in a square manner more than a cylindrical manner, and forcing the “cylindrical” limb to fit tightly in this square receptacle makes the prosthesis less apt to rotate on the limb, much as if you made a wheel square. Unfortunately, this is not a very comfortable position for the limb. Today, there has been a trend toward more naturally-shaped sockets, making rotation control even more difficult.
Therefore, there is still a need for an improved attachment system for prosthetics. Also, there is a need for improving retention of the stump in the socket without sacrificing the patient's comfort and without comprising on expense, weight and simplicity of use of the prosthesis. There also is a need for improving rotation control, which will improve the patient's overall comfort and agility.
The present invention is an attachment system and methods for connecting a prosthesis to a residual limb of the user. Preferably, the attachment system extends from the side surface of a liner on a residual limb to the outside side surface of a hard socket fitted around the liner and limb. Preferably, the attachment system includes a strap system that connects to the outer side surface of the liner to the socket, wherein said strap extends into the socket along a portion the limb, and through an aperture in the sidewall of the socket. Preferably, the strap further extends to a buckle or other latch mechanism connected to the outer side surface of the socket, typically about midway or more, proximally, on the outside surface of the socket. The externally mounted buckle is easily reached and maintained by the user, and easily retrofit as an add-on feature to existing hard sockets. In this way, a combination of the invented prosthetic attachment system and suction fit provide superior retention of the artificial limb on the user.
The preferred strap system includes a disk member or “umbrella” that may be adhesively secured to the surface of the liner, and an elongated strap that extends distally from the umbrella and longitudinally a short distance along the side surface of the limb. The strap may be secured to the umbrella in such a way that its exact angle relative to the limb's longitudinal axis may be adjusted as desired and then locked in place, for example, by tightening of a bolt. The lock is preferably a buckle-style latch mechanism, with a spring-biased member and one or more sharp edges, that frictionally engage transverse detents located between transverse raised ridges on the strap's surface. Thus, the strap is inserted into the buckle to the extent desired by the user, and, in a ratchet-like action, the sharp edges wedge into the transverse detents and secure the strap from being pulled out or away from the buckle. Thus, the strap is anchored in the buckle, and the socket is held closely on the residual limb until the user chooses to unbuckle the buckle.
The especially preferred embodiment includes a duel strap and buckle system wherein one strap and one buckle are located on the medial surface of the liner and socket respectively and one strap and one buckle are located on the lateral surface of the liner and socket respectively. The especially preferred embodiment also includes the invented strap and buckle system wherein said strap may have a “nipple” shaped tab extension at its most distal end to facilitate the strap through the buckle. Also, the underside of the said strap may have a small grooved channel at its distal end in order to feed the strap over a rivet in the base of the buckle. The especially preferred buckle may include a spring-biased member with one or more sharp edges, that frictionally engage transverse detents located between transverse raised ridges on the strap's surface. In order to remove said strap from said buckle, the user pulls the distal end of the buckle away from the socket.
Therefore, the prosthetic attachment system is easily accessible, effective, simple, and easy to use. The versatility and simplicity, and non-interfering design of the invented prosthetic attachment system helps provide reliable and comfortable suspension for an artificial limb on a great number of persons with limb deficiency.
Referring to the Figures, there is shown one preferred embodiment and the especially preferred embodiment, but not all embodiments, of the present invention, which is referred to herein as an attachment system. In this Description and the Claims, the term “proximal” means toward the center/torso of the body, and so toward the top/upper end of the liner and prosthetic device. Thus, in the case of a prosthetic device for a person's leg, “proximal” would mean nearer or toward the upper thigh and trunk. “Distal” means away from the center/torso of the body, and so the regions of the liner or prosthetic device farther out from the trunk, farther out on the leg.
The preferred buckle 26 or latch mechanism of the invented attachment system includes base 10, which is mounted on the external surface of the hard socket 12 by means of a rivet 20, glue or other fastener, or it may even be molded integrally with the socket 12. The buckle 26 is positioned proximally higher up the socket than conventional “distal” locks that are mounted near the distal end of the socket, typically at the bottom of the inside “well” of the hard socket 12. Connected to base 10 are a lever 11 and pin 11′ with e-clips 11″, which together create a biased system for receiving and capturing strap 22, as seen in
Liner 16 may be a custom or a pre-manufactured liner as described in the Related Art section above. Examples of currently-available conventional liners are ICEROSS, ALPHA, LUXURY LINER, ALPS, SILIPOS (all trademarks). Modern urethane liners are especially preferred.
Strap 22 is connected at its proximal end to liner 16, preferably by an umbrella 18 or other fixture or bracket. The umbrella 18 may be glued to the liner, as seen in
The strap 22 is attached to the umbrella 18, for example, with a 10/24-spanner bolt or screw. The screw is then tightened down to the umbrella 18, rather than allowing the strap 22 to pivot around the screw. This results in the strap 22 being adjustable, allowing the user or prosthetist to move the strap 22 and then lock it into the optimum position, even if the strap 22 or lock mechanism have been attached to their respective structures in less-than-perfect position or location.
When hard socket 12 is installed on the residual limb, it extends up over and around liner 16 and umbrella 18, as shown in
Strap 22 is preferably sufficiently rigid, sufficiently long, and is positioned so that, upon the limb/liner being inserted into the socket, the strap naturally tends to slide to and through the aperture15, to the buckle 26, and through the buckle 26 with little or no need for the user to thread or pull the strap 22 through the aperture 15 or buckle 26. A prosthetist will be able to adjust the strap and/or buckle locations and aperture size to enable this smooth movement and latching of the strap in the buckle. Optionally, the socket wall surface, on the interior or exterior, may be contoured to facilitate and direct the strap.
The release button of the buckle 26 is buckle lever 11, which features sharp edge 13, as shown in
After mounting of the base 10 of the buckle 26 onto the socket 12, the umbrella 18 onto the liner 16, and strap onto the umbrella 18, the roll-on prosthetic liner 16 of choice is applied to the patient. The patient can then step into the hard socket 12 and engage the attachment system, by inserting the strap 22 through the aperture 15 and into the buckle 26. This procedure may be used in the retrofitting of the attachment system to an existing prosthetic.
If a new prosthetic is being created, the liner 16 is applied to the patient, and the ideal location for the umbrella 18 is marked on liner 16. A mold over the patient's limb and liner 16 is then taken. After the mold and liner 16 are removed, the umbrella 18 is then attached to the liner 16 in the location marked. From the mold the hard socket 12 is created, and the base 10 of the lock mechanism is attached in the proper location on the outside of hard socket 12, and then the aperture 15 is created in hard socket 12 as above.
The aperture 15 or any other opening through the socket preferably may be easily sealed by a gel suction wrap/cover, or other air-tight wrap or plug that preferably encases the lock mechanism and aperture. This allows and maintains a “suction” fit between the socket and the liner that improves the function of the prosthetic.
The above attachment system was fit to three test patients. All three of these patients utilized ALPHA™ liners in a normal manner. The locking tab was attached to the ALPHA™ liners in a normal manner. Two of these patients were unilateral transtibial amputees, and one patient was a unilateral congenital above-knee amputee. The above-knee amputee was a congenital amputation resulting from PFFD, and his amputation level was consistent with a knee disarticulation level. All three of these patients either demonstrated problems with conventional distal pin-lock systems, or, in the case of the transfemoral amputee, did not have sufficient room to install any of the distal locking mechanisms currently on the market. These patients were using the prosthetic lock suspension according to the present invention on their prosthesis on a daily basis. These patients were all experimentally fit in June of 2000 and no problems were encountered with mechanical failures or with patient acceptance or satisfaction. We continue to monitor these patients at 2-3 week intervals.
One may see, after reviewing the disclosure of this Description and the Drawings, that the invented attachment system tends to prevent rotation of the prosthesis on its longitudinal axis (axis extending between its proximal end and distal end) relative to the amputated limb. By providing one of the invented side-located, “proximally-located” attachment systems, such rotation is limited or prevented. This is because strap extends from a fixed anchor location on the side of the liner/limb to a fixed anchor location on the side of the socket, thus connecting those two fixed locations together at substantially a fixed distance apart, thereby not allowing the anchor location on the socket to rotate any significant distance away from the anchor location on the liner. Although one of the invented attachment systems is preferred, more than one may possibly be used, for example, at two positions around the side of the limb/socket, as described below in the Especially Preferred Embodiment section.
Other benefits of the attachment system include comfort and ease of use. The preferred attachment system is simple to use, each to reach, and requires a minimum of dexterity. The externally-mounted lock mechanism eliminates the jamming of conventional distal locks often caused by a sock worn over the roll-on liner.
While a ratchet-style buckle and strap combination is preferred, other releasable attachments and fasteners may be used. For example, extension members other than a flat strap with detents may be used, such as a cord(s), loop(s), tab(s), or other rigid or flexible extension members. Latch mechanisms other than a buckle may be used, such as a hook(s), clip(s), snap(s), or other devices that adjustably or non-adjustably grip the extension member. The connection between the extension member and the latch mechanism is preferably, but not necessarily, adjustable. This permits the user or the prosthetist to manipulate the connection for optimum use and comfort, either by lengthening or shortening the connection or by pivoting or otherwise moving the location of the extension member or latch mechanism.
In the Description and Claims, the term “lateral” means on/toward the outer surface or region of the body, and therefore, on/toward the outer surface or region of the apparatus that is installed on the human body. Thus, a lateral surface of the liner or socket is an outer side surface, away from the inner or medial plane of the body. See lateral surfaces 101, 101′ of the liner and socket, respectively, in
The especially preferred embodiment comprises one or more attachment systems having improved straps and latch mechanisms that make donning and doffing the prosthesis more convenient and comfortable. The embodiment of
The especially preferred strap 122 has a “nipple” shaped tab extension 114, or other tapered, narrow tip, at its distal end. The extension 114 preferably has a width less than half of the width of the strap122. The extension facilitates the strap122 from the inside of the socket 12 to the socket's external surface and through the buckle 126 (see
In order to install the socket 12 on the residual limb, the user places the two straps 122 inside the socket 12 and then feeds them through two apertures 115 located medially and laterally in the socket's 12 side wall, as seen in
The especially preferred method for releasing the straps 122 from the buckles 126, is for the user to pull up on the distal end of each lever 111 to pivot the lever 111 into a raised position as shown in
While lateral and medial positions for two strap and buckle combinations are preferred, other locations and other numbers of strap and buckle combinations are also possible. The buckles in
Preferably, the prosthesis attachment system comprises the invented extension member and latch system, with or without the aid of suction between the liner and the socket, but no other straps or attachments. Preferably, there is no belt or strap extending to encircle part of the user's body, and preferably no attachment between the distal end of the limb/liner and the bottom of the well of the socket.
Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the broad scope of this disclosure and the following claims.