EP2753288B1

EP2753288B1 - Biometric forearm crutch with an ulnar recess

Info

Publication number: EP2753288B1
Application number: EP12769046.9A
Authority: EP
Inventors: Thomas Hügle
Original assignee: Universitaetsspital Basel USB
Current assignee: Universitaetsspital Basel USB
Priority date: 2011-09-09
Filing date: 2012-09-07
Publication date: 2017-03-01
Anticipated expiration: 2032-09-07
Also published as: WO2013034748A1; EP2753288A1

Description

The invention relates to a crutch according to the preamble of claim 1.
Such a crutch for a forearm for carrying at least a fraction of the weight of a person usually comprises a longitudinally extending member having a floor-engaging first free end, via which - upon walking - at least a fraction of the gravitational force of said person is induced into the floor, a handle connected to said longitudinally extending member, which handle is designed to be grasped by said person in order to support said person via the crutch, as well as a cuff connected to said longitudinally extending member, wherein said cuff comprises a contact surface, on which the forearm rests upon normal use of the clutch through said person.
Document DE-U1-29822843 discloses a crutch comprising all the technical features set out in the preamble of claim 1. Long term use of these kind of crutches is typically required by patients having a chronic impairment of the musculoskeletal apparatus such as osteoarthritis, rheumatic diseases or spine disorders. At their upper part - as mentioned above - forearm walking crutches have a cuff being adapted to embrace the forearm in order to gain stability. In the case of permanent use, forearm crutches can lead to skin bruises, pain and possibly nerve compression over the ulna bone or elbow of the respective forearm. This is due to the prominent anatomic position of the ulna bone, which has no surrounding soft tissue cushioning, when in contact with the inner side of the shell.
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In the anatomical position (i.e. when the palms of the hands face forward) the ulna is located at the side of the forearm closest to the body (the medial side), the side of the little finger. The corresponding bone in the leg is the fibula.
Thus, the problem underlying the present invention is to provide a crutch of the aforementioned kind that is more suitable for long term use.
This problem is solved by a crutch having the features of claim 1.
According thereto, the contact surface comprises a particularly vertical recess that is designed to receive the ulna bone of said forearm when said handle is held by a hand belonging to said forearm, in order to minimize the pressure acted on the ulna bone by said cuff.
The recess takes the form of a groove that extends in an extension direction along the whole cuff, from an upper edge of the cuff towards a lower edge of the cuff (with respect to a state in which the longitudinally extending member or said extension direction runs essentially parallel to the vertical).
Particularly, the recess may comprise either a V-shaped, a rectangular or a rounded cross sectional contour in a plane running perpendicular to said extension direction of the recess/groove.
With respect to a plane running across the (longitudinal) extension direction of the recess, the contact surface preferably comprises a concave shape, so as to encompass the forearm when said handle is held by a hand of said forearm (i.e. a hand of the person physically connected to the forearm). Further, the cuff comprises an outer side facing away from the contact surfaces that preferably comprises a corresponding convex shape, so that the cuff is essentially U-shaped in cross section.
Preferably, said recess - starting from the upper edge of the cuff - tapers towards the lower edge. Possible values for the width of the recess at the upper edge range from 3 cm up to 5 cm, wherein possible values for the width of the recess at the lower edge of the cuff range from 1 cm up to 3 cm.
Furthermore, the recess of the cuff preferably comprises a depth between 0.2 cm and 2 cm.
Generally, the cuff can be considered to consist of a first and a second cuff part or portion, which parts are integrally formed to one another along a midline of the cuff, which particularly forms a mirror symmetry axis. Preferably, said ulna-sparing recess is located between 5° and 45°, particularly between 10° and 45°, laterally of said midline, i.e., is arranged in one of the cuff parts, so as to account for the spatial position of the ulna, when the crutch is grabbed as intended by the person.
In order to strengthen the structure of the cuff, it may comprise a bulge on the outer side corresponding to the recess on the contact surface (inner side) of the cuff, so that the cuff has essentially a constant thickness, even in the region of the recess/groove.
In a variant of the invention, the cuff comprises a cushion, which forms the contact surface that comprises the recess, i.e., the recess is formed in the cushion.
Preferably, this cushion is fastened to an inner side of a (rigid) shell of the cuff serving as a retainer for the cushion. Like the cuff before, the inner side of the shell is concave while an outer side of the shell facing away from said inner side is shaped convex.
In one embodiment, the cushion is preferably permanently fastened to said shell, for instance be means of an adhesive.
Alternatively, the cushion may be releasably fastened to the shell by means of at least one pocket of the cushion, for instance, which at least one pocket is designed to receive at least a region of the shell in order to fasten the cushion to said shell.
Preferably, the cushion may comprise a leather or a plastic (or any other suitable material), wherein eventually the cushion may comprise a covering (e.g. out of a leather or a plastic) that defines an interior space that may be filled with a suitable padding.
The shell or cuff (in case no cushion is present) is preferably formed out of a plastic or a wood.
Preferably, the handle for holding the crutch with a hand comes off the longitudinally extending member and may be integrally formed with the latter or welded to it (other connecting means involving e.g. screws or rivets are also conceivable). Likewise, the cuff may be integrally formed with the longitudinally extending member or connected to it by some fastening means like for instance screws or rivets. Other fastening means are also conceivable.
Further, the longitudinally extending member preferably comprises a second free end opposite the first free end to which the cuff is preferably connected for supporting the forearm of the person grasping the handle with a hand belonging to the supported forearm. Particularly, said handle is connected to the longitudinally extending member between the cuff and the first free end of the longitudinally extending member.
Further features and advantages of the invention shall be described by means of detailed descriptions of embodiments with reference to the Figures, wherein

Figure 1: shows a view of a forearm comprising ulna and radius as well as the hand belonging to the displayed forearm;
Figure 2: shows a plan view onto a front side of an upper part of a forearm crutch according to the invention having a vertical ulna-sparing recess located laterally from a midline of a cuff of the crutch;
Figure 3: shows a plan view onto the top side of a forearm crutch according to the invention; and
Figure 4: shows a plan view onto the top side of yet another forearm crutch according to the invention having a cushion comprising an ulnasparing recess.

Figure 1 shows a perspective view of a forearm F of a person being connected to an associated Hand H of the person, wherein the forearm F comprises the ulna U and the radius R, both of these bones being connected to the humerus H'.
Figure 2 shows a crutch 1 according to the invention. The crutch 1 comprises a longitudinally extending member (rod) 20 that comprises a first free end 21 which upon walking with the crutch 1 is made to repeatedly rest on a floor 23 in order to support (at least a part of) the weight of the person using the crutch 1.
The crutch 1 further comprises an essentially U-shaped cuff 10 that is connected to a second free end 22 of the longitudinally extending member 20, which cuff 10 is designed to encompass and support a forearm F in the region of its ulna U, when the person grasps a handle 30 of the crutch 1 protruding from said longitudinally extending member 20 below the cuff 10 and uses the crutch 1 as intended.
The cuff 10 comprises a concave inner side 10a forming a contact surface for the forearm F as well as a convex outer side 10b facing away from said inner side 10a.
Further, the cuff 10 comprises an upper edge 41 extending essentially along the horizontal when the crutch 1 is in an upright (vertical) position, and a lower edge 42 that also extends essentially along the horizontal with respect to said upright position.
Further, the cuff 10 may be regarded as consisting of two cuff parts 101, 102 (e.g. in the form of a quarter-shell, respectively) being integrally connected to each other along a (fictitious) midline M.
Now, in order to reduce the focal pressure of the ulna bone U, a recess 100 extending in the form of a groove (notch) along an extension direction R from the upper edge 41 to the lower edge 42 is provided in the contact surface (inner side) 10a, wherein the extension direction R runs essentially along the vertical in said upright position of the crutch 1. The recess 100 is designed to receive the ulna U in order to distribute the pressure over a larger area of the contact surface 10 of the cuff 10. The reduced focal pressure on the ulna bone U then prevents skin bruises, pain or nerve compression. Preferably, the recess 100 is tapered, comprising a width B at the upper edge 41 of the cuff between 3cm and 5cm, as well as a width C at the lower edge 42 of the cuff between 1cm and 3cm. Preferably, the depth D of the recess 100 ranges between 0.2 and 2 cm.
As shown in Figure 2 to 4, the groove 100 is preferably positioned in the first cuff part 101 (right hand side of the cuff 10), i.e., it is preferably arranged such that a normal N of a (fictitious) open top surface S of the groove 100 and a further normal N' of the contact surface 10a coming off the midline M encloses an angle A between 5° and 45°, particularly between 10° and 45°.
The groove 100 may result in a bulge 110 projecting from the outer side 10b of the cuff 10 according to Figure 3, so as to ensure that the cuff 10 comprises essentially a constant thickness over the whole contact surface 10a yielding a good stability of the cuff 10.
Figure 4 finally shows a modification of the cuff 10 shown in Figure 3, wherein the contact surface 10a of the cuff 10 is now formed by an inner side 12a of a cushion 12 facing the forearm F, which cushion 12 butts with an outer side 12b of the cushion 12 against a concave inner side 11 a of a (U-shaped) rigid shell 11 of the cuff 10, wherein said shell 11 further comprises a convex outer side 11 b forming now the outer side 10b of cuff 10. The shell 11 serves as a retainer of said cushion 12, wherein the cushion 12 can be either attached non-releasably (i.e. permanently) to the shell 11, for instance by means of an adhesive, or releasably, for instance by jacketing the shell 11 with lateral pouches (pockets) of the cushion 12.
In Figure 4 - in contrast to Figure 3 - the recess 100 is formed entirely in the cushion 12, wherein the shell 11 of the cuff 10 now (merely) serves as a provider of structural stability for said cushion 12.

Claims

Crutch for a forearm of a person for supporting said person, comprising:
- a longitudinally extending member (20) having a floor-engaging first free end (21),

- a handle (30) connected to said longitudinally extending member (20), which handle (30) is designed to be manually graspable by said person, and

- a cuff (10) connected to said longitudinally extending member (20), which cuff (10) forms a contact surface (10a) that is designed to support said forearm, when said handle (30) is held by a hand (H) associated to said forearm (F),
characterized in that,
the contact surface (10a) comprises a recess (100) that is designed to receive the ulna bone (U) of said forearm (F), when said handle (30) is held by said hand (H) associated to said forearm (F), wherein said recess (100) is a groove formed in said contact surface (10a), wherein said groove (100) extends along an extension direction (R) from an upper edge (41) of the cuff (10) to a lower edge (42) of the cuff (70).
Crutch according to claim 1, characterized in that the recess (100) comprises a V-shaped, a rectangular or a rounded cross sectional contour in a plane running perpendicular to said extension direction.
Crutch according to claim 1 or 2, characterized in that the contact surface (10a) is concave in a plane running perpendicular to the extension direction (R).
Crutch according to one of the claims 1 to 3, characterized In that the recess (100) tapers towards the lower edge (42) of the cuff (10), wherein particularly the width (B) of the recess (100) at the upper edge (41) of the cuff (10) lies between 3 cm and 5 cm, and wherein particularly the width (C) of the recess (100) at the lower edge (42) of the cuff (10) lies between 1 cm and 3 cm.
Crutch according to one of the preceding claims, characterized In that the recess (100) comprises a depth (D) between 0.2 cm and 2 cm.
Crutch according to one of the preceding claims, characterized in that the cuff (10) comprises a first and a second cuff part (101, 102), which cuff parts (101, 102) are integrally connected to each other along a midline (M) of the cuff (10), wherein said recess (100) is located laterally of said midline (M), particularly by an angle (A) between 10° and 45°.
Crutch according to one of the preceding claims, characterized In that said cuff (10) comprises a bulge (110) on an outer side (10b) of the cuff (10) facing away from the contact surface (10a) of the cuff (10), which bulge (110) runs along the recess (100), in order to strengthen the cuff (10) in a region of the recess (100).
Crutch according to one of the claims 1 to 6, characterized In that the cuff (10) comprises a cushion (12) forming said contact surface (10a).
Crutch according to claim 8, characterized in that the cushion (12) is fastened to a shell (11) of said cuff (10).
Crutch according to claim 9, characterized in that the cushion (12) is permanently fastened to the shell (11), particularly by means of an adhesive.
Crutch according to claim 9, characterized in that the cushion (12) is fastened to the shell (11) by means of at least one pocket of the cushion (12), which at least one pocket is designed to receive at least a region of the shell (11) in order to fasten the cushion (12) to said shell (11).
Crutch according to one of the preceding claims, characterized in that the handle (30) protrudes from the longitudinally extending member (20).
Crutch according to one of the preceding claims, characterized in that the longitudinally extending member (20) comprises a second free end (22) opposing the first free end (21) of the longitudinally extending member (20).
Crutch according to claim 13, characterized in that the cuff (10) is connected to the longitudinally extending member (20) at the second free end (22).
Crutch according to one of the preceding claims, characterized in that said handle (30) is connected to the longitudinally extending member (20) between the cuff (10) and the first free end (21) of the longitudinally extending member (20).