NL2016047B1

NL2016047B1 - CMC I orthosis.

Info

Publication number: NL2016047B1
Application number: NL2016047A
Authority: NL
Inventors: Robin Engelshoven Wouter
Original assignee: We Design B V
Priority date: 2015-08-21
Filing date: 2015-12-29
Publication date: 2017-03-13
Also published as: NL2016047B3

Abstract

Orthosis for immobilizing a carpometacarpal joint of a thumb (CMC I) of a hand, comprising a joint supporting part (1) and a holding part (2), wherein the joint supporting part (1) comprises at least one anatomically shaped rigid ring-shaped element (3) configured to be slid onto the thumb to enclose part of a thenar eminence (T) of the thumb, wherein the holding part (2) comprises a rigid stabilizing part (4) that is fixed at a first position to the joint supporting part (1) and is configured to reach sideways along a first side of the hand to engage a pinky side of the hand, wherein the holding part (2) also comprises an adjustable stabilizing part (5) configured to reach along a second side of the hand to connect a second positon of the joint supporting part (1) to a distal end of the rigid stabilizing part (4).

Description

P109078NL10

Title: CMC I orthosis

The invention relates to an orthosis for immobilizing a carpometacarpal joint of a thumb (CMC I) of a hand comprising a joint supporting part and a holding part.

An orthosis can be indicated for a person suffering from pain in the thumb’s carpometacarpal joint (CMC I joint), due to for example rhizarthrosis, as the orthosis can support and immobilize the painful joint.

Such orthoses are generally known from prior art, for example from DE 19511116. Therein, a thumb orthosis is revealed, comprising a body retaining its form and having a passage through which a thumb can be put. During wear of the orthosis, the body encloses the thumb on part of its length and is attached to the hand via an elastic retaining band. The body distally encloses a part between thumb and middle hand, and proximally encloses the thumb close to the saddle joint. On the palm side, the body has a large support surface to support the ball of the thumb. Such an orthosis us usually constructed to immobilize the CMCI joint when the thumb is in its rest position (i.e. extended) as in fig. 1 of DE19511116. A problem with such a prior art system is that an elastic retaining band, for example closed with hook-and-loop fasteners, is easily prone to wear resulting in a diminishing efficiency of the orthosis. Furthermore, when a wearer of the orthosis for example wants to wash his hands, either the elastic retaining band becomes wet, and it takes a relatively long time to dry, or the wearer should take off the orthosis. When the body of the orthosis is made of a thermoplastic, it can be unpleasant to wear such an orthosis on warm days because of sweating of the hand under the orthosis, for example under the enlarged thumb’s ball supporting surface. Unpleasant wearing also leads to a diminished efficiency, as a patient can easily be tempted to leave out the orthosis when it hinders.

It is an aim of the present invention to solve or alleviate one or more of the above-mentioned problems. Particularly, the invention aims at providing a relatively durable and long-lasting orthosis. It is also an object of the invention to provide a efficient, comfortable orthosis. The invention particularly aims at providing an orthosis which is pleasant and nice to wear in substantially all situations, and preferably has an exclusive appearance.

To this aim, according to a first aspect of the present invention, there is provided an orthosis characterized by the features of claim 1.

Advantageously there is provided an orthosis for immobilizing a carpometacarpal joint of a thumb of a hand, comprising a joint supporting part and a holding part, wherein the joint supporting part comprises at least one anatomically shaped rigid ring-shaped element configured to be slid onto the thumb (towards the palm of the hand) to enclose part of a thenar eminence of the thumb. The holding part comprises a rigid stabilizing part that is fixed at a first position to the joint supporting part and is configured to reach sideways along a first side of the hand to engage a pinky side of the hand. The holding part also comprises an adjustable stabilizing part configured to reach along a second side of the hand to connect a second positon of the joint supporting part to a distal end of the rigid stabilizing part.

It has been found that in this way, improved immobilization of the CMC I joint can be achieved in a highly comfortable manner. The one or more ring-shaped elements can firmly engage the hand near the thumb (just below the thumb) to block CMCl movements, in cooperation with the holding part which firmly engages the other (pinky) side of the hand. Preferably, the orthosis is configured for only immobilizing that particularly CMCl joint, that is, it does not substantially affect operation of other thumb joints such as the metacarpophalangeal joint.

In this application, the term “anatomically shaped” regarding the ring-shaped element particularly means that the element is shaped to engage and closely fit to the respective section of the hand, with the thumb in an initial rest-position. Also, herein, “rigid” particularly means that the respective element does not bend or otherwise deform during any normal thumb muscle loading or finger movements, experienced when the orthosis is worn.

Preferably, the rigid stabilizing part includes a rigid section that is anatomically shaped to closely fit onto or around the pinky side of the hand, enabling further comfort and additional stability.

In an embodiment, the rigid parts (rigid stabilizing part and each ring-shaped element) can be made in a relatively slender design, e.g. out of wire or wire-shaped material. As an example, in a non-limiting embodiment a width of a rigid stabilizing part and a thickness of a ring-shaped element may be 1 cm or smaller. Also, preferably, the rigid stabilizing part is or includes an elongated section, extending over a side of the hand when worn.

Similarly, a said adjustable stabilizing part can be made of slender design. It can be or include a relatively thin flexible band, e.g. having a thickness of about 1-3 mm, and a width of about 1-2 cm.

For example, the holding part may comprise a rigid stabilizing part and an adjustable stabilizing part (e.g. a strap), and the rigid stabilizing part may be made of a material that is different from a material of which the adjustable stabilizing part is made, the choice of the material for each part can be optimally adapted to the function of each part, such that the orthosis is a durable, wear-resistant orthosis, which does not loose its efficiency due to wear, and which remains pleasant to wear in substantially all situations.

In a preferred embodiment, the rigid stabilizing part is made of a material retaining its form during operation (when worn). This ensures a lasting stability and thus efficiency to the orthosis.

In a more preferred embodiment, the at least one ring-shaped element is made of a metal or a metal alloy, for example of gold, silver, bronze, titanium or an alloy thereof. Metal or a metal alloy can be easily shaped and adapted to a person’s specific anatomy during manufacture, according to well known techniques, while retaining its form over a long period. Metal is generally relatively well supported by a person’s skin, and diminishes the risk of sweating. Moreover, a ring-shaped element in a metal or metal alloy, for example in silver, gives the orthosis a especially nice visual aspect, which can be an important trigger to wear the orthosis permanently.

More preferably, rigid the stabilizing part is made of a metal or a metal alloy, for example of gold, silver, bronze, titanium or an alloy thereof. On top of the above-mentioned advantages for a metal ring-shaped element, which are also valid for a metal stabilizing part, a stabilizing part made of a metal or a metal alloy improves the stability and thus efficiency of the orthosis.

Preferably, adjustable stabilizing part is adjustable to pull the second positon of the joint supporting part and the distal end of the rigid stabilizing part toward each other, thereby setting or improving CMCl joint stabilization. For example, the adjustable stabilizing part may be configured to adjust part of its length (shortening and lengthening), such as in case of an adjustable strap.

Advantageously, the adjustable stabilizing part is made of a flexible non-elastic material, for example of nylon, or woven fabric, a non woven fabric, a textile material or the-like. A flexible material can adapt itself to a person’s hand, and does not hinder use of other fingers than the thumb of the hand. It preferably does not exercise pressure on ligaments or metacarpal bones of the hand, when worn. A non-elastic material has the advantage to be less prone to wear due to intensive use.

In an preferred embodiment, a first end of the rigid stabilizing part is connected with the at least one ring-shaped element, in particular undetachably connected. This ensures stability of the orthosis. At the same time, the for example undetachable connection between the rigid stabilizing part and the at least one ring-shaped element provides a support for the thumb’s ball. According to an embodiment, a said undetachable, firm, connection can be achieved by welding or soldering, or by making the elements in one piece with another.

Alternatively, the first end of the stabilizing part can also be detachably connected with the at least one ring-shaped element, for example via corresponding engaging elements (e.g. a releasable click or clamp connection, screw or bolting means or the-like).

Also, in addition or alternatively, the first end of the stabilizing part can also be pivotally connected to the at least one ring-shaped element, e.g. via a suitable pivot connection, allowing more comfort to a user.

Advantageously, during wear of the orthosis, the rigid stabilizing part rigid is configured to extend along the palmar side of the hand. For example, it can overly a palm of the hand, bend over an ulnar side of the hand, and overly an ulnar sided dorsum of the hand . This structure allows a reliable, comfortable stabilization of the at least one ring-shaped element by building up a counter-pressure without hindering movements of the other four fingers nor of the other two joints of the thumb, i.e. the MCP I and IP I joints.

More advantageously, the orthosis can be configured such that during use, the distal end of the rigid stabilizing part is located substantially centrally on the dorsum of the hand. An extension on the dorsum of the hand provides a good stabilization of the orthosis. However, a stabilizing part extending over the centre of the dorsum can hinder or even cause pain during movement of other fingers of the hand, especially of the index finger.

Preferably, the distal end of the stabilizing part is provided with a guiding aperture, allowing passage of the adjustable stabilizing part to better retain the orthosis on the hand. Other connections between the adjustable stabilizing part and the end of the rigid stabilizing part are possible as well, for example clamping means.

In an advantageous embodiment, the adjustable stabilizing part is a V-folded strap. A first connection of a first end of the strap with the at least one ring-shaped element and a second connection of a second end of the strap with the at least one ring-shaped element may e.g. be spaced-apart on the at least one ring-shaped element. Also, an intermediate portion of the strap can be passed through the strap guiding aperture. In this way the tension in the adjustable stabilizing part is spread over three different spaced-apart points, two on the at least one ring-shaped element and one on the distal end of the stabilizing part, which improves the stability of the orthosis.

The adjustable stabilizing part is preferably an adjustable, flexible non-elastic strap. This improves wearing comfort. Also, the length of the strap can be adjusted to allow the orthosis to be set to the shape of a hand, or to a swelling of a hand, for example due to exercise or to heat.

Advantageously, the at least one ring-shaped element is substantially oval-shaped, e.g. to closely fit a part of a thenar eminence at the basis of the thumb.

More advantageously, a proximal opening side of the at least one ring-shaped element can be larger than a distal opening side of the at least one ring-shaped element. This shape follows the anatomy of the basis of the thumb, and thus gives an improved support to the thumb.

Good results are achieved in case the orthosis includes a succession of at least two ring-shaped elements. This enlarges the support surface of the orthosis while keeping only a minimal skin covering by the orthosis, thus improving comfort during wear of the orthosis.

It is more preferred that a major axis of a proximal ring-shaped element is larger than a major axis of a distal ring-shaped element. This feature again makes it possible to better follow the anatomy of the hand’s basis and improves the efficiency of the orthosis.

According to a second aspect of the present invention, there is provided an orthosis characterized by the features of claim 17. This orthosis leads to advantages mentioned above, and can particularly provide an exclusive appearance as well as durability and comfort to user.

The present invention will be further elucidated with reference to figures of an exemplary embodiment of the invention. Therein, corresponding elements are designated with corresponding reference signs.

Figure 1 shows a bottom view of a preferred non-limiting embodiment of an orthosis according to the invention;

Figure 2 shows a perspective bottom view of the embodiment of

Figure 1;

Figure 3 shows a radial side of a left hand wearing the embodiment of Figure 1;

Figure 4 shows a dorsal side of a left hand wearing the embodiment of Figure 1;

Figure 5 shows a side view of the embodiment of Figure 1;

Figure 6 shows a perspective front view on a joint supporting part of the embodiment of Figure 1;

Figure 7 shows a palmar side of a left hand wearing the embodiment of Figure 1;

Figure 8 shows an ulnar side of a left hand wearing the embodiment of Figure 1;

Figure 9 shows a back view of the embodiment of Figure 1;

Figure 10 shows a side view of the embodiment of Figure 1; and

Figure 11 shows a view similar to Fig. 3, of a right hand wearing the orthesis.

The drawings show a preferred embodiment of an orthosis. Figure 1 is a bottom view. In this context, the wording “bottom view” means “as seen from a point on a forearm”. The exemplary embodiment described here is an orthosis for immobilizing a carpometacarpal joint of a thumb (CMC I) of a hand, for example of a left hand as shown. The present orthosis can also be worn on a right hand (as is shown in Figure 11). The embodiment of the orthosis in Figure 1 comprises a joint supporting part 1 and a holding part 2. The joint supporting part 1 of the orthosis is of slender design and comprises at least one ring-shaped element 3 (two in this example) configured to enclose/grasp part of the ball (thenar eminence) T of the thumb (see Figures 3 and 7). As follows from the drawing, during use, the joint supporting part 1 as such does (substantially) not engage the thumb finger part (starting from the metacarpal section) itself. The same holds for the remaining parts 4, 5 of the present orthosis.

The embodiment of the orthosis in Figures 1 and 2 comprises a succession of two ring-shaped elements 3a, 3b, which, in this example are connected to each other (or fuse with one another) on a first side S (in the example a bottom side S) of the joint supporting part 1.

In the present example said bottom side S faces away from the index finger during use. Also, in the present example, the two ring-shaped elements 3a, 3b enclose an arcuate slit 3c there-between. In the drawings, the arcuate slit 3c extends along the hand part located between thumb and index finger when worn (see Fig. 7).

Alternatively, the depicted orthosis can be worn such (e.g. on a right hand, see Figure 11) that the arcuate slit 3c between the ring-shaped elements faces downwards, and that the first side where the ring-shaped elements are connected/fuse is located between the hand part located between thumb and index finger when worn (i.e. after 180 degrees turn of the orthosis with respect of the orientation shown in see Fig. 7). This allows for particular comfort.

Alternatively, the orthosis can also comprise a succession of three, or more, ring-shaped elements.

The at least one ring-shaped element 3 is preferably made of a material retaining its form, preferably made of a metal or a metal alloy, for example of gold, silver, bronze, titanium or an alloy thereof. It will be clear to a person skilled in the art how to produce such an element, for example by forging, or by casting the element. The element can also be created through 3D printing.

The present holding part 2 comprises a rigid stabilizing part 4 and a flexible strap 5. The present rigid stabilizing part 4 is also of slender design, having an elongated and locally gently curved shape.

The rigid stabilizing part 4 is fixed at a first position (in this case a palmar position) to the joint supporting part (namely to a first of the two ring-shaped elements 3). The present rigid stabilizing part 4 is configured to reach sideways along a first side of the hand (the palm side, in this example) to engage the pinky side (ulnar side) of the hand. Particularly, the present rigid stabilizing part 4 includes a curved section 4a for engaging or enclosing the pinky side of the hand, see Figures 2, 4 and 7, the rigid stabilizing part 4 having a distal section 4b which extends along par of the opposite side (dorsal side) of the hand (see Fig. 4)

The holding part 2 also comprises an adjustable stabilizing part 5 configured to reach along the second side of the hand (dorsal side in the example) to connect a second positon of the joint supporting part 1 to the distal section 4b of the rigid stabilizing part 4.

Preferably, the rigid stabilizing part 4 is made of a material that is different from a material of which the adjustable strap 5 is made. The rigid stabilizing part 4 can advantageously be made of a material retaining its form, preferably of a metal or a metal alloy, for example of gold, silver, bronze, titanium or an alloy thereof. The rigid stabilizing part 4 can he produced using the same manufacturing process as a process used to make the ring-shaped elements 3, for example simultaneously.

The strap 5 can preferably be made of a flexible non-elastic material, for example of nylon, or woven fabric, a non woven fabric, or a textile material. A proximal (i.e. first) end 6 of the rigid stabilizing part 4 may be connected with the at least one ring-shaped element 3, in particular undetachably connected, for example by soldering the first end 6 to the ring-shaped element 3. In the example, the proximal end 6 of the rigid stabilizing part 4 is located at a position about or near the middle between a top U and bottom S of the first ring-shaped element 3a of the orthosis (see Fig. 9, 10). The connection between the rigid stabilizing part 4 and the ring-shaped element(s) may be an immovable connection, or alternatively e.g. a pivot connection, the latter allowing pivot movement of the rigid stabilizing part 4 with respect of the ring-shaped element(s) for additional ease of putting on and taking off the orthosis. A distal (i.e. second) end 7 of the rigid stabilizing part 4 may be provided with a strap guiding aperture 8. In the example, this guiding aperture 8 is a cured slit, defined between two curved wall sections of the end 7 of the rigid stabilizing part 4.

Also, as follows from the drawing, in this example, the distal section 4b of the rigid stabilizing part 4 as such may have an open structure, e.g. being a (relatively flat) tapered or diverging section 4b with a curved end 7, and e.g. including a central aperture 4c; in this example, said central aperture 4c and strap guiding aperture 8 are separated by a curved wall section 4d.

As follows e.g. from Figure 3, the joint supporting part 1 preferably comprises the at least one ring-shaped element 3, configured to enclose part of a thenar eminence T of the thumb. A first connection 13 of a first end 14 of the strap 5 with the at least one ring-shaped element 3 is preferably spaced-apart on the at least one ring-shaped element 3 from a second connection 15 of a second end 16 of the strap 5. In the present example, said first connection 13 of the strap is located at or near an top side of the first ring shaped element 3a, whereas said second connection 15 of the strap is located at or near the bottom side S (see Figures 4, 6, 9, 10).

It is preferred that the strap 5 is an adjustable strap. To this aim, such a first connection 13 may for example comprise a succession of two ring-like elements or a helically wound metal wire, attached to the joint supporting part 1, around which a first end 14 of a strap 5 may be wrapped or folded back. Optionally, the folded first end 14 may then be held together to the strap 5 by another ring-like element 20, or a clamping device, or for example a hook-and-loop fastener.

The second connection 15 of the second end 16 of the strap 5 may be of a similar type to the first connection 13, or may be different. In this embodiment, the second connection 15 comprises a small bridge-like element, attached to the joint supporting part 1, through which a second end 16 may be put. The second end 16 is thickened, for example by putting glue on it or by adding a metal element at the extremity of the end 16, such that the end 16 is held back by the bridge-like element. Alternatively, only one end of the strap may be connected with the at least one ring-shaped element 3, and the other end of the strap 5 can be connected with the stabilizing part 4. Another possibility may be to connect both ends 14 and 16 of the strap 5 to a single connection element on the ring-shaped element 3.

During wear of the orthosis, a distal end 7 of the stabilizing part 4 can preferably be located substantially centrally on the dorsum 12 of the hand (as in Fig. 4), for example overlying the metacarpal bones III and/or IV, but it might also only overlie the metacarpal bone V, or extend further over the centre of the dorsum 12.

It is advantageous that the strap 5 is a V-folded strap, for example with connections 13 and 15 to the at least one ring-shaped element 3, as shown in Figure 3. An intermediate portion 17 of the strap 5 may then be passed through the strap guiding aperture 8 at the distal (free) end 7 of the rigid stabilizing part 4, allowing gliding of the intermediate portion 17 of the strap 17 through the aperture 8 and an adjustment of both parts of the strap simultaneously. Alternatively, the strap 5 may be replaced by two shorter straps, of which one end of each is attached to the end 7 of the stabilizing part 4, and the other ends to the connections 13 and 15.

The at least one ring-shaped element 3 may be substantially ovalshaped (see e.g. Fig. 5), or another shape closely fitting the hand part at the thenar eminence T. In an embodiment including a succession of at least two ring-shaped elements 3a, 3b, a major axis Xa of a proximal ring-shaped element 3a can advantageously be larger than a major axis Xb of a distal ring-shaped element 3b.

As is shown in more detail in Figure 6, the joint supporting part 1 may comprise a succession of two ovally shaped elements 3a, 3b, which are connected to each other at a basis of the oval shape. In the example, the ring elements 3a, 3b mutually enclose a curved slit 3c. A proximal opening side 18 of the at least one ring-shaped element 3, in this case of the proximal element 3a, may be larger than a distal opening side 19 of the same ring-shaped element 3a. In this embodiment, this is not the case for the second distal element 3b, for which a proximal opening side 18b is substantially of the same size as a distal opening side 19b.

Figure 7 shows a palmar side of a left hand wearing the embodiment of Figure 1, and Figure 8 shows an ulnar side of a left hand wearing the embodiment of Figure 1. Both Figures, in combination with Figure 4, show how during wear of the orthosis, the stabilizing part 4 overlies a palm 9 of a hand, bends over an ulnar side 10 of the hand, and overlies an ulnar sided dorsum 11 of the hand. The stabilizing part 4 may be slightly bended such that it can neatly fit the shape of a palm of a hand, as can also be seen in Figure 1. The bending of the stabilizing part 4 over the ulnar side 10 of the hand can be located substantially around a middle of the metacarpal bone V, or lower, but in between the CMC V joint and the MCPV joint.

Figure 9 shows a back view of the embodiment of Figure 1 and corresponds to the position of the embodiment in Figure 7. Figure 10 shows a side view of the embodiment of Figure 1, and similarly corresponds to the position of the embodiment in Figure 8. In Figure 9, it can also be seen that a proximal opening side 18 of the proximal ring-shaped element 3a, may be larger than a distal opening side 19 of the same ring-shaped element 3a, and that this is not the case for the distal ring-shaped element 3b, as explained also in Figure 6.

The depicted orthosis is easy to handle, can be made lightweight and is very comfortable to the user. Also, particularly in case it is made of a metal or alloy, it has an appealing appearance.

It should be clear to the person skilled in the art that the invention is not limited to the embodiment described above. Many alternatives are possible within the scope of protection as formulated in the claims hereafter.

For example, as already mentioned, the orthosis can be configured to be worn on a left hand (as shown in Figures 3, 4, 7) or to a right hand (as shown in Figure 11). In case a configuration having a plurality of ring-shaped elements, fused together at an end, it may be beneficial to wear the orthosis such that the fused ring-sections are located between the hand part located between thumb and index finger when worn (as is shown in Figure 11, i.e. opposite to the embodiment shown in Fig. 7).

The strap can for example also be made of leather or different material. Connections between the different parts can have various embodiments as well.

Claims

An orthosis to immobilize a carpometacarpal joint of a thumb (CMC I) of a hand, comprising a joint supporting part (1) and a holding part (2), wherein the joint supporting part (1) comprises at least one anatomically shaped rigid annular element (3) adapted to be slid on the thumb to enclose a part of a thumb ball (T) of the thumb, the holding part (2) comprising a rigid stabilizing part (4) fixed to a first position supporting the joint part (1) and is arranged to extend sideways along a first side of the hand to engage on a little finger side of the hand, the holding part (2) also including an adjustable stabilizing part (5) vessel adapted to extend along a second side of the hand to connect a second position of the joint supporting member (1) to a distal end of the rigid stabilizing member (4).

Orthosis according to claim 1, wherein the adjustable stabilizing part is an adjustable band (5),

Orthosis according to any one of the preceding claims, wherein the at least one annular element (3) is made of a metal or a metal alloy, for example of gold, silver, bronze, titanium or an alloy thereof.

Orthosis according to any one of the preceding claims, wherein the rigid stabilizing part (4) is made of a metal or a metal alloy, for example of gold, silver, bronze, titanium or an alloy thereof.

Orthosis according to any one of the preceding claims, wherein the adjustable stabilizing part (5) is made of a flexible non-elastic material, for example of nylon, a woven fabric, a non-woven fabric, a textile material.

Orthosis according to any one of the preceding claims, wherein a first end (6) of the rigid stabilizing part (4) is connected to the at least one annular element (3), in particular inseparably connected, the rigid stabilizing part (4) ) is, for example, welded or soldered to, or made in one part with, the at least one annular element (3).

An orthosis according to any one of the preceding claims, wherein the rigid stabilizing part (4) is adapted to reach a palm side (9) of the hand when worn.

An orthosis according to any one of the preceding claims, wherein during wear of the orthosis the distal end (7) of the rigid stabilizing member. (4) is located substantially centrally on the back (.1.2) of the hand,

An orthosis according to any one of the preceding claims, wherein the distal end (7) of the rigid stabilizing part (4) is provided with a conductive opening (8).

An orthosis according to any one of the preceding claims, wherein the adjustable stabilizing part (o) is a band folded in V-shape.

The orthosis according to claim 10, wherein a first connection (13) of a first end (14) of the band (5) with the at least one annular element (3) and a second connection (15) of a second end (16) ) of the tire (5) with the at least one annular element (3) are spaced apart on the at least one annular element (3), and wherein an intermediate portion (17) of the tire (5) through a bandieiden.de opening (8) of the rigid stabilizing part (4).

An orthosis according to any one of the preceding claims, wherein the at least one annular element (3) is substantially oval-shaped.

An orthosis according to any one of the preceding claims, wherein a proximal opening side (18) of the at least one annular element (3) is larger than a distal opening side (19) of the at least one annular element (3).

An orthosis according to any one of the preceding claims, wherein joint-supporting part comprises a sequence of at least two annular elements (3a, 3b), for example only two annular elements (3a, 3b) enclosing a slot (3c) therebetween.

The orthosis of claim 13, wherein a major axis (Xa) of a proximal annular element (3a) is larger than a major axis (Xb) of a distal annular element (3b).

An orthosis according to any one of the preceding claims, wherein the adjustable stabilizing part (5) is adapted to reach a backside of the hand when worn.

17. Orthosis to immobilize a carpometacarpal joint (CMC I) of a thumb of a hand, for example an orthosis according to any one of the preceding claims, comprising a joint supporting part (1) and a holding part (2), the holding part (2) 2) comprises a rigid stabilizing part (4) fixed at a first position on the joint supporting part (1) and adapted to extend sideways along a first side of the hand to engage a little finger side of the hand, wherein the joint-supporting part (1) comprises a sequence of at least two annular elements (3a, 3b), being anatomically shaped and adapted to be slid onto the thumb to enclose said first carpometacarpal joint.

An orthosis according to claim 17, wherein the annular elements (3) are made of a metal or a metal alloy, for example of gold, silver, bronze, titanium or an alloy thereof, the rigid stabilizing part (4) preferably being made of the same material as the annular elements,

The orthosis according to claim 17 or 18, wherein the annular elements (3a, 3b) enclose an arcuate slot (3c) therebetween.