Patent Publication Number: US-2022226184-A1

Title: Compression Stocking with Adjustable Compression Pressure

Description:
The invention relates to a compression stocking with adjustable compression pressure for therapeutic compression of a limb, particularly a leg. 
     Chronic venous insufficiency (CVI) is a condition of the (lower) limbs. The condition is related to an insufficiency (i.e. a functional or physical defect) of one or more veins in the limbs. The insufficiency is usually caused by failure or impaired function of the venous valves. The most extreme form of CVI symptoms is a venous (leg) ulcer. For treatment of such a venous insufficiency, and also for other venous or arterial problems for that matter, use is often made of compression therapy. This involves arranging an elastic stocking around the limb which is causing complaints, or wrapping the limb in bandages. The elastic compression stocking fits very tightly round the limb so as to be able to exert a sufficiently great compression thereon. Bandages must be pulled very tight in order to be able to exert sufficient compression on the limb. For older patients in particular it is often no longer possible, especially in higher compression classes, to pull on these compression stockings themselves or to tighten these bandages sufficiently themselves. A nurse or similar career will have to step in to put on and take off the stockings or wrap the bandages for the patient. 
     Because the compression therapy is only effective when sufficient compression is exerted on the limb, the degree of compression must be monitored periodically (up to a few times a day). If the compression is too low, a new stocking must be put on or the limb must be re-bandaged. This is an inefficient and expensive activity when having to be done by a career. Even if the patient is able to do it themselves, it puts a lot of strain on him or her. There is therefore a need for a support stocking which can be put on more easily, without a career being needed to do so. 
     A further drawback of the known elastic stocking or the known bandages is that the degree of compression is inaccurate. It can in fact not be measured, or hardly so, which compression (pressure) is being exerted on the limb. This also makes it difficult to measure the effect of the compression therapy. 
     The distribution of the compression pressure over the surface of the limb is further inaccurate. What happens here is that after some time, for instance after a few hours, the pressure exerted on the limb has decreased because the limb has decreased in size. The support stocking or bandages can then become loose locally, which can diminish the therapeutic effect. 
     Support stockings wherein use is made of an adjustable compression pressure are per se known in the field. In a determined type of support stocking with adjustable compression the stocking is provided with an inflatable pressure chamber whereby the compression exerted on the limb can be varied by inflating the pressure chamber. Examples of such a type of support stocking are described in patents WO 03/007855 A1 and DE 10 2008 029 289 A1. Such an inflatable support stocking is per se advantageous because it is much simpler to put on the support stocking, since inflation need not be carried out until after the stocking has been put on. A further advantage is that the pressure (compression) is controllable in principle. A further advantage is that, if the limb were to shrink at a certain point and the support stocking were thereby to become looser, the stocking can be made tighter again in simple manner by additionally inflating the pressure chamber. 
     The known support stockings however do have a number of drawbacks. A drawback is for instance that, as a result of the very low overpressures which are generated in the stocking (characteristically 30-60 mm Hg), it is difficult to have a properly functioning valve mechanism (valve) with which the loss of air pressure is limited to a minimum or is avoided over the course of time (for instance during the course of the day). A further drawback is that the known valves whereby the support stocking is connected to the outside world are often complex and/or protrude too far outside the stocking, this making them inconvenient for the patient and clothing. 
     Known from WO 2012/142155 A2 is a therapeutic compression stocking consisting of a first stocking element (calf wrap) which is arranged around the lower leg of a patient and a second stocking element (foot wrap) which is arranged around the foot of the patient. Provided in both stocking elements is a pressure compartment (bladder) which can be inflated with air. 
     The pressure compartment however has limited dimensions and extends only at the position of the calf (i.e. the rear side of the lower leg) and the heel (i.e. the underside of the foot). No pressure compartment is present at the position of the other parts of the leg with which the compression stocking is in contact, for instance the front side of the lower leg and the sides of the foot. A different pressure will be exerted on the leg at positions where no pressure compartment is present than on parts where the pressure compartment is present. The known compression stocking therefore does not exert a uniform pressure. This can greatly reduce the effect of the compression stocking and/or the comfort for the patient. 
     The fact that a pressure compartment is not present over the whole contact surface of the compression stocking with the lower leg, and variations in compression thus occur over the contact surface, is not the only reason for the reduced effect of the stocking and/or degree of comfort for the patient. These drawbacks occur all the more because the known compression stocking is further provided with a large number of through-holes which form an open connection between the outside air and the leg. No compression of the leg whatsoever thus occurs in the large number of areas where such a through-hole is present. The effectiveness of the known compression stocking at preventing the above stated complaints is therefore limited. 
     It is an object to provide an improved compression stocking wherein at least one of the above stated drawbacks is obviated. 
     It is also an object to provide a compression stocking which has such a simple construction and/or can be manufactured in such cost-effective manner that it can be replaced with a new support stocking after one use or only a limited number of (for instance two or three) uses. 
     It is also an object to provide a compression stocking which enables an improved compression therapy and/or can increase comfort for the user. 
     At least one of the objectives is achieved in a compression stocking with adjustable compression pressure for therapeutic compression of a leg, the compression stocking comprising:
         a first stocking element to be arranged around the lower leg;   a second stocking element to be arranged around the foot of the leg, wherein the second stocking element is attached to the first stocking element or formed integrally thereon at an angle;       

     further comprising a pressure compartment to be filled with air up to the adjustable compression pressure and extending in both the first and the second stocking element, and configured to extend all the way around the periphery of at least a part of the lower leg in use in order to exert a homogenous pressure on the at least one part of the lower leg all the way around; 
     a valve mechanism connected to the pressure compartment, wherein the valve mechanism preferably comprises a closable passage between the pressure compartment and the outside air, wherein the valve mechanism comprises:
         a valve seat attached to the stocking element;   a valve lid attached to the valve seat or formed thereon, wherein the passage extends through the valve seat and the valve lid;   a valve provided in the passage and embodied to be movable between a closing position, in which the valve closes the passage airtightly, and a position allowing passage, in which the valve leaves the passage at least partially open; and   at least a connecting part between the valve and the valve seat and/or the valve lid for flexible attachment of the valve to the valve seat and/or the valve lid, wherein the at least one connecting part is embodied to urge the valve toward the closing position under bias.       

     The pressure compartment can further be embodied to wholly surround the lower leg in peripheral direction in the situation in which the stocking is being worn so that the pressure compartment extends over the whole contact surface (whole in the sense of the peripheral direction of the lower leg in question) of the stocking with the lower leg, and the lower leg encounters an identical pressure over this whole contact surface (since the pressure is the same in the whole pressure compartment, in accordance with Pascal&#39;s law). What this amounts to is that the pressure compartment at the position of the first stocking element extends on the front side, the rear side and on the sides of the lower leg during use. The compression pressure is adjustable by controlling the amount of air introduced into the pressure compartment, but is constant over the whole periphery of the (part of the) leg. This has a positive effect on the uniform compression on the leg, and so on the effect of the compression stocking. The patient further feels no pressure differences over the surface of his or her lower leg, which improves comfort for the patient. In order to exert the correct compression pressure on the foot said pressure compartment extends into the second stocking element, this such that the pressure compartment is situated only on the sides of the foot during use. The pressure compartment has been dispensed with at the position of the sole of the foot and the instep of the foot. By exerting the set compression pressure only on the sides of the foot a superior operation of the compression stocking can be realized. The patient is further able to walk properly with the compression stocking because no pressure compartment is present under the sole and/or the compression stocking is compact enough for shoes or slippers to still be worn over it. 
     In determined embodiments the pressure compartment in the first and second stocking element can further be located over the whole surface of the stocking intended for contact with the leg, with the exception of the surface of the sole and instep. The pressure is thereby homogenous on the leg at every position where the stocking is present. 
     According to further embodiments, the pressure compartment forms one single, uninterrupted space. In determined embodiments there are further no passages such as through-holes between the outer and inner side of the stocking and the like. A uniform distribution of the compressive forces over the contact surface of the support stocking directed toward the lower leg is hereby achieved. The pressure space is further uninterrupted. There are no surfaces present in the contact surface with the lower leg directed toward the lower leg where less pressure or no pressure (i.e. only the ambient air pressure) is exerted on the lower leg (or the foot). 
     In respect of the valve mechanism, it is the case that the provided bias is preferably greater than the force which is exerted on the valve as a result of the pressure difference between the air pressure in the pressure compartment and the outside air pressure. This ensures that the valve always tends to move toward the closing position in order to close the passage airtightly. This means that the compression pressure remains constant (at the correct pressure value) and does not tend to decrease to greater or lesser extent during and after removal of the air pump with which the compression pressure is realized. This improves the operation of the compression stocking. 
     In practice said pressure difference amounts to a maximum of about 80 mm Hg, wherein the more usual pressures lie slightly lower, for instance in the order of magnitude of 30 to 60 mm Hg. These pressures are so low that in known valves without said connecting part they will often be insufficient to make the valve mechanism close. In practice the valve is then sometimes not closed properly, so that air can escape from the pressure compartment and the compression on the limb will become too low at a given moment. In the compression stocking as described here it is thus the connecting part and not primarily the air pressure difference between the pressure inside the pressure compartment and the outside air that ensures that the valve mechanism tends to close. 
     In an embodiment the second stocking element comprises:
         a sole part;   an instep part;   side parts between the sole part and the instep part, wherein the pressure compartment extends in at least one of the side parts.       

     The sole part, instep part and side parts are preferably embodied to be situated under, above and to the side of the foot of the leg in a situation of use. In a further embodiment a pressure compartment is arranged neither in the instep part nor in the sole part. The sole part is used for walking on, and a good contact must be maintained between sole and ground surface. The sole part is preferably manufactured from non-elastic material. This has the result that the one or more pressure compartments of the compression stocking are positioned accurately relative to the different components of the foot in order to be able to exert pressure on the foot in precisely the right area. 
     It has for instance been found by the inventor that it is particularly exerting pressure on  malleolus lateralis  (i.e. the piece of bone (prominence) on the outer side of the leg/the foot, formed by the lower outer end of the fibula protruding laterally outward), optionally also exerting pressure on  malleolus medialis  (i.e. the piece of bone (prominence) on the inner side of the leg/the foot, formed by the lower outer end of the tibia), that produces good results in the treatment of chronic venous insufficiencies (CVI). In preferred embodiments the at least one pressure compartment is therefore located at least adjacently of the  malleolus lateralis , preferably also adjacently of the  malleolus medialis , in a situation of use. Correct dimensioning of the non-elastic sole part enables the pressure compartment to be positioned relative to the foot with such accuracy that the support stocking presses on the  malleolus  exactly at the right position. 
     In further embodiments the instep part is embodied in elastic material. The elastic embodiment enables the compression stocking to already be clamped fixedly to the foot to some extent, which facilitates putting on of the stocking. 
     In a preferred embodiment the second stocking part is embodied to be slidable directly onto the foot, and cannot be opened. The first stocking part can be opened, and can thereby be easily arranged round the lower leg (calf) in fully opened position. The edges of the first stocking part are then fastened to each other, and inflation of the pressure compartment can commence. 
     In determined embodiments the compression stocking has only one single pressure compartment. This has the advantage, among others, that the whole stocking can be inflated via a single valve mechanism and/or that the pressure in the pressure compartment is uniform over the whole stocking. In other embodiments the compression stocking has two or more optionally separated pressure compartments. These pressure compartments are then however in open connection with each other so that the pressure is the same in all pressure compartments, and the same pressure is thus exerted at the position of the pressure compartments over the whole surface that presses against the leg. 
     The pressure compartments can be operated (inflated and deflated) by one single, collective valve mechanism. In further embodiments the pressure compartments however each have their own valve mechanism. 
     In an embodiment the at least one connecting part is embodied to be bent between a starting position, in which the valve is in the closing position, and a bent position, in which the valve is in the position allowing passage, under an external mechanical force. The valve mechanism is here preferably embodied such that the valve is only opened under the influence of the mechanical force. The mechanical force can for instance be produced by a pressing force which is exerted on the valve by the outer end of a pump tube or conduit inserted into the passage. Additional forces, such as an increased air pressure, are thus unnecessary. The connecting part is further embodied such that in the bent position it tends to return to the starting position (in which the valve closes the passage). In a determined embodiment the connecting part is manufactured from elastic material, at least material sufficiently bendable under external force. When the external force is released, for instance because the pump is detached from the valve mechanism, the valve returns to its starting position. 
     In a determined embodiment the compression stocking comprises two or more connecting parts, wherein the valve is disc-like, the connecting parts extend in radial direction relative to the disc-like valve and/or the connecting parts are attached to or formed on the valve at uniformly distributed positions. 
     As already stated above, the external force on the valve can be produced by the outer end of a conduit or the like of a pump with which the pressure compartment can be inflated. In further embodiments an air pump is provided which is configured to inflate the pressure compartment. The air pump comprises a pump tube or pump conduit which can be coupled to the valve lid. The pump tube or pump conduit has a (free) outer end which can be inserted into the passage and is embodied to exert in inserted situation the above stated mechanical force whereby the valve can be pushed from the closing position to the position allowing passage. In determined embodiments the outer end can be clamped fixedly on or otherwise secured in said passage. The outer end is preferably clamped fixedly such that the clamping force is greater than the force exerted by the at least one connecting part on the valve in order to urge the valve back to its starting position. The valve hereby remains opened until the outer end has been removed from the passage again. 
     In determined embodiments a pressure sensor is provided for the purpose of determining a pressure value representative of the pressure in the pressure compartment. The pressure sensor can here be a permanent pressure sensor and/or can be embodied to measure the pressure inside the pressure compartment. The pressure sensor can be an internal pressure sensor which is arranged inside the pressure compartment, for instance integrated with the valve mechanism, but can also be an external pressure sensor which is mounted on the outer side of the pressure compartment and is in pressure connection therewith. In other embodiments the pressure sensor does not form part of the support stocking but is for instance a separate pressure sensor or a pressure sensor which forms part of the air pump. In the latter case the pressure sensor can be embodied to measure the pressure in the pump tube or pump conduit. This pressure measured in the conduit or tube is directly or indirectly representative of the pressure in the pressure compartment. 
     In determined embodiments, wherein the pressure sensor is provided with a display on which the pressure is displayed or wherein the pressure can be shown in other manner, the person inflating the pressure compartment can keep an eye on the pressure during the inflating. The pressure sensor (optionally in combination with a control unit) can be set to generate a visual and/or auditive warning signal at a desired pressure to be set by the therapist. A coloured light signal (for instance via said display and/or via one or more optionally coloured lights, for instance red and green LED lamps) can for instance be generated when the pressure is too low, too high or correct. When the pressure has reached a predetermined desired value, he or she will stop the inflating and remove the pump from the support stocking. The valve will close automatically, and the support stocking is ready for use. In other embodiments this process can be automated. In a preferred embodiment the support stocking and/or the air pump comprises a control unit which is coupled to the air pump and pressure sensor and is configured to control the air pump depending on the measured pressure. The control unit can for instance be configured to increase the pressure in the pressure compartment until a preset maximal pressure value, for instance stored in the control unit or in a separate memory, is reached. 
     Provided in determined embodiments is a memory which is coupled to the pressure sensor and is configured to periodically store measured pressure values. The therapy adherence of the patient can for instance be measured hereby. 
     In determined embodiments, for instance—though not limited to—embodiments in which the pressure sensor is placed inside the pressure compartment, the pressure sensor comprises a wireless communication unit for wirelessly transmitting a pressure signal representative of the pressure in the pressure compartment. The pressure signal can here be representative of the current pressure measured by the pressure sensor and/or of one or more of the measured pressure signals from the memory coupled to the pressure sensor. 
     In a further embodiment the communication unit, and preferably also the pressure sensor and/or the control unit, is configured to be powered only by an external radio frequency signal. They do not have their own power source or energy source, such as a passive tag or an RFID transponder. Such a communication unit can utilize the electromagnetic field of an external reader to induce a current in a coil, with which (a chip in) the communication unit is powered. 
     In order to achieve a good compression on the limb, keep the external dimensions of the support stocking in inflated state limited yet still enable a high degree of comfort for the patient, the compression stocking comprises according to determined embodiments:
         an outer wall with a high modulus of elasticity (E), preferably a modulus of elasticity of at least 50 MPa.       

     The compression stocking preferably comprises an inner wall, directed toward the limb during use, of a flexible material which closely follows the contour of the limb. 
     In a further embodiment the stocking element comprises an outer wall with an elasticity (ε) of a maximum of 5%, preferably a maximum of 2%, when the pressure compartment is inflated to an overpressure of 100 mg Hg. With such an outer wall sufficient compression can be realized without the outer dimensions of the support stocking becoming too great, which would reduce the wearer comfort of the support stocking. 
     In a determined embodiment the stocking element comprises an outer and inner wall manufactured from airtight film, wherein the outer and inner wall are preferably sealed together along their peripheral edges for the purpose of forming the pressure compartment therebetween. In this way a comfortable support stocking can be realized quickly and at relatively low cost. 
     It is otherwise usual also to arrange an additional layer between the compression stocking and the limb. In the case of an ulcer, bandaging is worn underneath the compression stocking. In other cases, a desired thin stocking can be worn underneath it. 
     The material of the inner wall (for instance TPU film) of the compression stocking is preferably chosen such that it does not feel unpleasant on the skin per se. 
     In determined embodiments the stocking element of the support stocking comprises an outer and inner wall manufactured from plastic, particularly thermoplastic polyurethane or polypropylene. The outer wall preferably has a wall thickness of between 100 and 300 μm, and the inner wall a wall thickness of between 50 and 100 μm. This wall thickness for the outer wall provides a good compromise between flexibility and minimal stretch when a TPU film is used. The inner wall should be as thin as possible, while maintaining airtightness and applicability in chosen manufacturing techniques. 
     In determined embodiments the outer wall of the stocking element is provided with a number of stretch-limiting elements configured to limit stretch when the pressure compartment is inflated. A stretch-limiting element can for instance comprise a strengthening thread arranged in or on the outer wall. These are oriented such that stretch in a determined direction can be limited. The strengthening threads can for instance extend in peripheral direction when the stocking element is arranged around the limb. When the stocking element extends vertically, the strengthening threads thus extend in horizontal direction (i.e. the width direction). Expansion in radial directions is limited hereby, so that the dimensions of the support stocking in those directions also remain limited. 
    
    
     
       Further advantages, features and details will be elucidated with reference to the following description of some embodiments thereof. Reference is made in the description to the accompanying figures, in which: 
         FIG. 1  shows a view of a leg provided with the embodiment of a support stocking according to the invention; 
         FIG. 2  shows a view of the embodiment of the support stocking of  FIG. 1  before it is arranged round the leg; 
         FIG. 3  shows a perspective detail view of a valve mechanism according to a determined embodiment; 
         FIG. 4  shows a perspective exploded view of the valve mechanism of  FIG. 3 ; 
         FIG. 5  shows a cross-section through the valve mechanism of  FIG. 4 ; 
         FIG. 6  shows a cross-section through the embodiment of the support stocking of  FIG. 1 , in combination with a pump for inflating the support stocking, in a situation before the pressure compartment is inflated; 
         FIG. 7  shows the cross-section of  FIG. 6  in a situation during inflation; 
         FIGS. 8 and 9  show cross-sections through another embodiment, respectively in the situation before and during inflation, wherein the support stocking is provided with an internal pressure sensor; 
         FIG. 10  shows a top view of the internal pressure sensor of  FIGS. 8 and 9 ; 
         FIG. 11  shows a perspective front view of a further embodiment of a stocking according to the invention, with a first stocking element in opened state; 
         FIG. 12  shows a side view of the embodiment of  FIG. 11  in closed situation; and 
         FIG. 13  shows a side view of a leg provided with a stocking according to the embodiment of  FIGS. 11 and 12  in a situation of use. 
     
    
    
       FIG. 1  shows an embodiment of a support stocking  1  in a situation of use. This embodiment of the stocking covers only the calf of a patient. In other embodiments the foot and/or the upper leg of the patient can however also be covered. In other embodiments the support stocking is arranged round an arm or the like. Support stocking  1  comprises a stocking element  2  which is clamped fixedly around the limb using fastening means  3 .  FIG. 2  shows the fastening means  3  in more detail. 
     In the shown embodiment the stocking element  2  is constructed from a multi-layer film, wherein a pressure chamber or pressure compartment is formed between the layers of the multi-layer film. The multi-layer film can be wrapped around the limb and then be secured, particularly be clamped fixedly, in wrapped state, for instance by attaching a longitudinal edge of the support stocking to another part of the support stocking with fastening means. 
     In the shown embodiment fastening means  3  comprise a number of (i.e. in the shown example five, although this number can vary) fastening tongues  7  which are provided on one side with a strip of hook and loop elements  8 . Tongues  7  are provided along a longitudinal edge  13  of stocking element  2 . A number of hook and loop elements is arranged on the opposite longitudinal edge  12  of stocking element  2 , at positions corresponding with those of tongues  7 . Once stocking element  2  has been wrapped around the leg, it can be clamped fixedly to the leg using the hook and loop elements  5 ,  6  so that the support stocking remains at the desired position. The support stocking need however not be arranged with such force that the therapeutic compression pressure is realized. 
     The therapeutic compression pressure is however realized by inflating the pressure compartment of the support stocking. As already explained above, stocking element  2  comprises a number of layers of film, between which a pressure compartment is formed. Stocking element  2  of the support stocking can for instance be constructed from an outer layer or outer wall  14  and an inner layer or inner wall  15 . The outer and inner wall  14 ,  15  are attached to each other at their peripheral edges (for instance by welding (sealing) them together, which results in the welded seam  16  shown in  FIG. 2 , which extends along the upper side  11 , lower side  10  and longitudinal edges  12 ,  13 ). In this way a pressure compartment  9  is realized between the outer and inner wall  14 ,  15 . This pressure compartment  9  can be provided with air from the outside using a valve mechanism  4  in order to generate a sufficiently high compression pressure in pressure compartment  9  and thus allow the compression stocking to push with sufficient compression pressure against the limb. 
     The compression caused by the pressure in the pressure compartment of the first stocking element and the second stocking element is the same everywhere. This provides for a uniform distribution of the pressure over the whole contact surface of the stocking with the leg, at least at the positions where the pressure compartment is situated. Since the pressure compartment is situated around at least a part of the lower leg, so both on the front side and on the rear side thereof, and at the position of the sides of the foot, the pressure and thereby the compression caused will be the same everywhere in those areas. The patient experiences the same pressure on all sides of the lower leg (i.e. front side, rear side and both sides), which makes the stocking extremely comfortable. 
     Referring to  FIGS. 3-5 , a first embodiment of valve mechanism  4  is first described. Valve mechanism  4  comprises a valve seat  20  attached to outer wall  14  by means of ultrasonic welding. This valve seat  20  comprises a radial flange  21  which provides for a sufficient attaching option of the valve mechanism to outer wall  14 . Radial flange  21  is further provided with an upright, axially extending edge  22  around an opening  25 . Positioned centrally in this opening  25  is a disc-like valve  23 , which valve  23  is held in place by a number of (in the shown embodiment four) connecting parts  24 . These connecting parts extend in radial direction from the centre of valve  23  and form as it were a star-shaped attachment of valve  23  to the rest of valve seat  20 . Valve mechanism  4  further comprises a valve lid  26  attached to the valve seat or formed thereon. This valve lid  26  can be slid between upright edge  22  and be clamped fixedly onto valve seat  20 . This situation is shown in  FIG. 6 . The valve seat and the valve lid lie tightly against each other such that essentially no air can flow via the valve lid and the valve seat into and out of compartment  9 , besides via the passage  29  provided centrally in valve lid  26 . The passage  29  and the valve lid connect to valve  23 , this such that in the starting position (with the valve in the closing position, as shown in  FIG. 6 ) valve  23  fully closes the passage  29  so that no air is able to flow into the pressure compartment or out of the pressure compartment. 
       FIG. 6  further shows how the pressure compartment  9  of the support stocking can be inflated. Use is made for this purpose of the schematically shown pump  40 . This can be any pump, for instance—though not limited to—a diaphragm pump  40 . Pump  40  comprises a pump conduit or pump tube  30  and a pressure sensor  41  connected thereto, with which the pressure inside the pump conduit or tube can be measured. 
     The conduit or tube  30  has a shape and dimensions such that it fits just inside the passage  29  in valve mechanism  4 . When the air compartment has to be inflated, the outer end of the pump tube/pump conduit  30  is displaced in the direction of valve mechanism  4  (direction P 1 ), and the outer end thereof is inserted fittingly into passage  29 . At a given moment the outer end of the pump tube/pump conduit  30  will press onto the upper side of valve  23  and, when pushed further (direction P 1 ), the valve will be pressed downward by the downward mechanical force caused thereby (which is greater than the upward force exerted on valve  23  by the connecting parts), as is shown in  FIG. 7 . In the bent position of connecting parts  24  shown in  FIG. 7  the connecting parts will exert an upward force on valve  23  and will try to push valve  23  back to the starting position shown in  FIG. 6 . The external mechanical force is however greater, and valve  23  remains in the position allowing passage which is shown in  FIG. 7 . Valve  23  then no longer closes the underside of passage  29 . Air can then flow via the pump tube/pump conduit  30  (direction P 2 ) and the opening between connecting parts  24  into pressure compartment  9 . 
     Inflation of the pressure compartment can be done manually, but can also be controlled by a control unit  42  coupled to pump  40  and pressure sensor  41  ( FIG. 6 ). When the pressure gauge or pressure sensor  41  measures the desired final pressure, it transmits a signal to control unit  42 . Control unit  42  stops inflation and the conduit/tube  30  can be pulled out of the passage again. As a result of the construction of the connecting parts they will return from the bent position shown in  FIG. 7  to the starting position shown in  FIG. 6 , so that the valve is returned from the position allowing passage to the closing position. 
     Pressure sensor  41  can also be used for randomly or periodically monitoring the pressure afterwards, for instance after decreasing due to reduced swelling. If the pressure has become too low, control unit  42  generates a signal representative of the fact that the pressure has become too low, on the basis of which a visual and/or auditive warning signal can be emitted and the patient is informed that the stocking should be refilled with air. 
     The shown construction ensures that when pump conduit  30  is removed from passage  29 , valve  23  always ends up back in the starting position (i.e. the closing position) automatically as a result of the forces exerted by the connecting parts  24 . The construction of the valve mechanism is further very simple and can be manufactured in large numbers and at relatively low cost. A further advantage is that the overall thickness of the valve mechanism can remain limited. In the shown embodiment the thickness (d) (see  FIG. 6 ) of the valve mechanism is for instance a maximum of 1 cm, preferably smaller than 0.5 cm. 
       FIG. 2  further shows that a number of stretch-limiting elements  17  is arranged in and/or on the material of the stocking element, for instance in the material of outer wall  14  thereof. When the stocking element is arranged around a limb, the stretch-limiting elements  17  extend in the peripheral direction. These stretch-limiting elements are less elastic (i.e. have a lower elasticity (ε), defined as the ratio between the change in length and the original length of a piece of material) than the material itself, and thus provide for a limitation of the stretch in the direction in which the stretch-limiting elements extend (therefore only in the width direction in the shown embodiment). 
     In the embodiment shown in  FIGS. 6 and 7  the pressure sensor  41  is provided as part of pump  40 . In the other embodiment, for instance the embodiment as shown in  FIGS. 8 and 9 , pressure sensor  50  is arranged inside pressure compartment  9 . More particularly, pressure sensor  50  is integrated with valve mechanism  4 , for instance by mounting the pressure sensor on the underside of valve  23 . In order to ensure that the pressure measured by the sensor can be easily read, the sensor can be provided with a wireless communication unit  51  for wirelessly transmitting a pressure signal representative of the pressure in a supply compartment. This can be the current pressure measured by the pressure sensor at that moment. In the other embodiments, the pressure sensor is however provided with a memory (not shown in the drawings) in which pressure values are occasionally (periodically) stored. These pressure values are thus stored and can be collectively transmitted via a pressure signal to an external receiver (not shown) using the wireless communication unit. 
     Pressure sensor  50  (optionally provided with a memory and optionally provided with a communication unit) is preferably embodied as a passive element, i.e. this sensor does not have its own energy source as power supply but is powered by the electromagnetic radiation, for instance electromagnetic radiation from the receiver. More particularly, use can be made of an RFID tag as shown in  FIG. 10 , whereby information from the pressure sensor can be transmitted wirelessly to an external RFID receiver. 
     A further embodiment is shown in  FIGS. 11-13 . The figures show a stocking  60  comprising a first (upper) stocking element  61  and a second (lower) stocking element  62  formed thereon. The first stocking element  61  is embodied to be arranged around the calf (k) of a leg (b) ( FIG. 13 ), while the second stocking element  62  is embodied to be arranged around the foot (v) of the leg (b). A single pressure compartment  63  is arranged in the stocking. Pressure compartment  63  extends in both the first and the second pressure element  61 ,  62 . More particularly, pressure compartment  63  comprises a first pressure compartment part  75  in first stocking element  61  and two pressure compartment parts  73 ,  74  in second stocking element  62 . All pressure compartment parts are in open connection with each other and can be filled with air via a valve mechanism, preferably a valve mechanism  4  as described above. 
     Second stocking element  62  is attached to or formed on first stocking element  61  at an angle (i.e. angle α,  FIG. 12 , preferably in the range of 60°&lt;α&lt;120°) such that the stocking can be arranged comfortably around the leg and can fulfil its compressing function. 
     In the shown embodiment second stocking element  62  comprises a sole part  69 , an instep part  72  and at least two side parts  70 ,  71  between the sole part and the instep part. As shown in  FIG. 13 , sole part  69 , instep part  72  and side parts  70 ,  71  are embodied to be situated respectively under, above and to the side of the foot (v) of the leg in a situation of use. In determined embodiments at least one of the sole part and the instep part is manufactured from elastic material so that the stocking can be slid over the foot and already remains clampingly on the foot to a certain degree. In order to bring about the correct (higher) degree of compression on the foot the pressure in pressure compartment parts  73 ,  74  can be increased as desired by supplying air via valve mechanism  4 . This is because pressure compartment  63  of stocking  60  extends in at least one of the side parts (preferably in both side parts  70 ,  71 ) and each of the pressure compartment parts  73 ,  74  inside second stocking element  62  is in (open) connection with the pressure compartment part  75  inside first stocking element  61 . 
     First stocking element  61  is constructed from at least an inner wall  70  and an outer wall  71 . More generally, both walls  70 ,  71  are manufactured from flexible and pliable material so that stocking element  61  can be wrapped easily round a leg of a random user. The walls  70 ,  71  of first stocking element  61  and the walls of the side parts of second stocking element  62  preferably further take an airtight form and are attached (for instance sealed) to each other along the edges such that the pressure compartment  63  is formed between the two walls  70 ,  71 . 
     The material of the walls  70 ,  71  of first stocking element  61  and that of side parts  70 ,  71  of the second stocking element are preferably manufactured from plastic, such as thermoplastic polyurethane (TPU) or polypropylene. The outer walls preferably have a wall thickness of between 100 and 300 μm and the inner walls a wall thickness of between 50 and 100 μm. 
     When the user wishes to put on a stocking  60 , he or she places a foot in the second stocking element  62  and ensures that second stocking element  62  is held tightly around the foot as a result of the elastic material properties of instep part  72  (and/or sole part  69 ). The user then closes the first, opened stocking element  61  from the opened position shown in  FIG. 11  and fastens the longitudinal edges of first stocking element  61  to each other by means of suitable fastening means. In the shown embodiment the fastening means comprise a first strip of hook and loop element  66  (provided on a first longitudinal outer end of stocking element  61 ) and a second strip of hook and loop element  67  (provided on a second, opposite longitudinal outer end of stocking element  61 ). When the two strips are pressed together, first stocking element  61  can be attached to the leg, essentially independently of the shape and dimensions of the calf. A suitable medium (for instance a gas such as air) can then be supplied via valve mechanism  4  so that the pressure compartment in first and second stocking element  61 ,  62  expands and thereby allows the stocking to exert the desired, adjustable compression force on both the calf and the foot. 
     Although not shown in the figures, in the embodiment of  FIGS. 11-13  the material can also be provided with one or more stretch-limiting elements, for instance stretch-limiting means of the above described type. 
     The invention is not limited to the embodiment thereof described herein. The rights are defined by the following claims, within the scope of which many modifications can be envisaged.