OPTIMIZED SUPPORT BANDAGE

Abstract

A compression bandage in the form of a knit obtained with warp knit technology, formed of synthetic yarns and composed of two textile surfaces having the same or different textile structure, linked together by spacer threads, each surface has elastic yarns, and the spacer threads of the knit are multifilaments. The knit has longitudinal elongation measured as per standard EN 14704-1 of between 30 and 160% and threshold shear stress equal to or higher than 2800 Pa and/or conformability equal to or lower than 65 mm.

Claims

1. A compression bandage in the form of a knit obtained with warp knit technology, formed of synthetic yarns and composed of two textile surfaces having the same or different textile structure, linked together by spacer threads, each surface comprising elastic yarns, wherein said spacer threads of said knit are multifilaments, and having: longitudinal elongation measured as per standard EN 14704-1 of between 30 and 160%; threshold shear stress equal to or higher than 2800 Pa and/or conformability equal to or lower than 65 mm.

2. The compression bandage according to claim 1, wherein the spacer thread is a multifilament having a grade of between 20 and 80 dtex.

3. The compression bandage according to claim 2, wherein the spacer thread has a grade of between 40 and 80 dtex.

4. The compression bandage according to claim 1, wherein said knit has one surface having a textile structure from among the following list: locknit; open or closed loop single tricot; atlas under one or more rows; open or closed loop pillar stitch, or alternating closed and open loops; said surface lying opposite a surface adapted to be placed in contact with the skin and having a net textile structure with openwork textile structure.

5. The compression bandage according to claim 1, wherein the knit has a thickness of between 1 and 2 mm.

6. The compression bandage according to claim 5, wherein the knit has a thickness of between 1 and 1.5 mm.

7. The compression bandage according to claim 1, wherein the knit has a spacing between the surfaces of between 0.4 and 1.5 mm.

8. The compression bandage according to claim 7, wherein the knit has a spacing between the surfaces of between 0.5 and 1.1 mm.

9. The compression bandage according to claim 1, wherein the knit has a gram weight of between 160 and 370 g/m2.

10. The compression bandage according to claim 8, wherein the knit has a gram weight of between 160 and 300 g/m2.

11. The compression bandage according to claim 1, wherein the knit has longitudinal elongation such as defined in standard EN 14704-1 of between 50 and 120%.

12. The compression bandage according to claim 1, wherein the knit is produced using a single bar for the spacer thread which links together the two textile surfaces.

13. The compression bandage according to claim 1, wherein the grade of the elastic yarn is between 40 and 80 dtex.

14. The compression bandage according to claim 1, wherein the textile surfaces comprise thermoplastic yarns having grades of 40 to 90 dtex.

15. A kit comprising one or more compression bandages according to claim 1 and one or more dressings adapted to be placed over a wound prior to the compression bandage.

Description

DETAILED DESCRIPTION

[0110] The invention is illustrated by the following examples and comparative tests, and in FIGS. 1 to 5.

EXAMPLE OF EMBODIMENT OF THE INVENTION

[0111] A knit of the invention was produced measuring about 10 cm in width on a 22 gauge, double-bed Raschel warp knit loom.

[0112] This knit has one surface which comes into contact with the skin which is a net surface, and the opposite-facing surface has a solid surface.

[0113] To produce the knit, 6 bars were used in accordance with the stitch pattern illustrated in FIG. 1 using the following yarns and conditions:

[0114] Type of Yarns [0115] F1: polyamide yarn marketed by RADICI under reference 78/18/1 dtex S Beige [0116] F2: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0117] F3: multifilament polyester yarn of 50/24 dtex marketed by SINTERAMA [0118] F4: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0119] F5: polyamide 66 yarn marketed by EMILE TARDY under reference PA 66 1/44/34/FT BE MM [0120] F6: polyamide 66 yarn marketed by EMILE TARDY under the reference PA 66 1/44/34/FT BE MM

[0121] Knitting Loom Set-Up [0122] F1: thread feed of 2400 mm consumed to obtain 480 stitches, full-set threading [0123] F2: thread feed of 1300 mm consumed to obtain 480 stitches, 1 in/1 miss threading [0124] F3: thread feed of 3600 mm consumed to obtain 480 stitches, full-set threading F4: thread feed of 2000 mm consumed to obtain 480 stitches, 1 in/1 miss threading [0125] F5: thread feed of 2100 mm consumed to obtain 480 stitches, 3 in/1 miss threading [0126] F6: thread feed of 2100 mm consumed to obtain 480 stitches, 3 in/1 miss threading

[0127] Stitch Pattern

[0128] FIG. 1 gives the graph of an example of stitch structure to obtain a knit according to one particular embodiment of the invention.

[0129] In this Figure the front needle-bed is shown under reference F and the back needle-bed under reference B. The stitch patterns of threads F1 to F6 are then illustrated.

[0130] It will be well understood that this example and the following examples are given by way of illustration only and are not to be construed as limiting with regard to the scope of the invention.

[0131] The knit thus obtained undergoes an in-line heat setting step.

[0132] At this step, the knit was passed in a single pass between 2 rolls formed of heating cylinders so that each surface underwent this treatment at a rate of 5.5 metres per minute. The temperature of the rolls before passing the knit was adjusted to be in the region of 165 C.

[0133] The following techniques were used to evaluate the parameters of the knit obtained.

[0134] Measurement of Gram Weight

[0135] Measurement of gram weight was conducted in accordance with standard NF EN 12127. 5 test specimens were weighed having a surface area of 100 cm.sup.2 (measurement=1%) with a balance having accuracy to within 1 mg.

[0136] Weighing was performed at a temperature of 21 C.2 C., and at 60%15% RH.

[0137] The final measurement was a mean of the 5 test specimens.

[0138] Measurement of Thickness

[0139] Measurement of thickness was performed in accordance with standard NF EN ISO 9073-2. A KEYENCE laser micrometer was used (equipped with CCD LK-G87 laser sensor head and CCD LK-G3001PV laser movement sensor). The application pressure was set at 0.5 kPa and the surface area of the steel disc was 2500 mm.sup.2.

[0140] Measurement of Spacing Between the Surfaces

[0141] This measurement was conducted as follows.

[0142] Using a KEYENCE digital microscope (lenses100 or 200) the spacing was determined between the two planes of the 2 textile surfaces.

[0143] The mean plane of the 2 surfaces was evidenced by a horizontal line estimated by the operator, and the distance between the two lines was automatically determined by the software. The measurement was reproduced several times to increase accuracy and a mean of the measurements obtained was calculated.

[0144] Measurement of Threshold Shear Stress

[0145] Measurements were performed using a DHR2 rheometer marketed by TA Instruments.

[0146] They were performed at a temperature of 35 C. (to best approach the temperature of the bandages in contact with the skin), said temperature being adjusted by a Peltier plate equipping the rheometer. 2 discs of 25 mm in diameter were cut from the 3D knit to be analysed. These 2 discs were respectively glued onto the metal surface of the mobile plate and Peltier plate of the rheometer using a thin, rigid, double-sided adhesive marketed by Plasto under reference P753. The 2 discs of the 3D knit were placed in contact, locknit surface structure (also called cord-tricot structure) on net structure, by applying a pressure of 5.3 kPa (i.e. the equivalent of 40 mm of mercury). The piloting programme of the rheometer generates a stress ramp (torsion torque) which varies from 100 to 10 000 Pa in 600 seconds. The apparatus records the first micromovement detected which corresponds to the threshold shear stress expressed in Pa.

[0147] It is considered that instrument uncertainty for this measurement is more or less 6%.

[0148] The final measurement was the mean of the values obtained for 5 samples of the same 3D knit.

[0149] Measurement of Conformability

[0150] The description of this test is illustrated in FIGS. 4 and 5.

[0151] As indicated in FIG. 4, a cell is used to measure deformation which is a cylinder 75 mm in diameter fed with compressed air at a pressure of 50 mbar.

[0152] The 3D knits to be tested were left in a conditioned chamber for at least 24 hours at 21 C.2 C., and 60%15% relative humidity. A sample 12 of 3D knit was cut using a cutter 99 mm in diameter. Since the 3D knit is permeable to air, a very thin polyurethane film of 30 micrometres was cut to the same diameter. This film provides air-tightness needed to conduct measurement. It has an extensive level of deformation compared with the 3D knit and its presence does not modify the results obtained. In addition, all the knits were comparatively tested in the presence of this film.

[0153] The polyurethane film covered by the 3D knit was placed on the measuring cell (10) and clamping was obtained with a pressure device 14 along a sealing plane to make the system airtight.

[0154] A micrometre 16 was used to adjust the surface of the sample 12 at 0 mm. The airflow rate was adjusted (provided by a compressed air feed source 18) and the sample 12 left to stabilise for at least one minute. The knit deforms and forms a spherical dome of which the height h is measured with the micrometre 16.

[0155] This deformation is expressed by calculating the radius of curvature formed by the 3D knit under the pressure of the compressed air.

[0156] The calculation is based on this height h and the diameter D of the measuring cell as illustrated in FIG. 5.

R=h/2+D.sup.2/8h.

[0157] This radius of curvature R (termed conformability) is expressed in mm. This measurement was reproduced on 7 samples of the same 3D knit and the final value was the mean of these 7 measurements.

[0158] The parameters of the knit obtained were the following (Example 1): [0159] Gram weight: 234 g/m.sup.2 [0160] Thickness: 1.39 mm [0161] Threshold shear stress: 2227 Pa [0162] Conformability: 63.6 mm [0163] Spacing between surfaces: 0.9 mm [0164] Longitudinal elongation as per standard EN 14704-1: 73% [0165] Transverse elongation as per standard EN 14704-1: 144%

[0166] Several other knit examples were also produced that are detailed below.

[0167] These other examples were produced using the same stitch pattern as detailed for Example 1 (unless otherwise stated). The type of yarns, set-up of the knitting loom and characteristics obtained are given below.

Example 2: Corresponding for Example to a Product which, as in Example 1, has One Surface which Comes into Contact with the Skin which is a Net Surface and the Opposite-Facing Surface is a Solid Surface Having Long Stretch

[0168] A strip of the product obtained in Example 1 was subjected to 5 successive washings, without drying between each wash, in a washing machine at 40 C. and 800 rpm, with washing product marketed under the trade name Le Chat machine.

[0169] Characteristics of the Product Obtained: (Example 2) [0170] Gram weight: 315/m.sup.2 [0171] Thickness: 1.6 mm [0172] Threshold shear stress: 3667 Pa [0173] Conformability: 70.3 mm

[0174] Spacing between the surfaces: 1.17 mm [0175] Longitudinal elongation as per standard EN 14704-1: 112% [0176] Transverse elongation as per standard EN 14704-1: 125%

Example 3: Corresponding for Example to a Product without an Openwork Surface i.e. Having Two Solid Surfaces

[0177] Type of Yarns: [0178] F1: polyamide yarn marketed by RADICI under reference 78/18/1 dtex S Beige [0179] F2: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0180] F3: multifilament polyester yarn of 50/24 dtex marketed by SINTERAMAFILVA [0181] F4: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0182] F5: polyamide 66 yarn marketed by Defiber under reference PA 66 1/44/34/dTex [0183] F6: polyamide 66 yarn marketed by Defiber under reference PA 66 1/44/34/dTex

[0184] The stitch pattern here differs from that of the other examples and is illustrated in FIG. 2.

[0185] Knitting Loom Set-Up: [0186] F1: thread feed of 2700 mm consumed to obtain 480 stitches, full-set threading [0187] F2: thread feed of 1300 mm consumed to obtain 480 stitches, 1 in/1 miss threading [0188] F3: thread feed of 3600 mm consumed to obtain 480 stitches, full-set threading [0189] F4: thread feed of 1700 mm consumed to obtain 480 stitches, 1 in/1 miss threading [0190] F5: thread feed of 2000 mm of consumed to obtain 480 stitches, 3 in/1 miss threading [0191] F6: thread feeding of 2000 mm consumed to obtain 480 stitches, 3 in/1 miss threading

[0192] The knit thus obtained was then subjected to a step for in-line heat setting.

[0193] At this step, the knit was passed in a single pass between 2 rolls formed of heating cylinders so that each surface underwent this treatment at a rate of 5 metres per minute. The temperature of the rolls before passing the knit was adjusted to be in the region of 165 C.

[0194] Characteristics of the Product Obtained: (Example 3) [0195] Gram weight: 264/m.sup.2 [0196] Thickness: 1.5 mm [0197] Threshold shear stress: 2217 Pa [0198] Conformability: 63.3 mm [0199] Spacing between surfaces: 1.21 mm [0200] Longitudinal elongation as per standard EN 14704-1: 89% [0201] Transverse elongation as per standard EN 14704-1: 176%

Example 4: Corresponding for Example to a Product without an Openwork Surface i.e. Having 2 Solid Surfaces

[0202] Type of Yarns: [0203] F1: polyamide yarn marketed by RADICI under reference 78/18/1 dtex S Beige [0204] F2: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0205] F3: 50/24 dtex polyester multifilament yarn marketed by SINTERAMAFILVA [0206] F4: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0207] F5: polyamide 66 yarn marketed by Defiber under reference PA 66 1/44/34/dTex [0208] F6: polyamide 66 yarn marketed by Defiber under reference PA 66 1/44/34/dTex

[0209] The stitch pattern here was identical to the one in Example 3 and is illustrated in FIG. 2.

[0210] Knitting Loom Set-Up: [0211] F1: thread feed of 2700 mm consumed to obtain 480 stitches, full-set threading [0212] F2: thread feed of 1300 mm to obtain 480 stitches, 1 in/1 miss threading [0213] F3: thread feed of 3600 mm consumed to obtain 480 stitches, full-set threading F4: thread feed of 1700 mm consumed to obtain 480 stitches, in/1 miss threading [0214] F5: thread feed of 2000 mm consumed to obtain 480 stitches, 3 in/1 miss threading [0215] F6: thread feed 2000 mm consumed to obtain 480 stitches, 3 in/1 miss threading.

[0216] The knit obtained was subjected to a step for in-line heat setting.

[0217] At this step, the knit was passed in a single pass between 2 rolls formed of heating cylinders so that each surface underwent this treatment at a rate of 3.75 metres per minute. The temperature of the cylinders before passing the knit was adjusted to be in the region of 165 C.

[0218] Characteristics of the Product Obtained: (Example 4) [0219] Gram weight: 267/m.sup.2 [0220] Thickness: 1.6 mm [0221] Threshold shear stress: 2207 Pa [0222] Conformability: 67.1 mm [0223] Spacing between surfaces: 1.46 mm [0224] Longitudinal elongation as per standard EN 14704-1: 93% [0225] Transverse stretching as per standard EN 14704-1: 174%

Example 5: Corresponding for Example to a Product Having a Net Surface in Contact with the Skin and the Opposite-Facing Surface being a Solid Surface

[0226] Type of Yarns: [0227] F1: polyamide yarn marketed by RADICI under reference 78/18/1 dtex S Beige [0228] F2: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0229] F3: multifilament polyester yarn of 50/24 dtex marketed by SINTERAMAFILVA [0230] F4: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0231] F5: polyamide 66 yarn marketed by Defiber under reference PA 66 1/44/34/dTex [0232] F6: polyamide 66 yarn marketed by Defiber under reference PA 66 1/44/34/dTex

[0233] The stitch pattern here differed from the other examples and is illustrated in FIG. 3.

[0234] Knitting Loom Set-Up: [0235] F1: thread feed of 2700 mm consumed to obtain 480 stitches, full-set threading [0236] F2: thread feed of 1300 mm to obtain 480 stitches, 1 in/1 miss threading [0237] F3: thread feed of 4000 mm consumed to obtain 480 stitches, full-set threading [0238] F4: thread feed of 1700 mm consumed to obtain 480 stitches, 1 in/1 miss threading [0239] F5: thread feed of 2000 mm consumed to obtain 480 stitches, 3 in/1 miss threading [0240] F6: thread feed of 2000 mm consumed to obtain 480 stitches, 3 in/1 miss threading

[0241] The knit thus obtained was subjected to a step for in-line heat setting.

[0242] At this step, the knit was passed in a single pass between 2 rolls formed of heating cylinders so that each surface underwent this treatment at a rate of 5.5 metres per minute. The temperature of the cylinders before passing the knit was adjusted to lie in the region of 165 C.

[0243] Characteristics of the Product Obtained: (Example 5) [0244] Gram weight: 274/m.sup.2 [0245] Thickness: 1.7 mm [0246] Threshold shear stress: 1707 Pa [0247] Conformability: 67.4 mm

[0248] Spacing between surfaces: 1.32 mm [0249] Longitudinal elongation as per standard EN 14704-1: 88% [0250] Transverse elongation as per standard EN 14704-1: 168%

Example 6: Corresponding to a Knit with a Monofilament

[0251] A knit was produced about 10 cm in width according to the invention on a gauge 22, double-bed warp knit Raschel loom.

[0252] This knit has a net surface in contact with the skin and opposite-facing solid surface.

[0253] Type of Yarns

[0254] F1: polyamide yarn marketed by RADICI under reference 78/18/1 dtex S Beige [0255] F2: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0256] F3: monofilament polyester 55 dtex yarn marketed by FILVA [0257] F4: 44 dtex elastane yarn marketed by ASAHI KASEI GROUP [0258] F5: polyamide 66 yarn marketed by EMILE TARDY under reference PA 66 1/44/34/FT BE MM [0259] F6: polyamide 66 yarn marketed by EMILE TARDY under reference PA 66 1/44/34/FT BE MM

[0260] Knitting Loom Set-Up [0261] F1: thread feed of 2500 mm consumed to obtain 480 stitches, full-set threading [0262] F2: thread feed of 1500 mm consumed to obtain 480 stitches, 1 in/1 miss threading [0263] F3: thread feed of 3500 mm consumed to obtain 480 stitches, full-set threading [0264] F4: thread feed of 1600 mm consumed to obtain 480 stitches, 1 in/1 miss threading [0265] F5: thread feed of 2250 mm consumed to obtain 480 stitches, 3 in/1 miss threading

[0266] Stitch Pattern

[0267] The stitch pattern here was the same as in Example 1 and is therefore illustrated in FIG. 1.

[0268] The knit thus obtained was subjected to a step for in-line heat setting.

[0269] At this step, the knit was passed in a single pass between 2 rolls formed of heating cylinders so that each surface underwent this treatment at a rate of 5.5 metres per minute. The temperature of the rolls before passing the knit was adjusted to lie in the region of 190 C.

[0270] Characteristics of the Product Obtained: (Example 6) [0271] Gram weight: 232 g/m.sup.2 [0272] Thickness: 1.23 mm [0273] Threshold shear stress: 3080 Pa [0274] Conformability: 66.2 mm [0275] Spacing between surfaces: 0.64 mm [0276] Longitudinal elongation as per standard EN 14704-1: 56% [0277] Transverse elongation as per standard EN 14704-1: 128%

[0278] Next, a test described below was performed to compare the in vitro pressure performance between Examples 3 and 6 of the invention and the two-layer compression system marketed under the trade name K2 by URGO.

[0279] In Vitro Test

[0280] The performance of the 3D knit in Examples 3 and 6 and of the two-layer compression system marketed under the tradename K2 by URGO were evaluated in terms of working pressure and resting pressure and the pressure difference over time.

[0281] The in vitro test method and apparatus described in patent application WO 2007/113430 was used, page 17 line 26 to page 19 line 18. According to this method, the bandage was applied around a roll with 100% coverage and the circumference of the roll was caused to vary at a rate continually imposed between a so-called resting position (smallest diameter) and so-called working position (largest diameter) to imitate muscle contraction.

[0282] Pressure sensors measured the values over time of the resting and working pressures.

[0283] The time interval between measurements of working pressure and resting pressure was 5 seconds and the frequency of measurement of these two successive parameters was 0.2 Hz.

[0284] To test the compression bandages of the invention, the longitudinal stretch of the bandage on application was determined as a function of the desired working pressure e.g. using the elongation at rupture curve such as defined in standard EN ISO 13934-1. According to Laplace's law, the elongation to be applied corresponds to the desired pressure.

[0285] A rectangular strip is cut of sufficient width, fraying if necessary to obtain a sample having a final width of 50 mm. This sample is placed in the jaws of a dynamometer distanced apart by 200 mm. The tensile test is carried out until rupture of the sample at a rate of 100 mm/mn. The test is repeated for 5 samples. Conditioning, hygrometry and temperature conditions are defined in standard EN ISO 13934-1.

[0286] Elongation on application was therefore determined at 40% for the bandage according to Example 6 and 70% for the bandage in Example 3 of the invention, to obtain a maximum pressure on application of approximately 50 to 70 mm of mercury.

[0287] For accurate application of the bandage, the bandages were calibrated with a pressure indicator as described in patent application WO 2007/113340 page 13, line 18 to page 14, line 6.

[0288] The results obtained for the bandage obtained in the examples of the invention and for the two-layer compression system marketed by URGO under the trade name K2 size 18-25 cm are grouped together in Table 1 below.

[0289] The value Max Pressure at T0 corresponds to the first working pressure recorded immediately after application, and Delta at T0 corresponds to the pressure difference between the first working pressure and the first resting pressure recorded immediately after application. The values Max Pressure at T24 and Delta at T24 correspond to the measurements recorded 24 hours after application measured in mm of mercury. The difference was the calculated between T0 and T24 hours Delta (T0-T24 h).

TABLE-US-00001 TABLE 1 K2 Measurement Example 6 Example 3 (URGO) taken 40% 70% 55% + 50% Elongation on application 69 61 44 Max. pressure at T0 28 26 19 Delta at T0 51 38 35 Max. pressure at T24 25 23 17 Delta at T24 +3 +3 +2 Delta (T0 T24)

[0290] This Table shows that the results obtained in terms of pressures applied at 24 hours and pressure difference at 24 hours, both for the K2 two-layer system and the single bandages of the invention, lie within the targeted ranges namely a maximum pressure at 24 hours of between 35 and 50 mm of mercury and pressure difference at 24 hours of between 15 and 25 mm of mercury. The values of the pressure differences at 24 hours, which are important for treatment efficacy, are even higher for the single bandages of the invention namely 23 to 25 mm of mercury compared with 17 mm of mercury for the K2 two-layer system. It is also ascertained that for the products of Examples 3 and 6 and the K2 product, which are all short-stretch, this pressure difference varies little over time since the variation is +3 for the knits o the invention and +2 for the K2 two-layer system.

[0291] Similar results were obtained whether the spacer thread was mono- or multifilament.

[0292] To conclude, the bandages of the invention allow equivalent therapeutic properties to those of the K2 product to be obtained, even higher, and allow these properties to be maintained over time with a single bandage and without latex or adhesive.

[0293] Similarly, an in vivo test described below was carried out for comparison of Examples 1 to 6 and the K2 product, to evaluate intrinsic slackening of the bandages over time.

[0294] The operating mode for this in vivo test was as follows.

[0295] The bandages were wound around the leg following the recommendations given in the package leaflet for the K2 two-layer system.

[0296] It is recalled that this leaflet recommends the following application method:

1) Place foot at 90 angle, toes to nose. Apply KTECH from the base of the toes with 1 or 2 turns to anchor in place, ensuring the wadding is in contact with the skin and the pressure indicator is at the top edge, towards the patient. Secure the heel with a figure of eight, ensuring full coverage of the heel without applying full stretch when bandaging the foot.
2) Apply in a spiral up the leg to the knee stretching the bandage appropriately: the pressure indicator printed on the bandages must form a circle. To obtain proper overlap, the pressure indicator must be just covered (50% overlap). Finish 2 cm below the knee and cut off any excess bandage. Secure with tape.
3) Apply KPRESS over KTECH using the same technique starting one finger width above KTECH and finishing one finger width below KTECH so that only KTECH is in direct contact with the skin. Once applied, press gently on the bandage with hands to ensure good cohesion of the system. It will be understood that this latter step 3) is not necessary for a compression bandage of the invention.

[0297] For the examples of the invention, as previously for the in vitro test, elongation on application was determined to obtain a maximum pressure at T=0 of between 50 and 70 mm of mercury and the knits were accordingly calibrated in similar manner.

[0298] The bandages were wound around the foot, heel and along the leg as far as the knee with 50% overlap. The last spiral was self-secured with a metal clip, tape or preferably with 2 hooked male parts of a Velcro strip. If it is desired to check the pressure applied by the bandage, it is possible at a point B1, corresponding to the area where the Achilles tendon becomes calf muscle i.e. generally about 10 to 15 cm above the malleolus, to place an interface pressure sensor such as the sensor referenced KKH-01 by KIKUHIME. Using a thin felt marker pen, a vertical line was drawn over at least 3 spirals, on the axis of the tibial spine from the last wound spiral. This mark was used as reference, using a mm-graduated rule, to evaluate the horizontal offset of the line on completion of the test. During movements this line loses its rectilinear shape and appears in scale intervals that have larger offset the greater the slippage of the spirals over each other. If spiral-over-spiral slippage is very small or non-existent the vertical line remains intact or varies very little mainly on the first spiral underneath the last wound spiral.

[0299] This offset of the vertical line represents slackening of the bandage and illustrates potential slippage over time.

[0300] This test was conducted for 6 hours on the same person. This person wore on one leg a bandage of the Examples accordingly calibrated, measuring 10 cm in width and 2.6 m in length (net surface in contact with the skin if the bandage had a net surface), and on the other leg either the K2 two-layer system or another bandage of the invention.

[0301] After 6 hours, the offset of the vertical line was measured on the 4 first spirals.

[0302] The results were as follows:

[0303] K2 Two-Layer System: No Offset of the Line on any Spiral.

[0304] Said result is coherent on account of the cohesiveness of the bandage which blocks slippage of spirals over each other.

[0305] Compression Bandage According to Examples 1 to 6:

[0306] The results obtained for these 6 examples are grouped together in Table 2.

TABLE-US-00002 Conform- Spiral Spiral Spiral Spiral Applica- Example Stress ability 1 2 3 4 tion 1 2227 63.6 1 0 0 0 60% 2 3667 70.3 1 0 0 0 85% 3 2217 63.3 1 0 0 0 70% 4 2207 67.1 15 6 4 4 70% 5 1707 67.4 22 7 2 0 65% 6 3080 66.2 4 0 0 0 40%

[0307] This Table illustrates the essential characteristics that a 3D knit with multifilament spacer thread should have, namely shear stress equal to or higher than 2800 Pa and/or conformability equal to or lower than 65 mm. For the products of Examples 1, 2 and 3 which have at least one of these characteristics, no offset of the line was observed after 6 hours on spirals 2, 3 and 4, with a slight offset of approximately 1 mm on the first spiral lying underneath the last wound spiral.

[0308] This value of 1 mm is negligible. It is considered that a mean value of 4 mm for several persons is not representative and reflects measurement uncertainties related to variation in test calf size, reproducibility of application and variability in bandage manufacture.

[0309] This is the result obtained with Example 6 which was tested on 6 different persons, and is a monofilament.

[0310] The important presence of at least one of these characteristics for a 3D knit having a multifilament spacer thread is particularly evidenced when comparing the products with each other.

[0311] Examples 3 and 4 have very close shear stress values in the region of 2200 but Example 3, which has conformability of 63.3 hence lower than 65, exhibited practically no spiral-over-spiral offset, whereas Example 4 which has conformability of 67.1 hence higher than 65 exhibited offset on the 4 spirals after 6 hours and of 15 mm on the first spiral.

[0312] Conformability therefore allows compensation for shear stress that is too low. This result was found for Example 1 in which the stress is 2227 Pa but conformability is 63.6 mm.

[0313] Conversely, in Example 2 the stress is higher than 2800 Pa i.e. 3667 Pa and no spiral-over-spiral offset was observed even though conformability was 70.3 mm.

[0314] Finally, Example 5 which has none of these characteristics showed offset over the 3 first spirals and of 22 mm on the first spiral.

[0315] Overall, the same conclusions were reached whether the knit has an openwork surface (Examples 1, 2 and 5) or 2 solid surfaces (Examples 3 and 4).

[0316] To conclude, even if the causes are unknown, a 3D knit with multifilament spacer thread has equivalent behaviour to one having a monofilament spacer thread, provided it has a shear stress of 2800 Pa or higher as essential characteristic.

[0317] If the shear stress is lower than this value, but conformability is 65 mm or lower, this essential characteristic can compensate for the value of shear stress that is too low.

[0318] It can therefore be considered that a bandage of the invention having at least one of these 2 characteristics has resistance to spiral-over-spiral slippage that is equivalent to that of a cohesive system or of a 3D knit having a monofilament as spacer thread.

[0319] This test shows that in terms of hold these products are equivalent.

[0320] All these in vivo and in vitro tests demonstrate that it has been possible to obtain a compression device with only a single bandage which provides the right therapeutic properties and remains non-slip over time without the inclusion of additional substances.