Abstract
Background
Compression is a common therapy for management of chronic disease, including oedema of the lower limb. Modern compression interventions exert pressure on the lower limb through use of one or more materials which exert pressure against the limb over time. Where these materials are textiles, they range from elastic to inelastic, and are produced using knitting, weaving, or other textile technologies which can be manipulated to control performance properties. Thus, understanding of both the materials/textiles and the human body is needed if the most appropriate compression device and treatment strategy is to be used. Neither is independent of the other. This review aims to enhance understanding of critical textile performance properties and how selection of textiles may affect treatment efficacy when managing chronic oedema of the lower limb.
Method
Relevant papers for review were identified via PubMed Central® library, and Google Scholar using keywords associated with textile-based treatments of the oedematous lower limb and wider interdisciplinary factors.
Results
Assessment of the disorder, the severity of oedema, and location of fluid accumulation are required to inform treatment of chronic oedema. While the need to understand the patient is well established (e.g. age, sex, body mass index, skin thickness and colour, patient compliance with treatment), information about preferred compression systems and material structures, and inherent properties of these, is generally lacking.
Conclusion
Greater detail about materials used (e.g. fabric structure, number and order of layers, fibre content) and patient diagnosis (e.g. underlying cause, severity, location of oedema; patient age and sex; evidence of compliance with treatment; pressure exerted; lower leg shape, size, and properties of the tissue) is needed to facilitate advances in efficacy of compression treatment. Reduced limb swelling with a textile-based treatment occurs simultaneously with changes to the textile itself. Textiles cannot be considered inert.
Textiles for compression interventions are used in a range of applications such as in sport recovery, to enhance proprioception, and in the management of oedema.1,2 Chronic oedema, noticeable swelling resulting from abnormal accumulation of fluid in the interstitial spaces of the body, is associated with venous disorders, inflammation, and/or trauma.3,4 Earliest published information on rates of oedema (Table 1) date to the early 2000s and suggest a rate of 135 per 1000, 5 with rate increasing with age and being more than twice as common among females as males.3,6 More recent data on prevalence were not identified at the time of this review. A challenging clinical problem, oedema is characterised by slowness of recovery and a tendency to transform to other types of severe venous disease i.e. skin pigmentation, venous eczema, ulcer.4,7–9 Over time and/or in the case of inadequate treatment, the risk of progression in severity increases.10–12 Potential for pigmentation, venous eczema, and ulcer formation and treatment of these are, however, beyond the scope of this current review.
Prevalence of chronic venous oedema.
Search strategy
Interdisciplinary factors affecting textile-based treatments of the oedematous lower leg were identified from the refereed, published literature. Sources examined included PubMed Central® (PMC) library, Google Scholar, patents (United States of America, Australia, Europe (covering Germany, France, Netherlands, Belgium, Luxembourg, Italy, Turkey, Greece, Cyprus, Malta, San Marino, Lithuania, Latvia, Monaco 1 ), medical and textile-based journals (400 + papers), and websites for compression products. Synonymous keywords (i.e. oedema in lower limb or lower leg or lower extremities; compression textile or therapy or wrap or mode or modalities; interdisciplinary factors or parameters (physiological, human anthropometric, textile); Laplace law; Pascal law; compression stocking or bandage or pneumatic compression device or Velcro® compression; efficacy, effectiveness; patient compliance) were used to ensure all relevant references were included. Language was restricted to the international language of science, English.
Background
The well recognised compression therapy treatment relies on bandages and garments/devices made from fibres, yarns, and fabrics as a means of managing the many different types of chronic oedema.1,2 In the case of garments, these must be able to transform to body contours (as occurs in circular knit structures such as stockings); control volume; and be manufactured to accommodate different body shapes through differently-sized products. If these characteristics are not present, then products need to be applied to the body by practitioners/trained caregivers who control the interaction between the textile and the body. This management of differences in size/volume is critical if the pressure exerted is to be appropriate for the specific body site. Pressure exerted must vary depending on body site, treatment, and individual patient. Management of this is aided through classification systems such as those listed in Table 2. 2 13–16 Professional guidelines for selection of compression devices for lower extremities, not limited to oedema, are presented by Bjork et al. 17
Classification system for compression stockings based on pressure range.
Compression textiles/products used in treatment are also commonly constructed from multiple layers. Choices relating to selection include, but are not limited to the order in the system a textile layer is positioned, patient tolerance of the treatment/pressure, and how long the compression product is in use (critical given the decay curve typical of textile extension over time 24 ).
In resting supine positions, textile compression products apply on-going pressure against the patient's skin surface. In resting upright positions, as the venous pressure is increased, greater external pressure is needed than that in the resting supine position if the same effect is to be achieved. When 'working' (e.g. walking), the underlying muscles contract and expand exerting pressure against the compression fabric and pressure in the veins of the limb is increased. This increased pressure stimulates pumping of the lymphatic system and encourages re-absorption of lymphatic fluid, thus oedema is reduced.25–27 Simultaneously, performance of the textiles forming part of the compression treatment also changes due to their viscoelastic properties, 18 and moisture/thermal properties. It is understanding of these changes, and interactions between the patient and the textile, that will enable treatment to be fine-tuned. For example, in relation to the lower limb, elastic, semi-elastic, non-elastic; knitted or woven structures28,29 may be used. Regardless of whether these are chosen and assembled in situ or are purchased as multiple-layer composites, understanding the properties of single- and multiple-layer configurations is essential if treatment is to be enhanced.
In compression intervention, a wide variety of treatment pressures are used with accuracy of application largely affected by practitioner skill and experience.30,31 Different bandaging techniques (spiral, putter, and figure-of-eight) used in varying static postures (resting, sitting, or standing) with different bandages (elastic or inelastic) result in different compression.30,32 In multi-layer bandaging, the order in which the bandages are wrapped on the leg (elastic layer over inelastic layer or vice versa) also affects the interface pressure. 33 Examination of the effect of interactions among bandaging techniques, materials, and dynamic posture i.e. walking over time has not been identified. 32
A manikin study has focused on the dynamic condition of the lower leg, movement and bending of ankle and knee positions, showing that the dropped amount of bandage-manikin interface pressure over time is higher than that which occurs in the static condition. 34 This drop in interface pressure under dynamic conditions was increased by enhancing the displacement amplitude of the manikin, and tension level in the compression fabric. 34 However, changes in the radius of curvature of the leg while performing activities i.e. walking, running, or jogging, and bandaging techniques were not considered in this study.
Studies examining effectiveness of compression products used to manage oedema both clinically and in the home are summarised in Table 3. The diversity of products used, methods of evaluation/treatment, and outcomes of the different treatment decisions are summarised in this table.35–42 However, examination of effects of treatment choices in combination with known properties and performance characteristics of the compression products, has received less attention.43–47 The tendency to focus on the oedema, pressure required to treat, and the patient, while treating the textile properties as an unchanging constant fails to account for both the viscoelastic nature of textiles, and a wider range of interactions that occur among patient, pressure, and textile variables.
Efficacy of compression devices in managing oedema.
Note: Applied level of pressure decreases immediately after the application of inelastic compression bandages on the oedematous lower leg due to the oedema reduction. The change in pressure over a short period of time (i.e. 0–15 minutes) following application of a compression product, the time in which a rapid drop in pressure was reported by Ruznan et al., 18 was not reported in any of these studies. In the study of Mosti et al.,36–38 the pressure was measured after starting the compression treatment; the probe was then disconnected from the pressure measuring device and left in place under the compression systems; and finally, the probe was re-connected and pressure again measured before the compression devices were removed.
aPatients were diagnosed with oedema confounded with ulcer. Result pertaining to oedema only is given here.
bPatients were diagnosed with oedema confounded with ulcer. Result reported here pertains to oedema only.
Rapid developments in the textile processing sector and implications of this with regard to manufacture of distinctly different products has increased potential for improving design, production and performance of compression products. Textile structure developments (i.e. fibre, yarn, fabric, fabrication technologies) related to compression bandages were reviewed by Milosavljevic and Skundric in 2007, 48 and Liu et al in 2016. 29 In 2016, effects of physical-mechanical properties such as stiffness, elasticity, elastic hysteresis of textile structures on pressure performance; 29 and effects of both Laplace and Pascal laws were related to static and dynamic mechanisms of compression therapy.1,29 However, these reviews do not integrate the materials/textiles and the human body. Given neither is independent of the other, the current review seeks to examine existing textile-based compression interventions by exploring how the materials used in fabricating these compression devices, and human-based factors (such as anthropometry, body size and shape) affect the pressure generated by devices/products. Knowledge of chronic oedema (including severity and location on the body), and patient (such as age, sex, body mass index, skin thickness and colour; and patient compliance with pressure treatment) affect treatment outcomes, and these factors also influence selection of compression bandages/compression device.
Considerations affecting use of compression therapy
Physiological considerations
A critical variable affecting oedema, and performance of bandages and other devices, is that of gravity. When a person rises from lying to standing positions, venous pressure increases and blood accumulates in the lower leg due to gravity. In healthy individuals, venous pressure subsequently drops as a person walks and the calf muscles propel blood flow from the legs.1,49 In clothing design, this expansion of dimension while walking is normally accommodated by extension (stretch) of the textiles, and/or slip over/along the body. Additionally, thermal and moisture (liquid and/or vapour) interactions with the compression textiles are critical parameters influencing wearer comfort over time. 47 Given the release of the water and water vapour from different parts of the lower leg differs with activity (i.e. resting, walking), duration, and among environmental conditions, 50 textile-based compression devices must accommodate transfer of a wide range of moisture levels facilitating transfer from the skin to the environment.
In venous-diseased people with impaired venous drainage excess fluid accumulates in the interstitial spaces, and the volume of the limbs expands. 1 Application of textiles to the oedema-induced lower limb exert pressure as muscles contract, affecting venous return. For compression to be effective, the compression textile must exert sufficient pressure to overcome this in the veins of the lower leg in a standing position, and this pressure needs to be sustained over time if the necessary benefits are to be delivered. The actual pressure applied in any particular case also depends on the individual patient's pressure tolerance.
Human anthropometric considerations affecting efficacy of treatment
According to Laplace’s law the radius of the curvature of the leg at key locations, such as the tibial crest and calf, will affect the interfacial pressure between a fabric layer and the underlying skin surface. Higher pressure is produced when the radius is smaller than when the radius and thus the circle/oval is larger.1,51 Given the radius of curvature at any cross-section of the lower extremities (i.e. calf (gastrocnemius), tibial crest (anterior edge of the tibia bone)) is irregular, and differs among individuals and populations,1,52 textile pressure devices must accommodate fit considerations. In any particular cross section of the leg, these irregular curves can be visualised as a series of overlapping ellipses drawn so the radius of curvature best fits the curve of the body at a particular site.1,51
The shape of the leg has important implications in relation to pressure and garment design/use. The pressure exerted is affected by the properties of the underlying tissue and relative proportions of these at any particular cross section (i.e. soft tissue of muscular parts, hard tissues of bony parts). 53 Thus, there is greater risk of pressure damage due to excessive pressure exerted during therapy at some locations than others. This has implications in relation to compressive textile/product design and treatment choices. For example 1 the irregular cross-sectional shape of the tibia may require a compression product to be modified, perhaps by addition of padding materials between the compression device and the body surface;54–56 2 the conical-shaped surface of the leg may necessitate selection of bandages with greater adhesion (adhere to skin) and cohesive (self-adhering) characteristics;57–59 and 3 cyclic changes to leg dimension resulting from postural changes affect the radius of curvature, interface and resultant venous pressure,30,32 and therefore need to be accounted for. Thus postural effects, product sizing requirements, and venous pressure dynamics, in combination with textile or product selections influence the effectiveness of the compression intervention.1,60,61
The non-linear dynamics of extension/relaxation deformations in fabric and garments/textile products must be considered concurrently with the varied dimensions along the limb under compression. The non-linear dynamics increase complexity of treatment in terms of the pressure applied over the entire garment/product surface (e.g. in a range of garments, the greatest pressure was observed when the direction of tension was 60° to the length of knit fabric from ankle to knee 62 ).
Textile considerations affecting efficacy of treatment
Bandages, stockings, and pneumatic devices are the three common classifications used to group compression products, with properties of these reflecting the different materials, designs, and fabrication processes used.29,63 Compression products can be further grouped by elasticity and number of layers in the finished product. For example, a bandage can be inelastic or elastic, and single-layer or multi-layer. 3 In both single-layer compression bandages and when multiple-layer combinations of textiles of varying elasticity are used, the resultant pressure applied will differ due to hysteresis effects. Performance of a multiple-layer bandage system comprised of combinations of elastic (and/or inelastic) layers will differ from that of the constituent single layers.69,70 Applying several layers of an elastic bandage material tends to create an inelastic bandage system as the friction between the surfaces of the bandage layers opposes the elastic expansion of the fibres/yarns. 69 Further, a bandage can be fabricated via weaving, knitting, or non-woven processes, or combinations of these. By altering the manufacturing process, yarn properties (i.e. yarn density, twist, draw ratio structures), fabric structural design, fabrics of quite different density and thickness may be produced leading to the capacity to apply different pressures, and thus perform differently during use.43,71–74 In graduated compression stockings for example, thinner (mean 0.35 mm) and lighter fabrics (mass per unit area, mean 85 g/m2) were shown to exert less pressure than thicker, heavier fabrics. 75
The viscoelastic nature of compression bandages means the interface pressure applied decays over time24,76 concurrently with a reduction of venous volume, and consequential decreased circumference of the lower limb decreasing pressure over time.77,78 Performance of a compression bandage over time (8 hours) has been shown to depend on the yarn type and fabric structure with interface pressure reducing less in a fabric with greater yarn density. 76 Ruznan et al. 24 showed multiaxial stress-relaxation behaviour of a compression bandage over time (up to 120 hours) was a key parameter affecting performance, noting a rapid drop in pressure (i.e. ∼34% and ∼49% for crepe weave and plain weave fabric respectively with 50 mm circumference of ball; ∼37% and ∼43% for crepe weave and plain weave fabric respectively with 24.5 mm circumference of ball) within a short period of exposure (i.e. 0-15 minutes). Multiaxial stress-relaxation behaviour can provide useful information on when a bandage may need to be re-wrapped or replaced in order to maintain effectiveness of the treatment, thus demonstrating and emphasising the importance of appropriate textile selection.
Compression stockings and bandages may also be laundered for re-use as per the manufacturer’s instructions, with different washing and drying cycles known to be required for fabrics composed of different fibres and fabric structures.70,80 Replacement is needed when textile integrity is compromised. Advantages and disadvantages of various textile-based compression products have been reported by Nair, 81 and information on selected commercially available compression products (bandages, stockings) and their properties, described according to the “P-LA-C-E” (“Pressure level – LAyers – Components of material – Elasticity”) classification system addressed by the International Compression Club (ICC) in a consensus meeting, 69 is given in Table 4.
Commercial multi-component compression products – “P-LA-C-E” description.
aNote: single layer items may be elastic or inelastic; however, the elasticity of multiple layer systems comprised of combinations of elastic and/or inelastic layers may differ from that of the components.
Here the term elastic or inelastic is used for bandages with a single component, and the term “system” is used for bandage kits with multiple components.
Every bandage is applied on the lower limb with some overlap, which creates at least two-layers of bandage material at any specific location. Therefore, in such end applications, a single-layer bandage does not exist.
Evidence of effectiveness of compression textiles as an intervention for oedema
The effect of different types of compression modalities on chronic oedema has been compared,35–37 leading to the general conclusion that some compression is better than no compression. Yet a comprehensive review of the efficacy of compression textiles for chronic oedema suggests that while reviews of the efficacy of compression textiles (in treatment and recurrence of venous ulcers) have been conducted92–97 the lack of systematic experimental studies limits usefulness of the literature as a vehicle for improving efficacy.
Effects of highly extensible bandaging systems have been compared with intermittent pneumatic compression (IPC) systems.40,42 In Rowland, 40 pressure was applied using an IPC device twice a day only (one hour each in the morning and evening) and in bandage form the pressure was exerted all day with the bandage being applied by the community nurse three mornings a week and by the patient on the other days. While the IPC device initially resulted in a decrease in volume equal to the decrease in volume generated by the bandage device, this was not maintained. At the end of the trial, the reduction in oedema volume was greater in the group using the bandages than that using the IPC device. A possible explanation for the decline in IPC effectiveness over time 40 is that, between the twice daily applications fluid may have recharged the oedema volume. Further, the re-application of the bandages used by patients in the high stretch bandage group (by the community nurse three mornings each week) may have allowed the bandage to maintain the pressure more effectively over time compared to the IPC group where the pressure device was self-administered throughout the trial. 40 Thus, this paper is a further example of experimental design preventing effective comparison of compression treatments.
Comparison of another IPC device with a conventional, four-layer compression bandage/conventional therapy alone also found no statistical difference between groups. 42 The finding was again consistent with oedema volume reduction being higher in the pneumatic compression treated group (19%) than that in the conventional four-layer bandage group (11%). However, once again there was a lack of experimental detail. Description of dressing systems (dressing types, leg shape) and bandages used (width, thickness, practitioner’s skills) was not supplied, which in combination with a lack of information on experimental set up, hinders critical evaluation of the bandage and device performance. Of note is that all patients in the IPC group reported less pain. 42 Less pain is likely to be associated with better compliance, a critical issue given widely acknowledged concerns associated with patients failing to comply with treatment due to discomfort over time.
Mosti et al. 36 examined 40 legs (36 patients) and showed that adjustable Velcro® compression devices may be more effective in managing chronic oedema than inelastic bandaging perhaps. While an earlier report by Mosti et al. 37 indicated initial reduction in oedemateous leg volume was independent of the pressure applied (i.e. the reduction in volume was equal after one week irrespective of whether the compression therapy was given by short-stretch bandage (67 mm Hg) or light stocking (24.5 mm Hg)), findings do suggest ability to adjust fit (and thus pressure) was beneficial to patients.
Despite the number of published papers reporting investigation of compression products (Table 340–42), the best system to use with specific material, structures, and properties remains unclear. Most studies report use of commercial compression devices to determine the efficacy treatment. Often investigations have compared devices which were not alike or without sufficiently well-controlled study designs, and which provided limited description of parameters and/or inadequate details about the material components (i.e. material, mass per unit area, thickness). Further, applied level of pressure decreases immediately after the application of inelastic compression bandages on the oedematous lower leg due to the oedema reduction. The change in pressure over a short period of time (i.e. 0–15 minutes) following application of a compression product, the time in which rapid drop in pressure was recorded by Ruznan et al., 24 was not reported in any of these studies.
Treatment and patient compliance
Correct treatment of chronic oedema requires careful assessment and quantification of the disorder, the severity, and site of fluid accumulation. 98 Researchers have reported on the efficacy of a variety of different compression devices in managing chronic oedema.40,99–102 However, specific severity, consensus on treatment (duration, frequency of compression, level of pressure) is generally lacking. Understanding the patient (e.g. age, body mass index, sex, skin thickness, skin temperature, skin colour), whether the oedema condition improves, is present in one or both legs, should influence the selection of compression device, a critical step if an appropriate intervention is to result. Also critical, is monitoring both effects and efficacy (e.g. pain, depression, anxiety, skin colour, sleep, any concurrent disease, mobility).8,103
While treatment parameters (such as number of layers, types of materials, prescribed time for applying the textile wrap, duration of treatment, the effective pressure applied by the compression devices) may be prescribed, negotiation with the patient is required. For constructive outcomes, maintaining leg elevation, frequent changes of dressing and bandaging (including re-adjustment of Velcro® compression products), and maintaining of temperature of treating room are important.104–106 On-going evaluation of a patient's progress with compression intervention, ensuring the correct pressure is exerted throughout treatment, and acceptance of the treatment by the patient are all relevant. Modification of the intervention may be required in cases of discomfort. Rowland 40 used a questionnaire to demonstrate greater compliance by patients using a pneumatic pump than bandages. However, five of sixteen participants in the trial dropped out, three using the pneumatic device and two the conventional device, indicating inadequate considerations of acceptability associated with both compression modes. 40 In another study, four participants from each treatment group withdrew, from high and low pneumatic compression groups, due to discomfort and pain. 41 While pain relief and quality of life were not specifically part of the study by Taradaj et al., 41 the authors did not fully support the belief that high pressure is always well tolerated by patients. Besides the pressure tolerance of the patients, the wear acceptability of textile-based compression products depends on thermo-physiological properties of textile fabrics i.e. thermal and water vapour resistance, air permeability, water permeability, and sensory perceptions of fabrics i.e. bulk, smoothness, roughness, stickiness, prickliness, itchiness. 107
Conclusion
In general, applying some compression is better than no compression. However, no conclusive evidence currently exists to suggest which compression modality is more effective for reducing chronic oedema. Careful assessment of oedema, severity of oedema, patient details, and suitable choice of the system of compression therapy are all required. Reduction in oedema with compression intervention is more likely to be achieved if the patients apply the compression device regularly, and thus the compression needs to be acceptable. Wear acceptability i.e. effective thermal and moisture managing ability, sensorial comfort and ease of application i.e. easy to put on and take off, are critical if the number of patients withdrawing from investigations of compression interventions is to be reduced and thus effectiveness of assessment improved.
Textile properties (i.e. elasticity, stress-relaxation, thermal and moisture related) of any textile-based compression intervention are considered concurrently with physiological-based factors in reducing oedema. The textiles are not inert. Success in the management of chronic oedema is likely to be enhanced by adopting an interdisciplinary approach – i.e. physiological-based, human-based, and textile-based factors – together with patient compliance. Future reports of investigative studies need to include full details of both patients and material components of the compression device (e.g. for patients: severity, location of oedema, patient age and sex, evidence of compliance with treatment; for material components of the compression device: number of layers, fibre/textile type and structure; actual pressure exerted and known change in pressure over time). Both sets of information rely on expertise in the two different disciplines, and collaborative effort.
Footnotes
Acknowledgements
We would like to thank to Home Science Alumnae/Todhunter/Carpenter for scholarship support to the lead author.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no direct financial support for the research, authorship, and/or publication of this article. However, the primary author received a Home Science Alumnae/Todhunter/Carpenter scholarship to pursue his doctoral study related to this topic.
Ethical approval
Not applicable.
Guarantor
KN.
Contributorship
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