Diabetic foot ulcers: dressing choices

There are no special dressings that only apply to diabetic foot ulcers. Here we use the same principles as for most other types of wounds. Our dressings depend mainly on these three factors: a) how much exudate is coming from the ulcer, b) how deep the ulcer is, and c) are there signs of increased bacterial burden? Although we have repeated it many times in the chapter on diabetic foot ulcers, we will say it one more time here. Your choice of offloading is more important than your choice of dressing. 

The only dressing category we consequently do not recommend for use with diabetic foot ulcers is hydrocolloid dressings. These are occlusive and allow only for very little evaporation. It is generally accepted that hydrocolloid dressings increase the risk of infection when used on diabetic foot ulcers.

 

If the ulcer is superficial (< 0,5 cm depth), you will usually not need anything to fill the wound cavity. If there only is minor to moderate exudate, you can generally use a simple polyurethane foam dressing. If there is more exudate, you may need a foam or other dressing with better absorption properties.  

If the ulcer is > 0,5 cm in-depth, you should use some type of wound cavity filler before applying a secondary dressing over this. The wound cavity filler could be a gel, hydrofibre/(alginate, foam permeable on both sides, or a gauze. The secondary dressing could be a polyurethane foam. 

Our choice of dressing is often also affected by what we are using to offload an ulcer. When using self-adhesive wool felt, there will often not be much space in the opening of the felt to accommodate any bulky dressings. 

Infections in diabetic foot ulcers quickly lead to disaster. We, therefore, often use antibacterial dressings to prevent infections from occurring. There are many types of dressing choices with antibacterial properties. Dressings with silver are a good example of this - they can be found as contact layers, foams with silver, and even pastes containing silver. Other good alternatives are iodine products, honey products, or dressings containing bismuth. 

For some reason, diabetic ulcers often tend to have macerated ( moisture-damaged) wound edges. This may be because there can be a fair amount of exudate. There usually is a hyperkeratotic ring of hard skin around these ulcers. This thick layer of skin seems to absorb moisture, and often we see this as a whitish ring around these ulcers.   Regularly removing this hyperkeratotic edge will reduce the macerated appearance and is also essential to speeding up the healing process. You can use a ring curette or a scalpel to do this. After removing the thickened skin edges, you should apply a barrier product to protect the borders from further maceration. Traditionally thick zinc paste ( containing about 40% zinc) was commonly used. Zinc paste is by no means outdated, but modern barrier products which are see-through have slowly overtaken the market. Again, zinc paste is still considered an excellent barrier product. In fact, we believe that the zinc content protects from maceration and actually has a stimulating effect on the healing process of the skin edges. It also has anti-inflammatory and antimicrobial properties. 

What are our recommendations for dressing alternatives when treating diabetic foot ulcers?

The patient has often sought medical help because the wound is deteriorating due to critical bacterial colonization or even infection. We recommend to start off using a dressing containing a strong topical antimicrobial agent. In our experience 10% povidone iodine gauze dressings are an excellent choice to deal with a bacterial issue in diabetic ulcers. Not only is 10% povidone iodine one of the most effective agents we can use in woundcare; it is also very cheap and readily available. In the start of the treatment we recommend daily dressing changes. Teach the patient or their family how to do these dressing changes by themselves to avoid unnecessary healthcare costs. Within about 10-14 days of using povidone iodine the ulcer has often turned into a more positive direction and we can start the process of trying to encourage granulation tissue to form. Povidone iodine is not cytotoxic or harmful in other ways to the cells in the wound and you can certainly continue to use it for several weeks, gradually extending the dressing shift intervals. If you feel that the ulcer is responding well, why change the treatment? If the ulcer has improved initially but seems to stall you could try switching to another type of dressing - for example honey or a silver impregnated dressing if that is available to you. Honey certainly works well in diabetic wounds but it can sometimes be challenging to use because it may cause the wound to produce more exudate- especially in the start of the treatment. If you are using for example wool felt around the ulcer to offload it this can be soiled quite quickly when we use honey. 

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Figure 1 Saturating a gauze with 10% povidone-iodine and placing this directly into the wound cavity is a safe dressing method when your main priority is to keep microbial levels low and prevent infection. Although there has previously been some discussion about how safe povidone-iodine is, more recent articles clearly show that when used at this concentration there are no concerns about cytoxicity or any other harmful side-effects even when used for longer periods of time. 

If we look at some of the other dressings available- are there any that differ from the large crowd of dressings available?  There are a few dressings that, in our experience, are very safe choices for treating diabetic foot ulcers and that have routinely performed well in our hands.  Three of these are shown in figure 1.  However, other authors or wound care providers may have completely different recommendations.  Concerning dressing choices for the diabetic foot there are "many ways to Rome" and most types of dressings will work well as long as the dressings are changed regularly and  as long as the offloading regime is followed. 

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Figure 2  Three dressing types that somewhat stand out in the crowd of dressings. All three dressings can be cut to fit perfectly into the ulcer. Polymem is an interesting foam dressing that contains glycerol and a surfactant. The glycerol ensures optimal moisture levels while the surfactant works as a cleansing agent. Sorbact is an antibacterial dressing that traps microbes in the fibres of the mesh. Kerlix AMD resembles regular gauze but it is infact impregnated with a surfactant and an antimicrobial. In wounds which are dry it can be pre moistened, in exudatiing wounds it will be placed dry in to the wound bed. Kerlix AMD is a very cost-effective dressing as it comes in large rolls. If used sparingly one roll can last for the entire treatment of a diabetic ulcer. 

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Figure 3  Another example of a dressing choice. This patient was amputated at the base to the great toe. There were wound complications at the amputation site, and it was left to heal by secondary intention. There was no apparent infection, but it was thought wise to use a antimicrobial dressing to prevent an infection from occurring. First a self adhesive wool felt pad (Hapla) was applied and secured with Hapla tape. A contact layer containing silver was applied to the wound bed and covered with a simple foam dressing as secondary dressing. Self adhesive tape was used to secure the dressing. This is how easy many diabetic ulcers can be handled. 

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Figure 4  What dressing should we use on this pressure ulcer on the heel in a diabetic patient? Firstly, we should gently remove the fibrin on the upper side of the ulcer. There is some inflammation around the wound edges but no apparent signs of infection. We would use any type of antimicrobial dressing here - most dressings will perform well here as long as the shift intervals are not too long. What is most important here - and this is the reason for discussing this particular case - is the plan for offloading. The essential part of the treatment plan here is not the dressing but how to unload the ulcer. If available, you should use some sort of orthotic to keep the heel off the mattress. In this example, we used a heel off-loader from Maxxcare.  If you do not have such aids available, you will have to improvise with another method of offloading. 

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Figure 5 What about this case- which dressing would you recommend here? We hope that all of our readers realize that this is a severe condition. We do not see any apparent wound but see pus coming from small openings of the great toe. There are obvious signs of serious deep infection here. The patient has to be referred to a specialist clinic immediately to save the toe and limb. You could wrap the toe in an iodine dressing while under transport to the clinic or simply pack the forefoot in dry gauze. 

We have collected some of the most common dressing groups below and discuss them briefly.  When used correctly, most of these products will perform well in diabetic foot ulcers. 

Polyurethane foam dressings

Figure 6 Polyurethane foam dressings are versatile dressing choices for ulcers where we are not concerned about microbial colonization. There is really not so much you can do wrong with this type of dressing. The sponge like quality of the foam also provides some mechanical protection. However, it is not sufficient to provide off loading! In other words- if the patient has a plantar ulcer you cannot simply place  a polyurethane foam dressing on the sole of the foot and hope that it will cushion the foot sufficiently! These type of foam dressings are also useful as secondary dressings- for example if you are using a wound filer of some sort.  

Some common product alternatives: Allevyn®, Allevyn® Life, Aquacel® Foam, Askina® Foam, Biatain® Foam, Mepilex®, Permafoam® Comfort, Suprasorb P®, Tegaderm® Foam, Tielle® Foam, Kendall™ Foam Dressing, Versiva®, Kliniderm® Foam Silicone, Polymem®

Hydrogels

Figure 7  Hydrogels are usually made by mixing cellulose powder into water. They can be used as a wound filler in ulcers with little exudate. These gels are unsuitable for moderate to high exudate ulcers as they will only be washed out. Some hydrogels like Prontosan gel have antimicrobial properties. Hydrogels need to be covered with a secondary dresing  Common product alternatives: Duoderm® Hydrogel, Intrasite® Gel, Askina® Gel, Nu-Gel®Purilon® Gel, Suprasorb® G, Tegaderm® Hydrogel, Normigel®, Hypergel® , Cutimed® Gel, Aquaform® , Prontosan® Gel , Prontosan® Gel X

Pastes containing silver

Figure 8 While many fabric dressings contain silver, only a few silver pastes are available on the market. These are useful as wound fillers in ulcers with an increased bacterial burden. Image above:: Askina Calgitrol® 

Contact layers with antimicrobial properties

Figure 9 Contact layers are thin net-like materials that can be cut to fit nicely onto a wound bed. They can be used as a wound filler. Contact layers with antimicrobial properties are helpful in treating diabetic foot ulcers. Many of these contain silver, some contain iodine. Xeroform® differs from the rest as it contains the antimicrobial bismuth. 

Some common product alternatives:  Physiotulle® Ag, Acticoat® Flex 3, Acticoat Flex® 7, Acticoat® , Acticoat® 7 Atrauman® Ag, Betadine®, KerraContact® Ag, Oxyzyme®, Iodozyme®, Braunovidon® , Xeroform®

Foam dressings with silver

Figure 10  Almost all types of polyurethane foam dressings also come in a variant containing silver to provide antimicrobial properties. . Polymem® WIC differs from many other foam dressings as it can be cut and used as a wound filler. Some common product alternatives:  Allevyn® Ag, Aquacel® Ag Foam, Biatain® Ag, Mepilex® Ag, Polymem® WIC Silver, Polymem® Silver, Polymem® MAX Silver

Hydrofiber and alginates with silver

Figure 11  Hydrofiber and alginate dressings are beneficial as wound fillers. Hydrofibers and alginates behave very similar and we have therefore grouped them in the same category. All alternatives are available with and without silver impregnation. When treating diabetic foot ulcers we recommend using the silver-impregnated versions - at least in the start of the treatment until the ulcer cleans up. If the ulcer is on the dry side you can pre moisten the dressing and it will turn into a gel like consistency. In ulcers with some exudate the dressing is placed in the wound bed drily.  Some common product alternatives: Aquacel® Ag, Aquacel® Ag Extra, Aquacel® Ag+ Ekstra, Durafiber® Ag, Tegaderm®, Biatain® Alginate Ag, Melgisorb® Ag, Tegaderm®  Alginate Ag, Silvercel®, Suprasorb A®  Ag, Algicell® Ag, Algisite® Ag, Askina Calgitrol® Ag,  Sorbsan® Silver

Dressings containing iodine

Figure 12  Dressings containing iodine are used with the same indications as silver-based dressings, namely wounds with a high microbial burden.  Some of the products above contain cadexomer-iodine, and others contain povidone-iodine.  The products are available as iodine impregnated contact layers, pads, and pastes or powder.  A gauze saturated with a povidone-iodine solution will do the same thing but may need to be changed more often.  Some common product alternatives:  Inadine®, Braunovidon® Salvegaze, Iso-Betadine®, Iodoflex®, Povitulle®, Iodosorb®, Braunol® Gel, Betadine® Gel, Iodosorb® Pulver

Other antimicrobial dressings

Figure 13 Many antimicrobial dressings that are not silver-based contain PHMB (Polyhexamethylene Biguanide)  IodoFoam® is an iodine foam. We should have, of course, placed it in the iodine-based product group. Sorbact® products contain  DACC ( Dialkycarbamoyl Chloride) as the antimicrobial agent. 

The product alternatives shown above are: Kerlix® (gauze+PHMB ), Suprasorb® P X (foam+PHMB, IodoFoam® (foam + iodine), Telfa® ( pad + PHMB), Celludress® PHMB, Sorbact® products ( contain DACC)

Medical grade honey

Figure14 Honey-based products are good alternatives to other antimicrobial agents. The high sugar content not only impairs microorganisms but also seems to stimulate the cells in the wound. Honey products are available as gels, pastes, plates,  contact layers, plates and alginates impregnated with honey. It is wise to change the dressings often when using honey because the ulcers tend to exudate more, especially during the first days of using honey. It is also important to protect the wound edges from maceration with a good barrier product when using honey. Some product alternatives:  Medihoney® Antibacterial Honey Tulle Dressing, Actilite®, Melladerm® Plus Tulle, L-Mesitran® Net,

Medihoney® Antibacterial Honey Gel Sheet, Activon® Tulle, Manukadress-IG®, Manukadress® -IG MAX, Medihoney® Antibacterial Medical Honey, Medihoney® Antibacterial Wound Gel, Activon®, Mesitran® Ointment, Mesitran® Ointment S, ManukaDress-T®, Melladerm® Plus, Medihoney® Antibacterial Honey Apinate Dressing, Algivon®, Medihoney® HCS, L-Mesitran® Hydro, L-Mesitran® Hydro Border, Melloxy®, Surgihoney®

Barrier products for wound edges

Figure 15 Barrier products to protect the wound edges from maceration. Regular zinc paste is by no means outdated as a barrier product. However, transparent barrier products are increasingly popular because of their ease of application. Some product alternatives: SH Sinkpasta, Klinion® Sink 40%, Cavilon® No Sting Barrier, Cutimed® Protect, No-Sting Skin-Prep®, Silesse™Sting Free Barrier, LBF No Sting Barrier, Peri-Prep® Sensitive, Opsite® Spray, Aldanex®