Treating Diabetic Foot

There are interesting developments in diabetic foot management, but the exorbitant costs of these treatments is a deterrent, finds out Sonal Shukla

Statistics say that the greatest absolute increase in the number of people with diabetes will be in India, thanks to the title our country holds- the diabetic capital of the world. It has been estimated that upto 50 per cent of all non-traumatic lower limb amputations are performed on diabetic patients. Foot problems are important contributory factors to the high-morbidity and mortality observed in diabetic patients, and the economic impact of foot disease is substantial. The cost of treating this complication is much higher than renal or heart problem. Hence, aggressive primary and secondary prevention strategies are very essential and important.

"Foot problems are a major cause of admission to hospital for people with diabetes. One in every six diabetic worldwide will have a foot ulcer during their lifetime: that is four million people each year. Worldwide, half of all leg amputations happen to people with diabetes. Poorly treated or untreated foot ulcers can lead to the need for amputations. Through good healthcare and informed self-care, it is possible to prevent diabetes-related amputations in the majority of cases," says Dr Ajit Kumar Varma, Department of Endocrinology and Podiatric Surgery, Amrita Institute of Medical Sciences and Research Center, Kochi.

Off-loading & Footwear

The concept of off-loading the foot or relatively the ulcer-bearing area is of utmost importance in the management of the diabetic foot. The reduction of pressure to the diabetic foot ulcer is essential to treatment. According to experts, proper off-loading and pressure reduction prevents further trauma and promotes healing. This is particularly important in the diabetic patient with decreased or absent sensation in the lower extremities. Recent studies provide evidence that minor trauma (eg, repetitive stress, shoe pressure) plays a major role in the causal pathway to ulceration. "When an insensate foot is subjected to even minor trauma or to increased pressure, an ulcer can develop. Ulcers are prone to develop on areas underlying the meta-tarsal heads, and other undue bony prominences because of the misdistribution of pressure, especially with a Charcot foot and other foot deformities. Ensuring the use of proper footwear is thus an important part of a treatment programme for people with diabetes, even those in the earliest stages of the disease," says Dr Varma.

Wear the Right Size

To reduce the chances of onset of neuropathy, wearing the right footwear is crucial. It is well known that improper footwear contributes significantly to ulceration.

Experts believe that such shoes must accommodate dorsal deformities and cushion areas of high plantar pressure. In particular, they should relieve excessive pressure on areas that are prominent, such as the metatarsal heads. Shoes must also reduce shock (the vertical pressure on the bottom of the foot caused by the weight of the person) and shear (horizontal movement of the foot within the shoe).

Footwear Technologies

"Fixators help add support to deformed limbs that have been corrected while they are in the healing phases" - Dr David Nielson DPM Foot and Ankle Associates of Southwest Virginia

"An important approach of public health is to detect the level of neuropathy and advice the patient on foot care" - Dr Arun Bal Honorary Surgeon SL Raheja Hospital Mumbai

Traditionally, muscle and tissue flaps are associated with some degree of morbidity and does not have a 100 per cent success rate" - Dr Stephanie Wu Associate Professor of Surgery Rosalind Franklin University of Medicine and Science Chicago

"Charcots Foot is a severe complication of diabetes, which leads to erosions, and collapse of the foot and ankle bones" - Dr Ajit Kumar Varma Department of Endocrinology & Podiatric Surgery AIMS Kochi

New materials have been introduced in footwear technology like poron, silicon and devices have come to assess high-pressure points, which include foot scans, and in shoes scans (in shoes scans have insoles imbedded with small sensors. These are placed in the modified diabetic footwear and patient is made to walk in them. The plantar pressure computerised readings are obtained, and the correction of the raised plantar pressures identified) CAD-CAM is another technology which designs computerised footwear as per the reading of foot shape/ pressure points and walking patterns.

"Today, with the advancement in the technology shoes have a much better look to them. They have insoles that are made of bi-density material which help distribute pressure to the foot. This essentially means that the insole is made of a specific material outer layer of which has a higher density and the inner layer, which is in contact with the socks, has a lower density. Decreasing pressure and distributing it to the rest of the foot will help heal wounds faster and prevent future wounds from occurring," says Dr David Nielson, DPM, Foot and Ankle Associates of Southwest Virginia. The advantages have been in terms of decreased wounds, which decrease infections, which in return decrease amputations.

However, one major disadvantage is the cost, as the newer shoe technology is expensive and is not available frequently in developing nations like India. In the manufacturing of diabetic footwear, materials with specific qualities are used. Materials used are micro-cellular rubber, micro-cellular polymer, poron, ethyl vinyl acetate and plastazote. According to Dr Varma, the insole should distribute plantar pressure equally on its surface. Of these materials, only plastazote and the like materials can be moulded in the exact shape of the foot.

In 'offloading' specific areas of the foot, outsole modifications are made. These include the anterior, middle and posterior shoes. The different types of roccker-bottom outsole modifications are also commonly prescribed. The roccker-bottom outsole modification is a commonly used modification in diabetic footwear construction for offloading. "There are different types of roccker modification depending on the area of the foot which is required to be offloaded. Specific modifications of the insole like metatarsal bars, wing-pads, scoops, etc are also effective methods of offloading," shares Dr Varma.

Advanced Wound Care Modalities

The advent of therapeutic growth factors, gene therapy, tissue-engineered constructs, stem-cell therapy, and other drugs and devices that act through cellular and molecular-based mechanisms is enabling the modern surgeon and wound-care provider to actively promote wound angiogenesis to accelerate healing.

Vacuum Assisted Closure

Vacuum Assisted Closure (VAC) therapy today has become a common adjunctive treatment modality for diabetic foot ulcerations. VAC therapy, also known as negative pressure wound therapy, has emerged as an effective modality to help reduce the size of large, deep, diabetic wounds and help reduce the need for muscle and tissue flaps. "Traditionally, muscle and tissue flaps are associated with some degree of morbidity and does not have a 100 per cent success rate so the wound VAC is often preferred by clinicians. However, VAC therapy is expensive and not all patients can afford the therapy," says Dr Stephanie Wu, Associate Professor of Surgery and Director of Medical Education and Outreach Centre for Lower Extermity Ambulatory Research (CLEAR), Rosalind Franklin University of Medicine and Science, Chicago.

Use of a vacuum-assisted closure device of VAC promotes wound healing through the application of topical, sub-atmospheric, or 'negative' pressure to the wound base. "VAC employs the principle of continuous and/ or intermittent negative pressure which helps in improving angiogenesis. The important part of this principle is to keep the pressure constant at 125 mm Hg," says Dr Arun Bal, Specialist in Diabetic Foot Problems, Honorary Surgeon, SL Raheja Hospital, Mumbai.

The rationale for using electrical stimulation in wound healing stems from the fact that the human body has an endogenous bioelectric system that enhances healing of bone fractures and soft tissue wounds. Laboratory and clinical studies provide an abundance of support for the use of electrical stimulation in wound care. "In recent studies evaluating wound healing using electrical stimulation in neuropathic ulcers, significant differences in healed ulcer areas and number of healed ulcers at 12 weeks were found in the group receiving electrical stimulation compared with the control group," shares Dr Srinivas S, Consultant Podiatric and Diabetic foot Surgeon, Dr Mohan's Diabetes Specialities Centre, Chennai. According to Dr Varma, "Negative pressure wound therapy is not a replacement to surgical procedures. It is vital to remove all necrotic tissue prior to VAC, dressings are changed every three to five days at the bedside using sterile technique."

Regenerative Tissue Matrix

Regenerative tissue matrix is a new therapy used in diabetic foot ulcers, although it has not undergone any randomised clinical trials to date. The allograft skin is minimally processed to remove epidermal and dermal cells while preserving the bioactive components and structure of dermis. This results in a framework that supports cellular repopulation and vacularisation.

New Ultrasound Devices

Several new ultrasound devices are being used to both debride (means essentially to clean the wound) the wound and provide ultrasonic therapy. The MIST Therapy system is an ultrasonic device approved by the Food and Drug Administration (FDA) for wound debridement and cleansing. According to Dr Srinivas this MIST Therapy uses a fine saline spray that allows ultrasound to be administered directly to the wound bed without contact to the affected tissue, thus minimising potential trauma to delicate capillary buds and emerging islands of epithelium.

Tissue Growth Factors

There are numerous tissue growth factors and cytokines that are required for wound healing. For wounds that are not responding to standard conservative treatment, one may then consider tissue growth factors. If a person is to suffer from a wound, then these factors help regenerate and heal the wound. "Patients who suffer from diabetes often have a decreased ability to heal wound. Therefore, growth factors may aid tremendously in the ability to heal," shares Dr Neilson. The future of growth factor therapy in wound care is advancing rapidly. There is also increasing evidence in the literature to support the efficacy of growth factors in wounds, particularly chronic wounds, and how they can help facilitate desired healing outcomes. Several growth factors raised hope to be used in the therapy of diabetic wounds after promising experimental or small clinical trials, i.e. Epidermal Growth factor (EGF), Fibroblasts Growth Factor (FGF-2), Granulocyte-Colony Stimulating Factor (GCSF), Vascular Endothelial Growth Factor (VeGf), Insulin growth factor 'I'. But, only Platelet Derived Growth Factor (PGDF) and Epidermal Growth Factor (EGF) are being approved for clinical use as of now.

According to Dr Bal the only two types of growth factors PDGF (Platelet Derived Growth Factor) and EGF (Epidermal Growth Factor) are important and useful in treating a subset of patients who have neuropathic ulcers and these ulcers do not heal due to destruction of endogenous growth factors due to deranged wound healing. However, they are costly and have to be used in selected patients, as they are not useful in each and every wound.

Platelet derived growth factors have been studied in the past and is currently available (in India) in a topical gel form for the healing of diabetic foot ulcers. "Current studies are focused on Endothelial Progenitor Cells (EPGs) and VeGf to help with angiogenesis and wound healing," shares Dr Wu.

External Fixators

There are several brands of external fixators available in the countries like the US today. Diabetic patients often have poor bone stock and soft bones that may not facilitate the use of internal fixation. External fixations offer an alternative to help fixate the bones with compression in this patient population. "Several companies make external fixation devices. Most of them resemble the Ilizarov type external fixation developed in Russia. These help add support to deformed limbs that have been corrected while they are in the healing phases," says Dr Nielson. External fixators like EZ Frame (by Signal Medical Corp) is composed of a boot with adjustable straps, a rocker-bottom footplate, stainless steel posts, wire nuts, smooth wires and olive wires. The boot is connected to the footplate via telescoping carbon fibre rods. Additionally, one can remove the full-length tongue during dressing changes and adjust the positions of both the boot and the frame. The footplate also allows versatility in offloading ulcerated areas.

Reconstructive & Corrective Surgeries

The concept of surgical correction for the diabetic foot and ankle deformity has recently evolved as a means to correct foot deformities secondary to long standing diabetes. This re-shaping of a deformed foot or toes by surgical correction is presently being done in a few selected centres only in the US, UK, Russia, Germany, Spain, and Australia. These surgeries help to prevent the formation of callus and ulcers of the foot and thus, these surgeries can prevent amputations in diabetics. Over-riding of the big toe and crowding of toes can cause skin breakdown thus resulting in ulcers and infection. Corrective surgery is done to bring the toes to their normal position. If the foot were not properly aligned, then again the high pressures build-up in the soles would cause ulceration. 'Charcots Foot' is a severe complication of diabetes, which leads to erosions, and collapse of the foot and ankle bones, which in turn lead to marked deformities and ulcerations. Today, different types of surgical corrections are carried out to normalise the shape and function of these grossly deformed feet, informs Dr Varma.

"In patients presenting with an acute Charcot neuro-arthropathy with no apparent foot deformity, aggressive conservative treatment is the mainstay of therapy. Offloading, protection, and stabilisation are the key components of therapy," shares Dr Rajesh Kesavan, Consultant Podiatric Surgeon, Diabetic Foot Specialist, MV Hospital for Diabetes and Diabetes Research Centre. According to Dr. Kesavan, the goal of treating a patient with a Charcot deformity is to avoid skin breakdown and restore a stable foot. In patients with mid-foot deformities, the use of extra depth shoes and accommodative inlays may be sufficient in patients with minimal deformity and a stable mid-foot. Where the deformity is more severe or where the midfoot is unstable, then the use of molded shoes should be considered.

Indian Scenario

With more than 50 per cent of diabetic patients in India are between 45-55 years age group, it becomes apparent that in this economically productive age group if the patient loses his limb then it is not just only economic loss to the nation but also a social burden.

All the latest therapeutic modalities for managing diabetes foot are now available to Indian patients. Unfortunately, the above mentioned treatment modalities are fairly expensive for the average Indian patient. These treatment modalities are costly as VAC therapy costs Rs 50,000-57,000 for three weeks. Fixator treatment costs more than Rs one lakh, growth factors costs upto Rs 1200/tube of 7.5 Gms. Therefore these modalities cannot reduce the number of amputations and can be used only sparingly in India. "The most important approach for problem of public health is to detect the level of neuropathy and advice the patient on foot care/footwear. The second aspect is prompt treatment of ulcers if and when they occur," shares Dr Bal. However, Indian doctors are finding their own cost-effective ways to make their own negative pressure wound therapy. Dr Ajit Varma's method of the 'Amrita Sling technique' is being used in AIMS, Kochi as an alternative to using external fixation in Charcot surgery.

Says Dr Bal, "Diabetic foot ulcer is most devastating complication of diabetes, still un-recognised. The cost of treatment once the ulcer occurs is very high the available data shows that a patient of diabetes has to spend very large sum of money to save the leg/ foot if the ulcer takes place."

Realities like Indian medicine not having podiatry as speciality and lack of any national programme for diabetes have made the problem even severe. Whatever would be the advancement in the surgical techniques or the technology in diabetic foot management, it is the holistic approach in the long run which will help to improve the conditions.

"Strategic measures to improve overall health must focus on all the following aspects- good glucose control, detection and treatment of diabetic complications, patient education as well as specialised foot care. In the long run, a holistic approach like this is certain to be cost-effective," concludes Dr AG Unnikrishnan, Assoicate Professor, Department of Endocrinology & Diabetes, AIMS, Kochi.

sonal.shukla@expressindia.com