Kira Brown & Paige Fallu December 12th, 2017 BME 4013 ROAD: Removable Offloading Adjustable Device Abstract Diabetes is a costly and devastating disease that affected 382 million people worldwide and cost $245 billion in 2016. [1] Of these millions of people, 25% of them will develop a foot ulcer that if not cared for, can lead to an infection and amputation. [1] To successfully heal a diabetic foot ulcer there needs to be vascular management, infection management and prevention, and pressure relief. The current solutions for offloading devices have their issues, especially low patient compliance. We believe there is a need to improve the off-loading of the forefoot to heal plantar ulcerations for neuropathic diabetic patients. Our goal is to heal diabetic foot ulcers by creating a removable off-loading device to improve patient compliance, comfort and usability. To achieve this, we created ROAD, a removable offloading adjustable device that allows the patient to wear their own walking shoe by simply attaching the device. ROAD is one size fits all so it is affordable, it will improve patient compliance, and it makes it easier than ever to heal forefoot diabetic foot ulcers. Introduction i. Background When diagnosed with diabetes, there is approximately a 50% chance the patient will also have neuropathy. [2] Neuropathy occurs when there is damage to the nerves either in the hands or feet, and it causes complete loss of feeling. With the loss of feeling in the feet, the chance of forming a foot ulcer increases drastically. Ulcers form from abrasions or irritations on the bottom of the foot that callus over. If the callus is not removed, the cells within the tissue will lyse and develop hematomas under the callus. This results in a small cavity filled with fluid, similar to a blister. [2] The longer the patient waits to have the callus removed, the worse the ulcer will be. Using the Wagner Classification System, ulcers are classified from grade 0 to 5
depending on the severity of the lesion. [3] For the purpose of only offloading, grade 2 is the highest ulcer classification being used (see appendix for table). ii. Disease State Fundamentals Diabetes affected 382 million people worldwide in 2016 and is expected to grow to 552 million people by 2030 [1]. Diabetic foot ulcers (DFUs) are most commonly found on the bottom of the forefoot and under the big toe. DFUs can occur in both Type I and Type II diabetic patients. The most common cause of ulceration is repetitive mechanical forces experienced by a callus during walking. DFUs are experienced by 25% of diabetic patients [1]. More than 60% of nontraumatic lower limb amputations are caused by diabetes,but with proper foot care programs and monitoring, amputation rates can be decreased by 45-85% [4]. iii. Need Discovery This need was discovered by interviewing Podiatrist Dr. Chris Fallu. Dr. Fallu suggested improving an insole device PegAssist by DARCO. The PegAssist is used for off-loading the plantar-aspect of the foot after surgery, or when wounds are present, to prevent plantar lesions, plantar ulcerations, and/or pressure points. When looking more into this device and the reviews, it was discovered that when a peg was taken out the pegs around it would also fall out, some users experienced more pain when wearing the insole and others thought there was more pressure put on their wound. Since this device has a broad range of uses, more offloading devices were researched to see if there was a better solution to prevent wounds from worsening. When researching we found that offloading devices are used a lot of the time for healing of foot ulcers, but there were issues with a lot of the devices out there. Non-removable devices will heal the ulcers fast and effective but, a lot of doctors do not want to prescribe them to their patient because it is extremely uncomfortable for the patient to wear for up to 7 weeks. Looking at removable devices, most are hard for patients to wear because they would need a cane or a walker for balance. With this research we decided to focus on creating a off-loading device to heal neuropathic diabetic foot ulcers that is easy and comfortable for the patient to wear, does not require a cane/walker, and is removable so it increases patient compliance.
iv. Current Treatment Options 1. PegAssist by DARCO : An insole system with removable pegs to improve offloading. The device is worn in surgical boots or offloading shoes. a. 33-60% pressure relief of the forefoot Advantages: Can be ordered online and patients fit at home Good pressure relief for an insoles Easy to use Comfortable Disadvantages: Pegs fall out Some cases caused more pressure and lead to more injury Some not reusable 2. Orthowedge : A half shoe that only makes contact with the ground at heal and middle of the foot. a. Heals 55-90% of ulcers b. Takes 6-18.5 weeks to heal the ulcers c. 64-66% of pressure relief of the forefoot Advantages: Can be combined with insoles to increase pressure relief Removable Good amount of offloading Disadvantages: Pressure is displaced to midfoot and heel, not evenly distributed Can dorsiflex ankle which decreases offloading Open toed shoe can lead to more injury to skin Must have a cane or walker because of bad balance Leads to bad patient compliance, reason for large range of weeks till healed
3. Integrated Prosthetic and Orthotic System (IPOS) : Is a rocker shoe that is curved at the heel and toes a. Heals 55% of ulcers b. Takes approximately 7.5 weeks to heal c. 55-65% pressure relief of the forefoot Advantages: Forefoot does not contact the ground Cost effective Comfortable, high patient compliance for the ones who can walk in it Removable Disadvantages: Patients must have good balance, if not they cannot wear Requires dorsiflexion 4. Healing Sandal : Is a total contact orthotic a. Heals 45-65% of ulcers b. Takes 6-8 weeks to heal ulcers c. 35-45% Pressure relief without insole system Advantages: Lightweight design More aesthetically pleasing High patient compliance Disadvantages: Less environmental protection Open toed shoe can lead to more injury to skin Poor control of foot motion Dorsiflexion is possible [5] for % of healed ulcers, time til healed, and pressure relief %.
v. Market Analysis In 2016 Diabetes affected 383 million people worldwide. This number is expected to increase to 552 million people by 2030. [1] Approximately 50% of patients will have neuropathy as a symptom of diabetes. [2] And 1 in 4 patients with diabetes will develop a foot ulcer in their lifetime. [1] Diabetes cost $245 billion in the United States and $15 billion just to the care of diabetic foot ulcers. [1] The cost of diabetic foot ulcers is more costly than the 5 most expensive cancers. [6] When visiting the podiatrist for check ups, insurance only pays 80% every 6-months. If a patient has a foot ulcer they will need to see the podiatrist every couple of weeks. vi. Stakeholders The stakeholders involved in this need are Doctors, (podiatrist, primary care provider or family doctor) diabetic patients with neuropathy, caregivers (family members, spouse, in-home RN, nursing home RN), and insurance companies. There are stakeholder conflicts that can occur when dealing with the current solutions. As previously stated, most patients do not want a total contact cast because it is non-removable and can be uncomfortable. Because of this, the other options of removable devices can lead to safety issues. Rocker bottoms are difficult to walk in for obese and/or elderly patients because they must have good balance. It can also be difficult for caregivers to help the patient walk around with a shoe or boot on for the next few weeks or months. Design Concept i. Selection Process From the previous research and difficulties with the current solutions, we decided to create a device that is attachable to the patient s walking shoe. This allows ROAD to be comfortable, and easy to wear. The device is one-size fits all, affordable, and for type 0 to type 2 ulcers. To create our device it is comparable to the orthowedge in that it is a type of half shoe but with improved balance to increase patient compliance. ii. Justification Walking shoes have a 25% offloading of the forefoot without insoles, so we are hypothesizing that attaching an offloading device to the walking shoe will greatly increase
offloading. Comparing to the orthowedge, we are hoping to have similar forefoot offloading of at least 65%. Since we want the device to be cost-effective, we decided to make it one-size fits all by the width and length easily adjusting to the correct size. Comparing men s and women s shoes, the width only needs to have a difference of 2 and the length 3. To make it an offloading device, it will be 2 high as seen in fig. 2. This height was decided from a previous study that concluded the higher the device the greater the offloading, but 2 is best for patient safety [7]. To improve the issue of patient compliance with offloading devices, besides being able to wear own walking shoe, ROAD has an extended bottom so it will not affect the balance of the patient. When we test this device we will be able to determine how much it does affect the gait cycle and how we can further improve the design. iii. CAD Figures Figure 1: Top view with measurements of ROAD
Figure 2: Side view with measurements of ROAD iv. Sketches Figure 3: Sketch of how patients walking shoe fits into ROAD
Figure 4: Sketch of side view to show adjustable bottom (measurements not correct) Figure 5: Sketch of ROAD pieces, bottom and sides. Methods i. Equipment Needed For the fabrication of the device, a press mold will have to be developed and a manufacturer with press molding capabilities will need to be found. Other equipment needed includes the use of the MTS machine, Fujifilm Pressure Paper, and computer simulations. Carbon rubber and blown rubber are shaped using press molds. The MTS machine, Fujifilm Pressure Paper, and computer simulations are to be used in testing of the device.
ii. Projected Tests, Experiments and Protocols Projected testing includes quantitative measuring and analysis of offloading of device compared to current market solutions with the use of Fujifilm Pressure Paper. Different angles of the foot will be tested as well as the necessity of the extended bottom. The MTS machine will be used to measure the loading capabilities of the materials and device. This will help determine the maximum weight of the device. Another projected test is the use of computer modeling to simulate a walking gait to look at the structural build of the device and the potential bending points in the design. iii. Materials Materials for the device were chosen on mechanical properties of materials. The outer materials will be made of a combination of blown rubber and carbon rubber. The upper part of the device will be made of a molded plastic with an interior coating of ethyl vinyl acetate. With the combination of both blown rubber and carbon rubber, the device will have the flexibility and durability that is required to bear the weight of the user. The addition of blown rubber will also reduce the weight of the device by reducing the amount of carbon rubber needed. For the upper, the molded plastic will provide a stable exterior for the user s ankle and for the attachment of the velcro. The ethyl vinyl acetate interior lining of the molded plastic will provide a cushion space between the device and the wearer s shoe. Project Relevance and Broader Impact ROAD is an innovative way to offload the forefoot to heal neuropathic diabetic foot ulcers. There is no other device on the current market that allows a patient to wear their own walking shoe to reduce pressure of the forefoot; especially not a one-size-fits-all device. This leads to improved patient compliance and allows independent use compared to other devices. With testing, ROAD will improve to further meet the customer needs and successfully heal ulcers.
Timeline and Project Schedule Budget i. Table Item 1 device Carbon Rubber $0.35 Blown Rubber $0.30 Ethyl Vinyl Acetate $0.45 Polyurethane $5.40 Velcro $0.80 Glue $0.10 Pinch Lock $0.50 TOTAL $7.90
ii. Funding Source We are hoping to receive funding for ROAD through Lawrence Tech and Lawrence Tech Biomedical Engineering Department and will submit a budget and justification soon. Other i. Appendices Figure A: Wagner classification system chart. Figure B: Wagner classification depth comparison graphic.
ii. Extra Images or Drawings Figure C: Our original sketch when brainstorming design ideas iii. References [1] Cancelliere, Pasquale (2016) Current Epidemiology of Diabetic Foot Ulcers. International Journal of Diabetes [Article] Available: http://www.opastonline.com/wp-content/uploads/2016 /07/current -epidemiology-of-diabetic-foot-ulcers-ijd-16-001-1.pdf [2] Peripheral Neuropathy (2013) American Diabetes Association. [Website] Available: http://www.diabetes.org/living-with-diabetes/complications/neuropathy/peripheral-neuropathy.ht ml [3] Snyder, R.J, et al (2010) Consensus Recommendations on Advancing the Standard of Care for Treating Neuropathic Foot Ulcers in Patients With Diabetes. [Image] Available: https://www.podiatrytoday.com/files/abh_wounds.pdf [4] American Podiatric Medical Association. (2016) Diabetes By The Numbers.[Image] Available: http://naturallyreversediabetes.com/diabetes-home-remedy/adult-diabetes/?processid=56999370 00212610
[5] Cavanagh, P.R., Bus, S. A. (2010, Sep.) Off-loading the diabetic foot ulcer prevention and healing. Journal of Vascular Surgery. [Article] Available: http://www.sciencedirect.com/science/article/pii/s0741521410013285#sec3 [6] National Diabetic Foot Care Audit (2014-2016) NHS Digital. Available: https://digital.nhs.uk/catalogue/pub23525 [7] Van Schie, C., Ulbrecht, J.S., Becker, M.B., Cavanagh, P.R. (2000) Rocker Shoes and Pressure Distribution. Foot and Ankle International Available: https://www.ncbi.nlm.nih.gov/pubmed/11128014