In our previous articles in Wound Care and Hyperbaric Medicine we discussed the evaluation and management of "problem" wounds and the roles of hyperbaric oxygen for them (Figure 1).1-12 Regardless of immediate results, what really counts is the durability of the healed wound and the restoration of function. This makes the prevention of new and recurrent wounds an essential component of the care provided to the patient. The adage “An ounce of prevention is worth a pound of cure” is nowhere more true and appropriate than in the healing of the diabetic foot wound.
Often during hospitalization and subsequent skilled nursing care, the patients’ activities are so controlled that healing is achieved. When the patients return to their home environments and the restoration of their prewound activities, however, the wound recurs. This paper is the first in a series of five for Wound Care and Hyperbaric Medicine that expounds on the prevention of new and recurrent wounds in the lower extremities. This initial paper discusses myths and misconceptions about healing of the foot wound — especially in the diabetic — and introduces the four preventive measures for new and recurrent wounds, each of which will become a subsequent article.
Although this paper and the subsequent papers in this series are primarily directed at diabetic foot wounds (DFWs), it is equally applicable to problem foot as well as other lower-extremity wounds in patients who are not diabetic. This concept was appreciated by Dr. William Wagner, for whom we are indebted because of using his nearly universally accepted diabetic foot ulcer grading system. In his initial paper on the subject, he limited his grading system to diabetic foot ulcers.13 Two years later he revised his algorithms to include foot ulcers in nondiabetics as well.14
Foot wounds in diabetics and patients with peripheral artery disease are common — 10 to 100 times more so than those without these problems. About 1 in 15 diabetics will develop a foot wound sometime during their lifetime.15 Approximately 85 percent of lower-limb amputations are preceded by nonhealing foot wounds.16 The majority of foot wounds are easy to manage and resolve completely in their incipient stages. We computed the costs to prevent a foot wound to be 1/50th of the costs to treat one.
Once a foot wound is healed, the majority — that is, more than 90 percent of the cases in our experiences — of new foot wounds occur because of one or more confounding factors, which include the following: 1) underlying deformity (bone, bursa and/or cicatrix), 2) deep infection (especially of the deformity-related structures just mentioned) and/or 3) ischemia-hypoxia.17
Table 1. Why wounds-Especially of the feet-Arise or Recur
|Comfounding Factors, i.e. the "Troublesome Triad"
||Off---load, surgical correction
||One or more of these factors found,in 90% of the patients hospitalized with diabetic foot ulcers we studied
||Inflammation, cell death
||Impairment of metabolic processes, cell death
||Revascularization, hyperbaric O2
||Inhibits generation of sub-states; lowers resistance
||Supplements, G---tube, hyper alimentation
||Quantified with albumin & prealbumin measurements
||Hastens atherosclerosis fosters infection,
||Insulin, medications, weight loss
||Quantified with blood glucoses & HbA1c
||Enzymatic degradation of wound healing precursors
||Debridements, hygiene, tetracyclines, Promulgram®
||Postulated to stall wound healing; but questionable
|Collagen vascular diseases
||Vasculitis, primary endothelial dysfunction
||Wound care, live with chronic---stable wounds
||Distal toe & foot amputation; oeen fail; lead to BKAs
||O2 diffusion distance through tissue fluids
||Elevation, elastic wraps, diuretics
||O2 diffuses from capillary to cells through tissue fluids
||Hinders healing & infection defenses
||Vitamin C, antibiotics,
||Interferes/halts inflammatory responses
||Decreased O2 delivery/availability to tissues
||Iron supplements, erythropoietin, transfusion
||May benefit perfusion; less cell mass in sluggish flow
|Chronic kidney disease
||Unhealthy environment for metabolism
||Medications, dialysis, renal transplant
||Edema & anemia; immunosuppressers (transplants)
||Hampers generation of proteins; eliminates wastes
||Diet, medications, transplants
||As above for chronic kidney disease
||Uncontrolled infections; life/ limb threatening
||Antibiotics, transfusions, vasopressors
||Associated with adrenal shutdown, splenectomy
These are labeled confounding factors because they are often not appreciated to the extent necessary to prevent new or recurrent wounds, overlooked or outright discarded. This latter consideration is especially important in the noncompliant patient; and/or the patient lost in the exigencies of eponymic health maintenance organizations (HMOs) and insurance payers authorization; and increasingly onerous documentation requirements. Each confounder has defined techniques for diagnosis and specific interventions for management and has been mentioned in the first author's previous publications.1,18
It has been reported that 60 percent of patients with a diabetic foot wound will develop a recurrent wound.19,20 Problems such as malnutrition, adequate glycemic control, matrix metalloproteinases, collagen vascular diseases, lymphedema, requirement for steroids/immune-suppressors, anemia, chronic kidney disease, liver failure and immune deficiency disease that interfere with healing are usually adequately managed during hospitalizations, but for the reasons discussed in the preceding paragraph often lack adequate posthospitalization follow-up care (Table 1). Succeeding articles in this series of wound-prevention articles will further elaborate on the four prevention strategies.
Misconceptions Regarding Prevention of New and Recurrent Diabetic Wounds
1. Once a foot wound heals, the wound will inevitably recur after activity is resumed.
Fact #1: The reasons for this misconception are the high recurrence rates observed when activity is resumed after wounds heal with hospital management, rest and offloading and as is especially observed with malperforans ulcers after total contact casting.21 Without attention to the underlying deformities and the other wound confounders, new and recurrent foot wounds are likely to occur.
Fact #2: With attention to managing deformities, muscle imbalances, wound hypoxia and infection — and initiation of prevention strategies (as will be discussed in subsequent articles), new or recurrent wounds can be prevented.
Fact #3: Furthermore, once a wound is healed, the metabolic demands to maintain the wound site in a healthy condition are but a small fraction of what was required for healing and infection control. As much as a 20-fold increase in perfusion and metabolic activity compared to the resting, healed state may be required.22 The increased perfusion arises from redistributing the human body’s limited blood volume (about 5 liters) from noncritical — in terms of perfusion — to the wound site in response to sympathetic nervous system activity and cytokines.
Even in the presence of peripheral arterial disease, the approximately 1/20th reduction in perfusion and metabolic activity is usually sufficient to meet the minimal metabolic demands of the noncritical tissues. Consequently, with the prevention strategies, healed wounds, especially of the feet and ankles, remain healed regardless of marginal perfusion to these areas.
Fact #4: Patient compliance is a crucial factor in avoiding new and recurrent foot wounds. Although much is written about the importance of compliance, little information is available on how to quantify it. Our next article for Wound Care and Hyperbaric Medicine, which will focus on patient education, will offer much information on measuring patient compliance and how to use this information for managing patients.
2.Preserving the foot has little functional significance in the marginal ambulatory.
Fact #1: A lower-limb amputation in the minimal ambulator who had been independent with activities of daily living may increase the energy demands for walking with a prosthesis to the point that the patient requires assisted living.
Fact #2: Energy demands for walking with a prosthesis, as measured by oxygen consumption, essentially double with a below-knee amputation and more than triple with an above- knee amputation.23,24
Fact #3: Additionally, weakness and arthritic changes in the upper extremities may make donning and removing the prosthesis difficult, if not impossible. With such comorbidities, the use of crutches or front-wheel walkers may be markedly restricted.
Fact #4: Rehabilitation and confidence in using a prosthesis may take a year or more to maximize strength, balance and endurance. In patients with cardiac and pulmonary comorbidities, oxygen-consumption demands for walking with a prosthesis may exceed the patients’ maximal aerobic capabilities.
Fact #5: Although an amputation may appear to be immediately cost-effective by expediently moving a patient from the acute hospital setting to a lower level of care, the total costs for managing the wound may be overall cost beneficial. For example, expenses for surgery, prostheses and rehabilitation exceed $50,000 during the initial 18 months after an amputation.25,26
Fact #6: Challenges for fitting the prosthesis are anticipated in the patient with cardiac and renal impairments where marked variations in stump volume occur. This can be further compounded by stump tissue atrophy, knee joint contractures, short stump lengths and lack of soft tissue padding over the end of the tibia.
3.Once a leg is amputated, amputation of the other limb will soon follow.
Fact #1: If the lower limb amputation is due to severe, diffuse, bilateral peripheral artery disease that cannot be revascularized, this statement may be true. With wound- prevention measures (which will be subsequently presented in future editions of Wound Care and Hyperbaric Medicine), however, contralateral lower-limb amputations can usually be avoided. This observation is supported by our previous discussion of the great differences in perfusion and metabolic activity to heal a wound in contrast to the steady state, nonwound, noninfection state.
Fact #2: If the lower-limb amputation is due to wounds associated with uncontrollable deformities such as Charcot neuroarthropathy or distal leg-ankle fracture nonunions, subsequent amputation of the other extremity is highly unlikely in the absence of new problems in the remaining extremity.
Fact #3: In the situations in which a lower-limb amputation becomes necessary, be it unilateral or for the opposite limb in the patient who is already an amputee, one or more criteria for amputation are invariable present. Undoubtedly, one of the most important is uncontrollable pain. Other reasons for the lower-limb amputation include gangrene of the foot, deformity severe enough that functional use of the extremity is not possible, nonhealing wounds secondary to vasculitis in patients with collagen vascular diseases and a subset of diabetic patients with foot wounds infected with methicillin-resistant Staphylococcus aureus. In this latter situation we have observed that as long as the patient remains on antibiotics, the wound appears healed, but once the antibiotics are discontinued — even after months of therapy — the wound recurs, usually moving proximally up the foot and leg. It appears this subset of diabetic patients is deficient in host factors needed to eradicate residual occultly infected tissues at the original wound site.
4.Care of the limb-threatening wound in the diabetic is different than in the patient without diabetes.
Fact #1: The severity of the wound is the overriding consideration for making decisions about management of the wound. Our Wound Score, which integrates information from the four most commonly used wound-grading systems, objectively grades wounds in a user-friendly format that determines the severity of the wound and provides the basis for management (Table 2). If the wound is in the “healthy” or “problem” wound categories, management using the strategies of 1) optimal wound base management, 2) appropriate protection and stabilization, 3) medical management including antibiotics, 4) suitable wound dressing agents and 5) adequate perfusion-oxygenation from our previous reviews resulted in more than a 90 percent positive predictive value for wound healing.18,27,28 It is irrelevant whether the patient is diabetic or not with use of our wound grading and management strategies.
TABLE 2. The User-Friendly 0 (Worst) to 10 (Best) Wound Score to Objectively Categorize Wounds
Fact #2: If the wound is serious enough that a lower-limb amputation becomes an option for management, then additional patient information — such as their health status and their goals — is required. Like the Wound Score, these scores are each based on five assessments graded from 2 (best) to 0 (worst) and have been previously described in Wound Care and Hyperbaric Medicine (Tables 3 and 4).1,18 These scores help to justify the decision whether to salvage the foot or recommend a lower-limb amputation and apply equally well to the diabetic as well as the nondiabetic.
TABLE 3. Wellness Score Quantity Patients' Health Status
TABLE 4. Goal Score Quantifies Patients' Desire to Avoid Lower Limb Amputation
Fact #3: The majority of patients with venous stasis disease ulcers are not diabetic. Again, management that utilizes the five strategies as described previously is employed. With venous stasis ulcers, the protection and stabilization strategy with compression dressings is a key element. Management of the wound base is also essential. When the ulcers are chronic and seemingly refractory to treatment, they require operating-room debridement to remove an impervious layer of cicatrix between the ulcer base and the underlying healthy vascularized tissue that may extend through the subcutaneous tissue to the underlying fascia (Figure 2). Once a healthy granulating wound base develops, split- thickness skin grafting is almost uniformly successful.
FIGURE 2. Cicatrix Excision from a Refractory
Legend: Nearly a quarter-inch (6 mm) thick layer of scar tissue has developed between the ulcer base and the underlying fascia. This is an impervious barrier between the ulcer base and the healthy underlying muscle fascia. The ulcer had failed to improve because of lack of perfusion to bring the necessary elements for wound healing to the surface of the ulcer.
Elevation, compression wraps, enzymatic debriding agents and bioengineered wound dressings had not been successful due to the impenetrability of the layer of cicatrix.
5. Neuropathy is the primary reason foot wounds fail to heal.
Fact #1: Neuropathy with absence of sensation is an indirect cause of wounds. It, in itself, does not cause wounds. Foot wounds are caused by stresses such as shear, pressure concentrations and/or trauma that exceed the skin’s ability to mitigate the aggravating factors. Contributing causes as previously mentioned include underlying deformities and ischemia-hypoxia.
The main concern of neuropathy-associated wounds is that it delays diagnosis. In the absence of pain, the wound may go unnoticed or be totally disregarded until others complain of odor, ascending infection develops or the patient becomes septic.
Other neuropathy contributing factors to wounds include 1) muscle imbalances (such as those leading to clawed toes) from motor neuropathy (these concentrate pressure stresses at the deformity sites); 2) excessive shear stresses from impaired proprioception (wounds occur with ambulation and shoe wear); 3) increased vulnerability of the skin to breakdown due to autonomic nervous system dysfunction (this leads to skin dryness, atrophy, loss of elasticity and wasting away of underlying soft tissue padding).
Fact #2: Neuropathy is not the reason a wound fails to heal. Paradoxically, neuropathy may facilitate wound healing by increasing blood flow through loss of autonomic nerve function controlling vasoconstriction. This leads to hyperperfusion as is so often in association with Charcot neuroarthropathy. Another reason there may be increased blood flow is that the blood vessels are calcified (atherosclerotic) and do not constrict in response to sympathetic nervous system stimulation.
Fact #3: Diabetic foot wounds in the presence of sensory neuropathy are typically the easiest to manage because dressing changes and wound debridements can be optimized since they do not lead to discomfort for the patient.
Fact #4: Even more convincing evidence to dispel the misconception that neuropathy is a direct cause of foot wounds is the observation that once the wounds are healed in patients with sensory neuropathy, recurrences are the exception in the well-motivated patient. This is attributed to compliance of the patient for the prevention measures (e.g., education, foot skin and toenail care, protective footwear and proactive surgeries), which each will be discussed in subsequent articles in Wound Care and Hyperbaric Medicine.
6. It is difficult to predict which patients are prone to wound development in their feet.
Fact #1: Consensus workshops uniformly agree that five risk factors — especially in diabetics — need to be recognized and appropriately addressed to prevent new and recurrent wounds in patients prone to develop ulcerations in their feet.29-32 The risk factors are: 1) deformity, 2) peripheral vascular disease, 3) history of previous wound, 4) previous amputation and 5) neuropathy
Fact #2: Other risk factors such as obesity, diabetes mellitus, malnutrition, smoking, myopathies, loss of proprioception (as in Charcot neuroarthropathy), collagen vascular diseases, inappropriate activities, improper footwear and compliance can also be contributing factors to new and recurrent foot wounds. Many of these can be recognized with an appropriate evaluation of the patient; several are remedial and manageable with appropriate care and counseling such as diabetes, malnutrition and smoking. Smoking and compliance will be discussed in subsequent articles in this series. Myopathies and loss of proprioception are factors rarely mentioned as causes of foot wounds. Because of abnormal gait mechanics leading to disproportionate shear stresses with ambulation, foot wounds are prone to develop in patients with these problems.
7. The patients’ physicians and other caregivers have little to offer in terms of preventing new or recurrent foot wounds.
Fact #1: It is crucial that appropriate medical follow-up be done to prevent new and recurrent foot wounds. Four items are essential for the follow-up evaluations (Figure 3): They include 1) patient education, 2) foot skin and toenail care, 3) proper protective footwear and 4) proactive surgeries. Each needs to be an element of follow-up evaluation and will be the subject for future articles in this series.
Fact #2: The more risk factors for foot wounds (i.e., deformity, previous wound, previous infection, peripheral artery disease and neuropathy) that are present in a patient, the more important follow-up evaluations are.
Fact #3: Follow-up intervals need to be tailored to the patient’s needs. For some patients, follow-ups may need to be done only once or twice a year, whereas in others they may need to be done at biweekly intervals to prevent new or recurrent foot wounds. As expected, there is an inverse relationship between the recommended frequency of patient follow-ups and patient compliance.
FIGURE 3. The Four Strategies to Prevent New and Recurrent Foot Wounds
Legend: Prevention strategies are fundamental for preventing new and recurrent foot wounds. Each complaints the others. Each evaluation and management of a patient with one or more of the risk factors predictive for foot wounds (namely deformity, neuropathy, peripheral artery disease, previous foot wound, or partial foot/toe amputation) should always address all of the four strategies. The prevention of a wound is highly cost effective versus dollars and dollars to cure it. (i.e. "An ounce of prevention is worth a dollar of cure.") Each strategy will be seperately discussed in our succeeding Wound Care & Hyperbaric Medicine articles.
Preventive medicine is assuming increasingly important roles in patient management. We previously published articles on risks factors, indirect and direct causes of diabetic foot wounds and the four-pronged approach to preventing diabetic foot ulcers. 33,34 This paper expands on these topics and lays the foundation for separate articles on each of the preventions strategies.
Periodic examinations with care providers is necessary in integrating the prevention strategies. Whereas annual physical examinations rely largely on laboratory data to make management recommendations, the prevention of new and recurrent foot wounds is dependent on examination
of the patient’s feet. As a further contrast, much of the preventive care offered to the patient from laboratory data is achieved through medications. For prevention of foot problems, the care is largely hands-on, such as skin and toenail care, selection of protective footwear and proactive surgeries. There are mutual concerns, of course, such as smoking history and obesity that are fundamental components of an examination and have ramifications for the entire body as well as the feet. Consequently, there is no better portal for prevention of new and recurrent foot
wounds than examination of the feet. Awareness of the five major risk factors (deformity, previous wound, previous amputation, peripheral artery disease and neuropathy) for developing foot wounds is the examination starting point for any patient to prevent new and recurrent foot wounds.
In the introduction, the magnitude of foot wound problems was mentioned. Examination of cost considerations give added justification for being proactive in preventing new and recurrent foot wounds. If a foot wound evolves to a necrotizing soft-tissue infection with underlying deep infection and/or osteomyelitis, hospitalization is required to save life and limb. The hospitalization for a serious diabetic foot wound typically exceeds $30,000. One or two surgeries at an estimated $10,000 each and 10 days of hospital care at $2,000 a day is an example of how quickly hospital care charges amass. Conversely, a lower-limb amputation is not necessarily a cost-beneficial approach to the foot wound problem. More than 15 years ago the estimated cost of a below-knee amputation with 18 months of follow-up including prosthesis costs and rehabilitation was more than $50,000.25,26 Today the total expenditures may be double this amount. For example, the charges for a below-knee prosthesis is about $15,000, and the computerized knee component alone for an above-knee prosthesis is $50,000.
The costs of hospital care and the prostheses do not represent the complete long-term costs and emotional toil a lower-limb amputation accrues. These “costs” can arise from inability to return to gainful employment and/or continue in an independent living status. Each has its own detriment to a patient’s emotional status and self-worth. Assisted living or skilled nursing costs $3,000 to $5,000 or more a month. The maintenance of independence in a marginal ambulator with their limbs intact, but managing to continue in an independent living status is far superior to the above options.
The donning and removing of a prosthesis and walking with the additional weight of the prosthesis plus loss of lower- limb proprioception may confine the patient to being able to use only the prosthesis to do transfers. Such scenarios can be emotionally devastating for the patient and extremely challenging for the patient’s family. Hence, the prevention of new and recurrent foot wounds extends beyond cost considerations alone.
A final consideration: Is it fair to discriminate levels of care between diabetics and nondiabetics (as mentioned in the fourth misconception discussed previously) with actual or impending foot wounds? Presently, there are major discrepancies between what care options are available through Medicare/CMS provisions and other third-party insurance providers for diabetics and nondiabetics. Two obvious examples include the provision of protective footwear for diabetics in accordance with the Diabetic Footwear Bill and the use of hyperbaric oxygen for specific diabetic foot wound problems (e.g., diabetic foot ulcers not improved with surgery and antibiotics for 30 days or more that involve deep abscess and/or osteomyelitis).
As noted before, Wagner expanded his diabetic foot grading system two years after his original publication to include nondiabetic foot wounds.14 Wagner differentiated only between the diabetic and nondiabetic using ankle-brachial indexes greater than 0.45 in the diabetic versus 0.35 in the nondiabetic for making decisions about limb salvage. Other than that, his algorithms for management were identical. Thus, we advocate equal diligence in preventing new or recurrent foot wounds regardless of whether or not the patient is diabetic.
The prevention of new and recurrent foot wounds is more than a cost-benefit consideration. Of all the preventive measures (not withstanding immunizations) used in medicine and surgery, the prevention of new and recurrent foot wounds is one of the most predicable and cost beneficial. Many misconceptions exist about foot wounds and their prevention. This article presents seven examples and provides facts and answers to dispel the misconceptions. Additional articles to follow in this series will elaborate on the specific strategies to prevent new and recurrent foot wounds and will include the subjects of patient education, skin and toenail care, protective footwear and proactive surgery. Although much attention has been given to this subject in the diabetic, we feel that all foot wounds — especially in the nondiabetic with peripheral artery disease — deserve the same attention as for the diabetic.
- Strauss MB, Miller SS, Aksenov IV. Challenges of Wound Healing. Wound Care and Hyperbaric Medicine, 2011; 2(1):28-37.
- Strauss MB, Miller SS. Preparation of the Wound Base: The Science and Art of Debridement. Wound Care and Hyperbaric Medicine, 2011; 2(2):14-30.
- Strauss MB, Penera KE, Miller SS. Protection and Stabilization of the Wound. Wound Care and Hyperbaric Medicine, 2011; 2(3):33-53.
- Aksenov IV, Strauss MB, Miller SS. Medical Management of the Patients with Problem Wounds. Wound Care and Hyperbaric Medicine, 2011; 2(4):13-32.
- Strauss MB, Miller SS, Aksenov IV. Making the Scoring of Wounds Objective. Wound Care and Hyperbaric Medicine, 2012; 3(1):21-37.
- Strauss MB, Miller SS, Aksenov IV, Manji K. Wound Oxygenation and an Introduction to Hyperbaric Oxygen Therapy: Interventions for the Hypoxic/Ischemic Wound. Wound Care and Hyperbaric Medicine, 2012; 3(2):36-51.
- Strauss MB, Hart GB, Miller SS, et al. Mechanisms of Hyperbaric Oxygen, Part 1. Wound Care and Hyperbaric Medicine, 2012; 3(3):27-42.
- Strauss MB, Hart GB, Miller SS, et al. Mechanisms of Hyperbaric Oxygen, Part 2. Wound Care and Hyperbaric Medicine, 2012; 3(4):45-66.
- Strauss MB, Lew DC, Miller SS. The Wagner Wound Grading System: What is it? What are its Ramifications for Hyperbaric Medicine? Wound Care and Hyperbaric Medicine, 2012; 3(4):38-44.
- Strauss MB, Manji K, Dierker RL, et al. Wound Dressing Agents. Wound Care and Hyperbaric Medicine, 2013; 4(1):41-69.
- Strauss MB, Manji KA, Miller SS, Manji AA. Bursa and Callus: Friend or Foe. Wound Care and Hyperbaric Medicine, 2013; 4(2):19-28.
- Strauss MB, Miller SS, Nhan L. The End-Stage Wound: Its Determination and Management. Wound Care and Hyperbaric Medicine, 2013; 4(4):19-26.
- Wagner FW. Classification and treatment program for diabetic, neuropathic and dysvascular foot problems. Instructional Course Lectures 28. American Academy of Orthopaedic Surgeons. 1979; 28:143-165.
- Wagner FW. The dysvascular foot: a system of diagnosis and treatment. Foot & Ankle International. 1981; 2(2):64-122.
- Reiber GE, Ledous WE. Epidemiology of diabetic foot ulcers and amputations: evidence for prevention, The evidence base for diabetes care. London: John Wiley & Sons; 2002:641-65.
- Mayfield JA, Reiber GE, Sanders LJ, et al. Preventative foot care in people with diabetes. Diabetes Care. 1998; 21(12):2161-77.
- Strauss MB, Moon H, Craig AB, et al. The Incidence of Confounding Factors in Diabetes Mellitus Patients Hospitalized for Diabetic Foot Ulcers. Wounds, 2016. In Press.
- Strauss MB, Aksenov IV, Miller SS. MasterMinding Wounds, North Palm Beach, FL: Best Publishing Company; 2010.
- Helm PA, Walker SC, Pullium GF. Recurrence of neuropathic ulcerations following healing in a total contact cast. Arch Phys Med Rehabil. 1991; 72(12):967-70.
- Uccioli L, Faglia E, Monticone G, et al. Manufactured shoes in the prevention of diabetic foot ulcerations. Diabetes Care. 1995; 18(10):1376-1378.
- Frigg A, Pagenstert G, Schäfer D, et al. Recurrence and prevention of diabetic foot ulcers after total contact casting. Foot Ankle Int. 2007; 28(1):64-9.
- Strauss MB. Diabetic foot and leg wounds: principle, management and prevention. Primary Care Reports. 2001; 7:187-98.
- Walters RL, Perry J, Antonelli D, Hislop H. Energy cost of walking of amputees: the influence of level of amputation. J Bone Joint Surg Am. 1976; 58(1):42-6.
- Pinzur MS, Gold J, Schwartz D, Gross N. Energy demands for walking in dysvascular amputees as related to the level of amputation. Orthopedics. 1992; 15(9):1033-6.
- MacKenzie EJ, Jones AS, Bosse MJ, et al. Health-care costs associated with amputation or reconstruction of a limb- threatening injury. J Bone Joint Surg Am. 2007; 89(8):1685-92.
- Mackey WC, McCullough JL, Conlon TP, et al. The costs of surgery for limb-threatening ischemia. Surgery. 1986; 99(1):26-35.
- Strauss MB, Strauss WG. Wound scoring system streamlines decision-making. BioMechanics. 1999; VI(8):37-43.
- Borer KM, Borer Jr KC, Strauss MB. Prospective evaluation of a clinical wound score to identify lower extremity wounds for comprehensive wound management. Undersea Hyperbaric Med. 2000; 27(Suppl): 34.
- Boyko EJ, Ahroni JH, Stensel V, et al. A prospective study of risk factors for diabetic foot ulcer, The Seattle Diabetic Foot Study. Diabetes Care. 1999; 22(7):1036-42.
- McNeely MJ, Boyko EJ, Ahroni JH, et al. The independent contributions of diabetic neuropathy and vasculopathy in foot ulceration, How great are the risks? Diabetes Care. 1995; 18(2):216-9.
- Boyko EJ, Ahroni JH, Cohen V, et al. Prediction of diabetic foot ulcer occurrence using commonly available clinical information: the Seattle Diabetic Foot Study. Diabetes Care. 2006; 29(6):1202-7.
- Abbott CA, Carrington AL, Ashe H, et al. North-West Diabetes Foot Care Study, The North-West Diabetes Foot Care Study: incidence of, and risk factors for, new diabetic foot ulceration in a community-based patient cohort. Diabet Med. 2002; 19(5):377-84.
- Nhan L, Strauss MB, Miller SS. Risk Factors for Diabetic Foot Ulcers: The First Step in Prevention. Consultant. 2013; 53(11):800-3.
- Nhan L, Strauss MB, Miller SS. Preventing Diabetic Foot Ulcers: A 4-Pronged Approach. Consultant. 2013; 53(12):865-72.