- Email: [email protected]
Off-loading the diabetic foot for ulcer prevention and healing
Off-loading the diabetic foot for ulcer prevention and healing Peter R. Cavanagh, PhD, DSc,a and Sicco A. Bus, PhD,b Seattle, Wash; and Amsterdam, The Netherlands Background: Retrospective and prospective studies have shown that elevated plantar pressure is a causative factor in the development of many plantar ulcers in diabetic patients and that ulceration is often a precursor of lower extremity amputation. In this article, we review the evidence that relieving areas of elevated plantar pressure (off-loading) can prevent and heal plantar ulceration. Results: There is no consensus in the literature concerning the role of off-loading through footwear in primary or secondary prevention of ulcers. This is likely due to the wide diversity of intervention and control conditions tested, the lack of information about off-loading efficacy of the footwear used, and the absence of a target pressure threshold for off-loading. Uncomplicated plantar ulcers should heal in 6 to 8 weeks with adequate off-loading. The total contact cast and other nonremovable devices are most effective because they eliminate the problem of nonadherence to recommendations for using a removable device. Conventional or standard therapeutic footwear is not effective in ulcer healing. Recent United States and European surveys show a large discrepancy between guidelines and clinical practice in off-loading diabetic foot ulcers. Many clinics continue to use methods that are known to be ineffective or have not been proven effective, while ignoring methods that have been demonstrated to be efficacious. Conclusions: A number of strategies are proposed to address this situation, notably the adoption and implementation of recently established international guidelines, which are evidence-based and specific, by professional societies in the United States and Europe. Such an approach would change the often poor current expectations for healing diabetic plantar ulcers. ( J Vasc Surg 2010;52:37S-43S.)
WHAT IS OFF-LOADING AND HOW CAN IT BE MEASURED? In the sensate foot, for example in a patient with rheumatoid arthritis, relieving the local pressure (off-loading) at painful regions of the foot is both driven and evaluated by the patient’s perceived pain.1 However, up to about 50% of people with diabetes mellitus (depending on ethnicity2) will eventually have loss of sensation in the feet secondary to peripheral neuropathy that is sufficient to allow them to injure the soft tissues of the plantar surface, a condition that has been termed loss of protective sensation.3 These areas need to be off-loaded, but because the patient has inadequate sensation, his or her feedback is not useful in judging whether or not pressure relief has been obtained.4 From the Department of Orthopaedics and Sports Medicine, University of Washington, Seattle;a and the Department of Rehabilitation, Academic Medical Center, Amsterdam.b Competition of interest: Peter R. Cavanagh holds equity in DIApedia LLC. He is an inventor on U.S. patents 6,610,897, 6,720,470, and 7,206,718, which elucidate a load-relieving dressing and a method of insole manufacture for off-loading. He has received honoraria from Merck, Eli Lilly, and ConvaTec and is the recipient of grants from the National Institutes of Health and NASA. This article is being co-published in the Journal of Vascular Surgery® and the Journal of the American Podiatric Medical Association. Correspondence: Peter R. Cavanagh, PhD, DSc, Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 981956500 (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a competition of interest. 0741-5214/$36.00 Copyright © 2010 by the Society for Vascular Surgery and the American Podiatric Medical Association. doi:10.1016/j.jvs.2010.06.007
The design of footwear and in-shoe devices to off-load at-risk areas of the diabetic foot has traditionally been considered to be an art rather than a science. This is despite the fact that a report of one of the first studies to actually measure the pressure relief from therapeutic footwear was published almost 50 years ago.5 Pressure measurement inside footwear is now more widespread, although because of economic and reimbursement issues, it is more common in a research setting than in clinical practice. An example of what the technique can demonstrate is shown in Fig 1. The substantial difference in off-loading, which can be seen between the two footwear conditions, is apparent, but the practitioner would not be able to determine this difference without the benefit of the measuring device. This is one of the reasons why off-loading the diabetic foot is so difficult and prone to failure. WHY IS OFF-LOADING NEEDED? Retrospective and prospective studies have shown that elevated plantar pressure is a cause of the development of plantar ulcers in diabetic patients6-8 and that ulceration is often a precursor of lower extremity amputation.9 Many structural abnormalities in the foot have been associated with increased levels of plantar pressure.10 In a person with diabetes, claw-toe deformity and Charcot neuroarthropathy are among the most important abnormalities that may cause significant disruption to the architecture of the foot11,12 and elevated local foot pressures.13,14 The combination of foot deformity, loss of protective sensation, and inadequate off-loading leads to tissue damage and ulceration. Once an ulcer has formed, studies described below indicate that unless the ulcerated area is off-loaded, healing may be chronically delayed, even in an adequately perfused 37S
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Fig 1. A, Peak plantar pressure distribution shown for the right foot during barefoot walking. The highest pressure experienced by each area of the foot through the support phase is shown on the diagram. The pressure distribution inside the shoe of the same patient is shown while (B) a flat cushioning insole and (C) a custom-made insole are being used. The red and purple colors represent the areas with the highest measured pressure. Note the superior off-loading of high-pressure regions identified during barefoot walking (C) in the custom insole compared with (B) the insole.
limb. After an ulcer is healed, the risk of recurrence is high— 40% in a median 4 months in one recent study15— showing the need for continuous off-loading in these patients. In this article, we will demonstrate that effective offloading of diabetic feet is important for ulcer healing and the prevention of ulcer recurrence. There is not yet sufficient evidence to support primary prevention of ulcers by off-loading, although clinical opinion strongly favors such an approach. Many new potential solutions for healing diabetic foot ulcers—such as topically applied growth factors, bioengineered skin, and stem cells— have been proposed. What all solutions have in common is that they require a mechanical environment that will not destroy the healing construct. This must be achieved by some device that will effectively remove mechanical stress from the wound and its immediate environment. The effectiveness of off-loading must be judged both by the relief of stress and by the patient’s adherence to the treatment. THE EVIDENCE BASE: WHAT WORKS AND WHAT DOES NOT WORK? Pressure off-loading. Total contact casts (TCCs) and removable walkers have been shown to be extremely effective in off-loading the diabetic foot, with reported peak pressure reduction in the forefoot up to 87% compared with a control condition (Fig 2).16-19 This effect may be achieved, among other mechanisms, by limiting ankle motion and redistributing load to the device itself.20 For these reasons, devices that only extend to the ankle, such as cast shoes and forefoot off-loading shoes, may be less effective in off-loading the foot than devices that extend above the ankle, as do TCCs and walkers. Reported off-loading values for such devices range from 44% to 64% compared with
control.18,19,21,22 Various therapeutic footwear designs can effectively off-load at-risk foot regions. Among these designs, rocker-bottom outsoles, custom-made insoles, and some shoe inserts (eg, metatarsal pads and medial arch supports) may reduce forefoot peak pressure between 16% and 52% compared with control.18,23-28 The design and placement of such devices is critical, however, and difficult to establish without pressure. The surgical approaches of Achilles tendon lengthening and liquid silicon injections under the metatarsal heads may only temporarily reduce pressure underneath the forefoot.29,30 Callus removal can reduce pressures by as much as 30%, although the durability of such relief is unknown.31,32 Different interventions exhibit a great variation in off-loading capacity (Fig 2), and this likely influences their efficacy in preventing or healing foot ulcers in diabetic patients. Ulcer healing. The largest evidence base on off-loading available is for the treatment of primarily uncomplicated neuropathic plantar foot ulcers (Fig 3). A number of different metrics are used in wound healing studies to characterize progress toward healing. These include percentage of wound closure in a given time and time to complete healing. It is generally assumed that time to complete healing is the most important consideration in clinical practice because this affects treatment costs and, presumably, lowers the risk for infection. Several randomized controlled trials (RCTs) have shown that the TCC is more effective than removable devices, both in healing proportions and time to healing.33-36 One recent RCT showed similar healing rates between the TCC and an ankle-high removable walker.37 A meta-analysis of 11 studies using the TCC33,34,38-46 showed that 92% of the 277 treated ulcers healed in a mean
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Fig 2. The off-loading capacity of different modalities used for the prevention and treatment of diabetic plantar foot ulcers is expressed as percentage of peak pressure reduction at the first metatarsal head region compared with a control condition. The lighter bars show the range in measured peak pressure reduction over different studies.
Fig 3. Histogram showing the proportion of healed ulcers expressed as a percentage (black bars) and time to healing expressed as a number of days (dark gray bars) for different off-loading modalities used to treat noncomplicated neuropathic plantar foot ulcers in diabetic patients. The light gray bars show the range found in different studies. The number of studies on which the bars showing percentage healing are based is also indicated.
duration of 42 days (range, 31-79 days; Ulbrecht JS, private communication). These ulcers had existed for an average of 282 days before treatment was initiated. Adverse effects with TCCs may occur, however, including reduced activity level, difficulty with sleeping or driving a car, and iatrogenic ulcers due to poor casting. Alternatively, below
the knee removable walkers that have been made nonremovable may be as effective as TCCs and more effective than standard removable walkers in healing plantar foot ulcers.47-49 Ulcer healing using removable devices is complicated by patients not adhering to recommendations for using
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their prescription device. One study found that patients used their prescribed removable device for an average of only 29% of their total daily number of steps.50 This may explain the lower effectiveness of removable devices and points to the importance of continued pressure relief to promote healing. Half-shoes, forefoot off-loading shoes, and cast shoes may be effective in healing neuropathic forefoot ulcers (healing proportions, 58%-91%), although their efficacy requires confirmation in prospective trials.34,51-54 Conventional or standard therapeutic footwear is not effective in ulcer healing, and the role of custom footwear in this context is not yet clear.55 Several prospective controlled studies have shown that surgical interventions such as Achilles tendon lengthening, metatarsal-phalangeal joint arthroplasty, and metatarsal head resection may have only limited additional value in ulcer healing compared with conservative treatment.56-60 Neuroischemic or infected wounds can also be treated with off-loading, although success rates are much lower than for purely neuropathic wounds.61 In summary, the data on ulcer healing support the use of nonremovable off-loading modalities, whereas the role of certain removable devices and surgical procedures requires further definition in prospective controlled studies. Ulcer prevention. Several prospective studies have shown a beneficial effect of the use of therapeutic footwear compared with standard footwear in preventing ulcer recurrence.62-65 However, one RCT showed no effect.66 These contrasting results are likely due to the wide diversity of intervention and control conditions tested and the lack of information about off-loading efficacy of the footwear used. This lack of standardization complicates the comparison of studies and limits the definition of the role of special footwear in ulcer prevention. In this context, a recent prospective 5-year analysis on the use of a previously defined footwear prescription algorithm67 showed much lower primary and secondary ulceration rates (21%) compared with the rates in the preceding 5 years in the same study center (70%). This demonstrates the usefulness of such a structured approach for ulcer prevention.68 Surgical interventions may reduce ulcer recurrence rates in selected patients compared with conservative treatment.56-59 However, complications with these procedures may occur, such as transfer ulcers and impaired balance during walking.69,70 Overall, the evidence base to support the safe use of therapeutic footwear and surgical procedures for ulcer prevention is still weak,71,72 although some recent studies show promising results in this regard. We do not yet know the exact pressure threshold that will prevent plantar tissue damage from occurring. Our group recently examined patients who had remained healed after plantar ulceration and found a mean pressure of approximately 200 kPa at the prior ulcer site.73 It may be that such a threshold is unique to each individual, but the 200 kPa value can serve as a goal for plantar off-loading until better evidence is available. Clinical recommendations. Efforts have recently been made by the International Working Group on the Diabetic
Foot to develop specific evidence-based guidelines on the use of footwear and off-loading for ulcer prevention and healing in the diabetic foot.72,74 Recommendations for the use of off-loading in treating noncomplicated neuropathic plantar foot ulcers are: ● ●
●
●
Relieving pressure on ulcers should always be a part of the treatment plan. TCCs and nonremovable walkers are the preferred interventions; however, the clinician should be aware of possible adverse effects of these devices. Forefoot off-loading shoes or cast shoes may be used when above the ankle devices are contraindicated or not tolerated by the patient. Conventional or standard therapeutic footwear should not be used since many other devices are more effective.
Recommendations for the use of off-loading in ulcer prevention in patients with an at-risk foot at-risk are: ● ● ●
Regular callus removal should be provided by a skilled health care professional. Patients should be urged to not walk barefoot at any time. Therapeutic footwear, including a custom-molded insole in a shoe with adequate depth, is the preferred intervention.
Although surgical procedures may be effective for ulcer healing or secondary prevention in selected patients, more studies are needed to better define the role of surgery compared with conservative treatment before it can be recommended for widespread use. DISCUSSION We have presented strong evidence that uncomplicated plantar ulcers can be healed in approximately 6 to 8 weeks. This time frame is in sharp contrast to reported clinical experience in the standard-of-care arms of U.S. clinical trials in which only 24% and 31% of uncomplicated ulcers were healed after 12 and 20 weeks, respectively.75 We believe that inadequate use of off-loading explains this difference. The guidelines discussed above are clear: nonremovable off-loading is the gold standard. But Wu et al76 found that 41% of 895 U.S. clinics responding to a survey attempted to off-load patients with shoes, whereas ⬍2% used TCCs. Similarly, Fife et al77 reported only 6% of ulcer patients received a TCC. However, among those patients who received it, the average cost of treatment was half as much as the cost incurred by patients who did not. In Europe, the situation is not markedly different. Prompers et al78 found that an average of only 35% (range 0%-68%) of plantar foot ulcers were treated with casting in 14 specialized centers across the continent. A large discrepancy exists between guidelines and clinical practice in off-loading diabetic foot ulcers. How can this gap between recommendations and practice be bridged? One solution would be for professional societies to help change the expectations among their
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members regarding the time that diabetic foot ulcers take to heal. Societies such as the American Podiatric Medical Association and the Society for Vascular Surgery could also formally adopt the international guidelines,74 which are presently not well known in the United States. Such lack of guidelines leads to heterogeneity of treatment that does not benefit the patient. Many providers resist guidelines because, as they correctly point out, every patient is unique and many additional intrinsic and extrinsic factors such as technical difficulty, time of application, cost-effectiveness, and reimbursement issues affect the choice of treatment. We believe that poor off-loading is poor treatment, regardless of the constellation of other factors that must be considered. Previous recommendations may have been too general, but recent evidence-based guidelines are specific and support implementation. In addition, in the same way that decubitus ulcers, hip fractures, and six other “reasonably preventable” conditions that occur after admission to the hospital are not reimbursed in the United States by Medicare, the future may bring a similar change in the burden of financial responsibility for what have traditionally been called “nonhealing” neuropathic ulcers. Many ulcers are indeed complicated by such factors as infection and vascular disease,79,80 and the same expectations for time to heal cannot be applied to infected neuroischemic wounds. But off-loading is still important in such complex wounds—perhaps even more important— because of the enhanced risk of limb loss in these patients. An additional barrier to appropriate prescription may be that some practitioners are not trained to specify appropriate footwear interventions and may resist referring patients to qualified specialists. Establishing a good relationship with qualified providers of therapeutic footwear and orthotic interventions is an important component of comprehensive care for the diabetic foot. If a provider does not have such expertise in-house, then locating a qualified individual, perhaps with the help of specialized societies (such as the Pedorthic Footwear Association in the United States, www.pedorthics.org), should be considered. Another major advance for off-loading the diabetic foot for ulcer prevention and healing would be a requirement that measurable and effective pressure reduction should result from all prescribed interventions and that preferably such pressure reduction be optimal (see Fig 1). Requirements for demonstrated efficacy have recently been introduced in Germany. This will not be possible at every treatment location because of cost, but specialized centers should consider adding the capability for pressure measurement to their prescription approach. Current clinical practice includes several modalities for healing diabetic foot ulcers that may be effective, although no evidence base for their use now exists. We strongly urge clinicians and researchers to prove the effectiveness of these devices to support their use in clinical practice. Documented pressure reduction is, of course, necessary— but not sufficient—for healing or preventing foot ulcers. Approaches that force adherence to off-loading in ulcer
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treatment by the application of some nonremovable device must be given consideration in all cases where there is no contraindication. Considerations for preventing ulcer recurrence are somewhat different, although no less important. Ulcer-free survival is poor,15 and a major challenge that needs to be faced is a reduction of the number of ulcer recurrences. Nonremovable devices cannot be used, and a behavioral intervention combined with footwear that effectively off-loads previously injured regions is required. Unfortunately, effective strategies to increase adherence have not yet been well established. The provider can increase the chance that the interventions will be used by providing attractive footwear and by accepting the fact that outdoor therapeutic shoes (the typical prescription) are unlikely to be worn at home. The provision of off-loading sandals or slippers may reduce barefoot walking at home, but currently it is likely the patient will have to bear the cost of the additional footwear. If future studies can show a reduction in reulceration when multiple types of footwear are dispensed, this would be a powerful rationale to petition for change in reimbursement policies. Currently, Medicare allows only one pair of shoes and three pairs of insoles per calendar year, and insurance companies in Europe generally do not reimburse multiple types of footwear in the same calendar year. CONCLUSION We have presented the evidence for the role of offloading in the prevention and treatment of plantar ulcers in the diabetic foot. We point out that there is a gap between evidence-based guidelines and current practice, particularly regarding the use of nonremovable off-loading devices to heal uncomplicated neuropathic ulcers. A number of strategies are proposed to address this gap, notably the adoption and implementation of recently established evidence-based and specific international guidelines by professional societies in the United States and Europe. Such an approach would change the current poor expectations for healing of diabetic plantar ulcers. REFERENCES 1. van der Leeden M, Steultjens MP, Terwee CB, Rosenbaum D, Turner D, Woodburn J, et al. A systematic review of instruments measuring foot function, foot pain, and foot-related disability in patients with rheumatoid arthritis. Arthritis Rheum 2008;59:1257-69. 2. Sosenko JM. The prevalence of diabetic neuropathy according to ethnicity. Curr Diab Rep 2009;9:435-9. 3. Armstrong DG. Loss of protective sensation: a practical evidence-based definition. J Foot Ankle Surg 1999;38:79-80. 4. Wu SC, Crews RT, Armstrong DG. The pivotal role of offloading in the management of neuropathic foot ulceration. Curr Diab Rep 2005;5: 423-9. 5. Bauman JH, Girling JP, Brand PW. Plantar pressures and trophic ulceration: an evaluation of footwear. J Bone Joint Surg Br 1963;45: 652-73. 6. Veves A, Murray HJ, Young MJ, Boulton AJ. The risk of foot ulceration in diabetic patients with high foot pressure: a prospective study. Diabetologia 1992;35:660-3. 7. Pham H, Armstrong DA, Harvey C, Harkless LB, Giurini JM, Veves A. Screening techniques to identify people at high risk for diabetic foot ulceration. Diabetes Care 2000;23:606-11.
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8. Frykberg RG, Lavery LA, Pham H, Harvey C, Harkless L, Veves A. Role of neuropathy and high foot pressures in diabetic foot ulceration. Diabetes Care 1998;21:1714-9. 9. Pecoraro RE, Reiber GE, Burgess EM. Pathways to diabetic limb amputation. Basis for prevention. Diabetes Care 1990;13:513-21. 10. Bus SA. Foot structure and footwear prescription in diabetes mellitus. Diabetes Metab Res Rev 2008;24(Suppl 1):S90-5. 11. Bus SA, Maas M, Cavanagh PR, Michels RPJ, Levi M. Plantar fat-pad displacement in neuropathic diabetic patients with toe deformity: a magnetic resonance imaging study. Diabetes Care 2004;27:2376-81. 12. van der Ven, V, Chapman CB, Bowker JH. Charcot neuroarthropathy of the foot and ankle. J Am Acad Orthop Surg 2009;17:562-71. 13. Bus SA, Maas M, de Lange LA, Michels RP, Levi M. Elevated plantar pressures in neuropathic diabetic patients with claw/hammer toe deformity. J Biomech 2005;38:1918-25. 14. Armstrong DG, Lavery LA. Elevated peak plantar pressures in patients who have Charcot arthropathy. J Bone Joint Surg Am 1998;80:365-9. 15. Pound N, Chipchase S, Treece K, Game F, Jeffcoate W. Ulcer-free survival following management of foot ulcers in diabetes. Diabet Med 2005;22:1306-9. 16. Lavery LA, Vela SA, Fleischli JG, Armstrong DG, Lavery DC. Reducing plantar pressure in the neuropathic foot. A comparison of footwear. Diabetes Care 1997;20:1706-10. 17. Fleischli JG, Lavery LA, Vela SA, Ashry H, Lavery DC. Comparison of strategies for reducing pressure at the site of neuropathic ulcers. J Am Podiatr Med Assoc 1997;87:466-72. 18. Beuker BJ, van Deursen RW, Price P, Manning EA, van Baal JG, Harding KG. Plantar pressure in off-loading devices used in diabetic ulcer treatment. Wound Repair Regen 2005;13:537-42. 19. Nagel A, Rosenbaum D. Vacuum cushioned removable cast walkers reduce foot loading in patients with diabetes mellitus. Gait Posture 2009;30:11-5. 20. Shaw JE, Hsi WL, Ulbrecht JS, Norkitis A, Becker MB, Cavanagh PR. The mechanism of plantar unloading in total contact casts: implications for design and clinical use. Foot Ankle Int 1997;18:809-17. 21. Bus SA, Waaijman R, Arts M, Manning H. The efficacy of a removable vacuum-cushioned cast replacement system in reducing plantar forefoot pressures in diabetic patients. Clin Biomech (Bristol, Avon) 2009;24: 459-64. 22. Bus SA, van Deursen RW, Kanade RV, Wissink M, Manning EA, van Baal JG, et al. Plantar pressure relief in the diabetic foot using forefoot offloading shoes. Gait Posture 2009;29:618-22. 23. Bus SA, Ulbrecht JS, Cavanagh PR. Pressure relief and load redistribution by custom-made insoles in diabetic patients with neuropathy and foot deformity. Clin Biomech 2004;19:629-38. 24. Guldemond NA, Leffers P, Schaper NC, Sanders AP, Nieman F, Willems P, et al. The effects of insole configurations on forefoot plantar pressure and walking convenience in diabetic patients with neuropathic feet. Clin Biomech 2007;22:81-7. 25. Praet SF, Louwerens JW. The influence of shoe design on plantar pressures in neuropathic feet. Diabetes Care 2003;26:441-5. 26. van Schie C, Ulbrecht JS, Becker MB, Cavanagh PR. Design criteria for rigid rocker shoes. Foot Ankle Int 2000;21:833-44. 27. Schaff PS, Cavanagh PR. Shoes for the insensitive foot: the effect of a “rocker bottom” shoe modification on plantar pressure distribution. Foot Ankle 1990;11:129-40. 28. Lord M, Hosein R. Pressure redistribution by molded inserts in diabetic footwear: a pilot study. J Rehabil Res Dev 1994;31:214-21. 29. van Schie CH, Whalley A, Armstrong DG, Vileikyte L, Boulton AJ. The effect of silicone injections in the diabetic foot on peak plantar pressure and plantar tissue thickness: a 2-year follow-up. Arch Phys Med Rehabil 2002;83:919-23. 30. Maluf KS, Mueller MJ, Strube MJ, Engsberg JR, Johnson JE. Tendon Achilles lengthening for the treatment of neuropathic ulcers causes a temporary reduction in forefoot pressure associated with changes in plantar flexor power rather than ankle motion during gait. J Biomech 2004;37:897-906. 31. Pitei DL, Foster A, Edmonds M. The effect of regular callus removal on foot pressures. J Foot Ankle Surg 1999;38:251-5.
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32. Young MJ, Cavanagh PR, Thomas G, Johnson MM, Murray H, Boulton AJ. The effect of callus removal on dynamic plantar foot pressures in diabetic patients. Diabet Med 1992;9:55-7. 33. Mueller MJ, Diamond JE, Sinacore DR, Delitto A, Blair VP 3rd, Drury DA, et al. Total contact casting in treatment of diabetic plantar ulcers. Controlled clinical trial. Diabetes Care 1989;12:384-8. 34. Armstrong DG, Nguyen HC, Lavery LA, van Schie CH, Boulton AJ, Harkless LB. Off-loading the diabetic foot wound: a randomized clinical trial. Diabetes Care 2001;24:1019-22. 35. Caravaggi C, Faglia E, De Giglio R, Mantero M, Quarantiello A, Sommariva E, et al. Effectiveness and safety of a nonremovable fiberglass off-bearing cast versus a therapeutic shoe in the treatment of neuropathic foot ulcers: a randomized study. Diabetes Care 2000;23: 1746-51. 36. Ha VG, Siney H, Hartmann-Heurtier A, Jacqueminet S, Greau F, Grimaldi A. Nonremovable, windowed, fiberglass cast boot in the treatment of diabetic plantar ulcers: efficacy, safety, and compliance. Diabetes Care 2003;26:2848-52. 37. Ezio F, Carlo C, Giacomo C, Adriana S, Vincenzo C, Vanda V, et al. Effectiveness of removable waler cast versus non-removable fiberglass off-bearing cast in the healing of diabetic plantar foot ulcer- a randomized controlled trial. Diabetes Care 2010 [E-pub: doi: 10.2337/dc091708]. 38. Diamond JE, Mueller MJ, Delitto A. Effect of total contact cast immobilization on subtalar and talocrural joint motion in patients with diabetes mellitus. Phys Ther 1993;73:310-5. 39. Baker RE. Total contact casting. J Am Podiatr Med Assoc 1995;85: 172-6. 40. Armstrong DG, Lavery LA, Bushman TR. Peak foot pressures influence the healing time of diabetic foot ulcers treated with total contact casts. J Rehabil Res Dev 1998;35:1-5. 41. Lin SS, Lee TH, Wapner KL. Plantar forefoot ulceration with equinus deformity of the ankle in diabetic patients: the effect of tendo-Achilles lengthening and total contact casting. Orthopedics 1996;19:465-75. 42. Boulton AJ, Bowker JH, Gadia M, Lemerman R, Caswell K, Skyler JS, et al. Use of plaster casts in the management of diabetic neuropathic foot ulcers. Diabetes Care 1986;9:149-52. 43. Walker SC, Helm PA, Pullium G. Total contact casting and chronic diabetic neuropathic foot ulcerations: healing rates by wound location. Arch Phys Med Rehabil 1987;68:217-21. 44. Sinacore DR, Mueller MJ, Diamond JE, Blair VP, III, Drury D, Rose SJ. Diabetic plantar ulcers treated by total contact casting. A clinical report. Phys Ther 1987;67:1543-9. 45. Laing PW, Cogley DI, Klenerman L. Neuropathic foot ulceration treated by total contact casts. J Bone Joint Surg Br 1992;74:133-6. 46. Birke JA, Novick A, Graham SL, Coleman WC, Brasseaux DM. Methods of treating plantar ulcers. Phys Ther 1991;71:116-22. 47. Piaggesi A, Macchiarini S, Rizzo L, Palumbo F, Tedeschi A, Nobili LA, et al. An off-the-shelf instant contact casting device for the management of diabetic foot ulcers: a randomized prospective trial versus traditional fiberglass cast. Diabetes Care 2007;30:586-90. 48. Katz IA, Harlan A, Miranda-Palma B, Prieto-Sanchez L, Armstrong DG, Bowker JH, et al. A randomized trial of two irremovable offloading devices in the management of plantar neuropathic diabetic foot ulcers. Diabetes Care 2005;28:555-9. 49. Armstrong DG, Lavery LA, Wu S, Boulton AJ. Evaluation of removable and irremovable cast walkers in the healing of diabetic foot wounds: a randomized controlled trial. Diabetes Care 2005;28:551-4. 50. Armstrong DG, Lavery LA, Kimbriel HR, Nixon BP, Boulton AJ. Activity patterns of patients with diabetic foot ulceration: patients with active ulceration may not adhere to a standard pressure off-loading regimen. Diabetes Care 2003;26:2595-7. 51. Hissink RJ, Manning HA, van Baal JG. The MABAL shoe, an alternative method in contact casting for the treatment of neuropathic diabetic foot ulcers. Foot Ankle Int 2000;21:320-3. 52. Chantelau E, Breuer U, Leisch AC, Tanudjaja T, Reuter M. Outpatient treatment of unilateral diabetic foot ulcers with ‘half shoes.’ Diabet Med 1993;10:267-70.
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53. Knowles EA, Armstrong DG, Hayat SA, Khawaja KI, Malik RA, Boulton AJ. Offloading diabetic foot wounds using the scotchcast boot: a retrospective study. Ostomy Wound Manage 2002;48:50-3. 54. Dumont IJ, Lepeut MS, Tsirtsikolou DM, Popielarz SM, Cordonnier MM, Fayard AJ, et al. A proof-of-concept study of the effectiveness of a removable device for offloading in patients with neuropathic ulceration of the foot: the Ransart boot. Diabet Med 2009;26:778-82. 55. Van De Weg FB, Van Der Windt DA, Vahl AC. Wound healing: total contact cast vs. custom-made temporary footwear for patients with diabetic foot ulceration. Prosthet Orthot Int 2008;32:3-11. 56. Mueller MJ, Sinacore DR, Hastings MK, Strube MJ, Johnson JE. Effect of Achilles tendon lengthening on neuropathic plantar ulcers. A randomized clinical trial. J Bone Joint Surg Am 2003;85:1436-45. 57. Piaggesi A, Schipani E, Campi F, Romanelli M, Baccetti F, Arvia C, et al. Conservative surgical approach versus non-surgical management for diabetic neuropathic foot ulcers: a randomized trial. Diabet Med 1998; 15:412-7. 58. Armstrong DG, Rosales MA, Gashi A. Efficacy of fifth metatarsal head resection for treatment of chronic diabetic foot ulceration. J Am Podiatr Med Assoc 2005;95:353-6. 59. Armstrong DG, Lavery LA, Vazquez JR, Short B, Kimbriel HR, Nixon BP, et al. Clinical efficacy of the first metatarsophalangeal joint arthroplasty as a curative procedure for hallux interphalangeal joint wounds in patients with diabetes. Diabetes Care 2003;26:3284-328. 60. Lin SS, Bono CM, Lee TH. Total contact casting and Keller arthoplasty for diabetic great toe ulceration under the interphalangeal joint. Foot Ankle Int 2000;21:588-93. 61. Nabuurs-Franssen MH, Sleegers R, Huijberts MS, Wijnen W, Sanders AP, Walenkamp G, et al. Total contact casting of the diabetic foot in daily practice: a prospective follow-up study. Diabetes Care 2005;28:243-7. 62. Uccioli L, Faglia E, Monticone G, Favales F, Durola L, Aldeghi A, et al. Manufactured shoes in the prevention of diabetic foot ulcers. Diabetes Care 1995;18:1376-8. 63. Litzelman DK, Marriott DJ, Vinicor F. The role of footwear in the prevention of foot lesions in patients with NIDDM. Conventional wisdom or evidence-based practice? Diabetes Care 1997;20:156-62. 64. Dargis V, Pantelejeva O, Jonushaite A, Vileikyte L, Boulton AJ. Benefits of a multidisciplinary approach in the management of recurrent diabetic foot ulceration in Lithuania: a prospective study. Diabetes Care 1999; 22:1428-31. 65. Viswanathan V, Madhavan S, Gnanasundaram S, Gopalakrishna G, Das BN, Rajasekar S, et al. Effectiveness of different types of footwear insoles for the diabetic neuropathic foot: a follow-up study. Diabetes Care 2004;27:474-7. 66. Reiber GE, Smith DG, Wallace C, Sullivan K, Hayes S, Vath C, et al. Effect of therapeutic footwear on foot reulceration in patients with diabetes: a randomized controlled trial. JAMA 2002;287:2552-8.
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67. Dahmen R, Haspels R, Koomen B, Hoeksma AF. Therapeutic footwear for the neuropathic foot: an algorithm. Diabetes Care 2001;24:705-9. 68. Rizzo L, Teobaldi I, Fallani E, Tedeschi A, Leporati E, Scirè V, et al. A structured follow-up reduces the incidence of recurrences in high risk diabetic foot patients: a prospective study (Abstract O-26). 8th Scientific Meeting of the Diabetic Foot Study Group, Pisa, Italy, September 11-14, 2008. 69. Mueller MJ, Sinacore DR, Hastings MK, Lott DJ, Strube MJ, Johnson JE. Impact of achilles tendon lengthening on functional limitations and perceived disability in people with a neuropathic plantar ulcer. Diabetes Care 2004;27:1559-64. 70. Salsich GB, Mueller MJ, Hastings MK, Sinacore DR, Strube MJ, Johnson JE. Effect of Achilles tendon lengthening on ankle muscle performance in people with diabetes mellitus and a neuropathic plantar ulcer. Phys Ther 2005;85:34-43. 71. Maciejewski ML, Reiber GE, Smith DG, Wallace C, Hayes S, Boyko EJ. Effectiveness of diabetic therapeutic footwear in preventing reulceration. Diabetes Care 2004;27:1774-82. 72. Bus SA, Valk GD, van Deursen RW, Armstrong DG, Caravaggi C, Hlavacek P, et al. The effectiveness of footwear and offloading interventions to prevent and heal foot ulcers and reduce plantar pressure in diabetes: a systematic review. Diabetes Metab Res Rev 2008;24(Suppl 1):S162-80. 73. Owings TM, Apelqvist J, Stenstrom A, Becker M, Bus SA, Kalpen A, et al. Plantar pressures in diabetic patients with foot ulcers which have remained healed. Diabet Med 2009;26:1141-6. 74. International Working Group on the Diabetic Foot. International Consensus on the Diabetic Foot and Practical Guidelines on the Management and Prevention of the Diabetic Foot. 2007. Amsterdam, The Netherlands, on DVD (www.idf.org/bookshop). 75. Margolis DJ, Kantor J, Berlin JA. Healing of diabetic neuropathic foot ulcers receiving standard treatment. A meta-analysis. Diabetes Care 1999;22:692-5. 76. Wu SC, Jensen JL, Weber AK, Robinson DE, Armstrong DG. Use of pressure offloading devices in diabetic foot ulcers: do we practice what we preach? Diabetes Care 2008;31:2118-9. 77. Fife CE, Carter MJ, Walker D. Why is it so hard to do the right thing in wound care? Wound Repair Regen 2010;18:154-8. 78. Prompers L, Huijberts M, Apelqvist J, Jude E, Piaggesi A, Bakker K, et al. Delivery of care to diabetic patients with foot ulcers in daily practice: results of the Eurodiale Study, a prospective cohort study. Diabet Med 2008;25:700-7. 79. Cavanagh PR, Lipsky BA, Bradbury AW, Botek G. Treatment for diabetic foot ulcers. Lancet 2005;366:1725-35. 80. Hinchliffe RJ, Valk GD, Apelqvist J, Armstrong DG, Bakker K, Game FL, et al. A systematic review of the effectiveness of interventions to enhance the healing of chronic ulcers of the foot in diabetes. Diabetes Metab Res Rev 2008;24(Suppl 1):S119-4.
WHAT IS OFF-LOADING AND HOW CAN IT BE MEASURED? In the sensate foot, for example in a patient with rheumatoid arthritis, relieving the local pressure (off-loading) at painful regions of the foot is both driven and evaluated by the patient’s perceived pain.1 However, up to about 50% of people with diabetes mellitus (depending on ethnicity2) will eventually have loss of sensation in the feet secondary to peripheral neuropathy that is sufficient to allow them to injure the soft tissues of the plantar surface, a condition that has been termed loss of protective sensation.3 These areas need to be off-loaded, but because the patient has inadequate sensation, his or her feedback is not useful in judging whether or not pressure relief has been obtained.4 From the Department of Orthopaedics and Sports Medicine, University of Washington, Seattle;a and the Department of Rehabilitation, Academic Medical Center, Amsterdam.b Competition of interest: Peter R. Cavanagh holds equity in DIApedia LLC. He is an inventor on U.S. patents 6,610,897, 6,720,470, and 7,206,718, which elucidate a load-relieving dressing and a method of insole manufacture for off-loading. He has received honoraria from Merck, Eli Lilly, and ConvaTec and is the recipient of grants from the National Institutes of Health and NASA. This article is being co-published in the Journal of Vascular Surgery® and the Journal of the American Podiatric Medical Association. Correspondence: Peter R. Cavanagh, PhD, DSc, Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 981956500 (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a competition of interest. 0741-5214/$36.00 Copyright © 2010 by the Society for Vascular Surgery and the American Podiatric Medical Association. doi:10.1016/j.jvs.2010.06.007
The design of footwear and in-shoe devices to off-load at-risk areas of the diabetic foot has traditionally been considered to be an art rather than a science. This is despite the fact that a report of one of the first studies to actually measure the pressure relief from therapeutic footwear was published almost 50 years ago.5 Pressure measurement inside footwear is now more widespread, although because of economic and reimbursement issues, it is more common in a research setting than in clinical practice. An example of what the technique can demonstrate is shown in Fig 1. The substantial difference in off-loading, which can be seen between the two footwear conditions, is apparent, but the practitioner would not be able to determine this difference without the benefit of the measuring device. This is one of the reasons why off-loading the diabetic foot is so difficult and prone to failure. WHY IS OFF-LOADING NEEDED? Retrospective and prospective studies have shown that elevated plantar pressure is a cause of the development of plantar ulcers in diabetic patients6-8 and that ulceration is often a precursor of lower extremity amputation.9 Many structural abnormalities in the foot have been associated with increased levels of plantar pressure.10 In a person with diabetes, claw-toe deformity and Charcot neuroarthropathy are among the most important abnormalities that may cause significant disruption to the architecture of the foot11,12 and elevated local foot pressures.13,14 The combination of foot deformity, loss of protective sensation, and inadequate off-loading leads to tissue damage and ulceration. Once an ulcer has formed, studies described below indicate that unless the ulcerated area is off-loaded, healing may be chronically delayed, even in an adequately perfused 37S
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Fig 1. A, Peak plantar pressure distribution shown for the right foot during barefoot walking. The highest pressure experienced by each area of the foot through the support phase is shown on the diagram. The pressure distribution inside the shoe of the same patient is shown while (B) a flat cushioning insole and (C) a custom-made insole are being used. The red and purple colors represent the areas with the highest measured pressure. Note the superior off-loading of high-pressure regions identified during barefoot walking (C) in the custom insole compared with (B) the insole.
limb. After an ulcer is healed, the risk of recurrence is high— 40% in a median 4 months in one recent study15— showing the need for continuous off-loading in these patients. In this article, we will demonstrate that effective offloading of diabetic feet is important for ulcer healing and the prevention of ulcer recurrence. There is not yet sufficient evidence to support primary prevention of ulcers by off-loading, although clinical opinion strongly favors such an approach. Many new potential solutions for healing diabetic foot ulcers—such as topically applied growth factors, bioengineered skin, and stem cells— have been proposed. What all solutions have in common is that they require a mechanical environment that will not destroy the healing construct. This must be achieved by some device that will effectively remove mechanical stress from the wound and its immediate environment. The effectiveness of off-loading must be judged both by the relief of stress and by the patient’s adherence to the treatment. THE EVIDENCE BASE: WHAT WORKS AND WHAT DOES NOT WORK? Pressure off-loading. Total contact casts (TCCs) and removable walkers have been shown to be extremely effective in off-loading the diabetic foot, with reported peak pressure reduction in the forefoot up to 87% compared with a control condition (Fig 2).16-19 This effect may be achieved, among other mechanisms, by limiting ankle motion and redistributing load to the device itself.20 For these reasons, devices that only extend to the ankle, such as cast shoes and forefoot off-loading shoes, may be less effective in off-loading the foot than devices that extend above the ankle, as do TCCs and walkers. Reported off-loading values for such devices range from 44% to 64% compared with
control.18,19,21,22 Various therapeutic footwear designs can effectively off-load at-risk foot regions. Among these designs, rocker-bottom outsoles, custom-made insoles, and some shoe inserts (eg, metatarsal pads and medial arch supports) may reduce forefoot peak pressure between 16% and 52% compared with control.18,23-28 The design and placement of such devices is critical, however, and difficult to establish without pressure. The surgical approaches of Achilles tendon lengthening and liquid silicon injections under the metatarsal heads may only temporarily reduce pressure underneath the forefoot.29,30 Callus removal can reduce pressures by as much as 30%, although the durability of such relief is unknown.31,32 Different interventions exhibit a great variation in off-loading capacity (Fig 2), and this likely influences their efficacy in preventing or healing foot ulcers in diabetic patients. Ulcer healing. The largest evidence base on off-loading available is for the treatment of primarily uncomplicated neuropathic plantar foot ulcers (Fig 3). A number of different metrics are used in wound healing studies to characterize progress toward healing. These include percentage of wound closure in a given time and time to complete healing. It is generally assumed that time to complete healing is the most important consideration in clinical practice because this affects treatment costs and, presumably, lowers the risk for infection. Several randomized controlled trials (RCTs) have shown that the TCC is more effective than removable devices, both in healing proportions and time to healing.33-36 One recent RCT showed similar healing rates between the TCC and an ankle-high removable walker.37 A meta-analysis of 11 studies using the TCC33,34,38-46 showed that 92% of the 277 treated ulcers healed in a mean
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Fig 2. The off-loading capacity of different modalities used for the prevention and treatment of diabetic plantar foot ulcers is expressed as percentage of peak pressure reduction at the first metatarsal head region compared with a control condition. The lighter bars show the range in measured peak pressure reduction over different studies.
Fig 3. Histogram showing the proportion of healed ulcers expressed as a percentage (black bars) and time to healing expressed as a number of days (dark gray bars) for different off-loading modalities used to treat noncomplicated neuropathic plantar foot ulcers in diabetic patients. The light gray bars show the range found in different studies. The number of studies on which the bars showing percentage healing are based is also indicated.
duration of 42 days (range, 31-79 days; Ulbrecht JS, private communication). These ulcers had existed for an average of 282 days before treatment was initiated. Adverse effects with TCCs may occur, however, including reduced activity level, difficulty with sleeping or driving a car, and iatrogenic ulcers due to poor casting. Alternatively, below
the knee removable walkers that have been made nonremovable may be as effective as TCCs and more effective than standard removable walkers in healing plantar foot ulcers.47-49 Ulcer healing using removable devices is complicated by patients not adhering to recommendations for using
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their prescription device. One study found that patients used their prescribed removable device for an average of only 29% of their total daily number of steps.50 This may explain the lower effectiveness of removable devices and points to the importance of continued pressure relief to promote healing. Half-shoes, forefoot off-loading shoes, and cast shoes may be effective in healing neuropathic forefoot ulcers (healing proportions, 58%-91%), although their efficacy requires confirmation in prospective trials.34,51-54 Conventional or standard therapeutic footwear is not effective in ulcer healing, and the role of custom footwear in this context is not yet clear.55 Several prospective controlled studies have shown that surgical interventions such as Achilles tendon lengthening, metatarsal-phalangeal joint arthroplasty, and metatarsal head resection may have only limited additional value in ulcer healing compared with conservative treatment.56-60 Neuroischemic or infected wounds can also be treated with off-loading, although success rates are much lower than for purely neuropathic wounds.61 In summary, the data on ulcer healing support the use of nonremovable off-loading modalities, whereas the role of certain removable devices and surgical procedures requires further definition in prospective controlled studies. Ulcer prevention. Several prospective studies have shown a beneficial effect of the use of therapeutic footwear compared with standard footwear in preventing ulcer recurrence.62-65 However, one RCT showed no effect.66 These contrasting results are likely due to the wide diversity of intervention and control conditions tested and the lack of information about off-loading efficacy of the footwear used. This lack of standardization complicates the comparison of studies and limits the definition of the role of special footwear in ulcer prevention. In this context, a recent prospective 5-year analysis on the use of a previously defined footwear prescription algorithm67 showed much lower primary and secondary ulceration rates (21%) compared with the rates in the preceding 5 years in the same study center (70%). This demonstrates the usefulness of such a structured approach for ulcer prevention.68 Surgical interventions may reduce ulcer recurrence rates in selected patients compared with conservative treatment.56-59 However, complications with these procedures may occur, such as transfer ulcers and impaired balance during walking.69,70 Overall, the evidence base to support the safe use of therapeutic footwear and surgical procedures for ulcer prevention is still weak,71,72 although some recent studies show promising results in this regard. We do not yet know the exact pressure threshold that will prevent plantar tissue damage from occurring. Our group recently examined patients who had remained healed after plantar ulceration and found a mean pressure of approximately 200 kPa at the prior ulcer site.73 It may be that such a threshold is unique to each individual, but the 200 kPa value can serve as a goal for plantar off-loading until better evidence is available. Clinical recommendations. Efforts have recently been made by the International Working Group on the Diabetic
Foot to develop specific evidence-based guidelines on the use of footwear and off-loading for ulcer prevention and healing in the diabetic foot.72,74 Recommendations for the use of off-loading in treating noncomplicated neuropathic plantar foot ulcers are: ● ●
●
●
Relieving pressure on ulcers should always be a part of the treatment plan. TCCs and nonremovable walkers are the preferred interventions; however, the clinician should be aware of possible adverse effects of these devices. Forefoot off-loading shoes or cast shoes may be used when above the ankle devices are contraindicated or not tolerated by the patient. Conventional or standard therapeutic footwear should not be used since many other devices are more effective.
Recommendations for the use of off-loading in ulcer prevention in patients with an at-risk foot at-risk are: ● ● ●
Regular callus removal should be provided by a skilled health care professional. Patients should be urged to not walk barefoot at any time. Therapeutic footwear, including a custom-molded insole in a shoe with adequate depth, is the preferred intervention.
Although surgical procedures may be effective for ulcer healing or secondary prevention in selected patients, more studies are needed to better define the role of surgery compared with conservative treatment before it can be recommended for widespread use. DISCUSSION We have presented strong evidence that uncomplicated plantar ulcers can be healed in approximately 6 to 8 weeks. This time frame is in sharp contrast to reported clinical experience in the standard-of-care arms of U.S. clinical trials in which only 24% and 31% of uncomplicated ulcers were healed after 12 and 20 weeks, respectively.75 We believe that inadequate use of off-loading explains this difference. The guidelines discussed above are clear: nonremovable off-loading is the gold standard. But Wu et al76 found that 41% of 895 U.S. clinics responding to a survey attempted to off-load patients with shoes, whereas ⬍2% used TCCs. Similarly, Fife et al77 reported only 6% of ulcer patients received a TCC. However, among those patients who received it, the average cost of treatment was half as much as the cost incurred by patients who did not. In Europe, the situation is not markedly different. Prompers et al78 found that an average of only 35% (range 0%-68%) of plantar foot ulcers were treated with casting in 14 specialized centers across the continent. A large discrepancy exists between guidelines and clinical practice in off-loading diabetic foot ulcers. How can this gap between recommendations and practice be bridged? One solution would be for professional societies to help change the expectations among their
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members regarding the time that diabetic foot ulcers take to heal. Societies such as the American Podiatric Medical Association and the Society for Vascular Surgery could also formally adopt the international guidelines,74 which are presently not well known in the United States. Such lack of guidelines leads to heterogeneity of treatment that does not benefit the patient. Many providers resist guidelines because, as they correctly point out, every patient is unique and many additional intrinsic and extrinsic factors such as technical difficulty, time of application, cost-effectiveness, and reimbursement issues affect the choice of treatment. We believe that poor off-loading is poor treatment, regardless of the constellation of other factors that must be considered. Previous recommendations may have been too general, but recent evidence-based guidelines are specific and support implementation. In addition, in the same way that decubitus ulcers, hip fractures, and six other “reasonably preventable” conditions that occur after admission to the hospital are not reimbursed in the United States by Medicare, the future may bring a similar change in the burden of financial responsibility for what have traditionally been called “nonhealing” neuropathic ulcers. Many ulcers are indeed complicated by such factors as infection and vascular disease,79,80 and the same expectations for time to heal cannot be applied to infected neuroischemic wounds. But off-loading is still important in such complex wounds—perhaps even more important— because of the enhanced risk of limb loss in these patients. An additional barrier to appropriate prescription may be that some practitioners are not trained to specify appropriate footwear interventions and may resist referring patients to qualified specialists. Establishing a good relationship with qualified providers of therapeutic footwear and orthotic interventions is an important component of comprehensive care for the diabetic foot. If a provider does not have such expertise in-house, then locating a qualified individual, perhaps with the help of specialized societies (such as the Pedorthic Footwear Association in the United States, www.pedorthics.org), should be considered. Another major advance for off-loading the diabetic foot for ulcer prevention and healing would be a requirement that measurable and effective pressure reduction should result from all prescribed interventions and that preferably such pressure reduction be optimal (see Fig 1). Requirements for demonstrated efficacy have recently been introduced in Germany. This will not be possible at every treatment location because of cost, but specialized centers should consider adding the capability for pressure measurement to their prescription approach. Current clinical practice includes several modalities for healing diabetic foot ulcers that may be effective, although no evidence base for their use now exists. We strongly urge clinicians and researchers to prove the effectiveness of these devices to support their use in clinical practice. Documented pressure reduction is, of course, necessary— but not sufficient—for healing or preventing foot ulcers. Approaches that force adherence to off-loading in ulcer
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treatment by the application of some nonremovable device must be given consideration in all cases where there is no contraindication. Considerations for preventing ulcer recurrence are somewhat different, although no less important. Ulcer-free survival is poor,15 and a major challenge that needs to be faced is a reduction of the number of ulcer recurrences. Nonremovable devices cannot be used, and a behavioral intervention combined with footwear that effectively off-loads previously injured regions is required. Unfortunately, effective strategies to increase adherence have not yet been well established. The provider can increase the chance that the interventions will be used by providing attractive footwear and by accepting the fact that outdoor therapeutic shoes (the typical prescription) are unlikely to be worn at home. The provision of off-loading sandals or slippers may reduce barefoot walking at home, but currently it is likely the patient will have to bear the cost of the additional footwear. If future studies can show a reduction in reulceration when multiple types of footwear are dispensed, this would be a powerful rationale to petition for change in reimbursement policies. Currently, Medicare allows only one pair of shoes and three pairs of insoles per calendar year, and insurance companies in Europe generally do not reimburse multiple types of footwear in the same calendar year. CONCLUSION We have presented the evidence for the role of offloading in the prevention and treatment of plantar ulcers in the diabetic foot. We point out that there is a gap between evidence-based guidelines and current practice, particularly regarding the use of nonremovable off-loading devices to heal uncomplicated neuropathic ulcers. A number of strategies are proposed to address this gap, notably the adoption and implementation of recently established evidence-based and specific international guidelines by professional societies in the United States and Europe. Such an approach would change the current poor expectations for healing of diabetic plantar ulcers. REFERENCES 1. van der Leeden M, Steultjens MP, Terwee CB, Rosenbaum D, Turner D, Woodburn J, et al. A systematic review of instruments measuring foot function, foot pain, and foot-related disability in patients with rheumatoid arthritis. Arthritis Rheum 2008;59:1257-69. 2. Sosenko JM. The prevalence of diabetic neuropathy according to ethnicity. Curr Diab Rep 2009;9:435-9. 3. Armstrong DG. Loss of protective sensation: a practical evidence-based definition. J Foot Ankle Surg 1999;38:79-80. 4. Wu SC, Crews RT, Armstrong DG. The pivotal role of offloading in the management of neuropathic foot ulceration. Curr Diab Rep 2005;5: 423-9. 5. Bauman JH, Girling JP, Brand PW. Plantar pressures and trophic ulceration: an evaluation of footwear. J Bone Joint Surg Br 1963;45: 652-73. 6. Veves A, Murray HJ, Young MJ, Boulton AJ. The risk of foot ulceration in diabetic patients with high foot pressure: a prospective study. Diabetologia 1992;35:660-3. 7. Pham H, Armstrong DA, Harvey C, Harkless LB, Giurini JM, Veves A. Screening techniques to identify people at high risk for diabetic foot ulceration. Diabetes Care 2000;23:606-11.
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8. Frykberg RG, Lavery LA, Pham H, Harvey C, Harkless L, Veves A. Role of neuropathy and high foot pressures in diabetic foot ulceration. Diabetes Care 1998;21:1714-9. 9. Pecoraro RE, Reiber GE, Burgess EM. Pathways to diabetic limb amputation. Basis for prevention. Diabetes Care 1990;13:513-21. 10. Bus SA. Foot structure and footwear prescription in diabetes mellitus. Diabetes Metab Res Rev 2008;24(Suppl 1):S90-5. 11. Bus SA, Maas M, Cavanagh PR, Michels RPJ, Levi M. Plantar fat-pad displacement in neuropathic diabetic patients with toe deformity: a magnetic resonance imaging study. Diabetes Care 2004;27:2376-81. 12. van der Ven, V, Chapman CB, Bowker JH. Charcot neuroarthropathy of the foot and ankle. J Am Acad Orthop Surg 2009;17:562-71. 13. Bus SA, Maas M, de Lange LA, Michels RP, Levi M. Elevated plantar pressures in neuropathic diabetic patients with claw/hammer toe deformity. J Biomech 2005;38:1918-25. 14. Armstrong DG, Lavery LA. Elevated peak plantar pressures in patients who have Charcot arthropathy. J Bone Joint Surg Am 1998;80:365-9. 15. Pound N, Chipchase S, Treece K, Game F, Jeffcoate W. Ulcer-free survival following management of foot ulcers in diabetes. Diabet Med 2005;22:1306-9. 16. Lavery LA, Vela SA, Fleischli JG, Armstrong DG, Lavery DC. Reducing plantar pressure in the neuropathic foot. A comparison of footwear. Diabetes Care 1997;20:1706-10. 17. Fleischli JG, Lavery LA, Vela SA, Ashry H, Lavery DC. Comparison of strategies for reducing pressure at the site of neuropathic ulcers. J Am Podiatr Med Assoc 1997;87:466-72. 18. Beuker BJ, van Deursen RW, Price P, Manning EA, van Baal JG, Harding KG. Plantar pressure in off-loading devices used in diabetic ulcer treatment. Wound Repair Regen 2005;13:537-42. 19. Nagel A, Rosenbaum D. Vacuum cushioned removable cast walkers reduce foot loading in patients with diabetes mellitus. Gait Posture 2009;30:11-5. 20. Shaw JE, Hsi WL, Ulbrecht JS, Norkitis A, Becker MB, Cavanagh PR. The mechanism of plantar unloading in total contact casts: implications for design and clinical use. Foot Ankle Int 1997;18:809-17. 21. Bus SA, Waaijman R, Arts M, Manning H. The efficacy of a removable vacuum-cushioned cast replacement system in reducing plantar forefoot pressures in diabetic patients. Clin Biomech (Bristol, Avon) 2009;24: 459-64. 22. Bus SA, van Deursen RW, Kanade RV, Wissink M, Manning EA, van Baal JG, et al. Plantar pressure relief in the diabetic foot using forefoot offloading shoes. Gait Posture 2009;29:618-22. 23. Bus SA, Ulbrecht JS, Cavanagh PR. Pressure relief and load redistribution by custom-made insoles in diabetic patients with neuropathy and foot deformity. Clin Biomech 2004;19:629-38. 24. Guldemond NA, Leffers P, Schaper NC, Sanders AP, Nieman F, Willems P, et al. The effects of insole configurations on forefoot plantar pressure and walking convenience in diabetic patients with neuropathic feet. Clin Biomech 2007;22:81-7. 25. Praet SF, Louwerens JW. The influence of shoe design on plantar pressures in neuropathic feet. Diabetes Care 2003;26:441-5. 26. van Schie C, Ulbrecht JS, Becker MB, Cavanagh PR. Design criteria for rigid rocker shoes. Foot Ankle Int 2000;21:833-44. 27. Schaff PS, Cavanagh PR. Shoes for the insensitive foot: the effect of a “rocker bottom” shoe modification on plantar pressure distribution. Foot Ankle 1990;11:129-40. 28. Lord M, Hosein R. Pressure redistribution by molded inserts in diabetic footwear: a pilot study. J Rehabil Res Dev 1994;31:214-21. 29. van Schie CH, Whalley A, Armstrong DG, Vileikyte L, Boulton AJ. The effect of silicone injections in the diabetic foot on peak plantar pressure and plantar tissue thickness: a 2-year follow-up. Arch Phys Med Rehabil 2002;83:919-23. 30. Maluf KS, Mueller MJ, Strube MJ, Engsberg JR, Johnson JE. Tendon Achilles lengthening for the treatment of neuropathic ulcers causes a temporary reduction in forefoot pressure associated with changes in plantar flexor power rather than ankle motion during gait. J Biomech 2004;37:897-906. 31. Pitei DL, Foster A, Edmonds M. The effect of regular callus removal on foot pressures. J Foot Ankle Surg 1999;38:251-5.
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32. Young MJ, Cavanagh PR, Thomas G, Johnson MM, Murray H, Boulton AJ. The effect of callus removal on dynamic plantar foot pressures in diabetic patients. Diabet Med 1992;9:55-7. 33. Mueller MJ, Diamond JE, Sinacore DR, Delitto A, Blair VP 3rd, Drury DA, et al. Total contact casting in treatment of diabetic plantar ulcers. Controlled clinical trial. Diabetes Care 1989;12:384-8. 34. Armstrong DG, Nguyen HC, Lavery LA, van Schie CH, Boulton AJ, Harkless LB. Off-loading the diabetic foot wound: a randomized clinical trial. Diabetes Care 2001;24:1019-22. 35. Caravaggi C, Faglia E, De Giglio R, Mantero M, Quarantiello A, Sommariva E, et al. Effectiveness and safety of a nonremovable fiberglass off-bearing cast versus a therapeutic shoe in the treatment of neuropathic foot ulcers: a randomized study. Diabetes Care 2000;23: 1746-51. 36. Ha VG, Siney H, Hartmann-Heurtier A, Jacqueminet S, Greau F, Grimaldi A. Nonremovable, windowed, fiberglass cast boot in the treatment of diabetic plantar ulcers: efficacy, safety, and compliance. Diabetes Care 2003;26:2848-52. 37. Ezio F, Carlo C, Giacomo C, Adriana S, Vincenzo C, Vanda V, et al. Effectiveness of removable waler cast versus non-removable fiberglass off-bearing cast in the healing of diabetic plantar foot ulcer- a randomized controlled trial. Diabetes Care 2010 [E-pub: doi: 10.2337/dc091708]. 38. Diamond JE, Mueller MJ, Delitto A. Effect of total contact cast immobilization on subtalar and talocrural joint motion in patients with diabetes mellitus. Phys Ther 1993;73:310-5. 39. Baker RE. Total contact casting. J Am Podiatr Med Assoc 1995;85: 172-6. 40. Armstrong DG, Lavery LA, Bushman TR. Peak foot pressures influence the healing time of diabetic foot ulcers treated with total contact casts. J Rehabil Res Dev 1998;35:1-5. 41. Lin SS, Lee TH, Wapner KL. Plantar forefoot ulceration with equinus deformity of the ankle in diabetic patients: the effect of tendo-Achilles lengthening and total contact casting. Orthopedics 1996;19:465-75. 42. Boulton AJ, Bowker JH, Gadia M, Lemerman R, Caswell K, Skyler JS, et al. Use of plaster casts in the management of diabetic neuropathic foot ulcers. Diabetes Care 1986;9:149-52. 43. Walker SC, Helm PA, Pullium G. Total contact casting and chronic diabetic neuropathic foot ulcerations: healing rates by wound location. Arch Phys Med Rehabil 1987;68:217-21. 44. Sinacore DR, Mueller MJ, Diamond JE, Blair VP, III, Drury D, Rose SJ. Diabetic plantar ulcers treated by total contact casting. A clinical report. Phys Ther 1987;67:1543-9. 45. Laing PW, Cogley DI, Klenerman L. Neuropathic foot ulceration treated by total contact casts. J Bone Joint Surg Br 1992;74:133-6. 46. Birke JA, Novick A, Graham SL, Coleman WC, Brasseaux DM. Methods of treating plantar ulcers. Phys Ther 1991;71:116-22. 47. Piaggesi A, Macchiarini S, Rizzo L, Palumbo F, Tedeschi A, Nobili LA, et al. An off-the-shelf instant contact casting device for the management of diabetic foot ulcers: a randomized prospective trial versus traditional fiberglass cast. Diabetes Care 2007;30:586-90. 48. Katz IA, Harlan A, Miranda-Palma B, Prieto-Sanchez L, Armstrong DG, Bowker JH, et al. A randomized trial of two irremovable offloading devices in the management of plantar neuropathic diabetic foot ulcers. Diabetes Care 2005;28:555-9. 49. Armstrong DG, Lavery LA, Wu S, Boulton AJ. Evaluation of removable and irremovable cast walkers in the healing of diabetic foot wounds: a randomized controlled trial. Diabetes Care 2005;28:551-4. 50. Armstrong DG, Lavery LA, Kimbriel HR, Nixon BP, Boulton AJ. Activity patterns of patients with diabetic foot ulceration: patients with active ulceration may not adhere to a standard pressure off-loading regimen. Diabetes Care 2003;26:2595-7. 51. Hissink RJ, Manning HA, van Baal JG. The MABAL shoe, an alternative method in contact casting for the treatment of neuropathic diabetic foot ulcers. Foot Ankle Int 2000;21:320-3. 52. Chantelau E, Breuer U, Leisch AC, Tanudjaja T, Reuter M. Outpatient treatment of unilateral diabetic foot ulcers with ‘half shoes.’ Diabet Med 1993;10:267-70.
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53. Knowles EA, Armstrong DG, Hayat SA, Khawaja KI, Malik RA, Boulton AJ. Offloading diabetic foot wounds using the scotchcast boot: a retrospective study. Ostomy Wound Manage 2002;48:50-3. 54. Dumont IJ, Lepeut MS, Tsirtsikolou DM, Popielarz SM, Cordonnier MM, Fayard AJ, et al. A proof-of-concept study of the effectiveness of a removable device for offloading in patients with neuropathic ulceration of the foot: the Ransart boot. Diabet Med 2009;26:778-82. 55. Van De Weg FB, Van Der Windt DA, Vahl AC. Wound healing: total contact cast vs. custom-made temporary footwear for patients with diabetic foot ulceration. Prosthet Orthot Int 2008;32:3-11. 56. Mueller MJ, Sinacore DR, Hastings MK, Strube MJ, Johnson JE. Effect of Achilles tendon lengthening on neuropathic plantar ulcers. A randomized clinical trial. J Bone Joint Surg Am 2003;85:1436-45. 57. Piaggesi A, Schipani E, Campi F, Romanelli M, Baccetti F, Arvia C, et al. Conservative surgical approach versus non-surgical management for diabetic neuropathic foot ulcers: a randomized trial. Diabet Med 1998; 15:412-7. 58. Armstrong DG, Rosales MA, Gashi A. Efficacy of fifth metatarsal head resection for treatment of chronic diabetic foot ulceration. J Am Podiatr Med Assoc 2005;95:353-6. 59. Armstrong DG, Lavery LA, Vazquez JR, Short B, Kimbriel HR, Nixon BP, et al. Clinical efficacy of the first metatarsophalangeal joint arthroplasty as a curative procedure for hallux interphalangeal joint wounds in patients with diabetes. Diabetes Care 2003;26:3284-328. 60. Lin SS, Bono CM, Lee TH. Total contact casting and Keller arthoplasty for diabetic great toe ulceration under the interphalangeal joint. Foot Ankle Int 2000;21:588-93. 61. Nabuurs-Franssen MH, Sleegers R, Huijberts MS, Wijnen W, Sanders AP, Walenkamp G, et al. Total contact casting of the diabetic foot in daily practice: a prospective follow-up study. Diabetes Care 2005;28:243-7. 62. Uccioli L, Faglia E, Monticone G, Favales F, Durola L, Aldeghi A, et al. Manufactured shoes in the prevention of diabetic foot ulcers. Diabetes Care 1995;18:1376-8. 63. Litzelman DK, Marriott DJ, Vinicor F. The role of footwear in the prevention of foot lesions in patients with NIDDM. Conventional wisdom or evidence-based practice? Diabetes Care 1997;20:156-62. 64. Dargis V, Pantelejeva O, Jonushaite A, Vileikyte L, Boulton AJ. Benefits of a multidisciplinary approach in the management of recurrent diabetic foot ulceration in Lithuania: a prospective study. Diabetes Care 1999; 22:1428-31. 65. Viswanathan V, Madhavan S, Gnanasundaram S, Gopalakrishna G, Das BN, Rajasekar S, et al. Effectiveness of different types of footwear insoles for the diabetic neuropathic foot: a follow-up study. Diabetes Care 2004;27:474-7. 66. Reiber GE, Smith DG, Wallace C, Sullivan K, Hayes S, Vath C, et al. Effect of therapeutic footwear on foot reulceration in patients with diabetes: a randomized controlled trial. JAMA 2002;287:2552-8.
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