545422 research-article2014
POI0010.1177/0309364614545422Prosthetics and Orthotics InternationalRobinson et al.
INTERNATIONAL SOCIETY FOR PROSTHETICS AND ORTHOTICS
Expert Clinical View Point
Orthotic management of the neuropathic foot: An interdisciplinary care perspective
Prosthetics and Orthotics International 2015, Vol. 39(1) 73–81 © The International Society for Prosthetics and Orthotics 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0309364614545422 poi.sagepub.com
Christopher Robinson1, Matthew J Major1, Charles Kuffel2, Kevin Hines2 and Pamela Cole3
Abstract Background: Clinical management of the patient with neuropathic foot is becoming commonplace in orthotic clinics worldwide. The presentations that can result from neuropathic foot are diverse, requiring clinicians to understand the pathomechanics of ulceration, infection, and Charcot joint arthropathy to provide effective interventions. Objectives: The purpose of this clinical perspective is to provide a review of the literature regarding clinical concepts associated with orthotic management of neuropathic foot. Study design: Literature review and clinical case study. Methods: Relevant literature were reviewed and summarized, and a clinical case study synthesizing reviewed concepts was presented. Results: Given the multifactorial nature of the neuropathic foot, treatments must be multifaceted and patient-specific to effectively address the underlying disease processes. While systemic issues such as peripheral arterial disease are treated by physicians, local issues such as foot deformity are managed by orthotists. Orthotic interventions commonly include custom footwear to reduce the risk of ulceration through creation of a protective environment or targeted plantar offloading. Patient and caregiver education to encourage management compliance is equally as important to ensure successful treatment. Conclusion: Patients with neuropathic foot benefit from an interdisciplinary care approach which engages physicians, wound care practitioners, and orthotists to treat and manage systemic and local problems. Addressing this pathology through interdisciplinary care may positively affect the patient’s health status while lowering associated healthcare costs through improved treatment efficacy. Clinical relevance The commonality of neuropathic foot and associated complications including ulceration, infection, and Charcot joint arthropathy requires that the patient care team have a fundamental understanding of these pathologies and common treatment modalities. We review orthotic treatment modalities to assist clinicians with the management of patients with neuropathic foot. Keywords The diabetic foot, diabetes, lower limb orthotics, orthotics, wound management, skin Date received: 31 March 2014; accepted: 16 June 2014
Background Diabetes affects approximately 7%–8.3% of the US population, which equates to over 22 million people.1,2 Of potentially greater concern is the fact that that 7 million of the patients with diabetes in the United States are unaware that they even have the disease.2 Diabetes is not only a major clinical challenge in the United States, as it is estimated that almost 200 million people worldwide have diabetes and there is a potential for this number to grow as high as 552 million by 2030 based upon population growth and inadequate access to healthcare resources globally.3,4 The current healthcare climate demands consideration of
the immense strain that diabetes places on the resources of our healthcare systems. The total cost to treat diabetes and its related conditions in the United States is estimated to be 1Jesse
Brown VA Medical Center, Northwestern University, Chicago, IL, USA 2Arise Orthotics & Prosthetics, Inc., Blaine, MN, USA 3Methodist Hospital Wound Clinic, St. Louis Park, MN, USA Corresponding author: Christopher Robinson, Northwestern University, 680 N Lake Shore Drive, Chicago, IL 60611, USA. Email: [email protected]
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Figure 1. Clinical algorithm describing pathways that can lead to ulceration.13 Source: reprinted with permission from John Wiley & Sons, Inc.
US$14 billion annually.5 Neuropathic foot complications account for 20% of all inpatient days for patients with diabetes in the United States and is estimated to cost £252 million annually in the United Kingdom.6,7 Treatment of each neuropathic ulcer costs between US$7000 and US$28,000 depending on the locality and magnitude of treatment required. If amputation is needed, the expense may be upward of US$50,000–US$60,000.3,8,9 Despite the volume of scholarly literature on the topic of neuropathic foot and its support for interdisciplinary care team management, the rate of ulceration continues to increase at approximately 2% per year.3 This increase in ulceration may ultimately translate to increased expense and burden to the healthcare system.3 However, interdisciplinary care teams, including orthotists and wound care specialists, that collaboratively manage neuropathic ulceration are a potentially effective solution to minimizing these costs. It has been suggested that 50%–75% of amputations are preventable with early diagnosis of diabetes and its associated complications combined with appropriate treatment by an interdisciplinary care team including orthotics practitioners.5,10,11 A multi-center trial in Italy using this model of management succeeded in reducing the cost by €107,505 annually preventing 55 diabetic foot ulcers per year in the population that received orthotic management as part of their interdisciplinary care.12 The multifactorial nature of foot ulceration requires the clinician to understand the interplay between local and systemic factors in order to design the most effective treatment plan. The clinical algorithm proposed by Boulton13 (Figure 1) illustrates the interplay of the contributing factors and the pathways that can lead to ulceration. Essentially, ulceration is a multifactorial condition that
arises from a combination of systemic and localized problems.1,3,6,8,11,14 Systemic complications of diabetes include hyperglycemia, peripheral arterial disease, and neuropathy.4,5,8,14 Hyperglycemia secondary to poorly managed blood glucose can result in increased stiffness and reduced elasticity of plantar tissue, compromising its ability to tolerate sheer forces.6 Systemic issues can increase the likelihood of developing a wound and often occur in concert with localized issues versus in isolation.6,11 Of all the systemic complications of diabetes, evidence suggests that sensory neuropathy is the most prominent risk factor for ulceration.14 Importantly, the combination of sensory neuropathy, minor foot trauma, and deformity accounts for over 50% of diabetic ulcers.14 Local problems include the presence of hyperkeratotic lesions, foot deformity, rangeof-motion (ROM) limitations, improper footwear, and a history of previous ulceration.1,8 Hyperkeratotic lesions and foot deformities create focal points for ulceration to occur, while decreased ROM of the joints in the lower limb and improperly fit footwear can result in greater than typical forces during weight-bearing activity.6,15,16 Furthermore, a history of ulceration elevates the patient’s risk of sustaining a new wound given that the resultant tissue after healing lacks the tensile strength of the original structure.4 Given the multifactorial nature of the neuropathic foot and its associated complications, treatments must also be multifaceted and tailored to each individual patient’s needs. Regardless of the underlying factors such as neuropathy or abnormality, there is a general consensus that the underlying disease processes must be addressed if the practitioner hopes to achieve long-term success.4 Management of the neuropathic foot requires the interdisciplinary team to address both systemic and local
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Robinson et al. problems, while providing the patient and their caregivers adequate education to ensure compliance to the proposed treatment plan. A practical illustration of the interplay between systemic and local factors is patients with diabetes that lack a normal immunoresponse, which enables infection to more easily spread and cause potentially irreparable damage if not promptly addressed.1 Tissue damage secondary to infection, which is the second most common complication of neuropathic foot,11 can subsequently require modification to a patient’s treatment needs, including orthotic management if the patient’s limb volume has changed or a surface-based treatment is implemented by the wound care team. For example, alginate or foam-based dressings can be implemented to control the wound exudate, but they require adequate space within the orthosis to function optimally.17 Another complication of neuropathic foot that will shape the clinical decision-making process with regard to orthotic management is Charcot joint arthropathy. Charcot joint arthropathy is developed by just 1% of patients with neuropathic foot and is believed to be a result of combined sensory neuropathy, normal circulation, and preceding foot trauma.1,17,18 To facilitate diagnosis and clinical decision making, multiple classification systems have been developed to quantify and categorize Charcot joint arthropathy. Classification systems for Charcot joint arthropathy are based upon either the natural history of the disease or affected joint structures. A common classification system based on natural history is the Eichenholtz and modified Eichenholtz classification systems.6,18,19 The original Eichenholtz classification system defines three stages: (I) acute inflammatory, (II) healing, and (III) chronic, while the modified Eichenholtz system added an initial stage referred to as pre-stage I or stage 0 (Table 1).19 The Sanders and Frykberg classification system is useful for classifying the joints affected by Charcot joint arthropathy (Table 2), with locations ranging from distal/anterior to proximal/ anterior.1,20 For example, the most common type of Charcot joint arthropathy as defined by the Sanders and Frykberg1 classification is “type II,” which occurs at the tarsometatarsal joints often resulting in “rocker bottom foot” deformity. While systemic issues are most often treated by physicians, local issues are addressed by a collaborative effort of a wound care practitioner and a prosthetist/orthotist. Offloading sensitive areas to minimize applied pressure and/or sheer, while simultaneously increasing applied pressure to more tolerant areas, is often the primary goal when treating the neuropathic foot in order to decrease the risk of ulceration.12,13 The greater the magnitude of offloading, the more likely a wound is to heal, with common orthotic modalities reducing peak plantar pressures between 20% and 80%.15 A treatment as simple as providing properly fit footwear can facilitate wound healing and
Table 1. Modified Eichenholtz19 classification. Stage
Definition
Clinical presentation
O
Patients at risk of Charcot joint Development– fragmentation
Diabetic neuropathy and an acute sprain or fracture Erythema, edema, and increased warmth, usually absence of pain Diminution of erythema, edema, and warmth; decreased joint mobility Erythema, edema, and warmth are no longer present; ulcers at sites of residual deformity
I II
Coalescence
III
Reconstruction– consolidation
Table 2. Sanders and Frykberg20 classification. Classification
Anatomical location of joint involvement
I II III
Forefoot Tarsometatarsal Naviculocuneiform, talonavicular, calcaneocuboid joints Ankle and subtalar joints Calcaneus
IV V
prevent recurrence, although more complicated cases will require more involved orthotic management.16 There is evidence to support that orthotic modalities are acceptable methods for offloading of ulceration21 and that the implementation of protective footwear can reduce the incidence of future ulceration.22 Finally, a treatment that must not be overlooked is effective patient and caregiver education.1,8 Although positive clinical outcomes for the management of neuropathic foot have been attributed to interdisciplinary care, patient adherence to the wear of orthotic interventions, home wound care plans, and an understanding of their overall health condition are all equally important in ensuring successful treatment. The patient must have a clear understanding of the aims of their treatment, be able to identify worsening symptoms, and be proactive about communicating with their healthcare team to treat a new wound as expeditiously as possible. However, for this treatment to be successful, the patient must be informed and open to communication with their healthcare team.4 Diabetes and associated neuropathic foot are clinical challenges faced by practitioners worldwide. As incidence of neuropathic foot and its associated complications rise, it is imperative that orthotic practitioners have a sound understanding of the clinical principles that underlie effective management of patients with these conditions. The aim of this article is to provide the clinician with a multidisciplinary perspective on the management of
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neuropathic foot, describe orthotic modalities commonly implemented to treat ulceration and Charcot joint arthropathy, provide a clinical case study of interdisciplinary care, and generally discuss pertinent topics to consider when managing the neuropathic foot.
Treating the neuropathic foot: an orthotist’s perspective The neuropathic foot is one of the most challenging clinical scenarios that an orthotist can manage. The practitioner must not only perform a comprehensive examination of the client and formulate an individualized treatment plan including an appropriate orthotic modality but also provide the education required to achieve an appropriate clinical outcome. Failure to provide an appropriate intervention and necessary education may preclude successful treatment and further compromise the patient’s already delicate health condition. Preventative screening for these clinical problems is essential to identify those individuals who are most at risk. A common screening technique to assess for the presence of peripheral neuropathy is the Lower Extremity Amputation Prevention (LEAP) program.5,23 The five-step LEAP protocol includes the following: (1) an annual foot screening, (2) patient education, (3) daily self-inspection, (4) proper footwear selection, and (5) management of simple foot problems.5 The annual foot screening protocol of the LEAP program provides the orthotist with clinical information to help identify those patients who are at risk of ulceration. This protocol consists of two components: standardized questionnaire and protective sensation assessment. The questionnaire instrument assesses factors including history of ulceration, deformity, swelling, callous, muscle weakness, and the fit of the patients’ footwear. The protective sensation assessment is completed with a 5.07 gauge monofilament to assess the extent of sensory neuropathy. In patients who have already lost protective sensation, the US Health Resources and Service Administration recommends an increase in frequency for the administration of the screening exam to every 3 months given their increased relative risk.24 Completion of the LEAP screening protocol informs the patient’s orthotic treatment plan and will provide context for education about their condition and potential complications. Verbal and written patient education on the management of diabetes and associated neuropathy not only engages the patient but also may prevent further complications.25 Through the introduction of simple self-management techniques, the patient will assume responsibility for their health by performing daily skin inspections, identifying problems, and treating simple foot problems such as dry skin. Early recognition of potential problems empowers the patient to pursue them before they manifest into
something more serious. Patient education is not complete unless the orthotist also stresses the importance of appropriate footwear and the need to wear the footwear even for activities within the patient’s home.24 Once the neuropathic foot patient has been thoroughly assessed and educated about their condition such that they have been provided the information necessary to monitor their condition, the orthotist can begin to formulate a treatment plan. Orthotic management must account for internal influences such as bony malformation or ROM limitations, skin integrity, and the patient’s ability to implement the selected intervention independently. In patients with no active ulceration, long-term maintenance of the neuropathic foot is often achieved through the use of depth inlay shoes and multi-density accommodative foot orthoses. Chronic foot ulceration and/or active Charcot joint arthropathy requires more aggressive orthotic management such as joint immobilization and unweighting to promote initial healing. The objective of this section is to provide practitioners with a fundamental understanding of the orthoses commonly used to treat neuropathic foot and discuss their appropriateness for managing the neuropathic patient. A practice framework exists for the wound care practitioner to affectively treat neuropathic ulceration, but it is important to note that no single modality can address the needs of every patient. It is essential that the wound care practitioner create a multifaceted treatment plan to address each patient’s unique clinical presentation. Regardless of the chosen wound care modalities, it is the responsibility of the orthotics practitioner to work collaboratively to create an interface between the patient’s foot and the ground that can enable initial healing and long-term mobility for the patient with the neuropathic foot.
Diabetic shoes and multi-durometer foot orthoses Depth inlay footwear for the treatment of neuropathic foot is designed to provide prophylactic protection and longterm management to the at-risk neuropathic population. The goal of depth inlay shoes is to provide a total protective environment to the dorsal and plantar aspects of the foot, while allowing adequate internal volume to accommodate off-the-shelf or custom multi-durometer foot orthoses and prevent impingement of the patient’s anatomy. A proper fit between the shoe and the patient’s foot and a seamless construction on the inside of the shoe is intended to minimize shear and pressure within this interface. The addition of an extended shank or full-length carbon fiber insert reinforces the shoe and limits motion at the midfoot and forefoot during stance. Depth inlay footwear may be lace-up and/or Velcro closure depending on the patient’s dexterity and personal preference. Diabetic shoes may be further enhanced by pedorthic modifications to accommodate fixed deformities or address atypical
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Figure 2. (a) Forefoot and (b) hindfoot offloading footwear (OrthoWedge and HeelWedge; DARCO International, Huntington, WV, USA).
kinetics/kinematics. Common pedorthic modifications include the application of a medial or lateral flare, sole lift, or a rocker sole, which can be used to widen the patient’s base of support, address atypical joint moments, accommodate a leg-length discrepancy, or augment stance phase timing.8 The diabetic shoe is typically provided in conjunction with multi-durometer foot orthoses which utilize varying densities of materials to provide a total contact interface between the neuropathic foot and the shoe. Patients with neuropathic foot often sustain higher than normal peak plantar pressures,26 and a total contact environment reduces areas of peak pressure as a result of increasing the affected surface area. Multi-durometer foot orthoses are either off-the-shelf or custom in design and are selected based on presentation of the plantar foot. Patients with excessive callusing, ulceration, or foot deformity often require custom-fabricated foot orthoses due to their unique anatomy, while prophylactic care of mild foot abnormalities is achieved through the use of offthe-shelf foot orthoses.
Offloading footwear An important component to comprehensive wound care involves the minimization of pressure and/or sheer at the site of the wound, known as offloading. Even with optimal local wound care, debridement, and dressings, the wound is unlikely to heal without the addition of an offloading modality to the treatment plan. Offloading is challenging because many modalities reduce patient function, vocation, and safety due to their weight and bulk. Various styles of offloading footwear to relieve pressure sensitive areas of the neuropathic foot are commercially available. The style of offloading footwear is a function of the region of the foot that requires offloading. Offloading footwear is rarely a definitive intervention and
often used as an interim protective measure while custom orthoses are being fabricated. Offloading footwear is typically used as a provisional intervention as it may not facilitate the same level of healing observed when using other common modalities such as the total contact cast or removable cast walker.27 Offloading footwear often relies on aggressive modifications to the sole of the footwear to achieve its affect, but these modifications may negatively impact gait by creating discomfort28 and encouraging changes in joint moments and pelvic obliquity.29 Furthermore, the sole thickness of common offloading shoe orthoses is frequently higher than the patient’s typical footwear and may result in a leg-length discrepancy that requires consideration. Forefoot offloading footwear (Figure 2(a)) is designed to provide pressure reduction in the metatarsal heads and phalanges. This type of offloading footwear typically places the ankle in a relatively dorsiflexed position and effectively shortens the amount of relative time spent in the forefoot rocker during the stance phase of gait, thereby reducing the duration of applied pressure to this region. Hindfoot offloading footwear (Figure 2(b)) is designed to limit the magnitude of forces imparted on the calcaneus. This is done by removing the sole area plantar to the hindfoot which forces initial contact to occur anterior to the calcaneus. Not all offloading footwear requires the use of rocker modifications to impart a biomechanical benefit. Various manufacturers provide healing shoes that are offloading footwear to allow for targeted reduction in plantar pressures through the removal of pre-punched pads in the included insert (Figure 3). Care should be taken with this intervention as leaving a large void below an ulcerative site can cause wound compromise as the tissues of the foot can displace into the void during weight-bearing activity. However, a minimal level of plantar surface pressure
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Figure 3. Össur DH offloading insole (Össur Americas, Aliso Viejo, CA, USA).
applied to the ulcerative area can be maintained by backfilling the voids with a lower durometer material. A substantial body of literature on plantar wound treatment suggests that total contact casting (TCC) is the gold standard of offloading modalities.3 TCCs distribute pressure across the foot, immobilize the foot and ankle joints, and distribute forces across a larger surface area of the patient’s limb. TCCs are typically changed once per week to enable the wound care practitioner to monitor, cleanse, debride, and re-apply dressings to the wound. Should the patient have poor ankle brachial index, heavy necrosis, and/or an active infection, the TCC can be fabricated such that it is removable in nature enabling more frequent inspection and dressing changes. The dilemma with a removable design is that it enables patients to more easily/ readily doff the TCC, which can hinder compliance and potentially compromise healing. Rapid TCCs, which use off-the-shelf walking boots with pneumatic bladders to redistribute pressure, are becoming a popular offloading solution as they require minimal customization and fabrication time. However, rapid TCCs lack the total contact throughout the patient’s limb as they are not contoured to the patient’s unique anatomy. If a bivalved TCC or rapid TCC is used for treatment, the patient must clearly understand that walking even a few steps without the support of the device may compromise the wound healing process and potentially cause the development of new wounds.
Custom orthotic management Comprehensive orthotic management for patients with Charcot joint arthropathy, active ulceration, or moderateto-severe bony deformity cannot often be addressed with an off-the-shelf intervention. Custom orthoses allow the orthotist to utilize appropriate materials and design
principles for the individual patient’s needs. Commonly implemented custom orthotic modalities are the Charcot restraint orthotic walker (CROW) orthosis, patellar tendon-bearing (PTB) orthosis, and conventional ankle–foot orthosis (AFO) with molded calf lacer. The CROW orthosis is a custom-fabricated bivalve orthosis designed to provide total contact to the plantar aspect of the foot, ankle, and calf designed to treat Charcot joint arthropathy and diabetic foot ulcers. Given that the CROW is custom fabricated, it can accommodate a wide array of foot and ankle deformities often seen when treating the patient with neuropathic foot.30 The CROW orthosis is worn to provide offloading, tri-planar restriction motion of the foot and ankle. The CROW is contraindicated for patients with large volume fluctuation as these changes can compromise the fit and functionality of the orthosis. The ease of doffing of the CROW orthosis allows easy dressing changes and monitoring of the wound area. In practice, the CROW orthosis is used for long-term management of Charcot joint arthropathy and ulceration where a TCC or off-the-shelf intervention is inappropriate. A PTB orthosis is designed to provide offloading of the plantar aspect of the foot by suspending the limb via pressure tolerant structures around the knee, such as the patellar tendon (ligament), popliteal fossa, and medial tibial flare. The proximal portion is fabricated from a thermoplastic or thermoset material and is attached to a conventional AFO with alloy sidebars and double action joints. Depth inlay shoes with multi-density inserts are installed distally to provide total contact to the plantar aspect of the foot. This type of orthosis better accommodates volumetric changes than the CROW orthosis as its relatively open design can accommodate volumetric increase while a volumetric decrease is accommodated with the application of sock ply prior to donning the orthosis. The integration of double action joints enables the practitioner to tune the orthosis to optimize kinematics for the minimization of forces applied to the patient’s neuropathic limb.5 The conventional AFO with molded calf lacer is custom fabricated from a cast of the patient’s limb. The objective of this orthosis is to provide unloading of the plantar aspect of the patient’s foot by circumferential loading of the calf musculature.31 Similar to the PTB-style AFO, the conventional orthosis will accommodate volume fluctuation of the limb as the molded calf lacer can be adjusted circumferentially by simply loosening or cinching the closer while donning. The distal portion of the orthosis consists of alloy sidebars and double action joints to attach the orthosis to depth inlay footwear with a multi-density insert. The conventional AFO with molded calf lacer is an effective modality during acute, sub-acute, and long-term management of plantar ulceration. Regardless of the orthotic modality, the interdisciplinary care team must work closely to ensure the patient is phased into the appropriate intervention. Potentially
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Figure 4. (a) Wound on the lateral aspect of the patient’s left lower limb status post partial resection of the calcaneus and fifth metatarsal and (b) initial wound closure after the implementation of a PTB orthosis. PTB: patellar tendon bearing.
cumbersome interventions such as the CROW should be discontinued when the patient is a candidate for a less restrictive intervention such as custom shoes and inserts. Simply observing wound closure is not adequate justification as it takes 3 months for scar tissue to remodel and achieve 80% of its original tensile strength.32 Application of excess pressure on a recently closed wound from premature weaning into diabetic shoes could increase the risk for re-ulceration as the tissues have only 20% of its final tensile strength at 3 weeks following the scarring onset.
Clinical case study Patient history The patient was a 49-year-old female (165 cm, 102 kg) with type 2 diabetes, bilateral plantar sensory neuropathy, and type III Charcot joint arthropathy with a recently debrided diabetic foot ulcer on the right lower limb and a wound spanning the lateral aspect of the calcaneus, cuboid, and fifth metatarsal that was recently closed with a splitthickness skin graft. The patient stated that the ulcer on the right limb developed 7 months prior to the consultation and the Charcot joint arthropathy was diagnosed 10 months prior, although they stated that they were initially misdiagnosed with cellulitis. The wound on the left foot developed after the patient sustained a hematoma from striking their foot against the orthosis on the right foot, which eventually resulted in the need to perform a partial resection of the calcaneus and fifth metatarsal (Figure 4). The wound beds were clear and the edges were free from necrotic tissue. Previous orthotic management included an off-the-shelf pneumatic walking boot with a custom multi-density foot orthosis and a healing sandal with practitioner adjustable multi-density insole (Figure 3) on the right limb. The left lower limb had not been managed with an orthotic intervention and the patient utilized a kneeling scooter for
unweighting of the left foot skin graft area at the time of consultation.
Patient evaluation Hammer toes were observed bilaterally at digits 2–3 and the skin appeared to be dry and flaky with callous present on the plantar aspect of the calcaneus bilaterally and proximal to the Charcot joint at the midfoot of the right limb. The patient’s left foot presented in forefoot adduction likely due to changes associated with the recent osseous resections. A 5.07 gauge monofilament was used to assess for the presence of neuropathy, and findings were consistent with the presence of peripheral neuropathy as the patient could not identify the presence of the monofilament at any point on the plantar aspect of their foot. The patient’s lower limb passive ROM and strength were assessed bilaterally in a seated non-weight-bearing position. Both lower limbs were found to have hip and knee ROM within functional limits. Ankle ROM was assessed with the knee in terminal extension, and a plantar grade or neutral position was achieved bilaterally, but no additional dorsiflexion was available. Decreased mobility was noted at the midfoot joints bilaterally secondary to surgical intervention on the right limb and Charcot joint arthropathy on the left side. Bilateral manual muscle test findings revealed right–left symmetric muscle strength, with all lower extremity muscle groups demonstrating strength at a level of 4/5, apart from ankle dorsiflexor and plantar strength which were scored as 3/5.
Treatment Bilateral impressions were taken in a non-weight-bearing position with the knees in terminal extension to better reflect ankle alignment during ambulation for the fabrication of bilateral CROW orthoses. The positive model was rectified with 3-mm build-ups placed over the Charcot joint
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at the midfoot of the right limb and the skin graft over the lateral aspect of the foot on the left limb. The orthoses were fabricated from 3/16″ copolymer with a soft-density polyethylene foam liner and removable multi-durometer insole. The reliefs were back-filled with pink Plastazote (Algeos USA, Santa Monica, CA, USA) to restore total contact with the limb and then covered with ShearBan (Tamarack Habilitation Technologies Inc., Blaine, MN, USA) to minimize friction over the compromised areas. A rocker bottom sole was fabricated from crepe to enable adjustments to the rocker profile and height during the fitting process.
Follow-up The patient was closely followed with bi-monthly visits to the orthotics team and wound care specialist over a 6-month period of time. Adjustments were made to the CROW boots to maintain total contact throughout the patient’s lower limbs due to volumetric or anatomical contour changes. The wound on the plantar aspect of the right foot was healed during the 6 months of immobilization in the CROW. The wound on the lateral aspect of the foot increased in diameter and was migrating over the foot perimeter to the plantar aspect. This was further compromised by excessive wound exudate which resulted in skin maceration and the need for increased frequency of dressing changes.
Figure 5. Side view of the leather unweighting orthosis.
Conclusion Secondary treatment Six months after the CROW orthoses were provided, the clinical team decided to transition the patient into bilateral leather unweighting orthoses attached to a conventional AFO with alloy sidebars and double action joints locked at 90° (Figure 5). The AFOs were attached to a pair of custom-made shoes, and the patient was instructed to wear the AFOs full time during weight-bearing activity. After 3 months of management with the unweighting orthoses, the right plantar wound remained healed, but the wound on the left foot demonstrated minimal improvement. The left foot wound had deepened in the area of the base of fifth metatarsal and forcing the patient’s vascular surgeon to pursue the removal of the base of the fifth metatarsal to better facilitate wound healing. The leather unweighting AFOs were used full time for ambulation after the resection of the base of the fifth metatarsal in conjunction with continued wound debridement and dressing changes. The wound on the lateral aspect of the left foot closed 7 months after the resection of the base of the fifth metatarsal. The patient continued to utilize the conventional AFOs with molded calf lacers after the successful wound closure in order for the scar tissue to maturate and continue to remodel with type I collagen fibers.
The clinical management of the neuropathic foot requires careful consideration of each patient’s unique needs to effectively address the systemic and local issues for ensuring successful intervention. Effective management facilitates wound healing and prevention to avert further complications and subsequent amputation. Given the multifactorial nature of the pathology, there is no single model for interdisciplinary care. However, a collaborative effort between relevant healthcare providers may positively affect the patient’s health status while lowering associated costs under certain circumstances. Acknowledgements The ideas presented in this article would not have been possible without the insights of and discussions with colleagues Marty Carlson, MS, CPO, and Wieland Kaphingst, Dipl.-Ing., CPO, FAAOP.
Author contribution All authors contributed equally in the preparation of this manuscript.
Declaration of conflicting interests Charles Kuffel is a paid consultant of Tamarack Habilitation Technologies Inc. (Blaine, MN, USA).
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Robinson et al. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
References 1. Frykberg RG, Zgonis T, Armstrong D, et al. Diabetic foot disorders: a clinical practice guide. J Foot Ankle Surg 2006; 45(5 Suppl.): S1–S66. 2. Centers for Disease Control and Prevention. National diabetes fact sheet, http://www.cdc.gov/diabetes/pubs/pdf/ndfs_2011. pdf 3. Lewis J and Lipp A. Pressure-relieving interventions for treating diabetic foot ulcers. Cochrane Database Syst Rev 2013; 1: CD002302. 4. Chadwick P, Edmonds M, McCardle J, et al. International best practice guidelines: wound management in diabetic foot ulcers. Wounds Int 2013; 4: 1–20. 5. Elftman N. Management of the neuropathic limb. J Prosthet Orthot 2005; 17: 4–36. 6. Skinner H. Current diagnosis & treatment in orthopedics. 5th ed. New York: McGraw-Hill Professional, 2013. 7. Paton J, Bruce G, Jones R, et al. Effectiveness of insoles used for the prevention of ulceration in the neuropathic diabetic foot: a systematic review. J Diabetes Complications 2011; 25: 52–62. 8. Cavanagh PR, Lipsky BA, Bradbury AW, et al. Treatment for diabetic foot ulcers. Lancet 2005; 366: 1725–1735. 9. McKea S, Ross JJ, Dressler DD, et al. Principles and practice of hospital medicine. 1st ed. New York: McGraw-Hill Medical, 2012, p.2310. 10. Halter J, Ouslander J, Tinetti M, et al. Hazzard’s geriatric medicine and gerontology. 6th ed. New York: McGraw-Hill Professional, 2009, p.1760. 11. Boulton AJ. The diabetic foot. Medicine 2010; 38: 644–648. 12. Rizzo L, Tedeschi A, Fallani E, et al. Custom-made orthesis and shoes in a structured follow-up program reduces the incidence of neuropathic ulcers in high-risk diabetic foot patients. Int J Low Extrem Wounds 2012; 11: 59–64. 13. Boulton AJ. The pathogenesis of diabetic foot problems: an overview. Diabet Med 1996; 13(Suppl. 1): S12–S16. 14. Leung PC. Diabetic foot ulcers—a comprehensive review. Surgeon 2007; 5: 219–231. 15. Bus SA. Priorities in offloading the diabetic foot. Diabetes Metab Res Rev 2012; 28: 54–59.
16. Sussman C, Strauss M, Barry DD, et al. Considerations of motor neuropathy for managing the neuropathic foot. J Prosthet Orthot 2005; 17: 28–31. 17. International best practice guidelines: wound management in diabetic foot ulcers. Wounds Int 2013, www.woundsinternational.com 18. Wukich DK and Sung W. Charcot arthropathy of the foot and ankle: modern concepts and management review. J Diabetes Complications 2009; 23: 409–426. 19. Eichenholtz SN. Charcot joints. Springfield, IL: Charles C Thomas Publisher, Ltd, 1966. 20. Sanders LJ and Frykberg RG. The high risk foot in diabetes mellitus. New York: Churchill Livingstone, 1991. 21. McGuire J. Transitional off-loading: an evidence-based approach to pressure redistribution in the diabetic foot. Adv Skin Wound Care 2010; 23: 175–188; quiz 89–90. 22. Steed DL, Attinger C, Colaizzi T, et al. Guidelines for the treatment of diabetic ulcers. Wound Repair Regen 2006; 14: 680–692. 23. Yang M, Zheng H, Wang H, et al. iGAIT: an interactive accelerometer based gait analysis system. Comput Methods Programs Biomed 2012; 108: 715–723. 24. US Department of Health and Human Services. Lower Extremity Amputation Prevention (LEAP), http://www. hrsa.gov/hansensdisease/leap/ 25. Crawford PE, Fields-Varnado M and Society W. Guideline for the management of wounds in patients with lowerextremity neuropathic disease: an executive summary. J Wound Ostomy Continence Nurs 2013; 40: 34–45. 26. Kim PJ. Biomechanics of the diabetic foot: consideration in limb salvage. Adv Wound Care 2013; 2: 107–111. 27. Armstrong DG, Nguyen HC, Lavery LA, et al. Off-loading the diabetic foot wound: a randomized clinical trial. Diabetes Care 2001; 24: 1019–1022. 28. Bus SA, Van Deursen RW, Kanade RV, et al. Plantar pressure relief in the diabetic foot using forefoot offloading shoes. Gait Posture 2009; 29: 618–622. 29. Wunnemann M, Klein D and Rosenbaum D. Effects of the Twin Shoe (Darco) to compensate height differences in normal gait. Gait Posture 2011; 33: 61–65. 30. Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. Hillsdale, NJ: Lawrence Erlbaum Associates, 1988. 31. Carlson JM, Hollerbach F and Day B. A calf corset weightbearing ankle foot orthosis design. J Prosthet Orthot 1991; 4: 41–44. 32. Witte MB and Barbul A. General principles of wound healing. Surg Clin North Am 1997; 77: 509–528.
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POI0010.1177/0309364614545422Prosthetics and Orthotics InternationalRobinson et al.
INTERNATIONAL SOCIETY FOR PROSTHETICS AND ORTHOTICS
Expert Clinical View Point
Orthotic management of the neuropathic foot: An interdisciplinary care perspective
Prosthetics and Orthotics International 2015, Vol. 39(1) 73–81 © The International Society for Prosthetics and Orthotics 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0309364614545422 poi.sagepub.com
Christopher Robinson1, Matthew J Major1, Charles Kuffel2, Kevin Hines2 and Pamela Cole3
Abstract Background: Clinical management of the patient with neuropathic foot is becoming commonplace in orthotic clinics worldwide. The presentations that can result from neuropathic foot are diverse, requiring clinicians to understand the pathomechanics of ulceration, infection, and Charcot joint arthropathy to provide effective interventions. Objectives: The purpose of this clinical perspective is to provide a review of the literature regarding clinical concepts associated with orthotic management of neuropathic foot. Study design: Literature review and clinical case study. Methods: Relevant literature were reviewed and summarized, and a clinical case study synthesizing reviewed concepts was presented. Results: Given the multifactorial nature of the neuropathic foot, treatments must be multifaceted and patient-specific to effectively address the underlying disease processes. While systemic issues such as peripheral arterial disease are treated by physicians, local issues such as foot deformity are managed by orthotists. Orthotic interventions commonly include custom footwear to reduce the risk of ulceration through creation of a protective environment or targeted plantar offloading. Patient and caregiver education to encourage management compliance is equally as important to ensure successful treatment. Conclusion: Patients with neuropathic foot benefit from an interdisciplinary care approach which engages physicians, wound care practitioners, and orthotists to treat and manage systemic and local problems. Addressing this pathology through interdisciplinary care may positively affect the patient’s health status while lowering associated healthcare costs through improved treatment efficacy. Clinical relevance The commonality of neuropathic foot and associated complications including ulceration, infection, and Charcot joint arthropathy requires that the patient care team have a fundamental understanding of these pathologies and common treatment modalities. We review orthotic treatment modalities to assist clinicians with the management of patients with neuropathic foot. Keywords The diabetic foot, diabetes, lower limb orthotics, orthotics, wound management, skin Date received: 31 March 2014; accepted: 16 June 2014
Background Diabetes affects approximately 7%–8.3% of the US population, which equates to over 22 million people.1,2 Of potentially greater concern is the fact that that 7 million of the patients with diabetes in the United States are unaware that they even have the disease.2 Diabetes is not only a major clinical challenge in the United States, as it is estimated that almost 200 million people worldwide have diabetes and there is a potential for this number to grow as high as 552 million by 2030 based upon population growth and inadequate access to healthcare resources globally.3,4 The current healthcare climate demands consideration of
the immense strain that diabetes places on the resources of our healthcare systems. The total cost to treat diabetes and its related conditions in the United States is estimated to be 1Jesse
Brown VA Medical Center, Northwestern University, Chicago, IL, USA 2Arise Orthotics & Prosthetics, Inc., Blaine, MN, USA 3Methodist Hospital Wound Clinic, St. Louis Park, MN, USA Corresponding author: Christopher Robinson, Northwestern University, 680 N Lake Shore Drive, Chicago, IL 60611, USA. Email: [email protected]
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Figure 1. Clinical algorithm describing pathways that can lead to ulceration.13 Source: reprinted with permission from John Wiley & Sons, Inc.
US$14 billion annually.5 Neuropathic foot complications account for 20% of all inpatient days for patients with diabetes in the United States and is estimated to cost £252 million annually in the United Kingdom.6,7 Treatment of each neuropathic ulcer costs between US$7000 and US$28,000 depending on the locality and magnitude of treatment required. If amputation is needed, the expense may be upward of US$50,000–US$60,000.3,8,9 Despite the volume of scholarly literature on the topic of neuropathic foot and its support for interdisciplinary care team management, the rate of ulceration continues to increase at approximately 2% per year.3 This increase in ulceration may ultimately translate to increased expense and burden to the healthcare system.3 However, interdisciplinary care teams, including orthotists and wound care specialists, that collaboratively manage neuropathic ulceration are a potentially effective solution to minimizing these costs. It has been suggested that 50%–75% of amputations are preventable with early diagnosis of diabetes and its associated complications combined with appropriate treatment by an interdisciplinary care team including orthotics practitioners.5,10,11 A multi-center trial in Italy using this model of management succeeded in reducing the cost by €107,505 annually preventing 55 diabetic foot ulcers per year in the population that received orthotic management as part of their interdisciplinary care.12 The multifactorial nature of foot ulceration requires the clinician to understand the interplay between local and systemic factors in order to design the most effective treatment plan. The clinical algorithm proposed by Boulton13 (Figure 1) illustrates the interplay of the contributing factors and the pathways that can lead to ulceration. Essentially, ulceration is a multifactorial condition that
arises from a combination of systemic and localized problems.1,3,6,8,11,14 Systemic complications of diabetes include hyperglycemia, peripheral arterial disease, and neuropathy.4,5,8,14 Hyperglycemia secondary to poorly managed blood glucose can result in increased stiffness and reduced elasticity of plantar tissue, compromising its ability to tolerate sheer forces.6 Systemic issues can increase the likelihood of developing a wound and often occur in concert with localized issues versus in isolation.6,11 Of all the systemic complications of diabetes, evidence suggests that sensory neuropathy is the most prominent risk factor for ulceration.14 Importantly, the combination of sensory neuropathy, minor foot trauma, and deformity accounts for over 50% of diabetic ulcers.14 Local problems include the presence of hyperkeratotic lesions, foot deformity, rangeof-motion (ROM) limitations, improper footwear, and a history of previous ulceration.1,8 Hyperkeratotic lesions and foot deformities create focal points for ulceration to occur, while decreased ROM of the joints in the lower limb and improperly fit footwear can result in greater than typical forces during weight-bearing activity.6,15,16 Furthermore, a history of ulceration elevates the patient’s risk of sustaining a new wound given that the resultant tissue after healing lacks the tensile strength of the original structure.4 Given the multifactorial nature of the neuropathic foot and its associated complications, treatments must also be multifaceted and tailored to each individual patient’s needs. Regardless of the underlying factors such as neuropathy or abnormality, there is a general consensus that the underlying disease processes must be addressed if the practitioner hopes to achieve long-term success.4 Management of the neuropathic foot requires the interdisciplinary team to address both systemic and local
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Robinson et al. problems, while providing the patient and their caregivers adequate education to ensure compliance to the proposed treatment plan. A practical illustration of the interplay between systemic and local factors is patients with diabetes that lack a normal immunoresponse, which enables infection to more easily spread and cause potentially irreparable damage if not promptly addressed.1 Tissue damage secondary to infection, which is the second most common complication of neuropathic foot,11 can subsequently require modification to a patient’s treatment needs, including orthotic management if the patient’s limb volume has changed or a surface-based treatment is implemented by the wound care team. For example, alginate or foam-based dressings can be implemented to control the wound exudate, but they require adequate space within the orthosis to function optimally.17 Another complication of neuropathic foot that will shape the clinical decision-making process with regard to orthotic management is Charcot joint arthropathy. Charcot joint arthropathy is developed by just 1% of patients with neuropathic foot and is believed to be a result of combined sensory neuropathy, normal circulation, and preceding foot trauma.1,17,18 To facilitate diagnosis and clinical decision making, multiple classification systems have been developed to quantify and categorize Charcot joint arthropathy. Classification systems for Charcot joint arthropathy are based upon either the natural history of the disease or affected joint structures. A common classification system based on natural history is the Eichenholtz and modified Eichenholtz classification systems.6,18,19 The original Eichenholtz classification system defines three stages: (I) acute inflammatory, (II) healing, and (III) chronic, while the modified Eichenholtz system added an initial stage referred to as pre-stage I or stage 0 (Table 1).19 The Sanders and Frykberg classification system is useful for classifying the joints affected by Charcot joint arthropathy (Table 2), with locations ranging from distal/anterior to proximal/ anterior.1,20 For example, the most common type of Charcot joint arthropathy as defined by the Sanders and Frykberg1 classification is “type II,” which occurs at the tarsometatarsal joints often resulting in “rocker bottom foot” deformity. While systemic issues are most often treated by physicians, local issues are addressed by a collaborative effort of a wound care practitioner and a prosthetist/orthotist. Offloading sensitive areas to minimize applied pressure and/or sheer, while simultaneously increasing applied pressure to more tolerant areas, is often the primary goal when treating the neuropathic foot in order to decrease the risk of ulceration.12,13 The greater the magnitude of offloading, the more likely a wound is to heal, with common orthotic modalities reducing peak plantar pressures between 20% and 80%.15 A treatment as simple as providing properly fit footwear can facilitate wound healing and
Table 1. Modified Eichenholtz19 classification. Stage
Definition
Clinical presentation
O
Patients at risk of Charcot joint Development– fragmentation
Diabetic neuropathy and an acute sprain or fracture Erythema, edema, and increased warmth, usually absence of pain Diminution of erythema, edema, and warmth; decreased joint mobility Erythema, edema, and warmth are no longer present; ulcers at sites of residual deformity
I II
Coalescence
III
Reconstruction– consolidation
Table 2. Sanders and Frykberg20 classification. Classification
Anatomical location of joint involvement
I II III
Forefoot Tarsometatarsal Naviculocuneiform, talonavicular, calcaneocuboid joints Ankle and subtalar joints Calcaneus
IV V
prevent recurrence, although more complicated cases will require more involved orthotic management.16 There is evidence to support that orthotic modalities are acceptable methods for offloading of ulceration21 and that the implementation of protective footwear can reduce the incidence of future ulceration.22 Finally, a treatment that must not be overlooked is effective patient and caregiver education.1,8 Although positive clinical outcomes for the management of neuropathic foot have been attributed to interdisciplinary care, patient adherence to the wear of orthotic interventions, home wound care plans, and an understanding of their overall health condition are all equally important in ensuring successful treatment. The patient must have a clear understanding of the aims of their treatment, be able to identify worsening symptoms, and be proactive about communicating with their healthcare team to treat a new wound as expeditiously as possible. However, for this treatment to be successful, the patient must be informed and open to communication with their healthcare team.4 Diabetes and associated neuropathic foot are clinical challenges faced by practitioners worldwide. As incidence of neuropathic foot and its associated complications rise, it is imperative that orthotic practitioners have a sound understanding of the clinical principles that underlie effective management of patients with these conditions. The aim of this article is to provide the clinician with a multidisciplinary perspective on the management of
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neuropathic foot, describe orthotic modalities commonly implemented to treat ulceration and Charcot joint arthropathy, provide a clinical case study of interdisciplinary care, and generally discuss pertinent topics to consider when managing the neuropathic foot.
Treating the neuropathic foot: an orthotist’s perspective The neuropathic foot is one of the most challenging clinical scenarios that an orthotist can manage. The practitioner must not only perform a comprehensive examination of the client and formulate an individualized treatment plan including an appropriate orthotic modality but also provide the education required to achieve an appropriate clinical outcome. Failure to provide an appropriate intervention and necessary education may preclude successful treatment and further compromise the patient’s already delicate health condition. Preventative screening for these clinical problems is essential to identify those individuals who are most at risk. A common screening technique to assess for the presence of peripheral neuropathy is the Lower Extremity Amputation Prevention (LEAP) program.5,23 The five-step LEAP protocol includes the following: (1) an annual foot screening, (2) patient education, (3) daily self-inspection, (4) proper footwear selection, and (5) management of simple foot problems.5 The annual foot screening protocol of the LEAP program provides the orthotist with clinical information to help identify those patients who are at risk of ulceration. This protocol consists of two components: standardized questionnaire and protective sensation assessment. The questionnaire instrument assesses factors including history of ulceration, deformity, swelling, callous, muscle weakness, and the fit of the patients’ footwear. The protective sensation assessment is completed with a 5.07 gauge monofilament to assess the extent of sensory neuropathy. In patients who have already lost protective sensation, the US Health Resources and Service Administration recommends an increase in frequency for the administration of the screening exam to every 3 months given their increased relative risk.24 Completion of the LEAP screening protocol informs the patient’s orthotic treatment plan and will provide context for education about their condition and potential complications. Verbal and written patient education on the management of diabetes and associated neuropathy not only engages the patient but also may prevent further complications.25 Through the introduction of simple self-management techniques, the patient will assume responsibility for their health by performing daily skin inspections, identifying problems, and treating simple foot problems such as dry skin. Early recognition of potential problems empowers the patient to pursue them before they manifest into
something more serious. Patient education is not complete unless the orthotist also stresses the importance of appropriate footwear and the need to wear the footwear even for activities within the patient’s home.24 Once the neuropathic foot patient has been thoroughly assessed and educated about their condition such that they have been provided the information necessary to monitor their condition, the orthotist can begin to formulate a treatment plan. Orthotic management must account for internal influences such as bony malformation or ROM limitations, skin integrity, and the patient’s ability to implement the selected intervention independently. In patients with no active ulceration, long-term maintenance of the neuropathic foot is often achieved through the use of depth inlay shoes and multi-density accommodative foot orthoses. Chronic foot ulceration and/or active Charcot joint arthropathy requires more aggressive orthotic management such as joint immobilization and unweighting to promote initial healing. The objective of this section is to provide practitioners with a fundamental understanding of the orthoses commonly used to treat neuropathic foot and discuss their appropriateness for managing the neuropathic patient. A practice framework exists for the wound care practitioner to affectively treat neuropathic ulceration, but it is important to note that no single modality can address the needs of every patient. It is essential that the wound care practitioner create a multifaceted treatment plan to address each patient’s unique clinical presentation. Regardless of the chosen wound care modalities, it is the responsibility of the orthotics practitioner to work collaboratively to create an interface between the patient’s foot and the ground that can enable initial healing and long-term mobility for the patient with the neuropathic foot.
Diabetic shoes and multi-durometer foot orthoses Depth inlay footwear for the treatment of neuropathic foot is designed to provide prophylactic protection and longterm management to the at-risk neuropathic population. The goal of depth inlay shoes is to provide a total protective environment to the dorsal and plantar aspects of the foot, while allowing adequate internal volume to accommodate off-the-shelf or custom multi-durometer foot orthoses and prevent impingement of the patient’s anatomy. A proper fit between the shoe and the patient’s foot and a seamless construction on the inside of the shoe is intended to minimize shear and pressure within this interface. The addition of an extended shank or full-length carbon fiber insert reinforces the shoe and limits motion at the midfoot and forefoot during stance. Depth inlay footwear may be lace-up and/or Velcro closure depending on the patient’s dexterity and personal preference. Diabetic shoes may be further enhanced by pedorthic modifications to accommodate fixed deformities or address atypical
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Figure 2. (a) Forefoot and (b) hindfoot offloading footwear (OrthoWedge and HeelWedge; DARCO International, Huntington, WV, USA).
kinetics/kinematics. Common pedorthic modifications include the application of a medial or lateral flare, sole lift, or a rocker sole, which can be used to widen the patient’s base of support, address atypical joint moments, accommodate a leg-length discrepancy, or augment stance phase timing.8 The diabetic shoe is typically provided in conjunction with multi-durometer foot orthoses which utilize varying densities of materials to provide a total contact interface between the neuropathic foot and the shoe. Patients with neuropathic foot often sustain higher than normal peak plantar pressures,26 and a total contact environment reduces areas of peak pressure as a result of increasing the affected surface area. Multi-durometer foot orthoses are either off-the-shelf or custom in design and are selected based on presentation of the plantar foot. Patients with excessive callusing, ulceration, or foot deformity often require custom-fabricated foot orthoses due to their unique anatomy, while prophylactic care of mild foot abnormalities is achieved through the use of offthe-shelf foot orthoses.
Offloading footwear An important component to comprehensive wound care involves the minimization of pressure and/or sheer at the site of the wound, known as offloading. Even with optimal local wound care, debridement, and dressings, the wound is unlikely to heal without the addition of an offloading modality to the treatment plan. Offloading is challenging because many modalities reduce patient function, vocation, and safety due to their weight and bulk. Various styles of offloading footwear to relieve pressure sensitive areas of the neuropathic foot are commercially available. The style of offloading footwear is a function of the region of the foot that requires offloading. Offloading footwear is rarely a definitive intervention and
often used as an interim protective measure while custom orthoses are being fabricated. Offloading footwear is typically used as a provisional intervention as it may not facilitate the same level of healing observed when using other common modalities such as the total contact cast or removable cast walker.27 Offloading footwear often relies on aggressive modifications to the sole of the footwear to achieve its affect, but these modifications may negatively impact gait by creating discomfort28 and encouraging changes in joint moments and pelvic obliquity.29 Furthermore, the sole thickness of common offloading shoe orthoses is frequently higher than the patient’s typical footwear and may result in a leg-length discrepancy that requires consideration. Forefoot offloading footwear (Figure 2(a)) is designed to provide pressure reduction in the metatarsal heads and phalanges. This type of offloading footwear typically places the ankle in a relatively dorsiflexed position and effectively shortens the amount of relative time spent in the forefoot rocker during the stance phase of gait, thereby reducing the duration of applied pressure to this region. Hindfoot offloading footwear (Figure 2(b)) is designed to limit the magnitude of forces imparted on the calcaneus. This is done by removing the sole area plantar to the hindfoot which forces initial contact to occur anterior to the calcaneus. Not all offloading footwear requires the use of rocker modifications to impart a biomechanical benefit. Various manufacturers provide healing shoes that are offloading footwear to allow for targeted reduction in plantar pressures through the removal of pre-punched pads in the included insert (Figure 3). Care should be taken with this intervention as leaving a large void below an ulcerative site can cause wound compromise as the tissues of the foot can displace into the void during weight-bearing activity. However, a minimal level of plantar surface pressure
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Figure 3. Össur DH offloading insole (Össur Americas, Aliso Viejo, CA, USA).
applied to the ulcerative area can be maintained by backfilling the voids with a lower durometer material. A substantial body of literature on plantar wound treatment suggests that total contact casting (TCC) is the gold standard of offloading modalities.3 TCCs distribute pressure across the foot, immobilize the foot and ankle joints, and distribute forces across a larger surface area of the patient’s limb. TCCs are typically changed once per week to enable the wound care practitioner to monitor, cleanse, debride, and re-apply dressings to the wound. Should the patient have poor ankle brachial index, heavy necrosis, and/or an active infection, the TCC can be fabricated such that it is removable in nature enabling more frequent inspection and dressing changes. The dilemma with a removable design is that it enables patients to more easily/ readily doff the TCC, which can hinder compliance and potentially compromise healing. Rapid TCCs, which use off-the-shelf walking boots with pneumatic bladders to redistribute pressure, are becoming a popular offloading solution as they require minimal customization and fabrication time. However, rapid TCCs lack the total contact throughout the patient’s limb as they are not contoured to the patient’s unique anatomy. If a bivalved TCC or rapid TCC is used for treatment, the patient must clearly understand that walking even a few steps without the support of the device may compromise the wound healing process and potentially cause the development of new wounds.
Custom orthotic management Comprehensive orthotic management for patients with Charcot joint arthropathy, active ulceration, or moderateto-severe bony deformity cannot often be addressed with an off-the-shelf intervention. Custom orthoses allow the orthotist to utilize appropriate materials and design
principles for the individual patient’s needs. Commonly implemented custom orthotic modalities are the Charcot restraint orthotic walker (CROW) orthosis, patellar tendon-bearing (PTB) orthosis, and conventional ankle–foot orthosis (AFO) with molded calf lacer. The CROW orthosis is a custom-fabricated bivalve orthosis designed to provide total contact to the plantar aspect of the foot, ankle, and calf designed to treat Charcot joint arthropathy and diabetic foot ulcers. Given that the CROW is custom fabricated, it can accommodate a wide array of foot and ankle deformities often seen when treating the patient with neuropathic foot.30 The CROW orthosis is worn to provide offloading, tri-planar restriction motion of the foot and ankle. The CROW is contraindicated for patients with large volume fluctuation as these changes can compromise the fit and functionality of the orthosis. The ease of doffing of the CROW orthosis allows easy dressing changes and monitoring of the wound area. In practice, the CROW orthosis is used for long-term management of Charcot joint arthropathy and ulceration where a TCC or off-the-shelf intervention is inappropriate. A PTB orthosis is designed to provide offloading of the plantar aspect of the foot by suspending the limb via pressure tolerant structures around the knee, such as the patellar tendon (ligament), popliteal fossa, and medial tibial flare. The proximal portion is fabricated from a thermoplastic or thermoset material and is attached to a conventional AFO with alloy sidebars and double action joints. Depth inlay shoes with multi-density inserts are installed distally to provide total contact to the plantar aspect of the foot. This type of orthosis better accommodates volumetric changes than the CROW orthosis as its relatively open design can accommodate volumetric increase while a volumetric decrease is accommodated with the application of sock ply prior to donning the orthosis. The integration of double action joints enables the practitioner to tune the orthosis to optimize kinematics for the minimization of forces applied to the patient’s neuropathic limb.5 The conventional AFO with molded calf lacer is custom fabricated from a cast of the patient’s limb. The objective of this orthosis is to provide unloading of the plantar aspect of the patient’s foot by circumferential loading of the calf musculature.31 Similar to the PTB-style AFO, the conventional orthosis will accommodate volume fluctuation of the limb as the molded calf lacer can be adjusted circumferentially by simply loosening or cinching the closer while donning. The distal portion of the orthosis consists of alloy sidebars and double action joints to attach the orthosis to depth inlay footwear with a multi-density insert. The conventional AFO with molded calf lacer is an effective modality during acute, sub-acute, and long-term management of plantar ulceration. Regardless of the orthotic modality, the interdisciplinary care team must work closely to ensure the patient is phased into the appropriate intervention. Potentially
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Figure 4. (a) Wound on the lateral aspect of the patient’s left lower limb status post partial resection of the calcaneus and fifth metatarsal and (b) initial wound closure after the implementation of a PTB orthosis. PTB: patellar tendon bearing.
cumbersome interventions such as the CROW should be discontinued when the patient is a candidate for a less restrictive intervention such as custom shoes and inserts. Simply observing wound closure is not adequate justification as it takes 3 months for scar tissue to remodel and achieve 80% of its original tensile strength.32 Application of excess pressure on a recently closed wound from premature weaning into diabetic shoes could increase the risk for re-ulceration as the tissues have only 20% of its final tensile strength at 3 weeks following the scarring onset.
Clinical case study Patient history The patient was a 49-year-old female (165 cm, 102 kg) with type 2 diabetes, bilateral plantar sensory neuropathy, and type III Charcot joint arthropathy with a recently debrided diabetic foot ulcer on the right lower limb and a wound spanning the lateral aspect of the calcaneus, cuboid, and fifth metatarsal that was recently closed with a splitthickness skin graft. The patient stated that the ulcer on the right limb developed 7 months prior to the consultation and the Charcot joint arthropathy was diagnosed 10 months prior, although they stated that they were initially misdiagnosed with cellulitis. The wound on the left foot developed after the patient sustained a hematoma from striking their foot against the orthosis on the right foot, which eventually resulted in the need to perform a partial resection of the calcaneus and fifth metatarsal (Figure 4). The wound beds were clear and the edges were free from necrotic tissue. Previous orthotic management included an off-the-shelf pneumatic walking boot with a custom multi-density foot orthosis and a healing sandal with practitioner adjustable multi-density insole (Figure 3) on the right limb. The left lower limb had not been managed with an orthotic intervention and the patient utilized a kneeling scooter for
unweighting of the left foot skin graft area at the time of consultation.
Patient evaluation Hammer toes were observed bilaterally at digits 2–3 and the skin appeared to be dry and flaky with callous present on the plantar aspect of the calcaneus bilaterally and proximal to the Charcot joint at the midfoot of the right limb. The patient’s left foot presented in forefoot adduction likely due to changes associated with the recent osseous resections. A 5.07 gauge monofilament was used to assess for the presence of neuropathy, and findings were consistent with the presence of peripheral neuropathy as the patient could not identify the presence of the monofilament at any point on the plantar aspect of their foot. The patient’s lower limb passive ROM and strength were assessed bilaterally in a seated non-weight-bearing position. Both lower limbs were found to have hip and knee ROM within functional limits. Ankle ROM was assessed with the knee in terminal extension, and a plantar grade or neutral position was achieved bilaterally, but no additional dorsiflexion was available. Decreased mobility was noted at the midfoot joints bilaterally secondary to surgical intervention on the right limb and Charcot joint arthropathy on the left side. Bilateral manual muscle test findings revealed right–left symmetric muscle strength, with all lower extremity muscle groups demonstrating strength at a level of 4/5, apart from ankle dorsiflexor and plantar strength which were scored as 3/5.
Treatment Bilateral impressions were taken in a non-weight-bearing position with the knees in terminal extension to better reflect ankle alignment during ambulation for the fabrication of bilateral CROW orthoses. The positive model was rectified with 3-mm build-ups placed over the Charcot joint
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at the midfoot of the right limb and the skin graft over the lateral aspect of the foot on the left limb. The orthoses were fabricated from 3/16″ copolymer with a soft-density polyethylene foam liner and removable multi-durometer insole. The reliefs were back-filled with pink Plastazote (Algeos USA, Santa Monica, CA, USA) to restore total contact with the limb and then covered with ShearBan (Tamarack Habilitation Technologies Inc., Blaine, MN, USA) to minimize friction over the compromised areas. A rocker bottom sole was fabricated from crepe to enable adjustments to the rocker profile and height during the fitting process.
Follow-up The patient was closely followed with bi-monthly visits to the orthotics team and wound care specialist over a 6-month period of time. Adjustments were made to the CROW boots to maintain total contact throughout the patient’s lower limbs due to volumetric or anatomical contour changes. The wound on the plantar aspect of the right foot was healed during the 6 months of immobilization in the CROW. The wound on the lateral aspect of the foot increased in diameter and was migrating over the foot perimeter to the plantar aspect. This was further compromised by excessive wound exudate which resulted in skin maceration and the need for increased frequency of dressing changes.
Figure 5. Side view of the leather unweighting orthosis.
Conclusion Secondary treatment Six months after the CROW orthoses were provided, the clinical team decided to transition the patient into bilateral leather unweighting orthoses attached to a conventional AFO with alloy sidebars and double action joints locked at 90° (Figure 5). The AFOs were attached to a pair of custom-made shoes, and the patient was instructed to wear the AFOs full time during weight-bearing activity. After 3 months of management with the unweighting orthoses, the right plantar wound remained healed, but the wound on the left foot demonstrated minimal improvement. The left foot wound had deepened in the area of the base of fifth metatarsal and forcing the patient’s vascular surgeon to pursue the removal of the base of the fifth metatarsal to better facilitate wound healing. The leather unweighting AFOs were used full time for ambulation after the resection of the base of the fifth metatarsal in conjunction with continued wound debridement and dressing changes. The wound on the lateral aspect of the left foot closed 7 months after the resection of the base of the fifth metatarsal. The patient continued to utilize the conventional AFOs with molded calf lacers after the successful wound closure in order for the scar tissue to maturate and continue to remodel with type I collagen fibers.
The clinical management of the neuropathic foot requires careful consideration of each patient’s unique needs to effectively address the systemic and local issues for ensuring successful intervention. Effective management facilitates wound healing and prevention to avert further complications and subsequent amputation. Given the multifactorial nature of the pathology, there is no single model for interdisciplinary care. However, a collaborative effort between relevant healthcare providers may positively affect the patient’s health status while lowering associated costs under certain circumstances. Acknowledgements The ideas presented in this article would not have been possible without the insights of and discussions with colleagues Marty Carlson, MS, CPO, and Wieland Kaphingst, Dipl.-Ing., CPO, FAAOP.
Author contribution All authors contributed equally in the preparation of this manuscript.
Declaration of conflicting interests Charles Kuffel is a paid consultant of Tamarack Habilitation Technologies Inc. (Blaine, MN, USA).
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Robinson et al. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
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