In the previous issue of WCHM, Part 4A in the Diabetic Wound Prevention series provided detailed descriptions of shoe characteristics and sock components along with various types of protective footwear, ranging from quality athletic walking shoes to Charcot restraint orthotic walker (CROW) boots. Now, in Part 4B, we continue to expound on protective footwear as an essential component for the prevention of new and recurrent wounds by addressing some common misconceptions and discussing custom foot orthotics and total contact casting (TCC). In addition, this article details the Medicare “Therapeutic Shoe Bill” and highlights a few challenging situations in which protective footwear may be insufficient and surgery and other interventions may be necessary.
Making Sense of Orthotics
Orthotic considerations. In the previous section, orthotics were mentioned as a prescription item added to off-the-shelf footwear to control alignment of the feet and ankles. Simply stated, orthotics are devices that improve or straighten the alignment of body parts. They can be as simple as a heel pad added to a shoe or as complicated as a total-control lower-extremity brace.
Orthotics play an important role in prescription footwear because deformities are frequently a precursor to foot wounds. Many patients with feet that are at risk for wounds have deformities. The three largest user groups for orthotics are children with foot concerns articulated by their parents, athletes and others who experience foot pain with activities, and patients who have neurological impairments (especially patients with diabetes).
Much confusion exists as to what orthotics do and when they are needed (Figure 9).8 The consequences of this are overutilization, inappropriate applications, and needless expenditures for these devices. The following information discusses seven misconceptions and/or fallacies pertaining to orthotics. The goals are twofold: to make sense out of their use and to delineate their indications for foot conditions at risk for wounds (Table 3). Indications for prescribing and using orthotics are different for those patients with risk factors for developing wounds (deformity, previous amputation, previous wound, peripheral artery disease and/ or neuropathy) versus those using orthotics to manage symptoms that are associated with walking and running.
FIGURE 9. Fallacies and responses regarding
Legend: Generalizations about prescribing and using othotics are different for those patients with risk factors for developing wounds versus those using orthotics to manage pain symptoms (usually with activities).
|Problems||Type/How Manifested*||Orthotic Management|
|Location: Primary the Forefoot|
Planar/Static with dynamic
Straight or reverse last shoes
Lateral heel +/- medical sole wedges; pronator pads (all of questionably benefit; usually improves spontaneously with time)
(Out-toeing—abduction, "skew" foot)
|Same as above (SAA)||Medial heel and/or lateral sole wedges; pronator pads (all questionably effective)|
(Mallet, hammer, claw, angulated or rotatory)
|Most are planar & static with dynamic components||Toe separators, lambs wool between toes, shoes with large toe boxes|
|Non-planar/Static with dynamic components||Lateral forefoot wedges for inserts and or soles of shoes; if due to Charcot neuroarthropathy, consider CROW (Charcot restraint orthotic walker) boot|
|SAA||Medical forefoot and/or sole wedges|
|Location: Primarily the Midfoot (Arch portion of the foot)|
|Planar/Dynamic, but accentuated with loading||Arch supports; if asymptomatic, leave untreated|
|Hyperpronation||Usually with hindfoot valgus + flat feet||Custom molded arch supports with medial heel wedges|
(Abnormally high arches)
|Planar/Static||Custom molded arch supports supplemented with forefoot and heel pressure relief pads|
|Congenital vertical talus||SAA||Custom shoes; generally not manageable with footwear and orthotics; surgery usually required|
|Location: Primarily the Hindfoot (Heel portion of the foot) and Ankle|
(Inward tilting, supination)
|Non-planar/Static||Lateral heel wedges; frequently in association with forefoot and midfoot supination management|
(Outward tilting, pronation)
|SAA||Medial heel wedges; usually in conjunction with midfoot hyperpronation management|
|Equinus contracture||Planar, non-planar (with hindfoot varus/Static||Heel lifts; Klenzak brace; management of heel varus; Frequently Achilles tendon lengthening required|
|Location: Combinations (Involvement of 2 or more foot & ankle components)|
(Heel varus, forefoot adduction + ankle equinus)
|Non-planar/Static||Casting, Achilles tendon lengthening; custom orthotics as needed|
|Charcot arthropathy||SAA||The apex of the hierarchy of prescription footwear; see Figures 2 through 8|
Zig zag (skewfoot)
(plantar deformities in 2 or more directions)
|Planar/Static||Custom molded shoes; surgery|
Notes: *Type refers to plane of the foot; planar indicates it is flat, while non-planar means it is tilited (e.g. varus vs valgus; pronation vs supination; inversion vs eversion, etc.)
How manifested refers to whether it is Static, that is the deformity is presented when the foot is un-loaded or Dynamic that it occurs with loading, muscle contraction and/or walking.
Misconception 1: A minimal discrepancy or deformity — for example, mild flattening of the feet or tilting of the heels — never needs an orthotic.
Fact: The answer to this question is tricky. If the problem causes symptoms—for example, pain, stiffness, soreness, swelling, etc. with activities or signs of irritation of the skin are observed at the deformity site — it should be managed with orthotics (or other offloading techniques). The question is tricky because if the person can do the activity without symptoms, as is often the case in athletes or children, orthotics are not needed. If the foot is at risk for wound formation, however, everything possible, including orthotics (and other offloading measures), should be done to prevent a wound from developing due to the multiplier effect of repetitive sub threshold (i.e., below the severity to generate an acute ulceration, but enough to generate erythema, callus formation and/or pain) stresses.
Misconception 2: There is little objectivity in deciding what situations require an orthotic.
Fact: Objectivity in prescribing orthotics is afforded by pairing the patient’s symptoms with the following signs:
- Imbalances refer to alterations in muscle control that lead to abnormal the antagonist muscles’ activities. Diabetes, nerve injuries/spinal cord injuries, strokes, Parkinsonism and hereditary conditions are the most frequent causes of muscle imbalances. With time, contractures arise and joints become permanently deformed.
Contractures arise in joints when imbalances persist or joints are positioned in the wrong position for sustained periods, such as with casting. Joint stiffness and decreased range of motion are findings associated with contractures. A joint contracture is defined when the loss of motion becomes fixed — for example, an equinus contracture from shortening of the Achilles (calf) tendon/muscle group. When this occurs, the ankle can no longer be brought to the neutral position.
Deformities are structural changes in the anatomy of the foot and ankle such as bunions, Charcot of bone (e.g., spurs, malalignments after fractures, congenital anomalies, collapses associated with Charcot neuroarthropathy, etc.). Many deformities are amenable to management with orthotics as will be described in the third misconception in this section neuroarthropathies, forefoot adductus, hindfoot varus or depressed metatarsal heads (the precursor of forefoot malperforans ulcers). Deformities arise from muscle imbalances as observed with clawing of toes, loss of ligament support, bony overgrowth from repetitive pressure/shearing stresses, structural abnormalities, collapses associated with Charcot neuroarthropathy, etc.). Many deformities are amenable to management with orthotics as will be described in the third misconception in this section.
When orthotic selection is addressed from these three perspectives, logical decisions become obvious. When sensation is absent, as is so frequently observed in patients with problem wounds, the decision for orthotic selection is made from the above signs. When these problems are not manageable by orthotics, then surgical interventions, many of which are minimally invasive and can be done in the office setting are needed. This is in contrast to athletes where pain symptoms are the indication for obtaining orthotics.
Misconception 3: So many deformities can occur in the foot and/or ankle that it is difficult to make decisions as to what orthotic is appropriate.
Fact: Although more than a dozen deformities may be ascribed to the foot, they can be readily understood if considered from the following elements (Table 3): 1) location (forefoot including toes, midfoot, hindfoot or combinations), 2) type (such as primarily a) planar — the foot remains flat such as with abduction, adduction and equinus) or b) nonplanar — the normal flat surface of the foot is tilted as observed in hyperpronation-eversion- valgus or supination-inversion-varus deformities), and 3) how manifested (dynamic implies that the problem occurs with activity whereas static means the problem is fixed and present whether at rest or with activity). Each problem may be due to a single element or compound — that is, consisting of two or more of the above elements.
Misconception 4: Foot deformities invariably worsen with time; hence orthotics should be used as soon as a problem is recognized.
Fact: Judgment is essential for making decisions about when to prescribe orthotics. The majority of foot deformities in children such as in- toeing, flat feet, and toe walking resolve spontaneously as the child matures. In the presence of neurological impairments (e.g., cerebral palsy, myelodysplasia, polio, etc.), spontaneous correction is not likely to occur. Orthotics and/or surgical interventions should be utilized early to prevent worsening deformities.
For adults with asymptomatic, nonprogressing deformities, orthotics are not indicated. For adults who develop new deformities such as hyperpronation of the midfoot (e.g., secondary to posterior tibial tendon dysfunction), especially those with risk factors for developing foot wounds, orthotics and protective footwear are indicated as soon as the problem is recognized. The goals are to prevent the deformity from progressing and/or the development of wounds that could require surgery in the future.
Misconception 5: Shoe comfort and wear patterns are nonreliable indicators of the need for orthotics.
Fact: Shoe comfort and wear patterns provide important clues for decision making about orthotic selection. In the normal foot, shoe wear is first noted along the lateral edge of the heel and the center portion of the toeward end of the sole. As the shoe wears, the upper materials may stretch to accommodate a deformity, and in the absence of sensation, the patient may not complain of pain in the shoe as it is stretched out.
Obviously pressure areas are deforming the shoe and can evolve to ulcerations at the deformity site. If the shoe is uncomfortable, explanations are needed and proper adjustments made. Shoe- wear patterns also provide helpful information. For example, if the upper, medial portion of the sole of the shoe has excessive wear, pronation (eversion) is usually the explanation. Excessive medial heel shoe wear indicates excessive hindfoot valgus. These problems need to be recognized and managed with orthotics if the patient has risk factors for developing foot and ankle wounds and/or the deformities are a source of pain.
Misconception 6: If orthotics are indicated, they need to be customized.
Fact: Many conditions for which orthotics are indicated can be managed by simple corrections such as adding a padded insert, an off-the-shelf metatarsal pad, a heel pad, a toe separator, a donut pad or similar devices.9 Many of the padded inserts have additional features such as padding to counteract pronation and gel inserts to provide extra heel or forefoot padding. The off-the- shelf devices usually cost a fraction of custom-molded orthotics. If they relieve symptoms and offload pressure areas, more costly customized orthotics are not indicated. Two guidelines are recommended for prescribing custom- molded orthotics: First, in patients with normal foot sensation, they should be obtained after a trial of less-expensive off-the-shelf versions have been tried, but the off-the-shelf choices provide only partial or no relief of symptoms. Second, in patients with sensory neuropathy and associated deformities, prescription orthotics and footwear are usually indicated even without a trial of off-the-shelf devices.
Misconception 7: If orthotics are obtained, they need to be utilized 100 percent of the time with footwear.
Fact: For patients with normal sensation, orthotics may need to be used only for repetitive stress activities such as running. Running activities multiply and replicate the stresses through the feet more than three times the person’s body weight, somewhat analogous to driving a nail into a board. If symptoms are not noted with standing or walking, orthotics need not be used for these activities. In patients subject to foot or ankle ulcerations because of sensory neuropathy or other risk factors for wounds, the orthotic is used to prevent a wound from occurring and consequently should be utilized with all standing and walking activity.
In summary, the decision to prescribe orthotics should be based on the patient’s complaints, the problems (e.g., muscle imbalances, contractures or deformities) found during the exam and what is the most cost-effective way of managing it. For patients with normal sensation, many orthotic requirements can be met with off-the- shelf devices. Custom-made orthotics should be prescribed by physicians familiar with the evaluation, management and prevention of foot and ankle problems and obtained through pedorthotists and podiatrists familiar with the options and available applications. In patients with neurological impairments, associated deformities and the other risk factors for foot and ankle wound occurrence, custom-prescribed orthotics and protective footwear are advised because this is the at-risk group for developing problems.
Total Contact Casting (TCC)
Although total contact casts (TCC) have been considered the gold standard for offloading, recurrence rates with TCC after healing and compliant use of protective footwear approach 50 percent.10 TCC is often recommended for outpatient management of diabetic foot ulcers, especially in forefoot locations; these ulcers, however, typically occur because of underlying deformities. When the ulcers occur in the midfoot and hindfoot, and especially if hospital management is required to manage the deformity, TCC is usually not sufficient and surgery is required.
Historically, there is an extremely low use rate by clinicians and poor patient tolerance due to logistical purposes. First, the cast usually must be removed if the provider wants to examine or treat the wound; and the process of placing the TCC is quite time-consuming (Table 4). Second, it is not recommended for patients with underlying bony infection, deep sinus tracts, large draining wounds, dermatitis, excessive edema, severe peripheral arterial insufficiency, and "cast claustrophobia."
TABLE 4. Total contact casting application
Inappropriate Use of Protective Footwear
In some situations, protective footwear will not provide adequate offloading. The wound care provider must appreciate this and not persist with new and/or alterations of the patient’s protective footwear in hopes of achieving a solution while the wound deteriorates and/or recurs. In such situations surgery and other interventions become necessary. In many situations, the causes are multifactorial, and the solutions require more than one intervention. In almost all cases after interventions, properly prescribed protective footwear is required. Consider the following challenges and their solutions:
1. Challenge: Progressively worsening deformity such as a subluxing ankle joint with increasing angulation and impending breakdown of skin over the apex (e.g., the lateral malleolus) of the deformity (Figure 10) Solution: Osteotomy to realign ankle and intramedullary ankle rodding or temporary external fixation with the ankle in the reduced position. Extremity shortening secondary to the osteotomy should be equalized with shoe lifts.
FIGURE 10. Deformity where protective footwear becomes inadequate
Legend: Severe deformity with infected lateral malleolus exceeds the ability of a CROW boot or total contact casting to manage. Surgical realignment or below knee amputation become the options.
2. Challenge: Protruding bone or bony prominence at the base of an ulcer that has not improved with offloading Solution: Exploration and debridement of bony prominence (i.e. ostectomy), reactive bursa and cicatrix formation surrounding the deformity.
3. Challenge: Recurrences of a malperforans ulcer under a metatarsal head after healing with total contact casting and use of protective footwear Solution: Realignment of metatarsal head with simple percutaneous scoring of the metatarsal at the neck level and osteoclasis to direct the metatarsal head dorsally. A Weil osteotomy is also an option but is more invasive and requires internal fixation.
4. Challenge: Hindfoot ulcer with loss of heel foot pad and boney prominence in base of wound without an ankle dorsiflexion contracture (i.e., muscle imbalance with loss of gastrosoleus muscle strength) Solution: Partial calcanectomy with ankle fusion or release of ankle dorsiflexors
5. Challenge: Flail midfoot with severe destruction of midfoot bones secondary to Charcot neuroarthropathy Solution: Resect nonfunctional midfoot bones to shorten foot length with or without bone grafting
6. Challenge: Claudication with rest pain regardless of footwear Solution: Lower-limb
7. Challenge: Severe equinus contracture with plantar surface pressure sores at the tips of the toes Solution: Achilles tendon lengthening
8. Challenge: Morbid obesity and/or massive lymphedema Solution: Edema control, weight reduction including surgical techniques, wheelchair ambulation
9. Challenge: Dry, scaly atrophic plantar forefoot and heel fat pads Solution: Daily skin cleansing and lubrication; optimal shoe padding and fit.
10. Challenge: Abnormal, excessive shear forces with walking secondary to muscle imbalances, weaknesses or deficiencies secondary to neurological conditions or trauma Solution: Physical therapy and gait training; orthotics to mitigate deformities; walking aids from cane to motorized wheelchair.
In some situations, ambulation needs to be restricted or almost totally avoided to prevent new or recurrent foot wounds regardless of the interventions. Fortunately, other options for mobility exist, such as wheelchairs and motorized scooters/wheelchairs. When such assistive devices are prescribed, it should not be considered a failure of protective footwear or management but rather insight to the total needs of the patient.
Medicare Therapeutic Footwear Benefits
Therapeutic Shoe Bill. It is no coincidence that Medicare (Center for Medicare/Medicaid Services) provides funding for diabetic footwear. In 1993 the Therapeutic Shoe Bill (TSB) benefit became a Medicare entitlement for diabetic patients.11 This policy exemplifies the goals of preventative medicine. It provides a mechanism for diabetic patients with risk factors for developing foot wounds to obtain protective footwear. Most significantly, this benefit is proactive (in contrast to many of the other Medicare entitlements), as it provides a means to prevent a problem from occurring rather than the much more expensive alternative of treating it after it has already arisen.
This entitlement provides tangible benefits with protective footwear rather than only education, as in smoking-prevention, need for exercise and weight-reduction programs.
Stipulations of the Therapeutic Shoe Bill.
The TSB benefit has several stipulations: First, the beneficiary must have Medicare Part-B (physician services) coverage. Second, a signed certificate of medical necessity (CMN) is needed from the prescribing physician that therapeutic footwear is required; the CMN should include the following four affidavits:
- The patient has diabetes mellitus
The patient has one or more of the following conditions involving either foot:
—history of partial or complete amputation of the foot
—history of previous foot ulceration
—history of preulcerative callus
—peripheral neuropathy with evidence of callus
The prescribing physician is treating the patient under a comprehensive plan of care for his/her diabetes
The patient needs special shoes (extra depth orcustom-molded shoes), inserts or modifications because of his/her diabetes
Third, the prescription for therapeutic footwear is written by a qualified physician, that is someone knowledgeable about protective footwear and inserts. Finally, the therapeutic footwear must be supplied by a pedorthotist, other qualified individual, or a retail store that sells footwear approved by the TSB.
Replacements and costs. Medicare therapeutic footwear benefits are provided yearly. In a given calendar year, Medicare will cover 80% of the allowed amounts for one of the following:
- One pair of off-the-shelf extra-depth shoes plus three pairs of multidensity inserts
- One pair of off-the-shelf extra-depth shoes including modifications (such as fillers, lifts, wedges, relief for pressure areas, etc.) plus two pairs of multidensity inserts
- One pair of custom-molded shoes plus two pairs of multidensity inserts each year
It is important to note that the TSB is not a program intended to provide shoes for all diabetics, but its primary goal is to prevent ulcerations/ amputations in the at-risk patient.
By the footwear/insert provider accepting assignment, it is understood that the charges for the protective footwear will conform to what Medicare considers reasonable and customary.
Alternatives to the Therapeutic Shoe Bill. Although the Medicare TSB applies specifically to diabetic patients, are there other alternatives for patients with problem wounds or risk factors for developing problem wounds who do not have Medicare Part-B benefits? The answer is a somewhat qualified yes. Many state Medicaid programs have provisions that parallel the Medicare guidelines. Private insurance companies may or may not have provisions for protective footwear. If the footwear is indicated, however, a “letter of petition” by the prescribing physician to the insurance carrier describing the problem and the justification and the predicted cost-benefits for protective footwear is often sufficient to reimbursement for the footwear. A third alternative is for the patient to pay for the protective footwear/inserts himself/herself. Many times, charges for similar items vary considerably from one supplier to another and/or discounts are given for paying cash.
For nonwound prevention considerations, such as pain relief with running, the patient may have to pay for the custom orthotics out of pocket. Finally, less costly alternatives such as using lambswool for fillers and toe separators, off-the-shelf inserts, shoes with built-in pronation inserts, casts, etc., can be used as an interim measure when it is not possible to obtain custom protective footwear.
Do’s and Don’ts Pertaining to Protective Footwear
Do’s with respect to protective footwear:
Wear appropriate footwear for your foot and ankle problems.
Frequently check shoes and orthotics for signs of wear poor fit.
Don’ts to prevent new or recurrent foot wounds
Don’t walk barefooted (use protective footwear at all times when out of bed).
Don't assume a new pair of shoes, even if provided from a footwear prescription, will fit perfectly. “Break them in” slowly, initially wearing the shoes for only for a few minutes at a time and then removing them to inspect the skin for pressure areas or signs of rubbing.
Don’t wear inappropriate shoes for fashion reasons or because they feel comfortable (such as house shoes and slippers without appropriate support).
The selection of protective footwear is both an art and a science. The science is reflected by the wealth of information available about the components of footwear, the variety of choices available for protective footwear and orthotics and the ability to confirm by examination and imaging studies what the structural problems are. The selection of protective footwear is also an art. Decisions have to be made as to what level of the protective footwear hierarchy is appropriate for the patient. Foot and ankle problems are frequently unique and require individual modifications for the shoe. Foot problems change, so what is appropriate initially may require alterations in the future.
It is obvious that “If the shoe fits, don’t always wear it.” This has several implications. First, patients may prefer to wear their old, worn, deformed shoes because they feel so comfortable instead of their new or replacement footwear.
Second, newly prescribed footwear often requires modifications to fit properly. The more complicated the problem, the more likely modifications will be required. In our experiences, about 50 percent of the footwear prescriptions we write require additional modifications by the pedorthotist or certified footwear provider as the patient begins to use the footwear.
Third, there may be delays in patients’ appreciation of new foot and ankle problems with their new footwear due to sensory neuropathy. Fourth, patients with risk factors for developing foot and ankle wounds often have ongoing, progressively worsening deformities, peripheral artery disease and neuropathy. The changes associated with these may require expedient revisions in footwear and/or surgical interventions.
Listen to the patients, and hear what they like about their old shoes and what they do not like about their new protective footwear. Then pair this information with the science that is needed to meet their prescription footwear needs. As stated previously, protective footwear is the second line of defense (after skin and toenail care) for preventing problems in patients with risk factors for foot and ankle wound formation. If protective footwear is appropriately prescribed and the patient is instructed in the philosophy behind the quotation “If the shoe fits, don’t always wear it,” new wound problems can usually be prevented. When protective footwear cannot accomplish these goals, then surgery, the first line of offense, may be required.
1. Cavanagh PR, Owings TM. Nonsurgical strategies for healing and preventing recurrence of diabetic foot ulcers. Foot Ankle Clin. 2006; 11(4):735-743.
2. Strauss MB, Miller SS. Diabetic Foot Problems: Keys to effective, Aggressive Prevention. Consultant 2007; March: 245-25.
3. Sugarman JR, Reiber GE, Baumgardner G, et al. Use of the therapeutic footwear benefit among diabetic Medicare beneficiaries in three states. Diabetes Care. 1998; 21:777-781.
4. Wooldridge J, Moreno L. Evaluation of the costs to Medicare of covering therapeutic shoes for diabetic patients. DiabetesCare. 1994; 17:541-547.
5. Paton J, Jones RB, Stenhouse E, Bruce G. The physical characteristics of materials used in the manufacture of orthoses for patients with diabetes. Foot Ankle Int. 2007: 28(10):1057-1063.
6. Hastings MK, Mueller MJ, Pilgram TK, et al. Effect of metatarsal pad placement on plantar pressure in people with diabetes mellitus and peripheral neuropathy. Foot Ankle Int. 2007; 28(1):84-88.
7. Brown D, Wertsch JJ, Harris GF, et al. Effect of rocker soles on plantar pressures. Arch Phys Med Rehabil. 2004; 85(1):81-86.
8. Janisse DJ, Janisse E. Shoe modification and the use of orthoses in the treatment of and ankle pathology. J Am Acad Orthop Surg. 2008; 16(3):152-158.
9. Groner C. Orthosis Symbiosis: Clinicians are finding a middle ground in the debate over custom versus prefab foot orthoses. BioMechanics. 2005, 12(5):22-23.
10. Frigg A, Pagenstert G, Schafer D, et al. Recurrence and prevention of diabetic foot ulcers and total contact casting. Foot Ankle Int. 2007 Jan; 28(1):64-69.
11. Janissee DJ. The Therapeutic Shoe Bill: Medicare coverage for prescription footwear for diabetic patients. Foot Ankle Int. 2005; 26(1):42-45.