The Preservation Amputation Care and Treatment (PACT) program in Nashville decreased amputation rates by 40% in patients with diabetes. Here’s how they did it.
By Mark Hinkes, DPM
Clinicians who treat the lower extremity know that of all the pathology that can affect it, few medical problems present more challenge, are more complex, cause more damage and result in wounds more difficult to heal than those caused by the co-morbidities of diabetes. Chronically elevated blood glucose levels are responsible for the processes that impair the neurological, vascular, and immune systems, which can result in a variety of medical problems to the lower extremity of the patient with diabetes.
When it comes to the foot and leg, we know with almost 100% certainty how they will be affected by diabetes. Diabetic neuropathy and its three subcategories — autonomic neuropathy, sensory neuropathy and motor neuropathy — can leave the lower extremity vulnerable to silent or painless trauma. That is the triggering event that can ultimately lead to lower extremity amputation. A compromised circulatory system fails to bring enough fresh oxygenated blood, nutrients, and antibiotics to a traumatic wound, and the immune system cannot resolve an infection by fighting bacteria and cleansing the wound site on a cellular level.
The results are tragic. In the United States, infected foot ulcers are the most frequent admitting diagnosis for hospitalization of patients with diabetes. In 2003, there were about 111,000 hospital discharges for lower extremity ulcers.1 There are more than 90,000 lower extremity amputation procedures performed on patients with diabetes in the U.S. annually, which equates to one every six minutes.2 Worldwide, there are more than 1 million amputation procedures performed each year, at the rate of one every 30 seconds.3 Diabetes mellitus and its complications are the sixth leading cause of death in the United States.4
Problems affecting the lower extremity are complex and respond best when treated by a multidisciplinary team of medical specialists. These specialists may include: endocrinologists, neurologists, diabetes educators, vascular surgeons, orthopedic surgeons, podiatrists, nurses, pharmacists, infectious disease specialists, wound care specialists, nutritionists, and specialists in prosthetic and orthotic services, physical medicine and rehabilitation. Comprehensive foot care programs can reduce amputation rates by 45% to 85%.5
As the complexity and severity of problems involving the foot and leg increase, so do the costs of treating them.5 The total annual economic cost of diabetes in 2007 was estimated to be $174 billion. Medical expenditures totaled $116 billion: $27 billion for diabetes care, $58 billion for chronic diabetes-related complications, and $31 billion for excess general medical costs. Inpatient hospital care costs totaled $58.3 billion, not including $9.9 billion spent on physicians’ office visits, directly attributed to diabetes. Diabetes-related hospitalizations totaled 24.3 million days in 2007, an increase of 7.4 million from the 16.9 million days in 2002. The average cost for a hospital inpatient day due to diabetes is $1,853 and $2,281 due to diabetes-related chronic complications, including neurological, peripheral vascular, cardiovascular, renal, metabolic, and ophthalmic complications.
The direct cost of an amputation associated with the diabetic foot is estimated to be between $30,000 and $60,000. Three years of subsequent care for individuals whose ulcer has healed without the need for amputation has been estimated to cost between $16,000 and $27,000. The corresponding cost for someone who eventually needs an amputation ranges from $43,000 to $63,000, mainly due to the increased need for home care and social services.6
According to the National Institute of Diabetes and Digestive and Kidney Diseases, an average of 54,000 diabetic amputations were performed each year between 1989 and 1992. National Hospital Discharge Survey data for 1996 indicated that 86,000 people with diabetes underwent one or more lower-extremity amputations.7 The total annual cost for these amputations was more than $1.1 billion dollars, excluding surgeons’ fees, rehabilitation costs, prostheses, time lost from work, and disability payments.8 Furthermore, in a 1995 study, the average individual cost of a minor amputation averaged $43,000; a major amputation cost $65,000.9
The mortality rate after amputations is about 40% at one year10 and 80% at five years.11 Five-year mortality rates after new-onset diabetic ulceration are between 43% and 55% and up to 74% for patients with lower-extremity amputation. These rates are higher than those for several types of cancer including prostate, breast, colon, and Hodgkin’s disease.12
Identifying the opportunity
The bright side to these grim statistics is a unique opportunity to impact the quality of life and health care costs for diabetic patients through a dedicated prevention program. By identifying each patient’s individual risk factors for amputation based on his or her co-morbidities, a personalized prevention plan can be formulated. The goal is to prevent a triggering event of mechanical, chemical, or thermal trauma to the foot or leg that can lead to a lower extremity amputation. Recent estimates indicate that up to 85% of all lower extremity amputations can be prevented.13
At the Veterans Affairs Medical Center in Nashville, the Preservation Amputation Care and Treatment (PACT) program has demonstrated a 40% decrease in the number of lower extremity amputations over the past five years. The program has decreased the costs of pharmaceuticals by 48%, lab studies by 32%, and inpatient bed days by 44%. The total cost savings is a remarkable $1.8 million.14
Examination and evaluation of the patient with diabetes, with a focus on the lower extremity, is the first step in identifying the patient’s risk factors and preventing lower extremity amputations. In many countries, including the United States, there is a lack of both information and training about this subject.15-17 Although information is available in the medical literature on the proper methods for performing a risk evaluation of the lower extremity, that information is not organized, standardized, universally understood, or appropriately implemented.18-26
The fundamental issues in performing a valid foot exam and lower extremity evaluation for amputation prevention include:
- Testing: what to test and how to test it
- Identifying and overcoming testing pitfalls
- Understanding tester and testee bias
- Recording test results appropriately
- Creating an amputation prevention program based on identified risk factors
The three core parameters to be tested in a valid foot ulcer and leg amputation prevention exam include: vascular testing through the evaluation of pedal pulses; neurological testing to assess loss of protective sensation (LOPS), determined by the monofilament test; and deformity identification with regard to the bones, soft tissues and toenails.
Findings of diminished or absent pulses, pallor on elevation, dependent rubor of the foot on lowering of the leg, delayed digital capillary return, and thickened nails, lack of hair on the digits or cool skin temperature at the toes are consistent with impaired arterial foot circulation. There is some confusion about the relationship between foot pulses and the ulcers that can lead to amputation. Many practitioners feel that inadequate arterial circulation, evidenced by absent foot pulses, is the cause of foot ulcers that lead to amputation. On the contrary, the event that causes the foot ulceration is actually silent or painless trauma of mechanical, chemical or thermal origin. The lack of adequate circulation is the co-morbidity that contributes to failure of such ulcers to heal, uncontrollable infections, and gangrene—all of which can lead to amputation.27-29
The two pulses to be evaluated on each foot are the dorsalis pedis (DP) and the posterior tibial (PT) pulses. Palpating a foot pulse is a skill that takes time for a practitioner to develop. The key issue is the amount of finger pressure that the examiner applies against the artery when palpating. Too much pressure may occlude the artery, causing the examiner to believe that the pulse is weak or missing. Not enough pressure may cause an examiner to miss a pulse. The examiner must be sure he is not reporting his own pulse instead of the patient’s pulse.
The dorsalis pedis artery is located between the first and second metatarsals on the dorsal aspect of the foot.(Figure 1) Some patients may not have palpable pulses in their feet. In that case, a congenital absence of the DP artery should be considered. It is absent, unilaterally or bilaterally, in 2% to 3% of young healthy individuals.30
The posterior tibial artery runs behind the medial aspect of the ankle bone at the distal end of the tibia.(Figure 2)
Traditionally, pulses are graded from 0 to 3. There are differences in how practitioners perceive and grade foot pulses. I use a system of narrative description– Absent, Barely Palpable, Palpable, and Bounding — to report pulses. This narrative style helps me better understand the patient’s vascular condition and eliminates any ambiguity of grading and reporting the pulses in the number system.
When not all pulses are readily palpable, I locate one palpable pulse of the four to be checked. I keep my hand on that pulse while I palpate the other pulse locations with the other hand. The already identified pulse gives me the baseline rate and rhythm of the pulse, so that the other three pulses can be more easily identified.
If inadequate circulation is identified in the foot based on physical exam and/or history of claudication, pain at rest, delayed or nonhealing wounds or any of the other signs mentioned above, the patient should be referred for vascular testing. The two most common screening procedures include ABI (ankle-brachial index) testing and ABI testing with segmental pressures. Other tests that may be considered if surgery is being contemplated include duplex Doppler evaluation and an arteriogram.31-33
The monofilament test for evaluating loss of protective sensation is the gold standard for identifying patients at risk for lower extremity amputation. Almost 30% of people with diabetes aged 40 years or older have impaired sensation in the feet (i.e., at least one area that lacks feeling).5 Research indicates that the monofilament testing device is an inexpensive, reliable and easy to use clinical indicator for identifying patients who are at risk for developing foot ulcers and subsequent amputations.10,29,34,35 Those patients unable to sense the 5.07 wire on any part of their foot should be prescribed preventive care. This should include ongoing professional foot care when necessary, patient education, and appropriate insoles and/or footwear.
There has always been controversy about how to perform this test properly: how to touch the foot, where to touch and where not to touch the foot, and what constitutes a valid monofilament exam. Since this exam provides the most critical information in the decision-making process for care, it must be performed, documented, and interpreted correctly in order for a practitioner to identify a patient’s risk factors and prescribe the most appropriate preventive care plan.
In my practice, I touch the monofilament to three specific sites to evaluate for loss of protective sensation and the possibility of neuropathic ulcers: plantar to the great toe, plantar to the first metatarsal, and plantar to the fifth metatarsal. These areas evaluate the L-4 and S-1 dermatomes. Touching plantar to the third metatarsal head or the distal portion of the fourth toe would test the L-5 dermatome. Statistically, most neuropathic ulcers occur at the ends of the toes and plantar to the metatarsal heads.36-40
The proper method of administering the test is for the monofilament to touch each test site only once. The monofilament should touch the skin with enough force to just deform it before being removed from the site. It should be gently pressed against the skin until it mildly bends, not “poked” on the skin as would be done in a “sharp/dull” discrimination test.(Figure 3) The foot should be considered “at risk” if any portion of the foot is insensate to the 5.07 monofilament test.24,41
Before the practitioner administers the monofilament test, the patient must be educated about the test and acknowledge their role in responding to the test. I show the monofilament to the patient, and then touch their hand or arm with it so they will know what it feels like. Then I instruct the patient to say the word ”yes” if they feel the monofilament when it is touched to their skin. At this point, the patient is laid back in the treatment chair and asked to close their eyes.
There are three different variations or methods to performing this test. The first is the “Yes-No Method.” In this method, patients are instructed to say “yes” if they feel the monofilament when it is touched to their foot. A verbal “yes “or no response when the monofilament is touched to the foot is the only acceptable response to the test. A “grunt” or “I reckon” are not acceptable responses.
The second method is called the “Forced Choice Method.” In this variation, the patient is told that the examiner will say the words “one” and then “two.” The monofilament will be touched to the foot during either the “one” or “two” count. Patients are then asked to report if they felt the monofilament after the word “one” or the word “two”.
The third method, which has been described to me by numerous practitioners dating back to 1978, is called the “Location Method.” The monofilament is touched to the foot and patients must report which foot and the specific location that was touched: under the big toe, under the ball of the foot or under the small toe area. It is never appropriate to ask patients, “Did you feel it?” when the monofilament is touched to the foot. This can cause them to believe that the foot is being touched and that they should say “yes,” even if they do not feel the monofilament touch the skin.
The durability of the monofilament is another issue in performing a valid test. All monofilaments decrease in force after repetitive use. In a busy practice, if nine sites are tested per foot (hallux, each of five metatarsal heads, plantar base of the fifth metatarsal, plantar medial arch and heel) and the filament is used bi-laterally, there can be a total of 18 cycles per patient. If 10 diabetic patients are examined per day, three to five days per week, the filament could encounter 500 to 900 cycles weekly. In one study, the average decrease in deformation force due to the repetitive use of the filament was 1.2 g after 500 uses.42 Because a new 5.07 monofilament requires 10 g of force to deform it, this type of decrease in force could lead to false positives. It is therefore important to be aware of usage and discard the filament in a timely fashion.
Foot deformities of the bones, soft tissues, or toenails are not more prevalent but are more problematic in the diabetic patient, as they interact with shoe gear or their environment. This can lead to abnormal forces or silent, painless trauma to the foot. Once the skin is injured, a wound can develop and become infected. The combination of neuropathy, vascular insufficiency and immunopathy can delay wound healing and lead to amputation.
In the patient with diabetes, footwear is meant to cover, support, and protect the foot. It is critical to identify foot deformities so that patients can use appropriately sized footwear and accommodate the shape of their foot to protect it from a triggering event such as mechanical trauma.
Bone deformities in the foot can be the result of faulty biomechanical function, diabetic motor neuropathy or a combination of both.43 In motor neuropathy, the nerves that innervate the 13 lumbricales and interossei muscles in the foot malfunction. The result is muscle atrophy, which can be measured by MRI and causes joint contractures in the toes that lead to bone and soft tissue deformities.
Bone deformities cause new pressure points against the foot that can be triggers leading to an amputation. These include:
1. Hallux Abducto Valgus- A medial deviation of the first metatarsal and lateral deviation and/or rotation of the hallux. (Figure 4)
2. Hammer Toe- A joint contracture deformity of the proximal interphalangeal joint
3. Mallet Toe- A joint contracture deformity of the distal interphalangeal joint
4. Claw Toe- A joint deformity involving the metatarsophalangeal joint and both the proximal and distal interphalangeal joints (Figure 5)
5. Tailor’s Bunion- An angular joint deformity of the fifth toe at the metatarsophalangeal joint on the lateral aspect of the foot. (Figure 6)
Soft tissue deformities, primarily keratoses, result from the body’s natural protective mechanism to shield the underlying bony structure from excessive pressure, caused by shoes or the environment. Due to sensory neuropathy and the loss of protective sensation, the patient with diabetes often cannot feel the pressure against the foot from the thickened skin lesions. The result can be the formation of an abscess under the keratosis. If not detected in a timely fashion, these abscesses can lead to infection, ulceration and osteomyelitis.
Appropriate preventive care includes professional foot care for timely debridment of the keratosis, padding, accommodative insoles, or biomechanical orthotics with accommodations to offload the pressure sites. Shoe modifications, diabetic shoes or custom molded shoes may also be considered. Prophylactic surgical care to eliminate the bony pressure point is also an accepted method of care.
Too often, toenails are overlooked. The nails can become thick and deformed due to mold, yeast and fungal infections.(Figure 7) Shoe pressure against these deformed toenails can cause a subungual abscess. Additionally, a long, thick or deformed nail can lacerate an adjacent digit, which can trigger the process of infection that can lead to amputation.44
Topical antifungal medications are not FDA approved and are ineffective against this type of nail infection. Oral terbinafine or itraconazole are effective against this type of infection, but patient selection is critical for the safe
and effective use of these medications. Confirmation of mycotic nail infection before prescribing medication is essential to minimize costs and potential drug-related complications. Testing for nail mold, yeast or fungal infections should be done before prescribing an oral antifungal medication. Foot care specialists should consider nail debridement and ongoing foot care to decrease the risk of a triggering event, such as a digital laceration during self nail care, that could lead to amputation.
Performing a valid foot examination for amputation prevention involves the identification of pedal risk factors of the vascular and neurological systems and deformities of the bones, soft tissues and toenails. Identification of the patient’s pedal risk factors and establishing a preventive foot care plan to prevent ulcers, infections, and amputation in the patient with diabetes is critical to ulcer and amputation prevention, increasing the patient’s quality of life, and controlling health care costs.
Mark Hinkes, DPM, is chief of podiatry and director of podiatry education at the Veterans Affairs Medical Center in Nashville and the VAMC in Murfeesboro, TN. He is also chairman of the VA’s PACT (Preservation-Amputation Care and Treatment) program. His book, Keep the Legs You Stand On, is available at www.amputationprevention.com.
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