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Epidemiology and Assessment

  1. Disease/Disorder:
    Definition

    Lower-limb amputation is the removal of a part or multiple parts of the lower limb. Though there is some discrepancy in literature regarding exact distal boundaries, it is generally accepted that "major" amputations include those which are at or proximal to the ankle.

    Etiology
    Studies show that 93.4% of all lower-extremity amputations are due to dysvascular disease, with incidence increasing 27% from 1988 to 1996.1,2 Trauma, responsible for only 5.8% of lower-limb amputations, is the most common cause in the second and third decade of life. Cancer accounts for 0.8% of the total amputations, and is the most common cause between ages 10 and 20 years.1
    Epidemiology including risk factors and primary prevention

    The exact number of people who have had amputations worldwide is difficult to ascertain, as many countries do not keep records of the number of people with limb amputation. Each year over 150,000 individuals are admitted to hospitals to undergo amputations secondary to peripheral vascular disease or diabetes.4 As of 2005, an estimated 1.6 million people with amputation live in the United States, of whom approximately 65% underwent lower limb amputation.10 Of the approximately 1 million unilateral lower-extremity amputations due to dysvascular conditions, the most common were toe (33.2%), transtibial (28.2%), transfemoral (26.1%), and foot amputations (10.6%). Ankle disarticulation (Syme), through-knee, hip disarticulation, and hemipelvectomy amputations combined added an additional 1.5% of all amputations.1,2 Minority populations have been shown to have different incidences of lower limb amputation for reasons not currently understood.6 Asians were found to have a lower relative risk of lower limb amputation, while African Americans have a higher risk. This seems to be independent of other risk factors associated with minority status, such as a higher prevalence of diabetes and hypertension.9 Men more frequently require amputation than women, especially for vascular disease.

    Persons with diabetes are anywhere from 8-24 times more likely to undergo a lower limb amputation than non-diabetics.8 Patients who have diabetes tend to have more minor amputations (e.g., toe, ray, partial foot) than individuals who have peripheral vascular disease, who have more major limb amputations (ankle or proximal).1,7 Nonetheless, the frequency of subsequent amptuation is also higher in diabetics.8. Significant reduction in the incidence of lower extremity amputation has been achieved with the introduction of specialist diabetic foot care clinics,9 and this is reflected by projected limb loss estimates, which suggest a substantial decrease in the prevalence of individuals living with limb loss, with just a 10% reduction in incidence rates secondary to dysvascular disease.10

    Patho-anatomy/physiology

    The causes of amputation vary from country to country. In the developing world, trauma is the leading cause of amputation caused by inadequately treated fractures, motor vehicle accidents (motorcycle and train), and other motorized machinery. In countries with recent history of warfare or civil unrest, trauma can account for up to 80% of all amputations. In developed countries like the United States, Denmark and Japan, disease accounts for 68% of all amputations performed each year.5 Diabetes, peripheral vascular disease and infection are the predominant causes of non-healing ulcers which are, in turn, the principal cause of lower extremity amputation in the United States.9

    Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

    Approximately one-quarter of dysvascular patients will require subsequent amputation procedures within one year of initial amputation, with progression to higher level of limb loss or contralateral amputation more likely among patients with an initial foot or ankle amputation. Diabetic amputees are more likely than non-diabetic amputees to experience progression to a higher level of amputation for all initial amputation levels, and although it has been found that 12 month mortality rates are lower for diabetics, they are more likely to die at a younger age than non-diabetic dysvascular patients.4

    Specific secondary or associated conditions and complications

    Complications and associated conditions after lower-limb amputation include infection, phantom limb pain and sensation, residual limb pain, painful neuroma, and heterotopic ossification. Joint contracture is a common, often preventable, sequela of amputation, with knee and hip flexion contractures being most common after transtibial and transfemoral amputation, respectively.

  2. Essentials of Assessment
    History

    There is a strong role for a multidisciplinary approach to the preoperative evaluation for lower-limb amputation, in which an accurate history and physical examination ensure the most successful outcomes.12 Although emergent procedures such as amputation due to trauma or life-threatening infection may preclude preoperative evaluation, in many cases amputations can be delayed for this to be performed, in order to develop optimal surgical and rehabilitation plans based on each patient's unique biopsychosocial profile. In the history, particular attention should be paid to premorbid functional status, cognitive and psychological history, vision, obesity, cardiopulmonary and renal status, education level, the availability of social suport systems and home environment, and the status of the contralateral limb as well as the upper limbs.

    Physical examination

    Thorough skin inspection is essential in dysvascular patients, both for prevention of initial amputation as well as prevention of reamputation or amputation in the contralateral limb. Particular attention should be paid to bottom of the foot, as well as between the toes, as these are areas where skin integrity can be compromised either by foreign bodies, maceration or fissures in the epidermis from excessively dry skin. Any area where the skin is compromised is a potential area for infection. Existing skin wounds should be monitored closely for any signs of infection. Such findings should prompt further investigation including laboratory workup and/or imaging modalities. Callusing or blistering can be indicative of ill-fitting footwear, and footwear should be examined not only for fit, but also for foreign bodies, as dysvascular patients often have significantly impaired sensation in the distal lower limbs. Finally, all inspection and assessment techniques should be taught to and regularly performed by patients. A long-handled mirror is a useful aide for self-inspection of the lower limbs, as visualization is often limited by a patient’s flexibility and/or body habitus.

    Functional assessment

    Ideally, a team approach to clinical functional assessment and educating the patients on amputation-related issues should be implemented. The physican assesses medical stability, and addresses possible medical barriers to functional progress, while nursing and occupational therapy are instrumental in the assessment and instruction of self-care and medication management. Emphasis is placed on daily skin hygiene and regular skin inspection to maintain integrity. Proper nail care is also essential, and for many, regular podiatric assessment and nail/foot care may be warranted. Smoking cessation should be strongly encouraged in this patient population, and such services and education are often provided with the aid of a social worker and/or recreational therapist. A psychologist is useful in the identification of psychosocial and emotional stressors which may serve as barriers to functional progress or social reintegration, and counseling may be offered either in a group setting or on a one-to-one basis. Finally, both physical and occupational therapists assess issues related to functional mobilty, and provide patient education on self-assessment regarding residual limb care, prosthetic fit, pain management and mobility. It is necessary for the physiatrist, physical therapist and prosthetist to all be actively involved in assessment of prosthetic gait, and is particularly helpful when all are availalble to assess ambulation as a group, for example, during scheduled gait rounds.

    Laboratory studies

    Labarotory studies may be indicated if there is concern for osteomyelitis. Complete blood count (CBC) with differential can be useful in assessing for sepsis, as well as inflammatory markers such as erythrocyte sedimentation rate and C reactive protein.

    Imaging

    X-ray can help determine the presence of osteomyelitis and help rule out other bony pathology such as fracture or heterotopic ossificiation. Findings suggestive of osteomyelitis include cortical erosion, periosteal reaction, mixed lucency, sclerosis and soft tissue swelling, especially if there is accompanying cellulitis or abscess. If findings on plain film studies show concern for osteomyelitis, further imaging with magnetic resonance imaging (MRI) or bone scan is warranted. MRI is very sensitive for the detection of acute osteomyelitis, and can delineate the margins of cortical invovement. Specificity for osteomyelitis, however, is limited, as multiple pathologies can cause bony edema. Triple phase bone scan, which detects osteoblastic activity, may also be used and both sensitivity and specificity are high when corresponding plain film radiographs are normal. If non-infectious bony disorders are noted (e.g., acute fracture), reliability of this modality decreases.

    Supplemental assessment tools

    Use of 10-g Semmes-Weinstein monofilaments to evaluate foot sensation is an effective mode of examination and determination of potential for foot injury and amputation. The nylon monofilament is applied to various areas on the foot (e.g., the dorsum of the foot, metatarsal heads, great toe and heel) and is designed to bend at 10 grams of pressure. In this way, when applied to the skin surface, it provides a standardized measure of a patient's ability to sense a point of pressure.

    Early predictions of outcomes

    In a series of orthopedic studies labeled the Lower Extremity Assessment Project (LEAP),11 numerous factors were evaluated as potential predictors of outcome in attempts to create clinical guidelines regarding limb salvage versus amputation for patients with limb-threatening lower extremity trauma. From these studies, it was concluded there is no good measure to predict the potential success of limb salvage versus amputation. It was determined that the lower extremity injury severity indices studied were not helpful in determining which limbs were likely to be successfully salvaged. However, general predictors for successful outcome were identified. Negative predictors of self-reported health status as measured by the Sickness Impact Profile (SIP) included low self-efficacy, rehospitalization for major compication, lower educational level, non-white race, poverty, lack of private health insurance, poor social network, and the involvement of the patient in litigation. There was no difference in SIP scores between amputation and limb salvage groups at 2 years. Regarding employement, it was found that an assessment of pain and physical function as early as 3 months after surgery was a significant predictor of return to work at 7 years.

    Environmental

    Amputations in the elderly have increased due to increasing longevity, which is due to better medical technologies and life styles. By 2050, it is projected that the number of people living with limb loss will more than double as compared to 2005 estimates, to 3.6 million.10 Consistent factors that are predictive of risk for lower-extremity amputation include age, sex, and minority status, as well as the presence of diabetes, educational status, peripheral vascular disease, neuropathy, and previous amputation. The prevalence of lower-limb amputation increases with age, with >50% of diabetic amputees greater than 70 years of age.8 Individuals who have diabetes experience lower-limb amputation at a slightly younger age than those who have vascular disease alone.

    Social role and social support system

    There is a clear relationship between functional outcomes after lower-limb amputation and the availability of social support systems. Family and friends can be instrumental in assisting with transportation to and from therapies, assisting in ADLs and mobility as necessary, and aiding in the home exercise program. A strong social network is also invaluable for moral and spiritual support as well as patient education. Benefits gained from amputee education groups and chaplaincy/spiritual services offered on an inpatient basis, can be continued as an outpatient through continued participation in support groups as well as reintegration into spiritual communities.

  3. Rehabilitation Management and Treatments
  4. Cutting edge/emerging and unique concepts and practice
    Cutting edge concepts and practice

    Not available at this time.

  5. Gaps in the evidence-based knowledge
    Gaps in the evidence-based knowledge

    Not available at this time.

    References
    1. Dillingham TR, Pezzin LE, MacKenzie EJ. Limb amputation and limb deficiency: epidemiology and recent trends in the United States. Southern Medical Journal. 2002;95(8):875-879.
    2. Renzi R, Unwin N, Jubelirer R, et al. An international comparison of lower extremity amputation rates. Ann Vasc Surg. 2006;20(3):346–350.
    3. Baumgartner RF. The surgery of arm and forearm amputations. Orthop Clin North Am. 1981;12(4):805–817.
    4. Dillingham TR, Pezzin LE, Shore AD. Reamptuation, mortality, and health care costs among persons with dysvascular lower-limb amptuations. Arch Phys Med Rehabil. 2005; 86: 480-486.
    5. National Center for Chronic Disease Prevention and Health Promotion. Statistics: diabetes surveillance; non-traumatic lower extremity amputation. Washington, DC. Cendter for Disease Control, 1996.
    6. Young BA, Maynard C, Reiber G, et al. Effects of ethnicity and nephropathy on lower extremity amputation risk among diabetic veterans. Diabetes Care. 2003;26(2):495–501.
    7. Centers for Disease Control and Prevention. Diabetes-related amputations of lower extremities in the Medicare population. Morb Mortal Wkly Rep. 2001;50(43):954–958.
    8. Fosse S, Hartemann-Heurtier A, et al. Incidence and characteristics of lower-limb amputations in people with diabetes. Diabetic Medicine. 2009; 26: 391-396.
    9. Moxey PW, Gogalniceanu P, et al. Lower extremity amputation: a review of global variability incidence. Diabetic Medicine. 2011; 28: 1144-1153.
    10. Ziegler-Graham K, MacKenzie E, et al. Estimating the prevalence of limb loss in the United States: 2005 to 2050. Arch Phys Med Rehabil. 2008; 89: 422-429.
    11. Higgins TF, Klatt JB, Beals TC. Lower Extremity Assessment Project (LEAP): the best available evidence on limb-threatening lower extremity trauma. Orthop Clin North Am. 2010 Apr; 41(2):233-239.
    12. Hakimi KN. Pre-operative rehabilitation evaluation of the dysvascular patient prior to amputation. Phys Med Rehabil Clin N Am. 2009 Nov; 20(4):677-88.
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