Author(s): Akinpelumi Beckley, MD, Ymi Ton, MD, MS, Christopher Kevin Wong, PT, PhD
Originally published: July 30, 2012 Last updated: January 9, 2025
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Disease/Disorder

Definition

Lower-limb amputation is the removal of a part, or multiple parts, of the lower limb. It is generally accepted that “major” amputations include those which are at or above the ankle.

Etiology

An estimated 56-93% of lower limb amputations are due to peripheral artery disease (PAD).1 PAD also known as dysvascular disease is caused by atherosclerosis of the peripheral arteries. Age, hypertension, hyperlipidemia and smoking are risk factors for this condition. Diabetes increases the risk of development of PAD and PAD increases risk of diabetes.2 People with both conditions are more likely to have refractory ulcers, claudication symptoms and require amputations.3 Trauma was previously responsible for up to 45% of amputations however the prevalence of people with amputations due to trauma is shrinking as the incidence of amputation surgeries due to trauma declines. Cancer accounts for less than two percent of total amputations.4

Epidemiology including risk factors and primary prevention

There were over 115,000 amputations in 2003, of which approximately 55,000 were classified as major amputations – defined as at or above the ankle.5 Despite the increase in the burden of diabetic disease, the overall rate of major amputations in the United States has decreased. While rates of major lower extremity amputation decreased by 40% between 1996 and 2011 among US Medicare recipients, from 2010 through 2015 there was a reversal with uptrend driven notably by younger and middle aged adults, and men. The amputation rate for US Medicare patients as of 2011 was 188 per 100,000.6 It is estimated that 3.6 million people with amputation will be living in the United States by 2050, of whom approximately 65% underwent lower limb amputation.4 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.1,7

Minority populations have been shown to have different incidences of lower limb amputation for reasons not currently understood.6 In the United States, 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.8 Men more frequently require amputation than women, especially for PAD. In comparison with countries studied in the Global Lower Extremity Amputation Study (GLEAS), the United States had higher amputation rates, even with similar population sizes and rates of diabetes. Amputation rates were lower for African Caribbean males and South Asians in the United Kingdom than Caucasians contradicting trends seen in the United States.1

Persons with diabetes and PAD have a much higher risk of amputation than the general population. Significant reduction in the incidence of lower extremity amputation has been achieved with the increased utilization of endovascular interventions6,10 and specialized diabetic foot care clinics.9 Diabetic self-management and foot screening programs are effective in reducing the risk of foot ulcers and subsequent amputations.4

Patho-anatomy/physiology

PAD acts to disrupt the lining of the arterial walls with resulting platelet aggregation and plaque formation. Diabetes causes the release of chemicals that increase inflammation which narrows the arteries and contributes to plaque formation. These factors contribute to decreased blood flow (ischemia) which prevent ulcers from healing properly or can cause pain from lack of oxygen (claudication) Patients with advanced PAD develop critical limb ischemia which is manifested by rest pain, ischemic skin lesions such as ulcers or gangrene.2,3 Poor blood sugar control, improper foot wear and associated neuropathy in patients with PAD are contributory factors in the development of diabetic foot ulcers. Ulceration has been demonstrated as the most likely precursor to amputation.11

Motor vehicle accidents followed by industrial (machinery, agricultural equipment, and construction sites) are the leading causes of traumatic amputations. Fireworks, firearms and electrocution are also a significant contributor to injury. In countries with recent history of warfare or civil unrest, explosive devices such as land mines or improvised explosive devices (IED) can result in amputation from blast injury or fragments severely damaging soft tissue.

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

Approximately one-quarter of patients with PAD 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.10 Critical limb ischemia is the final stage in PAD and can result in necrosis or gangrene of the limb with irreversible tissue loss.2 Diabetic foot ulcers occur in presence of neuropathy with the development of a callus from physical deformity and repetitive trauma. This causes subcutaneous hemorrhage then resultant ulcer formation.11 Diabetic amputees are more likely than non-diabetic amputees to experience progression to a higher level of amputation for all initial amputation levels.6

Specific secondary or associated conditions and complications

Complications and associated conditions after lower-limb amputation include infection, phantom limb sensation and pain, 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 for persons with transtibial and transfemoral amputation, respectively.

Essentials of Assessment

History

There is a strong role for a multidisciplinary approach to the preoperative evaluation of lower-limb amputation, in which an accurate history and physical examination ensure the most successful outcomes.12 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 support systems and home environment, and the status of the contralateral limb as well as the upper limbs. Identifying co-morbid illnesses, pain, and smoking status are also important factors in poorer outcomes.13 The goal is to develop an optimal surgical and rehabilitation plan based on each patient’s unique biopsychosocial profile.

Physical examination

Thorough skin inspection is essential in PAD and diabetic patients, both for prevention of initial amputation as well as prevention of re-amputation or amputation in the contralateral limb. Particular attention should be paid to the plantar aspect 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 limitation in foot/ankle range of motion, and/or ill-fitting footwear. Footwear should be examined not only for fit, but also for foreign bodies, as patients with PAD or diabetes 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 functional assessment and educating the patients on amputation-related issues should be implemented. The physician 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.14 Emphasis is placed on daily skin hygiene and regular skin inspection to maintain skin 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 can help identifying psychosocial and emotional stressors which may be 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 flexibility and joint mobility, strength and exercise programs, functional mobility and patient education regarding self-assessment of the residual limb, pain control, prosthetic fit and management, and community mobility.

Laboratory studies

Laboratory studies may be indicated if there is concern for cellulitis, deep tissue infection or osteomyelitis. An elevated white blood cell count, erythrocyte sedimentation rate (ESR) or C reactive protein (CRP) level can point towards an infection of an ulceration. Blood sugar also should be controlled with a hemoglobin A1C level below 7.5.11

Imaging

X-ray can help determine the presence of osteomyelitis and help rule out other bony pathology such as fracture or heterotopic ossification. 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 involvement. 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.

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.15 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. A vibration perception threshold is greater than 25 V is strongly correlated with increased risk of ulcer recurrence.11

Early predictions of outcomes

Factors that predict reduced post-amputation ambulation include higher modified frailty index and higher body mass. Additionally, people with higher chronic alcohol use, dependent pre-operative functional status, lack of family support, non-married and those with an above knee amputation were less likely to be ambulatory.16 The BLAR tool utilizes some of these factors in predicting the likelihood of ambulation post-amputation.17

In looking specifically at traumatic amputations, people with below knee amputations had higher physical component scores than those with through knee or above knee amputations. Although people with through knee amputations were more capable of walking 500 meters than those with above knee amputations, they were less likely to wear their prosthesis and had significantly more pain symptoms.18

Environmental

Amputations in the elderly have increased due to increasing longevity; the result of better medical technologies and lifestyles. Consistent factors that are predictive of risk for lower-extremity amputation include: age, sex, minority status, the presence of diabetes, educational status, PAD, neuropathy, and previous amputation.4

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 rehabilitation therapies, assisting in ADLs and mobility as necessary, and aiding with a 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 peer support groups as well as reintegration into spiritual communities. Visitation by a certified peer visitor is recommended early and throughout the post-amputation phase.13

Rehabilitation Management and Treatments

In the immediate post-amputation period, care should be taken to avoid placement of pillows under knee joint to reduce risk of hip or knee flexion contractures. A rigid or semi-rigid dressing is preferred to reduce swelling and protect the residual limb without increasing infection risk. Acute inpatient rehabilitation is recommended over skilled nursing facility for pre-prosthetic training. It has been shown that care in an acute inpatient rehabilitation leads to improved quality of life, ambulation, confidence with gait, prosthetic use and fewer pain complaints compared to that in a skilled nursing facility. Use of both open and closed chain exercises as well as progressive resistance can improve gait, mobility, strength, cardiovascular fitness, and ability to perform activities of daily living.13

Cutting Edge/Emerging and Unique Concepts and Practice

Phantom limb syndrome is the sensation of the presence of a limb that has been amputated and is reported by up to 80% of patients following procedure. Less frequently, phantom limb syndrome is painful in nature with an increased likelihood in lower limb amputees, residual limb pain or concurrent diabetes. Phantom limb pain has been challenging to assess; however, the limb laterality recognition score has been demonstrated to be reliable and inversely related with pain severity.19 Unfortunately, there is a lack of high-quality evidence for utilization of anti-convulsants such as gabapentin or pregabalin, NMDA receptor antagonists, or anti-depressants in management of pain symptoms. Mirror therapy or motor imagery are also modalities that are being investigated, but lack high quality, clinically controlled trials. Symptoms of phantom limb pain tend to improve over time and for patients who have identifiable triggers, avoiding exposure can reduce frequency of episodes. A newer surgical procedure that is being utilized in primary amputation, and secondarily, is Targeted Muscle Reinnervation (TMR). A process by which residual peripheral nerves are reattached to new target muscle of the residual limb. Applications such as neural control for advanced prostheses have been studied, but it may also be considered to reduce the post-operative development of neuroma and phantom limb pains. While further studies are required, TMR may reduce the likelihood for development of neuroma formation, restore normal sensory feedback and prevent phantom limb pain.20

Gaps in the Evidence-Based Knowledge


Currently, there is insufficient evidence on newer surgical techniques, such as the Burgess, Ertl, or Gritti-Stokes, are superior to traditional methods. Osseous integration and neural prostheses remain of limited application for most patients undergoing lower limb amputation procedures. There remains a need to establish pharmacological and therapeutic interventions for the treatment phantom limb pain. Medicare has established guidelines for intended use of prosthetics and components (K-levels). K-0 would not be able to utilize a prosthetic for transfers or ambulation. A K-1 would expect limited or unlimited ambulation within the household whereas K-2 would be capable of limited community ambulation allowing for navigating low level environmental barriers such as curbs, stairs or uneven surfaces. A K-3 level user would be able to ambulate at variable cadence with the ability to navigate most environmental barriers for vocational, therapeutic or exercise activity. The highest level, K-4 would have needs that exceed basic ambulation allowing for high impact, stress or energy levels such as athletes, active adults or children. One important step, however, is Medicare guidance allowing microprocessor knees for K-2 level prosthetic users which had previously been restricted to K-3 and K-4 level users. It will be important to observe if this change results in increased prosthetic utilization and function.

References

  1. Renzi R, Unwin N, Jubelirer R, et al. An international comparison of lower extremity amputation rates. Ann Vasc Surg. 2006;20(3):346–350.
  2. Hardman RL, Jazaeri O, Yi J, Smith M, Gupta R. Overview of classification systems in peripheral artery disease. Semin Intervent Radiol. 2014;31(4):378-388. doi:10.1055/s-0034-1393976
  3. Achim A, Stanek A, Homorodean C, et al. Approaches to Peripheral Artery Disease in Diabetes: Are There Any Differences?. Int J Environ Res Public Health. 2022;19(16):9801. Published 2022 Aug 9. doi:10.3390/ijerph19169801
  4. 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.
  5. Nowygrod R, Egorova N, Greco G, et al. Trends, complications, and mortality in peripheral vascular surgery. J Vasc Surg. 2006;43(2):205-216. doi:10.1016/j.jvs.2005.11.002
  6. Barnes JA, Eid MA, Creager MA, Goodney PP. Epidemiology and Risk of Amputation in Patients With Diabetes Mellitus and Peripheral Artery Disease. Arterioscler Thromb Vasc Biol. 2020;40(8):1808-1817. doi:10.1161/ATVBAHA.120.314595
  7. Newhall K, Spangler E, Dzebisashvili N, Goodman DC, Goodney P. Amputation rates for patients with diabetes and peripheral arterial disease: the effects of race and region. Ann Vasc Surg. 2016; 30:292–8.e1. doi: 10.1016/j.avsg.20
  8. Moxey PW, Gogalniceanu P, et al. Lower extremity amputation: a review of global variability incidence. Diabetic Medicine. 2011; 28: 1144-1153.
  9. Fosse S, Hartemann-Heurtier A, et al. Incidence and characteristics of lower-limb amputations in people with diabetes. Diabetic Medicine. 2009; 26: 391-396.
  10. Liu R, Petersen BJ, Rothenberg GM, Armstrong DG. Lower extremity reamputation in people with diabetes: a systematic review and meta-analysis. BMJ Open Diabetes Res Care. 2021;9(1):e002325. doi:10.1136/bmjdrc-2021-002325
  11. Armstrong DG, Boulton AJM, Bus SA. Diabetic Foot Ulcers and Their Recurrence. N Engl J Med. 2017;376(24):2367-2375. doi:10.1056/NEJMra1615439
  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.
  13. Webster JB, Crunkhorn A, Sall J, Highsmith MJ, Pruziner A, Randolph BJ. Clinical Practice Guidelines for the Rehabilitation of Lower Limb Amputation: An Update from the Department of Veterans Affairs and Department of Defense. Am J Phys Med Rehabil. 2019;98(9):820-829. doi:10.1097/PHM.0000000000001213
  14. Wong CK, Chihuri ST, Santo EG, White RA. Relevance of medical comorbidities for functional mobility in people with limb loss: retrospective explanatory models for a clinical walking measure and a patient-reported functional outcome. Physiotherapy. 2020;107:133-141. doi:10.1016/j.physio.2020.01.002
  15. American Diabetes Association. Standards of Medical Care in Diabetes—2008. Diabetes Care 2008 Jan; 31(Supplement 1): S12-S54.https://doi.org/10.2337/dc08-S012
  16. Chopra A, Azarbal AF, Jung E, et al. Ambulation and functional outcome after major lower extremity amputation. J Vasc Surg. 2018;67(5):1521-1529. doi:10.1016/j.jvs.2017.10.051
  17. Bowrey S, Naylor H, Russell P, Thompson J. Development of a scoring tool (BLARt score) to predict functional outcome in lower limb amputees. Disabil Rehabil. 2019;41(19):2324-2332. doi:10.1080/09638288.2018.1466201
  18. Penn-Barwell JG. Outcomes in lower limb amputation following trauma: a systematic review and meta-analysis. Injury. 2011;42(12):1474-1479. doi:10.1016/j.injury.2011.07.005
  19. Wong CK, Wong CK. Limb Laterality Recognition Score: A Reliable Clinical Measure Related to Phantom Limb Pain. Pain Med. 2018;19(4):753-756. doi:10.1093/pm/pnx179
  20. Culp CJ, Abdi S. Current Understanding of Phantom Pain and its Treatment. Pain Physician. 2022;25(7):E941-E957.

    Original Version of the Topic

    Alberto Esquenazi, MD, Michael Kwasniewski, MD. Amputation Epidemiology and Assessment. 7/30/2012.

    Previous Revision(s) of the Topic

    Alberto Esquenazi, MD, Stanley K. Yoo, MD. Amputation Epidemiology and Assessment. 5/3/2016.

    Alberto Esquenazi, MD, Michael Kwasniewski, MD. Lower Limb Amputations: Epidemiology and Assessment. 6/29/2021.

    Author Disclosures

    Akinpelumi Beckley, MD
    Nothing to Disclose

    Ymi Ton, MD, MS
    Nothing to Disclose

    Christopher Kevin Wong, PT, PhD
    Nothing to Disclose