Principles of Amputation

Original Editor - Lucy Coughlan as part of the World Physiotherapy Network for Amputee Rehabilitation Project

Top Contributors - Admin, Aicha Benyaich, Tarina van der Stockt, Stacy Schiurring, Rachael Lowe, Tony Lowe, Kim Jackson, Shaimaa Eldib, Sheik Abdul Khadir, Rucha Gadgil, Lauren Lopez, Simisola Ajeyalemi, Amrita Patro, Wanda van Niekerk and Jess Bell  

Introduction

Amputation is the surgical removal of a limb, or part of a limb. It may be required following trauma, prolonged constriction of the limb, or performed as a planned procedure to control pain or a disease process in the affected limb, such as malignancy, infection, or gangrene. Prolonged constriction refers to sustained circumferential compression that cuts off blood supply to the limb; this may be congenital, as in constriction band syndrome, or acquired, such as a tourniquet or hair tourniquet left in place too long. In some cases, amputation is carried out as a preventative measure to avoid such problems developing, and some individuals are born with limb absence due to congenital disorders.

Every care should be taken to assure that the amputation is done only when clinically indicated. Amputation should only be considered if the limb is non-viable (ie. gangrenous or grossly ischemic), dangerous (ie. malignancy or infection), or non-functional.

A well-planned and executed amputation can remove a painful, dysfunctional limb and allow rehabilitation with a prosthetic limb to a more functional, pain-improved state. Rather than representing a failure of treatment, amputation can offer genuine benefits over prolonged attempts at limb salvage: it removes the source of chronic pain, infection, or malignancy in a single, definitive procedure; avoids the physical and psychological burden of repeated salvage surgeries with uncertain outcomes; and allows rehabilitation to begin promptly, often producing a more functional and reliable result than a salvaged limb left with poor sensation, weak function, or ongoing pain. In this regard, amputation surgery may be considered reconstructive surgery, with outcomes comparable to joint replacement.

This Physiopedia page will overview the key principles guiding the decision to amputate, the goals and terminology of amputation surgery, and the surgical considerations, advantages, and disadvantages associated with each level of lower and upper limb amputation.

Assessment for Amputation

A decision to amputate a limb should be made through discussion with the interdisciplinary team, including the patient, wherever possible. In an emergency situation, the decision should be made based on medical need. A number of investigations may be used to assess limb viability and the underlying cause, examining the bones, soft tissues, and blood vessels:

Investigation	What it assesses
Pulse examination and Ankle-Brachial Index (ABI)	Bedside screening for reduced arterial blood flow First-line, non-invasive, and quick to perform Often the starting point before further imaging is considered
Toe-Brachial Index (TBI)	Alternative to ABI when arterial calcification is suspected Toe arteries are less prone to the medial calcification that can falsely elevate an ABI reading
X-ray	Bones: fractures or bone disease
Computerised Tomography (CT) scan	Detailed cross-sectional images of bone, soft tissue, and blood vessels
Magnetic Resonance Imaging (MRI)	Detailed soft tissue imaging Particularly useful for assessing tumour extent or the spread of infection
Duplex/colour Doppler ultrasound	Blood flow and vessel occlusion Non-invasive Often the first-choice vascular imaging investigation
Angiography (CT, MR, or catheter)	Direct visualisation of arteries, pinpointing the location and severity of a blockage CT/MR angiography are non-invasive and typically used first Catheter angiography is invasive but allows treatment (eg. angioplasty or stenting) within the same procedure
Venogram	Detailed imaging of the venous system
Transcutaneous oxygen pressure (TcPO2)	Measures skin oxygenation directly at a proposed amputation site Used specifically to help select the amputation level most likely to heal; values above roughly 30–40mmHg are generally associated with good healing potential, while values below roughly 20mmHg indicate a substantially higher risk of failed healing

The choice of investigation depends on the suspected underlying cause: vascular tests such as ABI, TBI, Duplex ultrasound, and angiography help establish whether blood supply to the limb remains intact, while X-ray, CT, and MRI are more broadly useful for assessing bone integrity, infection spread, or tumour extent.

Arterial Supply of the Limbs

Understanding the normal arterial supply of the limbs helps clinicians interpret vascular investigations, localise the level of an occlusion or injury, and anticipate how proximally an area of compromised blood flow may extend; all of which inform both diagnosis and the eventual choice of amputation level.

Arteries of the lower limb

Lower limb: the leg is supplied by a staged arterial chain running from the groin to the foot:

• External iliac artery, which becomes the femoral artery as it passes beneath the inguinal ligament
• Femoral artery, which runs down the thigh and becomes the popliteal artery at the adductor hiatus
• Popliteal artery, which divides behind the knee into the anterior tibial artery and the tibioperoneal trunk
• Anterior tibial artery, which runs down the front of the leg and continues into the foot as the dorsalis pedis artery
• Tibioperoneal trunk, which divides into the posterior tibial artery and the fibular (peroneal) artery
• Posterior tibial artery, which passes behind the medial malleolus and divides into the medial and lateral plantar arteries supplying the sole of the foot
• Fibular (peroneal) artery, which supplies the lateral compartment of the leg and contributes to the collateral network around the ankle

Arteries of the upper limb

Upper limb: the arm and hand are supplied by a longer arterial chain running from the shoulder to the digits:

• Subclavian artery, which becomes the axillary artery at the shoulder
• Axillary artery, which becomes the brachial artery in the upper arm
• Brachial artery, which divides at the elbow into the radial and ulnar arteries of the forearm
• Radial and ulnar arteries, which join in the hand to form the superficial and deep palmar arches
• Palmar arches, which give rise to the digital arteries supplying the fingers

In vascular disease, these arteries can become blocked or narrowed over time, reducing circulation to the affected limb. This can cause pain, ulceration, and blackened areas, and if left untreated, can progress to gangrene or infection, at which point amputation may be needed to prevent a life-threatening outcome. Atherosclerotic disease affecting the upper limb is considerably less common than in the lower limb, since the richer collateral circulation around the shoulder girdle provides better compensation for a narrowing artery; when it does progress to amputation, it more often results from acute embolism, trauma, or thoracic outlet compression than from the chronic atherosclerotic process that dominates lower limb disease.

In trauma one or more of these blood vessels may be ruptured beyond repair, eg. in a road traffic collision, gunshot wound, or blast injury. In this situation, amputation is performed because the limb has no blood supply beyond the level of injury and is therefore non-viable.

A number of injury severity scores may be used alongside clinical investigations to establish the likelihood of successful limb salvage, including:

• Mangled Extremity Severity Score (MESS)
• Nerve Injury, Ischemia, Soft-Tissue Injury, Skeletal Injury, Shock, and Age of Patient Score (NISSA) developed by McNamara et al. as a modification of the MESS, adding assessment of nerve injury
• Limb Salvage Index (LSI)

Amputations are broadly classified as minor (eg. toe and partial foot amputations) or major (eg. amputation of most of the limb). Once a decision has been made to amputate, the level of amputation must be determined; this has significant consequences, so several factors are considered when planning surgery. The amputation should be performed at a level where all dead or diseased tissue can be fully resected, since incomplete eradication of infection or disease may otherwise require further surgery. The level must also be chosen with prosthetic suitability in mind if the patient is likely to be a candidate for prosthetic rehabilitation, taking their pre-morbid mobility and functional level into account. Finally, the resulting residual limb length and shape affect cosmesis, which should also be considered during surgical planning.

Goals of Amputation Surgery

Amputation surgery is reconstructive in intent, not simply ablative. The overarching goals are to manage pain effectively, both immediately post-operatively and over the longer term, and to preserve optimal residual limb length for the level being amputated, balancing lever-arm function against adequate soft-tissue coverage.

These goals are put into practice through the surgeon's choice of muscle stabilisation technique. Myodesis secures the muscle directly to bone by suturing the distal tendon through pre-drilled holes, and can be performed at below-knee, above-knee, and other amputation levels; by limiting excessive muscle shift during contraction, it helps prevent deformity of the residual limb and preserves muscle control within the prosthesis. Myoplasty takes a different approach, attaching sectioned muscles to their opposing (antagonist) muscles rather than to bone.

Wound healing should be achieved in a way that supports prosthetic fitting, without compromising closure by prioritising length over healthy tissue margins. Painful neuroma formation should be minimised by dissecting nerves under gentle tension so the cut end retracts proximally into well-vascularised tissue, away from the distal residual limb and the future prosthetic socket interface. Mobility in adjacent joints should be preserved and contractures avoided, since these increase energy expenditure during prosthetic gait and can compromise fitting. Finally, the multidisciplinary team should be involved early, ideally from the pre-operative stage where the clinical picture allows, so that rehabilitation and prosthetic goals inform surgical decision-making rather than being addressed only afterwards.

More recent surgical advances aimed at reducing neuroma-related pain and phantom limb pain include:

• Targeted muscle reinnervation (TMR): a nerve transfer of a proximal (mixed or sensory) nerve into a distal motor nerve
• Regenerative peripheral nerve interfaces (RPNI): an autologous free muscle graft wrapped around the transected nerve end.

Evidence for both techniques is growing but should still be regarded as an evolving area of practice rather than a universally established standard of care.

The following two short videos provide an overview of targeted muscle reinnervation and regenerative peripheral nerve interface procedures and potential benefits/outcomes:

Lower Limb Amputations

Amputation level is chosen based on the factors described in Assessment for Amputation above, ranging from the toes to the hip.

Level	Description	Advantages	Disadvantages
Toe	Through the phalanges, or disarticulation at the metatarsophalangeal joint (avoided where possible, as it exposes avascular cartilage) || Most common lower limb amputation || Affects balance and late-stance push-off, particularly for the great toe May contribute to hallux valgus Alters the foot's transverse arch
Ray	The toe plus its corresponding metatarsal	—	Disrupts the transverse arch Effect on gait depends on which ray is removed (1st and 5th ray loss most disruptive) Wound may be left open if infected
Transmetatarsal	Through the metatarsals	Excellent function achievable with good wound healing	Increased plantar pressure (risk of calluses/ulcers) Shortened foot lever arm Risk of plantar flexion contracture
Midfoot/hindfoot	Tarsometatarsal (Lisfranc) - amputation of the forefoot at the tarsometatarsal line. Mid-tarsal (Chopart) - amputation between the talus and the calcaneus proximally and the cuboid and the navicular distally. Ankle disarticulation (Symes) – amputation through the ankle joint Lisfranc and Chopart are midfoot disarticulations; Syme's is hindfoot level	Range of prosthetic options eg. insoles, toe fillers, AFOs (except after Syme's) Mainly used in children to preserve growth plates	May require further surgery Risk of skin breakdown and joint pain Cosmesis not always well accepted

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  Great toe amputation
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  5th ray amputation
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  Transmetatarsal amputation
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  Midfoot/hindfoot amputation levels

Level	Description	Advantages	Disadvantages
Transtibial (BKA)	Through the tibia and fibula Ideal length ~12–17cm from the joint line	Preserves the knee joint, lower energy expenditure and better proprioception than transfemoral Candidacy for a patella tendon-bearing prosthesis Better ambulation outcomes in older adults than transfemoral	Risk of knee flexion contracture May require additional procedure (Ertl bone-bridge surgery) for distal fibula pain

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  Cylindrical stump (fibula 5-10 mm shorter)
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  Long posterior muscular flap covering the distal end, attached ventrally to a shorter anterior flap (ventral suture)
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Level	Description	Advantages	Disadvantages
Knee disarticulation	Through the knee joint	Long lever arm Preserves muscle length/strength and growth plates Candidacy for an end-bearing prosthesis	Bulkier, less cosmetic prosthesis (knee mechanism sits below the natural joint line) More demanding surgery

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Level	Description	Advantages	Disadvantages
Transfemoral (AKA)	Through the femur; current guidance favours preserving maximum length where soft tissue allows	Longer residual limb: better lever arm, muscular balance, and energy efficiency; ischial tuberosity-bearing prosthesis candidacy	Shorter residual limb: weaker adductors, flexion/abduction positioning, and substantially higher energy cost

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• 
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  Very short trans-femoral stumps often end up in abduction because there is an imbalance between the adductor and abductor muscles.

Level	Description	Advantages	Disadvantages
Hip disarticulation	Through the hip joint	Candidacy for an ischial tuberosity-bearing prosthesis	High risk of wound complications and mortality; usually wheelchair-dependent
Hemipelvectomy	Whole limb plus ipsilateral hemipelvis	Rare candidacy for a trunk/contralateral IT-bearing prosthesis	Rare, complex procedure; usually wheelchair-dependent

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Surgical and residual lower limb length notes:

• Across all levels, nerves are dissected under gentle tension so the cut end retracts into well-vascularised tissue, reducing the risk of neuroma-related pain.
• Transtibial: below the ~12–17cm ideal range, function becomes progressively more compromised — under roughly 9cm may require full fibula removal with additional muscle bulk, and under roughly 5cm a more proximal level should usually be considered instead. An ultra-short 5–6cm stump is occasionally chosen deliberately to preserve the knee joint.
• Transfemoral: there is no single agreed optimum length; the literature ranges from roughly 9–17cm above the knee joint line, or is expressed as around two-thirds of the contralateral femur length. Myodesis anchors the adductors (and sometimes hamstrings) to bone; myoplasty sutures the hamstrings and quadriceps together over the residual femur; a Gottschalk myodesis additionally fixes the adductor magnus trans-osseously to pad the distal femoral end.

Optional additional reading about lower limb amputations:

• Partial-Foot Amputations: Surgical Procedures

• Transtibial Amputation: Surgical Procedures and Immediate Postsurgical Management

• Knee Disarticulation: Surgical Procedures

• Transfemoral Amputation: Surgical Procedures
• Hip Disarticulation and Transpelvic Amputation: Surgical Procedures
• Lower Limb Amputation Postoperative Care
• Rotationplasty

Energy Expenditure by Amputation Level

Energy expenditure during prosthetic gait increases with amputation level, and is generally higher in dysvascular-cause amputation than traumatic-cause amputation, since traumatic amputees are typically younger with higher baseline fitness and can compensate more effectively.

Amputation level	Approximate increase in energy expenditure vs able-bodied gait
Transtibial	~10–40%
Bilateral transtibial	~41%
Transfemoral	~60–70% (individual studies report a wider range, up to ~100%)
Transtibial (one side) + Transfemoral (other side)	~118%
Bilateral transfemoral	>200%

Upper Limb Amputations

Upper limb amputations are seen considerably less often than lower limb amputations, and trauma is the leading cause of upper limb amputation in adults, in contrast to lower limb amputation, which is predominantly dysvascular in origin.

Level	Description
Fingers	Partial or complete digit amputation
Partial hand	Through the metacarpals or carpus
Wrist disarticulation	Through the radiocarpal joint
Transradial	Through the forearm (radius and ulna)
Elbow disarticulation	Through the elbow joint
Transhumeral	Through the humerus
Shoulder disarticulation	Through the shoulder joint
Scapulothoracic dissociation (forequarter)	Removal of the arm, scapula, and clavicle

Optional additional reading about upper limb amputations:

• Partial hand
• Wrist disarticulation
• Transradial
• Elbow disarticulation
• Transhumeral
• Shoulder disarticulation
• Scapulo-thoracic dissociation (forequarter)

A range of prosthetic options is available for the upper limb, from body-powered hooks and purely cosmetic passive devices through to myoelectric and fully mechanical functional limbs. As with the lower limb, the amputation level strongly influences which prosthetic options are viable and how much residual native joint function remains for the person to control the device.

Prosthesis rejection rates rise fairly consistently with more proximal amputation level across the literature, though the exact figures vary considerably between studies: transradial users report the lowest rejection rates, with transhumeral and shoulder disarticulation users reporting substantially higher rates, most often attributed to limited device functionality relative to the effort of control. This is one of several reasons prosthetic and functional goals are best considered early and collaboratively with the patient.

Resources

Optional Additional Videos

Warning: video links to real surgical procedures

• Transfemoral
• Transtibial
• Transmetatarsal
• Knee Disarticulation