Lower Limb Amputation Levels

Foot Level Amputations (Toe, Ray, TMA)

Toe Amputation Indications:

• Localized gangrene of single toe
• Osteomyelitis limited to phalanges
• Frostbite with demarcated necrosis
• Trauma with non-viable toe

Ray Amputation Indications:

• Gangrene extending to metatarsal head
• Osteomyelitis involving MTPJ
• Deep space infection requiring drainage
• Central ray for web space infection

Transmetatarsal Amputation (TMA) Indications:

• Multiple toe gangrene
• Forefoot osteomyelitis
• Failed toe/ray amputations
• Adequate midfoot perfusion

Key Considerations:

• High revision rate in vascular disease (30-50%)
• Watch for transfer ulcers on remaining toes
• Achilles lengthening may be needed with TMA to prevent equinovarus
• Requires adequate midfoot blood supply

Midfoot Amputations (Lisfranc, Chopart)

Lisfranc (Tarsometatarsal) Amputation:

• Disarticulation through tarsometatarsal joints
• Rarely performed - unstable foot, equinovarus common
• May be considered for trauma with viable hindfoot
• Requires tendo-Achilles lengthening

Chopart (Midtarsal) Amputation:

• Disarticulation through talonavicular and calcaneocuboid joints
• Historical interest - rarely performed today
• Severe equinus deformity inevitable
• Poor prosthetic options

Syme Amputation (Ankle Disarticulation)

Indications:

• Trauma with non-viable foot, intact heel pad
• Congenital deformities (fibular hemimelia)
• Tumour of foot with clear margins
• Failed forefoot surgery with viable heel

Requirements:

• Viable heel pad - essential for weight bearing
• Adequate posterior tibial artery supply
• Intact heel pad sensation (preferable)
• Experienced surgeon

Advantages:

• End-bearing stump
• Long lever arm for excellent prosthetic control
• Energy expenditure lower than transtibial
• Can bear weight without prosthesis (limited)

Disadvantages:

• Bulky distal stump - cosmetic concerns
• Requires specialized prosthesis
• Technically demanding
• Heel pad migration risk

Transtibial Amputation (Below-Knee)

Indications:

• Most common major amputation
• Vascular disease with adequate healing potential
• Trauma with intact knee
• Tumour not involving knee

Level Selection:

• Minimum: 12-15cm from tibial tuberosity
• Optimal: Junction of proximal and middle third
• Maximum: Fibula must allow flap closure

Key Points:

• PRESERVE THE KNEE - reduces energy by 40-60%
• Short BKA still better than AKA
• Long posterior flap (Burgess) is gold standard
• PTB (patellar tendon bearing) prosthetic socket

Knee Disarticulation and Transfemoral

Knee Disarticulation Indications:

• Transtibial not possible (short stump, healing concerns)
• Trauma with knee involvement
• Non-ambulatory patients (easier nursing care)
• Paediatric patients (preserves growth plates)

Transfemoral (AKA) Indications:

• Failed or contraindicated transtibial
• Vascular disease with poor healing distally
• Knee joint pathology (infection, tumour)
• Trauma with extensive proximal involvement

Transfemoral Key Points:

• Minimum 10-12cm from greater trochanter
• Equal anterior-posterior flaps
• Adductor myodesis to lateral femur - prevents abduction contracture
• Preserve adductor magnus insertion if possible

Hip Disarticulation and Hemipelvectomy

Hip Disarticulation Indications:

• Proximal femoral tumour
• Extensive proximal trauma
• Uncontrolled infection of thigh
• Failed transfemoral amputation (rare)

Hemipelvectomy Indications:

• Pelvic tumour with no other option
• Extensive infection involving pelvis
• Rarely performed - high morbidity

Key Considerations:

• Massive operation with high mortality risk
• Very high energy expenditure (greater than 200% increase)
• Most patients wheelchair-bound
• Canadian hip prosthesis available but limited use
• Require significant rehabilitation and support

Universal Principles for All Levels

Preoperative:

1. Optimize medical comorbidities (diabetes, cardiac, renal)
2. Smoking cessation (counsel and pharmacotherapy; smoking significantly impairs healing)
3. Nutritional optimization (albumin greater than 30 g/L)
4. Early prosthetist involvement
5. Psychological preparation and support

Intraoperative:

1. Appropriate level based on healing potential
2. Adequate bone length for lever arm
3. Sufficient soft tissue for tension-free closure
4. Myodesis (muscle to bone) for optimal function
5. Proper nerve handling - traction neurectomy

Postoperative:

1. Rigid dressing or IPOP (immediate post-op prosthesis)
2. Edema control - compression
3. Phantom pain management
4. Early rehabilitation and prosthetic fitting
5. Psychological support

Flap Design by Level

Toe/Ray Amputation:

• Fish-mouth or racquet incision
• Equal dorsal and plantar flaps
• Plantar flap may be longer for padding

Transmetatarsal:

• Long plantar flap preferred
• Plantar skin more durable for weight bearing
• Short dorsal flap

Syme Amputation:

• Posterior heel pad flap
• Sagittal incision extended to malleoli
• Preserve posterior tibial artery to heel pad

Transtibial (BKA):

• Long posterior flap (Burgess) - gold standard
• Posterior flap = 1.5 times AP diameter
• Short anterior flap at bone level
• Gastrocnemius provides durable coverage

Transfemoral (AKA):

• Equal anterior and posterior fish-mouth flaps
• Each flap = one-third circumference
• Apex at level of bone division

Bone Handling by Level

General Principles:

• Adequate length for lever arm and prosthetic control
• Smooth edges - rasp all bone ends
• Avoid periosteal stripping (prevents ring sequestra)
• Cover with muscle padding

Transtibial Specifics:

• Minimum 12-15cm from tibial tuberosity
• Anterior tibial bevel - 45 degrees to prevent skin pressure
• Fibula 1-2cm shorter than tibia
• Smooth edges with rasp

Transfemoral Specifics:

• Minimum 10-12cm from greater trochanter
• Junction of middle and distal third optimal
• Preserve adductors if possible for muscle balance
• Round edges with rasp

Special Techniques:

• Ertl procedure: Tibio-fibular synostosis for end-bearing
• Used in young trauma patients
• Creates bone bridge between tibia and fibula
• Allows direct end-bearing potential

Nerve Handling - Traction Neurectomy

Technique:

1. Identify nerve in proximal wound
2. Ligate accompanying vessels (artery runs with nerve)
3. Apply gentle longitudinal traction (2-3cm)
4. Use fresh sharp blade
5. Transect cleanly in single motion
6. Allow nerve to retract into proximal soft tissue
7. Position away from scar and prosthetic pressure areas

Major Nerves by Level:

Vessel Management:

• Identify and ligate major vessels
• Suture ligation for large vessels (SFA, popliteal)
• Diathermy for small vessels
• Meticulous hemostasis - hematoma increases infection risk

Toe Amputation Technique

Indications: Localized gangrene, osteomyelitis of phalanx, frostbite

Technique:

1. Racquet incision around base of toe
2. Disarticulate at MTPJ or PIPJ
3. Identify and ligate digital vessels
4. Transect digital nerves under traction
5. Close with interrupted sutures
6. Leave open if infected (delayed primary closure)

Ray Amputation Technique

Indications: Gangrene to metatarsal head, MTPJ osteomyelitis

Technique:

1. Racquet incision extending onto dorsum of foot
2. Incise along metatarsal shaft
3. Disarticulate at tarsometatarsal joint (or cut metatarsal)
4. Remove metatarsal and toe en bloc
5. Preserve intermetatarsal ligaments if possible
6. Close with slight narrowing of foot
7. Consider first or fifth ray specifically

Transmetatarsal Amputation (TMA)

Indications: Forefoot gangrene, failed toe/ray amputation, osteomyelitis

Preoperative:

• Confirm midfoot perfusion adequate
• Mark bone division level (mid-metatarsal shaft)
• Long plantar flap design

Technique:

Syme Amputation (Ankle Disarticulation)

Indications: Trauma with viable heel pad, congenital deformity, failed forefoot surgery

Requirements:

• Viable heel pad with intact sensation (preferable)
• Adequate posterior tibial artery
• Experienced surgeon

Technique:

Postoperative:

• Rigid dressing to prevent heel pad migration
• Non-weight bearing 6-8 weeks
• Gradual prosthetic fitting

Transtibial (Below-Knee) Amputation

The most important level to master for exams.

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Indications: Vascular disease, trauma, tumor with adequate proximal viability

Level Selection:

• Minimum: 12-15cm from tibial tuberosity
• Optimal: Junction of proximal and middle third
• Posterior flap = 1.5 times AP diameter of leg

Knee Disarticulation (Through-Knee Amputation)

Indications:

• Transtibial not possible
• Non-ambulatory patients (nursing care easier)
• Pediatric patients (preserves growth plates)
• Trauma with knee involvement

Advantages:

• End-bearing potential
• Long lever arm
• No bone cutting required
• Femoral condyles provide good prosthetic fit

Disadvantages:

• Bulky distal stump
• Cosmetically challenging prosthetic knee
• Limited prosthetic options

Technique:

Transfemoral (Above-Knee) Amputation

Indications: Failed/contraindicated transtibial, proximal vascular disease, tumor

Level Selection:

• Minimum: 10-12cm from greater trochanter
• Optimal: Junction of middle and distal third of femur
• Preserve adductor magnus insertion if possible

Hip Disarticulation

Indications:

• Proximal femoral tumor
• Extensive trauma
• Uncontrolled proximal thigh infection
• Failed transfemoral amputation (rare)

Considerations:

• Major operation with high morbidity
• High mortality in vascular patients (greater than 50%)
• Energy expenditure greater than 200% increase
• Most patients wheelchair-dependent

Technique (Key Points):

1. Anterior racquet incision from ASIS around hip
2. Divide sartorius, rectus femoris, hip flexors
3. Ligate femoral artery and vein
4. Divide adductors, iliopsoas
5. Disarticulate hip joint - divide ligamentum teres
6. Divide gluteal muscles and sciatic nerve
7. Close gluteus maximus over acetabulum
8. Layered closure

Postoperative:

• ICU monitoring often required
• High transfusion requirements
• Early mobilization in wheelchair
• Canadian-type hip disarticulation prosthesis available

Wound-Related Complications

Revision Rates by Level:

• Toe/Ray: 30-50% in vascular disease
• TMA: 20-40%
• Transtibial: 10-20%
• Transfemoral: 5-10%

Key Point: More distal amputations have higher revision rates but better function if successful.

Complications by Amputation Level

Toe/Ray Amputation:

• Transfer ulcers on remaining toes
• Wound dehiscence
• Progression of vascular disease

Transmetatarsal:

• Equinovarus deformity (unopposed triceps surae)
• Stump tip ulceration
• Failure to heal

Syme Amputation:

• Heel pad migration
• Dog-ear deformity
• Posterior wound breakdown

Transtibial:

• Flexion contracture of knee
• Anterior skin breakdown (bevel inadequate)
• Fibular pressure symptoms (fibula too long)

Transfemoral:

• Abduction contracture (inadequate adductor myodesis)
• Flexion contracture of hip
• Phantom limb pain

Prevention and Management of Contractures

Knee Flexion Contracture (Transtibial):

• Prevention: Prone lying, stretching, avoid pillow under knee
• Early: Stretching, serial casting
• Established: May require surgical release

Hip Flexion Contracture (Transfemoral):

• Prevention: Prone lying 30 min twice daily, positioning
• Keep hip extended when possible
• Avoid sitting for prolonged periods

Hip Abduction Contracture (Transfemoral):

• Prevention: Adductor myodesis during surgery
• Treatment: Difficult - prosthetic modification

Equinovarus (TMA):

• Prevention: Achilles lengthening, AFO use
• Treatment: TAL, casting, revision surgery

Phantom Limb Pain and Residual Limb Pain

Phantom Limb Pain (PLP):

• Incidence: 70-80% of amputees
• Painful sensations in absent limb
• Character: Burning, shooting, cramping, stabbing

Risk Factors:

• Preoperative pain (strongest predictor)
• Traumatic amputation
• Psychological distress

Management:

1. Pharmacological: Gabapentinoids, TCAs, SNRIs
2. Mirror therapy: Strong evidence - visual feedback
3. TENS: Transcutaneous electrical stimulation
4. Psychological support: CBT, counseling

Residual Limb Pain:

• Pain in actual stump (not phantom)
• Causes: Neuroma, bone spur, infection, poor socket fit
• Treatment: Address underlying cause

Neuroma Management:

• Desensitization techniques
• Injection therapy (local anesthetic, steroid)
• Surgical revision if refractory

Global Epidemiology

Worldwide, the dominant causes of major lower limb amputation are peripheral arterial occlusive disease (PAOD) and diabetic foot disease; trauma, malignancy and congenital deformity account for the remainder and predominate in younger patients. A GBD-2017 analysis of EU15+ countries (Hughes et al., 2020) found that despite a falling incidence of PAOD, trends in lower extremity amputation incidence were highly variable between countries and did not consistently decline. Australia recorded the highest age-standardised incidence rates for all amputation categories at every time point and the greatest overall increase, whereas the USA achieved the largest reductions over 1990 to 2017.

Guideline Comparison

Registry Evidence and Practice Variation

National vascular and amputation registries (for example UK National Vascular Registry/NVR audits, Vascunet collaborations and the SerbVasc registry) consistently report that major amputation carries high perioperative mortality - in-hospital mortality after above-knee amputation is frequently around 10% - and that only a minority of patients undergo revascularisation before amputation. Registry data also reveal wide practice variation in the ratio of major to minor amputations and in transtibial-versus-transfemoral selection between centres, much of which reflects case mix, access to revascularisation and multidisciplinary footcare rather than surgical preference alone.

• Health-equity gradients are marked: across high-income settings, disadvantaged and minority populations — including Indigenous peoples (for example Aboriginal and Torres Strait Islander Australians, who experience substantially higher diabetes-related amputation rates than non-Indigenous Australians) and comparable groups internationally — carry a disproportionate amputation burden. This reflects disparities in diabetes prevalence, access to multidisciplinary foot care and timely revascularisation rather than biological differences, and targeted, culturally safe prevention and foot-protection services narrow the gap.