Amputation Types in Surgery

Definitions

• Toe amputation involves division of the phalynx or disarticulation of the metatarsal-phalangeal joint.
• Ray amputation involves removal of the corresponding metatarsal.
• Transmetatarsal amputation involves partial foot amputation through the metatarsals.

Principles

• Remove all infected, gangrenous, ischaemic tissue.
• Preserve length and wound that heals successfully, leaving a functional limb.
• Avoid repeated amputations, "funny feet", and non-healing operative sites.
• Technical principles include fashioning adequate flaps, dividing bone proximal to muscle, beveling bone, performing myoplasty, achieving hemostasis, and using atraumatic skin approximation.

Toe Amputation Principles

• Conserve function and as much tissue as possible.
• Partial amputation of a toe keeps the adjacent toes in normal alignment.
• The head of the 1st metatarsal (hallux) is important in weight-bearing and should be spared.
• Amputation through a phalange is better than disarticulation, preserving tendon attachments at the base of the phalynx.

Toe Amputation

• The hallux is important for balance and walking because it provides push-off.
• The 2nd toe acts as a lateral support for the hallux, and its amputation may lead to hallux valgus.
• The transverse arch gets affected with any toe amputation.

Post-Operative Care

• Weight-bearing is prohibited if a formal amputation is performed until wound healing has been achieved.

Mid and Hindfoot Amputations

• Types include Lis Franc, Chopart, and Symes.
• Advantages include preservation of length and epiphyseal plate in children.
• Disadvantages include wound breakdown and cosmesis.
• Complications include equinus deformity due to imbalance in gastroc-soleus and dorsiflexion.

Below Knee Amputation

• The ideal BKA stump should be 1/3 the length of the tibia, with the fibula cut higher to avoid diastasis and erosion through the skin.
• There should be no flexion contractures, and the nerves should be divided under tension to avoid neuroma in scar tissue.

Energy Expenditure

• Amputation level and energy expenditure above baseline (%) are related: long transtibial (BKA) 10%, average transtibial (BKA) 25%, short transtibial 40%, bilateral transtibial 41%, and transfemoral (AKA) 65%.

Wound Healing

• Failure to heal amputation is multifactorial, with causes including ischaemia, infection, haematoma, and trauma.
• Predictors of wound healing include assessing blood flow at the level of amputation, with TcPO2 demonstrated to be the most accurate predictor.

Introduction

• Despite advances in revascularization, lower extremity amputation remains a common procedure in modern vascular practice.
• Peripheral vascular disease (PVD) alone or with diabetes accounts for >50% of amputations, with an incidence of 12-50 per 100,000/year according to the TASC II working group.

Basic Anatomy

• Forefoot: 5 toes + metatarsals.
• Midfoot: arches of the foot (tarsal bones).
• Hindfoot: heel + ankle.

Indications

• Elective indications include peripheral arterial disease, complications of diabetes mellitus, failed limb salvage, and failed minor amputation.
• Emergency indications include trauma and life-saving decisions.

Classification

• Minor amputations are below the ankle (toe, transmetatarsal).
• Major amputations are above the ankle (below knee, through knee, above knee, hip disarticulation).

Types of Amputation

• Guillotine and formal amputations are two types of amputation.

Staged Amputations

• Local study: important for diabetics, with advantages including improved healing and disadvantages including 2 operations in high-risk patients.

Antibiotics

• Prophylactic antibiotics are used to cover broad-spectrum aerobic, perineal, and Gram-positive organisms (Staph).

Soft Dressings

• Advantages include ease of application, low cost, and wound accessibility.
• Disadvantages include decreased skin perfusion, knee contracture, poor pain control, and decreased mobility.

Complications

• Neuroma can be avoided by cutting nerve sharply under tension.

Rehabilitation

• Phase 1 includes avoiding contractures, physiotherapy (passive movements and isometric exercises), and exercises.
• Phase 2 includes standing and balancing exercises, parallel bars, and inflatable prosthetics, as well as endurance exercises if needed.

Amputations

Indications

• Lower extremity amputation remains a common procedure in modern vascular practice
• PVD alone or with Diabetes account for >50% of amputations
• Trauma is the 2nd leading cause
• Amputation is a definitive treatment option, despite being viewed as a failure of treatment
• 50-75% of amputees die within 5 years

Basic Anatomy

• Forefoot: 5 toes + metatarsals
• Midfoot: arches of the foot (tarsal bones)
• Hind foot: heel + ankle

Classification

• Minor (below the ankle): toe, transmetatarsal
• Major (above the ankle): below knee amputation (BKA), through knee amputation (TKA), above knee amputation (AKA), hip disarticulation

Types of Amputation

• Guillotine
• Formal

Staged Amputations

• Important for diabetics
• Advantage: healing improved
• Disadvantage: 2 operations in high-risk patients

Definitions

• Toe amputation: involves division of the phalynx or disarticulation of the metatarsal-phalangeal joint
• Ray amputation: removal of the corresponding metatarsal
• Transmetatarsal amputation: partial foot amputation through the metatarsals

Principles

• GENERAL:
  • Remove all infected, gangrenous, ischaemic tissue
  • Preserve length
  • Wound that heals successfully - leaving a functional limb
  • Avoid repeated amputations, “funny feet”, and non-healing operative sites
• TECHNICAL:
  • Fashion adequate flaps
  • Bone divided proximal to muscle
  • Bevel bone
  • Myoplasty
  • Haemostasis
  • Atraumatic skin approximation

Toe Amputation

• Conserve function and as much tissue as possible
• Partial amputation of a toe keeps the adjacent toes in normal alignment
• The head of the 1st metatarsal (hallux) is important in weight-bearing and should be spared
• Amputation through a phalange is better than disarticulation

Mid and Hindfoot Amputations

• Lis Franc, Chopart, Symes
• Advantage: preservation of length and epiphyseal plate in children
• Disadvantages: wound breakdown, cosmesis
• Complications: equinous deformity due to imbalance in gastroc-soleus and dorsiflexion

Below Knee Amputation

• Should be scar-free
• Ideal BKA stump:
  • 1/3 the length of the tibia
  • The fibula should be cut higher as it is prone to diastasis and erosion through the skin
  • No flexion contractures
  • Nerves should be divided under tension to avoid neuroma in scar tissue

Energy Expenditure

• Amputation level affects energy expenditure
• Long transtibial (BKA): 10%
• Average transtibial (BKA): 25%
• Short transtibial (BKA): 40%
• Bilateral transtibial (BKA): 41%
• Transfemoral (AKA): 65%
• Wheelchair: 0-8%

Wound Healing

• Failure to heal amputation is multifactorial
• Causes: ischaemia, infection, haematoma, trauma
• Predictors of wound healing:
  • Emphasis on assessing blood flow at level of amputation
  • TcPO2 demonstrated to be most accurate predictor of wound healing
• Antibiotics: prophylactic antibiotics are important for wound healing

Complications

• Neuroma: avoid by cutting nerve sharply and under tension