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http://upload.orthobullets.com/topic/1052/images/wrist disarticulation.jpg
http://upload.orthobullets.com/topic/1052/images/transradial.jpg
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Introduction
  • May be used to treattrauma
    • infection
    • tumor
    • vascular disease
    • congenital anomalies
  • Prognosis
    • outcomes are improved with involvement of psychological counseling for coping mechanisms 
    • amputation vs. reconstruction 
      • LEAP study
        • impact on decision to amputate limb
          • severe soft tissue injury
            • highest impact on decision-making process
          • absence of plantar sensation
            • 2nd highest impact on surgeon's decision making process
            • not an absolute contraindication to reconstruction
            • plantar sensation can recover by long-term follow-up
        • outcome measure
          • SIP (sickness impact profile) and return to work not significantly different between amputation and reconstruction at 2 years in limb-threatening injuries
          • most important factor to determine patient-reported outcome is the ability to return to work 
Metabolic Demand
  • Metabolic cost of walking
    • increases with more proximal amputations  
      • perform amputations at lowest possible level to preserve function
      • exception
        • Syme amputation is more efficient than midfoot amputation
    • inversely proportional to length of remaining limb
  • Ranking of metabolic demand (% represents amount of increase compared to baseline)
    • Syme - 15%
    • transtibial
      • traumatic - 25% average
        • short BKA - 40%
        • long BKA - 10%
      • vascular - 40%
    • transfemoral
      • traumatic - 68%
      • vascular - 100%
    • thru-knee amputation
      • varies based on patient habitus but is somewhere between transtibial and transfemoral
      • most proximal amputation level available in children to maintain walking speeds without increased energy expenditure compared to normal children 
    • bilateral amputations
      • BKA + BKA - 40% 
      • AKA + BKA - 118%
      • AKA + AKA - >200%
Wound Healing
  • Dependent on
    • vascular supply
    • nutritional status
    • immune status
  • Improved with
    • albumin > 3.0 g/dL 
    • ischemic index > .5
      • measurement of doppler pressure at level being tested compared to brachial systolic pressure
    • transcutaneous oxygen tension > 30 mm Hg (ideally 45 mm Hg)
    • toe pressure > 40 mm Hg (will not heal if < 20 mm Hg)
    • ankle-brachial index (ABI) > 0.45
    • total lymphocyte count (TLC) > 1500/mm3
  • Hyperbaric oxygen therapy
    • contraindications include
      • chemo or radiation therapy
      • pressure-sensitive implanted medical device (automatic implantable cardiac defibrillator, pacemaker, dorsal column stimulator, insulin pump) 
      • undrained pneumothorax
Upper Extremity Amputation
  • Indications
    • irreparable loss of blood supply
    • severe soft tissue compromise
    • malignant tumors
    • smoldering infection
    • congenital anomalies
  • Levels of amputation
    • wrist disarticulation versus transradial amputation
      • wrist disarticulation advantages
        • improved pronation and supination
        • recommended in children for preservation of distal radial and ulnar physes
        • longer lever arm
      • transradial advantages
        • more aesthetically pleasing
        • easier to fit prosthesis
    • transhumeral versus elbow disarticulation
      • elbow disarticulation advantages
        • indicated in children to prevent bony overgrowth seen in transhumeral amputations
  • Techniques
    • transcarpal
      • transect finger flexor/extensor tendons
      • anchor wrist flexor/extensor tendons to carpus
    • wrist disarticulation
      • preserve radial styloid flare to improve prosthetic suspension
    • transradial amputation
      • middle third of forearm amputation maintains length and is ideal
    • transhumeral amputation
      • maintain as much length as possible
    • shoulder disarticulation
      • retain humeral head to maintain shoulder contour
Transfemoral Amputation
  • Maintain as much length as possible
    • however, ideal cut is 12 cm above knee joint to allow for prosthetic fitting
  • Technique
    • 5-10 degrees of adduction is ideal for improved prosthesis function
    • adductor myodesis   
      • improves clinical outcomes
      • creates dynamic muscle balance
      • provides soft tissue envelope that enhances prosthetic fitting
Through-Knee-Amputation 
  • Indications
    • ambulatory patients who cannot have a transtibial amputation
    • non-ambulatory patients
  • Technique
    • suture patellar tendon to cruciate ligaments in notch
    • use gastrocnemius muscles for padding at end of amputation
  • Outcomes (based on LEAP data)
    • slower self-selected walking speeds than BKA 
    • similar amounts of pain compared to AKA and BKA
    • worse performance on the Sickness Impact Profile (SIP) than BKA and AKA
    • physicians were less satisfied with the clinical, cosmetic, and functional recovery
    • require more dependence with patient transfers than BKA
Below-Knee-Amputation (BKA)
  • Long posterior flap  
    • 12-15 cm below knee joint is ideal
      • ensures adequate lever arm
    • need approximately 8-12 cm from ground to fit most modern high-impact prostheses
    • osteomyoplastic transtibial amputation (Ertl) technique
      • create a strut from the tibia to fibula from a piece of fibula or osteoperiosteal flap
    • "dog ears"
      • left in place to preserve blood supply to the flap 
  • Modified Ertl 
    • designed to enhance prosthetic end-bearing 
    • technique
      • the original Ertl amputation required a corticoperiosteal flap bridge 
      • the modified Ertl uses a fibular strut graft
        • requires longer operative and touniquet times than standard BKA transtibial amputation
        • fibula is fixed in place with cortical screws, fiberwire suture with end buttons, or heavy nonabsorbable sutures. 
Ankle/Foot Amputation
  • Syme amputation (ankle disarticulation)
    • patent tibialis posterior artery is required 
    • more energy efficient than midfoot even though it is more proximal
    • stable heel pad is most important factor 
    • used successfully to treat forefoot gangrene in diabetics 
  • Pirogoff amputation (hindfoot amputation)
    • removal of the forefoot and talus followed by calcaneotibial arthrodesis
    • calcaneus is osteotomized and rotated 50-90 degrees to keep posterior aspect of calcaneus distal
    • allows patient to mobilize independently without use of prosthetic
  • Chopart amputation (hindfoot amputation)
    • a partial foot amputation through the talonavicular and calcaneocuboid joints
    • primary complication is equinus deformity  
      • avoid by lengthening of the Achilles tendon and transfer of the tibialis anterior to the talar neck  
  • Lisfranc amputation
    •  equinovarus deformity is common 
      • caused by unopposed pull of tibialis posterior and gastroc/soleus
      • prevent by maintaining insertion of peroneus brevis 
  • Transmetatarsal amputation  
    • more appealing to patients who refuse transtibial amputations
    • almost all require achilles lengthening to prevent equinus
  • Great toe amputations
    • preserve 1cm at base of proximal phalanx
      • preserves insertion of plantar fascia, sesamoids, and flexor hallucis brevis
      • reduces amount of weight transfer to remaining toes
      • lessens risk of ulceration
Complications
  • Wound healing
  • Postamputation Neuroma
    • treatment
      • targeted muscle reinnervation 
        • a method of guiding neuronal regeneration to prevent or treat post-amputation neuroma pain and improve patient use of myoelectric prostheses
  • Phantom limb pain
    • mirror therapy is a noninvasive treatment modality 
  • Bone overgrowth
    • most common complication with pediatric amputations 
      • treatment
        • prevent by performing disarticulation or using epihphyseal cap to cover medullary canal
 

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