overview Overview amputations are done urgently and electively to reduce pain, provide independence, and restore function the goals of amputation are preserve functional length preservation of useful sensibility prevention of symptomatic neuromas prevention of adjacent joint contractures early prosthetic fitting early return of patient to work and recreation Epidemiology Incidence 1.7 million individuals in the United States with an amputation Risk factors 80% of amputations are performed for vascular insufficiency Etiology Pathophysiology Amputations may be indicated in the following trauma most common reason for an upper extremity amputation infection tumor vascular disease most common reason for a lower extremity amputation congenital anomalies 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 Amputation versus limb salvage and replantation mangled upper extremity has a far greater impact on overall function than does a lower extremity amputation upper extremity prostheses have much more difficulty replicating native dexterity and sensory feedback provided by the native limb results of nerve repair and reconstruction are more successful in upper extremity than lower extremity superior functional outcomes can be expected in replanted limbs compared with upper extremity amputations diminishing outcomes from replantation are expected the more proximal the level, especially about the elbow Levels of amputation wrist disarticulation or transcarpal versus transradial amputation wrist disarticulation advantages improved pronation and supination recommended in children for preservation of distal radial and ulnar physes longer lever arm disadvantage can be difficult to use with highly functional prosthesis compared to transradial Although, this may be changing with advancing technology transradial advantages more aesthetically pleasing easier to fit prosthesis (myoelectric prostheses) transhumeral versus elbow disarticulation elbow disarticulation advantages indicated in children to prevent bony overgrowth seen in transhumeral amputations Techniques general All named motor and sensory branches within operative field should be identified and preserved can result in improved muscle mass and preserve the ability to create myoelectric signal for targeted reinnervation myodesis, the process of attaching the muscle-tendon unit directly to bone is recommended transcarpal transect finger flexor/extensor tendons anchor wrist flexor/extensor tendons to carpus wrist disarticulation preserve radial styloid flare to improve prosthetic suspension requires healthy and intact DRUJ transradial amputation middle third of forearm amputation maintains length and is ideal residual 5cm of ulna is required for elbow motion, but at this level will have limited pronation/supination transhumeral amputation maintain as much length as possible ideal level is 4-5cm proximal to elbow joint if more proximal amputation is required: At least 5-7cm of residual length is needed for glenohumeral mechanics shoulder disarticulation retain humeral head to maintain shoulder contour Targeted Muscle Reinnervation designed to improve control of myeolectric prostheses used for amputation general transfer amputated large peripheral nerves to reinnervated functionally expendable remaining muscles to create a new discrete muscle signal for the myoelectric prosthesis control secondary benefit of alleviating symptomatic neuroma pain Transfemoral Amputation Maintain as much length as possible however, ideal cut is 12 cm (10-15cm) 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 (otherwise have unopposed abductors) provides soft tissue envelope that enhances prosthetic fitting Gritti-Stokes amputation amputation through the femur near level of adductor tubercle synovium is excised to prevent postoperative effusion patella is arthrodesed to the end of femur for improved end bearing prepatellar soft tissue is maintained without iatrogenic injury improved outcomes as compared to transfemoral amputation 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 Consequence of poor soft tissue envelope from loss of gastrocnemius padding require more dependence with patient transfers than BKA Below-Knee-Amputation (BKA) Long posterior flap 12-15 cm below knee joint is ideal (10-16cm of residual tibia bone) ensures adequate lever arm longer than this gets into the achilles tendon which has a suboptimal blood supply and ability for soft tissue cushioning need approximately 8-12 cm from ground to fit most modern high-impact prostheses "dog ears" preventable with well-designed incision lines if present, left in place to preserve blood supply to the posterior flap Modified Ertl designed to enhance prosthetic end-bearing argument is that the bone bridge will enhance weight bearing through the fibula and increase total surface area for load transfer increased reoperation rates have been reported technique the original Ertl amputation required a corticoperiosteal flap bridge the modified Ertl uses a fibular strut graft requires longer operative and tourniquet 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 technique medial and lateral malleoli are removed flush with distal tibia articular surface the medial and lateral flares of the tibia and fibula are beveled to enhance heel pad adherence heel pad is secured to anterior tibia 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 or Boyd 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 leads to apropulsive gait pattern because the amputation is unable to support modern dynamic elastic response prosthetic feet Lisfranc amputation (midfoot amputation) equinovarus deformity is common caused by unopposed pull of tibialis posterior and gastroc/soleus prevent by maintaining insertion of peroneus brevis and performing achilles lengthening a walking cast is generally used for 4 week to prevent late equinus contracture Energy cost of walking similar to that of BKA 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 Contractures adjacent joint contractures are common prevent with early aggressive mobilization and position changes Heterotopic ossification more common in trauma-related setting Infection trauma-related amputation have an infection rate of around 34% Postamputation Neuroma occurs in 20-30% of amputees prevent with proper nerve handling at the time of procedure 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 occurs in 53-100% of traumatic amputations 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 Prognosis Outcomes are improved with the involvement of psychological counseling for coping mechanisms Involves a close working relationship between rehab physicians, prosthetists, physical therapists, as well as psychiatrists and social workers High rate of late amputation in patients with high-energy foot trauma 1st metatarsal fracture fracture involving all five metatarsals 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 25% infection rate mangled foot and ankle injuries requiring free tissue transfer have a worse SIP than BKA most important factor to determine patient-reported outcome is the ability to return to work About 50% of patients are able to return to work METALS study study focused on military population in response to LEAP study slightly better results in regard to patient-reported outcomes for the amputation group with a lower risk of PTSD more severe limbs were going into salvage pathway military population with better access to prostheses higher rates of return to vigorous activity in the amputation group