14 Amputations

10.1055/b-0040-176955

14 Amputations

Kevin Tetsworth and Vaida Glatt

Introduction

Relative roles of limb salvage and amputation after trauma remain controversial (▶ Fig. 14.1 ). Difficult choice reflects severity of the injury, patient’s expectations and demands, surgeon’s training and experience, and the capabilities and limitations of a particular institution. Many limbs can be saved with effort and huge investment (time and money); in some instances the patient would be better served with an early amputation. Amputation is an excellent reconstruction option and should never be considered a “failure of treatment.” Decision to amputate involves many factors and it is carried out after a thorough discussion between patients, their families, prosthetists, rehabilitation physicians, and surgeons. Most often the final decision involves consultation between two or more senior surgeons regarding the indications, treatment alternatives, and patient-specific considerations.

**Fig. 14.1** Mangled extremity, type 3B open tibia fracture with significant diaphyseal bone and soft-tissue loss. Highly complex and difficult decisions are required in determining whether to perform an early amputation or to proceed with limb salvage and reconstruction.

I. Preoperative Assessment

History and physical examination
1. Consider all the aspects related to patient: employment, education level, psychiatric issues/personality disorders, compliance, patient motivation, and quality of their social support network.
2. These factors are more closely related to outcome than anything surgeons do.
3. History of the injury.
4. Systemic factors:
  1. Comorbidities—blindness, Parkinson’s disease, obesity, dementia, stroke—consider end-bearing stump.
  2. Smoking.
5. Local factors—vascularity, scarring, and bony prominences.
6. Multiple limb involvement—introduces another level of complexity.
7. Pain—localized tenderness (neuroma, bursitis, or infection), dysesthesias or neurogenic pain that is characteristic of neuroma, suspicion of chronic regional pain syndrome (CRPS).
8. Medication use—opioid dependency and illicit drugs.
9. Range of motion (ROM) of knee, hip, elbow—assess for hip flexion and knee flexion contractures.
10. Strength of local muscles—knee flexion/extension, hip flexion/extension, hip abduction/adduction.
11. The single most important muscle for functional gait is hip extension.
Imaging
1. Routine radiographs are usually all that is necessary.
2. For vasculopaths, Doppler studies and an ankle–brachial index (ABI) can be used to assess vascular supply and the risk of wound healing insufficiency.
3. Computed tomography scans and magnetic resonance imaging both are useful when assessing tumors and chronic infections.
4. Nuclear medicine scans are generally not helpful.
5. Dual-energy X-ray absorptiometry scans to assess bone mineral density are very useful if osseointegration is an option.
Classification
1. Acute injuries—many classification systems exist but overall interobserver variability is poor and not typically helpful in prognosis. The extent of soft-tissue injury or loss may be the most predictive outcome regardless of which classification system is used.
2. Amputations—most often these are classified according to expected anatomic level:
  1. Upper limb (▶ Fig. 14.2 )—forequarter, shoulder disarticulation, transhumeral (above elbow), through elbow, transradial (below elbow), wrist disarticulation.
    
    Fig. 14.2 Upper extremity amputation options.
  2. Lower limb (▶ Fig. 14.3 and ▶ Fig. 14.4 )—hip disarticulation, transfemoral (above knee), through knee (knee disarticulation), transtibial (below knee), Syme’s, Boyd or Pirogoff (preserve a portion of the calcaneus and the attached heel pad; fuse this composite to the distal tibia), Chopart (through talonavicular and calcaneocuboid joints), Lisfranc (through the tarsometatarsal joints), transmetatarsal, metatarsophalangeal joint (▶ Fig. 14.5 ).
    
    Fig. 14.3 Lower extremity amputation options.
    
    Fig. 14.4 Foot amputation options.
    
    Fig. 14.5 (a–c) Racquet style incision for a toe amputation (metatarsophalangeal level).

II. Initial Management

Initial management steps
1. Polytrauma patients should follow advanced trauma life support (ATLS) principles (see Chapter 9, Polytrauma, for additional details on the ATLS protocol).
2. Thorough debridement and lavage in the operating room: evaluate the injury severity, hemostasis, remove all foreign or devitalized material, extend margins of wound for better visualization, and excise bone fragments completely stripped of soft tissue.
3. Assess for possible compartment syndrome.
4. Improve reduction and apply spanning external fixation and sterile dressings.
5. Consider consultation with Plastic Surgery, Vascular, and Trauma Units.
Limb salvage or early amputation
1. Preinjury status (education, income, social support) is more important than the injury or treatment.
2. Comparable outcomes with limb salvage or primary amputation.
3. Patients can confidently choose which route they prefer with the expectation of similar outcomes.
4. Delayed amputation can still lead to a good outcome and permits an initial attempt of limb salvage.

III. Definitive Management

Indications for immediate amputation
1. Traumatically amputated limb, or nearly so.
2. Severely injured limb beyond what could be reasonably reconstructed—subjective, and the “severity” reflects clinical acumen and experience of surgeons involved.
3. Limb completely avascular and vascular repair not possible.
4. Limb is the source of uncontrollable hemorrhage.
5. Limb is the source of life-threatening infection.
Relative indications for early amputation
1. Severe open injuries of the foot and ankle.
2. Degloving soft-tissue injuries of the foot with loss of the heel pad (▶ Fig. 14.6 ).
  
  Fig. 14.6 Degloving injury, skin avulsed from entire foot (arrow indicates exposed calcaneus).
3. Anticipated outcome will inevitably result in a stiff, painful, and nonfunctional foot or hand.
4. Extensive soft tissue and/or bone loss.
An insensate plantar surface is no longer considered a relative indication as long-term prospective studies have shown sensation may return and this does not appear to significantly affect functional outcome.
Indications for amputation for definitive late post-traumatic reconstruction
1. Recalcitrant nonunion.
2. Chronically/recurrently infected.
3. Dysvascular.
4. The focus of incapacitating neurogenic pain.
5. Significant neurologic deficit affecting the patient’s function.
6. Stiff/painful/deformed foot or hand.

IV. Surgical Principles

Metabolic cost of gait after amputation
1. Metabolic demand is measured as energy expenditure or oxygen consumption.
2. Depends on the level—inversely proportional to the length of the residual limb.
3. General attempt is to preserve as much length as possible.
4. Increased energy consumption relative to baseline (intact lower limbs):
  1. Syme: 15%.
  2. Below knee amputation (BKA; transtibial): vascular 40%, traumatic 25% (short residuum 40% or long residuum 10–15%).
  3. Above knee amputation (AKA; transfemoral): vascular 100%, traumatic 70%.
  4. Bilaterals:
    - i. BKA + BKA = 40%.
    - ii. BKA + AKA = 120%.
    - iii. AKA + AKA > 200%.
5. Almost 90% of bilateral above knee amputees are wheelchair bound within 2 years.
6. Unfortunately, stump length is most often dictated by soft tissues and local vascularity.
The ideal stump
1. Short stump lacks mechanical advantage necessary for gait and can slip out of the socket.
2. Long stump is also more difficult to fit with a prosthetic limb—adequate space is required to accommodate all the components necessary.
3. Optimum length (▶ Fig. 14.7 ):
  
  Fig. 14.7 Typical clinical appearance of a post-traumatic below knee amputation stump, 15 months after the injury. Extensive scarring and skin grafts complicate prosthetic fitting.
  1. For AKA, 15 cm above the knee joint line.
  2. For BKA, 10 cm below tibial tubercle or 15 cm below knee joint line:
    - i. A longer stump has mechanical advantages and length should be preserved when possible.
    - ii. The fibula is more mobile in longer stumps and may become symptomatic (post-traumatic):
      - Consider creating a formal tibiofibular synostosis (Ertl procedure).
      - More difficult and technically demanding.
      - It has been shown in military injuries to not affect outcome with higher complication rates.
    - iii. Minimum of 25 cm clearance to fit components for a prosthetic foot/ankle—longer stump is easier to achieve in a tall patient, difficult when patient is short.
4. Smooth, firm, and round or conical-shape end best fits a socket-mounted prosthetic limb.
5. Minimal scar or prominent bone.
6. Opposing muscle groups sutured together over the bone end (myodesis).
7. Soft tissue covers bone end and provides effective cushion to local trauma.
8. Soft tissue coverage well vascularized; stable, not mobile.
9. For the lower limb, scars should be positioned away from the end of the residuum.
10. For upper limb amputations, the scar can be terminal.
11. Nerves transected short, buried in muscle away from the end of the residuum.
Transtibial (below knee) amputation after trauma
1. The operative techniques described here encompass the major principles of amputation surgery and can be generally applied to most other locations and different levels as required.
2. Incisions:
  1. Guillotine—used in an emergency situation to control hemorrhage or infection; in general, preserve as much good soft tissue as possible for later definitive amputation.
  2. “Fish mouth”—simplest and least technically demanding incision.
  3. Extended posterior flap—best applied for a BKA (▶ Fig. 14.8 ).
    
    Fig. 14.8 Extended posterior flap: (a) intraoperative photograph of a completed transtibial amputation, prior to closure; (b) posterior flap trimmed of excess tissue and provisionally closed with subcuticular resorbable sutures; (c) postoperative photograph after closure completed with nylon sutures.
  4. “Racquet”—useful for amputation of digits (▶ Fig. 14.5 ).
3. Specific to transtibial (below knee) amputation (extended posterior flap):
  1. Supine, nerve block for pain control in perioperative period.
  2. Tourniquet to 250–275 Torr (mm Hg).
  3. Traditionally amputation site is hands breadth below the tibial tubercle:
    - i. Now it is more common to do a mid-tibial amputation.
    - ii. Prosthetists need 25 cm clearance from the ground to bottom of the stump.
    - iii. Middle third length a good balance—better mechanics and more strength.
4. As residuum gets longer it “scissors” more and can be symptomatic, particularly when there is prior diastasis between the tibia and fibula (as in a displaced pilon fracture).
5. Controversial, but young trauma patients may be best candidates for a “bone bridge” (Ertl) procedure.
6. Based on soft tissues and other issues, select a level: examine limb from lateral view, and estimate width of limb with a ruler (e.g., 16 cm); distal margin posterior soft-tissue flap should lie at a point (n + 1) cm distal (i.e., 17 cm).
7. Surgical approach for a BKA:
  1. Incisions: straight transverse anterior at level of expected bone cut—extend distally medial/lateral posterior to equator—through skin, SQ, fascia.
  2. Distal posterior—straight transverse at calculated level—through skin, SQ, fascia.
  3. Medially isolate saphenous vein and nerve.
  4. Traction on nerves and cut sharply—saphenous is the least problematic (Chapter 13, Acute Compartment Syndrome, ▶ Fig. 13.2 ).
  5. Do not cut nerve at same level as prosthetic limb will rest—needs to be 1 to 2 cm proximal.
  6. On lateral side find interosseous membrane.
  7. Slide a clamp under it, then transect anterior and lateral compartments with knife.
  8. Retract muscle distally, then expose neurovascular bundle—ligate tibialis anterior vessels and then identify the deep peroneal nerve—traction on nerve, cut and allow it to retract proximally.
  9. Cut the tibia with a power saw under saline irrigation; cut fibula 1 to 2 cm shorter.
  10. Use a bone hook to control the tibia and use an amputation knife on posterior surface.
  11. Directly on back of tibia and fibula—complete amputation, remove foot and distal tibia.
  12. Dissect between deep and superficial posterior compartments; this plane is easier to find medially.
  13. Neurovascular bundle stays with fascia of the deep compartment—dissect out completely.
  14. Open the sheath distally, split longitudinally—take entire nerve out, do not injure vein.
  15. Traction on nerve, transect sharply independent of vessels—retract 8 to 10 cm proximal.
  16. Transect neurovascular bundle and isolate artery and two veins—suture ligate peroneal vessels.
  17. All named vessels get two ties with 0 silk suture—stick tie distal, free tie more proximal.
  18. Do not use free ties alone because the pulsatile motion could loosen the suture.
  19. In case of patients with “throbbing pain” after amputation possibly from ligating peroneal nerve with vessels of anterior compartment—separate them and cut nerve independently.
  20. Identify sural nerve in midline posteriorly—pull out 15 cm and then transect under tension.
  21. Ligate small saphenous vein adjacent to sural nerve—generally large, tendency to bleed.
  22. Remove soleus as needed to facilitate closure, but leave thick fasciocutaneous flap.
  23. Bevel end of exposed bone with a saw and then bevel the two corners created, rasp edges.
  24. Release tourniquet, get hemostasis—many venous bleeders in soleus—suture ties useful.
  25. Complete myodesis with heavy suture to close posterior fascia to anterior periosteum; the myodesis can be completed through drill holes in the anterior tibial cortex for a more secure repair.
  26. Close the superficial subcutaneous layer with 2-0 absorbable sutures and the skin with 2-0 non-absorbable sutures, using Steri-Strips to augment the closure between sutures; then apply sterile dressings, plus/minus a removable cast.
Transfemoral (above knee) amputation
1. Fish mouth incision.
2. Transect anterior (quadriceps) and lateral musculature using principles described above.
3. Identify and isolate the femoral artery and vein, suture ligate as described above.
4. Apply traction to the femoral nerve, cut sharply and allow to retract proximally.
5. Pull traction and sharply transect the saphenous nerve allowing it to retract proximally.
6. Transect medial musculature (adductors, sartorius, gracilis) 5 to 10 cm distal to the anticipated femoral cut for later adductor myodesis.
7. Cut the femur ~ 15 cm proximal to the knee joint.
8. Transect the remaining posterior (hamstring) musculature.
9. Identify the sciatic nerve and place a single suture ligature; apply traction and sharply transect the sciatic nerve, allowing it to retract proximally.
10. Complete the adductor myodesis with heavy suture through drill holes in the distal femoral residuum; suture the posterior hamstring fascia to the anterior quadriceps fascia for additional soft-tissue coverage of the stump.