What are the best practices for managing a patient undergoing an above knee amputation?

Best Practices for Managing Above Knee Amputation

When amputation is required, evaluation by a multispecialty care team is essential to determine the most distal level of amputation that facilitates healing and provides maximal functional ability. 1

Preoperative Assessment and Planning

Patient Evaluation

• Assess risk of amputation using objective classification tools (WIfI, GLASS) 1
• Evaluate patient's preoperative ambulatory status - strongest predictor of postoperative prosthetic use 2
• Consider age (patients >70 years have significantly poorer functional outcomes) 2
• Evaluate comorbidities, particularly:
  • Coronary artery disease
  • End-stage renal disease
  • Dementia
  • Diabetes mellitus 2

Amputation Level Decision Algorithm

1. Attempt limb salvage first if:

   • Patient is ambulatory before amputation
   • Age <60 years
   • No significant comorbidities
   • Revascularization options exist 1

2. Consider primary amputation when:

   • Life-threatening infection/sepsis exists
   • Extensive tissue destruction would result in nonfunctional extremity
   • Patient is non-ambulatory at baseline
   • Short life expectancy
   • Severe comorbidities make revascularization risky 1

3. Level selection:

   • Below-knee amputation: Preferred when possible for better mobility with prosthesis 1
   • Above-knee amputation: Consider when healing at lower level is unlikely
   • Through-knee amputation: Consider for non-ambulatory patients (97% healing rate) 3

Surgical Technique

Vascular Management

• Apply direct pressure with gauze as initial intervention for bone bleeding 4
• Use bone wax for cancellous bone bleeding when pressure is insufficient 4
• For identifiable vessels within bone, consider vessel ligation if accessible 4

Bypass Considerations

• If revascularization is attempted before amputation:
  • Use autogenous saphenous vein for bypasses when possible 1
  • The most distal artery with continuous flow should be used as origin for bypass 1
  • The tibial or pedal artery providing continuous outflow to foot should be used for distal anastomosis 1

Postoperative Management

Immediate Care

• Monitor for wound complications, particularly in patients with:
  • Diminished femoral pulse
  • Hypertension
  • Failed bypass procedure to the groin
  • Stenosis/occlusion of common femoral or profunda femoral artery 5
• Maintain adequate intravascular volume with crystalloid fluids 4
• Monitor hemoglobin/hematocrit to detect ongoing bleeding 4

Long-term Follow-up

• Implement antiplatelet therapy unless contraindicated 1
• Establish a customized program of follow-up care 1
• Perform clinical examination, ABI (or TBI) measurement, and DUS within 4-6 weeks and at 3,6,12, and 24 months after surgery 1
• Optimize management of diabetes and other medical comorbidities 1

Rehabilitation Considerations

Prosthetic Planning

• Patients with limited preoperative ambulatory ability, age ≥70, dementia, end-stage renal disease, and advanced coronary artery disease have poor prosthetic utilization 2
• Only 22% of patients with through-knee amputations for vascular disease go on to ambulate, with better outcomes in trauma patients and those under 50 years 6
• Below-knee amputees achieve 2-3 times better mobility than above-knee amputees 7

Functional Outcomes

• Approximately 30% of amputees will be dead within 2 years of a successful below-knee amputation 7
• 15% of below-knee amputees will require conversion to above-knee within 2 years 7
• 15% will require contralateral amputation within 2 years 7

Common Pitfalls to Avoid

• Attempting to save the knee joint in patients with poor healing potential
• Failing to consider through-knee amputation for non-ambulatory patients
• Not addressing inflow obstructions when treating downstream lesions 1
• Inadequate assessment of femoral pulse quality before above-knee amputation 5
• Neglecting long-term follow-up and surveillance for contralateral limb issues