What are the common symptoms and complications in a patient with a history of diabetes or peripheral artery disease after undergoing a below the knee amputation?

Common Symptoms and Complications After Below-Knee Amputation in Diabetic and PAD Patients

Patients with diabetes or peripheral artery disease who undergo below-knee amputation face a constellation of complications including wound healing problems (occurring in 18-45% of cases), phantom limb pain, stump infections, readmission within 30 days (occurring in 18-26% of cases), and a 30-day mortality risk of 7%, with long-term outcomes showing poor quality of life and high rates of contralateral limb loss. 1, 2, 3

Immediate Post-Operative Complications

Wound Healing Problems and Infections

• Wound complications occur in 18-45% of patients, representing the most common post-amputation problem, with higher rates in those with contaminated or infected wounds at the time of surgery 2, 3
• Serosanguinous drainage from the stump is common and requires careful assessment to distinguish normal post-operative drainage from infection or abscess formation 4
• Wound infections develop in approximately 9.3% of patients within 30 days, often requiring return to the operating room (15.6% of cases) 2
• Deep space infections and retained purulence may necessitate urgent surgical debridement 5

Systemic Complications

• Postoperative sepsis occurs in 9.3% of patients, particularly in those with pre-existing sepsis, representing a life-threatening emergency 2
• Acute kidney injury and volume depletion can develop, especially in patients with pre-existing renal insufficiency 5, 2
• The 30-day mortality rate is 7%, with independent predictors including renal insufficiency, cardiac disease, history of sepsis, steroid use, COPD, and advanced age 2

Pain Syndromes

Phantom Limb Pain

• Phantom limb pain is a poorly understood but common complication affecting amputated limbs, requiring early recognition and management 6
• Effective management of established phantom pain remains a major clinical challenge, though early physiotherapy intervention shows promise in reducing its severity 6, 7

Stump Pain

• Residual limb pain requires desensitization techniques and careful wound management as part of comprehensive rehabilitation 7

Functional and Quality of Life Outcomes

Mobility and Independence

• Walking with a prosthesis and resumption of ambulation are the two outcomes with the greatest impact on quality of life among amputees 1
• Approximately 83% of patients are ambulatory at discharge, though this requires intensive rehabilitation 8
• Below-knee amputation provides superior functional outcomes compared to above-knee amputation, making preservation of the knee joint critical 1

Factors Associated with Lower Quality of Life

• Age >65 years, presence of diabetes, and social isolation (being homebound) are major factors reducing quality of life after amputation 1
• Female sex, especially if age <60 years, is associated with lower quality of life outcomes 1
• Impaired ambulatory status at presentation predicts worse outcomes (hazard ratio 6.44) 1

Long-Term Complications and Prognosis

Wound Recurrence and Contralateral Limb Threat

• Patients require customized follow-up care including local wound care, pressure offloading, serial foot biomechanics evaluation, and therapeutic footwear to prevent wound recurrence 1
• The contralateral limb remains at high risk, particularly in patients with diabetes and neuropathy who have had critical limb-threatening ischemia 1

Hospital Readmission and Reintervention

• Readmission within 30-60 days occurs in 18-26% of patients, with reintervention within 3 months and readmission within 6 months occurring in over half of patients 1, 2, 3
• Wound healing complications, infection, and cardiovascular events drive these readmissions 2, 3

Mortality

• Five-year mortality after diabetic foot ulcer with PAD is approximately 50%, similar to some of the most deadly cancers, reflecting the burden of advanced cardiovascular disease 9
• The presence of end-stage renal disease (hazard ratio 2.48), infrainguinal disease (hazard ratio 3.93), and gangrene at presentation (odds ratio 2.40) independently predict failure 1

Critical Management Considerations

Multispecialty Team Approach

• Evaluation by a multispecialty care team is essential to assess healing potential, provide maximal functional ability, and manage the complex medical comorbidities in this population 1
• Team members should include vascular surgery, infectious disease, endocrinology, podiatry, physical medicine and rehabilitation, and wound care specialists 1, 5

Stump Management

• Removable rigid dressings (RRDs) are superior to soft dressings alone for post-operative management, as they allow regular wound inspection, reduce edema, prevent knee flexion contractures, and protect from trauma 4
• Daily monitoring of drainage volume, character, and associated symptoms is necessary 4

Early Rehabilitation

• Physiotherapy should begin on the second postoperative day, emphasizing wound care, edema management, pain relief, and early mobilization 7
• Pre-prosthetic training includes strengthening, range of motion exercises, and residual limb desensitization 7

Common Pitfalls to Avoid

• Never assume adequate perfusion based on palpable pulses alone—up to 50% of diabetic foot ulcer patients have PAD despite seemingly adequate examination findings 9
• Avoid superficial wound swabs for culture as they may be misleading and promote unnecessarily broad antibiotic treatment 4
• Do not delay vascular assessment or revascularization evaluation, as even post-amputation patients may benefit from optimization of perfusion to the stump 1
• Recognize that diabetes, renal disease, cardiac issues, history of sepsis, steroid use, contaminated wounds, and alcohol use are independent predictors of complications requiring heightened surveillance 2