What symptoms and complications should a patient who has undergone a below the knee (BKA) amputation watch out for during the post-operative period?

Post-Operative Symptoms and Complications to Monitor After Below-Knee Amputation

Patients who have undergone below-knee amputation must vigilantly monitor for wound complications, which occur in approximately 10% of cases, with the highest risk period extending well beyond the typical 30-day postoperative window—up to one year. 1, 2

Immediate Post-Operative Warning Signs (First 30 Days)

Wound-Related Complications

• Surgical site infection (superficial or deep) presents with increasing pain, redness, warmth, purulent drainage, or foul odor from the stump 1, 3
• Wound dehiscence (separation of surgical edges) occurs in approximately 10% of BKA patients and requires immediate surgical attention 1, 4
• Excessive bleeding or hematoma formation at the amputation site, particularly if you have elevated INR or bleeding disorders 1, 5
• Necrotic tissue or blackened edges of the wound indicating inadequate blood supply 4

Systemic Infection Signs

• Fever, chills, or rigors suggesting systemic infection or sepsis 3
• Postoperative sepsis occurs in 9.3% of BKA patients and is a major cause of mortality 3
• Confusion or altered mental status in older patients, which may be the only sign of infection 3

Cardiovascular Complications

• Chest pain, shortness of breath, or irregular heartbeat as cardiac issues are independent predictors of mortality after BKA 3
• Myocardial infarction risk is elevated in this population due to underlying vascular disease 1

Renal and Metabolic Issues

• Decreased urine output or dark urine as renal insufficiency is a major predictor of both mortality and complications 3
• Worsening blood sugar control in diabetic patients, as hemoglobin A1c >8.1% increases reoperation odds 4.6-fold 2

Extended Post-Operative Period (30 Days to 1 Year)

Stump-Related Problems

• Persistent or worsening stump pain beyond expected post-surgical discomfort, which may indicate infection, ischemia, or bone complications 2, 5
• Delayed wound healing extending beyond 5-6 weeks, which postpones prosthetic fitting and increases fall risk 6
• Residual limb edema that persists beyond week 5-6 or suddenly worsens 6
• Phantom limb pain requiring pain management intervention 2

High-Risk Complications Requiring Immediate Attention

• Falls are the most catastrophic delayed complication, occurring in 20.6% of lower limb amputees (the highest rate among all hospitalized populations), causing lacerations, fractures, and wound dehiscence that may require revision surgery 6
• Signs of inadequate perfusion including cool stump, absent pulses proximally, or progressive tissue necrosis requiring revision to above-knee amputation 4, 5

Reoperation Warning Signs

• 38% of BKA patients require unplanned reoperation within one year, with median time to reoperation of 54 days 2
• The most common reasons for reoperation are progression to above-knee amputation (28.7%), debridement/secondary closure (25.6%), and revision leg amputations (10.3%) 5
• Only 12% of patients reach 30 days without requiring reoperation, emphasizing the need for extended vigilance 2

Specific Risk Factors Requiring Enhanced Monitoring

Patients at Highest Risk for Complications

• Uncontrolled diabetes (HbA1c >8.1%) requires aggressive glycemic management before and after surgery 2
• Active smokers have 1.34 times increased odds of reoperation and should be counseled on immediate cessation 5, 3
• Bleeding disorders increase reoperation risk 1.3-fold 5
• Patients requiring preoperative ventilator support have 2.38 times increased reoperation odds 5
• Renal insufficiency or dialysis dependence independently predicts both mortality and complications 3
• History of sepsis, steroid use, COPD, cardiac disease, or alcohol use all independently increase complication rates 3

Critical Pitfalls to Avoid

• Do not assume normal healing trajectory in diabetic patients—they require more frequent wound checks and earlier intervention for any concerning signs 2
• Do not dismiss persistent pain as "normal post-operative discomfort"—it may indicate infection, ischemia, or need for revision 2, 5
• Do not delay seeking care for minor wound changes—early intervention for infection or dehiscence can salvage the BKA level and prevent progression to above-knee amputation 4
• Do not underestimate fall risk—implement aggressive fall prevention strategies as falls can be catastrophic in this population 6
• Do not wait for fever to diagnose infection—chronic infections may present with pain alone without systemic signs 3

When to Seek Immediate Medical Attention

Contact your surgical team immediately for:

• Any wound opening, drainage, or increasing redness 1, 4
• Fever >38.5°C (101.3°F) or chills 3
• Sudden increase in pain not controlled by prescribed medications 2
• Cool or discolored stump 4
• Any fall or trauma to the residual limb 6
• Chest pain, severe shortness of breath, or confusion 3
• Decreased urine output or leg swelling on the opposite side 3