What should be done for a concern at the bottom of a right Below-Knee Amputation (BKA) stump?

Management of Right Below-Knee Amputation (BKA) Stump Concerns

For any concern at the bottom of a right BKA stump, immediately assess for skin breakdown, infection, or prosthetic-related trauma, and modify or discontinue prosthetic use based on the specific pathology identified. 1

Initial Assessment Priorities

Examine for Common Stump Pathologies

• Blisters or friction injuries: The bottom of the stump is a weight-bearing surface highly susceptible to mechanical trauma from prosthetic use 1
• Ulceration: Stump ulcers occur commonly in amputees and require specific management protocols 2
• Infection signs: Look for erythema, warmth, purulent drainage, or fistula formation, as stump sites represent an "immunocompromised district" prone to infection 3
• Adherent or wrinkled scars: These occur in 13% of BK stumps and can cause breakdown, particularly at pressure points 4

Critical Clinical Context

• Location matters significantly: The British Journal of Dermatology specifically identifies "below the knee" as a site where poor healing is a particular concern, and all treatment modalities can lead to ulceration 5
• Stump skin vulnerability: Unlike volar skin on palms/soles, stump skin is not adapted to withstand compressive forces from prosthetics, making the weight-bearing bottom surface especially prone to breakdown 3

Management Algorithm Based on Pathology

If Blisters Are Present

Lance blisters immediately with a sterile needle at the lowest point to facilitate gravity drainage 1

• Leave the blister roof in place as a biological dressing to prevent secondary infection 1
• Use gauze or absorbent material to wick fluid from the blister 1
• Apply low-adhesion dressings over painful eroded areas, secured with soft elasticated viscose 1
• Critical pitfall: Do NOT leave large blisters intact on weight-bearing surfaces like the stump bottom—they will enlarge and worsen with prosthetic use 1

If Ulceration Is Present

Most patients can continue controlled prosthetic use during ulcer healing, but this requires careful monitoring 2

• Wound dressing selection based on ulcer characteristics 5:
  • Hydrogels for dry/necrotic wounds
  • Alginates or foams for exudative wounds
  • Hydrocolloids for absorbing exudate
• Consider saline soaks and topical antiseptics (potassium permanganate baths or antiseptic bath oils) for a few days to dry lesions and prevent infection 1
• A study of 94 amputees with stump ulcers found that 64% healed completely within 6 weeks despite continued prosthetic use, with only 9% showing deterioration 2
• Elevation and compression bandaging should be advised where possible, as poor healing is a particular concern below the knee 5

If Infection Is Suspected

• Implement antiseptic measures immediately: topical antiseptics or antibiotics until skin heals 1
• If fistula formation is present, consider laser ablation as a minimally invasive alternative to multiple surgical interventions 6
• Assess for deeper infection requiring systemic antibiotics, particularly in diabetic or vascular disease patients 5, 3

Prosthetic Modifications to Prevent Recurrence

Prosthetic socket assessment and modification are essential to prevent ongoing trauma 1

• Use lightweight prosthetic materials and soft padding to reduce trauma and facilitate weight bearing 1
• Implement shock-absorbing insoles and custom orthotics to reduce friction and improve mobility 1
• Ensure proper socket fit with adequate cushioning to minimize friction and mechanical trauma 1
• Consider silver-lined socks to reduce moisture and friction 1
• Assess weight distribution and gait patterns to identify the source of excessive friction causing bottom-of-stump pathology 1

High-Risk Patient Considerations

Factors Increasing Reoperation Risk

• Recent smokers have 1.34 times increased risk of reoperation (p=0.02) 7
• Bleeding disorders increase risk by 1.30 times (p=0.02) 7
• Patients transferred from another facility have 1.28 times increased risk (p=0.04) 7
• Overall reoperation rate after BKA is 9.63%, with 30-day mortality of 5.14% 7

Vascular Disease Patients

• For patients with underlying vascular disease, assess for critical ischemia that may impair healing 5
• Revascularization should be performed early rather than delaying for prolonged antibiotic therapy if severe infection with ischemia is present 5

When to Discontinue Prosthetic Use

Temporary prosthetic discontinuation is indicated when 2:

• Active infection with systemic signs
• Rapidly deteriorating ulceration despite modifications
• Extensive necrosis requiring surgical debridement 5

However, recognize that prosthetic abandonment negatively impacts quality of life, so the threshold for complete discontinuation should be high 3