- See:
- BKA Prosthesis
- Amputations in the Diabetic Patient
- Pediatric BKA:
- Discussion:
- length considerations:
- ideal bone length is between 12 to 17 cm as measured from the medial joint line;
- in stumps less than 9 cm, consider removing the entire fibula along w/ some muscle bulk;
- when stump measures less than less than 5 cm, function is comprimised, therefore consider amputation at next higher level (knee disarticulation or AKA);
- gait and energy adaptions:
- average BK amputee expends about 40% more kcal/min than non amputees to maintain a normal gait;
- since the average BK amputee walks 36% slower, the average rate of oxygen consumption may remain unchanged;
- note, however, the net oxygen demand will increase since the total amount of work to walk a given distance will increase;
- references:
- Below knee amputation and rehabilitation of amputees.
- Gait kinematics in below-knee child amputees: a force plate analysis.
- vascular considerations: (anastomoses of lower limb arteries)
- dominant supply of the skin at this level is provided by the arteries that run w/ the saphenous nerve and the sural nerve (ie sural artery);
- references:
- Fasciocutaneous blood supply in below-knee amputation.
- Anatomical aspects of the blood supply to the skin of the posterior calf: technique of below-knee amputation.
- The blood supply to the skin of the leg: a post-mortem investigation.
- Segmental transcutaneous measurements of PO2 in patients requiring below-the-knee amputation for peripheral vascular insufficiency.
- Cutaneous blood flow and its relation to healing of below knee amputation.
- Muscle blood flow after amputation. Increased flow with medullary plugging.
- The below-the-knee amputation for vascular disease.
- Functional outcome of below-knee amputation in peripheral vascular insufficiency. A multicenter review.
- Noninvasive determination of healing of major lower extremity amputation: the continued role of clinical judgment.
- An index of healing in below-knee amputation: leg blood pressure by Doppler ultrasound.
- Diabetic Foot - Treatment Considerations
- 5-7 year mortality rate after BKA is greater than 50%;
- indications for BKA w/ chronic foot and ankle pain:
- in the report by Honkamp et al, the authors assessed the outcome of below-the-knee amputations performed to relieve intractable foot and ankle pain;
- patients with diabetes mellitus, peripheral vascular occlusive disease, or peripheral neuropathy were excluded;
- 20 patients met the inclusion criteria, and 18 completed the study;
- when asked whether they would have the BKA done again under similar circumstances, 16 patients said yes, one was unsure, and one said no;
- same distribution was observed when patients were asked if they were satisfied with the outcome: - 16 said yes, one was unsure, and one said no;
- after the amputation, the patients reported a decrease in both pain frequency and pain intensity;
- 10 patients discontinued the use of narcotics, and seven decreased the level and/or dosage;
- 3 patients worked before the amputation, and eight worked after the amputation;
- average walking distance increased from 0.3 to 0.8 mile (p = 0.0034).
- ref: Retrospective Review of Eighteen Patients Who Underwent Transtibial Amputation for Intractable Pain.
- considerations with gangrene and infection: (debridment of muscle)
- references:
- Lower extremity amputation: open versus closed.
- One-stage versus two-stage amputation for wet gangrene of the lower extremity: a randomized study.
- Simplified two-stage below-knee amputation for unsalvageable diabetic foot infections.
- Staged below-knee amputations for septic peripheral lesions due to ischaemia.
- Guillotine amputation in the treatment of nonsalvageable lower-extremity infections.
- Primary closure of below-knee amputation stumps: a prospective study of sixty-two cases.
- Below knee amputation in war surgery: a review of 111 amputations with delayed primary closure.
- Below-knee amputation for ischaemic gangrene. Prospective, randomized comparison of a transverse and a sagittal operative technique.
- Technical Considerations:
- posterior flap technique:
- osteomyoplastic technique:
- Osteomyoplastic and Traditional Transtibial Amputations in the Trauma Patient: Perioperative Comparisons and Outcomes
- skew flap:
- level of bone section about 10-15 cm below the tibial plateau
- shortest level that can be accepted allows 3 cm of stump below the flexor tendons when the knee is 90 deg flexed
- point is drawn on the skin 2.5 cm lateral to the subcutaneous crest of tibia & this is point of anterior insection of two flaps;
- use a measuring tape to mark the posterior flap;
- long and short saphenous veins are identified and ligated;
- saphenous nerve and sural nerve are carefully separated, pulled down & divided under tension so that they will not be incorporated into ligatures securing the veins;
- references:
- Long posterior flap versus equal sagittal flaps in below-knee amputation for ischaemia.
- Skewflap versus long posterior flap in below-knee amputations: multicenter trial.
- Experience with the 'skew flap' below-knee amputation.
- A rationale for skew flaps in below-knee amputation surgery.
- Sagittal flaps in below-knee amputations in Chinese patients.
- Below-knee amputation using the sagittal technique: a comparison with the coronal amputation.
Below-knee amputation: a modern approach
A prospective study of lower limb amputations.
Doppler-determined segmental pressures and wound-healing in amputations for vascular disease.
Improved results with diabetic below-knee amputations.
Lower extremity amputation: the control series.
Iatrogenic tibial pseudoaneurysm following below-knee amputation.
Myodermal flap closure of below the knee amputation.
Wedge resection of amputation stumps. A valuable salvage procedure.