Amputations
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Direct answer
Amputation — the removal of a limb through bone or joint — is indicated most often in India for diabetic foot sepsis and peripheral vascular disease, and otherwise for trauma, malignancy, crush injuries and rarely congenital deformity. Level selection balances viability and function: the most distal level with reliable perfusion and infection control is chosen, because a below-knee amputee commonly walks again whereas an above-knee amputee often cannot. Sound technique uses equal-length fish-mouth flaps (a long posterior myocutaneous flap below the knee), bevelling and shortening the fibula, cutting nerves sharply under tension so they retract, and leaving a rounded, non-adherent stump; in gross infection a guillotine amputation with delayed closure controls sepsis first. Phantom limb sensation is normal; phantom limb pain is a treatable neuropathic problem.
What you must remember
- Indications: ischaemia and diabetic sepsis (commonest in Indian practice), non-salvageable trauma, malignancy and overwhelming infection; level selection combines clinical perfusion with Doppler and transcutaneous oxygen studies.
- Below-knee amputation fashions a long posterior myocutaneous flap (the posterior calf has the better blood supply), with the fibula cut 1–2 cm shorter than the tibia to avoid pressure under the skin.
- Energy cost of walking (commonly quoted ranges): below-knee amputation roughly 10–40 per cent more than normal, above-knee roughly 50–100 per cent more — the reason knee preservation is fought for.
- Guillotine amputation — open division of all structures — controls sepsis, with formal closure after 48–72 hours; nerves are cut sharply under tension to retract away from the scar, and major vessels are ligated individually.
- Complications: stump pain from neuroma, infection or ischaemia, flexion contracture, adherent scar and psychological distress.
- Phantom limb sensation (non-painful awareness of the absent part) occurs in most amputees and needs reassurance; phantom limb pain is neuropathic, treated with gabapentinoids, amitriptyline, mirror therapy and, in selected cases, targeted muscle reinnervation.
- Prosthetics: a patellar-tendon-bearing prosthesis with supracondylar suspension for below-knee, and an ischial-bearing socket with suction or pelvic band for above-knee level.
Common confusion
Trainees equate 'amputate as low as possible' with 'preserve as much as possible'. An ischaemic marginal stump that breaks down condemns the patient to reoperation, so the level must respect perfusion, not length alone. The second confusion is phantom sensation versus phantom pain — the former is universal and benign, the latter a chronic pain syndrome needing treatment. Finally, a tender stump with a palpable nodule is a neuroma until proven otherwise, not 'normal healing'.
Exam-focused takeaway
Questions test the flap design for below-knee amputation, the fibula shortening rule, the energy-cost hierarchy (below-knee less than above-knee less than hip disarticulation), and the guillotine principle in infection. Stems describe a diabetic with spreading forefoot gangrene asking the level or the first-stage operation, or a post-amputation patient with burning stump pain asking the diagnosis (neuroma or phantom pain) and its management. Know that knee-joint preservation is the single strongest determinant of prosthetic walking.
Frequently asked questions
How is the level of amputation decided?
By viability and function together — clinical perfusion supplemented by Doppler and transcutaneous oxygen, infection localisation, and prosthetic potential.
Why is a long posterior flap used in below-knee amputation?
The gastrocnemius and soleus region carries the most reliable blood supply and provides durable soft-tissue padding over the tibial stump for weight transfer to the prosthesis.
How do phantom sensation and phantom pain differ?
Sensation is a non-painful awareness of the absent limb experienced by most amputees, whereas phantom pain is a genuine neuropathic pain syndrome treated with medication, desensitisation and reinnervation techniques.
Why preserve the knee joint whenever possible?
Because walking energy cost is far lower and prosthetic use far higher after below-knee than above-knee amputation, where most elderly vascular patients never regain functional ambulation.