Back to Operative Surgery
General

Below-Knee Amputation (Transtibial)

Surgical technique guide for Below-Knee (Transtibial) Amputation - FRCS/FRACS exam preparation

Core Procedure
intermediate
By OrthoVellum Medical Education Team

Reviewed by OrthoVellum Editorial Team

Editorial maintenance, source checking, and correction workflow • Published by OrthoVellum Medical Education Team

Editorial boardMethodologyReview policyReport a correction
High-yield overview

Long posterior myocutaneous flap (Burgess) or skew flap | level ~12-15cm below tibial tuberosity | intermediate

Surgical Imaging

Imaging Gallery

Intraoperative calcaneal skin flap dissected and mobilised alongside the tibial stump
Intraoperative view of the transtibial amputation stump (proximal, cylindrical tibial bone end visible above) alongside the mobilised calcaneal skin flap (below) — a specialised flap permitting terminal weight-bearing.Credit: Livani B et al. via Open-i NIH (PMC) (CC BY PMC Open Access)
Transtibial stump with calcaneal flap held by Ilizarov circular external fixator at 3 months
Three months postoperative: calcaneal flap secured and compressed onto the tibial stump using an Ilizarov circular external fixator with K-wires, allowing controlled flap integration and early progressive loading.Credit: Livani B et al. via Open-i NIH (PMC) (CC BY PMC Open Access)
Well-healed transtibial amputation stump at 30 months follow-up
Thirty months postoperative: the transtibial stump shows a well-healed, rounded endpoint with smooth skin coverage from the calcaneal flap, demonstrating excellent long-term stump durability.Credit: Livani B et al. via Open-i NIH (PMC) (CC BY PMC Open Access)
Patient performing full terminal weight-bearing on the transtibial stump at 30 months
Functional outcome at 30 months: patient bearing full body weight directly on the transtibial stump without a prosthesis — the defining advantage of the sensate calcaneal flap, enabling painless terminal weight-bearing rehabilitation.Credit: Livani B et al. via Open-i NIH (PMC) (CC BY PMC Open Access)

Critical Danger Structures

Danger 1: Posterior Tibial & Peroneal Vessels

Posterior tibial and peroneal neurovascular bundles. Location: Deep posterior compartment, posterior tibial bundle behind tibia between FDL and tibialis posterior; peroneal vessels adjacent to fibula. Protection: Identify, doubly ligate and divide each pedicle individually under direct vision before muscle transection. Inadequate ligation causes rapid stump haematoma, wound dehiscence and may force a higher revision amputation.

Danger 2: Tibial & Common Peroneal Nerves

Tibial nerve (with its accompanying artery) and common peroneal nerve. Location: Tibial nerve in deep posterior compartment; common peroneal winds around the fibular neck proximally. Protection: Apply gentle distal traction, divide sharply with a fresh blade well proximal to the flap so the nerve retracts away from the weight-bearing scar. Ligate the artery accompanying the tibial nerve. Neglect causes symptomatic neuroma and stump/phantom pain.

Danger 3: Flap Necrosis in the Dysvascular Limb

Marginal flap perfusion. Location: Distal flap edge, especially the long posterior or anterior flap tip in critical ischaemia or diabetes. Protection: Select level on perfusion data (TcPO2, ABI, Doppler), handle flaps atraumatically with skin hooks, avoid crushing forceps, do not close under tension, and excise any dusky margin. Necrosis leads to dehiscence, infection and conversion to AKA.

Danger 4: Prominent Tibial Crest / Inadequate Bevel

Sharp anterior tibial crest. Location: Anterior cortex at the bone-end. Protection: Bevel the anterior tibia 45-60 degrees and round/smooth all edges with a rasp; divide the fibula 1-2cm shorter and bevel it. A square or spiked tibial end tents the flap, causes skin breakdown over the bone and prevents prosthetic socket tolerance.

Danger 5: Neuroma & Phantom Phenomena

Cut nerve ends (tibial, common peroneal, sural, saphenous). Location: All divided nerves at the stump. Protection: Traction neurectomy so the nerve end lies in well-padded muscle away from bone and scar; consider TMR/regenerative peripheral nerve interface in selected cases. Pre-emptive and perioperative analgesia reduce phantom limb pain. A tender neuroma in the scar cripples prosthetic use.

Mnemonic

STUMPSTUMP - Principles of a Good Transtibial Stump

Mnemonic

HEALHEAL - Wound Healing Predictors at the Chosen Level

Primary Indications

The Big Four ("Dead, Dangerous, Damaged, Damn nuisance")

  • Dysvascular / diabetic limb (the commonest by far): critical limb ischaemia with unreconstructable disease or failed revascularisation, and diabetic foot sepsis/gangrene. Peripheral vascular disease and diabetes account for the large majority of lower-limb amputations in older patients.
  • Trauma: non-salvageable mangled lower leg (failed limb salvage, prolonged warm ischaemia, segmental soft-tissue/bone loss). Decision aided by clinical judgement and shared decision-making rather than any single score in isolation.
  • Infection: life-threatening sepsis (necrotising fasciitis, gas gangrene, uncontrolled diabetic foot infection or chronic osteomyelitis unresponsive to debridement and antibiotics).
  • Tumour: when limb-sparing resection is not feasible or would leave a non-functional limb; also chronic intractable pain or a useless deformed limb.

Why BKA is Preferred Over AKA When Viable

  • Energy cost of gait: transtibial amputees ambulate with roughly a 25% increase in energy expenditure above normal, whereas transfemoral amputees require around 65% more - the knee joint is the single biggest determinant of efficient prosthetic walking.
  • Prosthetic rehabilitation: preserving the anatomical knee dramatically improves the proportion of patients who become independent prosthetic walkers, particularly the frail, elderly and dysvascular population in whom every extra metabolic demand matters.
  • Functional independence: lower fall risk, better balance and a higher likelihood of returning to community ambulation than with above-knee amputation.
  • Trade-off: this benefit only holds if the BKA level can heal - a non-healing BKA that converts to AKA is worse than a primary AKA, so level selection is the critical judgement.

Contraindications to a Transtibial Level

  • Inadequate perfusion at the proposed level (very low TcPO2, absent popliteal pulse with unreconstructable disease).
  • Knee flexion contracture or a non-functional knee that would preclude prosthetic use.
  • Extensive proximal soft-tissue loss, sepsis or tumour reaching the upper calf.
  • Non-ambulatory patient where a higher, more reliably healing level may be more pragmatic (individualised).

Pre-operative Optimisation

  • Vascular assessment and intervention: confirm inflow and decide whether revascularisation could lower the amputation level or improve healing before committing to a level.
  • Sepsis control: in wet gangrene or ascending infection, consider a staged guillotine amputation first to control sepsis before definitive flap-based closure.
  • Metabolic and nutritional optimisation: tight glycaemic control, correct anaemia, and address malnutrition - serum albumin and total lymphocyte count are practical, validated healing predictors.
  • Medical and anaesthetic work-up: these patients are frequently elderly with significant cardiac, renal and respiratory comorbidity; multidisciplinary peri-operative care reduces mortality.

Level Selection

  • Ideal length: approximately 12-15cm of tibia measured from the tibial tuberosity, classically described as a hand's breadth below the tuberosity (or roughly 2.5cm of bone length per 30cm of body height as a rough guide).
  • Minimum functional length: a stump shorter than about 8cm of tibia below the joint line gives a poor lever arm, is difficult to fit and is prone to flexion contracture; extremely short stumps may not be functionally superior to a knee disarticulation.
  • Maximum length: avoid an over-long stump distally because soft-tissue cover and perfusion are poorer in the lower third of the leg and the muscle bulk for padding is thinner.
  • Perfusion overrides geometry: in the dysvascular limb the level is ultimately dictated by where the flap will heal, not by the ideal cosmetic length.

Evidence Base

Flap Design - Long Posterior vs Skew Flap

  • Burgess long posterior myocutaneous flap: Burgess described the long posterior flap with myoplasty and immediate postsurgical prosthetic fitting; the gastrocnemius-based flap has a robust blood supply and remains the workhorse for dysvascular limbs.
  • Robinson (Kingsley Robinson) skew flap: designed with equal-length antero-medial and postero-lateral skew flaps based on the angiosomes/perforators to improve perfusion and produce a cylindrical stump.
  • Head-to-head RCT (Ruckley multicentre trial): randomised comparison of skew flap versus long posterior flap found no significant difference in primary stump healing - both are acceptable, and surgeon familiarity and local perfusion guide the choice.

Tourniquet in Dysvascular Limbs (Controversy)

  • A prospective comparative study (Wolthuis, 89 patients) showed a pneumatic tourniquet in transtibial amputation reduced intra-operative blood loss (haemoglobin fall 5.6% vs 14.8%) and transfusion requirement, and roughly halved the revision rate (14.3% vs 38.3%), without increasing wound-healing failure. Note this was a prospective non-randomised cohort, not an RCT, so the evidence is suggestive rather than definitive.
  • Despite this, many vascular and orthopaedic surgeons still avoid tourniquet in critical ischaemia, fearing further compromise of marginal flap perfusion - hence it remains a genuine point of debate to discuss in a viva.

Rigid Dressings & Early Rehabilitation

  • Burgess popularised the immediate postoperative rigid dressing and immediate/early postsurgical prosthetic fitting, allowing earlier mobilisation and oedema control.
  • Rigid removable dressings protect the stump, control oedema, may speed healing and reduce knee flexion contracture compared with soft dressings, and facilitate progression to weight-bearing.

Wound Healing Predictors (Why Level Selection Fails or Succeeds)

  • Arterial perfusion: a palpable popliteal pulse, ankle-brachial index and toe pressures reflect inflow to the flap; the long posterior flap's gastrocnemius supply makes it relatively forgiving in ischaemic limbs.
  • Transcutaneous oxygen pressure (TcPO2): measured at the proposed level, values above approximately 30-40 mmHg are associated with primary healing, while very low values predict failure. Skin perfusion and skin blood-flow studies historically supported the same principle.
  • Nutrition and immunocompetence: low serum albumin and a depressed total lymphocyte count are associated with non-healing and amputation in diabetic foot disease - correct where possible before surgery.
  • Glycaemia and infection: uncontrolled diabetes and active infection impair healing; both should be addressed before definitive closure.

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 68-year-old diabetic with critical limb ischaemia has unreconstructable disease and dry gangrene of the forefoot extending to the mid-foot. The popliteal pulse is palpable. How do you decide between a below-knee and an above-knee amputation, and how do you select the level?"

PRACTICAL APPROACH
My overriding aim is to preserve the knee if the limb can heal at a transtibial level, because the knee is the single most important determinant of successful prosthetic rehabilitation. Transtibial amputees walk with roughly a 25% increase in energy cost compared with about 65% for transfemoral amputees, and far more BKA patients become independent walkers - which matters enormously in an elderly dysvascular patient with limited cardiorespiratory reserve. So my default is to attempt a BKA provided I judge it will heal. The decision therefore hinges on perfusion and healing potential at the proposed level, not on cosmesis. I would assess the vascular supply clinically (he has a palpable popliteal pulse, which is encouraging), with ankle-brachial and toe pressures, and ideally transcutaneous oxygen pressure - a TcPO2 above roughly 30-40 mmHg at the proposed level predicts primary healing. I would optimise glycaemic control, treat any infection, and assess nutrition since serum albumin and lymphocyte count predict healing. I would also confirm there is no fixed knee flexion contracture that would render a BKA non-functional. For level selection I aim for about 12-15cm of tibia below the tibial tuberosity - a hand's breadth - giving a good lever arm with adequate soft-tissue cover, while avoiding a stump shorter than about 8cm which fits poorly and is prone to contracture, or an over-long distal stump where perfusion and padding are worse. If perfusion data and the clinical picture suggest the BKA will not heal, I would choose an AKA rather than risk a failed BKA that has to be revised, because a non-healing BKA converted to AKA is a worse outcome than a primary AKA.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"Describe the long posterior flap (Burgess) technique for a below-knee amputation. How does it differ from the skew flap, and what does the evidence say about which to use?"

PRACTICAL APPROACH
I would position the patient supine and mark my level about 12-15cm below the tibial tuberosity. For the Burgess technique I make the anterior skin incision at the level of bone section and fashion a long posterior myocutaneous flap, with its length approximately equal to the antero-posterior diameter of the leg at that level plus a small margin, so it folds anteriorly without tension. I divide the anterior and lateral compartment muscles, doubly ligate the anterior tibial vessels, and perform traction neurectomies of the deep and superficial peroneal nerves. I divide the tibia at the chosen level with a 45-60 degree anterior bevel and smooth all edges, and divide the fibula 1-2cm shorter with a bevel so it does not become a prominence. I then raise the posterior flap of skin, fascia, soleus and gastrocnemius, individually doubly ligating the posterior tibial and peroneal vessels, and performing a traction neurectomy of the tibial nerve - importantly ligating the artery that accompanies the tibial nerve to prevent a stump haematoma. The sural nerve in the flap is treated likewise. I tailor and debulk the soleus, then bring the gastrocnemius anteriorly and perform a myoplasty over the bevelled bone end to create a padded stump, placing a drain and closing so the scar lies anteriorly off the weight-bearing bone-end. The skew flap, described by Kingsley Robinson, instead uses two equal-length sagittal skin flaps rotated about 25 degrees so the apices lie antero-medially and postero-laterally, based on the cutaneous perforator/angiosomal supply, with a gastrocnemius myoplasty still padding the bone end; the aim is a more cylindrical stump with the scar away from bone. In terms of evidence, the long posterior flap has a robust gastrocnemius-based blood supply and is the traditional workhorse for dysvascular limbs, while the multicentre randomised trial by Ruckley comparing skew flap with long posterior flap found no significant difference in primary stump healing. So both are valid - I choose based on familiarity, the perfusion pattern of the limb and the soft-tissue available.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"What are the main complications of a below-knee amputation and how do you prevent them? A diabetic patient's stump becomes tense and increasingly painful 12 hours after surgery with ooze through the dressing - what has happened and what do you do?"

PRACTICAL APPROACH
The complication that dominates the dysvascular BKA is wound failure with flap necrosis and dehiscence, which can force conversion to a higher level. I minimise this by selecting the level on perfusion data such as TcPO2 and ABI, handling the flaps atraumatically, closing without tension, excising any dubious margin, and optimising glycaemia and nutrition. Other early complications are stump haematoma, infection, and later symptomatic neuroma, phantom and residual limb pain, and knee flexion contracture. Haematoma is prevented by individually ligating each vascular pedicle and the artery accompanying the tibial nerve, releasing the tourniquet to re-check haemostasis and using a drain. Infection risk - high in this population - is reduced by controlling sepsis before definitive closure, prophylactic antibiotics and adequate debridement, with a staged guillotine amputation first if grossly infected. Neuroma and phantom pain are reduced by clean traction neurectomies that let the nerve retract into muscle away from the scar, and by multimodal pre-emptive analgesia. Knee flexion contracture is prevented by a rigid dressing in extension, avoiding a pillow under the knee, and early physiotherapy. For this patient, a stump that is tense, increasingly painful and oozing 12 hours postoperatively is a stump haematoma until proven otherwise - most likely from a slipped ligature on a major pedicle, or an unligated artery accompanying the tibial nerve. I would assess the patient clinically (pain, swelling, dressing soakage), check observations and haemoglobin for ongoing bleeding, and recognise that an expanding haematoma directly threatens the perfusion and healing of the flap. My management depends on the size and trajectory. A small, stable haematoma can be managed expectantly with a compressive rigid dressing and close observation. However, a tense, expanding haematoma with a falling haemoglobin warrants a return to theatre for evacuation, washout and meticulous haemostasis - re-ligating the offending pedicle - to decompress and protect the flap. I would correct any coagulopathy and review antiplatelet/anticoagulant medication, and ensure the stump is then supported in a rigid dressing.

Below-Knee (Transtibial) Amputation - Exam Summary

Clinical summary

Key Evidence

Landmark and Outcome Evidence

Long posterior myocutaneous flap for the dysvascular leg (Burgess)

Level IV
Burgess EM, Romano RL, Zettl JH, Schrock RD Jr • J Bone Joint Surg Am (1971)
Clinical Implication: Defines the workhorse flap still used for the dysvascular transtibial amputation worldwide; the posterior-flap blood supply underpins its reliability in critical ischaemia.
Verify on PubMed (PMID 4934074)

Skew-flap myoplastic below-knee amputation (Robinson)

Level IV
Robinson KP, Hoile R, Coddington T • Br J Surg (1982)
Clinical Implication: Provides an alternative to the long posterior flap that yields a well-shaped, perforator-perfused stump, particularly where a cylindrical residuum aids socket fit.
Verify on PubMed (PMID 7104656)

Skew flap versus long posterior flap: multicentre randomised trial (Ruckley)

Level I
Ruckley CV, Stonebridge PA, Prescott RJ • J Vasc Surg (1991)
Clinical Implication: Both flap designs heal and rehabilitate comparably; flap choice should rest on surgeon familiarity, limb perfusion pattern and available soft tissue rather than a presumed superiority.
Verify on PubMed (PMID 1999863)

Pneumatic tourniquet in trans-tibial amputation for vascular disease (Wolthuis)

Level II
Wolthuis AM, Whitehead E, Ridler BMF, Cowan AR, Campbell WB, Thompson JF • Eur J Vasc Endovasc Surg (2006)
Clinical Implication: Challenges the dogma that a tourniquet is contraindicated in dysvascular amputation, but as a non-randomised cohort it is suggestive rather than definitive; many surgeons still omit it in critical ischaemia.
Verify on PubMed (PMID 16427337)

Energy cost of prosthetic walking by amputation level (Waters)

Level II
Waters RL, Perry J, Antonelli D, Hislop H • J Bone Joint Surg Am (1976)
Clinical Implication: Provides the objective basis for preserving the knee whenever the limb will heal: a transtibial level demands far less energy and yields better function than transfemoral amputation.
Verify on PubMed (PMID 1249111)

References

  1. Burgess EM, Romano RL, Zettl JH, Schrock RD Jr. Amputations of the leg for peripheral vascular insufficiency. J Bone Joint Surg Am. 1971;53(5):874-890. Classic description of the long posterior flap transtibial amputation with myoplasty in dysvascular limbs.

  2. Burgess EM. Amputations below the knee. Artif Limbs. 1969;13(1):1-12. Foundational account of below-knee amputation principles and stump management.

  3. Romano RL, Burgess EM. Level selection in lower extremity amputations. Clin Orthop Relat Res. 1971;74:177-184. Principles of choosing the amputation level to balance healing and prosthetic function.

  4. Robinson KP, Hoile R, Coddington T. Skew flap myoplastic below-knee amputation: a preliminary report. Br J Surg. 1982;69(9):554-557. Original description of the skew-flap technique based on cutaneous perforator supply.

  5. Robinson KP. Skew-flap below-knee amputation. Ann R Coll Surg Engl. 1991;73(3):155-157. Refinement and rationale of the skew-flap design for a cylindrical, well-perfused stump.

  6. Ruckley CV, Stonebridge PA, Prescott RJ. Skewflap versus long posterior flap in below-knee amputations: multicenter trial. J Vasc Surg. 1991;13(3):423-427. Multicentre RCT showing no significant difference in primary stump healing between the two flaps.

  7. Wolthuis AM, Whitehead E, Ridler BM, Cowan AR, Campbell WB, Thompson JF. Use of a pneumatic tourniquet improves outcome following trans-tibial amputation. Eur J Vasc Endovasc Surg. 2006;31(6):642-645. RCT demonstrating reduced blood loss and transfusion with tourniquet, without increased wound failure.

  8. Burgess EM, Romano RL. The management of lower extremity amputees using immediate postsurgical prostheses. Clin Orthop Relat Res. 1968;57:137-146. Introduction of the rigid dressing and immediate postsurgical prosthetic fitting concept.

  9. Holloway GA Jr, Burgess EM. Cutaneous blood flow and its relation to healing of below knee amputation. Surg Gynecol Obstet. 1978;146(5):750-756. Early evidence linking skin perfusion to transtibial wound healing and level selection.

  10. Brookes JDL, Jaya JS, Tran H, et al. Broad-Ranging Nutritional Deficiencies Predict Amputation in Diabetic Foot Ulcers. Int J Low Extrem Wounds. 2020;19(1):27-33. Demonstrates nutritional status (including albumin) as a predictor of amputation and healing.

  11. Waters RL, Perry J, Antonelli D, Hislop H. Energy cost of walking of amputees: the influence of level of amputation. J Bone Joint Surg Am. 1976;58(1):42-46. Demonstrates that prosthetic walking performance and oxygen cost are progressively better the lower (more distal) the amputation level.

  12. Ameli FM, Byrne P, Provan JL. Selection of amputation level and prediction of healing using transcutaneous tissue oxygen tension (PtcO2). J Cardiovasc Surg (Torino). 1989;30(2):220-224. Prospective study supporting transcutaneous oxygen tension as a valid predictor of primary amputation healing.