Free Vascularised Fibula Transfer

Dead scaffold versus living bone. A non-vascularised cortical graft is dead scaffold. It incorporates by creeping substitution, weakens transiently at 6 to 18 months, and fails unpredictably in defects greater than 6 cm, in infected beds and in irradiated tissue. The vascularised fibula arrives with its own blood supply: its osteocytes survive on the peroneal pedicle, there is no creeping-substitution phase of weakness, and the graft heals to host bone like a two-level fracture.

What living bone can do. The other properties follow from the blood supply:

• Hostile beds — it carries its own blood supply into irradiated, scarred or previously infected fields, and delivers antibiotics and immune cells
• Adaptation — it hypertrophies under cyclical load over 1 to 2 years, eventually approaching host-bone diameter in the tibia and forearm
• Growth — proximal fibular epiphyseal transfer, on the anterior tibial artery, can reconstruct a growing physis (for example the proximal humerus in children)
• Geometry — straight tubular cortical bone up to about 26 cm, an ideal cross-section for the radius, ulna and humerus, and double-barrelled for the tibia and femur

Two branch points. The defect is measured after radical excision to healthy bleeding bone, and the bed is characterised as clean or hostile: chronic infection, prior irradiation, scarred soft tissues or failed grafting. Length and hostility then decide the reconstruction. A short defect in a clean bed is reliably bridged by a non-vascularised graft; a longer one is not, and the choice moves to a vascularised fibula or bone transport; a hostile bed shifts the choice to vascularised bone at any length, because it will not heal an avascular graft.

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The upper limb. The forearm and humerus suit a lone fibula because its diameter closely matches the radius and ulna. After resection of a distal radius giant cell tumour the wrist can be arthrodesed with the graft, or the proximal fibula used to recreate the radiocarpal surface.

Smoking and the vessels. Heavy smoking is a relative contraindication because it threatens flap thrombosis and non-union, and severe peripheral vascular disease is weighed the same way.

The bone. About 26 cm of the adult fibula is usable once the two ends are spared: at least 6 cm is retained distally above the lateral malleolus for the stability of the ankle mortise, and the head and neck are left proximally to protect the common peroneal nerve, which winds around the neck under the origin of peroneus longus. The proximal osteotomy sits at least 6 cm distal to the head. The head is taken only when the proximal epiphysis is deliberately transferred for a growing reconstruction, and then it travels on the anterior tibial vessels, not the peroneal.

The pedicle. The graft travels on the peroneal (fibular) artery, 1.5 to 2.5 mm in calibre, with its paired venae comitantes. It lies in the deep posterior compartment between tibialis posterior and flexor hallucis longus, with the posterior tibial neurovascular bundle medial to it, and is dissected proximally to the tibioperoneal trunk for maximal length and calibre, which gives a pedicle of 4 to 8 cm.

Two blood supplies to the bone. The nutrient artery enters the posteromedial cortex of the middle third, posterior to the interosseous membrane, and supplies the endosteal inner two-thirds of the cortex. A segment that excludes the middle third relies on periosteal supply alone, which is why the middle third must be included in the graft. Segmental periosteal and musculoperiosteal branches from the peroneal artery run along the whole length of the bone and supply the outer cortex; a 1 to 2 mm cuff of tibialis posterior and periosteum left on the medial fibula protects them and the nutrient vessel.

Why the segmental supply matters. It is what makes a closing-wedge osteotomy safe. Provided the periosteal sleeve and the pedicle are preserved, both limbs of a double-barrel construct and each segment of a contoured graft remain perfused, even where a segment lacks the nutrient artery.

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The skin paddle. Septocutaneous perforators in the posterior crural septum, at the junction of the middle and distal thirds, carry a skin paddle with the bone. It is the monitoring window for a flap that is otherwise buried.

The distal remnant in children. Retaining 6 cm is not enough in the skeletally immature: proximal migration of the remnant still produces progressive ankle valgus, so a distal tibiofibular synostosis (Langenskiöld) or a transfixion screw is added at harvest.

Peronea arteria magna. In roughly 0.2 to 5 percent of limbs, the Type III variant, the peroneal artery is the dominant or sole supply to the foot, with absent or hypoplastic anterior and posterior tibial arteries. Harvesting the pedicle devascularises the foot, so the variant is an absolute contraindication and every donor leg is screened for it.

History and examination. Ask about donor leg trauma or surgery, claudication and smoking. Palpate the dorsalis pedis and posterior tibial pulses and put a handheld Doppler on all three crural vessels.

Imaging the donor leg. Angiography is selective rather than routine. CT or MR angiography, or catheter angiography, is obtained when the pulses are abnormal, after previous trauma or with vascular disease, and it is mandatory in congenital limb anomalies.

Imaging the recipient site. Full-length radiographs, CT for the defect geometry and MRI for tumour margins. Measure the defect and add 2 to 3 cm for intramedullary docking or step-cuts, so that the resection margins and the graft length are planned together before harvest.

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Recipient vessels. Plan the artery, end-to-side to a major axial vessel or end-to-end to a branch, and two venous options. In irradiated necks or limbs consider preoperative angiography of the recipient bed.

Team and logistics. A two-team approach, with resection and recipient preparation running at the same time as the harvest, shortens the ischaemia time. Microscope, microinstruments, couplers and an implantable Doppler are available.

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Consent. The conversation covers:

• Flap failure, roughly 5 percent in experienced hands, and re-exploration
• Stress fracture of the graft
• Donor morbidity: great-toe clawing, ankle discomfort, weakness and sensory change
• Prolonged protected weight-bearing

Union. The fibula-host junctions heal like fractures, by callus, not by creeping substitution, and union is typically at 3 to 6 months in a favourable bed. Until then the construct is protected fully, because the fibula alone carries only a fraction of femoral or tibial load.

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The stress-fracture window. Loading drives periosteal apposition, but the months between 3 and 12 are the period of peak stress-fracture risk: roughly 10 to 25 percent of lower-limb reconstructions, highest where a single-barrel fibula reconstructs the femur or tibia without allograft or intramedullary nail protection. In de Boer and Wood's 62 grafts, fractures occurred in 25 percent, at an average of eight months: the fatigue window is the first year, not the first weeks.

If it fractures. Most unite with immobilisation and protected loading, because the bone is vascularised and retains its intrinsic healing capacity. Persistent instability warrants supplementary fixation with bone graft.

Hypertrophy and the fixation paradox. Over 1 to 2 years the cortex thickens and the diameter increases toward host dimensions, greater and faster in children and in weight-bearing bones; progressive hypertrophy is the living graft's response to load. The trap is to treat protection as a steady state. de Boer and Wood found hypertrophy was enhanced precisely where the graft was not bypassed by internal fixation, so a rigid construct that carries the load indefinitely prevents the remodelling that would eventually make the graft safe.

The staged plan. Protection and hypertrophy pull in opposite directions, so the plan is staged: shield the graft through the fatigue window of the first year, then deliberately transfer load to it by graduated weight-bearing and, where appropriate, dynamisation or hardware removal. Graft length and the use of additional bone graft made no difference to either stress fracture or hypertrophy in de Boer's series. For large-diameter bones the durable answer is more bone, not more metal: double-barrel or Capanna constructs, with spanning fixation retained until hypertrophy and loading graduated.

Related pages. The alternatives this operation is chosen against: Bone Transport Techniques and Masquelet Induced Membrane Technique both avoid a microvascular anastomosis, and Allograft-Prosthetic Composite Reconstruction is the alternative when the defect involves a joint. Nonunion Management frames the whole decision.

• Global epidemiology of use — FVFG is practised worldwide wherever microsurgical expertise exists; the dominant indications differ by region: oncologic intercalary reconstruction and congenital pseudarthrosis in high-income centres; post-traumatic and post-infective defects dominate in many lower-resource settings, where bone transport is often preferred because it needs no microsurgical infrastructure.
• Society guidance — no society issues an FVFG-specific guideline. Relevant framework documents: BOA/BAPRAS BOAST on open fractures (early combined orthoplastic decision-making for segmental bone loss, reconstruction within a definitive soft-tissue plan); AO principles for segmental defect management (defect classification, staged strategies including Masquelet, transport and vascularised graft); musculoskeletal tumour society consensus favours biological reconstruction (allograft, FVFG, Capanna) for intercalary defects in the young where expertise allows.
• Registries — no implant-style registry captures FVFG; evidence rests on institutional series and systematic reviews, which consistently report union above 80 to 90 percent after all secondary procedures, with reoperation common (junctional grafting, stress-fracture management).
• Resource-setting variation — where microsurgery is unavailable: bone transport, Masquelet, ipsilateral pedicled fibula transfer for tibial defects (Huntington procedure — no microsurgery needed), or non-vascularised fibula strut for smaller defects. Selective rather than routine angiography is now the majority international practice for donor-limb assessment.

• Routine versus selective donor angiography — routine imaging detects rare variants but adds cost and (for catheter studies) risk; most units now image selectively on clinical/Doppler criteria, with a lower threshold in congenital deformity.
• FVFG for femoral head osteonecrosis — Urbaniak's results are difficult to reproduce; the operation is long, donor morbidity real, and modern arthroplasty in the young performs well. Many centres have abandoned it; others reserve it for pre-collapse disease in patients under 40.
• FVFG versus Ilizarov transport for tibial defects — comparable union in experienced hands; transport avoids microsurgery and donor morbidity but demands months in frame; choice is driven by defect length, soft tissues, patient tolerance and local expertise.
• Capanna versus fibula alone versus allograft alone — the hybrid adds operative complexity; whether it is required for defects under about 10 cm in the upper limb (where fibula alone performs well) is debated.
• Osteocutaneous paddle versus buried flap with implantable Doppler — paddle gives the most reliable monitoring but adds donor scarring and occasionally skin-graft morbidity.