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Evans et al. Plast Aesthet Res 2022;9:34 https://dx.doi.org/10.20517/2347-9264.2021.134 Page 5 of 14

Distraction osteogenesis has proven to be a reliable method for repairing segmental bony defects measuring
[75]
up to 10 cm . In the Ilizarov technique, first described in the 1950s, distraction is achieved via placing an
[77]
external fixation device with carefully planned corticotomies to preserve blood supply . Following an
initial latency phase of 3-10 days, gradual distraction of the proximal and distal segments is achieved at an
average gain in length of 1cm every 30 days. Upon completion of distraction, the newly formed bone within
the distraction gap is allowed to bridge and corticalize via a consolidation phase. Numerous frames and
external fixation devices have since been described to improve techniques in distraction osteogenesis. The
Taylor spatial frame is a modern modification to the traditional Ilizarov technique, in which a multiplanar
external hexapod frame is used to improve versatility in correcting rotation, angulation and translation of
bony deformities [75,78] .

Autologous nonvascularized bone grafting is largely considered the gold standard in repairing small bony
defects of the lower extremity. Cancellous bone can be accessibly harvested from iliac crest, femur, or tibia,
[75]
and grafted into the defect for repair . Additionally, smaller corticocancellous bone flaps, such as the
medial femoral condyle flap, have also demonstrated efficacy in repairing small defects in post-traumatic
non-unions [79-82] [Figure 1]. In the reconstruction of large bony defects, significant structural and weight-
bearing support is needed for functional limb salvage [75,83] . Historically, these defects were reconstructed with
large cadaveric allografts, as vascularized bone flaps were associated with prolonged immobilization and
early fracture. While allograft reconstruction has proven successful in limb salvage, it is associated with a
higher incidence of infection and non-union when compared to vascularized bone grafts [75,84-88] . The first
vascularized bone grafting was described in 1905 when a pedicled fibular graft was utilized to fill a large
tibial defect . In 1975, the first microsurgical vascularized bone graft was performed, using a fibula to fill a
[85]
[88]
large tibial defect in the contralateral leg . While the fibula remains one of the most commonly used
vascularized bone flaps for repairing large bony defects, multiple adaptations have contributed to its success
in lower extremity reconstruction. One of these adaptations is the Capanna Technique, which was first
described in 1993. The Capanna technique combines the advantages of allograft structural support and
vascularized bone graft osteogenesis. In this technique, the free fibula acts as an intramedullary rod within
an allograft conduit, and is used to reconstruct large boney defects to provide early structural integrity and
decreased rates of non-union and infection [75,83,89,90] .

In addition to reconstruction with bone grafting, several autologous and allograft products are available to
help augment fracture healing . Platelet-rich plasma, bone marrow mesenchymal stem cells, and adipose-
[75]
derived stem cells, are examples of autologous therapies that can be used to promote wound healing in areas
of traumatic injury. These therapies work similarly to polarize M2 macrophages and upregulate key growth
factors such as transforming growth factor β (TGFβ), vascular endothelial growth factor, and fibroblast
growth factor within the wound bed . The newly polarized M2 macrophages and increased levels of
[91]
growth factors work synergistically to augment wound healing by reducing inflammation, inducing collagen
synthesis, and promoting angiogenesis. Similar to autologous options, allograft material such as bone
morphogenic protein (BMP), demineralized bone matrix, and ViviGen are additional adjuvant therapies
that can be used to promote fracture healing. BMP contains functional growth factors to promote bone
regeneration via osteoinduction, whereas demineralized bone matrix acts as a scaffold to promote bone
[90]
formation via osteoconduction . Vivigen is a unique cellular allograft made up of three components to
promote bone formation: Lineage committed bone cells to induce osteogenesis, a natural bone scaffolding
to promote osteoconduction, and growth factors to promote osteoinduction. Overall, advancements in
these adjuvant therapies may help further decrease complication and non-union rates following lower
extremity trauma fixation.