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Page 2 of 18 Stoneburner et al. Plast Aesthet Res 2020;7:13 I http://dx.doi.org/10.20517/2347-9264.2019.028

Keywords: Soft tissue coverage, free flaps, rotational flaps, microsurgery, bone osteogenesis, bone transport, lower
extremity reconstruction, limb salvage

INTRODUCTION
High-energy lower extremity trauma with massive bone and soft tissue loss poses a challenge for
orthopedic and reconstructive surgeons. Higher Gustilo-Anderson fracture type, Orthopaedic Trauma
Association Open Fracture classification, and limb salvage index score are associated with a poor prognosis,
[1-3]
including high risk of infection, nonunion, and amputation . With improvements in surgical techniques
and protocol-driven traumatic lower extremity management at tertiary care centers, limb salvage rates have
[4-6]
significantly increased, reaching up to 90% in some reports .

Early aggressive radical debridement, skeletal stabilization and soft tissue coverage is the critical first step
[7]
in lower extremity salvage . Depending on the extent of trauma and the size and nature of the defect, there
are many reconstructive options available to the orthopedic and plastic surgeon. When the bony injury is
“critical sized” - that is, too large to heal without additional intervention - additional steps must be taken to
achieve bony union.

The choice of reconstructive technique is often determined by size. The induced membrane technique is
a viable option for small and large defects, although results may differ based on anatomic location. Larger
[7-9]
defects may require vascularized transfer from the fibula or iliac crest . Some patients may be poor
candidates for vascularized bone graft, the defect may exceed the size of the available graft or there may
be concerns about size mismatch between vascularized bone and the defect location. In these cases, bone
transport using distraction osteogenesis can be utilized. Bone transport in combination with free soft tissue
transfer is an effective treatment for nonunions, segmental defects, and osteomyelitis.

This systematic review summarizes and discusses reconstructive options available for traumatic extremity
injuries when bony transport and free tissue transfer are required for limb salvage. A series of case
examples in combination with the senior authors’ surgical techniques at a single academic institution is
described.

Bone deficit treatment options
Critical bone loss is devastating for patients; orthopedic and plastic surgeons must be prepared to treat
these patients with a multidisciplinary approach. It most commonly occurs in patients following trauma,
infection, and oncologic resection. Critical bony defects, by definition, necessitate additional intervention,
as the defect is too large to undergo the normal physiologic healing process. The inability for bone to
spontaneously regenerate is often largely controlled by the presence or absence of periosteal blood supply,
as well as a viable docking site for reduction . Defects greater than 2.5 cm are usually considered critical,
[10]
although there is poor evidence and thus some disagreement between experts with this definition [11-13] .
In these situations, primary bone grafting is also insufficient to obtain union. More advanced treatment
options include the induced membrane technique and bone transport through distraction osteogenesis.

Induced membrane techniques
The induced membrane technique, often eponymously referred to as the Masquelet technique, is a two-
stage technique involving placement of a foreign body within the defect that results in a biologically-
active membrane around the defect, which can then provide biology for subsequent bone formation using
graft [14,15] . The first stage entails radical debridement and skeletal stabilization [15,16] . A spacer, typically made
from polymethylmethacrylate cement, is placed. A pseudomembrane will form around the spacer. This
spacer is biologically active and contains growth factors involved in fracture healing and angiogenesis. In