The Free Fibula Osseous/Osseocutaneous Flap

The free fibula flap is a workhorse flap for osseous free tissue transfer in extremity reconstruction. It is also the flap of choice for mandibular defects, but this is beyond the scope of this book. The fibula has several advantages that makes it an ideal choice when long bone defects reconstruction via osteogenesis is required: It is a long bone that can provide up to 25–30 cm of length when harvested; it is mainly comprised of cortical bone, making it ideal for rigid fixation; it is a straight bone that is triangular in cross section, providing adequate support after reconstruction; it can be shaped to fit the defect via multiple osteotomies without compromising its blood supply due to its segmental vascularization; once the anatomy is understood, the dissection is relatively fast and easy to perform; there is minimal donor site morbidity and finally the vascular pedicle is long and the diameter of the peroneal artery and veins are large making the anastomosis less challenging. An in-depth understanding of the anatomy of the lower leg, including the contents of all four compartments is of paramount importance to perform a safe dissection. The proximal and distal ends of the fibula need to be left in situ, to avoid destabilization of the leg. This is especially important in children, where destabilization can lead to a valgus deformity of the ankle. During dissection, care needs to be taken to identify the common peroneal nerve as it courses around the neck of the fibula. Inadvertent injury can result in loss of function of the muscles of the anterior compartment of the leg (foot drop) and loss of sensation along the course of the superficial peroneal nerve. The flexor hallucis longus (FHL) muscle is the most vulnerable muscle during dissection, and loss of its function may result from the harvest. Additionally, fibrosis of the tendon can lead to permanent flexion deformity of the great toe.The free fibula flap can be harvested as an osseous or osseoseptocutaneous flap with a skin paddle in the lateral aspect of the flap based off septocutaneous peroneal perforators. While sacrifice of the peroneal vessels usually does not result in distal foot ischemia, a preoperative angiogram may be of value in patients with significant peripheral arterial disease.