Selecting a free flap for soft tissue coverage in lower extremity reconstruction

Background: Goals of lower extremity microvascular reconstruction (LEMR) include the restoration of function, prevention of infection, and optimal cosmesis. Indications for LEMR include large defects that are not amenable to pedicled options, a large zone of injury, and large complex defects. The novice microsurgeon should first master a handful of free flaps to develop an armamentarium of options for addressing such defects. The scope of this review is to provide free flap options for LEMR in any of the thirds of the lower leg. After reading this article, the reader will understand variations, advantages, disadvantages, indications, and tips for raising each of these flaps. Methods: Six most commonly used free flaps for LEMR are described in this paper, including the anterolateral thigh flap (ALT) and its variations, the radial forearm flap (RFFF), the lateral arm flap (LAF), the gracilis muscle flap, the rectus abdominis flap (RAF) and the latissimus dorsi flap and its variations. Indications, advantages, disadvantages and technique tips are discussed for each flap. Moreover, selection of the recipient vessels, preoperative management along with an algorithm are also provided. Conclusions: The ALT flap is a workhorse in covering defects of the leg, foot, and ankle. It's the flap of choice at our institution, especially given the number of traumatic wounds seen as a result of motor vehicles, all-terrain vehicles (ATV), lawnmowers, and gunshot wounds (GSW). At times, the lower extremity zone of injury requires a distant donor site. The RAF can also provide coverage for large soft tissue defects but donor-site morbidity remains its main drawback. The LAF and RFFF provide two pliable options, one that provides pliable soft tissue with minimal donor site morbidity and another that provides a long pedicle. The free gracilis flap is an excellent choice for crossing the ankle joint. Lastly, the free latissimus dorsi is indicated for large defects of the lower extremity independently of the location.