The choice of flap is dictated by tissue requirements in the limb. Composite flaps of skin, muscle or fascia and bone are often used. Recipient vessels in the injured extremity, roughly approximating the flap vessels in size, are prepared under the microscope for microvascular anastomosis. After isolating the flap, the donor vessels are divided and the tissue transplanted to the extremity. Because these vessels are often less than 1mm in diameter, and since the only blood supply is through these anastomoses, thrombosis will lead to flap death.
Technique is critical.
The indications and contraindications for free tissue transfer are listed in Table 3. Gustilo IIIc injury of the ankle following treatment of his fracture. A composite free flap of skin fascia and tendon is harvested from the forearm and isolated on the radial artery and cephalic vein. Figure 7C. Following free tissue transfer to the ankle. The palmaris longus tendon was used to replace the missing posterior tibialis tendon and the radial artery has been anastomosed to the severed posterior tibial artery.