The functional peroneus brevis as a third muscle component in the osteomyocutaneous fibula free-flap system

Up to now, the peroneus brevis muscle was harvested as a non-functional pedicled muscle flap for defects around the ankle and the anterior lower leg. It has a reliable dual segmental vascularisation from the peroneal and the anterior tibial artery and a long, single motor nerve entering proximally. We report of a free microvascular transfer of the peroneus brevis as a neurotised functional muscle component in a composite osteo-musculo-cutaneous flow-through fibula flap. The flap components were used to reconstruct extensive radial and soft-tissue defects in a severely damaged forearm, whereas the peroneus brevis nerve was coapted to the proper flexor carpi radialis (FCR) motor nerve to counterbalance ulnar abduction, as all radial abductors were lost in the injury. Thirteen months later, the arm was fully reconstructed and an active radial abduction of 15° by the contracting peroneus muscle was achieved. Donor-site complications were absent. The peroneus brevis can expand the versatility of the peroneal-vessel-flap system as a third muscular component in four possible ways: a) addition of plain muscle bulk in the middle- and lower third of the fibula if left attached to the bone, b) as a reinnervated functional muscle as presented here, c) as a distally based muscle component if released from its origin from the middle third of the fibula and pedicled on its distal segmental branches from the peroneal vessels or d) as a distally pedicled osteomuscular flap permitting individual placement of a middle fibula segment.