Free flaps based on the anterior interosseous artery.

Free flaps based upon the anterior interosseous artery were defined anatomically by 15 dissections. The anterior interosseous artery runs distally for the entire length of the anterior interosseous nerve on the palmar surface of the interosseous membrane. A dorsal branch of the anterior interosseous artery penetrates the interosseous membrane about 5 cm proximal to the distal radioulnar joint and gives off a tributary radially. This tributary ascends the ulnar aspect of the radius to provide blood to the radius and the dorsal wrist skin. Based on these anatomical findings, four types of free flaps were possible: fasciocutaneous, osteocutaneous, neurovascular flaps, and one muscle flap. All seven dorsal wrist flaps successfully covered the defects. Three of four nerve flaps demonstrated patency of the arterial pedicle with digital Allen's test and good sensory recovery of the reconstructed area. One reconstruction of Blauth type II hypoplastic thumb using an ipsilateral pronator quadratus free-muscle flap provided a functionally and cosmetically satisfactory result.