Anatomical bases of the second toe composite dorsal flap for simultaneous skin defect coverage and tendinous reconstruction of the dorsal aspect of the fingers.

Coverage of the dorsal aspect of the fingers is difficult, especially when the soft tissue defect is large and involves extensor apparatus and joints. Tendinous and/or articular reconstruction is not usually performed simultaneously with cutaneous repair. The aims of this study were: (1) to accurately determine the precise position of the first common dorsal metatarsal artery (FDMA) on the dorsal aspect of the foot, and (2) to enumerate the anatomical structures which could be harvested 'en-bloc' in order to design composite flaps. The precise position of the FDMA was studied from 22 anatomical specimens after selective injection of the arterial network. Its cutaneous area measured 75 x 40 mm on average. The extensor apparatus of the second toe was supplied by the FDMA and its lateral branch to the second toe by 2.7 branches on average over a length of approximately 75 mm. The medial dorsal digital artery was generally the main source of blood supply to the proximal interphalangeal joint (PIP), capsule, ligaments, head of proximal phalanx and base of middle phalanx. It is then possible to design composite flaps including both skin and extensor apparatus, and total or partial PIP joint, if necessary, based on the FDMA and the medial dorsal digital artery, without prejudice to the second toe. The average length of the arterial pedicle (60 mm) makes its suture to the dorsal metacarpal artery, the dorsal carpal branch or the radial artery easy. The harvesting technique for such a flap is described for each anatomical type of FDMA; it has to be adapted to both the type and extent of the defect. Its use is in accordance with the modern classical principle of 'all in one stage with early mobilisation', thanks to adequate coverage whose blood supply does not depend on local vascularisation, and which brings its own physiological vascular supply.