Treatment for Congenital Synostosis of the Fourth and Fifth Metacarpals with the Hemicallotasis Technique

: Simultaneous reconstruction of a traumatic defect of the trapeziometacarpal joint and the first metacarpal with a composite dorsalis pedis flap is described. The transplant, consisting of the second metatarsal and the second metatarsophalangeal joint, was reversed at the defect site for the metatarsophalangeal joint to become a new trapeziometacarpal joint. A long vascular pedicle was necessary for direct micro-vascular anastomoses to the radial vessels at the wrist. This transfer can be expected to be effective in reconstructing composite hand defects involving the trapeziometacarpal joint and the entire first metacarpal bone.