Objective To assess the clinical effect of microsurgicaltreatment for bone defect of the first carpometacarpal joint. Methods From February 2001 to August 2004, the pedicled free graft of second tarsometatarsal joint was transplanted to repair bone defect of the first carpometacarpal joint according to the shape and area of tissue defect of hand in 3 patients. The dosalis pedis flap was simultaneously used to repair soft tissue defect of carpometacarpe and the big thenar in 2 cases. The donor site was sutured directly or covered byintermediate thickness skin flap. Results The vessel of the bone flaphad constant anatomical location，the operation procedure was easy. Moreover it had minimal effect ondonor, the flap of dosalis pedis could be used to repair soft tissue defect in this area. Three cases were followed up 1 to 2 years.The shape of the reconstituted thumb was normal. The healing time of clinical fracture of the first carpometacarpal joint was 2 to 3 months. The function recovery of the reconstituted thumb was satisfactory. Conclusion It is an effective method to repair bonedefect of the first carpometacarpal joint with the pedicled second tarsometatarsal joint graft.