The fibular free flap is the most widely used flap for jaw reconstruction. Flap contouring requires removal of bone excess in the proximal segment by a subperiosteal dissection, preserving vascular connections between the pedicle and the bone and leaving well vascularized periosteum attached to the vascular pedicle. Among about 100 reconstructions with fibular flaps, 4 cases were observed of abnormal ossification along the vascular pedicle. Periosteum preserves its osteogenic capability after transposition, especially in a revascularized flap; this characteristic, together with the direct contact with the bone, allows the possibility of new bone formation along the pedicle. It would appear necessary to change the technique of reducing fibular excess, with removal of periosteum together with the bone, in order to avoid the complication described.