Background The use of a free,vascularized fibular graft is an important technique for the reconstruction of large defects in long bones.The technique has many advantages in strong,tubular bones; a more reliable vascular anatomy with a large vascular diameter and long pedicle is used,minimizing donor-site morbidity.Due to limitations in both fibular anatomy and mechanics,they cannot effectively be used to treat large limb bone defects due to their volume and strength.Methods From 1990 to 2001,16 clinical cases of large bone defects were treated using vascularized double-barrel fibular grafts.Patients were evaluated for an average of 10 months after surgery.Results All the patients achieved bony union; the average bone union took 10 months post surgery,and no stress fractures occurred.Compared with single fibular grafts,the vascularized double-barrel fibular grafts greatly facilitate bony union and are associated with fewer complications,suggesting that the vascularized double-barrel fibular graft is a valuable procedure for the correction of large bone defects in large,long bones in addition to enhancing bone intensity.Conclusions The vascularized double-barrel fibular graft is superior to the single fibular graft in stimulating osteogenous activity and biological mechanics for the correction of very large bone defects in large,long bones.Free vascularized folded double-barrel fibular grafts can not only fill up large bone defects,but also improve the intensity margin.Therefore,this study also widens its application and enlarges the treatment targets.However,in the case of bone deformability,special attention should be paid to bone fixation and protection of donor and recipient sites.