BACKGROUND: Bone lengthening and free vascularized fibula graft (FVFG) represent two prevalent modalities for bone defect repair. The objective of this study was to compare the efficacy disparities between FVFG and single - segmental bone lengthening (BL) when the Orthofix external fixator was utilized in the treatment process. METHODS: The follow - up data of 72 patients with femoral defects, who received treatment from January 2009 to May 2019, were collected for retrospective analysis. Among them, 60 comparable patients were stratified into two groups: one group of 30 patients received free vascularized fibular graft in combination with Orthofix external fixation (FVFG group), and the other group of 30 patients underwent single - segmental bone lengthening using the Orthofix external fixator (BL group). The specific aspects evaluated encompassed operation time, intraoperative blood loss, postoperative Activities of Daily Living (ADL) score, assessment by the Association for the Study and Application of the Method of Ilizarov (ASAMI), limb length discrepancy (LLD), external fixation index, bone union status, and complications. RESULTS: 1.Surgical - related indicators: The mean operation time in the FVFG group ( 5.04 ± 1.22 h) was significantly longer than that in the BL group (1.58 ± 0.56 h, p<
0.001). The intraoperative blood loss (450 ± 190.73 ml) in the FVFG group was substantially higher than that in the BL group (120 ± 46.23 ml, p<
0.01). Although the duration of external fixator use in the FVFG group (16.9 ± 3.52 months) was marginally longer than that in the BL group (15.53 ± 2.09 months), this difference did not reach statistical significance (p=0.073). 2.Postoperative complications: According to the Paley classification system, no significant differences were observed between the two groups in terms of nail infection, nail loosening, limb edema, nonunion (including nonunion in the BL group and fibula nonunion in the FVFG group), and postoperative fractures. All complications were effectively managed through appropriate treatment strategies. 3.Functional evaluation: Based on the ASAMI criteria, the excellent - to - good rate of bone outcomes in the FVFG group was 80.0%, while the BL group demonstrated superior results (p = 0.028). The excellent - to - good rate of limb function in the FVFG group was 36.6%, and there was no significant difference between the two groups (p = 0.537). CONCLUSION: For the treatment of femoral defects measuring ≥ 6 cm, single - segmental bone lengthening with the Orthofix external fixator exhibited advantages in terms of shorter operation time and reduced blood loss compared to FVFG combined with the Orthofix external fixator. Although other outcomes were comparable between the two groups, FVFG demonstrated broader applicability across diverse bone defect classifications, primarily constrained by the defect length and the vascular condition of the recipient site.