Introduction A recent histopathological and immunohistochemical study has proved that the addition of concentrated growth factors (CGF) to the Masquelet's technique contributes to the quality of the membrane formed, in respect of inducing inflammation and proliferation, maintaining vascularization on large diaphyseal bone defects, and increasing the number of stem cells. The aim of the study is comparison of radiological results of this combination treatment by micro-CT. Materials and methods The study was planned on a critical bone defect model in rabbit radius. Group I and Group III were the control groups to which only the Masquelet's technique is applied. Group II and Group IV were CGF groups in addition to the Masquelet's technique. CGF was prepared by centrifugation of rabbit's own blood. For early phase, Groups I and II were evaluated in the 8th week, while for late phase, Group III and Group IV were evaluated in the 12th week. Groups were compared in terms of bony union radiologically by micro-CT(mu CT) (New Bone Volume (NBV), Total Bone Volume (TBV) and NBV/TBV) and histopathologically. Results The structural parameters, including NBV, TBV, NBV/TBV were higher in the early- (8th week) and late-phase (12th week) CGF group. There was no statistically significant difference between CGF and control groups in early phase, (p = 0.153), while in late phase, CGF group was significantly higher of new bone volume than the control group, 246.3 mm(3)(196.1-258) and 169.6 mm(3)(154.3-235.9), respectively (p = 0.028). For early phase, control group was significantly lower than late-phase control group, 121.8 mm(3)(88.8-144.4) and 169.6 mm3 (154.3-235.9), respectively (p = 0.006). The ratio ofNew Bone VolumetoTotal Bone Volume(NBV/TBVratio) in CGF groups was significantly higher compared to the control groups 27.3% (24.7-29.6), 35.3% (32.1-38.6) (p = 0.032) and 39.7% (36.7-41.6), 55.3% (52-57.5) (p = 0.002), respectively. Histopathologically,Microscopic New Bone Formationhad no statistically significant difference between control and CGF groups in early phase (8th week) (p = 0.153), while in late phase (12th week), CGF group had significantly higher amount of new bone formation than the control group, 0.29 mu m(2)(0.27-0.36), 0.51 mu m(2)(0.42-0.59), respectively (p = 0.008). Conclusion The addition of CGF to the Masquelet's technique is an important method for supporting new bone formation in large diaphyseal bone defects. Level evidence Level III, therapeutic/care management.