FUNDAMENTALSSpontaneous Bone Regeneration in Surgically Induced Bone Defects in Young RabbitsSong, Hae-Ryong M.D.*; Puri, Ajay M.D.*; Lee, Jeong-Hee M.D.†; Park, Hyung-Bin M.D.*; Ra, Do-Kyung D.V.M.§; Kim, Gon-Sup D.V.M., Ph.D.§; Yeon, Seong-Chan D.V.M.Ph.D.§Author Information *Department of Orthopaedic Surgery †Department of Pathology, School of Medicine §School of Veterinary Medicine, Gyeong-Sang National University, Chinju, Korea Address correspondence and reprint requests to Dr. H. R. Song, Department of Orthopaedic Surgery, School of Medicine, Gyeong-Sang National University, 92 Chilam-dong, Chinju 660-702, Republic of Korea Journal of Pediatric Orthopaedics B: October 2002 - Volume 11 - Issue 4 - p 343-349 Buy Abstract Defects of the femoral shaft (15%, 20%, 25%, and 30% of the femoral length) with intact periosteum were made in young rabbits to investigate differences in union time. The mean union time was 7.3, 7.1, 7.4, and 7.0 weeks, respectively and there was no significant difference (P >0.05) between the groups. The mean healing indices were 6.7, 4.6, 3.9, and 3.1 weeks/cm, respectively and these were significantly different (P <0.05) between the 15% bone defect group and the other bone defect groups. These results suggested that union time was not affected by the amount of bone defect. Femoral lengthening of 20% was performed to compare the quality of callus with those of the femoral defect of 20%. The mean healing indices of defect and lengthening were 4.6 and 5.7, respectively and the difference was significant (P = 0.004). The callus stiffness of femoral defect was higher (P = 0.02) than that after femoral lengthening whereas the bone mineral density of the callus showed no significant difference (P = 0.37) between two groups. The method of filling bone defect with callus generated from the intact periosteum may be a new therapeutic option for the reconstruction of large bone defects in children when other treatments are not available. © 2002 Lippincott Williams & Wilkins, Inc.