Objective Bone defect repair remains a challenge in regenerative medicine, which has triggered a research upsurge on improving the bone repairing effect using heterogeneous bone combined with growth factors.The aim of this study was to evaluate local bone formation following surgical implantation of coralline hydroxyapatite (CHA), a heterogeneous bone, in combination with the concentrated growth factor (CGF).Methods This randomized prospective study included 24 New Zealand rabbits, which were equally divided into a CHA/CGF+CHA, a CHA/CGF+autograft and a CHA+autograft group.A defect 10 mm in diameter was made in the parietal bone of each animal and filled with CHA/CGF, CHA or autograft.At 6 and12 weeks after the operation, we observed the bone formation by micro-CT and histological examination.Results The bone volume (BV) was significantly higher in the CHA/CGF+CHA than in the CHA+autograft group both at 6 weeks ([39.00±7.61] vs [32.12±6.55] mm3, P<0.05) and at 12 weeks after the operation ([49.75±2.36] vs [39.45±7.02] mm3, P<0.05), and so was the bone mineral density (BMD) ([308.30±29.82] vs [256.85±151.25] mg/mL, P<0.05;[389.00±31.87] vs [302.53±127.05] mg/mL, P<0.05).Histological examination showed that the new bone was distributed throughout the CHA scaffold in the CGF/CHA group at 6 weeks, and the new bone was observed only in the periphery region of the CHA scaffold in the CHA group.The bone defects in the CGF/CHA group were fully repaired at 12 weeks, while those in the CHA group were partly repaired with bone and fibrous tissue in the central region of the defects.Conclusion Combination of CHA with CGF could effectively enhance bone healing.CHA/CGF compound artificial bone is an ideal substitute in bone transplantation.

Objective This study was to evaluate the clinical outcomes of orbital blowout fracture repair using the individual titanium mesh bent by computer-aided rapid prototyping . Methods The CT imaging data of 11 cases of orbital blowout fracture were analyzed.The subciliary approach was used for the exposure of the fractures .An appropriate 3D-printed titanium mesh pre-bent by computer-aided rapid prototyping was selected and implanted according to the characteristics of a given defect .The surgical results were analyzed by evaluating diplopia , eyeball movement , enophthalmos , and the position of the titanium mesh and comparing the orbital vol-ume before and after surgery . Results All the operations were successfully accomplished .No remolding or trimming was needed for the pre-bent titanium mesh and implanted titanium mesh was tightly fixed to the orbital wall .The patients were followed up for 3 -12 months, which revealed no symptoms of diplopia in any of the patients . Volumetric analysis showed a significantly reduced orbital volume difference from (2.60 ±0.43) mL preoperatively to (-0.07 ±0.62) mL postoperatively (P<0.01).Enophthalmos was desirably correc-ted, with the enophthalmos difference decreased from (2.35 ±0.81)mm preoperatively to (-0.10 ±0.52) mm postoperatively (P<0.01).No extra-ocular muscle limitation was observed . Conclusion The individual titanium mesh bent with computer-aided rapid prototyping technology can be applied to orbital blowout fracture repair , which may achieve a high success rate of anatomic restoration of the orbital volume and effective prevention of enophthalmos .