The Application Of Nano-hydroxyapatite/collagen In Bone Defects

Purpose: To observe the adverse reactions and the healing time and to evaluate the clinical effects of nano-hydroxyapatite/collagen (NHAC) as a bone graft substitute in repair of bone defects .Methods: Twenty-eight patients were treated with a bone graft substitute, NHAC for bone defects. Implantation amount was decided by extent of bone defects, averaging from 0.4 to 3.0 grams. They were divided into 3 groups. There were totally 22 cases in Group 1, all of them were bone defects caused by crushed fracture in upper and lower limbs. All of them underwent surgical procedure but had bone defects, so NHAC was implanted in them. There were totally 3 cases with nonunion of fractures in Group 2. After excising the scar and ossified tissue in fracture and reaming the marrow cavity, NHAC were implanted in .There were totally 3 cases with bone tumor-like defects in Group 3, including one case with fibrous dysplasia in upper tibia , another case with bone cyst in upper femur, the third one with patellar cyst. After excising the tumor-like tissue , NHAC was implanted in defects. Clinical and roentgenographic assessments were performed consecutively at follow-up periods 6 to 13 months.Results: All of 28 cases , the incision obtained the first rate union. Noadverse reactions to the graft materials were found in all patients except one case with fibrous dysplasia in upper tibia whose incision was found a little red and swelling in 3 weeks. Among the 22 cases with bone defects caused by fracture , 21 cases were followed up , 2 of them were re-fracture and with broken fixator , the reason was the early removal of the external fixator and trauma . The other 19 cases got clinical healing , and the healing time averaged from 3 to 6 months after operation. Among those 3 bone nonunion cases, during the time of 5 to 6 months after the operation, all of them got nearly clinical healing ,also. Among those 3 bone tumor-like defects cases, all cases were found new bone in the implatation parts 1 to 3 months later after operation and the density closed to that of normal bone tissue at 3 to 6 months. 3 cases got normal functions.Conclusion: NHAC has good biocompatibility and biodegradability. It is a safe^ effective bone graft substitute material for the filling of defects caused by different causes.