BACKGROUND: An ideal repairing material characterizes by both great biocompatibility and osteogenesis ability. Any biomaterials should meet excellent biological security and biocompatibility prior to clinical application.OBJECTIVE: To evaluate the biocompatibility and the biological security of the TiO_2-Ag-nano-hydroxyapatite/polyamide66 (TiO_2-Ag-nHA/PA66) composite.DESIGN, TIME AND SETTING: A randomized controlled duplicated design was performed in Chongqing Medical University from July 2008 to July 2009.MATERIALS: A total of 40 Kunming mice aged 3 weeks and of clean grade and 32 healthy adult New Zealand rabbits were provided by Experimental Animal Center of Chongqing Medical University. TiO_2-Ag-nHA/PA66 composite powder (10 g),TiO_2-Ag-nHA/PA66 composites (n=32, 5 mm ×25 mm), and TiO_2-Ag-nHA/PA66 composites (n=32, 3 mm × 5 mm) were provided by Research Center of Nano-Biomaterials of Sichuan University.METHODS: General toxicity test: Forty mice were randomly divided into experimental and control groups. Composite powder was used to prepare leaching liquor which was treated on experimental mice by an intraperitoneal injection. While, an equal amount saline was inserted into the control mice. Intramuscular implanting test: The 16 rabbits were randomly divided into experimental and control groups. Two TiO_2-Ag-nHA/PA66 composite (5 mm × 25 mm) were implanted into left and right erector spinae, respectively. A similar surgery with the exception of implantation was performed on the control rabbits. Intrabony implanting test: The resting 16 rabbits were implanted one TiO_2-Ag-nHA/PA66 composite (3 mm × 5 mm) into left and right lateral epicondyle, respectively. Hemolytic test: A 8-mL anti-coagulation blood was obtained and added with composite powder (0.1,0.15, and 0.2 g).MAIN OUTCOME MEASURES: Biocompatibility and biological security of TiO_2-Ag-nHA/PA66 composite.RESULTS: General toxicity test demonstrated that mice in the two groups had good activity and eating, normal breathing, stable body mass, no paralysis, convulsion, and death. Intramuscular implanting test and intrabony implanting test showed that there was no significant difference in levels of alanine aminotransferase, aspartate transaminase, urea nitrogen, and creatinine and leukocyte numbers between the two groups before implantation and at day 4,1 week, and 2 weeks after implantation (P> 0.05).In particular, there was no significant difference in the experimental group at varying time points (P> 0.05). Intramuscular implanting test indicated that tissue sections in the experimental group displayed coated tissue of materials. The inflammatory variation in the experimental group was generally similar to that in the control group. Intrabony implanting test indicated that tissue sections in the experimental group displayed new bone formation. Hemolytic test suggested that hemolytic ratio of three varying concentrations of TiOrAg-nHA/PA66 composites was less than 5%, which met the normal criterion.CONCLUSION: TiO_2-Ag-nHA/PA66 composite has a good biocompatibility and biological security.

Objective To compare the clinical effects of extensive or limited arthroscopic debridement in varying degrees of knees osteo-arthritis. Methods 32 cases with knees osteoarthritis who underwent extensive debridement under arthroscopy were selected as the observa-tion group, and 30 cases with knees osteoarthritis who underwent limited debridement were selected as the control group. The excellent rate of joint function, Lysholm and VAS scores were compared between the two groups. Results The excellent rate of joint function were 90. 0%and 91. 4% in observation group and control group respectively, without significant difference (P>0. 05). Lysholm scores of patients with grade Ⅱ osteoarthritis was much higher in observation group than that in control group after operation (P<0. 05). There was no significant difference in Lysholm scores between gradeⅠand gradeⅢosteoarthritis (P>0. 05). No statistically significant difference of VAS scores on 1 year after operation were found (P>0. 05). Conclusion Extensive debridement and limited debridement under arthroscopy have similar effects for knees osteoarthritis. Extensive arthroscopic debridement is an ideal treatment method for Ⅱ grade of knees osteoarthritis.