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Bioabsorbable fixation devices in orthopedic surgery with metal materials can not match advantage, it is the most popular of the past 30 years, scholars at home and abroad. However, due to the materials and workmanship, low initial mechanical properties, early degradation of speed, and can only be used for non-load-bearing bone internal fixation limbs long bone fixed, and can not be used. This study summarizes the research experience of the domestic and foreign scholars, human hair keratin (Human Hair Keratin, HHK) and medical polylactic acid (Polyactic Acid, PLA) as raw material, made by a certain percentage machining human hair keratin protein complex polylactic acid (HHK -PLA) fracture fixation rods, their detection and observation, to provide experimental basis for further research and clinical application. 【Objective】 1. Of their own study of human hair keratin composite polylactic acid (HHK-PLA) strength testing of fracture fixation rods mechanics were measured HHK-PLA shear force of the rod and the three-point bending force, to calculate the shear strength, bending strength and flexural modulus. 2. Understanding of human hair keratin composite bar fracture fixation in vivo degradation of polylactic acid (HHK-PLA), to observe the different stages of degradation rate. 3. Initial observation of human hair keratin compound fracture fixation rods biocompatibility of polylactic acid (HHK-PLA). 【Methods】 1. Using MTS-858 a Mini Bionix type biomechanical testing machine 20 hair keratin complex polylactic acid (HHK-PLA) fracture fixation rods test, shear strength and bending forces, and calculate the shear strength, flexural strength and flexural modulus. 2.36 HHK-PLA specimens were implanted the paraspinal subcutaneous tissue in the back of the 18 SD rats, respectively removed 1,2,4,8,12,16,20,24,28 weeks after measuring the weight loss, HHK-PLA degradation in SD rats. HHK-PLA specimen degradation of the structure after change is observed under a scanning electron microscope (SEM). Cut around HHK PLA specimens rat tissues, making tissue sections, observed tissue inflammation situation, understand HHK PLA material biocompatibility. [Results] 1. Human hair keratin (HHK PLA) the fracture fixation rod has good initial mechanical mechanical strength, shear strength 24lMpa, flexural strength of 358MPa polylactic acid composite flexural modulus 13Gpa. 2 human hair keratin (HHK PLA) fractures within the fixed bar in vivo degradation properties of polylactic acid composite slow early degradation rate, late degradation faster. Human hair keratin (HHK PLA) polylactic acid composite fracture fixation rods implanted in rats two weeks, fibrous tissue wrapped around the connective tissue hyperplasia, during telangiectasia, congestion, macrophages cells, plasma cells, neutrophils, fibroblasts and mononuclear cell infiltration. Gradually reduce the the HHK PLA specimen surrounding tissue inflammatory response after 8 weeks. After 12 weeks, HHK one PLA disappeared specimen surrounding tissue foreign body reaction, inflammatory cell infiltration. [Conclusion] human hair keratin (HHK PLA) fracture fixation rod has good initial mechanical mechanical strength of polylactic acid, to meet the limbs of the internal fixation. 2 human hair keratin (HHK PLA) fractures within the fixed bar in vivo degradation properties of polylactic acid composite slow early degradation rate, late degradation faster. This in vivo degradation characteristics conducive to fracture healing, the fracture did not heal, HHK PLA basically no degradation, played strong fixed until the fracture has healed, HHK PLA began to degradation. Human hair keratin (HHK PLA) polylactic acid composite fracture fixation rod has good biocompatibility early foreign body reaction, foreign body reaction gradually reduced after eight weeks, 12 weeks after surgery, HHK a PLA specimens surrounding tissue foreign body reaction disappeared.
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