The changes of collagen architecture of cortical bone beneath swan-like memory connector fixation in rabbit fracture model

Objective To investigate the changes of collagen architecture of cortical bone beneath swan-like memory connector(SMC) fixation in rabbit fracture model.Methods Bilateral humerus of 20 rabbits were osteotomized in midshaft.One side was randomly fixed with SMC as experimental group,and contralateral was plated by the 4-hole dynamic compress plate(DCP) as control group.At the 2,4,8,16,32 weeks after operations,the cortical bone of humerus beneath fixation in 4 rabbits were harvested for scanning microscopic observation.Results No regional osteoporosis and collagen disorganization were found in SMC group during the whole experimental process.In 4 weeks after operation,the collagen architecture of cortical bone in DCP group began to show collagen fiber disorganization and resoption cavites.Along with fixation the longer,the degree of osteoporosis and bone resorption became worse gradually.Conclusion SMC has plenty of advantages in material and geometrical conformation these characteristics of SMC are beneficial not only to preventing stress shielding,but also compromise perfusion of bone less,so SMC can effectively diminish osteoporosis beneath fixation.