ABSTRACT
We have designed a new kind of self-locking intramedullary nail for the treatment of unstable fracture of the middle and distal tibial shaft and have compared it with the interlocking nail by means of biomechanical experiments. The data could be used as a basis for clinical application. Fourteen formalin-fixed tibials of adults were made into unstable fracture models with a 2cm bone defect each. They were divided into 2 groups. Group 1 was fixed with self-locking intramedullary nail and group 2 was fixed by interlocking nail. All specimens were submitted to biomechanical test. The data were analysed by t test. The results showed there is no difference in anti-bending stiffness between the self-locking intramedullary nail and the interlocking nail. The anti-rotating and anti-compressing stiffness of interlocking nail is slightly better than that of self-locking intramedullary nail, but still the firmmess of the self-locking intramedullary nail in resisting rotation can meet the requirement of biological fixation. Its structure is reasonable, simple, practical, and it can resist certain harmful stress.