The Development Of Self-bring Interlocking Nail(SBIN)and Its Biomechanical Evaluation And Preliminary Clinical Application

Objective: A new kind of internal fixture, Self Bring Interlocking Nail (SBIN), was developed, which was easy to be used and could develop firm fixation for long bone fracture. In order to provide experiment and clinical data for safe clinical practice, the biomechanic test and preliminary clinical application were performed. Methods: The SBIN was designed according to biological fixation principle and made of 31 6L stainless steel. Six pairs of fresh adult moist cadaveric femur specimens were used to manufacture fracture model of femur shaft in low 1/3 part with 2cm bone defect and were divided into two groups. Group 1 was fixed using SBIN and KUntscher nail by turn. Group 2 was fixed by homemade interlocking nail and Ender's nail. Biomechanic test was performed on all specimens and the data were analysed by statistic SPSS software (GLM-General Factorial ANO VA). 16 cases with femur shaft fracture were treated by SBIN, the clinical results were divided into three groups according to Klemn's criteria. Results: The stiffness of SBIN in resisting to rotation and axial displacement were close to that of the homemade interlocking nail. But there was no significance between two nails (P>O.05) .The stiffness to resist bending of SBIN was larger than that of homemade interlocking nail significantly (P<0.0 1). The stiffness in resisting rotation, axial displacement and bending were larger than that of the Kuntscher nail and Ender's nail significantly (P<0.0 1). Excellent clinical results were obtained in 10 cases, good in 5 cases. The excellent and good rate was 93.8%. Conclusions: Being used in long bone fracture, the internal fixture of SBIN was firm, dependable and accorded with the principle of biological fixation. The instrument structure was in reason, safe, simple and practical .It could be widely used in clinical practice.