| Objective: To study the biomechanical characters of Humerus Self-locking Intramedullary Nail(HSLIN) which is a new type of intramedullary nail consisting of the antegrade and retrograde nail types designed on the basis of previous intramedullary nail and to provide the basic proof for clinical practice and to evaluate its preliminary clinical application. Methods: HSLIN is composed of a main nail, a interior mandril, four locking-sheets and a fixation nut.Six fresh humeral shafts of adult were fracture on purpose.Then fixed the fractures with HSLIN made of 317L stainless steel and took the test of biomechanics.The stiffness of single locking-sheet and interior mandril also were test to resist twisting momentum.39 cases patients of humerus shaft fracture were treated with HSLIN,of whom 15 cases were treated with antegrade HSLIN and 24 cases with retrograde HSLIN.The results were evaluated based on a criteria including clinical and radiographic parameters. Result: HSLIN resisted certain curving,twisting,pulling force,which might meet biomechanic needs.With an average of 13.4 months(range 6~24 months)of follow-up,all cases acquired bony union with mean union time 13 weeks(range 9~24 weeks).According to the criteria,27 patients were evaluated as having excellent result, 10 good.The overall excellent or good rate was 94.9%.The recovery of shoulder function was excellent in 27 cases,good in 4 cases,and fair in 2 cases,and the overall excellent or good rate was 94.9%.The recovery of elbow function was excellent in all cases.5 cases had shoulder impingement caused by the tail of HSLIN. Conclusion: HSLIN is in accordance with the humerus medullary cavity shape and biomechanics of human body. HSLIN belonging to the well-organized combination of flexible fixation and firm fixation,has lower shelter,benefits the bone,and has many other advantages,such as less trauma and good results, reasonable structure and simple manipulation , without X-ray guidance. |
PDF Full Text Request