三种不同内固定方式治疗肱骨大结节骨折稳定性的体外力学分析

目的 对单纯肱骨大结节骨折的3种不同内固定方式(螺钉、张力带、肱骨大结节锁定钢板)进行生物力学测试，比较其稳定性，为临床肱骨大结节骨折内固定物的选择提供生物力学依据。方法 取18具保留肩袖肌的新鲜冰冻成人肱骨尸体标本，建立肱骨大结节骨折模型后，随机编号分为3组，分别采用螺钉、张力带及肱骨大结节锁定钢板技术固定大结节骨折块，牵拉冈上肌，测试力-位移曲线，记录2组参数：大结节移位5 mm时力的大小（load to 5 mm yield point, LtYP）及失效负荷（load to failure, LtF）。结果3组标本(螺钉组、张力带组、肱骨大结节锁定钢板组)在大结节移位5 mm时力的大小分别为(377±86)、(499±90)、(793±52) N，3组标本间LtYP差异有统计学意义（P<0.01）；两两比较，锁定钢板组LtYP远大于螺钉组（本研究中仅3例在内固定失效前位移达到5 mm），差异有统计学意义（P<0.01），锁定钢板组LtYP相比张力带组差异有统计学意义（P<0.01），张力带组LtYP相对螺钉组表现出明显的统计学意义（P<0.01）。3组标本失效负荷分别为(744±112)、(908±93)、(979±143) N，3组标本间LtF差异有统计学意义（P<0.01）；锁定钢板组LtF相对螺钉组具有明显的统计学意义（P<0.01），张力带组LtF相对螺钉组有统计学意义（P<0.01），但锁定钢板组LtF与张力带组之间无明显统计学差异（P>0.05）。结论 肱骨大结节锁定钢板组相对螺钉组及张力带组表现出明显的生物力学优势，锁定钢板将为临床治疗单纯肱骨大结节骨折提供新的、更好的选择。

Effect of three different fixation techniques on stability of greater tuberosity fractures of humerus

Objective To compare the stability of greater tuberosity fractures of humerus treated by three different fixation techniques (screws, tension band, locking plate, respectively) through biomechanical testing, so as to provide the biomechanics basis for choosing a better fixation in the clinical treatment for greater tuberosity fractures of humerus. Methods Standardized fracture models of the greater tuberosity from 18 fresh-frozen proximal humeri with intact rotator cuffs were created. The specimens were randomly assigned to 3 groups and treated by screws, tension band and locking plates, respectively. An increasing force was applied to the supraspinatus tendon. The force displacement curve and two parameters: LtYP(Load to 5 mm yield point) and Ltf(load to failure) were recorded. Results LtYP from the screw group, tension band group and locking plate group was (377±86), (499±90), (793±52) N, respectively, with significant differences among the three groups (P<0.01). Significant differences were also found between the groups as locking plate group (only 3 cases in locking plate group reached to 5 mm displacement before LtF in this study ) and screw group, locking plate group and tension band group, tension band group and screw group (P<0.01). LtF of screw group, tension band group and locking plate group was (744±112), (908±93), (979±143) N, respectively, showing significant differences among them, and which were also found between locking plate group and screw group, tension band group and screw group (P<0.01), but no significant differences were found between locking plate group and tension band group (P>0.05). Conclusions Locking plates show more obvious biomechanical stability than screws and tension band, which provides a new and better choice for treatment of isolated greater tuberosity fractures of humerus.