Park Si Young, Park Jin, Rhee Dong Joo, Yoon Han Kook, Yang Kyu Hyun
Department of Orthopaedic Surgery, Yonsei University, College of Medicine, Seoul, Republic of Korea.
Injury. 2007 Jul;38(7):785-91. doi: 10.1016/j.injury.2007.03.010. Epub 2007 May 30.
We investigated the sliding pattern characteristics of proximal fragment in 16 proximal femur models of 31-A2.1 type trochanteric fractures fixed with dynamic hip screw system under load. In eight models, the lag screw was inserted with an anterior-to-posterior vector within the neck and the head of femur (group 1). The other eight had a posterior-to-anterior vector (group 2). A force of 500 N (30 cycles) was applied to the fracture fragment-plate complex using the Instron 6022. No significant difference was noted in the sliding distance between the two groups (p=0.17). However, the mean angle of rotation of the proximal fragment was twice as great in group 1 (16+/-3.7 degrees ) than that in group 2 (8.1+/-1.5 degrees ) (p<0.001). In group 1, early eccentric contact in the anterior aspect of the intertrochanteric area caused internal rotation of the proximal fragment. Breakage of the anterior cortex of the lateral wall was noted in five out of the eight cases in group 1 and no case in group 2 (p=0.026). Fracture of the anterior cortices significantly threatened the integrity of the lateral wall in group 1.
我们研究了16个31 - A2.1型股骨转子间骨折近端模型在负载下使用动力髋螺钉系统固定时近端骨折块的滑动模式特征。在8个模型中，拉力螺钉经股骨颈和股骨头从前向后置入（第1组）。另外8个模型中，拉力螺钉经股骨颈和股骨头从后向前置入（第2组）。使用Instron 6022对骨折块 - 钢板复合体施加500 N的力（30个循环）。两组之间的滑动距离无显著差异（p = 0.17）。然而，第1组近端骨折块的平均旋转角度（16±3.7度）是第2组（8.1±1.5度）的两倍（p < 0.001）。在第1组中，转子间区域前方的早期偏心接触导致近端骨折块内旋。第1组8例中有5例出现外侧壁前侧皮质断裂，第2组无1例出现（p = 0.026）。第1组中前侧皮质骨折显著威胁到外侧壁的完整性。
