Orthopedic Trauma Division, Trauma Center, Gachon University College of Medicine, Namdong-gu, Incheon, South Korea.
Department of Orthopedic Surgery, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea.
J Orthop Sci. 2021 Mar;26(2):266-270. doi: 10.1016/j.jos.2020.03.005. Epub 2020 Mar 30.
Depending on the size of the proximal bone segment, either a standard locking construct or a recon locking construct can be used in intramedullary nailing for a subtrochanteric fracture. However, the most appropriate construct for a given size of proximal bone segment has not yet been determined. Therefore, this study aimed to identify the appropriate construct using biomechanical testing.
Fourteen intramedullary nails for each locking construct (standard and recon) were inserted into 28 synthetic femurs. Fourteen subtrochanteric fracture models were developed by creating parallel defects (2 cm in size) 2 cm distal to the lower edge of the lesser trochanter (low fracture group), and 14 fracture models were developed with identical defects situated 1 cm distal to the lower edge of the lesser trochanter (high fracture group). An axial load experiment was conducted to measure the stiffness and failure load for each proximal interlocking screw construct.
There were no statistically significant differences in the stiffness and failure load between the locking constructs in the low fracture group. However, the stiffness and failure load were significantly greater for the recon locking construct than for the standard locking construct in the high fracture group.
The standard locking system allows for sufficient fixation strength when performing intramedullary nailing for subtrochanteric fractures located 2 cm distal to the lower edge of the lesser trochanter.
根据近端骨段的大小，可以在髓内钉治疗转子下骨折中使用标准锁定结构或重建锁定结构。然而，对于给定大小的近端骨段，最合适的结构尚未确定。因此，本研究旨在通过生物力学测试来确定合适的结构。
将每种锁定结构（标准和重建）的 14 根髓内钉插入 28 个合成股骨中。通过在下小转子下缘下方 2cm 处创建平行缺损（大小为 2cm）来开发 14 个转子下骨折模型（低骨折组），并通过在小转子下缘下方 1cm 处创建相同的缺损来开发 14 个骨折模型（高骨折组）。对每个近端锁定螺钉结构进行轴向加载实验，以测量其刚度和失效载荷。
在低骨折组中，锁定结构的刚度和失效载荷之间没有统计学上的显著差异。然而，在高骨折组中，重建锁定结构的刚度和失效载荷明显大于标准锁定结构。
在对位于小转子下缘下方 2cm 的转子下骨折进行髓内钉治疗时，标准锁定系统允许足够的固定强度。
