Kawamura Tadashi, Minehara Hiroaki, Tazawa Ryo, Matsuura Terumasa, Sakai Rina, Takaso Masashi
Department of Orthopaedic Surgery, Kitasato University School of Medicine, Minami-ku, Sagamihara, Kanagawa, Japan.
Department of Medical Engineering and Technology, Kitasato University, Minami-ku, Sagamihara, Kanagawa, Japan.
Geriatr Orthop Surg Rehabil. 2021 Feb 25;12:2151459321998611. doi: 10.1177/2151459321998611. eCollection 2021.
The failure rate of operations involving the cephalomedullary nail technique for unstable femoral trochanteric fractures is 3-12%. Changing the reduction strategy may improve the stability. This study aimed to confirm whether reducing the proximal fragment with the medial calcar contact, as opposed to utilizing an intramedullary reduction, would improve the stability of such fractures.
The unstable femoral trochanteric fracture model was created with fixation by cephalomedullary nails in 22 imitation bones. The 2 reduction patterns were as follows: one was with the proximal head-neck fragment external to the distal bone in the frontal plane and anterior in the sagittal plane as "Extramedullary," while the other was the opposite reduction position, that is, bone in the frontal plane and sagittal plane as "Intramedullary." We evaluated the tip-apex distance, compression stiffness, change in femoral neck-shaft angle, amount of blade telescoping, and diameter of the distal screw hole after the compression test. Statistical analysis was conducted using the Mann-Whitney U test.
No significant differences were seen in compression stiffness ( = 0.804) and femoral neck-shaft angle change ( = 0.644). Although the "Extramedullary" tip-apex distance was larger than the "Intramedullary" distance ( = 0.001), it indicated clinically acceptable lengths. The amount of blade telescoping and the distal screw hole diameter were significantly larger in "Intramedullary" than in "Extramedullary" ( < 0.001, = 0.019, respectively). Our results showed that "Intramedullary" had significantly larger blade telescoping and distal screw hole diameters than "Extramedullary," and contrary to our hypothesis, no significant differences were seen in compression stiffness and femoral neck-shaft angle change.
As opposed to the "Intramedullary" reduction pattern, the biomechanical properties of the "Extramedullary" reduction pattern improved stability during testing and decreased sliding.
使用股骨近端髓内钉技术治疗不稳定型股骨转子间骨折的手术失败率为3% - 12%。改变复位策略可能会提高稳定性。本研究旨在确认与髓内复位相比，通过内侧骨皮质接触复位近端骨折块是否能提高此类骨折的稳定性。
在22根模拟骨上使用股骨近端髓内钉固定建立不稳定型股骨转子间骨折模型。两种复位方式如下：一种是在额状面近端头颈骨折块位于远端骨外侧且矢状面前方，称为“髓外”；另一种是相反的复位位置，即在额状面和矢状面骨折块位于远端骨内侧，称为“髓内”。我们评估了尖顶距、压缩刚度、股骨颈干角变化、刀片伸缩量以及压缩试验后远端螺钉孔直径。采用曼 - 惠特尼U检验进行统计分析。
压缩刚度（P = 0.804）和股骨颈干角变化（P = 0.644）未见显著差异。虽然“髓外”尖顶距大于“髓内”尖顶距（P = 0.001），但其长度在临床上可接受。“髓内”的刀片伸缩量和远端螺钉孔直径显著大于“髓外”（分别为P < 0.001，P = 0.019）。我们的结果表明，“髓内”的刀片伸缩量和远端螺钉孔直径显著大于“髓外”，与我们的假设相反，压缩刚度和股骨颈干角变化未见显著差异。
与“髓内”复位方式相比，“髓外”复位方式在测试过程中的生物力学性能提高了稳定性并减少了滑动。
