Four cannulated screws in self-designed configurations for fixation of extremely unstable femoral neck fractures: a biomechanical analysis
10.3760/cma.j.issn.1671-7600.2019.02.011
- VernacularTitle:新构型四枚空心钉固定极不稳定型股骨颈骨折生物力学分析
- Author:
Yanbin LIN
1
;
Guangshu YU
;
Zhihui ZHONG
;
Zhaoqing SHEN
;
Wei ZHENG
;
Yan ZHUANG
;
Yangkai XU
Author Information
1. 厦门大学附属福州第二医院骨科
- Keywords:
Femoral neck fractures;
Fracture fixation;
internal;
Bone nails;
Biomechanics
- From:
Chinese Journal of Orthopaedic Trauma
2019;21(2):160-165
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the biomechanical properties of our self-designed 4 cannulated screws in 4 configurations for fixation of extremely unstable femoral neck fractures.Methods Twelve adult cadaveric femoral specimens were randomly divided into 4 equal groups (n =3) and made into models of extremely unstable femoral neck fracture combined with comminution (Pauwels type Ⅲ).Group A was subjected to fixation in configuration of “double axial compressions plus double stabilizations”,group B to configuration of “positive triangle parallel compression plus small angle screwing”,group C to configuration of “inverted triangle parallel compression plus small angle screwing”,and group D to configuration of “diamond pattern screwing”.Static compression tests,cyclic loading tests and limit load tests were carried out for the 4 groups on a biomechanical testing machine.Results For groups A,B C and D,the axial compression stiffness was respectively 995.29 ±34.16 N/mm,509.89 ± 138.90 N/mm,559.28 ± 111.25 N/mm and 610.18 ±232.35 N/mm,and the limit load was respectively 3,225.33 ±461.31 N,2,008.67 ±237.27 N,2,705.67 ±496.39 N and 2,395.33 ±403.71 N,showing significant differences between the 4 groups (P ＜ 0.05).For groups A,B C and D,the displacement was respectively 0.46 ± 0.10 mm,1.47 ± 0.72 mm,1.14 ±0.24 mm and 1.22 ±0.22 mm,and the limit stiffness was respectively 1,139.28 ±342.09 N/mm,843.56 ±408.91 N/mm,585.98 ± 81.60 N/mm and 729.96 ±251.37 N/mm,showing no significant differences between the 4 groups (P ＞ 0.05).Conclusions In the fixation of extremely unstable femoral neck fracture with our self-designed 4 cannulated screws,the configuration of “double axial compressions plus double stabilizations” may lead to the greatest biomechanical advantage while the configuration of “positive triangle parallel compression plus small angle screwing” may result in the poorest biomechanical properties.
