Objective: To investigate ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury by using a biomechanical test.
Methods: A total of 24 ankle specimens from adult cadavers were used as the tibiofibular syndesmosis injury model. According to the angle of screw placement, the tibiofibular syndesmosis injury models were randomly divided into groups A (0°), B (10°-15°), C (20°-25°), and D (30°-35°), and the screws were placed at a level 2 cm proximal to the ankle joint. The displacement of fibula was measured by biomechanical testing machine at neutral, dorsiflexion (10°), plantar flexion (15°), varus (10°), and valgus (15°) positions, with axial load of 0-700 N (pressure separation test). The displacement of fibula was also measured at neutral position by applying 0-5 N·m torque load during internal and external rotation (torsional separation test).
Results: In the pressure separation test, group C exhibited the smallest displacement under different positions and load conditions. At neutral position, significant differences were observed ( P<0.05) between group A and group C under load of 300-700 N, as well as between group B and group C under all load conditions. At dorsiflexion position, significant differences were observed ( P<0.05) between group A and group C under load of 500-700 N, as well as between groups B, D and group C under all load conditions, and the displacements under all load conditions were significantly smaller in group A than in group B ( P<0.05). At plantar flexion position, significant differences were observed ( P<0.05) between group D and group C under all load conditions. At valgus position, significant differences were observed ( P<0.05) between group A and group C under load of 400-700 N, as well as between groups B, D and group C under all load conditions. In the torsional separation test, group C exhibited the smallest displacement and group B had the largest displacement under different load conditions. During internal rotation, significant differences were observed ( P<0.05) between group B and group C under all load conditions, as well as between group D and group C at load of 3-5 N·m. During external rotation, significant differences were observed between groups B, D and group C under all load conditions ( P<0.05). No significant difference was detected between groups at the remaining load conditions ( P>0.05).
Conclusion: The ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury was 20°-25°, which has a small displacement of fibula.
目的: 通过生物力学试验探讨下胫腓联合损伤重建术中螺钉理想植入角度。.
方法: 选取24个成年尸体踝关节标本制备下胫腓联合损伤模型后，根据螺钉植入角度随机分为A（0°）、B（10°～15°）、C（20°～25°）、D（30°～35°）组，分别在离踝关节近端2 cm水平处植入螺钉。采用生物力学试验机，在中立、背伸（10°）、跖屈（15°）、内翻（10°）和外翻（15°）位，施加0～700 N轴向载荷，测量腓骨位移（压力分离试验）；在中立位以内旋和外旋施加0～5 N·m扭矩载荷，测量腓骨位移（扭矩分离试验）。.
结果: 压力分离试验中，不同体位及载荷条件下，C组位移均最小。中立位时，A组300～700 N载荷条件下、B组各载荷条件下位移与C组比较，差异有统计学意义（ P<0.05）；背伸位时，A组500～700 N载荷下、B组及D组各载荷条件下位移与C组比较，差异有统计学意义（ P<0.05），而A组各载荷条件下位移均小于B组（ P<0.05）；跖屈位时，D组各载荷条件下位移与C组比较，差异有统计学意义（ P<0.05）；外翻位时，A组400～700 N载荷条件下、B组及D组各载荷条件下位移与C组比较，差异有统计学意义（ P<0.05）。扭矩分离试验中，不同载荷条件下C组位移最小、B组最大。内旋时，B组各载荷条件下、D组3～5 N·m载荷条件下位移与C组比较，差异有统计学意义（ P<0.05）；外旋时，B组和D组各载荷条件下位移与C组比较，差异有统计学意义（ P<0.05）。其余条件下各组间差异均无统计学意义（ P>0.05）。.
结论: 下胫腓联合损伤重建术中螺钉植入理想角度为20°～25°，以该角度植入螺钉固定后腓骨位移更小。.
Keywords: Tibiofibular syndesmosis injury; biomechanics; implant angle; screw fixation.