查看更多>>摘要：目的 通过有限元分析探讨胫骨远端内踝逆行髓内钉治疗胫骨远端粉碎性骨折的生物力学效果。 方法 选取解放军联勤保障部队第909医院体检的健康男性志愿者1名，30岁，身高172 cm，体质量60 kg。应用螺旋CT对左侧胫骨进行薄层连续扫描。将受试者胫骨CT数据导入Mimics 16.0软件建立胫骨三维模型。对胫骨三维模型远端进行切割，模拟胫骨远端粉碎性骨折，根据手术方式分别构建胫骨远端内侧钢板固定模型、专家型胫骨髓内钉固定模型、胫骨远端前外侧L形钢板固定模型、胫骨远端内踝逆行髓内钉固定模型。分别对4组模型依次施加400、800、1 200 N的压缩载荷及4、8、12 N·m的扭转载荷，观察4组模型在同种载荷下的等效应力和位移情况。 结果 在400、800、1 200 N压缩载荷条件下，胫骨远端内侧钢板固定模型最大应力分别为35.08、69.26、103.52 MPa，专家型胫骨髓内钉固定模型最大应力分别为24.45、46.26、71.00 MPa，胫骨远端前外侧L形钢板固定模型最大应力分别13.69、27.76、34.10 MPa，胫骨远端内踝逆行髓内钉固定模型最大应力分别为16.07、28.91、41.25 MPa。胫骨远端内侧钢板固定模型的应力峰值高于另外3组，专家型胫骨髓内钉固定模型的应力峰值处于中等水平，而胫骨远端内踝逆行髓内钉固定模型的应力峰值以及胫骨远端前外侧L形钢板固定模型的应力峰值较低且相近。在3种压缩载荷情况下，胫骨远端内侧钢板固定的位移峰值分别为0.65、1.28、1.90 mm，专家型胫骨髓内钉固定分别为0.69、1.36、2.04 mm、前外侧L形钢板固定分别为0.65、1.28、1.91 mm，胫骨远端内踝逆行髓内钉固定分别为0.68、1.34、2.01 mm，4种不同的内固定方式所导致的位移峰值接近。在4、8、12 N·m扭转载荷条件下，胫骨远端内侧钢板固定模型的最大应力分别为284.66、568.87、950.00 MPa，专家型胫骨髓内钉固定模型的最大应力分别为187.74、373.06、558.19 MPa，胫骨远端前外侧L形钢板固定模型的最大应力分别为219.75、439.50、649.01 MPa，胫骨远端内踝逆行髓内钉固定模型的最大应力分别为194.45、368.32、544.89 MPa。胫骨远端内侧钢板固定应力峰值最大，胫骨远端前外侧L形钢板固定于居中水平，而胫骨远端内踝逆行髓内钉固定和专家型胫骨髓内钉固定显示出较低且相似的应力峰值。在4、8、12 N·m扭转载荷下，胫骨远端内侧钢板固定的位移峰值（3.37、6.67、11.12 mm）也比专家型胫骨髓内钉固定（2.49、5.01、7.51 mm）、前外侧L形钢板固定（2.36、4.73、7.12 mm）和胫骨远端内踝逆行髓内钉固定（1.32、2.62、3.92 mm）更高。专家型胫骨髓内钉固定和胫骨远端前外侧L形钢板固定位移峰值位于居中水平且相近，而胫骨远端内踝逆行髓内钉固定的位移峰值较低。 结论 采用远端胫骨内踝逆行髓内钉固定治疗胫骨远端粉碎性骨折相对传统的内固定方法，生物力学稳定性更好，更安全可靠，推荐临床首选。 Objective This study aimed to investigate the biomechanical effect of retrograde intramedullary nail in the treatment of comminuted fracture of distal tibia by finite element analysis. Methods A 30-year-old healthy male volunteer with 172 cm height and 60 kg weight was selected in the 909th Hospital of PLA. Thin-layer continuous scanning of the entire tibia was performed using helical computed tomography. On the basis of the tibia CT data, a 3D model of the tibia was constructed using digital medical software. The distal tibia was segmented to simulate a comminuted distal tibia fractures, and each model was fixed using one of the above four fixation methods. All four models were applied with the same constraints, vertical axial loads of 400, 800, and 1200 N, and torsional loads of 4, 8, and 12 N·m. The equivalent stress and displacement of the models under different fixation methods were observed. Results Under the compression load of 400, 800, and 1 200 N, the maximum stress of the distal medial tibial plate was 35.08, 69.26, and 103.52 MPa, respectively that of the expert-type tibial intramedullary nail was 24.45, 46.26, and 71.00 MPa, respectively that of the anterolateral L-shaped plate at the distal tibia was 13.69, 27.76, and 34.10 MPa, respectively and that of the retrograde intramedullary nail at the distal tibia malleolus was 16.07, 28.91, and 41.25 MPa. The stress peak value of distal medial tibial plate fixation was significantly higher than that of the other three groups. The expert-type tibial intramedullary nail fixation had a moderate effect, and the distal tibial medial malleolar retrograde intramedullary nail fixation and distal tibial anterolateral L-shaped plate fixation had a low effect and produced similar stress peaks. Under the three compression loads, the difference of peak displacement caused by the four different internal fixation methods was very small. Under the torsional load of 4, 8, and 12 N·m, the maximum stress of the distal medial steel plate of tibia was 284.66, 568.87, and 950.00 MPa, respectively that of the expert-type tibial intramedullary nail was 187.74, 373.06, and 558.19 MPa, respectively that of the anterolateral distal tibial L-shaped plate was 219.75, 439.50, and 649.01 MPa, respectively and that of the retrograde intramedullary nail at the distal tibial malleolus was 194.45, 368.32, and 544.89 MPa, respectively. The peak value of fixed stress in the distal medial tibial plate was the highest. The distal tibial anterolateral L-shaped plate was fixed at the median level, and the distal tibial medial malleolar retrograde and expert tibial intramedullary fixations showed low and similar stress peaks. Under the torsional loads of 4, 8, and 12 N·m, the peak displacement of the distal medial tibial plate fixation (3.37, 6.67, and 11.12 mm) was also higher than those of the expert tibial intramedullary nails (2.49, 5.01, and 7.51 mm), anterolateral L-shaped plates (2.36, 4.73, and 7.12 mm) and distal tibial medial malleolus retrograde intramedullary nail fixation (1.32, 2.62, and 3.92 mm). The expert tibial intramedullary nail fixation and distal tibial anterolateral L-shaped plate fixation were located at the median level and had similar peak displacement. Meanwhile, the peak displacement of distal tibial medial malleolar retrograde intramedullary nail fixation was low. Conclusion The treatment of comminuted fracture of distal tibia with retrograde intramedullary nail-fixation of distal tibia medial malleolus has better biomechanical stability, safer and more reliable than the traditional internal fixation method, and which is recommended as the first choice in clinic.
万方数据