锁定钢板以不同偏转角度固定股骨干粉碎骨折的有限元分析
发布时间：2018-08-03 15:02
【摘要】：目的:结合锁定螺钉的桥接接骨板是目前治疗股骨干粉碎骨折的常见内固定器材之一,在良好的骨折端复位的前提下尽量使用闭合复位内固定技术已成为治疗共识,然而在临床实践中,闭合复位后放置钢板时,由于暴露不够充分,会出现接骨板中线与股骨长轴成角度固定。本研究通过运用三维有限元分析技术,模拟粉碎骨折斜置钢板固定,对其固定的力学效果进行对比及评价,以及探讨斜置钢板固定股骨粉碎骨折的风险,从而为临床治疗提供理论依据。方法:利用64排螺旋CT扫描正常成年人股骨,获取股骨DICOM数据,将DICOM数据导入Mimics医学建模软件进行三维重建,并建立股骨干粉碎骨折模型;运用Pro/E Wildfire 5.0软件,依据股骨解剖锁定钢板建立接骨板模型,将此模型STL文件导入Mimics,同时结合股骨粉碎骨折模型进行模拟内固定手术,然后将钢板分别置于不同偏转角度,依据近端螺钉偏前及偏后分为接骨板前倾及后倾两组,每组分别依据远近端螺钉距离皮质的距离分为2mm、4mm、6mm、8mm、10mm五个亚组,以及加上正常中置钢板总共11组。分别通过3-matic及Mimics进行网格划分和赋值,对各个内固定模型施加模拟70kg成人双足站立时的载荷及约束,观察各个分组间的股骨及内植物的等效应力、位移的分布变化。结果:对于各个亚组在相同的载荷及约束下,随钢板倾斜程度的增大,斜置组1、5、6号钉-骨界面的应力峰值逐渐递增:(1)在前倾2组及前倾4组中1、5、6号钉孔处骨皮质均出现了应力集中且大于股骨皮质的强度。在前倾6组中,5、6号钉孔皮质出现了应力集中,且大于股骨皮质的强度;(2)在后倾2组、后倾4组、后倾6组中的1号、5号及6号钉孔处骨皮质和后倾8组中的5号、6号钉孔处骨皮质出现应力集中且超过骨皮质的强度;(3)在各个亚组中,锁定钢板及螺钉的峰值应力及应变均位于3号螺钉的钉-板交界处,且未超出钛合金的强度;(4)在钢板前倾组,随钢板倾斜程度的增大,骨折断端轴向位移增大;(5)在钢板后倾组,随钢板倾斜程度的增大,轴向位移减小,剪切位移增大。结论:股骨锁定钢板近端向前倾斜放置时,当螺钉距离骨皮质表面小于等于6mm时,在负重的过程中,最远端两个螺钉会因螺钉附近骨质破坏而失去把持力;当螺钉距离骨皮质距离小于4mm时,最远端的两个螺钉及近端螺钉处的骨皮质存在疲劳断裂的可能,会导致远近端螺钉同时失效导致内固定失败;股骨锁定钢板近端向后倾斜放置时,当螺钉距离骨皮质表面小于8mm时,在负重的过程中,最远端两个螺钉会因螺钉附近骨质破坏而失去把持力;当螺钉距离骨皮质小于6 mm时,最远端的两个螺钉及近端螺钉处的骨皮质存在疲劳断裂的可能,会导致远近端螺钉同时失效导致内固定失败;钢板前倾放置后在负重后会导致骨折断端轴向稳定性下降,而钢板后倾后负重会导致其骨折断端剪切向稳定性大大降低,同样不利于骨折愈合。以上结论提示我们在利用MIPO技术处理股骨干部位的粉碎骨折时,出于固定效果的考虑,应当尽量将钢板与股骨干长轴平行放置,以获得最佳的固定效果。当术中放置钢板后,钢板近端向前倾斜时,则应保证其远近端螺钉距离骨皮质表面均应大于6mm,而当钢板近端向后倾斜放置时,其远近端螺钉距离骨皮质表面均应大于8mm,否则在术后恢复期的功能锻炼存在钢板周围骨折的风险。如钢板放置后虽然倾斜,但在上述安全范围内,则可以不需反复调整钢板位置,以避免过度损伤软组织、破坏骨折断端血运,避免不必要的医源性辐射的损害。钢板倾斜放置时,骨折断端的微动均大于钢板与股骨纵轴平行放置的情况,因此骨折愈合前应避免下地负重以避免骨折不愈合。
[Abstract]:Objective: the bridging plate combined with locking screws is one of the common internal fixators for the treatment of femoral shaft comminuted fractures. The closed reduction and internal fixation technique has become a common understanding on the premise of good fracture reduction. However, in clinical practice, when the plate is placed after closed reduction, the exposure is not sufficiently exposed. In this study, the three-dimensional finite element analysis (3D finite element analysis) was used to simulate the fixation of the comminuted fracture of the steel plate, to compare and evaluate the mechanical effect of the fixation, and to explore the risk of the fixation of the femoral fracture with oblique plate, and to provide a theoretical basis for clinical treatment. Method: 64 Spiral CT scan normal adult femur, obtain femur DICOM data, introduce DICOM data into Mimics medical modeling software for three-dimensional reconstruction, and establish the model of femoral shaft comminuted fracture; use Pro/E Wildfire 5 software to establish the plate model based on the locking plate of femur, and introduce this model STL file into Mimics, and combine the femur with the femur. The fracture model was performed by simulated internal fixation, and then the plate was placed at different deflection angles. According to the anterior and posterior partial screws, the two groups were divided into two groups, which were the anterior and posterior inclination of the plate. Each group was divided into five subgroups of 2mm, 4mm, 6mm, 8mm, 10mm respectively according to the distance of the distant and proximal screw distance cortex, and 11 groups were added to the normal medium plate. Grid division and assignment were carried out through 3-matic and Mimics respectively, and the load and constraint of simulated 70kg adult bipedal standing were applied to each internal fixation model. The equivalent stress and displacement of the femur and inner plant between the groups were observed. The stress peak value of 1,5,6 nail bone interface increased gradually in the oblique group: (1) the stress concentration of the bone cortex appeared in the 2 groups and the front 4 groups, and the intensity of stress concentration was greater than that of the femoral cortex. In the 6 groups, the stress concentration of the 5,6 nail hole cortex appeared, and was greater than the strength of the femoral cortex; (2) in the 2 groups, the backward 4 groups, and the posterior inclination 6. In the group 1, No. 5 and No. 6, the cortical bone and the 8 groups of the posterior tilt were 5. The cortical bone cortex appeared stress concentration and exceeded the strength of the bone cortex. (3) in each subgroup, the peak stress and strain of the locking plate and screw were located at the nailed plate junction of No. 3 screw and did not exceed the strength of the titanium alloy; (4) (4) in the steel plate forward group, (4) The axial displacement of the broken end of the fracture increased, and (5) the axial displacement decreased and the shear displacement increased as the steel plate tilted. Conclusion: when the proximal end of the locking plate of the femur is placed forward, when the distance of the screw is smaller than 6mm, the two most distal screw will be in the process of weight negative. When the distance of the screw distance to the bone is less than 4mm, the bone cortex of the two distal screws and the proximal screws may have fatigue fracture when the distance of the screw is less than the cortical bone, which leads to the failure of the internal fixation of the distal end screw and the proximal end of the locking plate when the screw is placed in the bone cortex. When the surface is less than 8mm, the most distal two screws will lose the holding force due to the bone destruction near the screw during the loading process. When the screw is less than 6 mm, the bone cortex of the distal two screws and the proximal screws may have fatigue fracture, which will lead to the failure of the internal fixation of the distal end screw and the plate before the screw. After placing weight, the axial stability of fracture end will decrease after loading, and the weight of the plate behind the plate will lead to the reduction of the fracture end of the fracture to the stability, which is also not conducive to the fracture healing. The above conclusion suggests that we should use the MIPO technique to deal with the broken bone fracture in the femoral shaft. The plate should be placed in parallel with the long shaft of the femoral shaft to obtain the best fixation effect. When the steel plate is placed during the operation, the proximal end of the plate should be more than 6mm when the proximal end of the plate is tilted forward, and the distance to the proximal end screw should be greater than 8mm when the proximal end of the plate is tilted. Otherwise, the distal end screw of the plate should be greater than that of the bone. In the post recovery period, there is a risk of fracture around the plate. If the plate is placed after the plate is placed, the position of the steel plate can not be repeatedly adjusted to avoid excessive damage to the soft tissue, damage the fractured end blood transport and avoid unnecessary iatrogenic radiation damage. When the steel plate is tilted, the fracture ends micro The movement is greater than that of the plate placed parallel to the longitudinal axis of the femur, so the lower weight bearing should be avoided before fracture healing to avoid nonunion.
【学位授予单位】：天津医科大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.3
本文编号：2162117
[Abstract]:Objective: the bridging plate combined with locking screws is one of the common internal fixators for the treatment of femoral shaft comminuted fractures. The closed reduction and internal fixation technique has become a common understanding on the premise of good fracture reduction. However, in clinical practice, when the plate is placed after closed reduction, the exposure is not sufficiently exposed. In this study, the three-dimensional finite element analysis (3D finite element analysis) was used to simulate the fixation of the comminuted fracture of the steel plate, to compare and evaluate the mechanical effect of the fixation, and to explore the risk of the fixation of the femoral fracture with oblique plate, and to provide a theoretical basis for clinical treatment. Method: 64 Spiral CT scan normal adult femur, obtain femur DICOM data, introduce DICOM data into Mimics medical modeling software for three-dimensional reconstruction, and establish the model of femoral shaft comminuted fracture; use Pro/E Wildfire 5 software to establish the plate model based on the locking plate of femur, and introduce this model STL file into Mimics, and combine the femur with the femur. The fracture model was performed by simulated internal fixation, and then the plate was placed at different deflection angles. According to the anterior and posterior partial screws, the two groups were divided into two groups, which were the anterior and posterior inclination of the plate. Each group was divided into five subgroups of 2mm, 4mm, 6mm, 8mm, 10mm respectively according to the distance of the distant and proximal screw distance cortex, and 11 groups were added to the normal medium plate. Grid division and assignment were carried out through 3-matic and Mimics respectively, and the load and constraint of simulated 70kg adult bipedal standing were applied to each internal fixation model. The equivalent stress and displacement of the femur and inner plant between the groups were observed. The stress peak value of 1,5,6 nail bone interface increased gradually in the oblique group: (1) the stress concentration of the bone cortex appeared in the 2 groups and the front 4 groups, and the intensity of stress concentration was greater than that of the femoral cortex. In the 6 groups, the stress concentration of the 5,6 nail hole cortex appeared, and was greater than the strength of the femoral cortex; (2) in the 2 groups, the backward 4 groups, and the posterior inclination 6. In the group 1, No. 5 and No. 6, the cortical bone and the 8 groups of the posterior tilt were 5. The cortical bone cortex appeared stress concentration and exceeded the strength of the bone cortex. (3) in each subgroup, the peak stress and strain of the locking plate and screw were located at the nailed plate junction of No. 3 screw and did not exceed the strength of the titanium alloy; (4) (4) in the steel plate forward group, (4) The axial displacement of the broken end of the fracture increased, and (5) the axial displacement decreased and the shear displacement increased as the steel plate tilted. Conclusion: when the proximal end of the locking plate of the femur is placed forward, when the distance of the screw is smaller than 6mm, the two most distal screw will be in the process of weight negative. When the distance of the screw distance to the bone is less than 4mm, the bone cortex of the two distal screws and the proximal screws may have fatigue fracture when the distance of the screw is less than the cortical bone, which leads to the failure of the internal fixation of the distal end screw and the proximal end of the locking plate when the screw is placed in the bone cortex. When the surface is less than 8mm, the most distal two screws will lose the holding force due to the bone destruction near the screw during the loading process. When the screw is less than 6 mm, the bone cortex of the distal two screws and the proximal screws may have fatigue fracture, which will lead to the failure of the internal fixation of the distal end screw and the plate before the screw. After placing weight, the axial stability of fracture end will decrease after loading, and the weight of the plate behind the plate will lead to the reduction of the fracture end of the fracture to the stability, which is also not conducive to the fracture healing. The above conclusion suggests that we should use the MIPO technique to deal with the broken bone fracture in the femoral shaft. The plate should be placed in parallel with the long shaft of the femoral shaft to obtain the best fixation effect. When the steel plate is placed during the operation, the proximal end of the plate should be more than 6mm when the proximal end of the plate is tilted forward, and the distance to the proximal end screw should be greater than 8mm when the proximal end of the plate is tilted. Otherwise, the distal end screw of the plate should be greater than that of the bone. In the post recovery period, there is a risk of fracture around the plate. If the plate is placed after the plate is placed, the position of the steel plate can not be repeatedly adjusted to avoid excessive damage to the soft tissue, damage the fractured end blood transport and avoid unnecessary iatrogenic radiation damage. When the steel plate is tilted, the fracture ends micro The movement is greater than that of the plate placed parallel to the longitudinal axis of the femur, so the lower weight bearing should be avoided before fracture healing to avoid nonunion.
【学位授予单位】：天津医科大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.3
【参考文献】
相关期刊论文 前2条
1 吴新宝;孙林;王满宜;蒋协远;武勇;;股骨干骨折合并同侧隐性股骨颈骨折的诊治分析[J];中华外科杂志;2006年08期
2 徐遄,吴勇,贾克斌,陈刚,李会通;数字医学影像与通信的重要标准——DICOM标准[J];中国医学影像技术;2002年09期
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