新型组合式锁定加压钢板治疗股骨干粉碎性骨折的生物力学研究

A new assembly of locking compression plate for treatment of femoral shaft comminuted fracture a biomechanical study

目的 比较新型组合式锁定加压钢板（NALCP）与传统锁定加压钢板（LCP）在股骨干粉碎性骨折内固定术中的生物力学特性. 方法 收集6对（12个）股骨标本,按左右配对随机分为A、B两组,每组6个,制备股骨干楔形骨折模型（AO分型32-C2.1）.A组采用NALCP固定,B组采用LCP固定.对两组钢板进行生物力学性能测试,通过轴向加载和扭转加载试验,分别记录两组骨折块在X、Y、Z轴（X轴为冠状轴,通过股骨内外踝;Z轴为横断面轴,通过股骨髁间窝,与X轴垂直;Y轴为矢状轴,与X、Z轴垂直）上的相对最大位移、钢板的主应变和平均应变;制作出应变分布云图;记录NALCP组轴向加载疲劳试验结果. 结果 轴向加载试验：A组骨折块在X、Y、Z轴上的相对最大位移均小于B组（P＜0.05或0.01）,钢板主应变大于B组（P＜0.01）,钢板平均应变与B组比较差异无统计学意义（P＞0.05）.扭转加载试验：A组骨折块在X、Z轴上的相对最大位移均小于B组（P＜0.01）,Y轴上的相对最大位移两组差异无统计学意义（P＞0.05）;A组钢板主应变大于B组（P＜0.01）,钢板平均应变与B组比较差异无统计学意义（P＞0.05）.两组钢板应变云图分布基本一致.A组通过100万次的轴向循环载荷疲劳测试,NALCP完好,无形变、松动、断裂. 结论 NALCP能够为股骨粉碎性骨折提供坚强的力学稳定性,桥接钢板设计合理,可有效避免应力集中,减少钢板的应力遮挡,易于促进骨愈合.

Objective To compare the biomechanical characteristics of new assembly of locking compression plate （NALCP） and locking compression plate （LCP） in internal fixation of femoral shaft comminuted fractures.Methods The preparation of a femoral shaft wedge fracture model （AO type 32-C2.1）,six pairs of （12） femoral specimens were collected and divided into two groups randomly,with six in each group.The Group A was made up of the new assembly of locking compression plate fixation model （NALCP）,and Group B the locking compression plate fixation model （LCP）.The biomechanical properties of steel plates in two groups were tested by axial loading and torsional loading tests.The relative maximum displacement of fracture blocks in two groups on the X,Y and Z axes （the coronal axis was set as X axis,through the medial and lateral femur;the transverse axis was set as Z axis,through the femoral intercondylar fossa,perpendicular to the X axis;the sagittal axis was set as Y axis,perpendicular to the X and Z axis）,the maximum strain,and the average strain of the steel plate were recorded.Strain distribution nephogram was produced,and the axial loading fatigue test results of Group A were recorded.Results Axial loading test：the relative maximum displacement of fracture in Group A on X,Y and Z axis were smaller than those in Group B （P 〈0.05 or 0.01）;the main strain of Group A was greater than that of Group B （P 〈0.01）;there was no significant difference in the average strain between Group A and Group B （P 〉 0.05）.Torsional loading test：The relative maximum displacement of fracture in Group A on X and Z axis was smaller than that of Group B （P 〈 0.01）;there was no statistically significant difference between the two groups on the Y axis （P 〉 0.05）;the main strain of plate in Group A was greater than that in Group B （P 〈 0.01）;there was no statistically significant difference in the average strain between Group A and Group B （P 〉 0.05）.There was no obvious difference in strain distribution between the two groups.In Group A,the fatigue test of axial cyclic loading was performed for 1 million times,and the NALCP was intact without deformation,loosening,or rupture.Conclusion NALCP can provide strong mechanical stability for comminuted femoral fracture.The design of bridge steel plate is reasonable,which can effectively avoid stress concentration,reduce the stress shielding of steel plate,and facilitate bone healing.