摘要
背景:股骨颈骨折后缺血性坏死及骨不愈合的发生率与内固定器械的生物力学性能密切相关,压缩应力可促进骨折愈合,张应力可推迟骨折愈合,剪切应力可阻止骨折愈合。如何消除剪切应力,扩大压缩应力具有重要的理论和临床意义。目的:比较两种构型空心加压螺钉固定头颈型股骨颈骨折的股骨标本的生物力学特征,为临床治疗股骨颈骨折提供生物力学依据。设计:观察对比实验。单位:解放军第二五一医院骨科,河北医科大学第三医院骨科。对象:实验于2002-11/2003-03在河北骨科研究所完成。选取河北医科大学解剖教研室提供的骨密度值相近的标本5具,男性4具,女性1具,经X射线摄片证实无风湿、结核、肿瘤、骨折、畸形变异。方法:将10根股骨随机分成倒等腰三角形组和正等腰三角形组,每组5根。倒、正等腰三角形构型的三枚空心加压螺钉固定头颈型股骨颈骨折的股骨标本,用生物力学机(长春市实验机研究所产CSS-44020生物力学仪,河北骨科研究所提供)测试、比较两种空间构型抗压、抗扭性能及最大垂直载荷。主要观察指标:①抗压实验中在600N和750N时股骨头下沉的位移。②抗扭转实验中扭转2°和4°时的力矩。③最大垂直负荷实验中至内固定失败的负荷。结果:①600N和750N垂直载负下,倒等腰三角形组股骨头下沉位移小于正等腰三角形组[(0.933±0.135),(1.556±0.235)mm;(1.310±0.217),(1.975±0.250)mm,P均<0.05]。②倒等腰三角形组和正等腰三角形组在扭转2°和4°时所需力矩相近,差异无显著性[(3.148±0.765),(2.847±1.130)N·m;(6.658±2.021),(5.392±1.601)N·m,P均>0.05]。③倒等腰三角形组最大垂直载荷大于正等腰三角形组[(2069.97±200.864),(1614.57±80.567)N,P<0.05]。结论:对头颈型股骨颈骨折,应用倒等腰三角形构型的空心加压螺钉比正等腰三角形构型的空心加压螺钉固定股骨标本,可获得更好的抗压和体现其最大垂直载荷性能的生物力学效果。
BACKGROUND: After femoral neck fracture, incidences of ischemic necrosis and bone non-healing are closely related to biomechanical characteristics of internal fixation devices. Compression stress can improve fracture healing, tension force can delay fracture healing, and shear stress can inhibit fracture healing. How to relieve shear stress and expand compression stress is of significance for theories and clinical applications.
OBJEETIVE: To compare the biomechanical characteristics of the two geometric configurations of three cannulated compression screws in the fixation for femoral neck fracture and to provide a theoretical foundation in the treatment of femoral neck fracture. DESIGN : Observational contrast study
SETTIHNG: Department of Orthopaedics, the 251 Hospital of Chinese PLA; Department of Orthopaedics, the Third Hospital, Hebei Medical University.
PARTICIPANTS: The experiment was carried out in the Hebei Orthopaedic Institute from November 2002 to March 2003. Five cadavers including 4 males and 1 female with similar bone mineral density (BMD) were provided by Department of Anatomy, Hebei Medical University. X-ray photographs proved that all the cadavers did not have rheumatism, tuberculosis, tumor, fracture or deformity.
METHODS: Ten femurs were randomly divided into inverted and upright isosceles triangle with 5 in each group. Femur samples with femoral neck fracture were fixed with three cannulated screws and measured with the biomechanical machine (CSS-44020, made in Changchun Experimental Researching Institute, provided by Hebei Orthopaedics Institute). The compression strength, torsibility and the maximal vertical loading were compared between the two configurations of screws.
MAIN OUTCOME MEASURES: (1) Displacement of femoral head at 600 N and 750 N during torsibility test; (2) torque-moment at 2° and 4° during torsibility test; (3) load during maximal vertical loading test.
RESULTS: (1) The femoral head displacement of the inverted isosceles triangle group was shorter than that of the upright isosceles triangle group [(0.933±0.135), (1.556±0.235) mm; (1.310±0.217), (1.975±0.250) mm, P 〈 0.05] at the 600 N and 750 N vertical loading. (2) The torque-moment of the inverted isosceles triangle was similar to that of upright isosceles triangle group at 2° and 4° torsibility [(3.148±0.765), (2.847±1.130) N-m; (6.658±2.021), (5.392±1.601) N o m] and there was no significant difference between them (P 〉 0.05). (3)The maximal vertical loading of inverted isosceles triangle group was higher than that of upright isosceles triangle group [(2 069.97±200.864), (1 614.57±80.567) N, P 〈 0.05].
CONCLUSION : The effect of three cannulated compression screws configured as an inverted isosceles triangle on the treatment of femoral neck fracture is superior to that of three cannulated compression screws as an upright isosceles triangle.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2007年第25期5039-5041,共3页
Journal of Clinical Rehabilitative Tissue Engineering Research