螺钉间夹角对桡骨远端不稳定骨折接骨板应力影响仿真研究

Simulation study on influence of screws angle on stress of bone plate of distal radius unstable fracture

目的比较4种螺钉间夹角排布对治疗桡骨远端不稳定骨折的术后掌侧接骨板应力分布情况,并找出最优固定角度。方法选取1例健康男性志愿者,对其左手桡骨分别建立含骨折断面和骨痂的桡骨远端不稳定骨折的三维有限元模型。掌侧锁定钢板远端螺钉间夹角分别采用0°、5°、10°、15°。选择竖直提起重物情况作为生理载荷和约束条件,在竖直方向施加100N的载荷,模拟手臂提起重物的情况,并计算分析出4种不同螺钉排布角度情况的应力分布。通过比较4种排布方式,选择出其中应力最小的排列方式。结果螺钉间夹角0°~15°时最大应力分别为580.06MPa、493.13MPa、594.38MPa和604.20MPa。在螺钉间夹角5°的情况下竖直提起重物,掌侧锁定钢板上的最大应力小于其他螺钉间夹角排列方式。结论增加远端头部螺钉夹角角度确实能降低接骨板的局部应力。采用螺钉间夹角5°的排列方式可以有效地防止掌侧锁定接骨板应力集中,提高掌侧锁定接骨板使用寿命。

Objective To compare the stress distribution of volar plate after treatment of unstable distal radius fractures with 4 kinds of screws angle,and find the best adapted angle.Methods A 30-year-old male healthy volunteer was selected to establish three-dimensional finite element models of the left hand unstable distal radius fracture in fracture section and callus, respectively.The angle between distal locking screws of volar locking plates was set at 0°,5°,10° and 15°,respectively.The vertical lifting heavy load was set as physiological load and constraint conditions.The load of 100 N in vertical direction was applied and the weight lifting condition of the arm was simulated.The stress distributions of 4 different screw angles were calculated and analyzed.Compared the stresses at 4 angles,the least stress distribution was selected.Results The maximum stress at 0°- 15° angles were 580.06 MPa,493.13 MPa,594.38 MPa and 604.20 MPa,respectively.When the weight was lifted vertically at 5°,the maximum stress on locking plate was smaller than that at other stress angles.Conclusion It is demonstrated that increasing the distal screws angle could reduce the stress of bone locking plate effectively.At screw angle of 5°,the stress concentration of volar locking plate is effectively prevented,and the service life of volar locking plate could be extended.