斜置锁定钢板对股骨干骨折内固定的生物力学影响

BIOMECHANICAL IMPACT OF OBLIQUE LOCKING PLATE ON FIXATION OF FEMORAL SHAFT FRACTURES

目的探讨斜置锁定钢板对股骨干骨折内固定的生物力学影响。方法选取40根与人体股骨力学性质类似的仿制人工股骨模型,随机分成A、B、C、D 4组,每组10根,在股骨小粗隆下15 cm和17 cm处横行截骨制备股骨中段粉碎性骨折模型,均用12孔锁定钢板和皮质骨螺钉固定。A组钢板放置在股骨正中纵轴线上,B、C、D组钢板分别放置于5、10、15°夹角的轴线上。测量内固定后4组在轴向压缩、三点折弯、扭转试验中骨折块内外两侧的应变。结果随着压缩载荷和弯曲载荷不断增加,各组内骨折块内外侧应变值也不断增加,比较差异均有统计学意义(P<0.05);但各压缩载荷和弯曲载荷下骨折块内外两侧的应变值4组间比较差异均无统计学意义(P>0.05)。随着扭矩不断增加,各组内骨折块内外侧应变值也不断增加,比较差异均有统计学意义(P<0.05)。扭矩为10 N·m时,骨折块内外两侧的应变值4组间比较差异均无统计学意义(P>0.05);但扭矩为20、50 N·m时,C、D组骨折块内外侧应变值均显著高于A、B组,D组显著高于C组,差异均有统计学意义(P<0.05),A、B组间差异无统计学意义(P>0.05)。结论在不同应力下,斜置钢板>10°会使骨折应变明显加大。

Objective To investigate the biomechanical influence of the oblique locking plate on the fixation of femoral shaft fracture.Methods Forty imitation artificial femur model with mechanical properties similar to human femur were selected and randomly divided into groups A,B,C,and D,10 in each group;the femur fracture model was made by transverse osteotomy at 15 cm and 17 cm below the lesser trochanter of the femur and fixed with locking plate with 12 holes and cortical bone screws.The plate was placed in the middle of the longitudinal axis of the femur in group A,and was placed at 5,10,and 15° angle axis in groups B,C,and D respectively.The axial compression,three-point bending,torsion tests were carried out to measure the strain.Results With the compressive load and bending load increasing,the medial and lateral strains were significantly increased in each group（P〈0.05）;but no significant difference was found in strains under compressive load and bending load among 4 groups（P〉0.05）.With increasing torque,the strain was significantly increased in each group（P〈0.05）.At 10 N·m torque,there was no significant difference in the strain values among 4 groups（P〉0.05）;the strain value was significantly higher in groups C and D than groups A and B（P〈0.05） and in group D than group C（P〈0.05） at torque of 20 and 50 N·m,but no significant difference was found between groups A and B（P〉0.05）.Conclusion Under different stress,the strain will be significantly increased when the plate is placed at 〉10° angle axis.