内侧柱支撑重建在肱骨近端骨折稳定性中的生物力学研究

Biomechanical study of medial column support reconstruction on the stability of proximal humeral fractures

目的探讨肱骨近端内侧柱重建以及不同重建方式对肱骨近端骨折稳定性的影响。方法取其肱骨近端标本32根,腓骨标本16根,随机分为4组,每组8个标本。A组在肱骨近端放置PHILOS钢板,并经钢板置入2枚MSS钉;B组在肱骨近端缺损区域髓腔内放置修整后腓骨行植骨支撑以重建内侧柱,外侧放置PHILOS钢板固定;C组在肱骨内侧柱缺损区域髓腔内放置修整后腓骨行植骨支撑,外侧放置PHILOS钢板固定,并经钢板置入2枚MSS钉;D组复位肱骨近端,仅放置PHILOS钢板固定系统。比较4组轴向压缩试验与剪切力试验的最大载荷、抗压刚度,比较4组失效载荷。结果4组均顺利完成试验,C组轴向压缩试验、剪切力压缩试验中的最大载荷、抗压刚度以及失效载荷较其他3组高,D组轴向压缩试验、剪切力压缩试验中的最大载荷、抗压刚度以及失效载荷较其他3组低,差异有统计学意义(P<0.05)。结论肱骨近端内侧柱的有效解剖重建,可明显提高其抗轴向压缩及抗剪切力,采用缺损区腓骨植骨支撑联合经PHILOS钢板置入2枚MSS钉具有最佳的生物力学性能,可提高肱骨近端骨折内固定术后力学稳定性。

Objective To explore the reconstruction of the medial proximal humerus column and the influence of different reconstruction methods on the stability of proximal humeral fractures.Methods Thirty-two proximal humeral specimens and16 fibular specimens were collected and randomly divided into 4 groups with 8 specimens in each group.In group A,PHILOS plates were placed on the proximal humerus and 2 MSS nails were inserted through the plates.In group B,the repaired fibula was placed in the medullary cavity of the proximal humerus defect area for bone graft support to reconstruct the medial column,and PHILOS plate was placed externally for fixation.In group C,the repaired fibula was placed in the medullary cavity of the medial column defect area for bone graft support,PHILOS plate was placed externally for fixation,and 2 MSS nails were placed through the plate.In group D,the proximal humerus was reduced and only the PHILOS plate fixation system was placed.To place the 4 groups of specimens in the electronic universal biomechanics testing machine and the compressive stiffness test,shear compression test and model failure test were performed.The maximum load and compressive stiffness of the 4 groups of axial compression test and shear test,were compared and the 4 groups of failure loads were compared.Results All 4 groups successfully completed the test,and the maximum load,compressive stiffness and failure load in the axial compression test and shear compression test of group C were higher than those of the other 3 groups.The maximum load,compressive stiffness and failure load in the axial compression test and shear compression test of group D were lower than those of the other three groups,and the differences were statistically significant(P<0.05).Conclusion Effective anatomical reconstruction of the proximal medial column of humerus can significantly improve its resistance to axial compression and shear force.The use of fibula bone graft support combination in the defect area and 2 MSS nails inserted through PHILOS plate have the best biomechanical properties,which can improve the mechanical stability after internal fixation of proximal humeral fractures.