双钢板治疗肱骨髁间骨折3种内固定方式的载荷-应变与位移

背景：很多临床报道认为＂双钢板＂方法治疗肱骨髁间骨折是较为理想的方法,但对于放置方式一直存在争议。目的：比较肱骨髁间骨折应用双钢板固定时,3种不同放置方式的生物力学特性。方法：18具防腐肱骨标本,制成肱骨远端＂T＂型髁间骨折模型,在髁间骨折线两侧各贴2个（共4个）应变片。随机予以背侧双钢板固定、垂直双钢板固定、平行双钢板固定,在压缩载荷下,对3种内固定方式进行应变、位移、刚度的测试。结果与结论：①从载荷-位移数据中可以看到：当载荷低于500N时,3种内固定方式位移差异无显著性意义;在500N时,平行双钢板压缩位移小于背侧双钢板固定、垂直双钢板固定（P〈0.05）。②3种内固定应变较小的是平行双钢板固定,另两种钢板固定方式应变较大,前者与后两者差异有显著性意义（P〈0.05）。内外髁的应变大于髁间应变,外髁的应变最大。当载荷低于300N时,3种内固定方式的刚度差异无显著性意义。在300~500N外力的载荷下轴向压缩刚度以平行双钢板内固定最高,背侧双钢板和垂直双钢板较低,前者与后两者比较差异有显著性意义（P〈0.05）。由此可见,同等载荷下,平行钢板固定效果最佳,垂直钢板固定和背侧钢板固定之间无差异。

Load-strain-displacement of three patterns of dual-plate fixation for intercondylar fracture of the humerus

BACKGROUND：Dual-plate has been regarded as an ideal clinical therapy for intercondylar fracture of the humerus.However,the placement pattern remains controversial.OBJECTIVE：To compare biomechanical characteristics of three placement patterns of dual-plate internal fixation for intercondylar fracture of the humerus.METHODS：A total of 18 anticorrosive cadaveric adult humerus specimens were used to prepare ＂T＂ style intercondylar fracture of the humerus.Two strain gauges were stuck at each side of the fracture line.The fracture was treated by dorsal-plate,perpendicular-plate,and parallel-plate fixation.Biomechanical tests were performed on these specimens,including strain,displacement,and rigidity.RESULTS AND CONCLUSION：Data of the stress and displacement showed that there was no significant difference in displacement among three different internal fixation methods under stress bellow 500 N.The displacement of parallel-plate group was less than dorsal-plate and perpendicular-plate groups under stress of 500 N（P 0.05）.The strain was significantly less in parallel-plate group compared with dorsal-plate and perpendicular-plate groups（P 0.05）.The strain of internal and external condyle was greater than intercondylar strain,and the strain of external condyle was the largest.There were no significant differences in rigidity among three groups under stress less than 300 N.The axial compressive rigidity was largest in parallel-plate group under stress of 300-500 N compared with the other groups（P 0.05）.Under the same load condition,parallel-plate yielded the best results,and there was no obvious difference between dorsal-plate and perpendicular-plate.