Effect of the area of paries medialis defect on the stability of fracture ends after percutaneous compression plating for femoral intertrochanteric fracture / 中华创伤骨科杂志

ABSTRACT

Objective To analyze the effect of different areas of paries medialis defect of femoral trochanter on the stability of fracture ends after percutaneous compression plating for femoral intertrochanteric fracture.Methods Thirteen preserved cadaveric specimens of adult femur were used in this experiment.The age of death ranged from 30 to 50 years.Oblique osteotomy was conducted under the same condition using a wire saw to create experimental models of fracture of Evans-Jensen type Ⅳ.The ratios of the area of paries medialis defect to the projected area of lesser trochanter in the specimens 1 to 13 were set respectively as 0,10.0％,14.5％,20.2％,23.4％,30.6％,45.8％,56.8％,76.8％,88.7％,99.8％,121.3％ and 149.4％.All the fractures were fixated by standard percutaneous compression plating.Cyclic load was applied on each specimen using Instron 2000 universal material tester.A vertical load of 600 N was applied for respectively 1,10,100 and 1,000 times to measure the displacements of proximal and distal fracture ends.Results When the ratio of the area of paries medialis defect to the projected area of lesser trochanter was 30.6％,the average displacements of the proximal and distal ends were 0.14 cm and 0.10 cm.When the ratio was 45.8％,the average displacement of the proximal end was 0.53 cm,278.6％ greater than that for 30.6％;the average displacement of the distal end was 0.41 cm,310.0％ greater than that for 30.6％.When the ratio was 149.4％,the average displacement of the proximal end was 0.93 cm,564.3％ greater than that for 30.6％;the average displacement of the distal end was 0.65 cm,550.0％ greater than that for 30.6％.Conclusions When the ratio of the area of paries medialis defect to the projected area of lesser trochanter reaches ＞ 45.8％,the area of paries medialis defect will have a significant effect on the stability of fracture ends after percutaneous compression plating for femoral intertrochanteric fracture.The displacement will increase linearly under the same compression with the increase in defect area.