Development And Biomechanical Study Of Distal Femoral Sub-Condyle Plate

Objective: An anatomical distal femoral sub-condyle plate is developed for treating the fracture of distal femoral shaft, and explored whether it can effectively achieve stiffness of fracture site and minimize the knee intervention at the same time.Methods: The anatomical distal femoral sub-condyle plate (produced by Xiemen Double Engine Medical Material Co.Ltd.) was developed according to the research of the anatomy of lateralis distal femur. A biomechanical study was conducted to compared its stability with condyle plate: six matched pairs of adult human cadaveric femurs without trauma, tumor, deformity and degeneration disease were collected. The size of each specimen was not significantly different. The left and right femur of the same cadaver was paired with left one as study group and right one as control group. Each specimen was created a transverse fracture of distal femoral shaft with fretsaw at 5cm above the femoral condyle.Sub-condyle plate was fixed for the study group while condyle plate was fixed for the control group. Four screws were fixed proximal and distal to the fracture site separately. Axial compression, three-point bending and torsion test were carried out on the Material Test System (BOSE). Strength and displacement were collected automatically and analyzed by Paired t-test through SPSS16.0 to compared the stiffness of 2 groups.Results: After fixation, the axial stiffness of the sub-condyle plate group and the condyle plate group was 363.36 and 362.53 seperately (t=0.135,P=0.898>0.05).The three-point bending stiffness was 229.51 and 237.56 at sagittal view (t=-0.778 , P=0.472> 0.05), 195.52 and 188.37 at coronal view (t=0.336,P=0.751>0.05) separately. The torsion stiffness was 7.52 and 7.94 seperately (t=-1.491,P=0.196>0.05). No significant difference of the biomechanical property was observed between the sub-condyle plate group and the condyle plate group .Conclusions: The novel anatomical distal femoral sub-condyle plate is a plate that can provide sufficient stability for the fracture of distal femoral shaft and minimize the intervention of knee joint at the same time.