[Cause of micromotion in distal femoral prosthesis].
To investigate possible causes of micromotion in distal femoral prosthesis.



Based on the assumption that the femur and prosthesis were considered as concentric cylinders with completely bonded interface, a theoretical model simulating the interfacial stress transfer was established. The distributions of the interfacial shear and radial stresses with the changing of z were obtained through mathematics and mechanics deducing.



The maximum interfacial shear stress occurred at the position of z=0, namely, the cross section of the femur neck. The interfacial shear stress sharply decreased with the increasing of z and came to nearly zero at the range of z> 0.1 m. While the interfacial radial stress increased with the increasing of z,at the range of z >0.05 m it was constant and reached the maximum.



The micromotion in distal prosthesis is caused by the interfacial radial stress.
Dong
Wen-wei
WW
The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China.
Yu
Xue-zhong
XZ
Guo
Yi-mu
YM
D001696:Biomechanical Phenomena; D005269:Femur / Q000033:anatomy & histology / Q000503:physiopathology* / Q000601:surgery; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007593:Joint Instability / Q000209:etiology* / Q000503:physiopathology; D008962:Models, Theoretical; D009038:Motion; D011474:Prosthesis Design; D033081:Shear Strength; D013314:Stress, Mechanical