A comparative study of uncemented tibial components.
The effect of tibial component stem and post design on load distribution and on displacements at the component-bone interface was investigated. Four different configurations were tested with a flat component used as a control. Loading conditions included vertical central, vertical offset (eg, varus/valgus), shear and torque. Both artificial and cadaveric bones were used in the study. Pressure-sensitive film was used to obtain pressure patterns at the interface. Image processing was then used to quantify the load distribution. For shear and torque, relative motion was seen as a smeared pressure pattern. This was calibrated in terms of microns of displacement as a function of image density. The central stemmed and bladed designs performed better than short-pegged designs, in resistance to offset loading. In shear and torque, short pegs close to the component periphery, or a central stem with blades, produced the least interface displacement. The application of this work to the design of components for both press-fit and cemented application is discussed.
Walker
P S
PS
Institute of Orthopaedics, Department of Biomedical Engineering, Middlesex, United Kingdom.
Hsu
H P
HP
Zimmerman
R A
RA
D002484:Cementation; D006801:Humans; D066298:In Vitro Techniques; D007719:Knee Joint / Q000502:physiology; D007720:Knee Prosthesis; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013977:Tibia