| 摘要 |
The present design attempts to overcome some of the problems associated with existing bearing components used in total joint replacement procedures such as the accetabular cup in the total hip replacement and the bearing component in the total knee replacement. It addresses the mechanisms of load transfer and wear between the articulating surfaces of the prostheses and the bearing component by mimicking as closes as technologically possible the structural function, surface stiffness and properties of an intact articulating surfaces of a healthy joint, to prevent loosening of the prosthetic component and reduce wear of the articulating surfaces. The proposed design overcomes the problem associated with wear by utilising an intermediate bearing component with sandwich structure in which the bearing surfaces are comprised high surface stiffness to overcome the problems associated with wear while the inner core layer of the sandwich is formed of soft material to dampen the dynamic shock loads caused at the joint by every day human activity. With reference to Figure 1, in one embodiment, the proposed intermediate bearing component (10) is comprised of a first layer (11) and second layer (13) which define the outer surfaces of the said intermediate bearing-component (10) with elastic moduli and hardness E1, E2 and H1 and H2 respectively. Inner third layer (12) having elastic modulus and hardness E3 and H3 is sandwiched between the two layers (11 and 13) and bonded thereto at the inner surfaces (18 and 19) of the said layers (11 and 13) to form a layered sandwich structure such that E3 < E1 and E2, and H3 > H1 and H2. The said inner surfaces may be provided with shear keys (20 and 21) and/or have micro porous structure to provide mechanical key between the said surfaces and the inner core (12). |
