Transient viscoelastic lubrication analyses of UHMWPE hip replacements

The viscoelasticity of the UHMWPE liner may play an important role in the lubrication performance of soft artificial hip joints. All the previous lubrication analyses for UHMWPE hip implants assumed that the UHMWPE liner was linear elastic. In order to investigate the influence of viscoelasticity of the UHMWPE liner, a transient viscoelastic lubrication model was developed. The results showed that the viscoelasticity played a significant role in the lubrication performance of UHMWPE hip implants. Moreover, the retardation time and the ratio of loss and storage modulus of the UHMWPE liner had important effects on the lubrication performance of hip implants. These findings provide new insights into the lubrication mechanisms of UHMWPE artificial hip joints.