Effect of slide track shape on the wear of ultra-high molecular weight polyethylene in a pin-on-disk wear simulation of total hip prosthesis.

Prosthetic joints appear to show a strong relationship between the type of relative motion and wear, requiring careful consideration in the design of wear simulators. This relationship was studied with a 12-station pin-on-disk device, specifically adapted for the wear simulation of prosthetic hip joints. Each station had a unique motion, characterized by the so-called slide track, the track of the pin on the disk.

An improved method of computing the wear factor for total hip prostheses involving the variation of relative motion and contact pressure with location on the bearing surface.

A new method of computing the wear factor for total hip prostheses is presented. In the conventional method, only the resultant contact force and the track drawn by the point of its application are considered so that the product of the instantaneous force and sliding increment is integrated over one motion cycle. In the present, improved, method the contact pressure distribution is discretized by a large number of smaller normal forces, and the contribution of each is summed.

Force track analysis of contemporary hip simulators.

In an earlier paper, the authors presented the first verified method of computation of slide tracks in the relative motion between femoral head and acetabular cup of total hip prostheses. The method was applied for gait and for two hip simulator designs, and in a subsequent paper, for another eight designs. In the present paper, the track drawn by the resultant contact force, the so-called force track, was studied in depth.

Effect of extent of motion and type of load on the wear of polyethylene in a biaxial hip simulator.

The most commonly used wear test device for prosthetic hip joints is the so-called biaxial rocking motion (BRM) design. The design has been criticized for its excessive sliding distance per cycle. The design was modified so that the extent of motion was reduced from 46 to 23 degrees, and comparative tests were run with the use of 1-kN static load.

Wear of conventional and cross-linked ultra-high-molecular-weight polyethylene acetabular cups against polished and roughened CoCr femoral heads in a biaxial hip simulator.

The wear of acetabular cups made from conventional gamma-sterilized, and electron-beam cross-linked ultra-high-molecular-weight polyethylene was studied with a biaxial hip wear simulator. The femoral heads were either polished or roughened so that they represented the type of roughening and the value of surface roughness (R(a) = 0.14-0.