Figure 1. Acetabular cup with (a) no pits (b) 10 pits, and a schematic of micro-pits at (c) point 0 (d) point 3.5 from the centre

From

Effect of Surface Modification of Acetabular Cup with Embedded Micro-Pits on Friction Properties

S. Syahrullail, N. Sapawe, M.D. Razak, Y. Azli

American Journal of Mechanical Engineering. 2014, 2(5), 125-129 doi:10.12691/ajme-2-5-1