Modelling cementless cup fi xation in total hip arthroplasty (THA) 371
The surface structures of press- t cups (Fig. 12.1) are categorised by
the level of roughness, that is, macrostructure (>2000 µ m), mesostructure
(between 2000 and 100 µ m) and microstructure (<100 µ m). Pore size of the
different structures varies between 100 and 400 µ m. Porosity amounts from
20% up to 70%. In order to obtain a physiological-like force transmission in
the acetabulum, the pole of press- t cups is attened (Morscher and Masar,
1988; Morscher et al ., 1989). Consequently, a lower level of micromotion in
the implant–bone interface at the region around the pole is achieved .
Besides the different methods and levels of surface structuring and sur ...