Wear plays a key role in the clinical outcome of total hip replacements (THR). In addition, increased frictional moment can stress the implant interfaces which may lead to high torsional loadings in the intermodular taper junction (fretting) and cup loosening and to the development of noise (squeaking). Against the background of larger head diameters (increased range of motion and decreased risk of dislocation), the friction induced by the joint articulation is of particular interest. As of now, the investigation of friction with the use of relevant joint kinematics and loadings are limited to numerical studies. Experimental approaches use simplified models which do not take into consideration complex activities. Thus, with the aim of this study is the identification of articular frictional moments that consider critical A standard hip simulator (Minibionix 852 with 4 DOF Hip setup, MTS, Eden Prairie, USA) was modified in order to allow for high-precision friction measurements during head-insert articulation in all 6 DOF (MC2.5D-500, AMTI, Boston, USA). Disturbing systemic effects have been minimized by using quasi frictionless aerostatic lateral force compensation (Eitzenberger, Wessobrunn, Germany) and cross talk compensation. Beside the standard protocoll for Introduction
Materials and Methods