Shock machine for the mechanical behaviour of hip prostheses: a description of performance capabilities

Juliana Uribe (1, 2, 3, 4) , Jean Géringer (1, 2, 3, 4) , Bernard Forest (1, 2, 3, 4)

1 DB2M-ENSMSE - Département Biomécanique et Biomatériaux
2 CIS-ENSMSE - Centre Ingénierie et Santé
3 IFRESIS - Institut Fédératif de Recherche en Sciences et Ingénierie de la Santé
4 LCG-ENSMSE - UMR 5146 - Laboratoire Claude Goux

The aim of this study was to describe the behaviour of a shock machine designed for testing hip prostheses. A microseparation between head and cup occurs inducing a shock of several times the body weight, leading to fracture of ceramic femoral components. Femoral heads and cups of diameter 32 mm manufactured from alumina were tested in dry and wet conditions. Implants were subjected to shocks with a load profile of 9 kN load at 2 Hz and various microseparations. Position is monitored and force is measured with two acquisition systems. The working range and the device capabilities were investigated. Only cups tested in dry conditions failed. Observations by scanning electron microscopy revealed intergranular and transgranular fractures. Two wear stripes were observed on the heads. Three-dimensional roughness of wear stripes was measured. Since experimental results are in good agreement with retrieved femoral heads, the shocks machine reproduces the in vivo degradations.

Mots clés: hip prostheses; shock machine; wear stripe; alumina

Domaines: Génie des procédés; Biomécanique [physics.med-ph]; Biomécanique [physics.med-ph]

Juliana Uribe, Jean Géringer, Bernard Forest. Shock machine for the mechanical behaviour of hip prostheses: a description of performance capabilities. Lubrication Science, 2012, 24 (2), pp.45-60. ⟨10.1002/ls.167⟩. ⟨hal-00682226⟩