A key factor that may contribute to relative motion (fretting) at modular connections and ultimately to abrasive loss of the passivating oxide layer is angular mismatch between the taper on the male aspect of the connection and the bore on the female aspect. Such a mismatch may result if the tolerances are relatively large, leading to poor mechanical stability of the connection. In this situation, the loads produced during the normal gait cycle may dislodge the interference fit of the modular connection, leading to disruption of the metal surfaces and initiation of the cascade just described