Performance analysis of total hip prostheses: some particular metallurgical observations.

Metallurgical observations of phenomena which influence the clinically successful performance of permanent implants and implant materials are reported. The effect of casting voids in cast cobalt chromium femoral stems of total hip replacements is discussed first. Pitting corrosion occurred in a retrieved stainless-steel implant type AISI 316 containing 2.7% Mo. The fractographic pattern of this device retrieved for fatigue failure shows typical characteristics of corrosion-enhanced fatigue.