Fig. 8.

An energy-dispersive x-ray spectrum (Case 5) reveals the elemental composition of particles rich in chromium (Cr) and consistent with chromium phosphate corrosion product. Traces of cobalt (Co) and titanium (Ti) are also present, the latter suggesting that these particles were generated by corrosion at the junction between the cobalt-chromium modular femoral neck and the titanium alloy stem. The particles (inset) lie in necrotic fibrous tissue of the joint pseudocapsule (backscattered electron micrograph, ×200). O = oxygen, Mg = magnesium, P = phosphorus, S = sulfur, and Ca = calcium.