The first twenty failed total hip replacements in one hospital population showed infection in twelve (two Charnley and ten McKee-Farrar) and loosening in eight (McKee-Farrar). Acute inflammation was present in all of the infections and ranged from mild to severe. Chronic inflammation was universally seen, more severe in the presence of infection. Intracellular and extracellular metallic debris was seen in all but two cases. Acrylic debris was found extracellularly in all cases and intracellularly in small amounts in three. Debris resembling polyethylene was seen in two patients. It was not possible to determine what part the debris played in inflammation versus infection.