Bacteriological and histological study of 40 loose cemented hip prostheses.

The causes of the loosening of a hip prosthesis may be inflammatory, mechanical, immunitary or due to detritus. A bacteriological and histological study, in cases where further surgery was needed, may clearly contribute to the aetiopathogenesis of failure. Loose hip prostheses removed at operation were studied from a bacteriological and, in particular, histological point of view. There results were then correlated to clinical, radiographic and laboratory data obtained during follow-up. Inflammation proved to be a constant histological finding. The hyalinosis observed in 22 cases revealed significant analogies with histological pictures of silicotic granuloma, for which an immunitary pathogenesis is the current hypothesis. Thus, it is our belief that this correlation is suggestive of an immunitary based approach in cases where hip prostheses fail due to loosening.