Human histology of the bone-porous metal implant interface.

Histological study of the bone-implant interface was performed on two retrieved femurs implanted with porous-surfaced metal arthroplasty components. The first case (87-year-old woman, 40day implant period) revealed limited new bone formation but some biological fixation in the proximal medial and distal lateral regions. The second case 82-year-old man, 6½-month implant period) demonstrated more convincing evidence of bone ingrowth and adaptive bone modeling. In general, the development of biological fixation was less pronounced than observed in animal models, probably as a result of factors such as patient age, disease process, and low activity level.