Abstract
1. A general picture of the histological state of the bone-cement junction, up to seven years after implantation, is presented as a result of the study of twenty-three human specimens.
2. The transmission of load from cement to bone occurs at isolated points through the medium of newly formed fibrocartilage.
3. It is clear that this fibrocartilage has been produced in response to mechanical pressure on fibrous tissue which has undergone compression between cement and underlying bone.
4. Direct contact exists between the surface of the cement and the newly formed fibrocartilage at these sites of load transmission.
5. Load-bearing fibrocartilage frequently shows areas of ossification extending into it from the underlying bone.
6. Where soft tissues in contact with cement are too thick or too delicate for load transmission a thin layer of giant-cell cytoplasm coats the cement surface.
7. No collections of giant cells to form granulomatous or caseating areas have been seen.
8. Fat storage, indicating the absence of chemical irritation, can occur within ten microns of the cement surface.
