The correlation between the roentgenographic appearance and operative findings at the bone-cement junction of the socket in Charnley low friction arthroplasties.

In a series of 200 Charnley low friction arthroplasties revised for various reasons, the preoperative anteroposterior roentgenograms were categorized in terms of demarcation at the bone-cement interface of the socket and compared with the operative findings of movement at the bone-cement junction. All sockets showing no demarcation were found to be fixed soundly. Seven percent of the sockets showing demarcation of the outer one-third only were loose, and when two-thirds of the sockets were demarcated, 71% were loose. Ninety-four percent of the sockets with complete demarcation and all sockets that had migrated were found to be loose at revision. There is a definite correlation between roentgenographic demarcation and socket loosening. The more extensive the demarcation, the more likely it is that the socket is loose. Radiographic demarcation of the cemented socket is a prognostic sign for eventual failure.