Eight year results of Charnley arthroplasties of the hip with special reference to the behavior of cement.

Five hundred and forty-seven total hip replacements by the Charnley technique during 1967 and 1968 have been studied for the quality of the late results. The average follow-up was 8.3 years. Mechanical failure at the cement-bone interface occurred in only 2.2% of cases. A search was specially directed towards evidence of incipient pathology at the bone-cement interface in the absence of any suspicion of clinical defect. This was found in 12% of cases but it is emphasized that the criteria were exceptionally rigorous and entirely radiological. Because the cement technology used at that time is now considered unsophisticated, mechanical failure of cement is a preventable condition. A previous report of socket migration in 9.5% of cases is not confirmed by the present survey of a more recent series of cases.