A comparative study of Osteal ® stem subsidence using EBRA-FCA ® method and a specific and original analysis model developed with the Imagika ® software.

The radiological follow-up is an essential element of evaluation of total hip arthroplasty. This is a retrospective study based on 71 THA using a cemented Ceraver-Osteal ® stem. They were systematically associated with RM ® cups in all cases with a ceramic on polyethylene bearing surface. The mean age of patients was 74.4 +/-10.2 years and the mean follow-up was 7.9 +/- 0,9 years. Aetiologies were 61 osteoarthritis, 4 osteonecrosis and 6 femoral neck fractures. The main purpose of this work is to verify if a subsidence of femoral implants and radiological changes can be recognized in a comparable pattern using EBRA-FCA ® method and Imagika ® software. The measured subsidence is 0.05 +/- 0.005 mm / year with EBRA-FCA ® and 0.06 +/- 0.004 mm / year with Imagika ® (p = 0.74). We did not show significant migration whatever the method used. The precision of the Imagika ® method, thanks to the automatic detection of contours and the use of a correction factor, makes it possible to objectify sub- millimeter migrations of femoral stems. The absence of a significant difference between the two methods makes it possible to validate the Imagika ® method.