EBRA IMPROVES THE ACCURACY OF RADIOGRAPHIC ANALYSIS OF ACETABULAR CUPMIGRATION

EBRA (Ein Bild Rontgen Analyse) is a new computerized method measuring migration and wear of the acetabular cup, suggested to improve measur ement accuracy. We evaluated possible errors of measurement and compar ed EBRA with standard methods. 1. We did repeated measurements on a si ngle radiograph using the same reference lines. The reliability of the input procedure with standard measurements was significantly better t han repeated digitization with EBRA. 2. In a more clinical test, a gro up of 10 patients was studied. 5 radiographs were taken of the same pa tient on the same day. EBRA improved the reliability of repeated radio graphic examination significantly for migration measurements in the ve rtical direction. 3. To assess the inter- and intraobserver variations , repeated measurements were performed on the clinical series of pelvi c radiographs of 10 patients. EBRA was significantly better than stand ard methods. With EBRA, errors of wear and migration measurements coul d be reduced, as compared to standard methods, The major improvement w ith EBRA was found for migration measurements in the vertical directio n.