A PROSPECTIVE-STUDY OF THE MIGRATION OF 2 ACETABULAR COMPONENTS - PCAVERSUS RM CUPS

Fifty-nine PCA cups and 61 hydroxyapatite-coated RM cups were included in a prospective randomised study with a mean follow up of 5.2 years. Clinical evaluation revealed better results with the RM cup. Radiolog ical criteria of loosening could be applied only with considerable res trictions as different parameters were assessed: progressively loosene d beads in PCA cups and faded contour in RM cups. Migration was measur ed by a computer assisted method (EBRA). PCA cups showed significantly more longitudinal migration 2 years after operation and subsequently. High migration values correlated with a limp. Loosening as defined by migration was of clinical relevance, could be measured early and pred icted the survival rate.