ANALYSIS OF THE ACETABULAR MIGRATION PROFILE IN RHEUMATOID-ARTHRITIS COMPARED WITH CEMENTLESS ACETABULAR REVISION

In a retrospective analysis the migration profile of 73 cementless tot al hip implants (Zweymuller Alloclassic) in 54 patients with rheumatoi d arthritis were compared with the results of 58 implants of the same design in 50 patients undergoing cementless revision after loosening o f an Endler cup. 258 conventional radiographs of the rheumatoid patien ts and 164 radiographs of the revision group were digitized. The migra tion analysis was performed using a modified Dickob's technique that a llows for correction of different X-ray magnifications as well as hori zontal and vertical tilting of the pelvis. The analysis of migration e xceeded 2 mm in eight rheumatoid patients. In three of them clinical l oosening of the acetabular cup was obvious. In the group of patients a fter cup revision a significantly higher amount of cranial migration w as detected compared with the rheumatoid patients. This phenomenon cou ld be explained by the destruction of the weight-bearing cranial aceta bular sclerosis after reaming.