IN-VITRO ANALYSIS OF PERIACETABULAR DEFORMATIONS IN METAL-BACKED ACETABULAR COMPONENTS

Purpose of the study The purpose of this study was to find a biomechan ical explanation for a clinical failure of metal backed acetabular com ponents. Periacetabular deformations were measured on fresh cadaver bo nes equipped with strain-gauge rosettes. Material and methods Two skel etons, including pelvic bone, the two last lumbar vertebrae, and both femurs were maintained in unipodal equilibrium using metallic cables f or muscle simulation. Loads were applied up to 700 N the approximating average body weight. A comparative study of periacetabular deformatio ns was performed: right sides of each pelvic bone were implanted with conventional cemented implants, and left sides with metal backed cemen ted implants of same diameter and size. Results Significant difference s were noted: whereas no modification was brought by implantation of c onventional cemented sockets, periacetabular deformations were reduced and smoothed after implantation of cemented metal backed implants. Su ch results are in agreement with recently published data obtained, usi ng the finite element analysis method. Discussion A study of pelvic ri ng and acetabular walls displacement was performed, but the authors co uldn't find any clinical relevance to this biomechanical study.