Radiostereometric analysis study of @entity11608 compared with XXXX acetabular cups and highly cross-linked compared with conventional liners in young @entity1 undergoing total hip replacement.

@entity691 @entity1 @entity571 @entity702 @entity11608
BACKGROUND: Radiostereometric analysis provides highly precise measurements of component micromotion relative to the bone that is otherwise undetectable by routine radiographs. This study compared, at a minimum of five years following surgery, the micromotion of @entity11608 and @entity702 acetabular cups and femoral head penetration in highly cross-linked @entity691 liners and conventional (ultra-high molecular weight @entity691 ) liners in active @entity1 who had undergone total hip replacement. METHODS: This institutional review board-approved prospective, randomized, blinded study involved forty-six @entity1 . @entity1 were randomized into one of four cohorts according to both acetabular cup and @entity691 liner. @entity1 received either a cementless cup with a @entity702 mesh surface or a @entity11608 trabecular surface and either a highly cross-linked @entity691 liner or an ultra-high molecular weight @entity691 liner. Radiostereometric analysis examinations and Short Form-36 Physical Component Summary, Western Ontario and McMaster Universities @entity571 Index (WOMAC), University of California Los Angeles (UCLA) activity, and Harris hip scores were obtained preoperatively, postoperatively, at six months, and annually thereafter. RESULTS: All @entity1 had significant improvement (p < 0.05) in Short Form-36 Physical Component Summary, WOMAC, UCLA activity, and Harris hip scores postoperatively. On radiostereometric analysis examination, highly cross-linked @entity691 liners showed significantly less median femoral head penetration at five years (p < 0.05). Steady-state wear rates from one year to five years were 0.04 mm per year for ultra-high molecular weight @entity691 liners and 0.004 mm per year for highly cross-linked @entity691 liners. At the five-year follow-up, the median migration (and standard error) was 0.05    0.20 mm proximally for @entity702 cups and 0.21    0.05 mm for @entity11608 cups. CONCLUSIONS: In this young population who had undergone total hip replacement, radiostereometric analysis showed significantly less femoral head penetration in the highly cross-linked @entity691 liners compared with that in the conventional ultra-high molecular weight @entity691 liners. Penetration rates were one order of magnitude less in highly cross-linked @entity691 liners compared with ultra-high molecular weight @entity691 liners. There was no significant difference in proximal migration between the @entity11608 and @entity702 acetabular cups through the five-year follow-up (p > 0.19).
