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Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 139 - 139
1 Sep 2012
Topolovec M Milosev I Coer A Bloebaum R
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Background

Wear particles are considered to be the major culprit for the aseptic loosening. Their characterization is thus crucial for the understanding of their bioreactivity and contribution to the development of aseptic loosening.

Methods

Metal wear debris particles were analyzed directly in periprosthetic tissue resins by scanning electron microscopy (SEM) combined with back-scattered electron imaging (BSE) and energy dispersive X-ray spectroscopy (EDS). Four groups of tissue samples retrieved at revision operations of loosened hip implants with different bearing surfaces (metal-on-metal, ceramic-on-polyethylene and metal-on-polyethylene), and different material of the femoral stem (Ti alloy, CoCrMo and polymer combined with stainless steel) were investigated. Tissue samples were first analyzed histologicaly. Sections from the same paraffin blocks were then carbon coated and analyzed using SEM/BSE/EDS method.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 132 - 132
1 Sep 2012
Milosev I Kovac S Trebse R Levasic V Topolovec M Pisot V
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Introduction

Alternative bearings – metal-on-metal and ceramic-on-ceramic bearings have been introduced in the last decade with the aim to diminish wear and, subsequently, aseptic loosening and osteolysis. These bearings were aimed for younger, more active patients. Clinical results which would compare the performance of various alternative and traditional bearings are scarce.

Methods

Between January 2000 and December 2002, we performed 487 total hip replacements in 474 patients using three types of bearings: metal-on-metal (MOM), metal-on-polyethylene (MOP), and ceramic-on-ceramic (COC). All patients received the same type of acetabular cup (Bicon-Plus, Plus Orthopedics) and same type of femoral component (SL-Plus, Plus Orthopedics). We used the hospital computer database for the evaluation of patient data and data on revision operations.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_III | Pages 310 - 311
1 Mar 2004
Trebse R Milosev I Fonda S
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Introduction: Stress shielding has been found to cause cortical thinning and loss of trabecular bone in the proximal femur due to stiff steam and elastic bone. To avoid these problems a prosthesis was developed according to the concept of isoelasticity. Its aim was to ensure the implant and the bone to deform as one unit loading the bone in a more physiological way. Methods: From 1984 Ð1987 we performed 149 total hip replacements using third generation Mathys isoelastic polyacetal stem with stainless-steel heads and polyethylene cementless acetabular cups. Average patient age was 47 years (21–82). Eleven patients (12 hips) has died before revision and fourteen (15 hips) were lost to follow up. Results: Hitherto 69 hips were revised, þve due to infection. The 10 years revision rate for any reason was 68.7%. The remaining 48 patients (53 hips) have been clinically and radiologically assessed or reviewed by a questionnaire. In these patients the average HHS was 80 points. Thirteen among them had failed radiologically, many without a poor subjective result. Conclusions: The performance of this prosthesis was unacceptably poor but nevertheless the concept of isoelasticity should not be completely disregarded. Future trends may reconsider and reintroduce some new materials or implant designs which would be able to achieve the aim of isoelasticity without former problems. Long term total hip loosenings are still all but solved.