Fourth generation head fracture in ceramic-on-polyethylene bearing after hip revision surgery: a case report.

Fourth generation ceramic bearings (BIOLOX delta, CeramTec AG; Phlochingen, Germany) were developed to reduce wear debris and improve fracture resistance. A case of a fourth generation head fracture in ceramic-on-polyethylene (COP) coupling after hip revision surgery is reported. A 58-year-old man was admitted to our department for increasing hip pain following a direct trauma which occurred during skiing activity 4 months before. Six years earlier, he had undergone a right cementless revision surgery with a 36-mm BIOLOX delta femoral head on polyethylene liner for metallosis and foreign body reaction after primary total hip replacement for hip osteoarthritis. At admission, radiological evaluation revealed a fracture of ceramic femoral head requiring a new revision surgery. Extensive synovectomy, lavage and capsulectomy were performed. Both acetabular cup and femoral stem were well fixed with no damage of trunnion, and therefore they were retained. A 36-mm internal diameter polyethylene acetabular liner was inserted along a 36-mm BIOLOX delta head with a BioBall adapter XL. The postoperative course was uncomplicated. At 1-year follow-up, the patient had a complete functional recovery. To our knowledge, BIOLOX delta ceramic femoral head fracture after COP hip revision surgery has not been previously reported.

The biocompatibility of bone cements: progress in methodological approach.

The ideal bone graft substitute should have certain properties and there are many studies dealing with mixture of polymethylmetacrilate (PMMA) and ß-tricalciumphospate (ß-TCP) presenting the best characteristics of both. Scanning Electron Microscopy (SEM), for ultra-structural data, resulted a very reliable in vivo model to better understand the bioactivity of a cement and to properly evaluate its suitability for a particular purpose. The present study aims to further improve the knowledge on osteointegration development, using both parameters obtained with the Environmental Scanning Electron Microscopy (ESEM) and focused histological examination. Two hybrid bone graft substitute were designed among ceramic and polymer-based bone graft substitutes. Based on ß-TCP granules sizes, they were created with theoretical different osteoconductive properties. An acrylic standard cement was chosen as control. Cements were implanted in twelve New Zealand White (NZW) rabbits, which were sacrificed at 1, 2, 3, 6, 9 and 12 months after cement implantation. Histological samples were prepared with an infiltration process of LR white resin and then specimens were studied by X-rays, histology and Environmental Scanning Electron Microscopy (ESEM). Comparing the resulting data, it was possible to follow osteointegration's various developments resulting from different sizes of ß-TCP granules. In this paper, we show that this evaluation process, together with ESEM, provides further important information that allows to follow any osteointegration at every stage of develop.