Convened under the auspicious of esteemed endorsers - ISTA

outcome, we commend its use in the immature population of long bone tumour cases.Thursday, October 7, 2010, 9:00-9:50Session A2: Alternate Bearings in THA 2Massive Osteolysis Could Not Expand Along Porous Cup Surface WithAW-Glass Ceramics Bottom Coating: A Case Report*Koji Goto - Kyoto University - Kyoto City, JapanHaruhiko Akiyama - Kyoto University - kyoto city, JapanKeiichi Kawanabe - - ,Kazutaka So - - ,Takashi Nakamura - Kyoto University, Graduate School of Medicine - Kyoto, Japan*Email: k.g.bau@kuhp.kyoto-u.ac.jpOne cementless cup which had porous outer surface with Apatite-Wollastonite glass ceramic(AWGC) coating, was revised 13 years after primary THA because of massive osteolysisexpanded to medial iliac wall along the screws. While many retrieved studies ofhydroxyapatite-coated cup have been reported, there has been no report on the retrieved cupwith AWGC coating. The purpose of this study was to describe this rare case in detail, confirmthe bone ingrowth to the porous cup, and discuss on the effectiveness of porous surface withAWGC coating.CaseThe patient was a 64 old woman and complained of chronic mild pain around her left groinregion. X-ray examination revealed that osteolysis had been expanding around the screws andextended proximally. The revision surgery was performed for the massive osteolysis throughHardinge antero-lateral approach. The retrieved implants included a cementless cup made oftitanium alloy (QPOC cup, Japan Medical Materirals Inc.(JMM) Osaka, Japan), the outersurface of which was plasma-sprayed with titanium for porous formation and coated withAWGC in the deep layer. It was found that the polyethylene liner was destructed partially in thesupero-lateral portion, but the cup was well fixed to the bone. The bone-attached area wasfound to be dispersed over the porous surface of the hemispherical cup. Histologicalexamination revealed that matured bony tissue intruded into the porous surface of the cup, andcontacted to bone directly, which was also demonstrated in the back-scattered electron image. Itwas also demonstrated that there were residual silicon (Si) rich regions on the porous surface bythe SEM-EDX analysis, which indicated that constituents of AWGC still remained on thesurface. On the other hand, the results of elementary analyses in the Si rich regions variedamong the sections, which probably indicated that the extent of degradation and absorption ofAWGC varied among the sections.AWGC was one of the bioactive ceramics and reported to have an ability to bond to boneearlier than hydroxyapatite (HA). In the present case, though massive osteolysis occurred withaggressive wear, it did not expand on the porous surface, and rather progressed along thesmooth surface of the screws. Considering that there are many clinical studies reporting poorclinical results of HA-coated smooth cups, bioactive ceramic coating may function well andfile:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]