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Friday, October 8, 2010, 8:00-8:30Session A10: Bearings and TribologyComparison of the Stem Geometries of Lateral Flare Stems Using 3D CADand FEA -Stems Are Alternative Load Interface Between Pelvis andFemoral Cortex-*Hirotaka Iguchi - Nagoya City University - Nagoya, JapanNobuyuki Watanabe - Nagoya City University - Nagoya city, JapanNobuhiko Tanaka - Nagoya City University - Nagoya, JapanSinn'ichi Hasegawa - Nagoya City University - Nagoya, JapanSatona Murakami - Nagoya City University - Nagoya City, JapanKaneaki Tawada - Department of Arthroplastic Medicine, Nagoya City University - Nagoya,JapanMasahito Yoshida - Nagoya city university - Nagoya, JapanGen Kuroyanagi - Nagoya East Medical Center - Nagoya, JapanAtsunori Murase - Naogya East Medical Center - Nagoya, JapanTakanobu Otsuka - Nagoya city university - Nagoya, Japan*Email: iguchi@med.nagoya-cu.ac.jpOne of the ironies in modern technology for arthroplasty is the stress shielding in cementlessstems. The aim of the development of cementless stems had been reduction of stress shieldingwhich cement stems are not free from. In healthy femur, trabecula start form the femoral headand reach at both medial and lateral cortex in rather narrow area around lesser trochanter. So theload from the femoral head is transferred at the level on both medial and lateral side. Cementstems should have binding to the cortical bone from collar to the tip of the stem where thecement interlays, and then the load is transferred gradually from the tip to the collar, whichmeans mild stress shielding. When distal bonding is removed, the load could be transferred asnormal femur. This should have been one of the biggest requests for cementless stem. But inrealty many cementless stems have difficulty to obtain a load transfer at the level like normalfemur.Since 1990, we have been mainly using lateral flare stems to obtain contact on both medial andlateral side at proximal level. In the present study, different types and length of the designs werecompared by 3-Dimensional fill, 3-Dimensional fit and Finite Element Analysis.Materials and MethodsStems from DJO: Revelation Standard, Revelation Short, and Linear stems were inserted intopatients’ canal geometries. Three-D fill and 3-D fit which were reported ISTA2009 and stresstransfer were observed by FEA.ResultsThe closest fit and fill were observed Revelation Short and Revelation Standard then Linear.The most proximal load transfer was observed Revelation Short, followed by RevelationStandard then Linear.file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]