人工股関節摺動面における接触応力解析の個体別手法の開発

概要

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The modern and widely known artificial hip joint developed by John Charnley in the 1970s consisted of three parts, 1. a metallic femoral stem, 2. a UHMWPE acetabular liner, 3. a metallic acetabular socket or bone cement. Acetabular liner has a bearing surface of UHMWPE which has a low coefficient of friction and low wear rate. In the long term, wear particulate dose accumulate and lead to a condition known as osteolysis, which leads to bone loss, joint loosening, discomfort, and ultimately limits the lifespan of the artificial joint. Therefore, the evaluation of the wear on acetabular bearings, which depends directly on contact pressure, is essential to analyze the failure of the acetabular implant, as well as for a better design of artificial joint. The objective of the present study was to develop a method of applying discrete element analysis (DEA) based on rigid-body-spring-model (RBSM) to artificial hip joint, using patient-specific 3D bone model and motion capture data, and to analyze the stress distribution on bearing surface during gait motion. The two peaks in peak stress were observed with a maximum value of 12.3 MPa and the corresponding contact area was 21.8% of total bearing area, and small contact area less than 25% at the edge of the superior bearing surface was observed during gait motion.
日本実験力学会の論文