1. H. Oonishi Memorial Joint Replacement Institute; Tominaga Hospital; Osaka Japan
2. Research Department; KYOCERA Medical Corporation; 3-3-31 Miyaha, Yodogawa-ku Osaka 532-0003 Japan
3. Department of Materials Engineering; School of Engineering; The University of Tokyo; Tokyo Japan
4. Division of Science for Joint Reconstruction; School of Medicine; The University of Tokyo; Tokyo Japan