1Department of Orthopaedic Surgery, NTT (Nippon Telegraph and Telephone Corporation) Sapporo Hospital, South 1 West 15, Sapporo 060, Japan, , JP
2Department of Biochemistry, Hokkaido University School of Medicine, Sapporo 060, Japan, , JP
3Department of Orthopaedics, Hokkaido University School of Medicine, Sapporo 060, Japan, , JP
4Institute of Immunological Science, Hokkaido University School of Medicine, Sapporo 060, Japan, , JP
5Department of Orthopaedics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14620, USA, , US