1. Department of Orthopaedic Surgery, Aichi-ken Saiseikai Hospital, 451-0052, 1-1-18 Sakou, Nishiku, Nagoya City, Japan.
2. Department of Orthopaedic Surgery, Nagoya University Graduate School of Medical Sciences, 446-8550, 65 Tsurumai-cho, Showa-ku, Nagoya City, Japan.
3. Department of Health Promotion and Preventive Medicine, Nagoya City University Graduate School of Medical Sciences, 467-8601, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya City, Japan.
4. Department of Orthopaedics, University Hospital, S-221 85, Lund, Sweden.