Katsuhisa Yoshikawa, Nobuto Kitamura, Takayuki Kurokawa, Jian Ping Gong, Yutaka Nohara and Kazunori Yasuda*
* Corresponding author: Kazunori Yasuda yasukaz@med.hokudai.ac.jp
BMC Musculoskeletal Disorders 2013, 14:56 doi:10.1186/1471-2474-14-56