Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-Machi, Kanazawa City, 920-8641, Japan

Tomoyuki Kanayama, Junsuke Nakase, Yoshihiro Ishida, Yusuke Yanatori, Naoki Takemoto & Satoru Demura

TK and JN designed the study. JN performed all surgeries. TK performed all ultrasound examinations. YY and YI diagnosed ramp lesions using ultrasound data. NT analyzed all data. All authors interpreted the data and prepared the manuscript. All authors read and approved the final manuscript, and each author believes that the manuscript represents honest work. Tomoyuki Kanayama: Concept, Design, Definition of intellectual content, Literature search, Clinical studies, Experimental studies, Data acquisition, Manuscript preparation, Manuscript editing, Manuscript review, Guarantor. Junsuke Nakase: Concept, Design, Clinical studies, Experimental studies, Manuscript preparation, Manuscript editing, Manuscript review, Guarantor. Yoshihiro Ishida: Concept, Design, Experimental studies, Data acquisition, Manuscript review, Guarantor. Yusuke Yanatori: Concept, Design, Experimental studies, Data acquisition, Manuscript review, Guarantor. Naoki Takemoto: Concept, Design, Statistical analysis, Manuscript review, Guarantor. Satoru Demura: Concept, Design, Manuscript review, Guarantor.

Correspondence to Junsuke Nakase.