Liaw C.-K.RONG-SEN YANGHou S.-M.Wu T.-Y.Fuh C.-S.2021-05-312021-05-3120081471-2474https://www.scopus.com/inward/record.uri?eid=2-s2.0-46149121516&doi=10.1186%2f1471-2474-9-87&partnerID=40&md5=184cb9ee7f4481435b58cb166c96f863https://scholars.lib.ntu.edu.tw/handle/123456789/563752Background. Kobelji? et al. recently reported a numeric table method to provide precise rotational osteotomy which is a well established orthopaedic procedure. The numeric table requires four pages in length that is rather inconvenient during performing an osteotomy operation Methods. We thus develop our own method by summarizing the data of the four-page table into a small ruler, which is easy to carry and use in operation room. An electrical version of this ruler is also available. We also build a computer model to verify Kobelji? et al. method. Results. The error of Kobelji? et al. is between -37% to 16% (mean ± SD = -6% ± 9%). We verify our ruler by calculating the absolute difference between our method and that of Kobelji? et al. The difference is less than 0.1 mm. Conclusion. Our ruler is convenient for practical use for the rotational osteotomy procedure with equal precision. Further clinical verification is needed to justify its real significance. ? 2008 Liaw et al; licensee BioMed Central Ltd.[SDGs]SDG3article; biomechanics; computer; medical literature; medical research; orthopedic surgery; osteotomy; biological model; bone disease; computer assisted tomography; computer simulation; human; instrumentation; intraoperative period; methodology; radiography; rotation; standard; Bone Diseases; Computer Simulation; Humans; Intraoperative Period; Models, Biological; Osteotomy; Rotation; Tomography, X-Ray Computed; Weights and Measuresjournal article10.1186/1471-2474-9-87185579992-s2.0-46149121516