title: How to evaluate three dimensional angle error from plain radiographs.
abstract: Evaluating three-dimensional angle error is necessary because we cannot get every patient's CT or MRI at all times. Creating a method that can calculate angle error from plain radiographs is therefore important. Using vector and trigonometric mathematics, we gradually deduct our formula which can calculate angle error from goal angles (the angles we plan to achieve before operation) to result angles (the angles we get after operation) by two perpendicular radiographs. We also encode it into Micorsoft Excel (Redmond Campus, Redmond, Washington, U.S.) so that it becomes more user-friendly. We hope this tool can be used when evaluating TKR, corrective osteotomy, fracture fixation, and so on.
authors.affiliation: Department of Orthopaedics, Shin Kong Wu Ho-Su Memorial Hospital and Health System, Taipei city 11101, Taiwan; Department of Orthopaedics, College of Medicine, National Taiwan University & Hospital, Taipei city 10002, Taiwan; Department of Healthcare Information and Management, School of Health Technology, Ming Chuan University, TaoYuan city 33348, Taiwan; College of Medicine, Fu Jen Catholic University, New Taipei city 24205, Taiwan.
authors.forename: Chen-Kun
authors.initials: CK
authors.lastname: Liaw
authors.forename: Tai-Yin
authors.initials: TY
authors.lastname: Wu
authors.forename: Sheng-Mou
authors.initials: SM
authors.lastname: Hou
authors.forename: Rong-Sen
authors.initials: RS
authors.lastname: Yang
authors.forename: Chiou-Shann
authors.initials: CS
authors.lastname: Fuh
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D007720:Knee Prosthesis; D008954:Models, Biological; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging* / Q000601:surgery
keywords: plain radiograph; three dimensional angle; two dimensional angle