title: Computer-assisted preoperative planning for reduction of proximal femoral fracture using 3-D-CT data.
abstract: This paper describes procedures for repositioning calculations of fractured bone fragments using 3-D-computed tomography (CT), aimed at preoperative planning for computer-guided fracture reduction of the proximal femur. Fracture boundaries of the bone fragments, as "fracture lines (FLs)," and the mirror-transformed contralateral femur shape extracted from 3-D-CT were used for repositioning of the fragments. We first describe a method for extracting FLs based on 3-D curvature analysis and then formulate repositioning methods based on registration of bone fragments using the following three constraints: 1) contralateral (CL) femur shape; 2) FLs; and 3) both CL femur shape and fracture lines, as "both constraints". We performed experiments using CT datasets from five simulated and four real patients with proximal femoral fracture. We evaluated the rotation error in reposition calculations and the contact ratio between repositioned fragment boundaries, which are crucial for the recovery of proper functional axes and bone adhesion of fragments, respectively. Experimental results showed that good accuracy and stability were attainable when registration using both constraints was performed after registration using the fracture-line constraint. On average, 6.0 degrees +/-0.8 degrees in rotation error and 89%+/-3 % in contact ratio were obtained without providing precise initial values.
authors.affiliation: Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Okada
authors.forename: Yuta
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Koyama
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
authors.forename: Yen-Wei
authors.initials: YW
authors.lastname: Chen
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yonenobu
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Sato
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003658:Decision Making, Computer-Assisted; D005264:Femoral Fractures / Q000000981:diagnostic imaging* / Q000601:surgery*; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed