title: Automatic measurement of polyethylene modification in metal-backed artificial hip joints using three-dimensional CT.
abstract: A new method has been developed for automatic measurement of polyethylene linear modification using three-dimensional CT in total hip arthroplasty (THA) and bipolar hemiarthroplasty (BHP). We obtained a three-dimensional digital image of the metal components by widening the maximum window width, adjusting the proper cutoff threshold level, and removing the metal artifact. The centric coordinates of both the metal-backed cup and the femoral head were calculated from this image. Modification was defined as a change in distance between those two points from their original interval. Phantom studies of the accuracy and reproducibility of the method indicated that the average error ranged from 0.02 to 0.12 mm and the standard deviation ranged from 0.01 to 0.05 mm. Clinical in vivo measurement was performed without error of computer software on 19 hips in which modification of highly cross-linked polyethylene components was significantly large.
authors.affiliation: Department of Orthopaedic Surgery, Chiba University School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8677, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Mitsuhashi
authors.forename: Yoshitada
authors.initials: Y
authors.lastname: Harada
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Yanagawa
authors.forename: Koya
authors.initials: K
authors.lastname: Kamikawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitahara
authors.forename: Hideshige
authors.initials: H
authors.lastname: Moriya
mesh_terms: D016477:Artifacts; D003432:Cross-Linking Reagents; D019544:Equipment Failure Analysis; D006622:Hip Prosthesis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020959:Polyethylene; D012984:Software; D013499:Surface Properties; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003432:Cross-Linking Reagents; D020959:Polyethylene