title: Longitudinal magnetic resonance imaging of pseudotumors following metal-on-metal total hip arthroplasty.
abstract: The purpose of the study was to determine the natural history of pseudotumors following metal-on-metal total hip arthroplasty (THA) using magnetic resonance imaging (MRI). Initial MRI was conducted at a mean of 36months postoperatively. Follow-up MRI was performed at a mean of 20months after the detection of 24 asymptomatic pseudotumors. Pseudotumor size was determined on MRI. The mean pseudotumor size changed from 729mm(2) to 877mm(2). Pseudotumors increased in size in eight and decreased in six. Ten hips showed no changes. The bigger the pseudotumor size, the more likely the size would increase. In conclusion, pseudotumors frequently change in size. A single MRI study in the clinical decision-making process should be avoided and a longitudinal study should be performed.
authors.affiliation: Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu City, Mie, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu City, Mie, Japan.
authors.forename: Noriki
authors.initials: N
authors.lastname: Miyamoto
authors.affiliation: Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu City, Mie, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Miyazaki
authors.affiliation: Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu City, Mie, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Wakabayashi
authors.affiliation: Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu City, Mie, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sudo
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D005549:Foreign-Body Reaction / Q000175:diagnosis* / Q000209:etiology; D006615:Hip; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008875:Middle Aged
keywords: complications; magnetic resonance imaging; metal-on-metal; pseudotumor; total hip arthroplasty