title: Asymptomatic pseudotumours after metal-on-metal hip resurfacing show little change within one year.
abstract: The aim of this study was to establish the natural course of unrevised asymptomatic pseudotumours after metal-on-metal (MoM) hip resurfacing during a six- to 12-month follow-up period. We used repeated metal artefact reduction sequence (MARS)-magnetic resonance imaging (MRI), serum metal ion analysis and clinical examination to study 14 unrevised hips (mean patient age 52.7 years, 46 to 68, 5 female, 7 male) with a pseudotumour and 23 hips (mean patient age 52.8 years, 38 to 69, 7 female, 16 male) without a pseudotumour. The mean post-operative time to the first MARS-MRI scan was 4.3 years (2.2 to 8.3), and mean time between the first and second MARS-MRI scan was eight months (6 to 12). At the second MRI scan, the grade of severity of the pseudotumour had not changed in 35 hips. One new pseudotumour (Anderson C2 score, moderate) was observed, and one pseudotumour was downgraded from C2 (moderate) to C1 (mild). In general, the characteristics of the pseudotumours hardly changed. Repeated MARS-MRI scans within one year in patients with asymptomatic pseudotumours after MoM hip resurfacing showed little or no variation. In 23 patients without pseudotumour, one new asymptomatic pseudotumour was detected. This is the first longitudinal study on the natural history of pseudotumours using MARS-MRI scans in hip resurfacing, and mirrors recent results for 28 mm diameter MoM total hip replacement.
authors.affiliation: St. Anna Hospital, Department of Orthopaedic Surgery, Bogardeind 2, 5664 EH Geldrop, the Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: van der Weegen
authors.forename: K
authors.initials: K
authors.lastname: Brakel
authors.forename: R J
authors.initials: RJ
authors.lastname: Horn
authors.forename: H J
authors.initials: HJ
authors.lastname: Hoekstra
authors.forename: T
authors.initials: T
authors.lastname: Sijbesma
authors.forename: P
authors.initials: P
authors.lastname: Pilot
authors.forename: R G H H
authors.initials: RG
authors.lastname: Nelissen
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006104:Granuloma, Plasma Cell / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008875:Middle Aged; D011379:Prognosis; D011474:Prosthesis Design; D012086:Reoperation; D012720:Severity of Illness Index
chemical_list: D002857:Chromium; D003035:Cobalt
keywords: Longitudinal; MARS-MRI; Metal-on-metal; Pseudotumours; Resurfacing; Treatment