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Title: Stem migration and fretting corrosion of the antirotation pin in the K2/Apex hip system.
Epworth Authors: de Steiger, Richard
Other Authors: Kent, Michael
Edmondson, Mark
Ebert, Jay
Nivbrant, Nils
Kop, Alan
Wood, David
Keywords: Revision Hip Arthroplasty
Metal Pathology
Roentgen Stereophotogrammetric
Fretting Corrosion
Stem Stability
Neck-Stem Interface
Musculoskeletal Clinical Institute, Epworth HealthCare, Victoria, Australia
Issue Date: Mar-2016
Publisher: Elsevier
Citation: J Arthroplasty. 2016 Mar;31(3):727-34.
Abstract: BACKGROUND: Many exchangeable neck hip systems have been withdrawn because of fretting corrosion at the neck/stem coupling. METHOD: Our prospective randomized study evaluating stem stability (Roentgen stereophotogrammetric analysis, dual-energy x-ray absorptiometry) and clinical outcomes between the K2/Apex hip systems was ceased early because of a withdrawal of the stems which had an unfavorably high early revision rate reported in the Australian Orthopaedic Association National Joint Registry (9.3% at 3 years). RESULTS: At 2 years, there are no clinical differences between the stems. Roentgen stereophotogrammetric analysis has identified a high proportion of potentially concerning subsidence and retroversion in both groups, more marked in the K2 stem, although mostly in asymptomatic patients. Dual-energy x-ray absorptiometry has shown similar bone density around the stems. Retrieval analysis of 3 study patients showed fretting corrosion of the antirotation pin and aseptic lymphocyte-dominated vasculitis-associated lesion, with no relationship to bearing type or size. Analysis of 7 further nonstudy K2/Apex stems confirmed similar corrosion. CONCLUSION: This study shows potentially concerning subsidence of both stems and is the first to describe corrosion at the neck-stem interface and a relationship to metal-related pathology.
DOI: 10.1016/j.arth.2015.10.004
PubMed URL:
ISSN: 0883-5403
Journal Title: The Journal of Arthroplasty
Type: Journal Article
Affiliated Organisations: Perth Orthopaedic Institute, Perth, Western Australia, Australia.
CITRA (Centre for Implant Technology and Retrival Analysis) Medical Engineering and Physics, Perth, Western Australia, Australia.
AOA National Joint Registry, Data Management & Analysis Centre, School of Population Health, University of Adelaide, Adelaide, South Australia, Australia.
Type of Clinical Study or Trial: Prospective Study
Appears in Collections:Musculoskeletal

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