title: Revision of Metal-on-metal Hip Arthroplasty with Well Fixed and Positioned Acetabular Component Using a Dual-mobility Head and Review of Literature.
abstract: BACKGROUND
  As a consequence of use of metal-on-metal hip arthroplasties some patients have precised revision for pain or metal hipersensivity reactions among other causes. We propose to salvage monoblock acetabular component and femoral component using a dual-mobility head and perform a lower morbidity operation in young patients preserving host bone stock in cases with well fixed and positioned components.
  
  
  OBJECTIVE
  (1) What clinical problems have been reported in patients with Metal-on-metal hip arthroplasties? (2) Could the tribocorrosion potentially cause a fracture of neck femoral component? (3) Can be the dual-mobility head a recourse in metal-on-metal hip revision?
  
  
  METHODS
  Ten patients were revised for pain or/and raised Cobalt/Chromium levels between August 2012 and December 2015. In three cases femoral neck component was fractured and femoral revision was necessary. In four hips, acetabular and femoral components could be maintained. Age, body index mass, ion levels, acetabular position, size of acetabular component and femoral head, approach, blood transfunsion and time of hospitalization were analized.
  
  
  RESULTS
  At a mean follow-up of 25,6 months (6 to 45) the mean postoperative HHS was 92. It was not statistically significant because several patients were low sintomatic before surgery, but had raised Cobalt/Chromium levels in the blood. All patients had near-normal levels of Cobalt/Chromium during the first 6 months after revision surgery. No relevant complications were reported.
  
  
  CONCLUSIONS
  The use of dual-mobility head can be an acceptable option to revise metal-on-metal arthroplasties correctly oriented with abscence of loosening or infection signs and keeping bone stock in young patients.
authors.affiliation: Fundació Althaia, Xarxa Assistencial Universitària de Manresa, Traumatology and Orthopedic Surgery Department, C/Dr Joan Soler S/N 08243 Manresa, (93-8759300), Spain.
authors.forename: Guillem
authors.initials: G
authors.lastname: Figueras
authors.affiliation: Fundació Althaia, Xarxa Assistencial Universitària de Manresa, Traumatology and Orthopedic Surgery Department, C/Dr Joan Soler S/N 08243 Manresa, (93-8759300), Spain.
authors.forename: Ramón Vives
authors.initials: RV
authors.lastname: Planell
authors.affiliation: Fundació Althaia, Xarxa Assistencial Universitària de Manresa, Traumatology and Orthopedic Surgery Department, C/Dr Joan Soler S/N 08243 Manresa, (93-8759300), Spain.
authors.forename: Ramón Serra
authors.initials: RS
authors.lastname: Fernàndez
authors.affiliation: Fundació Althaia, Xarxa Assistencial Universitària de Manresa, Traumatology and Orthopedic Surgery Department, C/Dr Joan Soler S/N 08243 Manresa, (93-8759300), Spain.
authors.forename: Joan Camí
authors.initials: JC
authors.lastname: Biayna
keywords: Dual-mobility; Femoral neck fracture component; Introduction metal ions levels; Metal-on-metal hip arthroplasty; Resurfacing hip revisión; Revision hip arthroplasty