title: The effect of using components from different manufacturers on the rate of wear and corrosion of the head-stem taper junction of metal-on-metal hip arthroplasties.
abstract: OBJECTIVE
  Surgeons have commonly used modular femoral heads and stems from different manufacturers, although this is not recommended by orthopaedic companies due to the different manufacturing processes. We compared the rate of corrosion and rate of wear at the trunnion/head taper junction in two groups of retrieved hips; those with mixed manufacturers (MM) and those from the same manufacturer (SM).
  
  
  METHODS
  We identified 151 retrieved hips with large-diameter cobalt-chromium heads; 51 of two designs that had been paired with stems from different manufacturers (MM) and 100 of seven designs paired with stems from the same manufacturer (SM). We determined the severity of corrosion with the Goldberg corrosion score and the volume of material loss at the head/stem junction. We used multivariable statistical analysis to determine if there was a significant difference between the two groups.
  
  
  RESULTS
  We found no significant difference in the corrosion scores of the two groups. The median rate of material loss at the head/stem junction for the MM and SM groups were 0.39 mm(3)/year (0.00 to 4.73) and 0.46 mm(3)/year (0.00 to 6.71) respectively; this difference was not significant after controlling for confounding factors (p = 0.06).
  
  
  CONCLUSIONS
  The use of stems with heads of another manufacturer does not appear to affect the amount of metal lost from the surfaces between these two components at total hip arthroplasty. Other surgical, implant and patient factors should be considered when determining the mechanisms of failure of large diameter metal-on-metal hip arthroplasties. Cite this article: Bone Joint J 2016;98-B:917-24.
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and London Implant Retrieval Centre (LIRC), Biomedical Engineering, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: R K
authors.initials: RK
authors.lastname: Whittaker
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and London Implant Retrieval Centre (LIRC), Biomedical Engineering, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: H S
authors.initials: HS
authors.lastname: Hothi
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and London Implant Retrieval Centre (LIRC), Biomedical Engineering, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Meswania
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and London Implant Retrieval Centre (LIRC), Biomedical Engineering, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: R
authors.initials: R
authors.lastname: Berber
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and London Implant Retrieval Centre (LIRC), Biomedical Engineering, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: G W
authors.initials: GW
authors.lastname: Blunn
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and London Implant Retrieval Centre (LIRC), Biomedical Engineering, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: J A
authors.initials: JA
authors.lastname: Skinner
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and London Implant Retrieval Centre (LIRC), Biomedical Engineering, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Hart
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D002857:Chromium; D002858:Chromium Alloys; D003035:Cobalt; D003343:Corrosion; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D061825:Metal-on-Metal Joint Prostheses; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D014025:Titanium
chemical_list: D002858:Chromium Alloys; D002857:Chromium; D003035:Cobalt; D014025:Titanium
keywords: Hip; Retrieval