title: Investigation of Taper Failure in a Contemporary Metal-on-Metal Hip Arthroplasty System Through Examination of Unused and Explanted Prostheses.
abstract: BACKGROUND
  Large-diameter (≥36-mm) metal-on-metal (MoM) total hip replacements have been shown to fail at an unacceptably high rate. Globally, the DePuy Pinnacle prosthesis was the most widely used device of this type. There is evidence to suggest that one of the main reasons for the poor clinical performance of large-diameter MoM prostheses is the metal debris released from the head-stem taper junction-i.e., taper junction failure. The aim of this study was to investigate variation in the as-manufactured finish of the female taper surface and to determine its influence on material loss. We hypothesized that rougher surfaces with higher relative material peaks would be significantly associated with greater taper wear rates.
  
  
  METHODS
  We analyzed 93 Articul/eze femoral head tapers with a 36-mm bearing diameter that had been used in combination with a Corail titanium uncemented stem. The influence of the surface topography of the as-manufactured female taper surface on taper wear was examined by means of a multiple regression model, taking into account other known variables.
  
  
  RESULTS
  We identified great variation in the as-manufactured surface finish of the female taper surface, with a range of measured Ra values from 0.14 to 4.20 μm. The roughness of the female taper surface appeared to be the most important variable associated with taper wear (p < 0.001). The best-fitting regression model, including duration in vivo, head offset, reduced peak height (Rpk) value, stem shaft angle, and bearing surface wear rate, explained approximately 44% of the variation in taper wear rates.
  
  
  CONCLUSIONS
  We concluded that the roughness of the female taper surface appears to be a significant factor in metal debris release from head-stem taper junctions.
  
  
  CONCLUSIONS
  This study shows evidence that previously unappreciated variations in manufacturing processes may have a major impact on the clinical outcomes of patients.
authors.affiliation: 1Farndale House, University Hospital of North Tees, Middlesbrough, England 2University Hospitals of Coventry and Warwickshire, Coventry, England 3Newcastle University, Newcastle Upon Tyne, England 4University Hospital of North Tees, Stockton-on-Tees, England 5Freeman Hospital, Newcastle Upon Tyne, England 6University Hospital of North Durham, Durham, England 7Sunderland Royal Hospital, Sunderland, England 8Queen Elizabeth Hospital, Gateshead, England 9Southern General Hospital, Glasgow, Scotland 10Nuffield Health Tees Hospital, Stockton-on-Tees, England.
authors.forename: David
authors.initials: D
authors.lastname: Langton
authors.forename: Imran
authors.initials: I
authors.lastname: Ahmed
authors.forename: Peter
authors.initials: P
authors.lastname: Avery
authors.forename: Martin
authors.initials: M
authors.lastname: Bone
authors.forename: Nicholas
authors.initials: N
authors.lastname: Cooke
authors.forename: David
authors.initials: D
authors.lastname: Deehan
authors.forename: Patrick
authors.initials: P
authors.lastname: Duffy
authors.forename: Pedro
authors.initials: P
authors.lastname: Foguet
authors.forename: Stephen
authors.initials: S
authors.lastname: Green
authors.forename: James
authors.initials: J
authors.lastname: Holland
authors.forename: Anwar
authors.initials: A
authors.lastname: Jafri
authors.forename: Lee
authors.initials: L
authors.lastname: Longstaff
authors.forename: James
authors.initials: J
authors.lastname: Lord
authors.forename: Jonathan
authors.initials: J
authors.lastname: Loughead
authors.forename: R M Dominic
authors.initials: RM
authors.lastname: Meek
authors.forename: Helen
authors.initials: H
authors.lastname: Murray
authors.forename: Ananda
authors.initials: A
authors.lastname: Nanu
authors.forename: A V F
authors.initials: AV
authors.lastname: Nargol
authors.forename: Susan Claire
authors.initials: SC
authors.lastname: Scholes
authors.forename: Raghavendra Prasad
authors.initials: RP
authors.lastname: Sidaginamale
authors.forename: Susan
authors.initials: S
authors.lastname: Waller
authors.forename: Thomas
authors.initials: T
authors.lastname: Joyce
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D003343:Corrosion; D020878:Device Removal; D019544:Equipment Failure Analysis; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation