title: Clinically insignificant trunnionosis in large-diameter metal-on-polyethylene total hip arthroplasty.
abstract: OBJECTIVE
  Mechanical wear and corrosion at the head-stem junction of total hip arthroplasties (THAs) (trunnionosis) have been implicated in their early revision, most commonly in metal-on-metal (MOM) hips. We can isolate the role of the head-stem junction as the predominant source of metal release by investigating non-MOM hips; this can help to identify clinically significant volumes of material loss and corrosion from these surfaces.
  
  
  METHODS
  In this study we examined a series of 94 retrieved metal-on-polyethylene (MOP) hips for evidence of corrosion and material loss at the taper junction using a well published visual grading method and an established roundness-measuring machine protocol. Hips were retrieved from 74 male and 20 female patients with a median age of 57 years (30 to 76) and a median time to revision of 215 months (2 to 324). The reasons for revision were loosening of both the acetabular component and the stem (n = 29), loosening of the acetabular component (n = 58) and infection (n = 7). No adverse tissue reactions were reported by the revision surgeons.
  
  
  RESULTS
  Evidence of corrosion was observed in 55% of hips. The median Goldberg taper corrosion score was 2 (1 to 4) and the annual rate of material loss at the taper was 0.084 mm3/year (0 to 0.239). The median trunnion corrosion score was 1 (1 to 3).
  
  
  CONCLUSIONS
  We have reported a level of trunnionosis for MOP hips with large-diameter heads that were revised for reasons other than trunnionosis, and therefore may be clinically insignificant.Cite this article: H. S. Hothi, D. Kendoff, C. Lausmann, J. Henckel, T. Gehrke, J. Skinner, A. Hart. Clinically insignificant trunnionosis in large-diameter metal-on-polyethylene total hip arthroplasty. Bone Joint Res 2017;6:52-56. DOI: 10.1302/2046-3758.61.BJR-2016-0150.R2.
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and the Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK h.hothi@ucl.ac.uk.
authors.forename: H S
authors.initials: HS
authors.lastname: Hothi
authors.affiliation: Orthopaedic Department, HELIOS, Endo-Klinik Hamburg, Hamburg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Kendoff
authors.affiliation: Orthopaedic Department, HELIOS, Endo-Klinik Hamburg, Hamburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Lausmann
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and the Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: J
authors.initials: J
authors.lastname: Henckel
authors.affiliation: Orthopaedic Department, HELIOS, Endo-Klinik Hamburg, Hamburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Gehrke
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and the Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: J
authors.initials: J
authors.lastname: Skinner
authors.affiliation: Institute of Orthopaedics and Musculoskeletal Science, University College London and the Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
authors.forename: A
authors.initials: A
authors.lastname: Hart
keywords: Corrosion; Hip; Metal-on-polyethylene; Taper; Wear