title: Predictors of time to revision and clinical outcomes following revision of metal-on-metal hip replacements for adverse reaction to metal debris.
abstract: We undertook a retrospective cohort study to determine clinical outcomes following the revision of metal-on-metal (MoM) hip replacements for adverse reaction to metal debris (ARMD), and to identify predictors of time to revision and outcomes following revision. Between 1998 and 2012 a total of 64 MoM hips (mean age at revision of 57.8 years; 46 (72%) female; 46 (72%) hip resurfacings and 18 (28%) total hip replacements) were revised for ARMD at one specialist centre. At a mean follow-up of 4.5 years (1.0 to 14.6) from revision for ARMD there were 13 hips (20.3%) with post-operative complications and eight (12.5%) requiring re-revision. The Kaplan-Meier five-year survival rate for ARMD revision was 87.9% (95% confidence interval 78.9 to 98.0; 19 hips at risk). Excluding re-revisions, the median absolute Oxford hip score (OHS) following ARMD revision using the percentage method (0% best outcome and 100% worst outcome) was 18.8% (interquartile range (IQR) 7.8% to 48.3%), which is equivalent to 39/48 (IQR 24.8/48 to 44.3/48) when using the modified OHS. Histopathological response did not affect time to revision for ARMD (p = 0.334) or the subsequent risk of re-revision (p = 0.879). Similarly, the presence or absence of a contralateral MoM hip bearing did not affect time to revision for ARMD (p = 0.066) or the subsequent risk of re-revision (p = 0.178). Patients revised to MoM bearings had higher rates of re-revision (five of 16 MoM hips re-revised; p = 0.046), but those not requiring re-revision had good functional results (median absolute OHS 14.6% or 41.0/48). Short-term morbidity following revision for ARMD was comparable with previous reports. Caution should be exercised when choosing bearing surfaces for ARMD revisions.
authors.affiliation: The Royal Orthopaedic Hospital, Birmingham, B31 2AP, UK.
authors.forename: G S
authors.initials: GS
authors.lastname: Matharu
authors.affiliation: The Royal Orthopaedic Hospital, Birmingham, B31 2AP, UK.
authors.forename: P B
authors.initials: PB
authors.lastname: Pynsent
authors.affiliation: The Royal Orthopaedic Hospital, Birmingham, B31 2AP, UK.
authors.forename: V P
authors.initials: VP
authors.lastname: Sumathi
authors.affiliation: University of Birmingham, Rheumatology Research Group, Institute of Biomedical Research, MRC Centre for Immune Regulation, Birmingham, B15 2WD, UK.
authors.forename: S
authors.initials: S
authors.lastname: Mittal
authors.affiliation: University of Birmingham, Rheumatology Research Group, Institute of Biomedical Research, MRC Centre for Immune Regulation, Birmingham, B15 2WD, UK.
authors.forename: C D
authors.initials: CD
authors.lastname: Buckley
authors.affiliation: The Royal Orthopaedic Hospital, Birmingham, B31 2AP, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Dunlop
authors.affiliation: The Royal Orthopaedic Hospital, Birmingham, B31 2AP, UK.
authors.forename: P A
authors.initials: PA
authors.lastname: Revell
authors.affiliation: The Royal Orthopaedic Hospital, Birmingham, B31 2AP, UK.
authors.forename: M P
authors.initials: MP
authors.lastname: Revell
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D015331:Cohort Studies; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008875:Middle Aged; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Adverse reaction to metal debris; Clinical outcomes; Metal-on-metal; Hip resurfacing; Revision surgery; Total hip replacement