title: Proximal translation of > 1 mm within the first two years of revision total hip arthroplasty correctly predicts whether or not an acetabular component is loose in 80% of cases: a case-control study with confirmed intra-operative outcomes.
abstract: OBJECTIVE
  The purpose of this study was to determine the sensitivity, specificity and predictive values of previously reported thresholds of proximal translation and sagittal rotation of cementless acetabular components used for revision total hip arthroplasty (THA) at various times during early follow-up.
  
  
  METHODS
  Migration of cementless acetabular components was measured retrospectively in 84 patients (94 components) using Ein-Bild-Rontgen-Analyse (EBRA-Cup) in two groups of patients. In Group A, components were recorded as not being loose intra-operatively at re-revision THA (52 components/48 patients) and Group B components were recorded to be loose at re-revision (42 components/36 patients).
  
  
  RESULTS
  The mean proximal translation and sagittal rotation were significantly higher in Group B than in Group A from three months onwards (p < 0.02). Proximal translation > 1.0 mm within 24 months had a positive predictive value (PPV) of 90% and a specificity of 94%, but a sensitivity of 64%. Proximal translation > 1.0 mm within the first 24 months correctly identified 76 of 94 (81%) of components to be either loose or not loose. However, ten components in Group B (24%) did not migrate proximally above 1.0 mm within the first 60 months.
  
  
  CONCLUSIONS
  The high PPV of EBRA-Cup measurements of proximal translation (90%) shows that this can be used in early follow-up to identify patients at risk of aseptic loosening. The absence of proximal translation within the first 60 months indicates a component is not likely to be loose at re-revision THA although it does not exclude late aseptic loosening as a cause of failure. Cite this article:Bone Joint J2017;99-B:465-74.
authors.affiliation: Dongguk University Gyeongju Hospital, Gyeongju, Gyeongsangbuk-do, South Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Royal Adelaide Hospital, Level 4 Bice Building, North Terrace, Adelaide, SA, Australia and PhD Candidate, Discipline of Orthopaedics and Trauma, The University of Adelaide, Adelaide, SA, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Abrahams
authors.affiliation: Royal Adelaide Hospital, Level 4 Bice Building, Royal Adelaide Hospital, North Terrace, Adelaide, SA, Australia and Discipline of Orthopaedics and Trauma, The University of Adelaide, Adelaide, SA, Australia.
authors.forename: S A
authors.initials: SA
authors.lastname: Callary
authors.affiliation: Villa Stuart Sport Clinic, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: De Ieso
authors.affiliation: Royal Adelaide Hospital, Level 4 Bice Building, North Terrace, Adelaide, SA, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Costi
authors.affiliation: The University of Adelaide, Adelaide, SA, Australia and Clinical Director, Department of Orthopaedics and Trauma, Royal Adelaide Hospital Level 4 Bice Building, North Terrace, Adelaide, SA, Australia.
authors.forename: D W
authors.initials: DW
authors.lastname: Howie
authors.affiliation: The University of Adelaide, Adelaide, SA, Australia and Orthopaedic Consultant, Department of Orthopaedics and Trauma, Royal Adelaide Hospital Level 4 Bice Building, North Terrace, Adelaide, SA, Australia.
authors.forename: L B
authors.initials: LB
authors.lastname: Solomon
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging* / Q000473:pathology; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000209:etiology*; D012086:Reoperation / Q000009:adverse effects
keywords: Acetabular component migration; Aseptic loosening; Ein-Bild-Rontgen-Analyse; Revision total hip arthroplasty