title: Association between fixation technique and revision risk in total hip arthroplasty patients younger than 55 years of age. Results from the Nordic Arthroplasty Register Association.
abstract: OBJECTIVE
  To evaluate implant survival following primary total hip replacement (THR) in younger patients. To describe the diversity in use of cup-stem implant combinations.
  
  
  METHODS
  29,558 primary THRs osteoarthritis (OA) patients younger than 55 years of age performed from 1995 through 2011 were identified using the Nordic Arthroplasty Registry Association database. We estimated adjusted relative risk (aRR) of revision with 95% confidence interval (CI) using Cox regression.
  
  
  RESULTS
  In general, no difference was observed between uncemented and cemented implants in terms of risk of any revision. Hybrid implants were associated with higher risk of any revision (aRR = 1.3, CI: 1.1-1.5). Uncemented implants led to a reduced risk of revision due to aseptic loosening (aRR = 0.5, CI: 0.5-0.6), whereas the risk was similar for hybrid and cemented implants. Compared with cemented implants, both uncemented and hybrid implants led to elevated risk of revision due to other causes, as well as elevated risk of revision due to any reason within 2 years. 183 different uncemented cup-stem implant combinations were registered in Denmark, of these, 172 were used in less than 100 operations which is similar to Norway, Sweden and Finland.
  
  
  CONCLUSIONS
  Uncemented implants perform better in relation to long-term risk of aseptic loosening, whereas both uncemented and hybrid rather than cemented implants in patients younger than 55 years had more short-term revisions because problems due to dislocation, periprosthetic fracture and infection has not yet been completely solved. The vast majority of cup-stem combinations were used in very few operations.
authors.affiliation: Competence Centre for Clinical Epidemiology and Biostatistics, North, Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: abp@dce.au.dk.
authors.forename: A B
authors.initials: AB
authors.lastname: Pedersen
authors.affiliation: Competence Centre for Clinical Epidemiology and Biostatistics, North, Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: fm@dce.au.dk.
authors.forename: F
authors.initials: F
authors.lastname: Mehnert
authors.affiliation: The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway. Electronic address: leif.ivar.havelin@helse-bergen.no.
authors.forename: L I
authors.initials: LI
authors.lastname: Havelin
authors.affiliation: The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway. Electronic address: ove.furnes@helse-bergen.no.
authors.forename: O
authors.initials: O
authors.lastname: Furnes
authors.affiliation: The Swedish Hip Arthroplasty Register, Department of Orthopaedics, Institute of Surgical Sciences, Sahlgrenska University Hospital, University of Gothenburg, Mölndal, Sweden. Electronic address: peter.herberts@vgregion.se.
authors.forename: P
authors.initials: P
authors.lastname: Herberts
authors.affiliation: The Swedish Hip Arthroplasty Register, Department of Orthopaedics, Institute of Surgical Sciences, Sahlgrenska University Hospital, University of Gothenburg, Mölndal, Sweden. Electronic address: johan.karrholm@vgregion.se.
authors.forename: J
authors.initials: J
authors.lastname: Kärrholm
authors.affiliation: The Swedish Hip Arthroplasty Register, Department of Orthopaedics, Institute of Surgical Sciences, Sahlgrenska University Hospital, University of Gothenburg, Mölndal, Sweden. Electronic address: Goran.Garellick@registercentrum.se.
authors.forename: G
authors.initials: G
authors.lastname: Garellick
authors.affiliation: Department of Orthopaedics and Traumatology, Turku University Hospital, Turku, Finland; The Finnish Arthroplasty Register, Finland. Electronic address: Keijo.Makela@tyks.fi.
authors.forename: K
authors.initials: K
authors.lastname: Mäkela
authors.affiliation: The Finnish Arthroplasty Register, Finland; The Coxa Hospital for Joint Replacement, Tampere, Finland. Electronic address: antti.eskelinen@fimnet.fi.
authors.forename: A
authors.initials: A
authors.lastname: Eskelinen
authors.affiliation: Department of Orthopaedic Surgery, Traumatology and Clinical Institute, Odense University Hospital, Odense, Denmark; Danish Hip Arthroplasty Register, Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: Soeren.Overgaard@rsyd.dk.
authors.forename: S
authors.initials: S
authors.lastname: Overgaard
mesh_terms: D000328:Adult; D000367:Age Factors; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000379:methods*; D002484:Cementation; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000209:etiology*; D012042:Registries; D012086:Reoperation / Q000706:statistics & numerical data; D012307:Risk Factors; D012537:Scandinavian and Nordic Countries
keywords: Cohort study; Implant survival; Total hip replacement; Young adults