title: Implant Optimisation for Primary Hip Replacement in Patients over 60 Years with Osteoarthritis: A Cohort Study of Clinical Outcomes and Implant Costs Using Data from England and Wales.
abstract: BACKGROUND
  Hip replacement is one of the most commonly performed surgical procedures worldwide; hundreds of implant configurations provide options for femoral head size, joint surface material and fixation method with dramatically varying costs. Robust comparative evidence to inform the choice of implant is needed. This retrospective cohort study uses linked national databases from England and Wales to determine the optimal type of replacement for patients over 60 years undergoing hip replacement for osteoarthritis.
  
  
  RESULTS
  Implants included were the commonest brand from each of the four types of replacement (cemented, cementless, hybrid and resurfacing); the reference prosthesis was the cemented hip procedure. Patient reported outcome scores (PROMs), costs and risk of repeat (revision) surgery were examined. Multivariable analyses included analysis of covariance to assess improvement in PROMs (Oxford hip score, OHS, and EQ5D index) (9159 linked episodes) and competing risks modelling of implant survival (79,775 procedures). Cost of implants and ancillary equipment were obtained from National Health Service procurement data.
  
  
  RESULTS
  EQ5D score improvements (at 6 months) were similar for all hip replacement types. In females, revision risk was significantly higher in cementless hip prostheses (hazard ratio, HR = 2.22, p<0.001), when compared to the reference hip. Although improvement in OHS was statistically higher (22.1 versus 20.5, p<0.001) for cementless implants, this small difference is unlikely to be clinically important. In males, revision risk was significantly higher in cementless (HR = 1.95, p = 0.003) and resurfacing implants, HR = 3.46, p<0.001), with no differences in OHS. Material costs were lowest with the reference implant (cemented, range £1103 to £1524) and highest with cementless implants (£1928 to £4285). Limitations include the design of the study, which is intrinsically vulnerable to omitted variables, a paucity of long-term implant survival data (reflecting the duration of data collection), the possibility of revision under-reporting, response bias within PROMs data, and issues associated with current outcome scoring systems, which may not accurately reflect level of improvement in some patients.
  
  
  CONCLUSIONS
  Cement fixation, using a polyethylene cup and a standard sized head offers good outcomes, with the lowest risks and at the lowest costs. The most commonly used cementless and resurfacing implants were associated with higher risk of revision and were more costly, while perceptions of improved function and longevity were unsupported.
authors.affiliation: School of Medicine, Pharmacy and Health, Durham University, Queen's Campus, University Boulevard, Stockton-on-Tees, TS17 6BH, United Kingdom.|The National Joint Registry for England and Wales, London, United Kingdom.|Department of Orthopaedic Surgery, South Tees Hospitals NHS Foundation Trust, Marton Road, Middlesbrough, TS4 3BW, United Kingdom.
authors.forename: Simon S
authors.initials: SS
authors.lastname: Jameson
authors.affiliation: School of Medicine, Pharmacy and Health, Durham University, Queen's Campus, University Boulevard, Stockton-on-Tees, TS17 6BH, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Mason
authors.affiliation: The National Joint Registry for England and Wales, London, United Kingdom.|Department of Orthopaedic Surgery, South Tees Hospitals NHS Foundation Trust, Marton Road, Middlesbrough, TS4 3BW, United Kingdom.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Baker
authors.affiliation: The National Joint Registry for England and Wales, London, United Kingdom.|Department of Orthopaedic Surgery, South Tees Hospitals NHS Foundation Trust, Marton Road, Middlesbrough, TS4 3BW, United Kingdom.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Gregg
authors.affiliation: Department of Orthopaedic Surgery, Newcastle Hospitals NHS Foundation Trust, Freeman Road, High Heaton, Newcastle upon Tyne, NE7 7DN, United Kingdom.
authors.forename: David J
authors.initials: DJ
authors.lastname: Deehan
authors.affiliation: Department of Orthopaedic Surgery, Northumbria Healthcare NHS Foundation Trust, Woodhorn Lane, Ashington, Northumberland, NE63 9JJ, United Kingdom.
authors.forename: Mike R
authors.initials: MR
authors.lastname: Reed
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods / Q000706:statistics & numerical data*; D001843:Bone Cements / Q000737:chemistry; D003362:Cost-Benefit Analysis; D004739:England; D005260:Female; D006622:Hip Prosthesis / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015207:Osteoarthritis, Hip / Q000601:surgery*; D017063:Outcome Assessment, Health Care / Q000191:economics / Q000379:methods / Q000706:statistics & numerical data; D020959:Polyethylene; D016016:Proportional Hazards Models; D012042:Registries / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014852:Wales
chemical_list: D001843:Bone Cements; D020959:Polyethylene