title: The choice between hip prosthetic bearing surfaces in total hip replacement: a protocol for a systematic review and network meta-analysis.
abstract: BACKGROUND
  Prosthetic hip implants have many combinations of bearing surface materials, sizes, and fixation techniques, which can determine the quality of life of patients after primary total hip replacement (THR) and the likelihood of needing revision surgery. When an implant fails, patients require revision THR, which is distressing to the patient and expensive for the health care payer. Primary THR is one of the most common elective procedures performed worldwide, with over 300,000 performed annually in the USA and over 80,000 in England and Wales. It is important to review all available randomised controlled trial (RCT) evidence to determine which implant bearing surface materials, size, and fixation technique are most effective for patients.
  
  
  METHODS
  This is a protocol for a systematic review and meta-analysis of RCTs comparing outcomes of hip implant bearing surfaces, size, and fixation techniques used in THR. Implant combinations compared in the literature include four bearing surface combinations (metal-on-polyethylene, metal-on-metal, ceramic-on-polyethylene, and ceramic-on-ceramic); two femoral head sizes (large vs small heads); and four fixation techniques (uncemented, cemented, hybrid, and reverse hybrids). The primary outcome will be revision surgery. We will also collect data on patient characteristics, mortality, quality of life, and other outcomes. In network meta-analysis, we will estimate the relative effectiveness of every implant bearing surface, head size (large vs small), and fixation permutation, using evidence where implants have been compared directly in an RCT and indirectly through common comparators in different RCTs.
  
  
  CONCLUSIONS
  There has been much debate about materials used for prosthetic implants in THR. Different combinations of prosthetic materials, sizes, and fixation, can vary widely in cost and fail at different rates for different patient groups. Given the number of THRs performed yearly, and the increasing use of expensive implants, it is important to review evidence to inform surgeons, patients, and health care providers of optimal implant bearing combinations for given patient characteristics. This review will inform a cost-effectiveness model that will include evidence from other sources, to determine the most effective and cost-effective implant bearing combination for patients.
  
  
  BACKGROUND
  PROSPERO CRD42015019435.
authors.affiliation: School of Social and Community Medicine, University of Bristol Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. e.marques@bristol.ac.uk.
authors.forename: Elsa M R
authors.initials: EM
authors.lastname: Marques
authors.affiliation: School of Social and Community Medicine, University of Bristol Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. rachel.humphriss@bristol.ac.uk.
authors.forename: Rachel
authors.initials: R
authors.lastname: Humphriss
authors.affiliation: School of Social and Community Medicine, University of Bristol Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. nicky.welton@bristol.ac.uk.
authors.forename: Nicky J
authors.initials: NJ
authors.lastname: Welton
authors.affiliation: School of Social and Community Medicine, University of Bristol Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. julian.higgins@bristol.ac.uk.
authors.forename: Julian P T
authors.initials: JP
authors.lastname: Higgins
authors.affiliation: School of Social and Community Medicine, University of Bristol Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. william.hollingworth@bristol.ac.uk.
authors.forename: William
authors.initials: W
authors.lastname: Hollingworth
authors.affiliation: School of Social and Community Medicine, University of Bristol Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. ja.lopez-lopez@bristol.ac.uk.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Lopez-Lopez
authors.affiliation: School of Social and Community Medicine, University of Bristol Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. howard.thom@bristol.ac.uk.
authors.forename: Howard
authors.initials: H
authors.lastname: Thom
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol Learning & Research Building (Level 1), Southmead Hospital, Bristol, BS10 5NB, UK. l.p.hunt@bristol.ac.uk.
authors.forename: Linda P
authors.initials: LP
authors.lastname: Hunt
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol Learning & Research Building (Level 1), Southmead Hospital, Bristol, BS10 5NB, UK. ashley.blom@nbt.nhs.uk.
authors.forename: Ashley W
authors.initials: AW
authors.lastname: Blom
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol Learning & Research Building (Level 1), Southmead Hospital, Bristol, BS10 5NB, UK. andy.beswick@bristol.ac.uk.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Beswick
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D006622:Hip Prosthesis; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D000078202:Systematic Reviews as Topic; D015201:Meta-Analysis as Topic
references.citation: Stat Med. 2010 Mar 30;29(7-8):932-44
references.pmid: 20213715
references.citation: Hip Int. 2009 Jan-Mar;19(1):36-40
references.pmid: 19455500
references.citation: BMJ. 2005 Oct 15;331(7521):897-900
references.pmid: 16223826
references.citation: Med Decis Making. 2013 Apr;33(3):369-80
references.pmid: 23457025
references.citation: Stat Med. 1995 Feb 28;14(4):395-411
references.pmid: 7746979
references.citation: Proc Inst Mech Eng H. 2000;214(4):331-47
references.pmid: 10997055
references.citation: J Bone Joint Surg Br. 2011 Aug;93(8):1017-20
references.pmid: 21768622
references.citation: J Bone Joint Surg Br. 1996 Mar;78(2):185-90
references.pmid: 8666621
references.citation: Health Technol Assess. 2015 Jan;19(10):1-668, vii-viii
references.pmid: 25634033
references.citation: BMJ. 2003 Sep 6;327(7414):557-60
references.pmid: 12958120
references.citation: Ann Rheum Dis. 1997 Aug;56(8):455-7
references.pmid: 9306866
references.citation: Stat Med. 2004 Oct 30;23(20):3105-24
references.pmid: 15449338
references.citation: BMJ. 2015;349:g7647
references.pmid: 25555855
references.citation: Orthop Rev (Pavia). 2013 Mar 15;5(1):e8
references.pmid: 23705066
references.citation: Stat Med. 2007 Sep 10;26(20):3681-99
references.pmid: 17285571
references.citation: Med Decis Making. 2013 Jul;33(5):607-17
references.pmid: 23104435
references.citation: J Bone Joint Surg Am. 1969 Jun;51(4):737-55
references.pmid: 5783851
references.citation: BMJ. 2011;343:d4002
references.pmid: 21784880
references.citation: Med Decis Making. 2013 Jul;33(5):641-56
references.pmid: 23804508
references.citation: J Rheumatol. 1988 Dec;15(12):1833-40
references.pmid: 3068365
references.citation: Stat Methods Med Res. 2008 Jun;17(3):279-301
references.pmid: 17925316
references.citation: Acta Orthop Scand. 2003 Aug;74(4):380-8
references.pmid: 14521286
references.citation: Ann Rheum Dis. 2006 Oct;65(10):1346-50
references.pmid: 16439438
references.citation: Lancet. 2012 Nov 17;380(9855):1759-66
references.pmid: 23036895
references.citation: Lancet. 2012 Mar 31;379(9822):1199-204
references.pmid: 22417410
references.citation: BMJ. 2015;350:h756
references.pmid: 25752749