title: Hip surgery and its evidence base: progress over a decade?
abstract: BACKGROUND
  The burden of traumatic and elective hip surgery is set to grow. With an increasing number of techniques and implants against the background of an aging population, the emphasis on evidence-based treatment has never been greater. The purpose of this study was to assess changes in the levels of evidence in the hip literature over a decade.
  
  
  METHODS
  Articles pertaining to hip surgery from the years 2000 and 2010 in Hip International, Journal of Arthroplasty, Journal of Bone and Joint Surgery and The Bone and Joint Journal were analysed. Articles were ranked by a five-point level of evidence scale and by type of study, according to guidelines from the Centre for Evidence-based Medicine.
  
  
  RESULTS
  531 articles were analysed from 48 countries. The kappa value for the inter-observer reliability showed excellent agreement between the reviewers for study type (κ = 0.956, P < 0.01) and for levels of evidence (κ = 0.772, P < 0.01). Between 2000 and 2010, the overall percentage of high-level evidence (levels I and II) studies more than doubled (12 to 31 %, P < 0.001). The most frequent study type was therapeutic; the USA and UK were the largest producers of published work in these journals, with contributions from other countries increasing markedly over the decade.
  
  
  CONCLUSIONS
  There has been a significant increase in high levels of evidence in hip surgery over a decade (P < 0.001). We recommend that all orthopaedic journals consider implementing compulsory declaration by authors of the level of evidence to help enhance quality of evidence.
  
  
  METHODS
  Level 2: economic and decision analysis.
authors.affiliation: Whipps Cross University Hospital, Whipps Cross Road, London, E11 1NR, UK.
authors.forename: Kamrul
authors.initials: K
authors.lastname: Hasan
authors.affiliation: Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK.
authors.forename: Shivakumar
authors.initials: S
authors.lastname: Shankar
authors.affiliation: Barnet General Hospital, Wellhouse Lane, Barnet, Hertfordshire, EN5 3DJ, UK. aadharsharma0@gmail.com.
authors.forename: Aadhar
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Royal National Throat, Nose and Ear Hospital, Grays Inn Road, London, WC1X 8DA, UK.
authors.forename: Alison
authors.initials: A
authors.lastname: Carter
authors.affiliation: Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK.
authors.forename: Razi
authors.initials: R
authors.lastname: Zaidi
authors.affiliation: MRC Clinical Trials Unit, London, WC2B 6NH, UK.
authors.forename: Suzie
authors.initials: S
authors.lastname: Cro
authors.affiliation: Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK.
authors.forename: John
authors.initials: J
authors.lastname: Skinner
authors.affiliation: Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK.
authors.forename: Andy
authors.initials: A
authors.lastname: Goldberg
mesh_terms: D019644:Arthroplasty, Replacement, Hip; D019317:Evidence-Based Medicine; D006615:Hip / Q000601:surgery*; D006801:Humans; D009985:Orthopedics
keywords: Arthroplasty; Evidence-based medicine; Hip