title: A systematic review of radiographic definitions of foot osteoarthritis in population-based studies.
abstract: OBJECTIVE
  To identify the methods used in population-based epidemiological studies to diagnose radiographic foot osteoarthritis (OA) and to estimate the population prevalence of radiographic foot OA.
  
  
  METHODS
  Electronic databases searched included Medline, Embase, CINAHL and Ageline (inception to May 2009). The search strategy combined search terms for radiography, OA, foot, and specific foot joints. Predetermined selection criteria were applied. Data extracted from each paper included: sample population, radiographic views taken, foot joints examined, scoring system used, definition of OA applied, reliability of radiographic scoring and prevalence of radiographic OA in the foot.
  
  
  RESULTS
  Titles and abstracts of 1035 papers were reviewed and full-texts of 21 papers were obtained. Fifteen papers met inclusion criteria and a further 12 papers were included after screening references. Radiographic views were frequently not specified (NS) but a combination of antero-posterior (AP) and lateral (Lat) views was most commonly reported. The first metatarsophalangeal (MTP) joint was the most commonly examined joint (n=20, 74%). Nineteen studies (70%) used the Kellgren and Lawrence (K&L) grading system, 95% of which defined OA as K&L grade> or =2. Estimates of the prevalence of radiographic first MTP joint OA (defined as K&L> or =2) in middle-aged to older adults ranged from 6.3 to 39%. Significant statistical heterogeneity prevented pooling of prevalence estimates.
  
  
  CONCLUSIONS
  There are comparatively few studies examining radiographic foot OA. Existing studies mainly focus on the first MTP joint and use the K&L grading system. Future studies are needed to quantify the prevalence of radiographic OA at the different joint complexes within the foot.
authors.affiliation: Arthritis Research Campaign National Primary Care Centre, Primary Care Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom. bansari191@yahoo.co.uk
authors.forename: B
authors.initials: B
authors.lastname: Trivedi
authors.forename: M
authors.initials: M
authors.lastname: Marshall
authors.forename: J
authors.initials: J
authors.lastname: Belcher
authors.forename: E
authors.initials: E
authors.lastname: Roddy
mesh_terms: D033023:Foot Joints / Q000000981:diagnostic imaging*; D006801:Humans; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D011859:Radiography; D012720:Severity of Illness Index