title: Femoro-tibial knee osteoarthritis: One or two X-rays? Results from a population-based study.
abstract: OBJECTIVE
  Our objective was to compare the use of both anteroposterior (AP) extended-knee X-ray and semi-flexed X-ray (current gold standard) versus the use of semi-flexed X-ray alone to detect femoro-tibial osteoarthritis (OA).
  
  
  METHODS
  Individuals 40 to 75 years of age with symptomatic hip and/or knee OA (Kellgren/Lawrence [KL] score≥2) were recruited using a multiregional prevalence survey in France. Both AP and schuss X-rays were performed and read; two years later, the same examiner, blinded to the results of the first reading, performed a second reading of the schuss X-ray. We compared the KL stages of each knee and analyzed osteophyte detection and localization, joint space narrowing (JSN), and the relationship to obesity.
  
  
  RESULTS
  The analysis included 350 participants with OA of various stages. Comparing the two readings showed that a higher proportion of patients had KL≥2 when the two X-ray views were combined (right knee: P<0.0001; left knee: P<0.001). There were no differences when using the schuss X-ray alone versus in combination with an AP X-ray in terms of detecting JSN, osteophytes. A comparison of schuss X-ray alone versus AP X-ray alone demonstrated the superiority of the schuss view for evaluating JSN (P=0.0001 and P=0.0001) and no difference in osteophyte detection.
  
  
  CONCLUSIONS
  Our study shows that the schuss view alone was sufficient for detecting knee osteophytes and JSN. Using one X-ray rather than two will reduce medical costs and irradiation burden. Using two views seems preferable for epidemiological studies.
authors.affiliation: Rheumatology Department, LAHMESS Laboratory EA 6309, University Sophia-Antipolis, hôpital l'Archet 1, CHU de Nice, 262, avenue Saint-Antoine-de-Ginestière, 06202 Nice, France. Electronic address: roux101fr@yahoo.fr.
authors.forename: Christian-Hubert
authors.initials: CH
authors.lastname: Roux
authors.affiliation: Department of Rheumatology, Purpan University Hospital, 31059 Toulouse cedex 9, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Mazieres
authors.affiliation: Department of Rheumatology, Purpan University Hospital, 31059 Toulouse cedex 9, France.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Verrouil
authors.affiliation: EA 4360 Apemac, Lorraine University, 54505 Vandœuvre-lès-Nancy, France.
authors.forename: Anne-Christine
authors.initials: AC
authors.lastname: Rat
authors.affiliation: Inserm ERI 12, service de rhumatologie, Amiens University Hospital, CHU Nord, 80080 Amiens, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Fardellone
authors.affiliation: Department of Rheumatology, université Pierre-et-Marie-Curie - Sorbonne universités, AP-HP (Assistance publique-hôpitaux de Paris), Pitié-Salpêtrière Hospital, 75013 Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Fautrel
authors.affiliation: Department of Internal Medicine, Assistance publique-hôpitaux de Paris, hôpital européen Georges-Pompidou, 75908 Paris, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Pouchot
authors.affiliation: Rheumatology Department, Cavale-Blanche, University Hospital and EA 2216, université Bretagne occidentale, 29609 Brest cedex, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Saraux
authors.affiliation: EA 4360 Apemac, Lorraine University, 54505 Vandœuvre-lès-Nancy, France.
authors.forename: Francis
authors.initials: F
authors.lastname: Guillemin
authors.affiliation: Rheumatology Department, LAHMESS Laboratory EA 6309, University Sophia-Antipolis, hôpital l'Archet 1, CHU de Nice, 262, avenue Saint-Antoine-de-Ginestière, 06202 Nice, France.
authors.forename: Liana
authors.initials: L
authors.lastname: Euller-Ziegler
authors.affiliation: Biostatistics and Epidemiology Unit, Assistance publique-hôpitaux de Paris, Hôtel-Dieu, 75004 Paris, France.
authors.forename: Joël
authors.initials: J
authors.lastname: Coste
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging*; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging*; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging
keywords: Diagnosis; Knee osteoarthritis; Semi-flexed X-ray