title: Reliability, validity and feasibility of nail ultrasonography in psoriatic arthritis.
abstract: OBJECTIVE
  To determine the feasibility, reliability and validity of nails ultrasonography in psoriatic arthritis as an outcome measure.
  
  
  METHODS
  Pilot prospective single-centre study of eight ultrasonography parameters in B mode and power Doppler concerning the distal interphalangeal (DIP) joint, the matrix, the bed and nail plate. Intra-observer and inter-observer reliability was evaluated for the seven quantitative parameters (ICC and kappa). Correlations between ultrasonography and clinical variables were searched to assess external validity. Feasibility was assessed by the time to carry out the examination and the percentage of missing data.
  
  
  RESULTS
  Twenty-seven patients with psoriatic arthritis (age 55.0±16.2 years, disease duration 13.4±9.4 years) were included. Of these, 67% presented nail involvement on ultrasonography vs 37% on physical examination (P<0.05). Reliability was good (ICC and weighted kappa>0.75) for the seven quantitative parameters, except for synovitis of the DIP joint in B mode. The synovitis of the DIP joint revealed by ultrasonography correlated with the total number of clinical synovitis and Doppler US of the nail (matrix and bed). Doppler US of the matrix correlated with VAS pain but not with the ASDAS-CRP or with clinical enthesitis. No significant correlation was found with US nail thickness.
  
  
  CONCLUSIONS
  The feasibility and reliability of ultrasonography of the nail in psoriatic arthritis appear to be satisfactory. Among the eight parameters evaluated, power Doppler of the matrix which correlated with local inflammation (DIP joint and bed) and with VAS pain could become an interesting outcome measure, provided that it is also sensitive to change.
authors.affiliation: Service de rhumatologie, hôpital du Bocage, CHU de Dijon, 14, rue Gaffarel, 21000 Dijon, France.
authors.forename: Anaïs
authors.initials: A
authors.lastname: Arbault
authors.affiliation: Service de médecine interne et maladies systémiques, hôpital du Bocage, CHU de Dijon, 21000 Dijon, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Devilliers
authors.affiliation: CIC Inserm 1432, plateforme d'investigation technologique, CHU de Dijon, 21000 Dijon, France.
authors.forename: Davy
authors.initials: D
authors.lastname: Laroche
authors.affiliation: Service de rhumatologie, hôpital du Bocage, CHU de Dijon, 14, rue Gaffarel, 21000 Dijon, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Cayot
authors.affiliation: Service de dermatologie, hôpital du Bocage, CHU de Dijon, 21000 Dijon, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Vabres
authors.affiliation: Service de rhumatologie, hôpital du Bocage, CHU de Dijon, 14, rue Gaffarel, 21000 Dijon, France; Inserm 1093, université de Bourgogne, 21000 Dijon, France.
authors.forename: Jean-Francis
authors.initials: JF
authors.lastname: Maillefert
authors.affiliation: Service de rhumatologie, hôpital du Bocage, CHU de Dijon, 14, rue Gaffarel, 21000 Dijon, France; Inserm 1093, université de Bourgogne, 21000 Dijon, France. Electronic address: paul.ornetti@chu-dijon.fr.
authors.forename: Paul
authors.initials: P
authors.lastname: Ornetti
mesh_terms: D000328:Adult; D000368:Aged; D015535:Arthritis, Psoriatic / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009262:Nails / Q000000981:diagnostic imaging*; D015588:Observer Variation; D010865:Pilot Projects; D011446:Prospective Studies; D015203:Reproducibility of Results; D013585:Synovitis / Q000000981:diagnostic imaging; D014463:Ultrasonography; D018608:Ultrasonography, Doppler
keywords: Feasibility; Nail; Psoriatic arthritis; Reliability; Ultrasonography; Validity