title: Validity of radiographic assessment of the knee joint space using automatic image analysis.
abstract: OBJECTIVE
  The present study investigated whether there were differences between automatic and manual measurements of the minimum joint space width (mJSW) on knee radiographs.
  
  
  METHODS
  Knee radiographs of 324 participants in a systematic health screening were analyzed using the following three methods: manual measurement of film-based radiographs (Manual), manual measurement of digitized radiographs (Digital), and automatic measurement of digitized radiographs (Auto). The mean mJSWs on the medial and lateral sides of the knees were determined using each method, and measurement reliability was evaluated using intra-class correlation coefficients. Measurement errors were compared between normal knees and knees with radiographic osteoarthritis.
  
  
  RESULTS
  All three methods demonstrated good reliability, although the reliability was slightly lower with the Manual method than with the other methods. On the medial and lateral sides of the knees, the mJSWs were the largest in the Manual method and the smallest in the Auto method. The measurement errors of each method were significantly larger for normal knees than for radiographic osteoarthritis knees.
  
  
  CONCLUSIONS
  The mJSW measurements are more accurate and reliable with the Auto method than with the Manual or Digital method, especially for normal knees. Therefore, the Auto method is ideal for the assessment of the knee joint space.
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Daigo
authors.initials: D
authors.lastname: Komatsu
authors.affiliation: b Department of Hip and Knee Reconstructive Surgery , Nagoya University Graduate School of Medicine , Aichi , Japan.
authors.forename: Yukiharu
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Kojima
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Seki
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Ikeuchi
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Takegami
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Amano
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Higuchi
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Kasai
authors.affiliation: a Department of Orthopedic Surgery and.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging*; D011859:Radiography; D015203:Reproducibility of Results
keywords: Auto measurement; Diagnosis; Knee; Measurement error; Osteoarthritis; Plain radiograph