title: Validity of joint space width measurements in hand osteoarthritis.
abstract: OBJECTIVE
  To investigate the validity of joint space width (JSW) measurements in millimeters (mm) in hand osteoarthritis (OA) patients by comparison to controls, grading of joint space narrowing (JSN), and clinical features.
  
  
  METHODS
  Hand radiographs of 235 hand OA patients (mean age 65 years, 83% women) and 471 controls were used. JSW was measured with semi-automated image analysis software in the distal, proximal interphalangeal and metacarpal joints (DIPJs, PIPJs and MCPJs). JSN (grade 0-3) was assessed using the osteoarthritis research society international (OARSI) atlas. Associations between the two methods and clinical determinants (presence of pain, nodes and/or erosions, decreased mobility) were assessed using Generalized Estimating Equations with adjustments for age, sex, body mass index (BMI) and mean width of proximal phalanx.
  
  
  RESULTS
  JSW was measured in 5631 joints with a mean JSW of 0.98 mm (standard deviation (SD) 0.21), being the smallest for DIPJs (0.70 (SD 0.25)) and largest for MCPJs (1.40 (SD 0.25)). The JSN=0 group had a mean JSW of 1.28 mm (SD 0.34), the JSN=3 group 0.17 mm (SD 0.23). Controls had larger JSW than hand OA patients (P-value<0.001). In hand OA, females had smaller JSW than men (β -0.08, (95% confidence interval (95% CI) -0.15 to -0.01)) and lower JSW was associated with the presence of pain, nodes, erosions and decreased mobility (adjusted β -0.21 (95% CI -0.27, -0.16), -0.37 (-0.40, -0.34), -0.61 (-0.68, -0.54) and -0.46 (-0.68, -0.24) respectively). These associations were similar for JSN in grades.
  
  
  CONCLUSIONS
  In hand OA the quantitative JSW measurement is a valid method to measure joint space and shows a good relation with clinical features.
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands. w.y.kwok@lumc.nl
authors.forename: W Y
authors.initials: WY
authors.lastname: Kwok
authors.forename: J
authors.initials: J
authors.lastname: Bijsterbosch
authors.forename: S H
authors.initials: SH
authors.lastname: Malm
authors.forename: N R
authors.initials: NR
authors.lastname: Biermasz
authors.forename: K
authors.initials: K
authors.lastname: Huetink
authors.forename: R G
authors.initials: RG
authors.lastname: Nelissen
authors.forename: I
authors.initials: I
authors.lastname: Meulenbelt
authors.forename: T W J
authors.initials: TW
authors.lastname: Huizinga
authors.forename: R
authors.initials: R
authors.lastname: van 't Klooster
authors.forename: B C
authors.initials: BC
authors.lastname: Stoel
authors.forename: M
authors.initials: M
authors.lastname: Kloppenburg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D054850:Osteophyte / Q000209:etiology; D010146:Pain / Q000209:etiology; D011859:Radiography; D015203:Reproducibility of Results