Table 2

Interobserver reproducibility for individual radiographic features among the three observers at the first and second reading for the Osteoarthritis Research Society (OARS) and line drawing atlases. Interobserver κ coefficients were calculated for a triad among the three observers and for three pairs between two observers. The range of the κ coefficients for three pairs between two observers is shown in parentheses

OARS atlasLine drawing atlas
1st reading2nd reading1st reading2nd reading
Lateral tibiofemoral JSN2-150 0.49 (0.43–0.58)0.63 (0.54–0.78)0.56 (0.46–0.67)0.58 (0.50–0.65)
Medial tibiofemoral JSN0.65 (0.57–0.78)0.62 (0.53–0.70)0.61 (0.57–0.68)0.51 (0.37–0.73)
Lateral patellofemoral JSN0.67 (0.61–0.74)0.54 (0.45–0.61)0.68 (0.59–0.73)0.74 (0.66–0.85)
Medial patellofemoral JSN0.48 (0.38–0.57)0.54 (0.43–0.65)0.55 (0.54–0.59)0.56 (0.50–0.62)
Average JSN of four compartments0.59 (0.57–0.62)0.59 (0.50–0.66)0.65 (0.64–0.66)0.65 (0.60–0.75)
Lateral femoral osteophyte0.49 (0.46–0.51)0.45 (0.42–0.49)0.52 (0.42–0.62)0.44 (0.36–0.59)
Lateral tibial osteophyte0.60 (0.50–0.66)0.54 (0.51–0.59)0.46 (0.40–0.53)0.53 (0.48–0.59)
Medial femoral osteophyte0.52 (0.48–0.57)0.49 (0.44–0.56)0.58 (0.52–0.62)0.48 (0.43–0.59)
Medial tibial osteophyte0.50 (0.46–0.57)0.33 (0.25–0.43)0.51 (0.45–0.60)0.32 (0.22–0.44)
Lateral patellar osteophyte0.58 (0.51–0.65)0.63 (0.61–0.64)0.61 (0.56–0.70)0.57 (0.52–0.60)
Lateral trochlear osteophyte0.53 (0.46–0.59)0.47 (0.39–0.61)
Medial patellar osteophyte0.45 (0.39–0.58)0.21 (0.17–0.31)0.36 (0.23–0.47)0.24 (0.21–0.39)
Medial trochlear osteophyte0.69 (0.64–0.77)0.57 (0.54–0.58)
Average osteophyte of all sites0.52 (0.48–0.55)0.47 (0.44–0.50)0.55 (0.52–0.57)0.47 (0.43–0.57)
  • 2-150 JSN = joint space narrowing.