Table 4.

Intrarater reliability and agreement on ultrasound findings* assessed with 4–6 weeks of interval by operator A

Ultrasound finding	Observed agreement (%)	Expected agreement (%)	Kappa (95% CI)	ICC (95% CI)
Joint recess profile	93	78	0.70 (0.47 to 0.86)
Bone-capsule distance (including capsule)	100	88		0.99 (0.98 to 0.99)
Bone-capsule distance (excluding capsule)	100	88		0.99 (0.99 to 0.99)
Overall joint effusion/synovitis	96	67	0.87 (0.74 to 0.99)
Femoral osteophytes	95	75	0.81 (0.72 to 0.88)
Femoral cartilage thickness†	99	93		0.93 (0.88 to 0.95)

*Only the listed findings were assessed a second time, since we found that the other findings required dynamic evaluation in order to be properly assessed.

†n=65 hips, due to exclusion of 27 hips with pronounced irregular articular cartilage.

ICC, interclass correlation coefficient.