Table II.
Reliability of outcome measures
| AH interval, mm | UMI ([AH interval + r]/r) | GHCC, mm | GHa, mm | SHC, mm | |
|---|---|---|---|---|---|
| Intraobserver reliability (95% CI) | 0.960 (0.952-0.968) | 0.913 (0.897-0.928) | 0.794 (0.716-0.848) | 0.924 (0.909-0.937) | 0.728 (0.663-0.781) |
| Interobserver reliability (95% CI) | 0.962 (0.954-0.969) | 0.912 (0.895-0.927) | 0.830 (0.800-0.857) | 0.924 (0.910-0.937) | 0.722 (0.649-0.780) |
| ICC overall (95% CI) | 0.961 (0.953-0.968) | 0.913 (0.896-0.927) | 0.806 (0.749-0.849) | 0.924 (0.909-0.937) | 0.726 (0.658-0.780) |
| SD | 3.0 | 0.111 | 2.6 | 5.0 | 6.5 |
| RMSpatients | 5.8 | 0.214 | 4.8 | 9.7 | 12 |
| RMSwithin observers | 2.1 | 0.0342 | 9.1 | 3.9 | 21 |
| RMSbetween observers | 0.11 | 0.0738 | 0.81 | 3.0 | 23 |
| RMSE | 0.58 | 0.0327 | 1.0 | 1.4 | 3.2 |
| SEM | 0.58 | 0.0326 | 1.1 | 1.4 | 3.4 |
| MDC | 1.6 | 0.0905 | 3.1 | 3.8 | 9.4 |
AH, acromiohumeral; UMI, upward migration index; r, radius; GHCC, glenohumeral center-to-center measurement; GHa, glenohumeral arc measurement; SHC, scapular spine–humeral head center method; ICC, intraclass correlation coefficient; CI, confidence interval; SD, standard deviation; RMS, root-mean-square; RMSE, root-mean-square error; SEM, standard error of measurement; MDC, minimal detectable change; RMSpatients, root mean square error for between-patient variance; RMSwithin observers, root mean square error between sessions; RMSbetween observers, root mean square error between observers.
The properties of the AH interval, UMI, GHCC, GHa, and SHC are presented for the entire group, comprising 280 radiographs.