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Table 2 Intra-observer reliability of the MRI measurements for patellar instability

From: Patellar instability: the reliability of magnetic resonance imaging measurement parameters

Measurement ICC 95%CI Mean difference 95%LoA SEM MDC95
Patellar position
 Angle of Fulkerson, deg 0.969 0.953~0.979 0.216 −2.019~2.450 0.808 2.240
 Angle of Grelsamer, deg 0.938 0.910~0.958 0.000 − 3.096~3.096 1.111 3.080
 Angle of Laurin, deg 0.945 0.919~0.962 −0.039 −3.325~3.247 1.175 3.257
 PTA, deg 0.953 0.931~0.968 0.069 −2.276~2.413 0.841 2.330
 LPD, mm 0.980 0.970~0.987 −0.085 − 0.899~0.728 0.298 0.825
 BSO, % 0.898 0.852~0.930 −0.005 − 0.047~0.038 0.015 0.043
 CA, deg 0.908 0.866~0.937 −0.892 −11.037~9.253 3.685 10.215
Trochlear dysplasia
 SA, deg 0.964 0.947~0.975 0.098 −3.798~3.994 1.390 3.852
 LTI, deg 0.940 0.912~0.960 −0.324 −3.152~2.505 1.040 2.883
 TFA, % 0.881 0.830~0.918 0.008 −0.103~0.119 0.040 0.112
 TGD, mm 0.940 0.913~0.959 −0.012 −0.937~0.912 0.331 0.919
Patellar height
 ISI 0.876 0.807~0.922 −0.009 − 0.128~0.111 0.043 0.119
 MISI 0.911 0.859~0.944 −0.018 −0.187~0.152 0.062 0.171
 CDI 0.917 0.869~0.948 −0.007 − 0.107~0.092 0.036 0.100
 BPI 0.851 0.769~0.905 0.005 − 0.166~0.177 0.061 0.169
 PTI 0.960 0.936~0.975 −0.005 −0.088~0.103 0.034 0.093
  1. ICC Intraclass correlation coefficient, LoA Limits of agreement, CI Confidence interval, SEM Standard error of measure, MDC95 Minimal detectable change at 95% confidence level, deg degree