Patellar instability: the reliability of magnetic resonance imaging measurement parameters

Table 4 Inter-scan reliability of the MRI measurements for patellar instability

Measurement	ICC	95%CI	Mean difference	95%LoA	SEM	MDC₉₅
Patellar position
Angle of Fulkerson, deg	0.836	0.729~0.903	0.294	−5.071~5.659	1.918	5.315
Angle of Grelsamer, deg	0.325	0.054~0.550	−0.333	−10.591~9.924	3.674	10.184
Angle of Laurin, deg	0.723	0.559~0.832	1.020	−6.413~8.452	2.732	7.573
PTA, deg	0.897	0.828~0.940	−0.216	−3.729~3.297	1.262	3.497
LPD, mm	0.726	0.564~0.834	−0.092	−3.199~3.014	1.108	3.072
BSO, %	0.827	0.716~0.897	0.003	−0.051~0.057	0.020	0.054
CA, deg	0.380	0.128~0.588	4.118	−22.647~30.882	9.873	27.367
Trochlear dysplasia
SA, deg	0.887	0.808~0.934	0.902	−5.845~7.649	2.476	6.864
LTI, deg	0.915	0.855~0.951	−0.412	−3.811~2.987	1.242	3.443
TFA, %	0.793	0.663~0.876	−0.007	−0.157~0.143	0.054	0.149
TGD, mm	0.881	0.801~0.930	−0.127	−1.415~1.162	0.467	1.295
Patellar height
ISI	0.700	0.481~0.837	−0.019	−0.206~0.169	0.068	0.188
MISI	0.728	0.520~0.854	−0.013	−0.318~0.292	0.108	0.299
CDI	0.903	0.815~0.951	0.000	−0.113~0.113	0.040	0.111
BPI	0.820	0.671~0.906	−0.018	−0.217~0.180	0.071	0.198
PTI	0.655	0.373~0.819	0.069	−0.194~0.333	0.099	0.274

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

ISSN: 1471-2474