Nine observational studies were included (237 patients, 306 knees). The quality assessment suggested that studies suffered from a number of methodological limitations. Only one study provided a clear definition of the medio-patellar position evaluation. Five studies provided a clear definition of the population characteristics. Only three studies included a reference standard; all patients received both the index test and reference standard in these studies.
Seven studies assessed intra-rater reliability. Six studies reported substantial or near perfect agreement for the same rater tested at different times (ICC ranged from 0.70 to 0.99). One study reported poor to fair agreement (Kappa ranged from 0.11 to 0.35). Four studies assessed inter-rater reliability. One study reported near perfect results (ICC values of 0.91 for medial measure and 0.94 for lateral measure). The other studies reported poorer agreement (ICCs ranged from 0.02 to 0.14).
Three studies assessed agreement between clinical assessment and MRI evaluation. One study reported near perfect agreement (ICC of 0.9), one reported substantial agreement (ICC of 0.61) and one reported moderate agreement (ICC of 0.44).