PURPOSE: The purpose of this study was to evaluate the interrater reliability of several common radiologic parameters used for patellofemoral instability, and to attempt to improve reliability for measurements demonstrating unacceptable interrater reliability through consensus training.METHODS: Fifty patients with patellar instability between the ages of 10 and 19 were selected from a prospectively enrolled cohort. For measurements demonstrating unacceptable interrater reliability (ICC<0.6), raters discussed consensus methods to improve reliability and reexamined a subset of 20 images from the previous set of images. If reliability was still low after the second round of assessment, the measure was considered unreliable.RESULTS: Of the 50 included subjects, 22 (44%) were male and the mean age at the time of imaging was 14±2 years. With one or fewer consensus training sessions, the interrater reliability of the following xray indices were found to be reliable: trochlea crossing sign (ICC:0.625), congruence angle (ICC:0.768), Caton-Deshamps index (ICC:0.644), lateral patellofemoral angle (ICC:0.768), and mechanical axis deviation on hip-to-ankle alignment radiographs (ICC:0.665-0.777). Reliable MRI indices were: trochlear depth (ICC:0.743), trochlear bump (ICC:0.861), sulcus angle (ICC:0.684), patellar tilt (ICC:0.841), TT-TG (ICC:0.706), effusion (ICC:0.866), and bone marrow edema (ICC:0.961).CONCLUSIONS: With one or fewer consensus training sessions, the interrater reliability of the following patellofemoral indices were found to be reliable for trochlear morphology: trochlea crossing sign and congruence angle on XR and trochlear depth, trochlear bump, and sulcus angle on MRI. Reliable patellar position measurements included: Caton-Deshamps index and lateral patellofemoral angle on XR and patellar tilt and TT-TG on MRI. Additional global measurements and MRI assessments demonstrated acceptable reliability.LEVEL OF EVIDENCE: 2, Prospective Diagnostic Study.
View details for DOI 10.1016/j.arthro.2022.03.033
View details for PubMedID 35398485