LAUSR

PurposeTibial spine fractures (TSFs) are graded according to the Meyers and McKever (MM) classification system, which is based on a qualitative evaluation of plain radiographs. However, although MRI images can provide important information about these fractures, there is no MRI-based classification system. This study aims to (1) establish the intra- and inter-rater reliability of the MM system for use with radiographs, (2) propose a quantitative, MRI-based system and compare its reliability to the MM system, and (3) assess how often using the MRI-based system changes the classification and potential treatment plan as previously determined using MM.MethodsThe MRI-based system was designed with three grades based on quantitative displacement patterns of the fractured fragment and tissue entrapment. Four raters from a tertiary care center evaluated 20 fractures according to the MM and MRI-based systems. Observers graded images at two time points at least 2 weeks apart, after which we compared the intra- and inter-rater reliability of each system (using Fleiss’ kappa and weighted kappa, respectively) and assessed how often using the MRI-based system changed the fracture grade.ResultsBoth the MM and MRI-based systems exhibit fair to moderate intra- and inter-rater reliability (average kappa values ranged from 0.38 to 0.66). Use of the MRI-based system changed the fracture grade and as a result modified the treatment recommendations in 32.5% of cases: 6.9% were previously unnoticed fractures, 13.1% underwent a raise in grade, and 12.5% were graded as lower than before.ConclusionThe MRI-based system is as reliable as the MM system and provides specific, quantitative criteria for classifying fractures according to fragment displacement and tissue entrapment. The new MRI-based system potentially clarifies treatment indications for TSFs.Level of evidenceDiagnostic Study, Level II.