Abstract
Abstract
Purpose
To elaborate an optimized scheme for the Dejour classification of trochlear dysplasia based on axial and sagittal MR images and to evaluate its intra- and inter-reader reliability.
Material and methods
Over a period of 20 months patients with a knee MRI and the diagnosis of trochlear dysplasia were retrospectively included. Exclusion criteria were incomplete examination, qualitatively non-diagnostic examination, post trochlear surgery, missing informed consent for research purposes. Three independent evaluations were performed by two radiologists: first using an established description of the Dejour classification (types A–D) and then two evaluations using a new adapted scheme (types A–D). The adapted scheme includes a shallow trochlea, in type A no spur/no cliff, in type B with spur/no cliff, in type C no spur/with cliff, and in type D with spur/with cliff.
Results
One hundred seventy-one knee MRIs (female:65.5%; left side:52.6%) were included with a median age of 34.3 years (range:11.3–79.2). Inter-reader reliability using the established description was fair for the four-type-classification (kappa(k) = 0.23; 95%CI:0.11–0.34), fair for differentiation low-grade versus high-grade dysplasia (k = 0.28;0.13–0.43), slight for differentiation spur versus no-spur types (k = 0.20;0.05–0.34). Inter-reader reliability using the adapted scheme was substantial (k = 0.79;0.75–0.83) for the four-type-classification, substantial for differentiation low-grade versus high-grade dysplasia (k = 0.80;0.75–0.85), substantial for differentiation spur versus no-spur presence (k = 0.76;0.71–0.81). Intra-reader reliability was almost perfect for the adapted scheme (k-values: 0.88–0.95; 95%CIs: 0.84–0.98).
Conclusion
The novel adapted scheme for Dejour classification shows an almost perfect intra-reader reliability and a substantially higher inter-reader reliability. It may become a helpful tool in the daily diagnostic work of radiologists.
Publisher
Springer Science and Business Media LLC
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