A novel adapted MRI-based scheme for Dejour classification of trochlear dysplasia

• DOI: 10.1007/s00256-024-04748-7
• Publication Date: 2024-07-23T08:01:50Z
• Authors: Ni Jian-Lüssi; Christian W. A. P...; Florian M. Buck; Thomas Frauenfelder; Andrea B. Rosskopf
• Keywords: 03 medical and health sciences; 0302 clinical medicine; 10042 Clinic for Diagnostic and Interventional Radiology; Trochlear dysplasia; 2741 Radiology, Nuclear Medicine and Imaging; 610 Medicine & health; Knee; Scientific Article; Classification; Dejour; MRI

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.