The Dejour classification for trochlear dysplasia shows slight interobserver and substantial intraobserver...

Area of Science:

• Orthopedic surgery
• Radiology
• Biomedical engineering

Background:

• Trochlear dysplasia is a key risk factor for recurrent patellar dislocation.
• The Dejour classification system categorizes trochlear dysplasia into four types (A-D).

Purpose of the Study:

• To assess the inter- and intraobserver reliability of the Dejour classification for trochlear dysplasia.
• To determine if the Dejour classification achieves at least moderate reliability.

Main Methods:

• A cross-sectional reliability study involving 28 examiners.
• Evaluation of 15 cases of patellofemoral instability with trochlear dysplasia using knee radiographs and MRI.
• Classification using Dejour's system across three rounds: computed radiography (CR) only, MRI only, and combined CR/MRI.
• Reliability calculated using kappa (κ) coefficient.

Main Results:

• Interobserver reliability was low across all imaging modalities (κ = 0.2 for CR, 0.13 for MRI, 0.12 for combined).
• Intraobserver reliability was moderate to substantial (κ = 0.45 for CR, 0.44 for MRI, 0.65 for combined).

Conclusions:

• The Dejour classification demonstrates slight interobserver reliability.
• Substantial intraobserver reliability suggests consistent use by individual clinicians.