Applicability of Semi-Quantitative Evaluation of the Intercondylar Notch

The intercondylar notch (IN) can differ in morphology and size, influencing the contained ligaments. For a better understanding of the influence of the IN’s anatomy on knee pathologies, a classification of different shapes was proposed. However, a detailed evaluation of the reliability of these classifications is lacking thus far. In coronal knee MRIs of 330 patients, the IN width was measured and three shapes were calculated to generate objective control results. Notch shapes were classified by two blinded investigators, first without and then with visual assistance to guide the shape classification. The distribution of the three different shapes was as follows: A-shape: n = 43, 13.0%; inverse U-shape: n = 100, 30.3%; Ω-shape: n = 183, 56.7%. The semi-quantitative evaluation distribution was as follows: A-shape: n = 44, 13.3%; inverse U-shape: n = 37, 11.2%; Ω-shape: n = 249, 75%; there was fair (κ = 0.35) agreement compared to that of the control results. The assisted semi-quantitative evaluation distribution was as follows: A-shape: n = 44, 13.3%; inverse U-shape: 103, 31.2%; Ω-shape: n = 183, 55.3%; there was very good (κ = 0.92) agreement compared to that of the control results. In the shape evaluation of the IN, rigid guidelines and visual assistance must be used to ensure reliability. The utilization of visual assistance led to higher inter- and intra-rater agreements in the semi-quantitatively evaluation of the IN shape when compared to those in the classification without visual assistance.