Imaging of the anterior cruciate ligament

Figure 11 Patellar buckling sign and lateral femoral notch sign. A 37-year-old man who suffered knee injury. Osteochondral injury and patellar buckling sign. Sagittal intermediate-weighted magnetic resonance image demonstrates a deep depression of the middle portion of the lateral femoral condyle (curved white arrow). Normal condylopatellar sulcus should be smaller than 1.5 mm. Notch depth between 1 and 2 mm is suggestive and over 2 mm is diagnostic of anterior cruciate ligament tear. Buckling of proximal patellar tendon (white arrow) also indicates the underlying anterior cruciate ligament tear.