Analysis of Radiological Features of Lateral Femoral Impaction Fracture (LFC-IF) / Lateral Femoral Notch Sign will be performed on MRIs of consecutive patients after anterior cruciate ligament (ACL) injuries and without ACL injuries.

Two independent measurers will twicely measure the radiological features of Lateral Femoral Impaction Fracture / Lateral Femoral Notch Sign on MRIs of consecutive patients after anterior cruciate ligament (ACL) injuries and without ACL injuries. In cases without ACL injuries, radiological features of terminal sulcus (TS), a native sulcus located on the lateral femoral condyle, will be measured. Intra- and inter-rater agreements will be calculated.

The following radiological features will be assessed/ measured:

1. Presence of LFC-IF/ TS
2. LFC-IF/ TS depth
3. LFC-IF/ TS length
4. Distance from Blumensaat line to the front border of LFC-IF / TS
5. Distance from Blumensaat line to the deepest part of LFC-IF / TS
6. Distance from Blumensaat line to the rear border of LFC-IF / TS

Inclusion Criteria:

• Performed knee MRI with or without ACL tear

Exclusion Criteria:

• Osteophytes hindering assessment of LFC-IF/ TS morphology
• Morphological disturbances hindering assessment of LFC-IF/ TS morphology

Patients with knee MRI with or without ACL tear, aged 18-45 years old, all sexes, with eligibility criteria.