The frontal knee x-ray shows avulsion fracture of the tibial spine and a small flake avulsion fracture on the medial aspect of the medial femoral condyle.

The lateral knee x-ray shows significant knee effusion.

MRI scan of the knee showed avulsion at the tibial attachment of the ACL and minimally displaced osseous avulsion  of the deep fibres of MCL.

ACL attaches proximally at the posteromedial margin of the lateral femoral condyle in the intercondylar fossa and distally at the anterior aspect of the tibial intercondylar eminence.

Reference: Grainger & Allison’s Diagnostic Radiology, Sixth Edition.