Medial collateral ligament avulsion

Avulsion of medial collateral ligament is seen from its tibial attachment with lax,
superiorly displaced medial collateral ligament. In the distal most part, pes anserine tendons appear deep to the superficial medial collateral ligament, the so called Stener-like lesion of superficial medial collateral ligament.

Multiple other bony, ligamentous and myofascial injuries are seen:

• subchondral compression fracture of lateral femoral condyle with surrounding marrow edema. Bone contusions with marrow edema are seen in both tibial condyles. Mild marrow edema is also seen in medial aspect of medial femoral condyle
• near complete tear of anterior cruciate ligament in mid segment with anterior translation of tibia relative to femur
• low-grade sprain of femoral attachment of lateral collateral ligament
• partial tears of popliteus tendon and myotendinous junction with possible tears of posterolateral joint capsule including popliteofibular and arcuate ligaments
• partial tears of femoral attachment of medial patello-femoral ligament
• partial undersurface tear of patellar tendon involving its attachment at tibial tuberosity with edema/minimal fluid between patellar tendon and tibial tuberosity
• avulsion of posterior horn of lateral meniscus with displacement anterosuperiorly, lying at lateral aspect of lateral femoral condyle. Displaced fragment appears in continuity with anterior horn
• edema  involving meniscocapsular junction of medial meniscus
• partial tears of vastus lateralis muscle
• moderate joint effusion seen, extending into suprapatellar recess