Traumatic Posterolateral Corner Injury of the Knee in a Jiu-Jitsu Athlete

Multiligamentous knee injuries involving the posterolateral corner (PLC) and the posterior cruciate ligament (PCL) are uncommon but clinically significant due to their association with marked instability and functional limitation. They usually result from combined varus and rotational mechanisms, as seen in martial arts. Diagnosis relies on clinical–imaging correlation, with magnetic resonance imaging (MRI) being crucial for identifying the affected structures, including partial tears and avulsion fractures such as the “arcuate sign.” Early recognition is essential to prevent chronic instability and secondary degenerative changes. Management depends on the severity and functional demands of the patient, with surgical reconstruction recommended in combined or complete injuries. This case demonstrates the characteristic MRI findings of PCL and PLC rupture with fibular styloid avulsion in a recreational jiu-jitsu practitioner, emphasizing the value of multiplanar MRI in diagnosis and treatment planning.