Isolated posterior cruciate ligament injury

The patient was a 19-year-old male cadet at a military academy who was evaluated by a physical therapist in a direct-access capacity for a chief complaint of right knee pain and giving way after falling onto his right knee while snow sledding at a high rate of speed 2 weeks earlier. Knee radiographs were ordered by the physical therapist, which demonstrated a large suprapatellar joint effusion. Due to concern for a posterior cruciate ligament injury and to assess for concomitant injury, magnetic resonance imaging was ordered, which revealed disruption of the posterior cruciate ligament without injury to surrounding tissues.