MR imaging of meniscal contusion in the knee

OBJECTIVE: We describe focal abnormal signal of the meniscus in the knees of six patients who had a history of acute trauma to the knee. This signal abuts the articular surface of the meniscus on MR imaging but does not meet criteria for a meniscal tear or degeneration. CONCLUSION: Acute trauma to the knee may cause an abnormal signal in the meniscus that does not meet the previously described criteria for a meniscal tear or an intrasubstance degeneration. This abnormal signal could be misinterpreted as a tear because of its contact with the articular surface; this signal is seen most often in our series in the setting of an anterior cruciate ligament tear with adjacent bone contusions. We suggest that this signal may be due to a contusion of the meniscus and that the signal may resolve over time in some patients.