Sonographic and CT findings in lipohemarthrosis

Description: A 25-year-old man presented to the emergency department because of pain and swelling of the left knee after a motorcycle accident that had occurred 2 days earlier. He had no previous significant clinical or surgical history. Clinical examination suggested the presence of joint effusion in the suprapatellar pouch, with severe pain and consequent functional deficit in the affected knee. A radiograph of the knee showed no signs of fracture. Sonographic examination requested to further evaluate the joint effusion revealed a large joint effusion consisting of two fluid-fluid levels and three distinct layers. CT of the left knee confirmed the presence of these distinct layers within the effusion, with corresponding attenuation coefficients of fat, water, and blood. The underlying oblique fracture of the tibial plateau was detected on the CT examination
Sonographic and CT findings in lipohemarthrosis. Costa DN, Cavalcanti CF, Sernik RA. AJR Am J Roentgenol. 2007 Apr;188(4):W389 Full text