Sonographic evaluation of lipohemarthrosis: clinical and in vitro study.

The purpose of this study is to evaluate the role of sonography in diagnosing lipohemarthrosis. Sonography was performed on seven patients with intra-articular fractures of the knee, shoulder, and hip. An in vitro mixture of fat and blood was examined as the gold standard. In the patients scanned a few minutes after immobilization, a two-band appearance of joint effusion was present, representing a fat-blood level. One patient scanned 3 hours after immobilization showed a three-band appearance of joint effusion, corresponding to the layers of fat, serum and red blood cells. Results of this study indicate a high reliability of ultrasonography in detecting lipohemarthrosis.