Lipohaemarthrosis in knee trauma: an experience of 907 cases.

The role of the horizontal beam lateral radiograph in the investigation of knee trauma was assessed by retrospective analysis of 907 cases presenting to a tertiary trauma unit. For each case the presence of a visible lipohaemarthrosis on the horizontal beam radiograph was correlated with the presence of an intra-articular fracture. Visible lipohaemarthrosis is a very specific sign of an intra-articular fracture (88.6 per cent), occurring in 27.1 per cent of cases. The authors propose that the horizontal beam lateral radiograph should be the standard lateral view in the investigation of knee trauma. The presence of a visible lipohaemarthrosis in the absence of a visible fracture, or isolated fracture of patella or fibula on the plain radiographs, are indications for further investigation.