Presentation
Unable to walk following fall and twisting injury. ? knee fracture.
Patient Data
On the lateral horizontal beam image a fat-fluid level is seen within the supra-patella joint recess consistent with a lipohemarthrosis. This indicates that there must be an intra-articular fracture despite the fact that no fracture can be confidently identified on either the lateral or the AP image.
CT confirms the presence of a lipohemarthrosis and demonstrates a fracture of the anterior weight-bearing surface of the lateral tibial plateau which is depressed by around 2mm.
Lipohemarthrosis of the knee.
Case Discussion
An excellent example of how detecting a lipohemarthrosis on a horizontal beam lateral knee radiograph can alert the reader to the presence of a radiographically occult intra-articular fracture. In this case a significant fracture of the lateral tibial plateau is revealed upon CT evaluation.