On ultrasound, lipohemarthrosis—the presence of blood and fat in the joint cavity—is a key clinical indicator of an intra-articular fracture.  

Lipohemarthrosis appears as three distinct layers near the joint line.  

• Superficial Layer- hyperechoic fat with circular anechoic fat globules 
• Middle Layer- Anechoic Serum 
• Deep Layer- Slightly hyperechoic, representing clotted blood 

References

Salerno A. Lipohemarthrosis. Floating fat in an intra-articular fracture. Visual Journal of Emergency Medicine. 2022, 26:101236.