Presentation
Fall and left shoulder pain.
Patient Data
This AP xray of the left shoulder shows a transverse fracture of the surgical neck of the humerus with impaction of fragments. There is inferior displacement of the humeral head on the glenoid. This appearance (pseudosubluxation) is commonly seen in association with fracture and suggests joint effusion. There is a fat-fluid level consistent with a lipohemarthrosis. This indicates the presence of intraarticular injury.
Case Discussion
Lipohemarthrosis seen on plain radiographs is unusual in the glenohumeral joint, although in one series it was seen in 25% of cases. It was first reported in 1962 (compare with 1929 for knee lipohemarthrosis). It is only seen on erect views. Lipohemarthroses have also been described in elbow and hip joints.
Note that a fluid-fluid level may be seen in a simple hemarthrosis on MRI. The upper fluid must show magnetic characteristics of fat (e.g. drop signal on fat-sat sequences) before you can call it a lipohemarthrosis.
Image and description courtesy of: Dr Laughlin Dawes