Injection Techniques - diagnosis of an effusion

The diagnosis of an effusion on a joint is made by taking a history, examining the joint and performing an aspiration.

History:

• intermittent or constant swelling

• trauma (rapid onset swelling over a 24 hour period suggests a haemarthrosis or a lipohaemarthrosis)

• arthritic pain of longstanding

Examination:

• Mild effusion: try to sweep the fluid from one parapatella gutter to the next

• Moderate effusion: try to espressess the fluid from the suprapatella pouch and then tap the patella onto the trochlea groove with the fingers of the other hand.

• Large effusion:  this is felt as a tense fluctuant swelling

The video clip above is demonstrating the clinical sign of a small effusion of the knee.

Learning Point: always ask about tenderness before you elicit these diagnostic clinical signs.