What is a grade of 3+ on the Brush/Stroke Test?

• A. No wave produced on downstroke
• B. Small wave on medial side with downstroke
• C. Larger bulge on medial side with downstroke
• D. So much fluid that it is not possible to move the effusion out of the medial aspect of the knee

Answer: (D)

The Brush/Stroke Test assesses knee effusion by milking fluid within the suprapatellar pouch toward the medial side and watching for a wave or bulge. The grading reflects how much fluid is present.

A grade of 3+ means there is so much joint fluid that you cannot move the effusion out of the medial aspect of the knee; the pouch is full enough that the fluid stays and you don’t observe a distinct wave or bulge. This level indicates a large intra-articular effusion, often seen with significant inflammation or injury.

The smaller grades represent progressively less fluid: a tiny medial wave on downstroke for a small effusion, and a larger bulge for a moderate amount.