### 📋 50. Ballotable Patella (Patellar Tap Test) (HTML Page Code) ````html

Patellar Tap Test (Ballotable Patella): How to Check for Swelling

The Patellar Tap Test, also known as the Ballotable Patella Test, is a quick and reliable clinical test used to detect moderate to large amounts of fluid (effusion) inside the knee joint.

1. Purpose

The primary purpose of the Patellar Tap Test (also known as the Ballotable Patella Test) is to **detect** the presence of a moderate to large joint effusion (excess fluid or swelling) within the knee joint capsule.

2. How to Perform

1. The patient is positioned in supine (lying on their back) with the knee extended or slightly flexed.
2. The examiner places one hand superior to the patella and compresses the suprapatellar pouch, pushing any fluid downwards towards the knee.
3. The examiner maintains this compression.
4. With the other hand, the examiner uses two or three fingers to quickly and firmly push (tap) the patella downwards against the femur.

3. Positive & Negative Sign

Positive Sign (Test is POSITIVE):
A positive test (indicating joint effusion) is:

• The patella is felt to "float" and bounce back up after being pushed down (ballottement).
• A distinct "tap" or click is felt as the patella hits the femoral condyles through the fluid.

Negative Sign (Test is NEGATIVE):
A negative test is when the patella does not float or bounce; it rests firmly against the femur.