Anterior suprapatellar fat pad impingement syndrome

Case contributed by Domenico Nicoletti
Diagnosis certain


Intermittent anterior knee pain and swelling for approximately 6 months without any history of major trauma, fracture or infection.

Patient Data

Age: 45 years
Gender: Male

The sagittal fat-suppressed proton density images show swelling of the anterior suprapatellar fat pad with a high signal intensity while it appears hypointense on sagittal T1 weighted image.

There’s also proximal patellar tendinopathy that shows on PD fat-suppressed images as mild thickening and increased signal intensity with sparing of anterior tendon fibers.

Case Discussion

Three normal anterior knee fat pads are present at the knee which separates joint capsule and synovium; the quadriceps (anterior suprapatellar fat pad), the prefemoral (posterior suprapatellar or prefemoral fat pad) and Hoffa (infrapatellar fat pad) fat pads. The anterior suprapatellar fat pad prevents direct friction of the quadriceps tendon against the femoral condyle, during normal movement of the knee. Repetitive microtrauma or overuse injury may cause mechanical impingement resulting in edema and enlargement of the suprapatellar fat pad.

Case courtesy Dr.ssa Laura Braccaioli

Radiographer: TSRM Fabio Imola

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