Anterior suprapatellar fat pad impingement syndrome

Last revised by Mostafa El-Feky on 11 Aug 2022

Anterior suprapatellar (quadriceps) fat pad impingement syndrome is a controversial cause of anterior knee pain although anterior suprapatellar fat pad edema may often, and possibly more commonly, be incidental 1,2

Patients present with anterior knee pain and with the point of tenderness at the superior pole of the patella. The pain is exacerbated on deep knee flexion.

The etiology is unclear. It is suggested to result from repeated microtrauma resulting in fibrosis and hemorrhage. There is no significant correlation with patellofemoral maltracking 8. A recent study reported an association with patellofemoral joint degeneration 9.

The anterior suprapatellar fat pad is edematous compared to the prefemoral fat pad, enlarged (≥10 mm AP diameter) with a mass effect on the adjacent suprapatellar recess (i.e. a convex border) and quadriceps tendon 1-4.  

  • T1: low signal
  • T2: high signal
  • T1C+: enhancement

The most common associated MRI findings are joint effusion and quadriceps tendinitis 11.

Initial management is usually conservative, like anti-inflammatory medications and decreased painful activities. Complete pain resolution can be achieved with ultrasound-guided injection of anesthetic or corticosteroid followed by physical therapy 6. Surgery could be considered in cases with persistent symptoms by laparoscopic resection 7.

In the absence of anterior knee pain, quadriceps fat pad edema diagnosis cannot be made based solely on MRI findings 2,10.

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Case 2
    Drag here to reorder.
  • Case 3
    Drag here to reorder.
  • Case 4
    Drag here to reorder.
  • Case 5
    Drag here to reorder.
  • Case 6
    Drag here to reorder.
  • Case 7
    Drag here to reorder.
  • Case 8
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.