Subcutaneous abscess: anterior knee

Case contributed by Maulik S Patel
Diagnosis almost certain


Trauma to anterior knee resulting in skin bruise four days ago. Complaining of local pain, swelling, redness for the last 2 days.

Patient Data

Age: 26 years
Gender: Male

There is pre-patellar tendon soft tissue swelling. There is no supra-patellar effusion. Hoffa's fat pad is normal.

There is no bony abnormality.


There is a subcutaneous collection in the infrapatellar anterior knee; measuring about 40 x 40 x 10 mm. There are mobile echoes in it. There is local hypervascularity.

  • quadriceps tendon: intact with normal echopatten    
  • patellar tendon: intact with normal echopatten 
  • Hoffa’s fat pad: normal
  • suprapatellar bursa: no effusion

Case Discussion

Ultrasound findings of an anterior knee subcutaneous abscess following trauma. Surgery revealed pus.

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