prepatellar bursitis

Prepatellar bursitis is inflammation and fluid collection within the prepatellar bursa, located between the patella and the overlying subcutaneous tissue. It has been historically referred to as "housemaid's knee".

Clinical presentation

Main symptoms are anterior knee pain and swelling.

Pathology

Chronic irritation due to trauma or repetitive kneeling lead to accumulation of fluid within the prepatellar bursa and sometimes hemorrhagic transformation. Less common causes include:

Radiographic features

Plain radiograph

May show

  • prepatellar soft tissue swelling
  • clumps of calcifications in the prepatellar soft tissues in chronic cases
Ultrasound

Hypoechoic fluid, sometimes containing debris, is noted anteriorly to the patellar surface .

MRI

Oval shaped fluid-filled sac is seen anterior to the patella and displays low T1 and bright T2/STIR signal intensity. When hemorrhage occurs T1 signal increases and T2 GRE signal reduces. The wall of the bursa may show increased thickness and irregularity.

Treatment and prognosis

Local injection of non-steroid anti-inflammatory drugs and steroids or local application of ice, and finally bursectomy in resistant cases.

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