Pre-patellar Bursitis
Housemaid's Knee

General Considerations

• Prepatellar bursa is superficial bursa
• Thin synovial lining
• Located between skin and patella
• Main function is to separate patella from patellar tendon and skin
• Normally does not communicate with joint
• Contains minimal amount of fluid
• Inflammation of prepatellar bursa results in marked increase of fluid in bursa
• Incidence of prepatellar bursitis greater in males than females

Causes

• Direct trauma (eg, a fall on patella or direct blow to knee)
• If acute, frequently due to small blood vessel rupture
• Repetitive minor injuries (eg, repeated kneeling)
• Septic or pyogenic process
• Infection usually from Staphylococcus aureus from break in skin
• More prevalent in children
• Can be mistaken for pyogenic arthritis
• Crystal deposition (eg, gout, pseudogout)
• Occupation
• Carpet layer
• Wrestlers
• Coal miner
• Roofer
• Plumber
• Homemaker (housemaid's knee)

Clinical findings

• Knee pain
• Swelling
• Redness
• Difficulty walking
• Relief of pain with rest
• History of repetitive motion
• History of occupation requiring excessive kneeling
• History of a fall on knee or blunt trauma to knee

Physical findings

• Patella tender to palpation
• Fluctuance over lower pole of patella
• Erythema
• Crepitation
• Decreased ROM

Imaging Studies

• Plain radiographs
• Soft tissue swelling
• Calcification
• Especially if hemorrhage into bursa
• Computed tomography (CT) scan and magnetic resonance imaging (MRI)
• Complex fluid collection anterior to knee in region of prepatellar bursa
• Wall of bursa my be thickened and irregular

Treatment

• NSAIDs
• Cortisone injection
• Aspiration of bursa
• Surgical removal of bursa
• Kneepad
• Has high recurrence rate 

 
Prepatellar Bursitis. Frontal and lateral radiographs of both knees demonstrate multiple, punctate calcifications in the pre- and infrapatellar regions.

Kelly Allen, MD   eMedicine.com