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Knee & Sports

Prepatellar Bursitis: swelling on the front of the kneecap.

Prepatellar bursitis is swelling of the sac in front of the kneecap, often from kneeling or a direct blow. Most cases settle without surgery, but an infected bursa needs prompt treatment.

Written bySteven J. Lee, MD · Double Fellowship-Trained · Hand & Sports Medicine
Last reviewed · May 2026

The prepatellar bursa is a thin sac between the skin and the front of the kneecap. Repeated kneeling or a direct blow can irritate it and fill it with fluid, producing a soft, swollen bump on the front of the knee, sometimes called housemaid's knee.

Most prepatellar bursitis is irritation that settles with simple measures. The important exception is an infected bursa, which is red, warm, and tender and needs prompt treatment to avoid spreading.

Symptoms

Common findings include:

  • A soft, swollen bump on the front of the kneecap
  • Pain with kneeling or pressure on the front of the knee
  • Limited bending when the swelling is large
  • Redness, warmth, and fever if the bursa is infected

When to act quickly

A bursa that is red, hot, very tender, or accompanied by fever may be infected (septic bursitis). That needs prompt evaluation, often with aspiration to test the fluid and antibiotics, and sometimes drainage. Distinguishing infected from simply irritated is the key first step.

Dr. Lee's approach

For a non-infected, irritated bursa, Dr. Lee uses activity modification (especially avoiding kneeling), padding, anti-inflammatory measures, and sometimes aspiration of the fluid. Most settle without surgery.

When infection is suspected, the fluid is tested and treated with antibiotics, with drainage if needed. Surgical removal of the bursa is reserved for chronic, recurrent cases that do not respond to these measures.

Non-surgical treatment

Most irritated bursae respond to:

  • Avoiding kneeling and using knee padding
  • Anti-inflammatory measures and ice
  • Aspiration of the fluid in selected cases

Infection and recurrence

A suspected infected bursa is aspirated, tested, and treated with antibiotics, with drainage when needed. For chronic or repeatedly recurrent bursitis that does not settle, surgical removal of the bursa is an option.

Recovery timeline

Recovery is usually quick for an irritated bursa:

  1. Weeks 0 to 3
    Avoid kneeling, use padding, and apply anti-inflammatory measures. Swelling subsides gradually.
  2. If infected
    Antibiotics and close follow-up, with drainage if the infection does not settle promptly.

What patients commonly misunderstand

The one thing not to miss:

  • Most are not infected. The majority of prepatellar bursitis is simple irritation that settles with padding and avoiding kneeling. But a red, hot, tender bursa needs prompt evaluation for infection.
  • Repeated kneeling is the usual culprit. Occupations and activities that involve frequent kneeling are the classic cause. Padding and avoiding kneeling are both treatment and prevention.

This page is general educational content authored by Dr. Lee. It is not a substitute for individual medical advice. Every patient's case is different, book a consultation to discuss yours.

Patient questions

Prepatellar bursitis, answered.

  • What causes the swelling on the front of my knee?

    It is usually fluid in the prepatellar bursa, the sac in front of the kneecap, from repeated kneeling or a direct blow. It produces a soft, swollen bump. Most cases are simple irritation, but a bursa that is red, hot, and very tender may be infected and needs prompt attention.

  • Do I need surgery?

    Almost never. Non-infected bursitis settles with avoiding kneeling, padding, anti-inflammatory measures, and sometimes aspiration. An infected bursa is treated with antibiotics and drainage if needed. Surgical removal is reserved for chronic, recurrent cases.

Next step

Soft, swollen bump on the kneecap? Usually simple, occasionally urgent.

Most prepatellar bursitis is simple irritation that settles with padding and avoiding kneeling. The one thing to act on quickly is a red, hot, tender bursa, which may be infected. The evaluation sorts out which one you have.