Prepatellar Bursitis

There's a small fluid-filled cushion (a bursa) sitting right between the skin and the front of your kneecap. When that cushion gets irritated and fills with fluid, the front of the knee balloons out into a soft, sometimes painful swelling — that's prepatellar bursitis. The classic triggers: hours of kneeling at work (giving it the nicknames plumber's knee and carpet layer's knee), a direct hit to the front of the knee, a gout flare, or an infection working its way in. If it's infected (septic bursitis), it needs antibiotics and sometimes urgent drainage — a different problem from the everyday irritation kind.

• Soft swelling on the front of the kneecap — a visible, squishy lump right over the kneecap that may appear quickly after a bump or slowly from repeated kneeling.
• Pain with kneeling — putting your knee on the ground sends a sharp ache through the front of the knee.
• Warmth and redness — the skin over the kneecap feels hot and looks red, especially if infection or gout is the cause.
• Normal knee bending — because the bursa sits outside the joint, you can usually bend and straighten your knee without trouble.
• Fever or spreading redness (if infected) — a septic bursa may come with fever, chills, and redness that spreads beyond the kneecap — this needs urgent care.

Soft, visible swelling sitting right on top of the kneecap. Because the bursa is outside the joint itself, you can usually still bend and straighten your knee fine. To figure out which kind you have, your provider draws a small amount of fluid from the swelling with a needle (aspiration) and sends it to the lab — the cells, crystals, and culture results tell us whether it's an infection, a gout flare, or just inflammation. An MRI is reserved for cases where we want to rule out other front-of-knee problems.

1. Corticosteroid injection

   If aspiration alone doesn't keep the bursa from refilling, a steroid shot into the bursa right after draining it cuts down the chance of it coming back — but only when infection and gout crystals have been ruled out.

2. Antibiotics

   Septic (infected) bursitis is treated with antibiotics — by IV in the hospital if it's serious, or by mouth if it's milder. If it doesn't clear, surgical drainage in the OR is the next step.

Surgery (bursectomy — removing the bursa entirely) is reserved for two stubborn cases: an infected bursa that won't clear with antibiotics and drainage, or a chronic one that keeps refilling no matter how many times it's drained or injected.

External patient-education references and related OSI pages for additional background:

• Britannica — Bursitis
• Britannica — Knee (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language