Which knee condition presents with acute anterior knee swelling and erythema in a cleaning worker?

• A. Chondromalacia patella
• B. Prepatellar bursitis
• C. Medial meniscus tear
• D. ACL tear

Answer: (B)

Acute swelling and erythema in the front of the knee from repetitive kneeling points to irritation of the prepatellar bursa, the small sac directly in front of the patella. In someone who spends long hours kneeling, like a cleaning worker, this bursa can become inflamed from blame or trauma, producing a warm, tender lump over the patella—classic prepatellar bursitis, sometimes called housemaid’s knee.

Other knee issues don’t fit this scenario as neatly. Chondromalacia patella mostly causes anterior knee pain and grinding with movement rather than a sudden, localized swelling with redness. A medial meniscus tear tends to give joint-line pain and mechanical symptoms such as locking or giving way after a twist, not a discrete anterior swelling with erythema. An ACL tear typically presents after a clear injury with rapid swelling from bleeding inside the joint and instability, rather than isolated anterior knee erythema from bursitis.