Bursitis is inflammation of the bursa, a sac of lubricant between ligaments and bone.
Prepatellar bursitis (Housemaids Knee) is the most common type of bursitis, and can cause fluctuating pain, tenderness and swelling in front of the patella (kneecap).
Infrapatellar bursitis (Clergymans Knee) can cause fluctuating pain, and swelling just below the patella (kneecap), either in front of (superficial) or behind (deep) the patellar ligament. This can often be caused by kneeling too much.
Bursitis can be resolved by avoiding kneeling anti-inflammatory medication or local corticosteroid injections.
If you do a job which requires regular kneeling then a padded knee support can be helpful.
Very occasionally surgical removal of the bursa is required particularly if it becomes chronically thickened or suffers from repeated infections.