The knee joint is surrounded by a number of fluid filled pouches, which cushion the knee and protect it from pressure application (kneeling). If such pouches are continually irritated through friction (prolonged kneeling etc.) the pouches may get inflamed and swollen and subsequently may create pain and discomfort. The pre-patella bursa is by far the most commonly affected bursa, but there are many other bursas mainly those positioned around tendon attachments which may also by exposed to increased friction. In particular, the hamstring tendons across the inner aspect of the knee may get symptomatic especially in sporting individuals.

The image shows the different bursas around the knee. The pre-patella bursa is the most commonly affected by inflammation (from Peterson & Renström 'Verletzungen im Sport' DeutscherÄrzte-Verlag Cologne 1978).

Once inflamed, kneeling is usually extremely uncomfortable. It is important for the clinician to distinguish between an inflamed bursa, which is merely swollen and an infected bursa, which is hot, red and distinctly tender on palpation. The latter represents an emergency, as pus will have accumulated under the skin requiring urgent release and the provision of antibiotic medication.

Patient suffering from bilateral pre-patella bursitis after prolonged kneeling. The situation was improved with anti-inflammatory medication and local ice application.

In recurrent and chronic cases were medication and conservative measures are exhausted injection with Triamcinolone or surgical removal of the bursa pouch may have to be considered.