Clergyman's knee is a swelling below the knee, properly called infrapatellar bursitis - inflammation in the infrapatellar bursa.
Page updated June 2024 by Dr Sheila Strover (Clinical Editor)

What is the infrapatellar bursa?
A bursa is a pocket within the body tissue planes which is lubricated on its inside and facilitates movement of those tissues.
Because the knee has a wide range of movement, several bursa exist in relation to this joint, usually closely related to the areas where there is a lot of frictional movement. The infrapatellar bursa is at the front of the knee below the patella.

-
Quote from peer-reviewed paper:
"....A bursa is a fluid-filled sac meant to reduce the friction between surfaces. A bursa can be superficial when present between the skin and underlying tendon or bone...."
Citation: Jain M, Nayak M, Ansari S, Patro BP. Infrapatellar bursitis presenting as a lump. BMJ Case Rep. 2021 May 25;14(5):e243581. doi: 10.1136/bcr-2021-243581. PMID: 34035033; PMCID: PMC8154975.
-
Quote from peer-reviewed paper:
"....Infrapatellar bursae can be superficial or deep. The superficial infrapatellar bursa is located between the tibial tubercle and the overlying skin, whereas the deep infrapatellar bursa is located between the posterior aspect of the patellar tendon and the tibia.....
Citation: Chatra PS. Bursae around the knee joints. Indian J Radiol Imaging. 2012 Jan;22(1):27-30. doi: 10.4103/0971-3026.95400. PMID: 22623812; PMCID: PMC3354353.
What is bursitis?
Bursitis is inflammation within a bursa. This may occur simply because of repetitive trauma, and be sterile, or it may be septic from an infection resulting from a penetrating injury, like a splinter.
-
Quote from peer-reviewed paper:
"....Infrapatellar bursitis is more common in repetitive knee trauma, but sometimes aetiology remains elusive....The bursa with chronic inflammation may have calcification or become a solid lump losing its fluid content....
Citation: Jain M, Nayak M, Ansari S, Patro BP. Infrapatellar bursitis presenting as a lump. BMJ Case Rep. 2021 May 25;14(5):e243581. doi: 10.1136/bcr-2021-243581. PMID: 34035033; PMCID: PMC8154975.
-
Quote from peer-reviewed paper:
"....Trauma, infection, overuse, and hemorrhage are some of the common causes for inflammation. Other causes include systemic illness like collagen vascular disease and inflammatory arthropathy....
Citation: Chatra PS. Bursae around the knee joints. Indian J Radiol Imaging. 2012 Jan;22(1):27-30. doi: 10.4103/0971-3026.95400. PMID: 22623812; PMCID: PMC3354353.
Management of infrapatellar bursitis
If the bursa is not infected, then it is usually simply a matter of resting the knee and avoiding the activity that triggers pain.
Surgery may sometimes be necessary if the situation is complicated - such as a very large bursa, calcification or other complication.
-
Quote from peer-reviewed paper:
"....Open excision can be performed as a one-stage or a two-stage procedure, and endoscopy can be an alternative.....
Citation: Abdelghany M, Abdelrazak A, Raafat M, Fattouh E. An Unusually Massive Hemorrhagic Superficial Infrapatellar Bursa Excised in a One-stage Procedure: Case Report. J Orthop Case Rep. 2023 Aug;13(8):142-146. doi: 10.13107/jocr.2023.v13.i08.3850. PMID: 37654744; PMCID: PMC10465759.
<