The prepatellar bursa located between the patella and the overlying skin and prepatellar tendon. It is lined by synovium and contains very little fluid. Its function is to diminish friction and ensure maximal range of motion at the knee. Chronic trauma from repeated kneeling is one cause of prepatellar bursitis, also called “housemaid’s knee”. It is common in roofers, plumbers and carpet layer.
symptoms of prepatellar bursitis include knee pain, swelling, redness and inability to flex the knee on the affected side. The symptoms are usually relieved by rest. Physical examination reveals tenderness to palpation, erythema, crepitance, and fluctuant edema over the lower pole of the paella.
Source: USMLE World 2009