What is prepatellar bursitis?
Prepatellar bursitis is an inflammation of a small fluid-filled sac known as the prepatellar bursa, named so because it is in front of the patellar tendon. This sac of soft tissues acts as a cushion to help reduce friction. Activity such as repetitive kneeling, multiple knee injuries, or acute trauma causes the bursa to become irritated and fill with fluid, resulting in knee pain and swelling.
There are two main types of prepatellar bursitis:
- Aseptic prepatellar bursitis: non-infectious
- Septic prepatellar bursitis: also called infectious bursitis, this often involves bacteria like Staphylococcus aureus and likely requires immediate treatment.
Those at most risk of developing prepatellar bursitis include individuals whose work involves frequent kneeling like gardeners and roofers, which is why it's called housemaid's knee (or similar variants, such as carpet-layers' knee or carpenter's knee). Other individuals at higher risk include athletes, patients with underlying conditions such as rheumatoid arthritis and gout, and immunosuppressed patients. This includes patients with diabetes mellitus, those who engage in chronic steroid use, and those undergoing hemodialysis.
Symptoms of an inflamed bursa can include localized swelling, tenderness, and restricted range of motion of knee movements. In cases of prepatellar septic bursitis, patients may experience erythema, warmth, and fever due to the presence of infection.
Diagnosis of prepatellar bursitis typically starts with a physical examination to assess localized swelling, pain, and the affected knee’s range of motion. Clinicians may palpate the area for tenderness and use imaging (e.g., X-rays or MRI) to rule out fractures or other conditions. In cases where infection is suspected, fluid aspiration and lab analysis help diagnose prepatellar bursitis, distinguishing septic from aseptic cases.










