What should you know about popliteal bursitis?

A bursa reduces friction between moving tissues. When it becomes irritated, fluid can collect and create a soft or tense feeling behind the knee. The knee may feel stiff after sitting, and bending or kneeling can increase pressure. Popliteal bursitis can occur alongside another knee problem, so the swelling itself does not identify one single cause.

A clinician may examine the front and back of the knee, compare movement, and consider whether joint swelling, arthritis, injury, or inflammation elsewhere is contributing. Imaging or fluid assessment may be suggested when the finding is unclear or infection needs to be considered.

Reduce activities that repeatedly compress or sharply bend the knee, while keeping gentle movement within comfort so the joint does not become unnecessarily stiff. Elevation and a wrapped cold pack may ease irritation; protect the skin and avoid applying cold directly. Medication choices depend on your health history and other medicines, so discuss anti-inflammatory medication with a clinician or pharmacist.

If symptoms persist, treatment may include a cortisone injection or joint aspiration in selected cases. These are clinical procedures, not home treatments, and the cause of the swelling should be considered before either is chosen.

Arrange prompt medical assessment for a hot, red, rapidly enlarging, or very painful knee, especially with fever or feeling unwell. Seek urgent help for sudden calf swelling or pain, new breathlessness, chest pain, or inability to bear weight. A painful lump behind the knee after an injury also deserves timely review.

Ask what is causing the fluid, whether an ultrasound or other test is useful, which activities to pause, and whether medication, aspiration, or injection is appropriate for you.