What should you know about swelling from the knee down?

Fluid in or around the knee can track into the lower leg, particularly after an injury or inflammation. Knee osteoarthritis, bursitis, gout, a Baker's Cyst, a meniscus tear, or an ACL tear can each present with knee symptoms, but the pattern differs. Swelling that is mainly in one calf with warmth or tenderness may need urgent assessment for a blood-flow problem. Sudden swelling after a twist, fever with a hot joint, or rapidly worsening redness also changes the level of concern.

Compare both legs and note when the swelling began, whether it is increasing, and whether the skin is hot or discoloured. Rest from strenuous activity, elevate the leg comfortably, and use a cold pack wrapped in cloth for short periods after a likely minor injury. Avoid deep massage or tight compression until a clinician has considered circulation problems. Do not puncture or drain the swelling yourself. A clinician may consider joint aspiration when fluid in the knee needs testing or pressure relief.

Get urgent medical help for sudden one-sided leg swelling, calf pain with warmth or redness, chest pain, breathlessness, coughing blood, faintness, or a fast heartbeat. Seek same-day assessment for fever with a hot swollen knee, rapidly spreading redness, severe pain, or inability to bear weight. Arrange review for swelling that persists, returns, or follows an injury even without emergency signs.

Is the swelling in the joint, soft tissues, or calf? Do I need circulation testing, imaging, or fluid analysis? Should I use elevation, cooling, or compression? Which activities are safe while the cause is being clarified?