My right leg is swelling from the knee down: what should I know?

A knee injury such as an ACL Tear or Meniscus Tear can cause joint fluid and nearby swelling. A Baker's Cyst is fluid from the knee that may create fullness behind the knee and sometimes swelling down the calf. Knee Bursitis usually causes more localised swelling near a bursa, while Knee Osteoarthritis can produce stiffness and fluid after activity. Gout can cause a suddenly painful, hot, red joint. Swelling that is mainly in the calf, especially with warmth, tenderness, or a noticeable difference from the other leg, needs medical assessment because not every cause is a knee disorder.

Compare both legs and note when the swelling began, whether it is worsening, and whether the skin feels hot or changes colour. Rest from impact activity, elevate the leg when comfortable, and avoid tight clothing around the calf. Do not massage a newly swollen calf until a clinician has considered circulation-related causes. Arrange prompt medical advice for unexplained one-sided swelling, especially after travel, illness, surgery, or injury. A clinician may examine the knee and calf and decide whether imaging or other tests are needed.

Seek emergency help immediately for leg swelling with chest pain, sudden breathlessness, coughing blood, faintness, or a racing heartbeat. Seek urgent assessment for a hot, red, very painful leg, fever, rapidly increasing swelling, inability to bear weight, or a pale or cold foot. These warning signs should not be managed by waiting for routine review.

Does the swelling seem to come from the knee, calf, skin, or circulation? What examination or scan is appropriate? Should I limit walking, use elevation, or avoid massage? Which changes mean I should seek emergency care?