What should you know about knee keeps swelling up?

Swelling soon after a twist may occur with an ACL tear or meniscus tear. Gradual swelling after activity may fit knee osteoarthritis or bursitis. A painful, hot, sudden flare can occur with gout, while fullness behind the knee can be a Baker's cyst. The timing, warmth, redness, injury, fever, and ability to bear weight help a clinician narrow the possibilities; swelling alone cannot identify one cause.

Reduce impact and kneeling, rest with the leg supported, and use a wrapped cold pack for short periods if it feels soothing. Gentle movement can limit stiffness, but do not force a swollen joint through pain. Record when swelling appears, what activity preceded it, and whether the knee feels hot or catches. A clinician may examine the joint and, when appropriate, discuss joint aspiration to analyse or relieve fluid.

Seek urgent assessment for a hot, red, rapidly swollen knee with fever or feeling unwell, or when you cannot bear weight after an injury. Prompt review is also sensible for repeated swelling, marked pain, locking, or calf swelling. Emergency help is needed if severe swelling is accompanied by breathing difficulty or chest pain.

Ask whether the swelling is inside the joint or around it, whether fluid testing or imaging is useful, and which exercises are safe. Ask how to recognise infection, a flare, or a new injury.