What should you know about knee swelling after a fall?

Knee swelling after a fall may reflect bruising, inflammation, or an internal injury that needs assessment. The speed of swelling, your ability to walk, and symptoms such as instability or locking are useful clues.

A direct blow can irritate tissue around the kneecap, while a twist during the fall can affect ligaments or the meniscus. An ACL tear may present with swelling and a feeling that the knee gives way; a meniscus tear may present with catching or pain along the joint line. Knee bursitis can follow pressure or impact over the kneecap. A swollen knee can also have unrelated causes, including gout, osteoarthritis, or a Baker's cyst, so the fall alone does not establish the diagnosis.

A healthcare professional may examine the kneecap, check stability, and assess circulation and movement. Do not force the knee through a locked or sharply painful position.

Stop strenuous activity, protect the knee from further knocks, and rest with the leg elevated. Apply a cold pack wrapped in cloth for short intervals. Use a walking aid only if you know how to use it safely, and avoid weight-bearing if it causes marked pain or the knee feels unstable. Do not massage a rapidly swelling area or attempt to straighten a locked knee by force.

Seek urgent assessment if the knee is visibly deformed, you cannot bear weight, the foot is numb or unusually cold, or swelling appeared very quickly. A hot swollen knee with fever needs prompt medical attention. Arrange a clinical review when pain, swelling, instability, or limited movement persists after the initial injury, even if walking is possible.

Ask whether the injury suggests a ligament, meniscus, kneecap, or soft-tissue problem. Ask which weight-bearing activities are safe, whether imaging is needed, and what signs should bring you back sooner. If fluid is substantial, ask whether joint aspiration has a role.