Side of knee swollen after a fall: what to know

A fall can injure the tissues beside the knee, causing local puffiness, tenderness, or bruising. Swelling that feels like it is inside the joint may be an effusion. A twisting fall can also affect the meniscus or ACL; these injuries may cause catching, giving way, or swelling that develops after the event. Local swelling over the outer or inner bony side can involve a bursa. A swollen knee does not by itself identify one condition.

Notice whether the swelling is warm, whether the knee can fully bend and straighten, and whether the foot feels numb or looks unusually pale or cold. These details help a clinician decide whether examination or imaging is needed.

Reduce walking and avoid running, jumping, kneeling, and twisting while the knee is painful. Rest the leg in a comfortable position, use a cold pack wrapped in cloth for short periods, and elevate the leg when resting. Gentle movement within a comfortable range can help prevent stiffness; do not force a painful bend. A walking aid may reduce load if bearing weight hurts. Ask a pharmacist or clinician which pain medicine is suitable for you, especially if you have other medical conditions or take regular medicines.

Arrange urgent assessment if the knee looks deformed, swelling appeared rapidly, you cannot take a few steps, the knee repeatedly gives way, or you cannot move it normally. Seek immediate help for a cold or numb foot, severe worsening pain, or an open wound. Fever, spreading redness, or marked warmth also needs prompt medical review. If swelling and pain are not settling with activity reduction, book an orthopaedic or physiotherapy assessment.

Ask whether the swelling is in the joint or in the tissues beside it, whether an examination or scan is appropriate, and which movements or exercises are safe. If fluid remains troublesome, ask whether [Joint Aspiration](/treatments/non-surgical-orthopedics/joint-aspiration/) is relevant and what cause needs to be ruled out.