What should you know about knee looks swollen?

Compare both knees in the same position and notice whether the fullness is above the kneecap, beside it, or behind it. A soft fullness can reflect joint fluid; local swelling over the kneecap may involve a bursa; fullness behind the knee can occur with a Baker's cyst. Injury-related swelling may occur with an ACL tear or meniscus tear, while knee osteoarthritis and gout can also change the shape of the joint. A visible difference does not identify the cause by itself.

Rest from impact, elevate the leg when sitting, and try a wrapped cold pack briefly if comfortable. Keep the knee gently moving within an easy range rather than holding it rigid. Take a photo in similar lighting if the change is intermittent, and note pain, heat, redness, recent exercise, and any twist or fall. A clinician can determine whether the swelling is in the joint or in nearby tissues.

Get urgent care if the knee is hot and red with fever, if swelling appeared after major trauma, or if you cannot bear weight. Seek prompt review for worsening pain, locking, repeated swelling, or a rapidly enlarging area behind the knee. Breathing difficulty or chest pain with leg swelling requires emergency help.

Ask where the swelling is located, whether an examination or imaging is needed, and whether joint aspiration has a role. Ask which activities and movements are safe while the cause is being clarified.