What should you know about side of knee swelling and pain?

Pain after twisting, pivoting, or a sports collision may involve a meniscus tear or ACL tear, particularly when the knee catches, gives way, or swells soon afterward. A tender, localised swelling over the outside of the knee can involve a bursa. A Baker's cyst usually creates fullness behind the knee rather than at its side. Gout can cause sudden, very painful, warm swelling, while knee osteoarthritis often causes activity-related aching and stiffness.

The symptom pattern cannot identify the cause by itself. Note whether swelling is inside the joint or in one spot, whether the knee locks, and whether there was fever, injury, or a change in activity.

Reduce impact, kneeling, squatting, and twisting while the knee is swollen. Use a cold pack wrapped in cloth, elevate the leg, and keep gentle range-of-motion movements within comfort. Avoid returning to sport while the knee gives way or cannot fully bend and straighten.

A clinician can assess ligaments, menisci, the kneecap, joint fluid, and the calf. Depending on the findings, care may include rehabilitation, medication advice, imaging, or joint aspiration to examine or relieve excess fluid.

Seek urgent care for a hot, red, very painful knee with fever, sudden major swelling, a visible deformity, inability to bear weight, or a locked knee. Get prompt help for new calf swelling with breathlessness or chest pain. Arrange assessment for recurrent swelling, repeated giving way, or symptoms that do not settle with reduced loading.

Is the swelling inside the joint or in a bursa? Which structures might be injured? Do I need imaging or joint aspiration? What movements are safe, and which recovery milestones should come before sport?