What should you know about right leg knee swelling?

Swelling soon after a twist, landing, or change of direction can occur with an ACL tear or meniscus tear. A soft fullness behind the knee may be a Baker's cyst. Swelling over the kneecap can involve knee bursitis, while gradual stiffness and activity-related discomfort may fit knee osteoarthritis. A hot, red, very tender knee can occur with gout or infection and needs prompt assessment. The amount of swelling does not by itself identify the cause; the timing, injury, range of motion, locking, and ability to bear weight are useful clues.

Reduce impact, kneeling, squatting, and twisting while the knee is swollen. Elevate the leg when resting and use a wrapped cold pack briefly if it eases discomfort. Keep gentle bending and straightening within a comfortable range so the joint does not become stiff. Do not force a locked knee or return to sport while it gives way. A clinician may assess the ligaments and meniscus; joint aspiration can sometimes remove fluid and help clarify what is happening when swelling is substantial.

Arrange prompt care if swelling follows a significant injury, the knee cannot fully move, it locks or repeatedly gives way, or you cannot bear weight. Seek urgent help for a hot red knee with fever, rapidly worsening swelling, severe pain, or a new swollen calf. After an injury, visible deformity or a foot that becomes numb, cold, or pale requires emergency assessment.

Is the fluid inside the joint or in a bursa? Could a ligament, meniscus, arthritis, gout, or cyst explain the pattern? Do I need imaging or joint aspiration? Which activities and exercises are safe while the knee settles?