What causes knee osteoarthritis?

The smooth surfaces of the knee can become less resilient, while the underlying bone and surrounding tissues respond to altered forces. A previous ACL tear, cartilage injury, meniscus tear, fracture, or repeated joint stress can change how load passes through the knee. Age, body composition, leg alignment, muscle strength, activity demands, and inherited joint features may also contribute. There is rarely one single cause, and imaging changes do not always match the amount of pain.

Start with an assessment of pain, movement, strength, walking pattern, and daily goals. Regular low-impact movement and progressive strengthening can support function; pacing helps avoid large swings between overdoing activity and prolonged rest. Helpful options may include cycling, water exercise, mobility work, and changes to tasks that repeatedly aggravate symptoms. A clinician can tailor treatment to the joint findings and your priorities.

Arrange an appointment for persistent pain, morning stiffness, swelling, reduced walking tolerance, or symptoms that interfere with sleep or daily tasks. Seek prompt care for a hot, very swollen knee with fever, sudden inability to bear weight, or a knee that becomes locked after injury. These features can point to a problem needing a different assessment.

Which findings support osteoarthritis in my case? What strengthening and activity plan fits my knee? Could an old ligament or meniscus injury be changing joint load? What symptoms should prompt earlier review?