Knee Pain: Causes, Diagnosis and Treatment

Knee pain can come from an injury, inflammation, irritation around the kneecap, or changes within the joint.

Pain may be felt at the front, back, inside or outside of the knee. It can be sharp after a twist, sore with repeated activity, stiff after rest, or aggravated by stairs, squatting or kneeling. Some people notice catching, clicking, giving way or difficulty fully bending and straightening the joint.

Seek urgent medical assessment after a major injury if the knee looks deformed, cannot bear weight, locks in one position, or becomes rapidly swollen. Prompt care is also needed with fever, marked warmth and redness, or severe pain with feeling unwell, because a joint infection needs quick treatment. A clinician can also assess persistent pain that limits walking or sleep.

The causes below are listed alphabetically, not by likelihood. An ACL tear can cause pain and instability after a sudden change of direction. A Baker's cyst may create pressure behind the knee. Chondromalacia patellae can irritate cartilage beneath the kneecap. Gout can trigger a sudden inflammatory attack. IT band syndrome often affects the outer knee during repetitive activity. Knee bursitis involves an irritated fluid-filled sac. Knee osteoarthritis can cause activity-related aching and stiffness. Meniscus and tendon problems can also produce pain, even when the knee looks normal.

A clinician asks when the pain began, what movement triggered it, whether the knee gives way or locks, and how it affects daily activities. They compare both knees, check tenderness, movement, strength and stability, and may assess the hip and walking pattern. X-rays can show bone and joint changes; ultrasound or MRI may be used when soft tissues require a closer view. Tests are selected according to the examination rather than automatically.

Early care may include adjusting aggravating activity, a clinician-advised pain plan and exercises that restore movement and strength. Physiotherapy can retrain movement and build support around the knee. A brace may help selected instability or load-related problems. Injections such as hyaluronic acid or PRP may be discussed for particular conditions, with benefits and limitations explained. Severe joint damage may lead to a conversation about total knee replacement; it is not a default treatment for every painful knee.

Increase exercise load gradually and include warm-up, strength and balance work. Build hip and thigh strength, vary repetitive tasks, and use footwear suited to the activity. After an injury, return to pivoting or running only when movement, strength and control have recovered. Keeping the knee moving during long periods of sitting can also reduce stiffness.

Swelling, stiffness, warmth, reduced movement, clicking, locking or a sense of instability can provide useful clues. Note whether symptoms began suddenly or gradually and whether they follow activity, rest or an injury.

Arrange an assessment if pain keeps returning, changes how you walk, or does not settle with sensible activity adjustment. Bring details about injuries, exercise changes and symptoms such as locking or swelling. A clear pattern helps the clinician choose focused treatment.