What knee pain is and how it varies
The knee is the most heavily loaded joint of the leg. It involves the thigh bone, shin bone, kneecap, cartilage, menisci and ligaments. Any of them, or the muscles and tendons around them, can hurt. The pain may be sharp after an injury or a dull ache for months, constant or only with movement. A diagnosis cannot be made from a text, but where and when it hurts shows what may be behind it and how urgent a visit is.
Knee pain after an injury
Pain that begins after a fall, a blow, a sharp twist or a landing may mean a bruise, a sprained or torn ligament, a meniscus tear, a dislocated kneecap or a fracture. Worrying signs are a knee that swells quickly, cannot bear weight or straighten fully, gives way or looks deformed. Get urgent care. A traumatologist treats injuries, and an orthopedist can help with lasting problems after an injury.
Knee pain when walking and on stairs
Pain that worsens with walking, climbing stairs and squatting, and eases at rest, is more often tied to worn cartilage (osteoarthritis). It shows up after 45, with extra weight and after old injuries. Morning stiffness usually passes within minutes. In young people and athletes, pain at the front, under the kneecap, often comes from overuse in running and jumping.
Knee pain with swelling, clicking or locking
Clicking without pain is usually harmless. But if the knee clicks and hurts, catches, will not straighten or snaps painfully, have it checked: that happens with damage to the meniscus or cartilage. Swelling without an injury can signal inflammation of the joint or the bursa around it.
A hot, red knee with a fever
Hot, red, very painful skin over the knee with a fever or chills may point to an infection in the joint. See a doctor the same day and do not treat it at home. Sudden sharp pain and swelling of the knee without an injury also happens with gout. For pain in other joints, see Joint pain.
Knee pain in a child or teenager
In teenagers who play a lot of sport, pain just below the kneecap that gets worse with activity can come from growing bones and tendons. But if the child limps, cannot put weight on the leg or has constant pain at night, see a pediatrician or traumatologist without waiting for it to pass.
What you can do before the visit
- Cut back on load: avoid running, jumping and deep squats, but do not lie still for weeks.
- If the knee is swollen after activity or an injury, apply ice wrapped in a cloth for about 20 minutes several times a day.
- Raise the leg when sitting or lying down.
- If you are overweight, losing weight takes load off the knees.
- Do not heat or rub a knee that is hot and red.
- Discuss the choice of painkiller with a doctor or pharmacist, especially with stomach, kidney or heart problems.
How a doctor looks for the cause
The doctor asks about injuries and activity, examines the knee, compares it with the healthy one and checks the stability of the ligaments and the range of movement. An X-ray, ultrasound, MRI and blood tests may follow, and if there is fluid in the joint, a test of that fluid. Treatment depends on the cause: exercises and physiotherapy, medicine, sometimes surgery.