A hot knee is often a sign of inflammation. Several conditions can cause this inflammation, including arthritis, trauma, infections, and bursitis.
Causes of a Hot Knee
- Arthritis: Different types of arthritis, such as osteoarthritis and rheumatoid arthritis, can inflame the knee joint, causing heat and pain. Healthline notes that some forms of arthritis specifically cause warm joints.
- Trauma: An injury to the knee, such as a sprain, strain, or fracture, can trigger inflammation and heat.
- Infections: Infections in or around the knee joint (septic arthritis) are a serious medical concern and can lead to significant warmth, redness, and swelling. The NHS advises seeking immediate medical attention if your knee is hot, red, and accompanied by a high temperature and shivers. NHS
- Bursitis: Bursitis is inflammation of the bursae, fluid-filled sacs that cushion the knee joint. Inflammation can result in a warm, tender, and painful knee. Mayo Clinic mentions that a warm knee can be a symptom of knee bursitis.
- Other Causes: Intense exercise or other activities can temporarily cause warmth in the knee due to increased blood flow. However, persistent heat should warrant medical attention. MedicineNet lists injury and intense exercise as potential causes of knee warmth.
When to See a Doctor
Consult a doctor if:
- Your knee is hot to the touch and significantly warmer than your other knee.
- The warmth is accompanied by pain, swelling, redness, or limited range of motion.
- You have a fever or other signs of infection.
- The warmth persists despite rest and conservative treatment.
The sources cited indicate that a physical exam, medical imaging, and various blood, tissue, and joint fluid tests are used to diagnose the underlying cause of a warm knee.
