The sensation of a burning knee is a distinct and often alarming form of pain, suggesting irritation, inflammation, or nerve dysfunction near the joint. This symptom is not a diagnosis, but a warning signal that something is irritating the sensitive structures of the knee. Causes vary widely, ranging from simple mechanical strain and overuse to complex systemic diseases or nervous system issues. Understanding the origin of the burning feeling is the first step toward relief, as treatment for an inflamed joint differs significantly from that required for a compressed nerve.
Inflammatory Joint Conditions
A burning sensation can frequently be traced back to conditions where the knee joint or surrounding tissues are actively inflamed, which generates heat and chemical irritation. The body’s immune response releases inflammatory mediators, which sensitize local nerve endings and cause the perception of a hot or burning feeling. This reaction often results in visible swelling, warmth to the touch, and redness over the affected area.
Gout is a prime example, causing acute burning pain due to the sudden deposition of urate crystals within the joint fluid. This inflammatory arthritis is characterized by rapid onset, often occurring overnight, where the knee becomes intensely swollen. Similarly, bursitis involves the inflammation of the small, fluid-filled sacs (bursae) that cushion the knee joint, typically causing localized burning and tenderness on the front of the joint.
Systemic conditions like Rheumatoid Arthritis (RA) contribute to a burning joint by triggering an autoimmune response that attacks the synovial lining. This leads to chronic inflammation, joint swelling, and warmth, causing pain that may affect both knees symmetrically. A more serious cause is septic arthritis, a severe bacterial infection within the joint space that must be considered a medical emergency. This condition causes intense, rapidly developing pain, swelling, and burning, often accompanied by a high fever, requiring immediate hospital treatment to prevent permanent joint damage.
Nerve-Related Causes
When the burning is described as electric, tingling, or radiating, it often indicates a problem with the nerves themselves, known as neuropathic pain. This sensation arises when nerves are compressed, irritated, or damaged, causing them to misfire pain signals to the brain. The burning feeling is a direct result of this faulty signaling along the nerve pathway.
One common source of this referred pain is sciatica, which originates from the lower back when the sciatic nerve is irritated or pinched, often by a herniated disc. The resulting pain can travel down the length of the leg, manifesting as a burning or shocking sensation that is felt behind the knee or further down the leg. Peripheral neuropathy, frequently associated with conditions like diabetes, involves generalized nerve damage throughout the body that can also cause a persistent, burning discomfort in the knee area.
Nerve entrapment within the knee itself can produce localized burning. For example, the saphenous nerve or its branches can become compressed due to trauma, surgery, or swelling in the inner knee, leading to burning, numbness, or tingling. This type of nerve-related pain is distinct because it involves a structural issue with the nerve’s path, rather than requiring the joint to be swollen or hot.
Friction and Overuse Injuries
A large number of burning knee complaints are mechanical, resulting from friction and repetitive strain on the soft tissues that stabilize the joint. These overuse injuries create localized heat and irritation as structures rub against one another or are subjected to excessive tension. The repeated microtrauma leads to inflammation, which the body interprets as a burning sensation.
Patellofemoral Pain Syndrome (PFPS), often called “runner’s knee,” is a frequent cause of burning pain felt beneath or around the kneecap. This occurs when the kneecap does not track smoothly in its groove on the thigh bone, causing the underlying cartilage to rub and become irritated. Similarly, Iliotibial (IT) Band Friction Syndrome causes a burning sensation on the outside of the knee, particularly during activities like running or cycling. The iliotibial band, a thick connective tissue, becomes tight or inflamed and snaps over the bony prominence on the side of the knee joint.
Another common overuse issue is tendonitis, such as patellar tendonitis, which involves inflammation of the tendon connecting the kneecap to the shinbone. This injury, often seen in jumping sports, manifests as a burning pain in the front of the knee due to excessive stress and micro-tears in the tendon fibers. These mechanical issues are typically aggravated by specific activities like climbing stairs, squatting, or prolonged running, and they often improve with rest, as the friction and strain are temporarily eliminated.
Knowing When to See a Doctor
While many cases of burning knee pain are manageable with at-home care, certain symptoms necessitate prompt medical evaluation to prevent long-term damage or address a serious infection. If the burning pain is accompanied by a high fever, chills, or a general feeling of being unwell, this may signal a serious joint infection like septic arthritis, which requires emergency treatment. Any sudden, intense swelling, severe pain that prevents you from bearing weight, or a noticeable deformity of the joint after a trauma should also prompt an immediate visit to a healthcare facility.
For less severe symptoms, initial self-care can be attempted using the R.I.C.E. method: Rest, Ice, Compression, and Elevation. Rest involves avoiding activities that aggravate the knee, and applying ice can reduce local inflammation and burning. However, if the pain persists for more than a few days, continues to worsen despite rest, or if the knee remains warm, tender, or significantly swollen, it is prudent to schedule an appointment with a doctor. Consulting a professional is important for an accurate diagnosis, especially if the pain is disrupting daily activities or sleep.