Burning knee pain is an unsettling sensation, often described as a sharp sting, tingling, or electrical shock. This discomfort suggests irritation within the joint structures or surrounding tissues. It occurs when pain receptors are intensely stimulated, or when sensory nerves are damaged or malfunctioning, sending signals interpreted as heat or fire. The cause generally falls into three main categories: nerve signaling problems, internal joint degradation, or repetitive motion friction.
Nerve Irritation and Referred Pain
A burning sensation often points directly to a problem within the nervous system, as damaged nerve fibers send faulty signals to the brain. One common cause is peripheral neuropathy, where nerves outside the brain and spinal cord are damaged, frequently seen in individuals with diabetes. Neuropathy around the knee can involve specific nerves, such as the fibular or tibial nerves, which may become irritated due to trauma, swelling, or compression.
The source of the knee pain may also originate far away from the joint itself, traveling down the leg as referred pain. Sciatica is a frequent example, where the sciatic nerve or its roots in the lumbar spine become compressed, often due to a herniated disc. The pain radiates along the nerve’s path, causing a sharp, burning sensation that extends down the leg and into the knee. When the L2-L4 nerve roots are irritated by spinal issues, the pain can even be felt in the front of the knee.
Joint Inflammation and Structural Wear
Internal issues directly within the joint capsule are another source of chronic burning pain, usually linked to inflammation and structural changes. Osteoarthritis (OA) involves the progressive thinning of cartilage that normally cushions the joint surfaces, leading to friction as bones begin to rub together. This friction causes inflammation and can result in acute flare-ups where the pain intensifies. As the condition advances, bone spurs, known as osteophytes, can form on the edges of the joint, irritating surrounding tissues and ligaments.
Inflammatory conditions caused by systemic disease can also trigger burning pain within the knee. Gout, for instance, is an inflammatory type of arthritis caused by the buildup of uric acid crystals in the joint fluid. A gout flare-up develops rapidly, causing the joint to become swollen, hot, and painful to the touch. Bursitis, the inflammation of the small fluid-filled sacs that cushion the knee joint, is another localized inflammatory cause. When a bursa becomes inflamed, the resulting pressure and localized heat can produce a burning sensation, especially with movement or direct pressure.
Overuse Injuries and Soft Tissue Friction
Mechanical problems resulting from repetitive motion and soft tissue friction outside the joint are a common cause of burning knee pain in physically active individuals. Iliotibial Band Syndrome (ITBS) is a frequent culprit, where the thick band of tissue running along the outside of the thigh becomes irritated and inflamed. This occurs because the IT band repeatedly rubs over the lateral femoral epicondyle, a bony prominence on the outside of the thigh bone, particularly when the knee is flexed at about a 30-degree angle. The resulting inflammation and friction generate a distinct aching or burning feeling, typically localized to the outer side of the knee.
The front of the knee is often affected by Patellofemoral Pain Syndrome (PFPS), commonly called Runner’s Knee, which is associated with overuse. This condition involves irritation where the kneecap, or patella, tracks over the thigh bone. Repetitive stress can lead to inflammation or softening of the cartilage beneath the kneecap, causing a burning sensation that intensifies during activities like running, climbing stairs, or prolonged sitting. Patellar Tendinitis, or Jumper’s Knee, involves inflammation of the tendon connecting the kneecap to the shinbone, which causes burning discomfort just below the kneecap due to excessive strain.
When Burning Knee Pain Requires a Doctor
While many causes of burning knee pain can be managed with rest, certain symptoms indicate a serious underlying issue requiring immediate medical attention. Sudden, severe pain that makes it impossible to bear weight suggests a possible fracture, ligament tear, or acute dislocation. Swelling, especially if the knee looks red, feels warm to the touch, or is accompanied by fever or chills, raises concern for an infection such as septic arthritis.
Any burning pain that is persistent and does not improve after a few weeks of home treatment, or pain that progressively worsens, should be evaluated by a healthcare professional. Symptoms that include a locking or catching sensation in the joint may suggest a torn meniscus or a loose body inside the joint. If the burning sensation is accompanied by numbness, tingling, or muscle weakness in the leg or foot, a neurological assessment is warranted to rule out nerve damage or spinal issues.