Burning pain on the inside of the knee is a distinct discomfort. This sensation often points to irritation or damage within structures located on the medial, or inner, aspect of the knee joint. Understanding this symptom helps identify potential causes and guides appropriate steps toward relief.
Key Anatomical Structures of the Inner Knee
The inner knee region comprises several important anatomical components. The medial collateral ligament (MCL) is a broad, flat band of connective tissue on the inner side of the knee, connecting the thigh bone (femur) to the shin bone (tibia) and resisting inward bending forces. The medial meniscus is a crescent-shaped piece of cartilage between the thigh and shin bones, acting as a shock absorber and distributing weight across the joint.
Below the inner knee joint, the pes anserine bursa is a fluid-filled sac that cushions the conjoined tendons of three muscles—the sartorius, gracilis, and semitendinosus—where they attach to the shin bone. This bursa helps reduce friction during movement. The saphenous nerve, a sensory nerve branching from the femoral nerve, travels along the inner thigh and knee, providing sensation to the skin in this area and extending down the lower leg.
Orthopedic Causes of Inner Knee Burning Pain
Several orthopedic conditions can lead to burning pain on the inside of the knee, often due to inflammation or mechanical irritation.
Medial collateral ligament (MCL) injuries, ranging from a stretch to a complete tear, typically result from a forceful impact to the outside of the knee. These injuries cause pain, tenderness, and sometimes swelling along the inner side of the knee, with burning often stemming from associated inflammation.
Pes anserine bursitis or tendinitis involves inflammation of the bursa or the sartorius, gracilis, and semitendinosus tendons. This condition often presents as pain and tenderness on the inner side, below the knee joint line. Overuse, repetitive motions, or direct trauma can cause this inflammation, leading to a burning or aching sensation.
Tears in the medial meniscus can also cause burning pain, localized discomfort, and sometimes a feeling of the knee catching or locking. The medial meniscus is susceptible to tears from twisting injuries or sudden forceful movements. Inflammation from the tear can contribute to the burning sensation.
Osteoarthritis occurs when the protective cartilage on the ends of the bones wears down. This degeneration can lead to inflammation within the joint, causing pain that may be perceived as a burning sensation. The pain can be persistent and may worsen with activity.
Nerve-Related Causes of Inner Knee Burning Pain
Nerve irritation or entrapment can specifically manifest as burning pain. The saphenous nerve, a purely sensory nerve, is a common source of such pain when compressed or irritated along its path near the inner knee. This condition, known as saphenous neuritis or saphenous nerve entrapment, can result in burning, tingling, or numbness in the inner knee, lower leg, and sometimes the foot.
The saphenous nerve can become compressed by surrounding tissues. Trauma, repetitive movements, or surgical scarring can lead to its irritation. Unlike muscle or joint pain, saphenous nerve pain often has a neuropathic quality, described as shooting or electrical, and may worsen with activity.
When to Seek Medical Attention
Consult a healthcare provider if inner knee burning pain is severe, persistent, or interferes with daily activities or sleep. Seek medical evaluation if pain does not improve with rest and at-home care.
Immediate medical attention is necessary if the pain is accompanied by significant swelling, redness, or warmth around the joint, as these could indicate inflammation or infection. Other red flags include an inability to bear weight on the affected leg, a visible deformity of the knee, or if a “popping” sound was heard at the time of injury. Also, consult a doctor if the burning pain is accompanied by numbness, tingling, or a feeling of the knee “giving out.”