Pain on the inner side of your knee when bending is a common concern that can significantly impact daily activities. This discomfort can arise from various sources, including acute injuries or gradual wear and tear. Understanding these potential reasons is the first step toward effective treatment.
Medial Knee Anatomy
The knee is a complex joint composed of bones, cartilage, ligaments, and tendons. On the inner, or medial, side, several structures are relevant to pain during bending.
The medial collateral ligament (MCL) is a strong tissue band connecting the thigh bone (femur) to the shin bone (tibia), providing stability. Inside the joint, the C-shaped medial meniscus acts as a shock absorber and helps distribute weight. The bone ends are covered with smooth articular cartilage for frictionless movement.
Just below the inner knee, the pes anserine bursa cushions three hamstring tendons (sartorius, gracilis, and semitendinosus) as they attach to the shin bone.
Common Causes from Injury or Overuse
Pain on the inner knee when bending often results from specific injuries or repetitive strain. A medial collateral ligament (MCL) sprain occurs when a force impacts the outside of the knee, pushing it inward, or during twisting. This can stretch or tear the MCL, causing pain and tenderness along the inner knee, worsening with bending.
A medial meniscus tear, damage to the C-shaped cartilage, is another common cause. Tears result from acute twisting injuries, especially with a planted foot and bent knee, or develop gradually from degenerative changes. Symptoms include inner knee pain, often aggravated by bending, squatting, or twisting. Some may also experience clicking, popping, or a sensation of catching or locking.
Inflammatory and Degenerative Conditions
Beyond acute injuries, inflammation and degenerative changes also contribute to inner knee pain when bending. Pes anserine bursitis or tendinitis involves inflammation of the bursa or associated tendons below the inner knee. This condition causes pain that increases with activities like bending, climbing stairs, or rising from a chair, and can present as night pain. It is linked to overuse, obesity, and knee osteoarthritis.
Medial compartment osteoarthritis is a common degenerative condition where protective cartilage on the inner knee joint wears away. This breakdown leads to bone-on-bone friction, causing pain, stiffness, and reduced range of motion, particularly with weight-bearing activities, bending, and climbing stairs.
Medial plica syndrome occurs when a normal tissue fold (plica) in the knee lining becomes irritated or inflamed from repetitive bending. This results in pain, sometimes with a snapping or clicking sensation, and discomfort when bending or getting up after prolonged sitting. Pain felt in the knee can also sometimes originate from other areas, such as the hip or lower back.
When to Consult a Doctor
While many instances of inner knee pain can be managed with self-care, certain symptoms warrant a professional medical evaluation. You should seek medical advice if you experience severe, sudden pain or are unable to bear weight on the affected leg. Other concerning signs include sudden swelling or a visible deformity of the knee.
It is also advisable to consult a doctor if your knee is locking, catching, or giving way during movement. Persistent pain that does not improve with rest and initial self-care measures, or if you develop numbness or tingling in your leg or foot, should prompt a medical visit. Additionally, any signs of infection around the knee, such as fever, increasing redness, or warmth, require prompt attention.
What You Can Do Initially
For initial management of inner knee pain when bending, several self-care measures can provide relief. The RICE method—Rest, Ice, Compression, and Elevation—is recommended for acute injuries and inflammation.
Rest the knee by avoiding aggravating activities. Apply ice packs for 15-20 minutes, several times daily, to reduce pain and swelling. Use compression to limit swelling and elevate the leg above heart level to reduce fluid buildup.
Over-the-counter pain relievers like NSAIDs (ibuprofen or naproxen) or acetaminophen can manage pain and inflammation. Modifying activities to reduce stress, such as switching to low-impact exercises like swimming or cycling, is beneficial.
Gentle movement and stretching, if pain allows, can help prevent stiffness, but do not push through pain. These measures are for temporary relief and should not replace professional medical advice if symptoms persist or worsen.