Knee pain when bending is a common experience, ranging from a mild ache to sharp, debilitating pain. Understanding its underlying causes is key to managing symptoms and improving knee function.
Understanding Specific Causes
Pain when bending the knee can stem from several distinct conditions, each affecting different structures within the complex knee joint. These conditions often involve irritation or damage to cartilage, tendons, or fluid-filled sacs surrounding the kneecap.
Patellofemoral Pain Syndrome (PFPS), frequently called “runner’s knee,” causes pain under or around the kneecap. This condition arises when the kneecap does not track smoothly in its groove on the thigh bone during knee movement. Activities like squatting, climbing stairs, or sitting with bent knees for extended periods worsen the dull, aching pain. Overuse, muscle imbalances, or direct injury to the kneecap can contribute to its development.
Osteoarthritis (OA) is a degenerative joint disease characterized by the gradual breakdown of cartilage, which cushions bones. As this cartilage wears away, bones can rub against each other, causing pain, stiffness, and swelling. Bending the knee, especially after periods of inactivity, can be particularly painful due to reduced cushioning and inflammation. This condition often affects individuals over 50.
A meniscus tear involves damage to the C-shaped cartilage pads in the knee joint. These tears often occur with sudden twisting movements, such as during sports. Symptoms include pain, stiffness, and swelling, with difficulty bending or straightening the knee. A sensation of the knee “giving way,” locking, or catching, sometimes accompanied by a crunching or clicking sound, may also indicate a meniscus tear.
Tendinopathy refers to the inflammation or degeneration of tendons, the fibrous cords connecting muscles to bones. Patellar tendinopathy, sometimes called “jumper’s knee,” affects the patellar tendon below the kneecap. Quadriceps tendinopathy impacts the quadriceps tendon, situated above the kneecap. Both conditions cause pain that worsens with activities involving knee bending, such as squatting, jumping, or climbing stairs.
Bursitis involves inflammation of the bursae, small fluid-filled sacs that reduce friction between bones, tendons, and muscles around the joints. In the knee, prepatellar bursitis, often known as “housemaid’s knee,” affects the bursa in front of the kneecap. This condition causes pain, swelling, redness, and warmth around the affected area. Pain may intensify with movement or pressure, making bending or kneeling particularly uncomfortable.
Chondromalacia Patella is a condition where the cartilage on the underside of the kneecap softens and breaks down. This leads to irritation and pain as the kneecap rubs against the thigh bone when the knee bends. Similar to PFPS, pain often increases with activities like walking up or down stairs or squatting. A grinding or clicking sensation during knee movement is also a common symptom.
When to See a Doctor
While some knee pain can be managed with home care, certain symptoms indicate the need for professional medical evaluation. Seeking timely medical attention can prevent conditions from worsening and ensure appropriate treatment.
Persistent pain that does not improve with rest or self-care measures after a few days requires a doctor’s visit. If the pain is severe enough to affect daily routines, interfere with sleep, or make normal movement difficult, consult a healthcare provider. This includes pain that prevents weight-bearing on the affected leg or causes a limp.
Sudden swelling, redness, or warmth around the knee are signs of inflammation or potential infection requiring prompt medical assessment. An audible “pop” or “snap” during an injury, especially if followed by immediate pain and swelling, suggests a significant structural issue like a ligament or meniscus tear. Such an occurrence requires urgent medical attention.
Other indicators for a medical consultation include the knee locking, catching, or giving way unexpectedly. These sensations suggest mechanical problems within the joint, possibly caused by torn cartilage or loose bodies. Numbness or tingling below the knee, or a fever accompanied by knee pain, indicate nerve involvement or a systemic illness.
Steps for Relief at Home
Managing knee pain at home can support the healing process for mild to moderate discomfort. These self-care strategies focus on reducing inflammation, protecting the knee, and maintaining comfort. Implementing these steps early can help alleviate symptoms.
Resting the affected knee means avoiding activities that aggravate the pain. This allows the knee to heal and prevents further injury or irritation. Reducing weight-bearing activities and limiting prolonged standing can help ease stress on the joint.
Applying ice to the knee reduces swelling and pain. An ice pack or a bag of frozen vegetables, wrapped in a thin towel, should be applied for 15 to 20 minutes every two to three hours. Avoid direct skin contact with ice to prevent cold injury.
Compression reduces swelling and provides support to the knee. A flexible elastic bandage, wrapped securely but not too tightly around the knee, limits fluid buildup. The bandage should not cause numbness, tingling, or increased pain.
Elevating the leg above heart level promotes fluid drainage and reduces swelling. Propping the leg on pillows while resting or sleeping helps fluid move away from the injured area.
Over-the-counter pain relievers offer temporary relief from knee pain and inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen are common choices, as is acetaminophen. Follow dosage instructions and discontinue use if symptoms persist or worsen.
Gentle movement and stretching, if pain allows, maintains flexibility without exacerbating the condition. While rest is important, complete immobility may lead to stiffness. Low-impact activities like cycling or swimming can be considered once pain subsides, but any increase in discomfort requires a return to rest.