Knee stiffness describes a feeling of tightness or restricted movement in the knee joint. This common complaint can range from mild, temporary sensations to persistent mobility limitations. It often makes everyday activities like walking, bending, or straightening the leg challenging. Understanding the reasons behind this stiffness is an important step toward finding relief.
Everyday Reasons for Stiffness
Many people experience knee stiffness that is not a cause for concern and often resolves on its own. Stiffness can occur after extended periods of inactivity, such as sitting for a long time or waking up in the morning. This occurs because synovial fluid, which lubricates the joint, does not circulate adequately when the joint is still. Gentle movement helps redistribute this fluid, allowing the knee to move more smoothly. Minor muscle soreness or slight strains from unaccustomed physical activity can also lead to temporary knee stiffness.
Common Conditions Causing Stiffness
Knee stiffness can also signal underlying medical conditions. One frequent cause is osteoarthritis, a degenerative condition where knee joint cartilage gradually wears down. This breakdown leads to increased friction between bones, causing pain, swelling, and stiffness, especially after rest. Rougher joint surfaces impede smooth movement.
Rheumatoid arthritis, an autoimmune disease, causes the immune system to attack the synovial membrane lining the knee joint. This attack results in inflammation and swelling, leading to knee pain and stiffness. Inflammation can thicken the synovial membrane and eventually damage cartilage and ligaments, further restricting movement. This condition often affects both knees symmetrically.
Acute knee injuries, such as meniscus tears or ligament sprains, can also cause stiffness. A meniscus tear, affecting knee cartilage, can cause irritation and fluid buildup, contributing to stiffness. Ligament sprains, such as an anterior cruciate ligament (ACL) injury, can result in swelling and pain, mechanically limiting knee motion. Scar tissue following injuries or surgery can also lead to chronic knee stiffness by restricting flexibility.
Patellar tendinitis, or jumper’s knee, is another source of knee stiffness. This condition often arises from repetitive stress on the tendon, like jumping or running, causing tiny tears and inflammation. Stiffness is a common symptom, especially in the morning or after rest, alongside pain below the kneecap. Bursitis, inflammation of fluid-filled sacs (bursae) that cushion the joint, can also cause knee stiffness. Overuse or direct strain commonly trigger bursitis, leading to local inflammation and restricted movement.
A Baker’s cyst, or popliteal cyst, is a fluid-filled swelling behind the knee. These cysts form when excess synovial fluid, often from underlying conditions like arthritis or meniscus tears, accumulates in the popliteal bursa. This fluid-filled lump can cause tightness, discomfort, and stiffness, particularly when bending or straightening the knee.
Patellofemoral pain syndrome (PFPS) describes pain and stiffness around the kneecap. This syndrome is linked to overuse from activities that repeatedly stress the knee, such as running or climbing stairs. Abnormal kneecap tracking or muscle imbalances around the knee can contribute to PFPS irritation and stiffness. Stiffness can worsen after prolonged sitting with the knee bent.
Important Considerations and Warning Signs
While many instances of knee stiffness are minor, certain symptoms signal a need for medical evaluation. Seek professional attention if stiffness is accompanied by significant swelling, redness, or warmth around the joint, indicating inflammation or infection. Severe pain preventing weight bearing or interfering with daily activities warrants immediate consultation.
Other warning signs include a locking or catching sensation in the knee, suggesting a mechanical issue. A fever alongside knee stiffness could indicate an infection requiring prompt treatment. Consult a healthcare provider if stiffness worsens over time, does not improve with self-care, or if you notice a joint deformity.
Managing Stiffness at Home
Several home strategies can relieve mild knee stiffness. Gentle movement and stretching can improve joint flexibility and promote synovial fluid circulation. Low-impact activities like walking or cycling are beneficial. Heat or cold therapy can also alleviate discomfort; heat relaxes muscles and improves circulation, while cold reduces inflammation and pain.
Over-the-counter pain relievers, like NSAIDs or acetaminophen, may help manage pain and reduce inflammation. Consult a doctor or pharmacist before using these medications to ensure they are appropriate. Resting the knee from aggravating activities, while avoiding complete immobility, allows for recovery without causing further stiffness.
Maintaining a healthy weight is important for managing knee stiffness, especially if related to osteoarthritis. Losing even a small amount of weight can significantly reduce load and stress on the knee joints. For instance, losing one pound of body weight can remove four pounds of pressure from the knees. This reduction in pressure also helps decrease inflammation, lessening stiffness and pain.