According to the Mayo Clinic, chronic knee pain may be caused by damage to the ligaments, tendons or bursae—fluid-filled sacs—that surround the knee, along with the bones, cartilage and ligaments that compose the joint itself. The knee is one of the body's most complex joints, and chronic knee pain often involves more than one pain generator or problem. Conservative care methods may be effective in diminishing chronic knee pain and treating the underlying cause.
Osteoarthritis
Chronic knee pain may be caused by chronic osteoarthritis. The American Academy of Orthopaedic Surgeons (AAOS) states that osteoarthritis, or OA, of the knee is one of the top five causes of disability among elderly men and women, and that the risk for disability from knee OA is comparable to that from cardiovascular disease. Knee OA occurs when the articular cartilage—the smooth fibrous connective tissue that cushions the bones—begins to deteriorate. As the cartilage deteriorates over time, joint space is lost. The bones that help form the knee joint begin to form spurs, or osteophytes. If the joint space narrows enough and the knee joint's articular cartilage is lost, bone ends may rub together and wear away, resulting in knee joint deformity. According to the AAOS, knee osteoarthritis may cause chronic pain and disability. Contributing factors to knee OA include the following: heredity, age, weight, gender, trauma, repetitive stress injuries, high impact sports, poor posture or bone alignment and inappropriate footwear.
Meniscus Tears
Meniscus tears can cause chronic knee pain. According to Dr. Warren Hammer of the Dynamic Chiropractic website, a person with a chronic, degenerative meniscus tear may complain of knee catching, grinding or intermittent pain at the joint line. The Mayo Clinic states that the menisci are C-shaped pieces of cartilage that help stabilize the knee joint, and that a person has two menisci in each knee, one on the inside aspect of the knee, and one on the outside aspect. Meniscus injuries typically involve cartilage tears, which can occur in numerous locations inside the knee joint. Common signs and symptoms of meniscus tears include the following: pain, mild to moderate knee swelling that occurs gradually—even up to 24 to 36 hours post-injury—and an inability to fully extend the knee. A person with a meniscus tear may feel as though her leg is locked in place.
Patellar Tendinitis
Patellar tendinitis can be a cause of chronic knee pain. According the Knee Pain Info website, the patellar tendon is a thick band of tissue that links the inferior pole, or bottom, of the patella or kneecap to the top of the tibia, which is the larger of the two shin bones. The quadriceps—the bulky, powerful muscles on the front of the thigh—extend or straighten the knee by pulling on the patella and patellar tendon. The Knee Pain Info website states that patellar tendinitis occurs when the patellar tendon becomes irritated and inflamed. Patellar tendinitis may be caused by overuse and placing too much strain on the patellar tendon before it's prepared to handle the force to which it's exposed. Micro-tears in the patellar tendon may develop, which lead to inflammation and pain. With continued stress and strain and insufficient rest and recovery, the patellar tendon may be further damaged, and occasionally, the tendon may rupture.
