Causes of Knee Pain

Knees that hurt, throb, swell and ache often interfere with daily life. Because the knee is crucial to mobility, the quality of a person's life is affected if the knee(s) do not work properly or cause pain. Knee pain is classified as chronic or acute.

What causes knee pain?

Chronic knee pain is caused by various conditions, injuries or even infections; acute knee pain is often the result of an injury. Causes of knee pain include, but are not limited to, dislocated kneecap, iliotibial band syndrome, bone fracture, anterior cruciate ligament (ACL) injury, torn meniscus, patellar tendinitis, knee bursitis, osteoarthritis, rheumatoid arthritis, septic arthritis and gout.

A dislocated kneecap happens when the patella bone, which "caps" the front of the knee, shifts or slips outside the knee. A dislocated kneecap is an acute injury that can occur when the knee is forced to change direction too quickly. It can also result from a fall or a blow to the knee. A dislocated kneecap is often visible and apparent. Symptoms include, but are not limited to, pain and difficulty straightening/extending the leg. Diagnosis of a dislocated kneecap is determined by physical examination; however, X-rays are often required to make sure the knee isn’t fractured. Treatment typically involves a physician manipulating the kneecap back in its proper position and putting a splint in place to stabilize the knee. A dislocated kneecap usually heals in approximately 6 weeks.

Iliotibial (IT) band syndrome most often affects distance runners/walkers, cyclists, weightlifters and hikers. IT band syndrome is an overuse injury that develops when the fibrous band of tissue (iliotibial band), which runs from the outer hip to the outer thigh and knee, becomes so tense and taut that it creates friction with the outer section of the femur (thighbone). Symptoms include, but are not limited to, pain, inflammation, warmth and redness on the outside area of the knee, leg pain, and a clicking or popping sound when moving the knee. A physician can diagnose IT band syndrome and provide at-home remedies to treat it. Treatment for IT band syndrome includes resting and icing the knee and using pain relievers to help with inflammation and pain. IT typically resolves in 6 weeks. Physical therapy (to learn proper stretching techniques and exercise form) and massage therapy help promote the healing process and prevent future injury.

Knee fractures and breaks can occur as a result of vehicle crashes, sports injuries, falls, etc. Osteoporosis can also lead to knee fractures. Symptoms of knee fractures include, but are not limited to, moderate to severe knee pain, swelling, redness and warmth. Diagnosis includes a physical examination by a physician and X-rays. Depending on the severity of the fracture, a physician may brace the knee, cast the knee or recommend surgery to fix or replace the kneecap. Self-care includes icing the knee, propping up the leg to reduce swelling and taking pain medication until the knee heals.

Anterior cruciate ligament (ACL) injuries are especially common among soccer, basketball, tennis, football and volleyball players (and any other activity that requires sudden knee rotation, such as gymnastics). ACL injuries occur when the ACL (a ligament that connects the tibia to the femur and keeps the knee joint stabilized) tears. Symptoms include, but are not limited to, immediate severe pain, an audible "popping" noise or sensation in the knee, stiffness, swelling, and difficulty bearing weight or walking. Diagnosis of a torn ACL is determined by physical exam, X-rays, MRI or ultrasound. Treatment for a torn ACL is often physical rehabilitation or surgery. A physician will provide self-care activities and medications if needed.

A torn meniscus often occurs at the same time as a torn ACL. The meniscus is strong, elastic cartilage that protects the area between the shinbone and thighbone. Injury occurs when the knee is rotated too quickly, especially when bearing weight. Symptoms of a torn meniscus are similar to a torn ACL. Diagnosis includes physical examination, X-rays or MRI. In some cases, self-care, such as rest, icing and medication, may be sufficient to heal the injury. In more severe cases, surgery is required.

Patellar tendinitis, or "jumper’s knee," is an aggravation and swelling of the patellar tendon that joins the quadricep muscle to the shinbone. Volleyball players, skiers and those involved in jumping sports are at particular risk for developing patellar tendinitis. A physical examination is usually sufficient for the diagnosis of patellar tendinitis; however, X-rays, MRI or ultrasound may be ordered. Treatment typically involves physical therapy, pain medication and home care. In more severe cases, corticosteroid injections or surgery may be recommended.

Knee bursitis involves inflammation in the bursa(e). Bursae are small sacs of fluid that cushion the knee joint. Inflammation of the bursa(e) can occur due to jobs and activities that require chronic kneeling on hardened surfaces (roofers, sheet metal workers, etc.). It can also occur due to acute injury or infection. Symptoms of knee bursitis are pain, swelling, warmth, redness and limited mobility. A physician can perform a simple physical examination to diagnose bursitis. However, X-rays, MRI or ultrasound may be ordered to rule out complications of knee bursitis or other causes of knee pain and swelling. Treatment involves aspirating fluid from the knee (to determine if infection is present and to ease swelling), medication (antibiotics if infection is present) and physical therapy. Corticosteroid injections or surgery may be recommended if bursitis is chronic and severe.

Arthritis conditions can also cause knee pain; these include osteoarthritis, rheumatoid arthritis, septic arthritis and gout. Sometimes referred to as degenerative arthritis, osteoarthritis develops when the cartilage of the knee degenerates with age. Rheumatoid arthritis is an autoimmune disease: the immune system is falsely alarmed and attacks many joints in the body, including the knee. Septic arthritis develops from an infection in the knee and is often accompanied by a fever. Gout occurs when uric acid crystals accumulate in the knee joint (However, gout most often occurs in the big toe). A primary-care physician can diagnose these forms of arthritic knee pain with a physical examination, X-rays or blood work. A referral to a rheumatologist for further testing and treatment may be ordered. Treatment for arthritic knee pain includes medication (anti-inflammatory or antibiotic), physical therapy or surgery.