Early symptoms that accompany the swelling can include
The arthritis conditions are other common causes of knee damage that can lead to a swollen knee. Swelling in the knee area can result due to damage or disease of any of the structures of the knee area and knee joint, including bones, tendons, ligaments, menisci, muscles, skin, bursae, or blood vessels.
Other causes of swollen knee
- Collateral Ligament Injuries
- Joint Dislocation
- Posterior Cruciate Ligament (PCL) Injury
- Tendon Tear
- Torn Ligaments
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
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Causes of Swollen Knee
A Baker's cyst, also called a popliteal cyst, is swelling caused by knee joint fluid protruding to the back of the knee (popliteal area of the knee). Not uncommon, Baker's cysts can be caused by virtually any type of joint swelling (arthritis). They are often resolved with removal of excess knee fluid in conjunction with cortisone injections.
Broken Bone (Types of Bone Fractures)
A broken bone is a fracture. There are different types of fractures, such as: compressed, open, stress, greenstick, spiral, vertebral compression, compound, and comminuted. Symptoms of a broken bone include pain at the site of injury, swelling, and bruising around the area of injury. Treatment of a fracture depends on the type and location of the injury.
A bursa is a fluid-filled sac found in the joints that cushions them. Bursitis is an inflammation of the bursae, most commonly caused by repetitive motion. Bursitis can be caused by a bacterial infection and should be treated with antibiotics. Doctors also recommend icing and resting the joint.
Chondromalacia Patella (Patellofemoral Syndrome)
Chondromalacia patella (housemaid's knee or secretary's knee) results from misalignment of the kneecap as it slides over the lower end of the thigh bone. Symptoms include tightness or fullness in the knee area, swelling, and mild discomfort. Treatment includes the use of anti-inflammatory medications, in addition to stretching, strengthening and icing the knee.
Buildup of uric acid crystals in a joint causes gouty arthritis. Symptoms and signs include joint pain, swelling, heat, and redness, typically of a single joint. Gout may be treated with diet and lifestyle changes, as well as medication.
Medial Collateral Ligament (MCL) Injury
The medial collateral ligament (MCL) is one of four ligaments that stabilize the knee. MCL injuries are referred to as tears or sprains. Sprains are graded from 1-3 based on the severity of the injury. Symptoms and signs of MCL injuries include swelling, pain, stiffness, and limping. Treatment of MCL injuries may involve resting and bracing the affected knee, and physical therapy can help to restore the range of motion.
Osgood-Schlatter disease, a painful inflammation just below the knee but above the shin, typically affects adolescent boys. Symptoms include localized pain, inflammation, swelling, and calcification. Osgood-Schlatter disease typically goes away over time, however, symptoms can be helped with anti-inflammatory and pain-relieving medications, ice, and rest.
Osteoarthritis is a type of arthritis caused by inflammation, breakdown, and eventual loss of cartilage in the joints. Also known as degenerative arthritis. Osteoarthritis can be caused by aging, heredity, and injury from trauma or disease.
Pseudogout, a form of arthritis, results when deposits of crystals collect in and around the joints. Symptoms of pseudogout include pain, stiffness, warmth, and joint swelling of the knees, ankles, hips, shoulders, and/or wrists. Treatment for pseudogout aims to decrease inflammation through the use of nonsteroidal anti-inflammatory drugs, ice, and rest.
Reactive arthritis is a chronic, systemic rheumatic disease characterized by three conditions, including conjunctivitis, joint inflammation, and genital, urinary, or gastrointestinal system inflammation. Inflammation leads to pain, swelling, warmth, redness, and stiffness of the affected joints. Non-joint areas may experience irritation and pain. Treatment for reactive arthritis depends on which area of the body is affected. Joint inflammation is treated with anti-inflammatory medications.
Rheumatoid Arthritis (RA)
Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Because it can affect multiple other organs of the body, rheumatoid arthritis is referred to as a systemic illness and is sometimes called rheumatoid disease. The 16 characteristic early RA signs and symptoms include the following. Anemia Both sides of the body affected (symmetric) Depression Fatigue Fever Joint deformity Joint pain Joint redness Joint stiffness Joint swelling Joint tenderness Joint warmth Limping Loss of joint function Loss of joint range of motion Many joints affected (polyarthritis)
Septic arthritis, or infectious arthritis, is infection of one or more joints by bacteria, viruses, or fungi. Symptoms and signs of septic arthritis include fever, joint pain, chills, swelling, redness, warmth, and stiffness. Treatment involves antibiotics and the drainage of the infected joint.
Sprains and Strains
An injury to a ligament is called a sprain, and an injury to muscle or tendon is called a strain. Sprains and strains may be caused by repetitive movements or a single stressful incident. Symptoms and signs include pain and swelling. Though treatment depends upon the extent and location of the injury, rest, ice, compression, and elevation are key elements of treatment.
Torn ACL (Anterior Cruciate Ligament Tear)
The anterior cruciate ligament helps to prevent the top and bottom of the knee from sliding back and forth. Symptoms and signs of a torn ACL include knee pain and swelling. Treatment of a torn ACL depends upon the health of the patient and the patient's expectations and willingness to undertake extensive physical therapy. Rehabilitation after surgical repair of an ACL tear may take more than nine months.
A torn meniscus (knee cartilage) may be caused by suddenly stopping, sharply twisting, or deep squatting or kneeling when lifting heavy weight. Symptoms of a meniscal tear include pain with running or walking long distances, popping when climbing stairs, a giving way sensation, locking, or swelling. Treatment depends upon the severity, location, and underlying disease of the knee joint.
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