There are multiple types of arthritis that can occur in the knee:
Osteoarthritis: Protective cartilage that cushions the ends of the bones that form the knee joint erodes and can cause the bones of the knee joint to rub against each other. Painful bone spurs can develop on the ends of the bones resulting in stiffness and limitation of motion.
Post-traumatic arthritis:
Knee injuries can result in arthritis as well, usually resulting in painful swelling.
Gout:
A form of arthritis in which uric acid crystals accumulate in the joints, including the knee joint. The crystals cause pain, swelling, and inflammation.
Rheumatoid Arthritis:
An autoimmune disorder in which the immune system destroys the cartilage in the knee joint. This results in pain, swelling, and softening of the bones of the knee.
Osteoarthritis: Age-related wear and tear. Most commonly affects those over the age of fifty.
Post-traumatic arthritis: Sprains, cartilage tears, sports injuries, falls, motor vehicle injuries, or any other form of injury to the knee.
Gout: Age, family history, obesity, male gender, excessive consumption of meat, seafood, fructose-containing beverages, and alcohol. Some medications, including thiazide diuretics.
Rheumatoid Arthritis: The cause of this autoimmune disorder is undetermined but heredity may play a role
Pain in and around the knee that usually increases with activity and decreases with rest
Swelling
Stiffness in one or both knees, worse when getting out of bed or standing up after a prolonged period of sitting
Crepitus, a crackling noise when moving the knee
Difficulty walking, climbing stairs, and other movements
The diagnosis starts with an accurate history, including family history. The patient is asked about when the pain began, what makes it better or worse, and symptoms such as stiffness and pain. A physical exam will include looking for signs of swelling, tenderness, stiffness, and limitations of motion. The patient may be asked to perform physical tasks such as squatting or walking.
Diagnostic imaging usually includes X-rays, which may show a loss of cartilage in the knee and bone spurs. It is important to note that X-ray findings may not correlate with severity of symptoms. Most people, even if asymptomatic, show signs of arthritis on knee X-rays.
An MRI may be performed if X-rays are inconclusive or the symptoms are suspected to be secondary to a cause other than osteoarthritis. An MRI can provide a view of the soft tissues such as cartilage, menisci, ligaments, tendon, and muscle.
Lab tests, including blood draws and aspiration of fluid from the knee joint, can be used to rule out infections or assist with the diagnosis of gout.
The initial management of knee arthritis should be conservative and focus on exercise for overweight patients, over-the-counter pain relievers, intermittent hot and cold packs, improvements in diet, support devices such as orthotics, and physical therapy.
If the symptoms persist, knee injections with steroids or hyaluronic acid gel may be performed by an interventional pain management physician or an appropriately trained doctor.
If conservative measures and injections do not provide appreciable and long-term relief of symptoms, knee replacement surgery may be considered.