Types of Arthritis That Affect the Knee

Physical therapist helping patient on exam table with knee stretches

Many adults struggle with routine aches and pains as they age. While osteoarthritis is the most common cause of knee pain, there are other forms of arthritis that also affect the knee, such as rheumatoid arthritis and psoriatic arthritis. Fortunately, several treatments are available to mitigate symptoms and help patients enjoy a higher quality of life without invasive joint surgery. With offices in Oregon, Washington, and Arizona, the team at Reflex Knee Specialists offers comprehensive knee evaluations to identify the underlying conditions that cause knee arthritis. Here, we briefly summarize the different types of arthritis that affect the knee joints.


Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder that primarily affects joints. While the cause is unknown, the risk of developing RA increases with age. Rates are higher among women than men. This form of arthritis most commonly affects the hands and wrists, but may also involve the knee.

Patients with RA often have symptom flare-ups followed by periods of remission. Symptoms include:

  • Joint stiffness and swelling
  • Pain that’s worse after intensive exercise or periods of rest
  • Clicking, locking, or grinding sensation in the joints
  • Joint weakness and fatigue

There is no cure for RA, but there are effective treatments that can slow the progression of the disease. Patients with RA may take medications including corticosteroids, nonsteroidal anti-inflammatory drugs, and biologics that suppress the body’s immune response.



Osteoarthritis (OA) is the most common form of arthritis and usually affects people with a prior knee injury (e.g. ACL or meniscal tear) and adults over age 45. Characterized by chronic inflammation, the OA process results in cartilage breakdown and dysfunctional biomechanics. Signs and symptoms of OA include joint stiffness and swelling, as well as pain that gets worse with exercise or activity.

Although there is no cure for osteoarthritis, there are several treatments that can minimize the symptoms without surgery. These include:

Supplements, nutrition, and lifestyle changes can also help improve joint health.


Psoriatic Arthritis

This form of arthritis develops alongside psoriasis, a chronic disorder that causes patches of red, scaly, irritated skin. While anyone can get psoriatic arthritis, it is most common among adults between ages 30 and 50. The National Psoriasis Foundation reports that psoriatic arthritis often develops about 10 years after the onset of psoriasis itself.

Patients with psoriatic arthritis may experience symptoms that include:

  • Joint pain and stiffness
  • Redness and swelling in the hands and feet
  • Pitted or crumbling nail beds
  • Lower back pain

While there isn’t a cure for psoriatic arthritis, certain medications can help ease symptoms. These include:

  • Corticosteroids
  • Nonsteroidal anti-inflammatory medicines (NSAIDs)
  • Biologics

Physical therapy can also help ease pain and improve a patient’s range of motion.


Crystal-induced Arthritis

Calcium pyrophosphate dihydrate crystal deposition disease (CPPD) is a form of arthritis that mostly affects older adults. CPPD is caused by calcium crystals that develop in joint cartilage and synovial fluid. It’s not clear why these crystals form, but they can cause symptoms including joint pain, swelling, and stiffness. The joints may be red or warm to the touch.

This type of crystal-induced arthritis is also known as pseudogout because the symptoms are similar to gout, another crystal-induced arthritis that is caused by urate crystals in the joint fluid. CPPD most often affects the knees and wrists; gout typically affects the big toe and/or knee joints. A sample of synovial fluid may be analyzed to confirm a diagnosis of CPPD.

Treatments for crystal-induced arthritis include anti-inflammatory drugs and corticosteroids. Patients with gout and elevated serum levels of uric acid may be put on a medication to lower urate levels (Allopurinol). Joint injection treatments may offer pain relief and help reduce swelling.


Get Knee Arthritis Treatment at Reflex Knee Specialists

The experienced providers at Reflex Knee Specialists offer comprehensive knee evaluations to identify the underlying conditions that cause knee arthritis and will recommend treatments based on the underlying cause of knee pain. Offering a wide range of treatment options, our team develops customized care plans for each patient from our offices in Portland, Oregon; Bellevue, Washington; and Tempe, Arizona. For more information on diagnosing and treating arthritis and to schedule an appointment, call 503-719-6783 or contact us today.

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