Arthritis Types

Why we care about the type

Arthritis is inflammation of a joint. That sounds simple, but the word covers a huge range of causes. Two people can walk into the clinic with a swollen knee and have completely different diseases requiring completely different treatments. Getting the type right is the first step.

Osteoarthritis, mechanical wear

Osteoarthritis (OA) is mechanical breakdown of the joint’s cartilage, usually from repetitive use, prior injury, or years of load-bearing. Unlike rheumatoid arthritis, it’s not an autoimmune disease. The body isn’t attacking itself; the cartilage is simply wearing away, bone is rubbing on bone, and the joint becomes inflamed in response.

Classic signs of OA:

• Asymmetric, affects weight-bearing joints on one side more than the other (one knee more than the other, for instance).
• Weight-bearing joints most affected, knees, hips, spine, feet. Shoulders and wrists are less common.
• Morning stiffness under 30 minutes, when you get out of bed, the joint feels stiff, but it loosens quickly with activity.
• Pain with activity, relief with rest, stairs, walking, kneeling hurt; sitting with the leg elevated feels better.
• Usually starts in your 50s or 60s, though early-onset OA (from injury or overuse) can happen younger.

We treat OA with activity modification, NSAIDs, physical therapy, bracing, cortisone injections, and sometimes hyaluronic acid or PRP injections before considering surgery.

Rheumatoid arthritis, autoimmune disease

Rheumatoid arthritis (RA) is a systemic autoimmune disease where the body’s immune system attacks the synovial lining of joints. It’s not about wear and tear; it’s the immune system misfiring. The disease itself belongs to a rheumatologist, who manages it with medications that calm the immune attack. An orthopedic surgeon enters the picture later, and only for some patients: when years of that inflammation have damaged a joint past what medication can fix.

Classic signs of RA:

• Symmetric, if the left hand is swollen, the right hand usually is too, roughly equally.
• Small joints first, fingers, wrists, toes, hands. Knees and hips can be involved but usually come later.
• Morning stiffness over 1 hour, after sleeping, the joints are stiff, swollen, and painful for more than an hour. This is a hallmark sign.
• Pain at rest too, unlike OA, RA can hurt when you’re not moving.
• Positive rheumatoid factor or anti-CCP antibodies, a blood test that confirms the autoimmune process.

RA is treated with disease-modifying antirheumatic drugs (DMARDs) and biologic agents, medications that suppress the immune attack. The earlier these are started, the better the outcome. Cortisone injections can help manage flares, but they’re not the primary treatment.

Where orthopedics comes in is the damage the disease leaves behind. Sustained inflammation of the joint lining can wear away cartilage, stretch or rupture the tendons around a joint, and leave the joint itself deformed or unstable. Those are mechanical problems, and once they have developed they are treated the same way as any worn-out joint: a cortisone injection to settle a painful flare, and, when a joint is genuinely past saving, knee, hip, or shoulder replacement to rebuild it. Better biologic medication has made that late-stage surgery less common than it once was, but when RA has destroyed a joint, restoring it is orthopedic work.

Other types worth knowing

Psoriatic arthritis occurs in some people with psoriasis (a skin condition). It can resemble RA but is tied to the skin disease and requires similar systemic treatment.

Gout is a crystalline arthritis: uric acid crystals form in the joint and trigger a severe, sudden inflammatory flare. Knees and feet are common sites. It responds well to NSAIDs or cortisone injections during the flare, but long-term management requires controlling uric acid levels with medication like allopurinol.

Post-traumatic arthritis develops after a significant joint injury (fracture into the joint surface, ligament injury). Years later, the damaged cartilage breaks down and arthritis forms at that site. Treatment is the same as osteoarthritis.

Why it matters for treatment

An OA knee and an RA knee may look similar on an X-ray, but the treatment plan is completely different. OA is primarily an orthopedic problem we manage locally. RA is a systemic disease: rheumatology has to stop the immune attack first, and orthopedics steps in for the joints it has already damaged. Misdiagnosing one as the other can cost months of ineffective treatment. A simple blood test (rheumatoid factor, anti-CCP, ANA) often clarifies the picture.

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