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Stages of osteoarthritis

Osteoarthritis (OA) is divided into five stages. Stage 0 is assigned to a normal, healthy knee. The highest stage, 4, is assigned to severe OA. OA that has become this advanced is likely to cause significant pain and disrupt joint movement.

Stage 0 OA is classified as “normal” knee health. The knee joint shows no signs of OA and the joint functions without any impairment or pain.


No treatment is needed for stage 0 OA.

A person with stage 1 OA is showing very minor bone spur growth. Bone spurs are boney growths that often develop where bones meet each other in the joint.

Someone with stage 1 OA will usually not experience any pain or discomfort as a result of the very minor wear on the components of the joint.


Without outward symptoms of OA to treat, many doctors will not require you to undergo any treatments for stage 1 OA.

However, if you have a predisposition to OA or are at an increased risk, your doctor may recommend you take supplements, such as chondroitin, or begin an exercise routine to relieve any minor symptoms of OA and to slow the progression of the arthritis.

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Stage 2 OA of the knee is considered a “mild” stage of the condition. X-rays of knee joints in this stage will reveal greater bone spur growth, but the cartilage is usually still at a healthy size, i.e. the space between the bones is normal, and the bones are not rubbing or scraping one another.

At this stage, synovial fluid is also typically still present at sufficient levels for normal joint motion.

However, this is the stage where people may first begin experiencing symptoms—pain after a long day of walking or running, greater stiffness in the joint when it’s not used for several hours, or tenderness when kneeling or bending.


Talk with your doctor about your possible signs of OA. Your doctor may be able to detect and diagnose the condition at this early stage. If so, then you can develop a plan to prevent the condition from progressing.

Several different therapies can help relieve the pain and discomfort caused by this mild stage of OA. These therapies are mainly non-pharmacologic, which means you do not need to take medicine for symptom relief.

If you are overweight, losing weight through diet and exercise can relieve minor symptoms and improve your quality of life. Even people who are not overweight, will benefit from exercise.

Low-impact aerobics and strength training can help strengthen the muscles around the joint, which increases stability and decreases the likelihood of additional joint damage.

Protect your joint from exertion by avoiding kneeling, squatting, or jumping. Braces and wraps can help stabilize your knee. Shoe inserts can help realign your leg and relieve some of the pressure you put on your joint.

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Some people may require medication for mild pain relief. These are usually used in conjunction with nonpharmacological therapies. For example, if you need to take NSAIDs or acetaminophen (such as Tylenol) for pain relief, you should also try exercise, weight loss, and protecting your knee from unnecessary stress.

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Long-term therapy with these medicines may cause other problems. NSAIDs can cause stomach ulcers, cardiovascular problems, and kidney and liver damage. Taking larger doses of acetaminophen may cause liver damage.

Stage 3 OA is classified as “moderate” OA. In this stage, the cartilage between bones shows obvious damage, and the space between the bones begins to narrow. People with stage 3 OA of the knee are likely to experience frequent pain when walking, running, bending, or kneeling.

They also may experience joint stiffness after sitting for long periods of time or when waking up in the morning. Joint swelling may be present after extended periods of motion, as well.


If nonpharmacological therapies do not work or no longer provide the pain relief they once did, your doctor may recommend a class of medications known as corticosteroids.

Corticosteroid drugs include cortisone, a hormone which has been shown to relieve OA pain when injected near the affected joint. Cortisone is available as a pharmaceutical drug, but it’s also produced naturally by your body.

Some corticosteroid injections can be administered three or four times a year. Others, such as triamcinolone acetonide (Zilretta), are only administered once.

The effects of a corticosteroid injection wear off in about two months. However, you and your doctor should look at the use of corticosteroid injections carefully. Research shows long-term use can actually worsen joint damage.

If over-the-counter NSAIDs or acetaminophen are no longer effective, prescription pain medicine, such as codeine and oxycodone, can help relieve the increased pain common in stage 3 OA. On a short-term basis, these medicines can be used to treat moderate to severe pain.

However, narcotic medicines are not recommended for long-term use due to the risk of increased tolerance and possible dependence. Side effects of these medicines include nausea, sleepiness, and fatigue.

People who don’t respond to conservative treatments for OA—physical therapy, weight loss, use of NSAIDs and analgesics—may be good candidates for viscosupplementation.

Viscosupplements are intra-articular injections of hyaluronic acid. A typical treatment with a viscosupplement requires one to five injections of hyaluronic acid, given one week apart. There are a few injections that are available as a single-dose injection.

The results of a viscosupplementation injection are not immediate. In fact, it may take several weeks for the full effect of the treatment to be felt, but relief from symptoms typically lasts a few months. Not everyone responds to these injections.

Stage 4 OA is considered “severe.” People in stage 4 OA of the knee experience great pain and discomfort when they walk or move the joint.

That’s because the joint space between bones is dramatically reduced—the cartilage is almost completely gone, leaving the joint stiff and possibly immobile. The synovial fluid is decreased dramatically, and it no longer helps reduce the friction among the moving parts of a joint.


Bone realignment surgery, or osteotomy, is one option for people with severe OA of the knee. During this surgery, a surgeon cuts the bone above or below the knee to shorten it, lengthen it, or change its alignment.

This surgery shifts the weight of your body away from the points of the bone where the greatest bone spur growth and bone damage has occurred. This surgery is often done in younger patients.

Total knee replacement, or arthroplasty, is a last resort for most patients with severe OA of the knee. During this procedure, a surgeon removes the damaged joint and replaces it with a plastic and metal device.

Side effects of this surgery include infections at the incision site and blood clots. Recovery from this procedure takes several weeks or months and requires extensive physical and occupational therapy.

It is possible that replacing your arthritic knee won’t be the end of your OA knee problems. You may need additional surgeries or even another knee replacement during your lifetime, but with the newer knees, it may last for decades.