The 4 Stages of Osteoarthritis: What Each Means

Osteoarthritis is often described in four stages, from minor changes with little pain to severe joint changes. Knowing the stages helps explain what your X-ray report means, but there is an important catch: how much pain you have often does not match what an X-ray shows.

This guide explains the four stages of osteoarthritis, what helps at each one, and why the stage is only part of the picture.

What helps at every stage: NICE recommends exercise, and weight management where it applies, as the core treatment for osteoarthritis at every stage, before injections or surgery are considered. A physiotherapist can build that programme around your joint and your goals. Physiotherapy in Chiswick needs no GP referral, and a 70-minute first appointment with assessment and treatment is £99. Book online or call 020 4515 0000.

Quick answer

The four stages of osteoarthritis are stage 1 (minor), stage 2 (mild), stage 3 (moderate) and stage 4 (severe). They come from X-ray grading, most often the Kellgren and Lawrence scale, which scores bony growths and narrowing of the joint space from grade 0 (normal) to grade 4. Your stage does not always match your pain, and exercise helps at every stage.

How osteoarthritis is staged

Stages are usually based on an X-ray scoring system that looks at the space between the bones, small bony growths called osteophytes, and changes in the bone surface. The joint space narrows as the cartilage covering the bone ends thins.

The most widely used system, the Kellgren and Lawrence scale, grades an X-ray from 0, with no signs of osteoarthritis, to 4, the most severe. There is no stage 5 in this system. The same four grades are used for the knee, the hip and other joints.

The four signs of osteoarthritis on an X-ray

• Loss of joint space: the gap between the bones narrows as cartilage thins. In the knee this is usually most marked on the inner side of the joint.
• Osteophytes: small bony growths at the edges of the joint.
• Subchondral sclerosis: the bone just under the cartilage becomes denser and shows up whiter.
• Subchondral cysts: small fluid-filled spaces in the bone under the cartilage.

Doctors sometimes remember these with the word LOSS. A report may mention some or all of them.

Stage 1: minor

Very small bony growths may be seen, with little or no narrowing of the joint space. Most people have no pain or only occasional stiffness. This is the ideal time to build strength and stay active.

Stage 2: mild

Bony growths are clearer and the joint space may start to narrow slightly. People often notice stiffness after sitting or first thing in the morning, and aching after activity. Strengthening exercise, staying active and managing weight make the biggest difference here.

Stage 3: moderate

There is definite narrowing of the joint space and more bony growths. Pain is more frequent, particularly with walking, stairs, kneeling or getting up from a chair, and the joint may swell after activity. Physiotherapy, a structured strength programme, weight loss where relevant and pain management help most people stay active.

Stage 4: severe

The joint space is markedly reduced and the bone ends may be close together. Pain and stiffness are present on most days, and movement is reduced. Exercise still helps, and joint replacement is an option to discuss when pain and function remain poor despite other treatment.

Why the stage is only part of the picture

X-ray findings and symptoms often do not match. Many people with stage 3 or 4 changes have little pain, while others with mild changes have significant pain. For this reason, UK guidance says osteoarthritis can usually be diagnosed without an X-ray in people over 45 with typical symptoms, and decisions about treatment, including surgery, are based on your symptoms and function rather than the X-ray alone.

Does osteoarthritis always get worse?

No. Osteoarthritis does not inevitably progress through all four stages. Many people stay stable for years, and symptoms often improve with the right exercise, even when X-ray changes remain.

What helps at every stage

• Strengthening exercise for the muscles around the joint, two or three times a week
• Regular activity such as walking, cycling or swimming
• Weight loss where relevant, which reduces load on knees and hips
• Supportive footwear for knee and hip osteoarthritis
• Heat for stiffness and pacing on busy days

When to see a doctor

• Pain is stopping you sleeping or doing daily tasks
• The joint locks or gives way
• You want to discuss joint replacement
• Same day: a joint that suddenly becomes hot, red and very swollen, especially with fever

Frequently asked questions

What stage of osteoarthritis needs a knee replacement?

It depends on symptoms, not the stage alone. Replacement is considered when pain and loss of function significantly affect your life despite exercise and other treatments.

Can you reverse osteoarthritis?

The X-ray changes cannot be reversed, but symptoms often improve a great deal with strengthening, weight loss and staying active.

How fast does osteoarthritis progress?

Usually slowly, over years. Many people never reach the severe stage.

Do you get inflammation with osteoarthritis?

Sometimes. The joint lining can become mildly inflamed, so the joint may swell or feel warm after a busy day. This is different from inflammatory arthritis such as rheumatoid arthritis, and blood tests for inflammation are usually normal in osteoarthritis. A joint that becomes suddenly hot, red and very swollen needs same-day medical advice.

Is osteoarthritis a disability?

It can be. Under the Equality Act 2010, a condition counts as a disability if it has a substantial and long-term effect, lasting or likely to last 12 months or more, on your ability to do normal daily activities. Whether osteoarthritis meets this depends on how much it affects you, not on the X-ray stage.

Is walking good for osteoarthritis?

Yes. Walking is one of the best activities for knee and hip osteoarthritis at every stage.

Osteoarthritis care in Chiswick

Osteoarthritis is assessed and treated at Omnia Lifestyle, 8 to 9 Bedford Corner, The Avenue, Chiswick W4 1LZ, close to Turnham Green station, on bus routes 94, E3 and 272. Limited parking is available on request when booking. Assessment builds a strength programme matched to your joints and goals, whatever stage your X-ray shows.

A physiotherapy initial assessment and treatment takes 70 minutes and costs £99, with our HCPC registered physiotherapists. Physiotherapy is recognised by AXA Health, Aviva, WPA and Vitality. If getting to the clinic is difficult, home visit physiotherapy is available in West London from £110.

Read more about osteoarthritis and knee pain, see what arthritis feels like and our knee pain exercises, explore physiotherapy, red light therapy and tai chi, or book an assessment.

This article is general information, not medical advice. If you have any of the warning signs listed above, seek medical attention.