Knee Arthritis Grades 1–4: Stages, Symptoms and Treatment for Each Stage

Knee arthritis grades describe how much wear an X-ray shows in your knee, on a scale from grade 0 (normal) to grade 4 (severe). Grade 1 shows only doubtful changes, grade 2 shows small bone spurs, grade 3 shows clear narrowing of the joint space, and grade 4 means the joint space is almost gone. Most people with grade 1–3 knee arthritis are treated without surgery. Knee replacement is usually considered only for grade 4, or advanced grade 3, when pain and stiffness seriously affect daily life despite other treatment.

Reviewed by Dr. Praful Kilaru, Senior Consultant Joint Replacement & Complex Trauma Surgeon, Yashoda Hospitals, Malakpet, Hyderabad.

Knee Arthritis Grades at a Glance

Doctors most often use the Kellgren–Lawrence (KL) scale, which grades knee osteoarthritis from an X-ray.

The grade is only one part of the picture. Your symptoms, age, activity and general health matter just as much when deciding treatment.

What Is Knee Arthritis?

Knee arthritis, usually osteoarthritis, happens when the smooth cartilage that covers the ends of the thigh bone and shin bone slowly wears thin. As it thins, the bones move closer together, the body forms bony growths called bone spurs (osteophytes), and the joint becomes painful and stiff.

Osteoarthritis often develops over many years. It can affect the inner side of the knee, the outer side, the area behind the kneecap, or the whole joint. To learn the early warning signs, read our guide on the early symptoms of arthritis in the knee.

How Are Knee Arthritis Grades Measured?

Knee arthritis is graded mainly from a standing X-ray of the knee. Standing matters, because the joint space narrows under body weight and shows the true amount of wear.

On the X-ray, the doctor looks at:

• Joint space: the gap between the bones, which shows how much cartilage is left
• Bone spurs (osteophytes): small bony growths at the joint edges
• Sclerosis: hardening and whitening of the bone just under the cartilage
• Deformity: bowing of the leg (bow legs) or knock knees

An MRI can show early cartilage damage that an X-ray cannot, but it is not usually needed to grade typical knee osteoarthritis.

Grade 1 Knee Arthritis (Doubtful)

Grade 1 means the X-ray shows only doubtful changes, such as a possible tiny bone spur, with a normal joint space.

Many people with grade 1 have no symptoms at all. Some notice a mild ache after a long walk, sport or a busy day.

What helps at this stage:

• Regular low-impact exercise such as walking, cycling or swimming
• Strengthening the thigh and hip muscles
• Keeping a healthy weight
• Avoiding repeated deep squatting if it causes pain

Grade 2 Knee Arthritis (Mild)

Grade 2 means there are definite small bone spurs, and the joint space may be slightly narrowed.

You may notice pain after walking long distances or climbing stairs, stiffness after sitting, and occasional mild swelling.

Treatment is still non-surgical:

• A guided physiotherapy programme to strengthen the muscles around the knee
• Weight loss if you are overweight; even a 5–10% loss can noticeably ease knee pain
• Simple pain relief when needed, as advised by your doctor
• Supportive footwear and pacing activities through the day

Our guide on the best exercises for knee pain shows safe exercises to start with.

Grade 3 Knee Arthritis (Moderate)

Grade 3 means several bone spurs, clear narrowing of the joint space and early hardening of the bone ends. The leg may start to bow slightly.

Symptoms are usually more frequent: pain on most days, swelling after activity, stiffness, cracking sounds, and difficulty squatting, sitting cross-legged or using Indian-style toilets.

Treatment at this stage may include:

• Continued exercise and physiotherapy, which remain the foundation of care
• Weight management
• A knee brace or walking stick for support on bad days
• Pain-relief medicines, used carefully and for short periods
• Joint injections in selected cases to settle a painful flare
• Surgery for some patients, such as a realignment operation (osteotomy) or a partial knee replacement when only one part of the knee is worn

Many people with grade 3 still manage well without surgery for years. See our guide on non-surgical treatments for knee pain.

Grade 4 Knee Arthritis (Severe)

Grade 4 means the joint space is almost gone, with large bone spurs and often a visible deformity such as bow legs. The bones may rub directly against each other.

Common problems include pain even at rest or at night, a stiff knee that will not fully bend or straighten, limping, and needing support to walk.

Non-surgical treatment can still ease symptoms for some people, but when pain and stiffness seriously limit daily life, knee replacement surgery is usually the most effective option. Read the signs you need knee replacement surgery to see when it may be time.

Treatment by Stage: A Simple Guide

The table below shows how treatment usually builds up as arthritis progresses.

Can Knee Arthritis Get Worse?

Knee osteoarthritis can slowly progress, but not everyone moves from one grade to the next, and the speed varies a lot from person to person. Some people stay at the same grade for many years.

Things that can speed up progression include being overweight, weak thigh muscles, a previous knee injury such as a meniscus or ligament tear, bow legs or knock knees, and heavy kneeling or squatting at work.

Things that help protect your knee:

• Keeping a healthy weight
• Strengthening the thigh and hip muscles
• Staying active with low-impact exercise
• Getting old knee injuries properly treated

Can Knee Arthritis Be Reversed?

No treatment can currently regrow worn cartilage or reverse the grade seen on an X-ray. However, exercise, weight loss and the right treatment can greatly reduce pain, improve movement and help many people live actively without surgery. Our guide to the diet for knee pain explains which foods help and which to limit.

Be careful of treatments that promise to "cure" or "regrow" knee cartilage. Ask your doctor about the evidence before spending money on them.

When Should You See an Orthopaedic Doctor?

See a doctor if you have:

• Knee pain lasting more than a few weeks
• Swelling that keeps coming back
• Stiffness that makes walking, stairs or sitting difficult
• Pain at night or at rest
• A knee that is bowing, locking or giving way

Seek urgent care for a hot, red, swollen knee with fever, or if you suddenly cannot put weight on the leg.

For more on assessment and treatment options, see our page on osteoarthritis treatment in Hyderabad and knee pain treatment in Hyderabad.

Knee Arthritis Care with Dr. Praful Kilaru in Hyderabad

Dr. Praful Kilaru is a Senior Consultant Joint Replacement and Complex Trauma Surgeon at Yashoda Hospitals, Malakpet, Hyderabad, with 18 years of orthopaedic experience. He assesses knee arthritis at every stage and recommends non-surgical treatment first whenever it is likely to work. Learn more about his orthopaedic practice in Hyderabad, or book a consultation and bring your knee X-rays with you.

References: AAOS OrthoInfo: Arthritis of the Knee · NHS: Osteoarthritis · NIAMS: Osteoarthritis