Knee Osteoarthritis Stages: The Best Treatment for Each

The stages of knee osteoarthritis can help explain how joint changes become more noticeable over time.

If you have been told that you have “Grade 2,” “Grade 3,” or “severe knee osteoarthritis,” you may immediately start wondering: 

Is my knee getting worse? Do I need surgery? Can physiotherapy still help? Can I reverse the damage?

As a physiotherapist, I want you to know something important before we discuss the stages: 

the number on your X-ray does not tell the entire story.

Two people can have the same Kellgren-Lawrence grade and completely different levels of pain and disability.

Conversely, someone with relatively modest X-ray changes can have considerable pain.

Research has repeatedly demonstrated this disconnect between structural changes seen on imaging and the symptoms a person actually experiences.

A 2025 analysis using data from 4,796 people with knee OA found that radiographic and MRI features were surprisingly poor predictors of individual pain and symptoms. (Wolters Kluwer)

That is why I do not treat an X-ray. I treat the person in front of me.

Your knee strength, walking pattern, range of motion, balance, confidence, activity level, body weight, pain sensitivity and daily function all matter when deciding what treatment you need.

Here is how the commonly used stages of knee osteoarthritis work and what I would prioritize at each stage.

What Are the Stages of Knee Osteoarthritis?

The most commonly discussed radiographic classification is the Kellgren-Lawrence system, which grades knee osteoarthritis from 0 to 4.

It is useful for describing structural changes, but it should not be interpreted as a perfect measure of pain severity or physical disability.

The broad progression looks like this:

Stage	Kellgren-Lawrence grade	Typical X-ray findings	What you may experience
Stage 0	Grade 0	No radiographic OA	Usually no OA symptoms
Stage 1	Grade 1	Doubtful/minimal changes	Occasional stiffness or discomfort
Stage 2	Grade 2	Definite osteophytes, possible joint-space narrowing	Activity-related pain and stiffness
Stage 3	Grade 3	Multiple osteophytes, definite narrowing, sclerosis	More frequent pain, stiffness and functional limitation
Stage 4	Grade 4	Severe narrowing, large osteophytes, sclerosis and deformity	Significant pain, stiffness and loss of function

The important point is that these stages describe radiographic severity, not a guaranteed pain timeline.

In fact, older population research found that many people with radiographic knee OA did not report significant pain, while many people with knee pain did not have advanced radiographic OA. (BMC)

That distinction changes how I approach treatment.

Stage 0: No Radiographic Osteoarthritis, But Prevention Starts Here

Stage 0 essentially means that there is no visible radiographic osteoarthritis.

But this does not mean that you should wait until an X-ray shows damage before taking care of your knees.

If you have risk factors such as previous knee injury, repeated joint loading, muscle weakness, sedentary behavior, excess body weight or poor physical conditioning, this is actually an excellent time to improve your knee capacity.

The best treatment at Stage 0: Build capacity, not fear

My priority at this stage is strength, movement quality and physical capacity.

That means progressively training:

• Quadriceps
• Hamstrings
• Gluteal muscles
• Calf muscles
• Hip abductors
• Balance and proprioception
• Cardiovascular fitness

One lesser-known point is that quadriceps weakness may occur before obvious knee symptoms become severe.

A longitudinal study involving nearly 1,000 knees found that people with the lowest quadriceps strength had a higher risk of developing radiographic knee OA. (Wiley)

This does not mean that weak quadriceps alone cause osteoarthritis.

OA is multifactorial. But it tells us that muscle capacity is an important modifiable factor.

What I would avoid

I would not recommend becoming obsessed with avoiding every squat, stair, lunge or hill.

A healthy joint needs appropriate loading.

The goal is not to make your knee “fragile” by protecting it from movement.

The goal is to gradually make it better prepared for movement.

Stage 1: Very Early or Doubtful Osteoarthritis

Stage 1 is where X-ray findings may be minimal or questionable.

You may experience:

• Occasional knee discomfort
• Stiffness after prolonged sitting
• Mild discomfort after unusually heavy activity
• Reduced confidence during stairs
• A feeling that one knee is “not as strong”
• Occasional clicking or creaking

And here is a physiotherapy insight I wish more people knew:

Clicking does not automatically mean cartilage is being destroyed.

Knee noises can occur for several reasons and, in isolation, are not a reliable measure of disease progression.

The best treatment at Stage 1: Early strengthening and activity modification

This is an excellent stage to establish a sustainable exercise routine.

I would usually combine:

Strength training:
Start with exercises such as sit-to-stand, supported squats, step-ups,bridges, calf raises and progressive knee extension work, depending on the individual’s examination.

Aerobic activity:
Walking, cycling, swimming or other enjoyable cardiovascular exercise can improve overall physical capacity.

Neuromuscular training:
Balance, controlled step-downs and single-leg activities can help address movement confidence and coordination.

Recent evidence continues to support exercise as one of the central treatments for knee OA.

A network meta-analysis involving 39 studies and 2,646 participants found that multiple forms of exercise improved pain or function compared with control conditions. (Sage Journals)

A lesser-known target: eccentric strength

Many people focus exclusively on how strong their quadriceps are during simple straightening movements.

But your knee also needs to control movement while your body is moving downward.

Think about:

• Going downstairs
• Sitting into a chair
• Walking downhill
• Landing from a step
• Decelerating

These require eccentric muscle control.

Research in people with early knee OA has identified impairments in eccentric quadriceps performance even when some measures of concentric strength were less affected. (PubMed)

That is one reason I often assess how a person controls a step-down rather than simply asking whether they can straighten their knee against resistance.

Stage 2: Mild to Moderate Knee Osteoarthritis

Stage 2 is often where people begin receiving a clear X-ray diagnosis.

Typical radiographic findings include definite osteophytes and possible narrowing of the joint space.

Symptoms may include:

• Pain while walking for longer periods
• Discomfort on stairs
• Morning stiffness
• Pain after sitting for a long time
• Difficulty squatting
• Reduced walking speed
• Occasional swelling
• Reduced confidence in the affected leg

This stage is extremely important because people sometimes make one of two mistakes.

They either ignore the problem completely, or they become frightened and stop moving.

Neither approach is ideal.

The best treatment at Stage 2: Progressive exercise plus symptom management

This is where I would focus heavily on progressive loading.

Your exercise should not remain at the same easy level forever.

For example, if you can comfortably perform 15 sit-to-stands, the next step may eventually involve resistance, a deeper range, a slower eccentric phase or a more demanding functional variation.

The principle is simple:

Your knee needs a reason to adapt.

A 2024 systematic review and network meta-analysis examining 41 studies and more than 2,200 participants found benefits from different forms of lower-limb strengthening for pain, function and muscle strength. (Frontiers)

Don’t confuse post-exercise discomfort with damage

This is one of the most important conversations I have with patients.

Some people believe:

“If my knee hurts during exercise, I must be damaging the cartilage.”

That is not necessarily true.

Exercise can temporarily increase symptoms, particularly when you are starting a new program or increasing the load too quickly.

NICE specifically advises that people with osteoarthritis may experience increased pain when beginning therapeutic exercise, while emphasizing that regular long-term exercise is beneficial. (NICE osteoarthritis recommendations)

Instead of using an all-or-nothing approach, I prefer load management.

If an exercise produces a significant flare that lasts well beyond the session, the volume, intensity, range or frequency may need adjusting.

The answer is usually not “stop forever.”

Stage 2 Weight Management: One of the Most Powerful Modifiable Factors

If you have overweight or obesity, weight management can become an important component of knee OA treatment.

But I would never reduce the treatment conversation to “lose weight because your knees are overloaded.”

The relationship is more complicated.

Body weight influences mechanical loading, but metabolic and inflammatory pathways may also play a role in osteoarthritis.

A systematic review and meta-analysis found that losing approximately 5% to 10% of body weight was associated with improvements in pain, disability and physical quality of life in adults with knee OA and obesity. (Wiley)

More recent evidence comparing weight-loss interventions suggests that diet plus exercise can improve pain compared with control interventions, while the most effective strategy varies between individuals. (Elsevier)

As a physiotherapist, I would therefore focus on making movement easier and more sustainable rather than prescribing a crash diet.

Stage 3: Moderate to Advanced Knee Osteoarthritis

Stage 3 usually involves more obvious structural changes:

• Multiple osteophytes
• Definite joint-space narrowing
• Subchondral sclerosis
• More substantial structural changes

This is often the stage when people start saying:

“My X-ray says bone-on-bone. Is exercise still safe?”

The answer requires nuance.

If your knee is painful and functionally limited, exercise can still be one of the most important treatments.

The best treatment at Stage 3: Individualized rehabilitation

At this stage, I would usually look beyond the knee itself.

I want to know:

• How much quadriceps strength have you lost?
• Can you fully straighten the knee?
• Can you bend it sufficiently for daily activities?
• How do you walk?
• Can you climb stairs?
• Can you get up from a chair?
• Is your hip also weak?
• Is your balance reduced?
• Are you avoiding activities because of fear?
• How much does pain interfere with sleep?
• What activities matter most to you?

These answers often tell me more about the treatment plan than the X-ray grade alone.

Strength training remains important

A common misconception is that advanced OA means you should only perform gentle stretching.

Stretching can be useful, but it does not replace strengthening.

A large body of evidence supports strengthening and other forms of therapeutic exercise for reducing symptoms and improving function.

Recent evidence involving 217 randomized trials and more than 15,000 participants found moderate-certainty evidence supporting several exercise modalities for pain, function, gait and quality of life in knee OA. (BMJ Open)

Balance deserves more attention than it receives

Here is another underappreciated problem: people with knee OA may develop poorer proprioception and balance.

That can create a vicious cycle:

Pain → less movement → weaker muscles → poorer balance → less confidence → even less movement.

A 2025 systematic review and meta-analysis found that exercise improved balance measures in people with knee OA, with multicomponent programs showing meaningful improvements in several analyses. (MDPI)

This is why rehabilitation should not consist only of sitting on a chair and performing knee extensions.

Your knee is part of a moving body.

Stage 3 and the Role of Knee Braces

A brace is not automatically necessary for everyone with knee OA.

However, some patients with specific patterns of disease, particularly certain compartmental or alignment-related problems, may benefit from an appropriately selected brace.

This should be individualized rather than purchased simply because an advertisement says “orthopedic knee support.”

Research examining neuromuscular adaptations and unloader braces suggests that bracing can influence neuromuscular activity,

but the clinical decision should still be based on the person’s symptoms, alignment, compartment involved and functional goals. (Wolters Kluwer)

A brace should be viewed as a tool, not a replacement for rehabilitation.

Stage 4: Severe Knee Osteoarthritis

Stage 4 represents severe radiographic OA.

The X-ray may show:

• Marked joint-space narrowing
• Large osteophytes
• Subchondral sclerosis
• Possible deformity
• Major structural changes

People at this stage may experience:

• Significant pain during walking
• Severe stiffness
• Difficulty climbing stairs
• Difficulty standing for long periods
• Reduced walking distance
• Trouble getting out of a chair
• Reduced knee range of motion
• Visible alignment changes
• Major impact on quality of life

But even here, Stage 4 does not automatically mean that physiotherapy is pointless.

The best treatment at Stage 4: Optimize function and determine whether surgery is appropriate

At this stage, physiotherapy can help you:

• Preserve or improve strength
• Maintain available knee range
• Improve walking efficiency
• Improve balance
• Reduce fear of movement
• Adapt daily activities
• Improve cardiovascular fitness
• Prepare for possible surgery
• Recover after surgery

The important distinction is that physiotherapy may not reverse advanced structural degeneration, but it can still substantially influence what you are capable of doing with that knee.

When Should Knee Replacement Be Considered?

Knee replacement should not be decided solely because an X-ray says “Grade 4.”

The more meaningful question is:

How much is your knee problem affecting your life, and have appropriate non-surgical treatments stopped providing enough benefit?

NICE recommends considering joint replacement when symptoms such as pain, stiffness, reduced function or progressive deformity substantially affect quality of life and non-surgical management is ineffective or unsuitable.

It also specifically advises against using numerical disease-severity scores as the sole basis for referral.

This is an important distinction.

A person with severe X-ray changes who can walk comfortably, exercise and sleep may not have the same urgency as someone with similar imaging who cannot walk to the bathroom without severe pain.

Physiotherapy before surgery is not wasted time

Prehabilitation can help you enter surgery in better physical condition.

If surgery eventually becomes appropriate, I want my patient to have the strongest and most mobile knee and body possible within their limitations.

And if surgery is not immediately necessary, rehabilitation may improve function enough to postpone or reconsider the need for an operation.

The Biggest Myth: “Bone-on-Bone Means You Should Stop Exercising”

This is one of the most harmful beliefs I encounter.

Exercise does not need to be aggressive to be effective.

You can modify:

• Range of motion
• Resistance
• Repetitions
• Speed
• Frequency
• Exercise position
• Impact level

For someone who cannot tolerate long walks, cycling may be easier.

For someone who cannot tolerate deep squats, partial-range strengthening may be appropriate.

For someone who struggles with land-based exercise, aquatic exercise can provide an alternative environment.

The objective is not to find one magical “best exercise for knee arthritis.”

The objective is to find the right dose of the right exercise for your current capacity.

A Surprisingly Useful Option: Tai Chi

Tai Chi is sometimes dismissed as too gentle to count as rehabilitation.

That is a mistake.

It combines controlled movement, balance, coordination and mind-body elements.

A 2026 randomized clinical trial involving 178 people with knee OA found that a 12-week unsupervised online Tai Chi intervention produced greater improvements in knee pain and function than an education control. (JAMA Internal Medicine)

This does not mean Tai Chi should replace progressive strengthening.

Instead, it demonstrates an important physiotherapy principle:

The best exercise is often the one you can perform consistently.

What About Manual Therapy?

Manual therapy may have a role, particularly when stiffness or movement restriction is limiting function.

But I would not build an entire knee OA treatment plan around massage or joint mobilization.

Current NICE guidance recommends manual therapy for knee OA only alongside therapeutic exercise and states that evidence is insufficient to support manual therapy alone as the main management strategy.

In other words:

Hands-on treatment can support rehabilitation.

It should not replace rehabilitation.

What About Painkillers, Injections and Other Treatments?

Medication decisions should be individualized and discussed with an appropriately qualified medical professional,

especially if you have kidney disease, gastrointestinal problems, cardiovascular disease, take anticoagulants or have other medical conditions.

For knee OA, topical NSAIDs are strongly recommended in the OARSI non-surgical management guideline for appropriate patients,

while oral medications and injections require consideration of risks, comorbidities and individual circumstances. (OARSI guideline)

Intra-articular corticosteroid injections may provide short-term symptom relief for selected patients, but they should be considered as part of a broader treatment strategy rather than a permanent solution.

The same principle applies to other treatments marketed as cartilage “regeneration.”

Be very cautious with claims that a particular supplement, injection or device will regrow your knee cartilage naturally.

A trustworthy treatment plan should distinguish between:

symptom relief, functional improvement and structural modification.

They are not the same thing.

One of the Most Important Things to Avoid: Treating the X-Ray Instead of the Person

I often tell patients:

“Your X-ray is information, not a verdict.”

A 2025 analysis found that neither radiographic features nor MRI OA scores accurately predicted individual pain and symptoms. (NCBI)

Another study demonstrated that people with similar radiographic grades can have substantially different pain sensitivity. (PMC)

This helps explain why two patients sitting beside each other in an X-ray department can receive the same radiological grade but have completely different experiences.

Pain is influenced by more than cartilage and bone.

The nervous system, sleep, stress, previous pain experiences, physical capacity, inflammation, beliefs about movement and overall health can all influence how symptoms are experienced.

The Lesser-Known Knee OA Problem: Losing Strength While Trying to Protect the Knee

This is the vicious cycle I most want you to avoid.

You experience pain.

So you stop walking.

Then you stop taking stairs.

Then you stop squatting.

Then you avoid exercise.

Your muscles become weaker.

Daily tasks become harder.

Your knee becomes less capable of handling normal loads.

You become more fearful of movement.

And activity falls even further.

This is why “rest until the knee is completely pain-free” is usually not a good long-term strategy.

Your rehabilitation program should be adjusted to your symptoms, but complete inactivity is rarely the destination.

A Practical Stage-by-Stage Treatment Roadmap

Stage 0 to Stage 1

Prioritize:

• Strength training
• Aerobic fitness
• Healthy body weight where appropriate
• Movement confidence
• Balance
• Injury prevention
• Regular physical activity

The goal is building reserve capacity.

Stage 2

Prioritize:

• Progressive quadriceps and hip strengthening
• Aerobic exercise
• Functional training
• Load management
• Weight management when appropriate
• Education about pain
• Addressing movement limitations

The goal is controlling symptoms while increasing capacity.

Stage 3

Prioritize:

• Individualized strengthening
• Balance and neuromuscular training
• Range-of-motion work
• Walking optimization
• Activity modification
• Weight management when appropriate
• Appropriate pain-management strategies
• Bracing when clinically indicated

The goal is maintaining independence and function.

Stage 4

Prioritize:

• Strength preservation
• Range of motion
• Safe mobility
• Balance
• Pain management
• Functional independence
• Prehabilitation if surgery is being considered
• Orthopedic evaluation when symptoms substantially affect quality of life

The goal is maximizing quality of life and making an informed decision about further treatment.

Five Things I Would Tell Every Knee OA Patient

1. Don’t wait for zero pain before exercising

A completely pain-free starting point is not always realistic.

Instead, your physiotherapist can help you find an appropriate exercise dose and progression.

2. Don’t judge your knee solely by its X-ray

Your walking ability, strength, range of motion, pain, confidence and daily function matter.

3. Don’t only strengthen the knee

Your hip, ankle and trunk influence how your lower limb moves and handles load.

4. Don’t suddenly increase your activity because you had one good day

One pain-free day does not necessarily mean your knee is ready for a sudden jump from 2,000 to 10,000 steps.

Increase activity progressively.

5. Don’t believe that severe OA automatically means “nothing can be done”

Even when structural changes are advanced, rehabilitation can improve strength, mobility, balance and function.

Red Flags: When Knee Pain Needs Medical Assessment

Knee OA is common, but not every painful knee is caused by osteoarthritis.

Seek medical evaluation if you have:

• A major traumatic injury
• Inability to bear weight after injury
• A hot, markedly swollen knee with fever
• Sudden severe swelling without a clear explanation
• A locked knee
• Rapidly worsening symptoms
• Significant unexplained weight loss or systemic symptoms
• Severe night pain that is unusual for you
• New neurological symptoms

These situations may require assessment for conditions other than routine osteoarthritis.

Final Word From a Physiotherapist

If you remember only one thing from this article, let it be this:

The stage of your knee osteoarthritis does not define the future of your knee.

Radiographs can show structural changes, but they cannot tell me exactly how you will walk tomorrow, how strong your muscles can become, how much confidence you can regain or how much your quality of life can improve.

For early-stage OA, I want to build capacity before disability becomes established.

For moderate OA, I want to improve strength, movement and load tolerance while controlling symptoms.

For advanced OA, I want to preserve independence, optimize function and help you make an informed decision about injections, specialist review or surgery when appropriate.

And for every stage, I want you to stop thinking of your knee as a fragile structure that must be protected from movement.

Your knee needs an appropriate amount of movement, strength and load.

The treatment changes with the stage, but the principle remains the same:

Don’t simply chase the X-ray.

Build the strongest, most capable version of the knee you have.

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Medical Disclaimer!

This article has been reviewed and written under the guidance of our Head Physiotherapist, Dr. Kruti Raj (PT, MUHS,CPT,CMPT). The information shared is intended for educational purposes only and should not be considered a substitute for personalized medical advice, diagnosis, or treatment.

Please consult us or any other qualified healthcare professional before beginning any exercise program, especially if you are experiencing pain, recovering from injury, or managing a medical condition.