The Complete Guide to Knee Osteoarthritis: From Diagnosis to Treatment

Q: Should I use heat or ice for knee arthritis pain?

Both have their place. Use heat (warm shower, heating pad) before activities to loosen stiff joints and improve flexibility. Use ice (20 minutes, wrapped in a towel) after activities to reduce inflammation and swelling. Never apply either directly to skin, and avoid heat if your knee is already hot and swollen.

Key Takeaways

Knee osteoarthritis is the most common joint condition, affecting 32 million Americans
Early treatment with exercise, weight management, and physical therapy can significantly slow progression
A “treatment ladder” approach starts with conservative options before considering more invasive procedures
Modern injection therapies can delay or eliminate the need for surgery in many cases
Knee replacement surgery has a 95%+ success rate when conservative treatments no longer provide relief

If you’re experiencing knee pain that gets worse with activity, morning stiffness, or difficulty climbing stairs, you may be dealing with knee osteoarthritis. This comprehensive guide will help you understand what’s happening in your knee, recognize the symptoms, and navigate the full range of treatment options—from simple lifestyle changes to advanced medical interventions.

What Is Knee Osteoarthritis?

Knee osteoarthritis (often called “wear and tear arthritis”) is a degenerative joint disease where the protective cartilage cushioning your knee bones gradually breaks down over time.

Understanding Your Knee Joint

Your knee is actually three bones working together:

Your femur (thigh bone) on top
Your tibia (shin bone) below
Your patella (kneecap) in front

Smooth, slippery articular cartilage covers the ends of these bones where they meet. Think of this cartilage as a cushion that absorbs shock and allows your knee to bend smoothly. Synovial fluid fills the joint space, providing lubrication—like oil in a car engine.

When osteoarthritis develops:

The cartilage gradually softens, cracks, and wears away
Bones begin rubbing directly against each other
Your body responds by producing extra bone (bone spurs)
The joint becomes inflamed and painful
The synovial fluid becomes less effective at cushioning

This process usually happens slowly over many years, though previous injuries can accelerate it.

Early Warning Signs: Recognizing Knee OA Symptoms

Knee osteoarthritis symptoms typically develop gradually. Many people ignore early signs, assuming it’s just “normal aging.” Recognizing symptoms early gives you the best chance to slow progression.

The Four Cardinal Symptoms

1. Pain That Changes with Activity

The hallmark of knee OA is pain that follows a predictable pattern:

Worse during or after activity (walking, climbing stairs, standing)
Better with rest
Starts as occasional discomfort, becomes more constant over time
Often described as a deep, aching pain

2. Morning Stiffness

Your knee feels “locked up” when you first wake up or after sitting for a while. This stiffness typically:

Lasts 30 minutes or less
Improves once you “work the kinks out”
Gets progressively worse over months and years

3. Decreased Range of Motion

As cartilage wears away and bone spurs form, your knee loses flexibility:

Difficulty fully straightening your leg
Trouble bending your knee completely
Feeling like your knee “catches” or “locks” during movement

4. Swelling and Tenderness

Your knee may look puffy, especially after activity. The joint feels warm to the touch and tender when you press on it.

Other Common Symptoms

Grinding or clicking sensation (crepitus): Feels or sounds like popcorn popping inside your knee
Instability: Your knee feels like it might “give out” when walking
Weather sensitivity: Pain increases during cold, damp weather (many patients report this, though scientists aren’t entirely sure why)
Bone-on-bone sensation: In advanced cases, you may feel a grating sensation

Symptom Progression: The Three Stages

Early Stage: Occasional pain after heavy use, minor stiffness, cartilage begins showing microscopic damage on imaging.

Moderate Stage: Pain becomes more frequent and intense, noticeable during normal daily activities, visible cartilage loss on X-rays, bone spurs begin forming.

Advanced Stage: Constant pain even at rest, severe stiffness and limited mobility, significant cartilage loss, bone rubbing on bone visible on X-rays.

What Causes Knee Osteoarthritis?

While aging is the primary risk factor, knee OA isn’t simply “inevitable” as you get older. Understanding the causes can help you take protective steps.

Primary Risk Factors

Age (The Biggest Factor) After age 50, cartilage’s ability to repair itself declines while normal wear and tear continues. About 50% of people over 65 have some degree of knee OA, though not everyone experiences symptoms.

Previous Knee Injuries Any injury that damages your knee structures increases arthritis risk significantly:

ACL or MCL tears
Meniscus tears
Fractures involving the knee joint
Cartilage damage from sports injuries

Even injuries from 20-30 years ago can lead to arthritis. This is called post-traumatic arthritis.

Excess Weight Every pound of excess body weight adds 3-4 pounds of pressure on your knees with each step. A 10-pound weight gain increases your risk of developing knee OA by 30-40%.

Genetics If your parents or siblings have knee arthritis, you’re more likely to develop it. Researchers have identified specific genes affecting cartilage strength and knee alignment.

Sex Women over 50 are more likely than men to develop knee OA, possibly due to hormonal changes after menopause affecting cartilage health.

Secondary Risk Factors

Repetitive Stress Certain occupations and activities accelerate cartilage breakdown:

Jobs requiring frequent kneeling, squatting, or heavy lifting
High-impact sports (running, basketball, football)
Occupations involving prolonged standing

Joint Misalignment Knock-knees or bowlegs create uneven pressure distribution, causing certain areas of cartilage to wear faster.

Other Medical Conditions

Rheumatoid arthritis (inflammatory arthritis that damages cartilage)
Gout or pseudogout (crystal deposits in joints)
Metabolic disorders affecting bone and cartilage

Muscle Weakness Weak thigh muscles (quadriceps and hamstrings) fail to absorb shock properly, placing more stress directly on knee cartilage.

How Knee Osteoarthritis Is Diagnosed

A proper diagnosis is the first step toward effective treatment. Your doctor uses a combination of approaches.

Medical History

Your doctor will ask detailed questions:

When did your symptoms start?
What makes the pain better or worse?
Do you have morning stiffness? How long does it last?
Have you injured this knee before?
Does arthritis run in your family?
What treatments have you already tried?

Physical Examination

Your doctor will:

Watch you walk to identify limping or gait changes
Check for swelling, warmth, and tenderness
Test your knee’s range of motion
Feel for crepitus (grinding) while moving your knee
Assess muscle strength
Check for joint deformity
Evaluate ligament stability

Imaging Tests

X-rays are the primary diagnostic tool. They show:

Joint space narrowing (indicating cartilage loss)
Bone spurs (osteophytes)
Changes in bone shape and density
Bone cysts

X-rays can’t show cartilage directly (cartilage is invisible on X-rays), but the space between bones indicates how much cartilage remains.

MRI scans aren’t usually needed for diagnosis but may be ordered if:

Your doctor suspects a different problem (meniscus tear, ligament damage)
Symptoms are severe but X-rays appear normal
Surgery is being considered

Blood tests aren’t needed to diagnose osteoarthritis, but your doctor might order them to rule out inflammatory types of arthritis like rheumatoid arthritis.

Severity Grading

Doctors often use the Kellgren-Lawrence grading system based on X-ray findings:

Grade 0: Normal knee
Grade 1: Doubtful narrowing, possible bone spurs
Grade 2: Definite bone spurs, possible joint space narrowing
Grade 3: Moderate joint space narrowing, multiple bone spurs
Grade 4: Severe joint space narrowing, large bone spurs, bone deformity

The Treatment Ladder: From Conservative to Invasive

The key principle in treating knee OA is starting with the least invasive, lowest-risk options and progressing only when needed. This “treatment ladder” approach maximizes benefit while minimizing risk.

Step 1: Lifestyle Modifications (Foundation for Everything)

These are the most important treatments and work for everyone regardless of OA severity.

Weight Management Losing just 10-15 pounds can reduce knee pain by 50% or more. Every pound lost removes 3-4 pounds of pressure from your knees with each step.

Low-Impact Exercise Contrary to old advice, movement helps more than rest. Aim for 30 minutes daily of:

Swimming or water aerobics (water supports 90% of your body weight)
Cycling or stationary biking
Elliptical machines
Walking on flat, even surfaces
Tai chi (improves balance and reduces falls)

Avoid High-Impact Activities During flare-ups, avoid:

Running or jogging
Jumping exercises
Repetitive stair climbing
Deep squatting

Joint Protection Strategies

Use proper body mechanics when lifting
Avoid prolonged kneeling or squatting
Take breaks during activities
Use assistive devices when needed

Step 2: Physical Therapy

A physical therapist designs a personalized program to:

Strengthen quadriceps and hamstring muscles (stronger muscles = less joint stress)
Improve flexibility and range of motion
Correct walking abnormalities
Teach pain management techniques
Show you exercises to do at home

Most insurance covers physical therapy with a referral. Plan on 6-12 sessions initially.

Step 3: Over-the-Counter Medications

Acetaminophen (Tylenol)

Good for mild to moderate pain
500-1,000 mg every 6 hours as needed
Maximum 3,000-4,000 mg per day
Fewer side effects than NSAIDs
Less effective for inflammation

NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)

Ibuprofen (Advil, Motrin): 200-400 mg every 6-8 hours
Naproxen (Aleve): 220-440 mg every 12 hours
Reduce both pain and inflammation
Take with food to protect stomach
Use lowest effective dose for shortest time needed

Important: Long-term NSAID use carries risks (stomach ulcers, kidney problems, increased cardiovascular risk). Discuss with your doctor if you need them regularly.

Topical Treatments

Diclofenac gel or patches (available OTC)
Capsaicin cream (from hot peppers)
Menthol-based creams
Fewer side effects than oral medications

Step 4: Prescription Medications

When OTC options aren’t enough, your doctor might prescribe:

Stronger NSAIDs

Celecoxib (Celebrex): Less stomach irritation than traditional NSAIDs
Meloxicam (Mobic): Once-daily dosing

Duloxetine (Cymbalta)

Originally an antidepressant, now FDA-approved for chronic pain
Works on pain signals in the nervous system
Takes 2-4 weeks to see full effect

Tramadol

Mild opioid pain reliever
For short-term use during severe flare-ups
Can be habit-forming; use cautiously

Step 5: Injection Therapies

When oral medications provide inadequate relief, injections directly into the knee joint can be very effective.

Corticosteroid Injections

Powerful anti-inflammatory medications
Provide rapid relief (often within 48 hours)
Effects last 6 weeks to 6 months
Limited to 3-4 injections per year to avoid cartilage damage
Best for sudden flare-ups

Hyaluronic Acid Injections (Viscosupplementation)

Supplements your knee’s natural lubricating fluid
FDA-approved specifically for knee osteoarthritis
Series of 1-5 injections (depending on brand)
Effects develop over 2-4 weeks
Relief typically lasts 3-6 months or longer
Can be repeated indefinitely
Brands include Synvisc, Euflexxa, Monovisc, Durolane, Orthovisc

Learn more in our complete guide to hyaluronic acid injections.

PRP (Platelet-Rich Plasma) Injections

Uses your own blood cells to promote healing
Emerging research shows promise
Not covered by Medicare or most insurance
Costs $500-$2,000 per injection
Read our evidence review on PRP injections

Step 6: Assistive Devices

Don’t view these as “giving up”—they’re tools that help you stay active.

Knee Braces

Unloader braces shift weight away from damaged cartilage
Compression sleeves provide support and warmth
Can reduce pain by 20-40% during activity

Walking Aids

A cane (held in the hand opposite your bad knee) reduces knee stress by 25%
Walking poles provide stability and reduce joint load
Walkers for severe cases

Orthotics and Shoe Inserts

Cushioned insoles absorb shock
Wedge insoles can improve knee alignment
Proper footwear with good arch support

Step 7: Advanced Procedures

Radiofrequency Ablation

Uses heat to interrupt pain signals from knee nerves
Minimally invasive outpatient procedure
Relief can last 6-12 months
Read more about radiofrequency ablation for knee pain

Knee Arthroscopy

Small surgical procedure to remove loose cartilage fragments
Limited benefit for OA (most effective for mechanical symptoms like locking)
Not recommended for arthritis treatment by most medical organizations

Step 8: Joint Replacement Surgery

When all conservative treatments fail to provide adequate quality of life, total or partial knee replacement may be appropriate.

You might be a candidate if:

Pain significantly limits daily activities
Pain occurs even at rest or at night
Stiffness prevents normal knee movement
Conservative treatments no longer help
X-rays show significant joint damage

What to expect:

Hospital stay of 1-3 days
Walk with assistance the day of or after surgery
6-12 weeks of physical therapy
Return to most activities within 3-6 months
90-95% of patients report significant pain relief
Modern knee replacements last 15-20+ years

Learn more in our guide on when knee replacement is necessary.

Living Well with Knee Osteoarthritis

Daily Pain Management Strategies

Heat vs. Ice Therapy

Heat before activities to loosen stiff joints (warm shower, heating pad)
Ice after activities to reduce inflammation (20 minutes, never directly on skin)
Read our complete guide: Heat vs. Ice for Joint Pain

Pacing Your Activities

Balance activity with rest
Break large tasks into smaller chunks
Avoid prolonged standing or walking
Sit down for tasks when possible

Sleep Position Strategies

Sleep on your back or non-painful side
Place a pillow between knees when side-sleeping
Use a wedge pillow under knees when on your back
Elevate your leg if swollen

Nutrition for Joint Health

While no food can cure arthritis, certain dietary patterns may help reduce inflammation:

Anti-Inflammatory Foods to Emphasize:

Fatty fish (salmon, sardines, mackerel) rich in omega-3s
Colorful fruits and vegetables (berries, leafy greens, tomatoes)
Nuts and seeds (walnuts, chia seeds, flaxseeds)
Olive oil
Green tea

Foods to Limit:

Processed foods and refined carbohydrates
Foods high in added sugars
Red meat and processed meats
Excessive alcohol

Read our complete guide: Anti-Inflammatory Foods for Joint Pain

Exercise Programs That Help

Strengthening Exercises Focus on quadriceps, hamstrings, and hip muscles:

Straight leg raises
Wall squats
Hamstring curls
Hip abduction/adduction

Flexibility Exercises

Gentle knee bends
Hamstring stretches
Calf stretches
Quad stretches

Balance Training

Single-leg stands
Heel-to-toe walking
Tai chi movements

See our illustrated guide: Chair Exercises for Knee Arthritis

Emotional and Mental Health

Chronic pain takes a toll beyond the physical. It’s normal to feel:

Frustrated with limitations
Worried about the future
Anxious about treatment decisions
Sad or depressed about lost abilities

Strategies that help:

Join an arthritis support group
Consider counseling or therapy
Practice stress-reduction techniques (meditation, deep breathing)
Stay socially connected
Set realistic goals and celebrate small victories

Read: The Emotional Toll of Chronic Joint Pain

Questions to Ask Your Doctor

Don’t leave your appointment with unanswered questions. Consider asking:

About Your Diagnosis

What grade of osteoarthritis do I have?
How quickly is it likely to progress?
What caused my knee arthritis?
Are there other problems besides arthritis (meniscus tears, ligament damage)?

About Treatment Options

What treatment do you recommend starting with, and why?
What are the risks and benefits of each option?
How long should I try this treatment before expecting results?
If this doesn’t work, what’s the next step?
Are there clinical trials I might be eligible for?

About Injections

Which injection type is best for my situation?
How many injections will I need?
How long will relief last?
How often can I have injections?
Does my insurance cover this?

About Surgery

When should I start thinking about knee replacement?
Is partial knee replacement an option for me?
What is your experience with knee replacement surgery?
What are the risks specific to my health conditions?
How long is recovery?

Insurance and Medicare Coverage

Understanding coverage can help you access treatments without financial stress.

What Medicare Part B Covers

Doctor visits and diagnostic tests
X-rays and necessary imaging
Physical therapy (with limitations)
Knee injections (both corticosteroid and hyaluronic acid)
Knee replacement surgery
Durable medical equipment (braces, canes, walkers)

What Medicare Typically Doesn’t Cover

Over-the-counter medications and supplements
PRP injections (considered experimental)
Stem cell treatments (not FDA-approved for knee OA)

Prior Authorization Requirements

Some treatments require prior authorization showing you’ve tried conservative approaches first. Your doctor’s office typically handles this paperwork.

For detailed coverage information, see our guide: Medicare Coverage for Joint Injections FAQ

Frequently Asked Questions

Will my knee arthritis definitely get worse over time?

Osteoarthritis is generally progressive, but the rate varies significantly. Some people experience slow progression over decades, while others worsen quickly. Early treatment with weight management, exercise, and appropriate medical care can significantly slow progression. Not everyone with knee OA eventually needs surgery.

Can I reverse knee osteoarthritis or regrow cartilage?

Currently, there’s no proven way to regrow lost cartilage or reverse OA. However, you can slow progression and manage symptoms effectively. Emerging regenerative therapies are being researched but aren’t yet proven effective. Focus on treatments that are proven to help: weight management, exercise, and appropriate medical interventions.

Should I keep exercising if my knee hurts?

Yes, but choose the right activities. Gentle, low-impact exercise is one of the most effective treatments for knee OA. Some discomfort during or after exercise is normal, but sharp pain is a warning sign. Work with a physical therapist to design a safe exercise program. Remember: motion is lotion for arthritic joints.

How do I know if I need a knee replacement?

There’s no single test or X-ray finding that determines readiness for surgery. The decision is based on your pain level, function, and quality of life. If conservative treatments no longer provide adequate relief and arthritis significantly limits your daily activities or enjoyment of life, it may be time to discuss surgery with an orthopedic surgeon.

Are supplements like glucosamine and chondroitin worth taking?

Research on glucosamine and chondroitin shows mixed results. Some studies show modest pain relief, others show no benefit beyond placebo. They’re generally safe but can interact with blood thinners. If you want to try them, give them at least 2-3 months before deciding if they help. Don’t view them as a substitute for proven treatments.

What’s the difference between osteoarthritis and rheumatoid arthritis?

Osteoarthritis is “wear and tear” arthritis caused by cartilage breakdown, typically affecting people over 50. Rheumatoid arthritis is an autoimmune disease where your immune system attacks joint tissue, can occur at any age, and affects multiple joints symmetrically. RA causes more severe inflammation and requires different treatment. Blood tests can distinguish between them.

Can weather really affect my knee pain?

Many people report increased pain during cold, damp weather, though scientists aren’t entirely sure why. One theory is that barometric pressure changes affect joint pressure. Another is that cold weather causes muscles and tendons to tighten. Whether it’s physiological or psychological, staying warm, active, and maintaining treatment during weather changes can help.

Should I use heat or ice for knee arthritis pain?

Both have their place. Use heat (warm shower, heating pad) before activities to loosen stiff joints and improve flexibility. Use ice (20 minutes, wrapped in a towel) after activities to reduce inflammation and swelling. Never apply either directly to skin, and avoid heat if your knee is already hot and swollen.

Next Steps: Taking Control of Your Knee Health

If you suspect you have knee osteoarthritis:

Schedule a doctor’s appointment for proper diagnosis
Start low-impact exercise today—even a 10-minute walk helps
Begin weight management if you’re carrying extra pounds
Keep a pain diary tracking when symptoms are better or worse
Research your insurance coverage for various treatments
Find a physical therapist experienced in treating knee OA
Connect with others through arthritis support groups

Remember: knee osteoarthritis is highly treatable. While there’s no cure, the vast majority of people manage their symptoms effectively with a combination of treatments. You don’t have to accept pain and limitation as inevitable.

Take an active role in your care, work closely with your healthcare team, and don’t give up if the first treatment doesn’t work—there are many options available.

Related Resources:

This guide is for educational purposes only and should not replace advice from your healthcare provider. Always consult with your doctor for diagnosis and treatment of knee pain.

Last medically reviewed: January 2025