A Ginza clinic providing knee joint regenerative medicine and regenerative aesthetics

Reservation
TEL

Cartilage Wears Down Silently | The Complete Knee Care Guide

Why “no pain” doesn’t mean no damage — and what to do about it now

Two older women stretching outdoors — knee care and preventive exercise habits at Ginza YR Clinic
The short answer

By the time osteoarthritis becomes painful, cartilage damage is often already significant. Because cartilage has almost no pain-sensing nerves, deterioration accumulates quietly, long before any symptoms appear. The most important window to protect your joints is right now — before the pain begins.

Note: The rate and pattern of joint deterioration varies between individuals. Not everyone will follow the same progression.

That first step out of bed feels heavier than it should. After hours at a desk, standing up comes with a familiar stiffness. Going downstairs, your knee gives way just a little. Most people meet these moments with a familiar reasoning: “It’s not really painful, I’ll keep an eye on it.” “It loosens up once I get moving.”

What often goes unnoticed is what’s happening inside the joint during that waiting period. A symptom disappearing is not the same as a joint recovering. The most important window to protect your joints is right now, before the pain begins.

Why Osteoarthritis Progresses Without Warning

The most fundamental reason is that cartilage contains almost no pain-sensing nerves. Unlike muscle or skin, damaged cartilage sends no immediate distress signal to the brain. Deterioration accumulates quietly, entirely below the threshold of awareness.

Cartilage also has no direct blood supply. Once injured, it cannot draw on the nutrients that blood delivers, which makes natural repair extremely limited. The idea that careful use will allow cartilage to restore itself simply does not hold up.

As these factors compound, cartilage thins, synovial fluid diminishes, and bone-on-bone friction increases. Persistent pain typically does not appear until the joint has crossed into osteoarthritis. Pain is not the beginning of the problem — it is a delayed signal of a problem already well advanced.

Knee joint cross-section showing cartilage damage and inflammation alongside a woman holding her knee — osteoarthritis progression at Ginza YR Clinic
Deterioration begins before pain appears

When Should You Start? A Decade-by-Decade Guide

Some people sail through their thirties feeling fine, only to notice knee discomfort in their forties. Others manage their symptoms well into older age through consistent care. Knee health cannot be reduced to a matter of age alone. Worth noting: research shows that women develop osteoarthritis at roughly twice the rate of men (National Institutes of Health). The decline in estrogen following menopause is thought to reduce cartilage-protective function, making intentional knee care especially important for women in their fifties and beyond.

30s
Build the foundations now
Strength, weight, and movement quality. The return on investment is highest at this stage
40s
Don’t dismiss early signals
Early cartilage changes become more likely. Consider an annual check with a specialist
50s+
Don’t ignore symptoms — get imaging
Osteoarthritis risk rises sharply, especially in women. Imaging can clarify the current state of the joint

Is Your Knee Giving You Signals? A Quick Self-Check

Early signs are subtle and easy to dismiss. How many of the following sound familiar?

Do you notice any of the following?
The first few steps in the morning feel stiff or heavy (eases once you get moving) Monitor
A dull ache or heaviness after extended walking or exercise (fades with rest) Monitor
A sudden give or mild pain when walking downstairs Monitor
A clicking, grinding, or grating sensation when bending the knee (crepitus) Monitor
Difficulty rising from a low position after squatting or kneeling Monitor
A feeling of tightness, pressure, or unusual heaviness in the knee Monitor

⚠ These symptoms may come and go. That cycle is not a sign of recovery — it may reflect shifting conditions inside the joint. Because cartilage has almost no pain-sensing nerves, deterioration can continue even during symptom-free periods. Dismissing these signs as trivial is one of the most common reasons minor damage becomes serious damage.

Seven Things You Can Do for Your Knees Starting Today

Protecting your joints is not about finding one perfect solution. It is about building several good habits and sticking with them.

step 01

Strengthen the Muscles That Support the Knee

The knee does not work alone. Three muscle groups share the load: quadriceps (front of the thigh) for forward-backward stability; hamstrings (back of the thigh) to absorb impact; and gluteal and hip abductor muscles to stabilize the hip and reduce lateral stress on the knee.

You do not need gym equipment. Straight-leg raises (SLR) and seated leg lifts are effective and accessible. Aim for at least three sessions per week, and always include stretching before and after.

step 02

Move Better, Not Just More

How you move through daily life shapes how long your joints last. Going downstairs: slow down and keep the knee from caving inward. Getting up from a chair: use your thigh muscles rather than pushing off with momentum. At a desk: stand and move at least once an hour.

The real risk is not exercise itself but repeating movements with poor mechanics. Improving movement quality can significantly reduce the cumulative load your joints absorb over time.

step 03

Manage Your Weight

The relationship between body weight and joint stress is direct. Research suggests that each kilogram of additional body weight adds roughly three to four kilograms of force across the knee during walking. Bringing weight into a healthy range reduces that load continuously, day after day. In terms of joint protection, weight management may offer the best return of any single habit.

step 04

Keep Moving Without Overdoing It

Rest is not always the answer when your knee is bothering you. Moderate movement helps circulate synovial fluid and deliver nutrients to cartilage. Low-impact activities such as walking, aquatic exercise, and cycling support long-term joint health when maintained consistently.

That said, pushing through pain does more harm than good. The guiding principle: move within a pain-free range, every day, a little at a time.

step 05

Feed Your Joints from the Inside

What you eat influences the internal environment of your joints just as much as how you exercise.

Omega-3 fatty acids
Salmon, mackerel, walnuts, flaxseed oil. Associated with reducing inflammatory activity within the joint
Vitamins C & D
Broccoli, bell peppers, salmon, egg yolks. Involved in collagen synthesis and bone density maintenance
Collagen foods & antioxidants
Chicken wings, bone broth, leafy greens, green tea. A structural component of cartilage; relationship with oxidative stress reduction is under ongoing study

Note: High-sugar diets, ultra-processed foods, and excessive alcohol may contribute to chronic inflammation.

step 06

Take Old Injuries Seriously

Injuries that seemed minor at the time can quietly shift the mechanical balance of a joint — ligament sprains, repeated stress to the meniscus, accumulated wear from sport or repetitive activity. All can become long-term risk factors.

Returning to normal activity once pain subsides is not the same as full recovery. Confirm that range of motion and muscle strength have genuinely returned to pre-injury levels. Early rehabilitation often turns out to be the deciding factor in a joint’s long-term health.

step 07

Manage Inflammation Before It Becomes Chronic

Low-grade chronic inflammation — the kind that runs continuously below the level of symptoms — is one of the primary drivers of joint degeneration. Poor sleep, chronic stress, excess body fat, and training without adequate recovery all contribute.

Caring for your joints means managing not just how you use them, but the inflammatory state of your body overall.

When Lifestyle Changes Are Not Enough: Regenerative Medicine as an Option

Lifestyle modification is the foundation of joint care, and that will not change. But when it is no longer sufficient on its own, PRP therapy and adipose-derived stem cell (ASC) therapy may be worth considering. They become relevant in situations such as:

✓ Early cartilage wear confirmed on imaging
✓ Persistent inflammation that has not responded adequately to conservative treatment
✓ Incomplete recovery following injury
✓ A preference to delay or avoid surgery
PRP Therapy

Concentrating growth factors from the patient’s own blood and injecting them into the joint to reduce inflammation and support tissue repair. Because it requires only a blood draw, the procedural burden is relatively low. Most commonly considered for early to moderate osteoarthritis.

ASC Therapy (Adipose-Derived Stem Cells)

Stem cells harvested from the patient’s own subcutaneous fat and delivered into the joint. Through paracrine signaling, these cells work to reduce inflammation and improve the joint environment. ASC involves more procedural steps than PRP and is typically considered when the condition is more advanced, or when PRP has not provided sufficient improvement.

Note: PRP therapy and ASC therapy are performed in compliance with Japan’s Act on the Safety of Regenerative Medicine. Efficacy varies by individual. End-stage osteoarthritis (bone-on-bone) may fall outside the range where these treatments are applicable. We conduct a comprehensive assessment before recommending any treatment.

A Knee Health Checklist to Start Today

  • ✓Strengthen the quadriceps, hamstrings, and hip abductors at least three times per week
  • ✓Pay attention to movement mechanics when using stairs, rising from chairs, and lifting
  • ✓Keep your weight within a healthy range to minimize ongoing joint load
  • ✓Include anti-inflammatory foods in daily meals: fish, vegetables, and quality fats
  • ✓Stay active within a pain-free range through walking, aquatic exercise, or similar activities
  • ✓If any symptoms persist for more than two weeks, see a specialist rather than waiting
  • ✓Confirm with a professional that past injuries have genuinely healed

“Pain is not the starting point. It is a signal that arrives late.” The earlier you act, the more you have to work with.

Note: This article is for general informational purposes only and does not guarantee specific treatment outcomes. ASC therapy is performed in compliance with Japan’s Act on the Safety of Regenerative Medicine, and results vary by individual.

Thinking About Next Steps?

Ginza YR Clinic interior — regenerative medicine and joint care specialist clinic in Tokyo
Ginza YR Clinic, Tokyo

If you have been wondering about the actual condition of your knee, here is a simple two-step starting point:

Step 1: Get an X-ray or MRI to establish a clear picture of your current joint health

Step 2: Bring your results to a regenerative medicine specialist to discuss whether conservative care is sufficient, or whether PRP or ASC therapy may be a relevant option for you

► Learn more about ASC therapy at Ginza YR Clinic

Consultations & Appointments

References
  • National Institute of Arthritis and Musculoskeletal and Skin Diseases. Osteoarthritis. https://www.niams.nih.gov/health-topics/osteoarthritis
  • Loeser RF, et al. Osteoarthritis: A Disease of the Joint as an Organ. Arthritis Rheum. 2012.
  • Katz JN, Arant KR, Loeser RF. Diagnosis and Treatment of Hip and Knee Osteoarthritis: A Review. JAMA. 2021.
  • Chen D, et al. Osteoarthritis: Toward a Comprehensive Understanding of Pathological Mechanism. Bone Res. 2017.
  • Pak J, et al. Adipose-derived stem cells and their secretome for knee osteoarthritis treatment. J Clin Med. 2018.
PAGE TOP
Reservation
TEL