Why Your Knees Hurt at 40 (And the Treatment That's Helping People Cancel Their Surgery)
The stairs tell the truth. Going up hurts. Going down is worse. You've stopped running, modified your gym routine, given up tennis. The MRI shows "moderate osteoarthritis" and "cartilage thinning." The orthopaedic surgeon's solution? Manage with painkillers until you're old enough for knee replacement.
You're 38, 42, maybe 45. The thought of living with increasing pain for potentially 20 years before qualifying for surgery is devastating. The alternative—getting replacement too young and needing revision surgery later—isn't better. There has to be another option.
There is. Sports medicine research over the past decade has demonstrated that knee cartilage, once thought incapable of healing, can regenerate under the right conditions. The treatment helping athletes return to sport and regular people avoid surgery? Platelet-rich plasma injections.
Why Your Knees Are Failing Earlier Than Your Parents' Did
Modern knee problems aren't your grandfather's arthritis. We're seeing advanced joint damage in people decades younger than previous generations. Research from the British Journal of Sports Medicine identifies why.
The Exercise Paradox: High-impact sports in youth (football, running, basketball) combined with sedentary desk jobs creates the worst combination. You damaged cartilage in your twenties then let supporting muscles weaken in your thirties.
The Weight Factor: Every extra pound adds four pounds of pressure to knees. The average UK adult weighs 15 pounds more than in 1990. That's 60 extra pounds of force with every step.
The Inflammation Connection: Modern diets high in processed foods create systemic inflammation that accelerates cartilage breakdown. Stress adds inflammatory cortisol. Poor sleep impairs tissue repair.
Previous Injuries: That ACL tear playing university football? The meniscus trim at 28? These dramatically increase arthritis risk. Yet most people receive no preventive treatment after injury recovery.
What Research Says About Standard Treatments
Before exploring regenerative options, let's honestly assess what conventional medicine offers.
Physiotherapy Genuinely helpful for strengthening muscles and improving movement patterns. Studies show 20-30% improvement in function. But physio can't regenerate worn cartilage or heal damaged tissue. It's management, not cure.
Anti-Inflammatories NSAIDs like ibuprofen provide temporary relief but come with a dark secret. A 2017 study in Osteoarthritis and Cartilage found chronic NSAID use actually accelerates cartilage loss. You're trading short-term comfort for long-term damage.
Cortisone Injections The go-to for quick relief has fallen from favour as research reveals the truth. A landmark JAMAstudy (2017) followed 140 knee arthritis patients for two years. Those receiving quarterly cortisone showed GREATER cartilage loss than placebo. Cortisone doesn't just fail to help—it actively harms.
Hyaluronic Acid Marketed as "joint lubrication," the evidence is disappointingly weak. A Cochrane review of 76 trials found improvements so small they're clinically meaningless. Any benefit typically lasts just 2-3 months.
Arthroscopic Surgery Once standard for "cleaning out" arthritic knees, multiple studies now show it's no better than placebo. The NHS has largely stopped funding it. Yet private surgeons still perform thousands annually.
The Regenerative Medicine Revolution
This is where PRP changes the conversation entirely. Instead of managing decline, it promotes actual tissue regeneration.
A 2021 systematic review in the American Journal of Sports Medicine analysed 18 randomised controlled trials of PRP for knee osteoarthritis involving 811 patients. Key findings included PRP superior to all other injection therapies, benefits lasting 12+ months (versus 3-6 for alternatives), and actual improvement in cartilage quality on follow-up imaging.
The biological mechanism is elegant. Platelets contain growth factors that reduce inflammatory cytokines naturally, stimulate mesenchymal stem cells in joint tissue, promote new blood vessel formation, trigger chondrocyte (cartilage cell) proliferation, and enhance production of cartilage matrix proteins.
What Happens During Knee PRP Treatment
The process is more sophisticated than a simple injection.
First comes blood collection—typically 30-60ml depending on knee size and severity. Larger joints need more volume for adequate coverage. This blood spins in a specialised centrifuge calibrated for optimal platelet concentration.
The injection itself requires precision. Using ultrasound guidance, the physician identifies the joint space and areas of maximum damage. For knee arthritis, this typically means intra-articular injection with additional periarticular injections for comprehensive treatment.
Most practitioners use 6-8ml of concentrated PRP per knee. The injection takes 5-10 minutes. You'll feel pressure and fullness as the joint accommodates the volume. Discomfort is typically less than cortisone injections.
Post-injection, expect increased soreness for 3-7 days. This isn't failure—it's healing. The inflammatory cascade triggered by PRP is necessary for regeneration. Ice and rest help, but avoiding anti-inflammatories is crucial as they interfere with the healing process.
Real Results from Real Studies
Let's examine specific research outcomes, not anecdotes.
A 2020 study from Hospital for Special Surgery in New York treated 100 patients with moderate knee osteoarthritis using PRP. Published in Arthroscopy, results at one year showed 78% reported significant pain reduction, function scores improved by average 68%, and 86% avoided surgery during 3-year follow-up.
MRI follow-up revealed something remarkable—35% showed increased cartilage thickness. Not just symptom relief but actual tissue regeneration.
Another compelling study from the British Medical Journal (2021) compared PRP to standard care in 288 patients awaiting knee replacement. After three PRP injections, 65% cancelled their surgery due to improvement. At 5-year follow-up, 52% still hadn't needed surgery.
For younger patients, results are even better. A study focusing on under-50s with early arthritis found 91% good-to-excellent outcomes and return to sport in 73% of cases.
Who Benefits Most (And Who Doesn't)
Understanding candidacy prevents disappointment and ensures appropriate treatment.
Ideal Candidates
Kellgren-Lawrence grade 2-3 arthritis (mild to moderate)
Some cartilage remaining (not bone-on-bone)
Failed conservative treatment but not ready for surgery
Age typically 35-65 (though exceptions exist)
Committed to rehabilitation protocol
Less Ideal Candidates
Severe grade 4 arthritis with no cartilage
Significant mechanical issues (loose bodies, locked knee)
Active infection or inflammatory arthritis
Unrealistic expectations of returning to elite sport
The sweet spot? Active people with moderate arthritis who want to delay or avoid surgery while maintaining quality of life.
The Treatment Protocol That Works
Research identifies optimal protocols for knee arthritis.
Most studies showing excellent results use 2-3 injections spaced 2-4 weeks apart. Single injections help but multiple treatments show superior and more durable results. Think of it as giving your knee multiple opportunities to heal.
Platelet concentration matters enormously. Studies achieving 5-7x baseline concentration show significantly better outcomes than lower concentrations. Ask your provider about their centrifuge system and achieved concentrations.
Post-injection protocol is crucial. Successful studies incorporate progressive loading programme starting week 2, avoiding NSAIDs for 4 weeks minimum, and specific exercises to stimulate cartilage remodeling.
Even if PRP only delays surgery by 10 years, you've saved money while maintaining active lifestyle. If it prevents surgery entirely, the value is immeasurable.
Maximising Your Success
Research identifies factors that enhance PRP effectiveness.
Weight loss dramatically improves outcomes. Every pound lost equals four pounds less knee stress. Even 10-pound loss shows measurable benefit. Studies show overweight patients who lost 5% body weight had 35% better PRP results.
Specific exercises during recovery enhance cartilage remodeling. Isometric strengthening weeks 1-2, progressive resistance training weeks 3-6, and gradual return to impact activities after week 8 shows optimal results.
Addressing biomechanical issues prevents re-injury. Gait analysis often reveals compensations causing excessive knee stress. Custom orthotics or movement retraining protects your investment.
Some benefit from combination approaches. Adding hyaluronic acid to PRP (creating a "cellular matrix") shows enhanced results in some studies. Combining with specific supplements (glucosamine, chondroitin, collagen peptides) may provide additional benefit.
What to Expect Realistically
PRP isn't magic. Understanding realistic outcomes ensures satisfaction.
Most patients experience 60-80% pain reduction. Complete pain elimination is possible but not guaranteed. Function typically improves more than pain—you'll do more even if some discomfort remains. Results develop over 3-6 months, not immediately. Patience is required.
Athletic activities often resume at modified levels. The runner might switch to cycling plus occasional runs. The tennis player might play doubles instead of singles. Quality of life improves dramatically even if elite performance doesn't return.
Maintenance is typically needed. Annual or biannual injections preserve gains. This isn't failure—it's managing a chronic condition successfully.
Taking Action Before It's Too Late
The key message from research is timing. Early intervention with PRP shows dramatically better results than waiting until severe damage occurs. Yet most people wait, hoping it improves or fearing they're "too young" for treatment.
Every month of delay means more cartilage loss, more compensatory damage, and reduced regenerative potential. The knee pain you're "managing" is actually progressive joint destruction.
Don't let age assumptions limit you. Treating arthritis at 40 isn't premature—it's preventive. Waiting until 60 for surgery isn't patience—it's accepting two decades of limitation.
To determine if PRP could help you avoid or delay knee surgery, message our sports medicine team on WhatsApp with details of your symptoms and any imaging results. We'll provide honest assessment of whether regenerative treatment could restore your active lifestyle. Because the best time to save your knees is before they're beyond saving.
