PRP Injection for Knee Pain

Knee pain affects one in four adults in the UK, with numbers rising as our population ages. For those seeking alternatives to knee replacement surgery or finding limited relief from conventional treatments, platelet-rich plasma injections offer a regenerative approach backed by growing scientific evidence.

How PRP Works for Knee Conditions

The knee joint is particularly suited to PRP therapy due to its accessible location and the prevalence of conditions that respond well to growth factor stimulation. When injected into the knee, PRP releases growth factors that reduce inflammation in the synovial lining, stimulate cartilage cell activity, and improve the quality of joint fluid.

A 2023 meta-analysis in Arthroscopy Journal, analysing 26 randomised controlled trials with over 2,000 patients, found PRP superior to hyaluronic acid and corticosteroid injections for knee osteoarthritis at 12-month follow-up. The study noted particular effectiveness in patients under 60 with mild to moderate arthritis.

Specific Knee Conditions Treated with PRP

Knee Osteoarthritis

Early to moderate knee osteoarthritis responds particularly well to PRP. The International Cartilage Repair Society now includes PRP in their treatment algorithm for knee arthritis. Studies show that patients with Kellgren-Lawrence grades 1-3 arthritis experience the best outcomes, with average pain reduction of 50-70 percent at six months.

The mechanism involves PRP's anti-inflammatory effects combined with its ability to stimulate chondrocytes, the cells responsible for maintaining cartilage. While PRP cannot regrow lost cartilage, it can slow degeneration and improve the health of remaining tissue.

Meniscal Tears

For degenerative meniscal tears, common in people over 40, PRP offers an alternative to arthroscopic surgery. Recent evidence suggests that many meniscal surgeries provide limited long-term benefit, making regenerative options increasingly attractive. PRP can reduce inflammation around the tear and potentially promote healing in tears located in the vascular zone of the meniscus.

Patellar Tendinopathy

Commonly known as jumper's knee, this condition affects the tendon connecting the kneecap to the shinbone. Traditional treatments often provide temporary relief. Studies show PRP can stimulate tendon healing, with 70-80 percent of patients returning to sport after treatment.

The Treatment Protocol

Successful PRP treatment for knee conditions typically follows a structured approach. Most protocols involve 1-3 injections spaced 2-4 weeks apart. Research suggests that multiple injections may provide better outcomes than a single injection, particularly for osteoarthritis.

The injection technique matters significantly. Ultrasound guidance ensures accurate placement of PRP into the joint space or specific tissue. For osteoarthritis, intra-articular injection is standard. For tendon or ligament issues, the PRP is placed directly at the injury site.

Pre-treatment preparation includes stopping anti-inflammatory medications one week before treatment, as these can interfere with the healing response. Post-injection, a structured rehabilitation programme enhances outcomes. This typically includes initial rest, gradual mobilisation, and progressive strengthening exercises.

Comparing PRP to Other Knee Treatments

Versus Steroid Injections

While corticosteroids provide faster initial pain relief, typically within 48 hours, their effects rarely last beyond 3 months. PRP shows slower onset of benefit but longer-lasting results. A landmark study in the American Journal of Sports Medicine followed patients for two years, finding PRP superior to steroids at every time point after three months.

Importantly, repeated steroid injections can accelerate cartilage breakdown and weaken tendons. PRP, conversely, may have protective effects on cartilage and promotes tissue healing rather than merely masking symptoms.

Versus Hyaluronic Acid

Hyaluronic acid injections (viscosupplementation) work by improving joint fluid quality. While beneficial for some patients, studies consistently show PRP provides superior and longer-lasting results. The cost difference is minimal, but PRP offers the advantage of addressing the underlying tissue damage rather than just improving lubrication.

Versus Surgery

Arthroscopic knee surgery for degenerative conditions has fallen out of favour following studies showing limited benefit over physiotherapy alone. PRP provides a less invasive option with no surgical risks, no recovery downtime, and the possibility of avoiding or significantly delaying knee replacement.

Realistic Expectations and Success Rates

Understanding realistic outcomes helps patients make informed decisions. For knee osteoarthritis, approximately 70 percent of patients experience meaningful improvement, defined as at least 30 percent pain reduction and functional improvement. Results typically last 12-24 months, with some patients maintaining benefits longer.

Factors influencing success include age (better results under 65), arthritis severity (mild to moderate responds best), body weight (BMI under 30 shows better outcomes), and activity level (moderately active patients do better than sedentary or highly active individuals).

Not everyone responds to PRP. Approximately 20-30 percent of patients experience minimal benefit. These tend to be patients with severe, bone-on-bone arthritis, significant knee deformity, or inflammatory arthritis conditions like rheumatoid arthritis.

Recovery and Rehabilitation

The first week after injection involves relative rest and ice application. Most patients can walk immediately but should avoid strenuous activities. Weeks 2-4 involve gentle range-of-motion exercises and gradual return to normal activities.

By week 6, most patients begin strengthening exercises. This rehabilitation phase is crucial for optimal outcomes. Studies show that patients who follow structured physiotherapy programmes after PRP achieve better results than those who don't.

Full benefits typically manifest by 3 months, though some patients continue improving up to 6 months. Athletes can usually return to sport between 3-4 months, depending on their specific condition and sport demands.

Making the Decision

PRP for knee pain makes most sense for patients who have tried conservative treatments without adequate relief, want to avoid or delay surgery, have mild to moderate arthritis or tendon/ligament injuries, and are willing to commit to the rehabilitation process.

The treatment is particularly valuable for active individuals who want to maintain their lifestyle without the downtime of surgery. For younger patients with early arthritis, PRP may help preserve the joint and delay the need for eventual replacement.

Ready to determine if PRP could help your knee pain? Book a free consultation via WhatsApp to discuss your specific condition. Send your recent MRI or X-ray images for personalised assessment and realistic outcome projections based on your individual factors.