Platelet-rich plasma therapy, also known as PRP injection, is a relatively new treatment for common musculoskeletal conditions, including arthritis and tendonitis. But many practitioners offer different PRP treatments — so which would you choose, and does a more expensive system mean a better result? This guide answers the most common questions about PRP therapy.
What is platelet-rich plasma therapy?
PRP is a blood sample with a higher platelet concentration. We take your blood and spin it in a centrifuge so the heavier white and red cells sink to the bottom. The upper plasma layer holds a high concentration of platelets, which carry growth factors that communicate with cells in the joint or tendon to reduce inflammation and aid healing.
Which PRP system is best?
Not all PRP systems are the same. Some produce platelet concentrations of 2–4 times normal with low white-cell counts; others reach up to 8 times normal with higher white-cell counts. Although research continues, we believe a high platelet concentration with a low white-cell count is better for knee arthritis, while a higher concentration (6–8x) is better for tendons. The Arthrex ACP Max system is a second-generation PRP that delivers an adequate platelet dose in a single injection for both arthritis and tendonitis.
What is the ideal PRP system?
We don’t know for sure, but using a system with CE marking 2B is essential. A CE mark certifies that a product meets specific safety and sterility standards. Most large PRP companies hold a 2B CE mark, but some smaller, cheaper systems don’t. Ask your physician about the CE marking of the PRP they use.
Does PRP therapy work?
Yes, but not for every joint and tendon condition. The evidence supports PRP for knee arthritis (23 RCTs show PRP beats placebo or other injectables), tennis elbow, plantar fasciitis (nine RCTs favour PRP over cortisone), gluteal tendonitis / greater trochanteric pain syndrome (one strong RCT favours PRP over cortisone), and rotator cuff tendonitis.
Is PRP safe?
Yes. Because we use your own blood, the risk of a serious adverse effect is minimal, and the risk of infection is lower than with other injectables such as hyaluronic acid or cortisone.
Does PRP regenerate cartilage or tendons?
No. Despite the hype, there’s no evidence that PRP — or any other injectable, including stem cells or hyaluronic acid — regenerates joints or tendons. Instead, it improves the environment of the joint or tendon, so you feel less pain and can exercise more. Unlike cortisone, though, PRP doesn’t harm tissue structure.
How long does PRP take to work?
PRP works gradually, usually over about 4–6 weeks. For arthritis, we typically recommend 1–2 injections; for tendonitis, two injections about two weeks apart. (Second-generation ACP Max delivers the higher dose in a single injection.)
How long does PRP last?
Studies suggest the effect lasts up to about 12 months, sometimes longer. In some conditions, such as greater trochanteric pain syndrome, the benefit has lasted up to two years.
How much does PRP cost?
PRP can be expensive, but a higher cost doesn’t necessarily mean a better result. PRP injections in London generally cost £350 to £1,000 per injection. Dr Masci offers standard PRP at a cost-effective £510 for the first injection and £410 for subsequent injections. He also offers the second-generation Arthrex ACP Max — a double-spin, higher-dose PRP that requires only one injection (rather than 2–3) — for £1,350, including consultation and injection. Review the self-pay fees here.
Alternatives to PRP therapy
Hyaluronic acid is a naturally occurring joint lubricant that reduces inflammation; high-molecular-weight versions, such as Durolane, improve pain and function in knee arthritis and work better than lower-molecular-weight ones.
Cortisone is a potent anti-inflammatory, but we limit its use in arthritis because repeated use can harm cartilage.
Stem cells have grown popular, but there’s little evidence they beat PRP — and a recent study found them no better than saline for knee arthritis.
Arthrosamid is a non-degradable hydrogel that adheres to the joint lining and reduces inflammation; it helps knee arthritis, though we await longer-term data before offering it as a first-line injection.
Other frequently asked questions about PRP therapy
Can PRP therapy cause blood clots?
No. We don’t think PRP increases the risk of blood clots. However, avoid PRP if you have a blood disorder such as leukaemia or lymphoma.
Does PRP hurt?
It shouldn’t. Taking blood from your arm is simple, and a PRP injection is better tolerated under ultrasound guidance. Because we avoid local anaesthetic (it can damage platelets), the injection itself may be slightly more uncomfortable than others. Rest the joint or tendon for at least a week afterwards, and use paracetamol or codeine if needed — avoid ibuprofen. About 10% of people experience a short-term flare, more often in tendons than in joints.
What are the contraindications to PRP?
Blood cancer (lymphoma or leukaemia), active cancer on chemotherapy, a low platelet count (thrombocytopenia), pregnancy, chronic anti-inflammatory or blood-thinning use, suspected infection or septic arthritis, and injecting into a joint replacement.
Does aspirin affect PRP?
Yes — aspirin inactivates platelets and reduces the growth-factor effect, so we think it lowers PRP’s benefit. Warfarin and apixaban don’t affect platelet function and can be continued. Stop anti-inflammatory medications, such as ibuprofen, for about 1 week before and up to 2 weeks after your last PRP injection.
I took ibuprofen after PRP — should I be worried?
It’s not dangerous, but ibuprofen taken before or after PRP can reduce its effectiveness, so it’s best avoided. Try not to take ibuprofen (or other NSAIDs) for at least ten days after your last PRP injection — paracetamol or codeine are better choices for pain in that window.
Do you use local anaesthetic with PRP?
We limit it. Local anaesthetics are cytotoxic (they can harm cells), so mixing them with PRP might reduce their benefit. We numb the skin separately where needed rather than mixing anaesthetic into the PRP.
How many PRP injections are needed?
It depends on the condition: for osteoarthritis, usually 1–2 injections; for tendonitis, two injections 1–2 weeks apart. ACP Max achieves the dose in one.
What are the rehab guidelines after PRP?
It depends on the structure injected. Generally, avoid impact activity in large weight-bearing joints for about a week. For tendons, be more conservative — restart strengthening after about 10 days and a graded return to running at around four weeks.
Final word from Sport Doctor London about platelet-rich plasma therapy
PRP has shown promising results for certain conditions — knee arthritis, tennis elbow, and plantar fasciitis, among them. But it isn’t a cure-all, and it doesn’t regenerate cartilage. Used selectively, under ultrasound, and alongside exercise, it’s a useful option for the right patient.
To discuss whether PRP suits your condition, contact Dr Masci’s team here or call +44 (0) 203 488 0350.
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