Platelet-rich plasma therapy: Most frequently asked questions
Platelet-rich plasma therapy, or PRP injection, is a relatively new treatment for common musculoskeletal diseases such as arthritis and tendonitis. However, there are so many practitioners offering different types of PRP. As a person who is thinking about Platelet-rich therapy for arthritis or tendonitis, which one do you choose? And does a more expensive [...] The post Platelet-rich plasma therapy: Most frequently asked questions appeared first on Sport Doctor London.
Platelet-rich plasma therapy, or PRP injection, is a relatively new treatment for common musculoskeletal diseases such as arthritis and tendonitis. However, there are so many practitioners offering different types of PRP. As a person who is thinking about Platelet-rich therapy for arthritis or tendonitis, which one do you choose? And does a more expensive system mean a better result? So, this blog will answer the most frequently asked questions on PRP.
What is Platelet-rich plasma therapy?

Put simply, PRP is a blood sample with a higher concentration of platelets. We obtain PRP from your blood. Blood is centrifuged so the heavier cells, such as white and red cells, move to the bottom. The top part of the sample contains plasma with a high concentration of platelets. These platelet cells have a high concentration of growth factors, communicating with other cells in the joint or tendon to reduce inflammation.
Which PRP system is best?
Not all PRP systems are the same. For example, some designs have a platelet concentration of 2-4X with low white cells. Other methods contain a higher concentration of platelets up to 8X with a higher concentration of white cells. Although studies continue, we think a platelet concentration of 3X with low white cells is better for knee arthritis. In comparison, a higher concentration of 6-8X with increased white cells is better for tendonitis.
What is the ideal platelet-rich plasma therapy?
We don’t know. However, it is essential to use a system with a CE marking of 2B. A CE mark is a certification that the products meet a certain standard of safety and sterility. Most large companies developing PRP use a CE marking of 2B. However, some smaller companies developing cheaper PRP don’t have this certification. Therefore, you should ask your doctor about the CE marker for the PRP you are considering using.
Does Platelet-rich plasma therapy work?
Yes, but not for all conditions.
PRP is effective for the following conditions:
- Knee arthritis: We have 23 RCT trials showing PRP is better than placebo of other injectables.
- Tennis elbow: A review of studies shows benefits compared to cortisone or placebo, but not all studies are positive.
- Plantar fasciitis: 9 RCTs show PRP is better than cortisone for heel spurs or plantar fasciitis.
- Gluteus medius tendonits or greater trochanteric syndrome. There is one good RCT showing PRP is better than cortisone.
In addition, there is increasing evidence that PRP is better than cortisone for rotator cuff tendonitis, although we need more studies.
Is PRP injection safe?

Yes. Given we are using your blood, there is little chance of a severe adverse effect. The risk of infection is much less than other injectables, such as hyaluronic acid or cortisone.
Does PRP regenerate cartilage or tendons?
No. Despite the hype, there is no evidence that PRP or any other injectable (stem cells, hyaluronic acid) regenerates your joints or tendons. Instead, they work by improving the environment of the joint or tendon so you feel less pain and can exercise more.
How long does PRP take to work?
Generally, we think that PRP takes 4-6 weeks to start working. In addition, we recommend more than one injection – ususally 2-3 injections every 2-4 weeks.
How to prepare PRP for knee injection?
Generally, we suggest little preparation but recommend the following:
- Hydrate with fluids (1-2L) on the day of the procedure
- Stop all simple anti-inflammatory medications such as ibuprofen at least a week before the procedure and for two weeks post-injection.
How long does a PRP treatment last?

Studies suggest the PRP effect lasts up to 12 months, perhaps longer. However, some studies, such as PRP in greater trochanteric syndrome, have shown a longer-term impact of up to 2 years.
Cost of Platelet-rich plasma therapy
PRP therapy can be expensive. But higher cost does not necessarily mean it will be more effective. Generally, PRP injections in London cost £350 to £1000 per injection.
Dr. Masci offers PRP injections for a cost-effective price from £375 to £475 per injection.
Alternatives to Platelet-rich plasma therapy:
Hyaluronic acid
Hyaluronic acid is a naturally occurring substance found in joints, ligaments, and tendons. We know that hyaluronic acid reduces inflammation and stops the breakdown of cartilage.
Evidence suggests that hyaluronic acid injections such as Durolane improve pain and function in knee arthritis. In addition, high molecular weight hyaluronic acid has a better effect than medium to low molecular weight.
Cortisone
Cortisone is a potent anti-inflammatory that reduces pain and swelling in arthritis and tendonitis. Generally, we suggest limiting cortisone injections for inflamed joints from arthritis because cortisone hurts cartilage and tendon structure.
Stem cells
Stem cell injections have become popular in the last five years. However, there is very little evidence to suggest that stem cells are better than other injectables, such as PRP. In addition, a recent study suggested stem cells were not better than saline for knee arthritis.
Arthrosamid

Arthrosamid is a non-degradable hydrogel that attaches to the lining of the joint. We think that Arthrosamid reduces pain by decreasing inflammation produced by the synovial lining.
Although Arthrosamid has been shown to reduce pain in knee arthritis, we need longer-term data before we can offer it to patients as our first injection option.
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, you should avoid PRP if you have been diagnosed with a blood disorder such as leukemia or lymphoma.
Does PRP treatment hurt?
It shouldn’t be. Blood extraction from the forearm or elbow is simple. Injeciton of PRP into a joint or tendon is better tolerated with ultrasound guidance. However, as local anesthetic should not be used, the injeciton can be a little more painful than other injections.
After the injection, it is important to rest the joint or tendon for at least a week. If needed, you should also take painkillers such as paracetamol and/or codeine. You should avoid anti-inflammatories such as ibuprofen.
Generally, we estimate that 10% of patients get a short-term flare after PRP injections – more common in tendons than joints.
Platelet-rich plasma therapy contraindications
Generally, PRP is well tolerated. However, there are specific contraindications to PRP, including:
- Blood cancer such as lymphoma or leukemia
- Active cancer on chemotherapy
- Blood disorders causing reduced platelet count, such as thrombocytopenia
- Pregnancy
- Chronic use of anti-inflammatory or blood-thinning drugs such as aspirin or ibuprofen
- Suspected septic arthritis or infection
- Injecting into a joint replacement
Does PRP regenerate cartilage or tendons?
No. We have no evidence that PRP regenerates cartilage or tendon structure. However, unlike cortisone, PRP does not harm tissue structure.
Does Asprin hurt platelet-rich plasma therapy?
Yes. Aspirin will inactivate platelets and reduce the growth factor effect at the time of the injection. Therefore, we think Asprin causes a reduced PRP effect. However, Warfarin and Apixaban do not affect platelet function and can be used.
We suggest stopping anti-inflammatories such as Asprin and ibuprofen about one week before and up to two weeks after your last PRP injection.
Do we use local anesthetic with PRP injections?
We think local anaesthetic is cytotoxic. So, in theory, mixing local anesthetic with PRP might negate the positive effects of PRP. In practice, you should limit the amount of local anesthetic you use for PRP injections.
What are rehab guidelines post-PRP injection?
It depends on the structure and pathology injected. However, generally, we suggest avoiding impact activity in the large weight-bearing joints for a week. For tendons, you need to be a little more conservative and suggest re-engaging with strengthening after 10 days and a graded return to running after 4 weeks.
Final word from Sportdoctorlondon regarding Platelet-rich plasma therapy
Platelet-rich plasma treatment has shown promising results in certain musculoskeletal conditions, such as knee arthritis, tennis elbow, and plantar fasciitis. However, it is not the panacea for all states and does not regenerate the cartilage or knee.
Related conditions:
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