Platelet-rich plasma (PRP) has grabbed headlines in recent years for its role in helping some of sports’ biggest stars return to play following injury. It is increasingly common to hear of these athletes having a “blood injection”, but what does this actually do, and more importantly, does it actually work? Blood injections are not just the domain of the athlete though – the procedure is currently very commonly recommended to many people to address a wide-range of orthopaedic conditions, including injuries to the joints, ligaments, tendons and muscles. In fact, this procedure has become so common that is has caused issues with the Medicare funding (but more of that later). In this article we explain more about blood injections and where the science sits at the moment!

What Are Platelet Rich Plasma Injections?

prpspecialties_prpPlatelet Rich Plasma (PRP), Autologous Blood Injections (ABI) or simply “blood injections” are all interchangeable words. The definition of autologous is “obtained from the same individual” so ABI is simply a term for blood that is withdrawn from the same person it is then being injected back into. In this procedure blood is withdrawn from a person (usually from the elbow area), spun in a centrifuge to separate the blood into 3 main components (red blood cells, platelet poor plasma, and platelet rich plasma), and the platelet rich blood component reinjected back into an area of injury or damage. Platelets play a critical role in tissue repair and regeneration because they are rich in growth factor granules, and this forms the theory behind this procedure: inject a substance rich in growth factor granules into an area of tissue damage, under ultrasound guidance to ensure the most damaged area is targeted, and hopefully stimulate a cascade of natural healing. Basically, it’s bathing damaged cells in a concentrated mixture of growth factor cells from your own blood. Sounds great, doesn’t it!

Tendons in particular have been a high focus for PRP injections, due to the high incidence of tendinopathy (tendon damage) in the general population and the known slow rate of tendon healing due to the poor natural blood flow that tendons have. Think of the following problems: rotator cuff tears, tennis elbow, golfers elbow, achilles tendinopathy, patella tendinopathy (or jumpers knee) and hip bursitis (which in reality is mostly an issue of the gluteus medius tendon): have you ever know someone to have one of these problems for a few weeks?

When any of these large and important tendons are damaged, you can guarantee three things – pain, loss of function, and a LONG healing time!

The use of PRP has proliferated in recent years especially in sports medicine where injured athletes are eager to recover faster and return to their sport. Despite its rising popularity, PRP remains a costly treatment which basically has little scientific evidence to support its use. This combination – high popularity, increased referrals, high cost, and limited evidence – has actually resulted in Medicare recently withdrawing its rebate for PRP injections, making the procedure even more expensive!

Do PRP Injections Work?

prp-3This is where it gets interesting, There are a few studies out there that seem to indicate that PRP injections can make a difference on tissue healing. However a few positive studies do not mean we have a new miracle cure for soft tissue injuries. The majority of studies of high quality fail to show a consistent positive effect of PRP injections. The studies also cannot show which tissue responds best to PRP – tendons, ligaments, muscles, or cartilage/joint.  Taken as a whole, the evidence is somewhere between inconclusive and discouraging, and more high quality studies are needed before we can make definitive statements on the benefits and use of PRP injections.

This brings us back to the Medicare point – with such an increase in claims being submitted for PRP injections, and such minimal evidence to support its use and benefits, it is not surprising that rebates have been ceased!

Why Would PRP Work?

At SSPC, we have had many patients referred by doctors or sports physicians for PRP injections, and we’ve seen some great results, mainly in regards to treatment of tendon injuries! As recently as a few weeks ago, we had a patient with chronic Achilles tendinopathy have a single blood injection and be “cured” of his pain, returning to running pain free in the week after the injection.

However this is where “evidence” can be misleading. A sample size of one can prove or disprove anything, but it’s hardly “evidence”. Anecdotally, we would say that our SSPC population would have had a 50% success rate at best with PRP procedures.

There are a few theories on why PRP may be effective:

* Perhaps it does actually work, but we don’t have enough information yet to screen who the perfect patient is, or what the perfect area/tissue is that will respond positively to PRP. The theory of extracting growth cells and releasing them around a damaged area makes perfect sense, we just haven’t seen consistent results to date! So let’s not throw the baby out with the bath water yet!

* Heard of placebo effect? Sometimes if we think something is going to work, and we have a positive attitude to the procedure (it healed Tiger Woods so it must work for me too), then the brain takes over the healing process and creates change. PRP creates a powerful opportunity for placebo effect:

–  People expect injections to be more effective than other means of intervention.

– We are strongly influenced by what elite athletes are doing.

– PRP is both high tech and natural, a rare combination that gives us more hope than other products.

* Maybe natural healing has taken place? Sometimes the extra attention that comes following a blood injection (enforced rest, doing the right exercises, not provoking the pain etc) may have been the stimulus that the area needed to heal?

* The injection process itself creates a bleed which stimulates tissue healing. Even with the dry needling that physio’s do, there is a theory that the tissue damage caused by the penetration of fine needles may just stimulate the body to begin a healing process. So maybe it’s not the blood injected in, it’s the tip of the needle that stimulates healing!

* What about the rest of the rehab process? The back page of The Herald Sun can scream “Paul Chapman’s Hamstrings Fixed With Blood Injections”, and so every suburban footballer with a hamstring problem turns up on our door Monday morning asking about PRP. What these articles neglect to say is that these elite athletes receive hours of physiotherapy, massage, strength and conditioning, and precise rehabilitation programs. There’s a slight chance that the improvement was coincidentally at the time of the injection, or more likely that it is the hours of treatment and rehab, in combination with the injection, that produced results.

Should I Give It A Go?

Well, that’s the million dollar question (or $300 question anyway)! There’s no doubt the hype around PRP definitely came before the science! As we’ve seen over an excruciating few years in the A.F.L, anything being injected should be proven both safe and clinically beneficial before we expose it to the masses.

It seems that PRP’s are safe, and there’s perhaps a little bit of clinical and anecdotal hope, so maybe if all other options are exhausted, it might be worth a try, particularly for chronic tendon problems, and especially with a well-constructed rehabilitation program to complement the injection. We’re definitely sure that it stands a better chance of working than cortisone! But be prepared to spend up to $300 per injection, possibly need 2 – 4 injections over a few months, and maybe still have the pain – food for thought!