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What is the big deal about PRP?
PRP is not a new treatment modality! It has been used by various medical specialties since at least 1950s. The “rich” part of the term means that there are more platelets in the mix as compared to what is normally found in circulating blood.
How does PRP work to eliminate foot and ankle pain?
The work of the repair and inflammation reduction in a complex process that is accomplished primarily by Platelets. These are the molecule that constantly circulate in the blood and are responsible for blood clotting at the site of injury. They help us not to bleed out when a blood vessel is damaged and blood is spilling out. They accomplish the clotting action by releasing chemical signals which are important in clot formation and in healing. PRP concentrates platelets and delivers them at high concentration to injured tissue to start the process of healing and repair.
What is the procedure for collecting of PRP?
The process of platelet isolation involves collection of a blood sample from peripheral circulation (usually an arm is used). Once the blood is collected into a special tube, the sample is transferred the centrifuge and spinning of blood is initiated. This spinning process separates the blood into layers. The spinning occurs at about 1200-1500 RPMs. When the spinning cycle is complete, the red blood cells and white blood cells should be separated from platelets. As RBC and WBC are heavier than platelets, the tend to concentrate on the bottom of the tube. This allows for easy platelet rich plasma removal from the collection tube.
Research shoes that in addition to Platelets themselves, the isolated plasma has other growth factors and signal molecules:
EGF – stimulates fibroblasts to secrete collagenases which are important in tissue repair and remodeling. It also encourages growth and division of skin cells like keratinocytes and fibroblasts
TGFβ1 and TGFβ2 – promote growth of new blood vessels, increase collagen production
VEGF – stimulates growth of new blood vessels during tissue hypoxia (low oxygen levels)
FGF – promotes new skin formation via endothelial cell, fibroblast, and keratinocyte migration into area of tissue injury
Platelet-derived growth factor (PDGF) – enhances migration of immune cells and skin cells, as as promotes collagen synthesis.
Why do some people improve and others do not improve with PRP injection?
There are different manufacturers of the PRP system with different protocols for spinning time, blood volume collected, number of residual red and white blood cells mixed with platelets, and use or lack of use of thrombin (enzyme in plasma the causes blood clotting). Of course, patient’s health contributes to the quality of the platelets and growth factors as well. These include age, conditions influencing platelet health, use of drugs that interact with platelets like aspirin, immunological conditions like diabetes, etc.
What are the side effects of PRP injection?
1. Infection
There are very few side effects and most of them do not have to do with the PRP itself but instead with the way it is administered. Platelet rich plasma is obtained from patient’s own blood, so there is no risk for bacterial or viral infection to develop…unless one already has those organisms circulating in the blood sample collected.
Sterility is essential when collecting, transferring, processing and then administering blood specimen. If sterility is broken, then infection may result. That is why disposable comprehensive all-inclusive kits tend to be very helpful in limiting contamination during the preparation process.
If infection develops, one will need treatment that will depend on the extent and type of infection. Sometimes a few days of antibiotic pills can resolve the problem. However, for more extensive and deep infections, intravenous antibiotics as well as surgical intervention may be required.
2. Tumor development—it’s hypothetical
To date, there is no evidence that shows that platelet rich plasma injections result in tumor formations.
It may be hypothetically assumed that therapeutic growth-factor concentrates in PRP could act more as promoters than as initiators of tumor formation and carcinogenesis.
So, if you have history of cancer or currently have cancer, the data points to avoid platelet rich plasma use.
3. Pain
The level and duration of pain associated with PRP injection is very variable because of variety of application locations, technique used, and volume injected. For example, injection into a joint space should be much less painful than injection into muscle or fascia. This is because joints tend to expend as they get filled with fluid without much residence, where is muscle and fascia tend to be much tighter and have greater resistance coefficient. With stretch and pressure receptor activation, pain is increased.
There are a few ways to decrease the pain of the injection. One is to administer local anesthetic around the area of PRP injection prior to PRP administration. This can lessen the pain. Another way is to decrease the speed of the injection to allow for gradual stretching of the tissue. Using smaller gauge needles can be of help. Using distracting modalities like a vibration device over the nerve supplying sensation to injection area could alleviate the pain as well.
How long does it take for PRP to start working?
This is very individual and depends on what is being treated as different tissues like bone, cartilage, joints, connective tissue and skin all renew and regenerate at different rates.
How effective is PRP?
PRP effectiveness closely correlates with where it is applied and how it prepared. Thus, it is difficult to establish its effectiveness with any degree of certainty. In fact, there are some studies that reveal that too high of PRP concentration may be detrimental to healing as it may release too many inflammatory cells interfering with healing. If PRP is mixed with white blood cells, the inflammation level may also be too high for healing. On the other hand, some authors state that white blood cells have antibacterial effect and may promote growth factor release. Mixing of PRP with red blood cells may promote platelet activation. Another group of researchers noted that mixing of PRP with RBCs causes problems with platelet aggregation.
Articles discussing improvement in joint pain and cartilage regeneration are showing promise, at least in terms of pain and stiffness reduction and functional improvement post injection course.
Can you exercise after PRP injection?
Most of the patients receiving PRP injections are able to return to sport activity within several days post injection. The return to activity is limited by the level of pain due to bruising created by mechanical act of injection of fluid. There is nothing in PRP itself that would preclude one from returning to exercise program. On the other hand, PRP does take longer than, for example, anti-inflammatory injection to produce a significant pain relief because the injection is not primarily anti inflammatory and pain reducing. It is, instead, intended to produce tissue repair and remodeling. This could explain why both PRP and steroid injection tend to work equally well for conditions like plantar fasciitis. However, those who had PRP injection tend to stay pain free much longer.
What Foot and Ankle conditions can PRP treat?
I do not recommend the use of PRP as first line of therapy as, at this time, the results are completely predictable or reproducible. The reasons for this are clear based on PRP preparation differences described above.
Achilles tendon disorders
Achilles tendon injuries take a long time to repair even in healthy individuals. This is a complex tendon which may develop problems in different areas requiring different rehab approaches and different surgical interventions.
Here is a short selective list of what may go wrong:
1. Acute or chronic tear
2. Insertional versus non-insertional tendon injury
3. Painful bursa may form at tendon insertion
4. Calcifications may form in the tendon substance
5. Paratenon (tissue around tendon) may become inflamed
6. Muscle-tendon junction may develop tears
Prolonged healing is due to poor supply of blood to this area which extends healing time. Achilles tendon surgery frequently requires extensive rehabilitation period that starts with the use of casts/immobilizing boots and non-weight bearing. The patient is then progressed to a weight bearing device with heel lift to keep tension low on the repaired tendon. Then, the tension is gradually increased. This describes best case scenario. Of course, if there is a complication like incision site non-healing, the process can be delayed by weeks.
Thus, PRP injection serves as a potentially good alternative to surgery as it may reduce or eliminate symptoms where surgery can be delayed by a significant amount of time or even avoided all together. Of course, one would still be immobilized after PRP injection but for a very short period of time. I usually recommend adjustment in activity for at least 7 days to help with pain and inflammation reduction. In the end, if PRP fails to help, it will not hurt one’s chances of undergoing surgery. In addition, for individuals who are not candidate for surgery due other health issues may find that PRP is the only treatment modality outside of physical therapy and immobilization that is available to them.
Unlike, injections for plantar fasciitis, Achilles tendon should not be injected with steroid solution, as this has significant risk for tendon rupture due to tendon fiber weakening.
Plantar fasciitis
This is the most common cause of heal pain. I like to describe is a bruising of and around heel bone’s insertion of plantar fascia. Plantar fasciitis is an aggregate term that can describe a chronic or an acute injury. The sooner this condition is treated, the faster the recovery will be. Those patients that ignore the pan and injury frequently end of with pain that requires multimodal therapy to include orthotics, anti-inflammatory modalities, offloading, cortisone injections, physical therapy, cryotherapy, etc. When treated right away with decrease in activity and inflammation reduction, the condition is resolved while in its acute stage with one to two weeks. With chronic inflammation, plantar fascia may become thickened, scarred, perpetually inflamed.
The most common therapy that works predictably well is a cortisone injection. This is one of the most painful injections that can be administered around foot and ankle. Unfortunately, there are only few things that can be done to lessen the pain of the injection. These include, use of cold spray on the skin to decrease sensitivity at injection site. Cold spray of course does not do anything to decrease the pain of mechanical stretching of tissue deep to the skin. Application of vibration signal proximal to injection site can also decrease the discomfort. Lastly, adding sodium bicarbonate to the local anesthetic like lidocaine prior to injection lowers the acidity of that medicine. Pain receptors respond more acutely in acidic environment, thus decreasing the acidity of the injected medicine should decrease the pain at injection site.
As previously mentioned, both PRP and steroid injection tend to work equally well for conditions like plantar fasciitis. However, studies show that those who had PRP injection tend to stay pain free much longer.
Cartilage Erosion in joints and Osteoarthritis
Osteoarthritis or destructive joint changes are very common in active individuals. Outside of surgery, treatment options include cortisone injections, hyaluronic acid injections, saline injections, and of course PRP injections.
None of these modalities truly lead to regeneration of cartilage but do help with pain and inflammation reduction through different mechanisms. All of these require repeat administrations with progressively reduced positive effect.
Cortisone shots-decrease inflammation and thus pain. However, frequent exposure can actually slow down development of new cartilage
Hyaluronic acid—this is basically a non-reactive lubricant that decreases grinding in the joint and allows for improved range of motion and pain reduction.
Saline injection: unclear why this is helpful. Some indicate that the benefit could be due to placebo effect, while others state it breaks down adhesion and widens the joint space
Wound healing
There is significant amount of data showing improved wound healing outcomes with PRP use. Unfortunately, most of these studies involve small number of people studies and were sponsored by companies manufacturing PRP prep kits. This, of course, introduces bias into research. However, if the standard of care in wound care has been tried with poor outcome, use of PRP should be considered to facilitate wound closure. It must not be, however, first line therapy per currently poor scientific support data.
In summary,
Platelet rich plasma is not a new modality and has been found to be helpful in treatment of many foot and ankle orthopedic and skin conditions. Unfortunately, no one can predict how helpful it really is because of poor scientific support data.
Notwithstanding, many scientific trials are currently underway to clarify and guide the specifics of this therapy. If one has tried other treatment modalities but did not improve, one should absolutely try PRP therapy as it has many potential benefits and few downsides. One word of caution is the hypothetical potential for tumor formation in those individuals who already developed these tumor cells.
Remember, prevention of injury is the best medicine!
Please share this post if you found it helpful!
Until next time….happy healing!
Resources:
Platelet–rich plasma in the foot and ankle.
Henning PR, Grear BJ.
Curr Rev Musculoskelet Med. 2018 Dec;11(4):616-623. doi: 10.1007/s12178-018-9522-z. Review.
Amin I, Gellhorn AC.
Phys Med Rehabil Clin N Am. 2019 May;30(2):439-449. doi: 10.1016/j.pmr.2018.12.005. Epub 2019 Mar 11. Review.
My name is Dr. Marat Kazak. I have been working as a professional Podiatrist serving Northern California community since 2014. My extensive medical and surgical knowledge combined with an ongoing curiosity to learn about the latest trends define my success in the field of foot, ankle and leg medical and surgical care.
The goal of this website is to give you the tools to better care for yourself, to dispel medical myths, and to empower you with information to save time and money! If you are looking for an answer on foot and ankle pain, this is the place to find it. If you do not see your topic of interest covered, please send me a message and I will do my best to discuss it thoroughly in my next upcoming post.
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