What is Platelet Rich Plasma?

Platelet Rich Plasma or PRP

Platelet-rich plasma (Abbreviation: PRP) is a growing and robust therapeutic option in the treatment of musculoskeletal conditions. PRP is blood plasma that is rich in platelets. As a concentrated source of autologous platelets, PRP contains (and releases through degranulation) several different growth factors and other cytokines that stimulate healing of bone and soft tissue.

Platelets are a specialized type of blood cell involved in injury healing. Platelets also contain large reservoirs of natural growth factors that are essential for the cell recruitment and multiplication involved in wound healing.

The normal concentration of platelets circulating in our blood is 200,000 per microliter. Current evidence suggests that platelet count in Platelet Rich Plasma should be near or exceed 1,000,000 platelets per microliter which is a concentration of 5x.

PRP is made in the office using a centrifuge that separates the blood components and allows us to discard unwanted elements from the blood and to keep the platelets, growth factors, cytokines, and plasma that are used for PRP. The centrifuge takes less than 10 minutes to concentrate the platelets after blood is drawn from the patient.

History of PRP

The application of PRP has been documented in many fields. M. Ferrari first promoted PRP in 1987 as an autologous transfusion component after an open heart operation to avoid homologous blood product transfusion. PRP is being studied in orthopedics, sports medicine, dentistry, otolaryngology, neurosurgery, ophthalmology, urology, wound healing, cosmetic, cardio-thoracic and maxillofacial surgery. 

The initial popularity of PRP grew from its promise as a safe and natural alternative to surgery. PRP advocates promoted the procedure as an organically based therapy that enabled healing through the use of one’s own natural growth factors. In recent years, scientific research and technology has provided a new perspective on platelets. Studies suggest that platelets contain an abundance of growth factors and cytokines that can affect inflammation, postoperative blood loss, infection, osteogenesis, wound, muscle tear and soft tissue healing. Research now shows that platelets also release many bioactive proteins responsible for attracting macrophages, mesenchymal stem cells and osteoblasts that not only promote removal of degenerated and necrotic tissue, but also enhance tissue regeneration and healing. 

Musculoskeletal practitioners began using PRP for tendinopathy in the early 1990s. The popularity of PRP grew as physicians began to see clinical results in concentrating a patient’s own blood factors.

There have been few controlled trials to prove the efficacy of PRP so physicians have relied primarily on anecdotal or case reports. Of the existing clinical trials, the sample sizes tended to be too small to allow for generalization of findings. Moreover, lack of concensus on technique, number of injections, spacing of injections, number of platelets, concentration of platelets over baseline, with or without leukocytes in the injection, exogenous activation of injected platelets and even a definition of appropriate candidates for the procedure are lacking and in need of further definition and evaluation.

Recently, however, there has been an emerging literature on the beneficial effects of PRP for chronic non-healing tendon injuries including lateral epicondylitis, plantar fasciitis and cartilage degeneration. 

Growth Factors and Cytokines in PRP

Below are the more important growth factors and cytokines that stimulate tissue healing.

• Platelet Derived Growth Factor (PDGF)
• Fibroblast Growth Factor (FGF)
• Vascular Endothelial Growth Factor (VEGF)
• Interleukin 8 (IL-8)
• Transforming Growth Factor Beta (TGF-b)
• Insulin like Growth Factor 1, 2 (IGF-1,2)
• Epidermal Growth Factor (EGF)

How PRP Works

After the body part being treated is injected with PRP, there is immediate activation of the plasma resulting in rapid growth factor release, with 90% of the growth factors being released in the first ten minutes. The other 10% of growth factors can take up to a week to be activated.

Once activation has occurred at the injection site, release of growth factors initiates an inflammatory response that lasts approximately 3 days. Fibroblasts accumulate at the site of injection, which marks the beginning of the proliferative phase of healing that lasts several weeks. After that, remodeling occurs to the collagen matrix that was laid down by the fibroblasts. This remodeling phase that leads to the formation of mature tissue lasts about 6 months. It takes all three phases for new tissue to form and provide long-term stability to tissue. 

It may be necessary to have more than one PRP injection to treat a single condition to get maximal results.

Here is a video from John Hopkins Musculoskeletal Center.

Clinical Conditions for using Platelet Rich Plasma

Platelet Rich Plasma is indicated for subacute and chronic conditions. Healing of injuries and musculoskeletal conditions slows or stops after 6-12 weeks after an acute injury. If a patient has had no improvement for over 6 weeks, it is possible the healing phase has arrested or stopped.  PRP can help jumpstart the healing process once again in these individuals.

PRP is being studied and used for many orthopedic conditions. There are several level 1 studies published showing that PRP is a better treatment than steroid or hyaluronic acid injection for knee osteoarthritis. PRP has now been used and studied for virtually every joint, tendon, and ligament injury in orthopedics. PRP has also been shown to be effective in treating back pain from various conditions such as disk disease, or facet arthrosis.

Below are more specific musculoskeletal conditions for which PRP can be useful. PRP is also used to treat baldness and during cosmetic procedures.

Tendonitis (Chronic tendonitis or partial-thickness tears)

• Rotator cuff
• Biceps
• Golfers/Tennis elbow
• Tendonitis around the thigh (Gluteus medius, hamstring, piriformis syndrome)
• Patellar or quadriceps tendonitis
• Tendonitis around the ankle (Peroneal, Tibialis posterior)
• Achilles tendonitis
• Plantar fasciitis

Ligament Injury

• Ulnar collateral ligament injury of the elbow
• Medial collateral ligament injury of the knee

Degenerative Joint Disease

• Knee osteoarthritis
• Hip osteoarthritis
• Ankle osteoarthritis
• Shoulder osteoarthritis
• Elbow osteoarthritis
• Wrist osteoarthritis
• Symptomatic articular cartilage injury

Fracture Care

• Delayed union or nonunion fractures

Preparing for Your PRP Injection

• Notify your physician if you are on any blood thinners or antiplatelet drugs. These include Aspirin Plavix, Heparin, Lovenox, Coumadin, Eliquis, Xarelto, Pradaxa.
• Avoid consistent use of NSAIDs (ibuprofen, naproxen, diclofenac, etc) within 48 hours of the procedure.
• Avoid a cortisone injection at the treatment site within one month of the procedure. Some physicians say even three months.
• Avoid oral corticosteroids within 2 weeks of your procedure.
• Avoid tobacco use (hinders blood flow critical to healing)

How Safe Is PRP?

PRP is very safe. Since PRP is derived from your own blood there are less risks than with injections using medications such as cortisone. Complications are related to the procedure itself and not the PRP.

The risks, complications, and most noted side effects include:

• Pain or soreness to the injection site- which initially increases and can last several days, but gradually decreases with time, usually within 48 hours
• Allergic reaction to any of the substances utilized during the procedure, such as the anesthetic, antiseptic, or dressing. This is usually minor and self-limiting.
• Local bruising or bleeding.
• Nerve injury leading to numbness or weakness which is usually temporary but can be permanent.
• Infection- Most infections will present within 48 hours of the procedure and marked with redness and warmth at injection site, and worsening pain.
• Lack of benefit. Though not a side effect, not all patients will benefit from PRP injections.
• Loss of limb or death –very rare but still possible.

What to Expect After Your Injection

Most patients will have some soreness after the injection that should decrease rapidly. Patients should not take aspirin or other NSAID medications after the procedure because they may block the effect of PRP. Patients can use Tylenol and other pain medications that don’t block the inflammatory process. Patients should refrain from significant physical activity or sports activities for a week after the procedure. Patients are re-evaluated often after the procedure to make sure their recovery process is proceeding according to plan.

What is the Cost of PRP

PRP injections are typically not covered by insurance, which means you will be paying out of pocket for the procedure. PRP injections typically cost about $600. This can vary depending on the complexity of condition being treated and how many body parts are being treated at a single visit.

Is PRP FDA Approved?

FDA stands for Food and Drug Administration. PRP is not a drug, but the equipment used to produce PRP and the injections themselves have been cleared by the FDA. Platelet rich plasma is considered an investigational procedure and has not been officially approved by the FDA for most uses. Since PRP is a substance derived from one’s own blood, it is not considered a drug. FDA clearance means that doctors can prescribe and administer PRP if they believe it’s in the best interest of the patient. However, lack of the FDA approval means that PRP treatments may not be covered by insurance.