How Long Does Platelet-Rich Plasma Last in the Knee?

knee injection

-by Dr. Maria Karipidis Pouria, MD, FAAP, CAQ sports medicine, FACP 

Patients experiencing chronic knee pain that has not improved with conservative treatments such as over-the-counter medication, a home exercise program, physical therapy and occasional cortisone injections, are left feeling frustrated and unaware of further alternatives to invasive surgery or pain medications. The emergence of regenerative medicine procedures has revolutionized how various conditions and injuries are treated. 

Dr. Karipidis Pouria with a sample of blood ready to be spun in the centrifuge.

Treating Knee Pain with Platelet-Rich Plasma

Platelet-rich plasma (PRP) is one procedure that has robust data in treating knee pain and promoting healing. PRP is performed as an office-based procedure where a sample of your blood is obtained, similar to a lab draw. The blood is spun at high speeds in an FDA-approved device called a centrifuge, which separates the plasma and platelet portion that is concentrated with cytokines, growth factors, proteins, and signaling molecules to promote healing and tissue regeneration. This is then injected into the area of injury or pain. The entire sterile procedure is performed under precise ultrasound guidance in under an hour. 

Unlike invasive surgery, where the downtime for recovery may be several weeks to months, PRP does not require a hospital stay, anesthesia, or sutures, and most patients return to work within a few days and their activities within a week. 

Widespread Utilization of PRP

Once considered experimental, PRP injections were only available in clinical trials and to top level athletes such as Tiger Woods, Kobe Bryant, Alex Rodriguez, and Rafael Nadal to help them heal faster from their injuries. Treatments have now become widespread and utilized in the college athlete, the weekend warrior, and for those limited in their activities from osteoarthritis.

The Data Surrounding PRP

One-year data from multiple randomized controlled trials revealed that PRP injections are effective and can provide clinically significant functional benefit for one year in patients with mild to moderate knee osteoarthritis. A meta-analysis of 20 randomized controlled trials that compared PRP to hyaluronic acid injections concluded that PRP was superior to hyaluronic acid injections in terms of long-term pain relief and functional improvement.

The ongoing body of literature continues to show that PRP injections are better in both short-term and long-term pain relief in comparison to placebo, corticosteroid and hyaluronic acid injections.  We believe that this sustained relief is because PRP contains a large amount of growth factors that provide tissue healing, remodeling and pain relief. By introducing these growth factors into the knee joint, the toxic and inflammatory environment seen in osteoarthritis can be reset to a more neutral environment to slow the progression of the disease. 

How Is Pain Relief Maintained with PRP?

Patients with knee osteoarthritis and complex athletic injuries may benefit from a “booster” PRP injection at one year to keep the internal environment of the knee as healthy as possible and reduce the accumulation of inflammatory markers in the joint.  Most studies reveal that patients with mild to moderate arthritic change can get up to a year of benefit from a PRP injection.

A recent systemic review conducted in March 2022 in the Journal of Arthroscopy evaluated 79 studies and over 8,700 patients and concluded that PRP showed the lowest WOMAC pain scores at one year follow up. WOMAC scores measure pain, stiffness, and function with lower numbers signifying better outcomes.

The current consensus is to proactively undergo a PRP booster injection at approximately one year or sooner if symptoms warrant.

A personal consultation with Dr. Karipidis is the first step in learning more about your condition and whether PRP injections are right for you. Call our office at 585.244.1506 for more information or to schedule an appointment.

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