Biological Therapy with PRP, or Platelet-Rich Plasma
Have you heard of PRP for treating joint pain or tendon injuries? The acronym stands for "platelet-rich plasma" and refers to a preparation derived from the patient’s own blood.
In recent years, PRP has gained interest within the field of orthopedics as a potential tool for treating certain musculoskeletal conditions. However, it is important to understand how it works, what its limitations are, and why its use must be determined on an individual basis.
What is PRP?
Platelet-rich plasma (PRP) is a preparation obtained from the patient’s own blood. After collection, the blood is processed—typically via centrifugation—to separate its components and yield a portion of plasma with a higher concentration of platelets. Beyond their role in blood clotting, platelets contain proteins and growth factors that participate in the inflammatory response and tissue repair processes.
In orthopedics, PRP is being studied as part of the treatment for certain joint and tendon conditions, with the goal of helping to improve pain and function. Its composition can vary depending on the preparation method, and outcomes depend on the specific condition being treated as well as the individual characteristics of each patient; therefore, PRP should not be viewed as a guarantee of tissue regeneration or a cure for an injury.
How is PRP administered? Learn about the step-by-step process.
Treatment with platelet-rich plasma, or PRP, begins with the collection of the patient’s own blood—a process that can be performed in an outpatient setting (such as a doctor’s office) or in a hospital, depending on the specific case.
The collected blood is then processed to obtain a preparation containing concentrated platelets, which is subsequently applied to the area designated by the physician.
The procedure may vary based on the condition being treated, the preparation method, and the materials used. In general, the steps are as follows:
Medical evaluation and planning
Before the procedure, an assessment is conducted to identify the cause of the symptoms and determine whether PRP is an appropriate option for the specific case.
During this consultation, the patient’s medical history, previous treatments, current medications, and—when necessary—imaging studies are reviewed. The potential benefits, limitations, and risks of the procedure are also explained.
It is important to inform the physician about all medications you are currently taking. Do not discontinue any medication on your own; if any adjustments are necessary, you will be given specific guidance accordingly.
Blood collection
On the day of the procedure, a blood sample is collected from a vein—typically in an upper limb—in a manner similar to how blood is drawn for a conventional laboratory test. The volume of blood collected depends on the system being used and the amount of PRP required for the application.
Centrifugation and preparation of PRP
After collection, the blood is placed into a device called a centrifuge. It spins the tubes at a controlled speed, allowing the blood components to separate.
Through this process, it is possible to obtain a portion of plasma with a higher concentration of platelets. The preparation method may vary depending on the system and protocol used.
Platelets contain substances, including growth factors, that play a role in processes related to the inflammatory response and tissue repair.
Preparation of the area to be treated
While the PRP is being prepared, the patient is positioned appropriately for the procedure. The area is identified, and the skin is cleansed with an antiseptic solution to reduce the risk of infection.
Depending on the site and the technique chosen, a local anesthetic may be used. In some cases, ultrasound is used to assist in identifying the structure and guiding the placement of the needle.
PRP Injection
The prepared PRP is drawn into a syringe and injected into the targeted area. Depending on the diagnosis, the application may be performed within a joint or in an area associated with a tendon.
During the procedure, the patient may feel a sharp prick, pressure, or discomfort. The intensity varies based on the area being treated and the individual's personal sensitivity.
Post-injection guidelines
Following the procedure, the patient receives guidance regarding local care, physical activity, and the resumption of daily routines. These recommendations depend on the specific structure treated and the rehabilitation plan.
It is possible to experience pain or temporary swelling in the area. The physician will also provide instructions on what measures to take or medications to use, should the need arise.
Severe or worsening pain, increasing redness, fever, or any other concerning symptoms should be promptly reported to the physician.
How many injections are required?
There is no single number of injections that is suitable for all patients. The decision depends on the condition treated, the response observed and the protocol chosen.
PRP can be part of a broader treatment plan that includes physical therapy, muscle strengthening, and activity adjustments. The evolution must be monitored by the doctor, respecting the characteristics of each case.
How does PRP work?
Platelet-rich plasma (PRP) acts through a combination of biologically active substances present in both the plasma and the platelets. When activated, platelets release proteins known as growth factors—including PDGF, TGF-β, and VEGF—as well as other molecules that serve as signals to cells.
In laboratory studies and experimental models, these signals have shown the potential to influence the inflammatory response and stimulate the migration and activity of cells involved in tissue repair. Some of these substances also participate in the formation of blood vessels, a process linked to healing. In the context of osteoarthritis, research is further exploring how PRP may influence the joint environment and processes related to inflammation and cartilage degradation.
These mechanisms help explain the interest in this treatment; however, effects observed in a laboratory setting do not guarantee tissue regeneration or consistent outcomes across all patients. Clinical response may also vary depending on the specific condition being treated and the composition of the PRP, which is determined by the method used for its preparation.
What are the indications for PRP in orthopedics?
Platelet-rich plasma (PRP) can be used as a complementary resource in the treatment of certain musculoskeletal conditions. Its use depends on an individualized medical assessment, which takes into account the diagnosis, symptoms, previous treatments, available alternatives, and the scientific evidence for each specific case.
In Brazil, Federal Council of Medicine (CFM) Resolution No. 2,464/2026, in effect since July 15, 2026, regulates the medical use of PRP as an adjuvant—or complementary—treatment for four specific conditions: knee osteoarthritis, lumbar discopathy, lateral epicondylitis of the elbow, and meniscal repair. This regulation replaces the previous one, which had classified its use in musculoskeletal care as experimental.
Knee osteoarthritis
Osteoarthritis—also referred to as arthrosis—can cause pain, stiffness, and difficulty in walking or performing daily activities. For such patients, PRP (platelet-rich plasma) may be considered as part of a treatment plan to help manage symptoms and improve function.
Among the clinical indications evaluated by the Federal Council of Medicine (CFM), knee osteoarthritis is supported by the most consistent body of evidence. Even so, study results are not uniform, and patient responses vary. PRP is not a substitute for other measures—such as rehabilitation, muscle strengthening, or other interventions—that may be indicated for an individual case.
Meniscal repair
The menisci are structures that contribute to load distribution and the protection of the knee joint. In certain types of injuries, surgery to repair the meniscus may be indicated.
In such cases, PRP (platelet-rich plasma) may be considered as a complementary resource to the repair. Its use does not replace the appropriate surgical technique, nor does it guarantee the healing of the meniscus. Rehabilitation and postoperative follow-up remain essential components of the treatment.
Lateral epicondylitis of the elbow
Known as “tennis elbow,” lateral epicondylitis causes pain on the outer side of the elbow, often linked to the use of forearm muscles and tendons, as well as wrist movement.
PRP (platelet-rich plasma) may be considered as a complementary treatment in select cases, following a confirmed diagnosis and an assessment of interventions already undertaken. The resolution acknowledges this application, while noting that the available evidence is more heterogeneous than that for knee osteoarthritis.
Lumbar discopathy
Lumbar disc disease involves changes in the discs located between the vertebrae in the lumbar region. The presence of changes in an imaging exam, in itself, does not mean that PRP is indicated: it is necessary to relate the findings to the symptoms and clinical evaluation.
As this is a region of greater complexity, the resolution establishes that PRP procedures involving the spine are carried out with image guidance, in a hospital or day hospital environment, by a doctor with qualifications provided for in the standard.
Can PRP be used for other injuries?
PRP is also the subject of research for other conditions, including various tendinopathies and musculoskeletal injuries. However, these other situations are not among the four clinical indications provided for in CFM Resolution No. 2,464/2026.
When should PRP not be used?
The resolution prohibits the use of PRP in several situations, including when there is an active infection at the application site, active neoplasia (cancer), a clinically significant reduction in platelet count, or uncorrected blood disorders or coagulation issues that are incompatible with the procedure. Therefore, it is essential to inform your physician about your medical history and all medications you are currently taking.
Even in cases where its use is regulated, PRP is not automatically indicated. Patients must be provided with information regarding potential benefits, risks, scientific limitations, and alternative treatment options, enabling them to make an informed decision. PRP should not be presented as a guaranteed cure, a promise of tissue regeneration, or a substitute for a formally indicated surgical procedure.
Are there risks?
Because PRP is prepared using the patient’s own blood, the risk of an immune reaction to the product is reduced. Nevertheless, the application is an invasive procedure and may lead to pain, swelling, bleeding, bruising (hematoma), or infection, in addition to risks specific to the area being treated.
Before deciding to undergo the procedure, it is important to discuss any pre-existing medical conditions, current medications, and other factors that could affect the safety or outcome of the treatment with your physician.
Can PRP replace physical therapy or surgery?
Not necessarily. Treating an orthopedic condition may involve activity guidance, muscle strengthening, rehabilitation, medication, and other measures, depending on the specific case.
When considered, PRP may be incorporated into a broader treatment plan as a complementary therapy. Likewise, it does not eliminate the need for surgery in every situation.
How can I determine if PRP is an option for me?
The first step is to obtain a diagnosis and understand the underlying cause of your symptoms. The decision should take into account the specific condition being treated, the severity of your symptoms, previous treatments you have undergone, available scientific evidence, and your personal expectations.
While PRP is an area of growing interest within orthopedics, its results are not guaranteed. A one-on-one conversation with an orthopedist helps in evaluating potential benefits and limitations, as well as in determining the most appropriate course of action for each individual case.
What do scientific studies say about PRP in orthopedics?
Platelet-rich plasma (PRP) has been studied for the treatment of various orthopedic conditions, most notably knee osteoarthritis and certain tendon disorders. While results are promising in specific scenarios, there remains some variation across studies. To properly interpret this evidence, it is important to consider the specific condition being treated, the alternative treatment to which PRP was compared, and the duration of patient follow-up.
PRP and hyaluronic acid for knee osteoarthritis
Hyaluronic acid is used in intra-articular injections to help manage the symptoms of osteoarthritis. Several studies have compared this option to PRP, focusing primarily on pain levels and knee function.
A systematic review published in 2024 synthesized findings from clinical trials and observed that PRP yielded a higher rate of satisfactory outcomes compared to hyaluronic acid. The analysis also indicated improvements in certain symptom-related outcomes when PRP was compared to other non-surgical treatment alternatives.
These findings suggest that PRP may be a viable option for some patients, though it is not necessarily superior to hyaluronic acid in every case. Studies vary in terms of the type of PRP used, the number of injections administered, and the criteria for evaluation. Furthermore, some individual studies lack statistically robust results, which underscores the need to interpret the data with caution.
PRP and corticosteroids
Corticosteroids are anti-inflammatory medications that can be administered via injection to alleviate the symptoms of osteoarthritis. Their use depends on the patient's specific characteristics and the stage of their treatment. A systematic review comparing various injectable treatments observed that, in assessments conducted from six months onwards, patients treated with PRP showed, on average, better outcomes regarding pain and function than those who received corticosteroids. Hyaluronic acid also demonstrated superior results compared to corticosteroids in this analysis.
However, such comparisons depend on the timeframe evaluated and the specific characteristics of the studies. Therefore, an average result favoring PRP at a given point in time does not necessarily mean it is the best choice for every patient or for every stage of treatment.
PRP compared to a placebo
While comparing PRP with other types of injections is important, comparing it against a placebo—such as an injection of saline solution—also helps to determine how much of the observed improvement can be attributed to the preparation itself.
In the RESTORE study, published in the journal JAMA in 2021, 288 people with mild to moderate knee osteoarthritis were assigned to receive either PRP or a placebo. After 12 months, both groups showed an average improvement in pain, but the difference between them was not statistically significant. The study also found no significant difference in changes to cartilage volume, as assessed by magnetic resonance imaging (MRI).
This result illustrates why any improvement observed following an injection must be interpreted with caution. It also reinforces that cartilage regeneration or the halting of osteoarthritis progression has not been proven as a guaranteed outcome of PRP treatment.
What about tendon injuries?
PRP is also being investigated for use in tendinopathies, including patellar tendinopathy, which can cause pain in the front of the knee and limit participation in sports activities.
In a clinical study involving 57 participants, researchers compared two types of PRP—one with a higher concentration of leukocytes and one with a lower concentration—against an injection of saline solution. All participants also followed a rehabilitation program. In this study, PRP showed no clear advantage over the saline solution regarding the outcomes measured.
While this does not settle the debate, it demonstrates that results vary depending on the specific condition being treated, and that it is inappropriate to extrapolate findings from knee osteoarthritis to all types of tendon injuries.
Why do study results differ?
The term "PRP" encompasses various preparations that may differ in their platelet concentration and the presence of other cells, such as leukocytes. Furthermore, studies may include patients with varying degrees of osteoarthritis, involve one or multiple injections, and track outcomes over different timeframes.
These variations make direct comparisons between studies difficult and help explain why questions remain regarding which formulation to use, how many injections should be administered, and which patients are most likely to benefit.
How should this information be interpreted?
Research indicates that PRP may contribute to improvements in pain and function for some patients with knee osteoarthritis, with some studies showing favorable results compared to other types of injections. Conversely, placebo-controlled studies have yielded less favorable outcomes, and the response in cases of tendinopathy remains variable.
Therefore, the choice should be individualized, taking into account the diagnosis, the severity of symptoms, previous treatments, available alternatives, and the patient's expectations. PRP can be part of a broader treatment plan that includes rehabilitation and muscle strengthening.
Scientific references
Oeding JF, et al. Platelet-Rich Plasma Versus Alternative Injections for Osteoarthritis of the Knee: A Systematic Review and Statistical Fragility Index–Based Meta-analysis of Randomized Controlled Trials. The American Journal of Sports Medicine. 2024.
Jawanda S, et al. Platelet-Rich Plasma, Bone Marrow Aspirate Concentrate, and Hyaluronic Acid Injections Outperform Corticosteroids in Pain and Function Scores at a Minimum of 6 Months as Intra-Articular Injections for Knee Osteoarthritis. Arthroscopy. 2024.
Bennell KL, et al. Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial. JAMA. 2021.
Scott A, et al. Platelet-Rich Plasma for Patellar Tendinopathy: A Randomized Controlled Trial of Leukocyte-Rich PRP or Leukocyte-Poor PRP Versus Saline. The American Journal of Sports Medicine. 2019.
About the author
Dr. Daniel Hidalgo is an orthopedist and traumatologist specializing in knee surgery and arthroscopy. A graduate of the ABC Medical School (Faculdade de Medicina do ABC), he completed his residency in Orthopedics and Traumatology, as well as a specialization in Knee Surgery, at Santa Casa de São Paulo. He holds an Executive MBA in Healthcare Management from the Albert Einstein Israelite Hospital and completed an observership at the Croix-Rousse Hospital in Lyon, France.
He is a member of the Brazilian Society of Orthopedics and Traumatology (SBOT), the Brazilian Society of Knee Surgery (SBCJ), and the Brazilian Medical Society for Shockwave Treatment (SMBTOC). On his blog, he shares information regarding knee health, injury prevention, and orthopedic treatments, using accessible language backed by scientific evidence.
Editorial note: This content was developed with the aid of artificial intelligence and reviewed and adjusted by Dr. Daniel Hidalgo, who is responsible for the final version of the text.
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