UPDATE ON THE USE OF PLATELET-RICH PLASMA (PRP) IN THE TREATMENT OF KNEE OSTEOARTHRITIS

UPDATE ON THE USE OF PLATELET-RICH PLASMA (PRP) IN THE TREATMENT OF KNEE OSTEOARTHRITIS

DR JORDI JIMENEZ

In early 2024, the European Society for Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) published the results of a consensus meeting of clinical experts and specialists in knee pathology. The objective of this meeting was to provide evidence-based recommendations to improve decision-making and indications for platelet-rich plasma (PRP) treatment in knee osteoarthritis.

This article summarizes the most important aspects of these consensus and recommendations in the following points:

A.- Regarding the indication of PRP in knee osteoarthritis :

1.-Today, there is considered sufficient clinical evidence to support the use of PRP in the treatment of mild to moderate knee osteoarthritis . In cases of severe knee osteoarthritis, its use is considered in patients who do not wish to undergo surgery or are not suitable for surgery, although its effectiveness may be reduced.

Regarding knee osteoarthritis with exclusive involvement of the patellofemoral joint (between the patella and femur), there is consensus on the use of PRP as an alternative treatment, especially in the early stages .

2.- Regarding the contraindications of PRP treatment, although most of them have not been sufficiently studied, the group of experts lists the following:

Infection or problems in the skin area to be punctured .

• Active general infections
• Active malignant neoplasms , extending the recommendation to neoplasms with or without metastasis, outside or even at a distance from the knee.
• Thrombocytopenia (low platelet count) or thrombocytosis (high platelet count).
• Coagulopathies (blood clotting disorders).
• The use of antiplatelet medication is considered a relative contraindication, especially in patients who cannot receive surgical treatment. The expected reduced effect after administration should be noted.
• Rheumatoid arthritis, Crohn's disease and other inflammatory or autoimmune diseases DO NOT prevent the administration of PRP , although in these patients the presence of high levels of proinflammatory mediators in the plasma may reduce its effect.

3. The question of the optimal age range for administering PRP treatment was also raised. Most studies report a mean age of 55 to 65 years. The recommendation is to consider other factors, not just the patient's chronological age . Advanced age is clearly associated with a reduced response to PRP treatment.

4. In cases of knee osteoarthritis in the inflammatory phase with joint effusion, studies suggest that the anti-inflammatory effect of PRP supports its use . There is consensus that arthrocentesis (aspiration of joint effusion) should be performed beforehand.

5.-In those patients in whom the symptoms of knee osteoarthritis reappear after a successful cycle of PRP treatment, experts consider a new cycle of treatment acceptable if the symptoms reappear .

6. There are insufficient studies addressing the preventive use of PRP in the treatment of early asymptomatic knee osteoarthritis. Although preclinical studies suggest a chondroprotective effect of PRP in the knee, experts agree that there is insufficient evidence to justify the preventive use of PRP in knees with early asymptomatic osteoarthritis .

7.- Several studies demonstrate the short-term symptomatic benefit of corticosteroid treatment for knee osteoarthritis. This benefit is not without side effects, including chondrotoxicity (cartilage degeneration), especially with multiple treatment cycles.

Comparative studies with PRP treatment show that the latter has an advantage over corticosteroid treatment in terms of long-term improvement of knee osteoarthritis symptoms . Experts agree that PRP treatment is more effective and avoids the side effects of corticosteroids, making it a safer treatment alternative.

8.-There are multiple studies comparing the effectiveness of PRP with hyaluronic acid for the treatment of knee osteoarthritis, and most favor PRP in terms of efficacy and durability of clinical improvement. This is why there is consensus in supporting the use of PRP over hyaluronic acid .

9.- Although at a preclinical level, treatment with PRP shows some modifying effects on knee osteoarthritis, at the level of the cartilage and synovial membrane, the group of experts recognizes that the existing scientific evidence is insufficient to consider that the use of PRP in knee osteoarthritis exerts any modifying effect on the evolution of the disease .

 

B.- Regarding the preparation and types of PRP :

1.-Regarding the presence or absence of leukocytes in the preparation (leukocyte-rich PRP (LR-PRP) or leukocyte-poor PRP (LP-PRP)), the group of experts does not support the use of one type over the other and considers both preparations valid for the treatment of knee osteoarthritis.

2.- Regarding the number of platelets or platelet concentrate in the preparation, the consensus group considers that a clear correlation has not been established between the number of platelets present in the preparation and its clinical effect, and therefore establishes that the optimal platelet ranges in the treatment of knee osteoarthritis cannot currently be defined .

3. Regarding the volume of the PRP preparation, experts agree that there is no evidence in the literature regarding the optimal volume of preparation to be injected , which can vary from 2 to 12 ml. They do consider the size of the knee to be treated.

 

C.- Regarding the PRP treatment protocol :

 

1.-Regarding the number of PRP injections per cycle in the treatment of knee osteoarthritis, the consensus group recommends between 2 and 4 injections per cycle .

2.-Regarding the recommended time interval between PRP infiltrations, although the literature does not conclude an optimal time period, the consensus group believes a time period of 1 to 3 weeks is acceptable .

3.- It is recommended to avoid the use of NSAIDs (nonsteroidal anti-inflammatory drugs) two weeks before PRP injection and one week after its administration. If analgesics are required, paracetamol, dipyrone, or tramadol, which do not have an anti-inflammatory effect, can be used.

4. There are no high-quality studies examining the use of local anesthetics prior to PRP injection in the treatment of knee osteoarthritis. In vitro studies associate the use of local anesthetics with decreased platelet function and, consequently, a reduced effect of the injected PRP. The consensus group does not recommend the use of intra-articular local anesthetics when injecting PRP, but they do support its subcutaneous administration prior to the procedure .

5.-The group of experts does not recommend the use of antibiotics around the administration of PRP in knee osteoarthritis.

6.-Regarding diet in the days prior to PRP treatment, the consensus group recommends that patients avoid fatty foods at least 24 hours before blood draw and avoid alcohol consumption for 48 hours prior to treatment.

7. -Regarding the use of corticosteroids close to PRP treatment, it is recommended to separate both treatments in time, and if the patient has received previous treatment with corticosteroids, delay PRP infiltration for a minimum of 6 weeks .

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