From the Guidelines
Platelet-rich plasma (PRP) knee injections may reduce pain and improve function in patients with symptomatic osteoarthritis of the knee, although the evidence is limited and the strength of recommendation is downgraded. The purpose of a PRP knee injection is to deliver growth factors and proteins that may reduce inflammation and promote tissue healing, potentially providing moderate relief for knee osteoarthritis pain 1. The procedure involves drawing the patient's blood, processing it to concentrate platelets, and injecting this platelet-rich solution into the knee joint.
Key Points to Consider
- Typically, patients receive 1-3 injections spaced 2-4 weeks apart, with possible maintenance injections every 6-12 months if beneficial 1.
- The procedure takes about 30 minutes in an outpatient setting, with minimal recovery time.
- Side effects are generally mild and include temporary pain, swelling, or stiffness at the injection site.
- Insurance rarely covers these injections, with costs ranging from $500-$2,000 per injection.
- While some patients experience significant pain relief lasting 6-12 months, results vary considerably between individuals, and it is essential to discuss with a doctor whether this treatment is appropriate for a specific knee condition compared to other options like physical therapy, corticosteroid injections, or surgery 1.
Evidence and Recommendations
The American Academy of Orthopaedic Surgeons suggests that practitioners should feel little constraint in following a recommendation labeled Limited, exercise clinical judgment, and be alert for emerging evidence that clarifies or helps to determine the balance between benefits and potential harm 1. Patient preference should have a substantial influencing role in the decision-making process. Although there is some evidence supporting the use of PRP injections, the lack of reproducibility and variability in treatment response limit the strength of the recommendation 1.
From the Research
Purpose of Platelet-Rich Plasma (PRP) Knee Injections
The purpose of PRP knee injections is to reduce pain and improve function in patients with knee osteoarthritis (KO) or other knee-related conditions.
- PRP injections are used to treat knee pain associated with articular cartilage and degenerative meniscal lesions 2
- They are also used to reduce pain and stiffness, and enhance physical function in patients with knee osteoarthritis 3
- The injections can be used in combination with other treatments, such as hyaluronic acid, to provide a synergistic effect and improve outcomes 4, 5
Mechanism of Action
The mechanism of action of PRP injections involves the use of growth factors to promote regeneration, repair, and acceleration of the biochemical process, thereby reducing pain and improving function.
- The growth factors in PRP play a role in the regeneration and repair of damaged tissues, including articular cartilage and meniscus 2
- The use of PRP injections can lead to significant improvements in pain and function, particularly when used in combination with other treatments 4, 3, 5
Efficacy of PRP Injections
The efficacy of PRP injections in treating knee osteoarthritis and other knee-related conditions has been studied in several clinical trials.
- Some studies have shown that PRP injections can provide significant improvements in pain and function, particularly when used in combination with other treatments 4, 3, 5
- However, other studies have found that PRP injections may not be effective in reducing pain and improving function in all patients, and that further research is needed to fully understand their efficacy 6