From the Guidelines
Platelet-rich plasma (PRP) injections may be considered for knee osteoarthritis, as they have shown moderate efficacy in providing pain relief and improved function for many patients, although the evidence is not consistent and the benefits may vary between individuals. The use of PRP for knee osteoarthritis is supported by some studies, including a 2022 guideline summary from the American Academy of Orthopaedic Surgeons, which found that PRP had reduced pain and improved function in patients with knee osteoarthritis, although the evidence demonstrated inconsistency and a worse treatment response in patients with severe knee osteoarthritis 1.
Key Points to Consider
- The typical regimen for PRP injections involves 1-3 injections spaced 2-4 weeks apart, with each procedure taking about 30 minutes.
- The process involves drawing the patient's blood, processing it to concentrate platelets, and injecting this concentration into the knee joint.
- PRP works by delivering growth factors and bioactive proteins that reduce inflammation and potentially stimulate healing and tissue regeneration.
- Patients generally experience best results when PRP is used for mild to moderate arthritis rather than severe joint degeneration.
- Side effects are minimal, typically limited to temporary pain at the injection site.
Evidence and Recommendations
The evidence for PRP injections in knee osteoarthritis is not consistent, and the benefits may vary between individuals. A 2021 study found that the results of the studies on PRP for knee osteoarthritis were inconsistent, and the clinical importance of the statistically significant difference in pain reduction was unclear 1. However, a 2022 guideline summary from the American Academy of Orthopaedic Surgeons found that PRP had reduced pain and improved function in patients with knee osteoarthritis, although the evidence demonstrated inconsistency and a worse treatment response in patients with severe knee osteoarthritis 1.
Considerations for Treatment
When considering PRP injections for knee osteoarthritis, it is essential to weigh the potential benefits and risks, as well as the individual patient's circumstances and preferences. The cost of PRP injections can vary widely, and insurance coverage may be limited. Additionally, the evidence for PRP injections is not consistent, and the benefits may vary between individuals. Therefore, PRP injections should be considered on a case-by-case basis, taking into account the individual patient's needs and circumstances.
From the Research
Efficacy of PRP Injections for Knee Arthritis
- The efficacy of PRP injections for knee arthritis has been studied in several randomized controlled trials and systematic reviews 2, 3, 4, 5, 6.
- A systematic review and meta-analysis of randomized controlled trials found that PRP injections resulted in significant improvements in pain and functional outcomes in patients with knee osteoarthritis, with a mean improvement of 44.7% in WOMAC total scores compared to 12.6% for hyaluronic acid injections 4.
- Another study found that PRP injections provided clinically significant pain relief and functional improvement at 1-, 3-, 6-, and 12-month follow-up points compared to placebo, with high-platelet PRP providing superior pain relief and more durable functional improvement compared to low-platelet PRP 5.
- A network meta-analysis of randomized controlled trials found that PRP injections had a high P-Score for WOMAC score at 6-months follow-up, indicating a high probability of being the best treatment option 3.
- Combination therapy with PRP and hyaluronic acid has also been studied, with one systematic review finding that it improves patient-reported outcomes and is superior to hyaluronic acid alone, but not superior to PRP alone 6.
Comparison to Other Treatments
- PRP injections have been compared to other treatments for knee osteoarthritis, including hyaluronic acid, corticosteroids, and mesenchymal stem cells 3, 4.
- A systematic review and meta-analysis found that PRP injections were superior to hyaluronic acid injections in terms of pain relief and functional improvement 4.
- Another study found that PRP injections were not superior to stromal vascular fraction injections, which had the highest P-Score for VAS score and WOMAC score at all post-injection time points 3.
Factors Influencing Efficacy
- Platelet concentration has been found to influence the efficacy of PRP injections, with high-platelet PRP providing superior pain relief and more durable functional improvement compared to low-platelet PRP 5.
- Leukocyte content has also been found to influence the efficacy of PRP injections, with leukocyte-poor PRP associated with significantly better subjective IKDC scores compared to leukocyte-rich PRP 4.