From the Guidelines
Platelet-rich plasma (PRP) injections for knee pain are not recommended as a first-line treatment due to inconsistent evidence and variable results, as stated in the 2022 AAOS clinical practice guideline summary 1. The evidence for PRP injections in knee pain management is mixed, with some studies showing moderate pain relief and functional improvement, while others report no significant benefits 1. The procedure involves drawing the patient's blood, processing it to concentrate platelets, and injecting this concentration into the knee joint. Typically, patients receive 1-3 injections spaced 1-4 weeks apart, with possible maintenance injections every 6-12 months. PRP works by delivering growth factors and bioactive proteins that may reduce inflammation and promote tissue healing. However, results vary significantly between patients, and insurance rarely covers the treatment (costs range from $500-$2,000 per injection). Some key points to consider when evaluating PRP injections for knee pain include:
- The quality of the evidence is generally low to moderate, with few high-quality studies supporting its use 1.
- The duration of benefits is often short-lived, lasting only a few months 1.
- PRP appears most effective for early to moderate osteoarthritis rather than advanced joint damage 1.
- Patients should maintain realistic expectations as it's not a cure for underlying joint degeneration.
- Side effects are generally minimal but may include temporary pain, swelling, or stiffness at the injection site. Given the inconsistent evidence and variable results, patients should discuss this option with their healthcare provider to determine if it's appropriate for their specific condition, considering other established treatments such as exercise, weight loss, and oral nonsteroidal anti-inflammatory drugs (NSAIDs) 1.
From the Research
PRP Injection for Knee Pain Evidence
- The use of platelet-rich plasma (PRP) injections for treating knee osteoarthritis has been studied in several research papers 2, 3, 4, 5.
- A 2018 review suggests that PRP is a safe and effective nonoperative treatment method for knee osteoarthritis, with positive effects at all stages of the condition 2.
- A 2014 review found that PRP is similar in efficacy to hyaluronic acid and may be more effective in younger, active patients with low-grade osteoarthritis 3.
- A 2020 systematic review and meta-analysis found that PRP is superior to hyaluronic acid for symptomatic knee pain at 6 and 12 months, but there were no advantages of PRP over hyaluronic acid for clinical outcomes at both 6 and 12 months 4.
- A 2021 systematic review and meta-analysis found that patients undergoing treatment for knee osteoarthritis with PRP can be expected to experience improved clinical outcomes when compared with hyaluronic acid, and leukocyte-poor PRP may be a superior line of treatment for knee OA over leukocyte-rich PRP 5.
Comparison with Other Treatments
- A 2023 review found that first-line management of osteoarthritis comprises exercise therapy, weight loss, education, and self-management programs, and surgical referral for knee joint replacement can be considered for patients with end-stage OA 6.
- The same review found that conservative management, such as exercise therapy, is also appropriate for most meniscal tears and patellofemoral pain 6.
Efficacy and Safety
- The studies suggest that PRP injections are a safe and effective treatment option for knee osteoarthritis, with significant improvements in pain and clinical outcomes compared to hyaluronic acid 2, 3, 4, 5.
- However, the optimal PRP protocol remains unclear, and future investigations should control and analyze the effects of various treatment variables in PRP treatment 3.