Platelet-Rich Plasma (PRP) Injections for Knee Osteoarthritis
Do not use platelet-rich plasma injections for knee osteoarthritis—the American College of Rheumatology/Arthritis Foundation strongly recommends against this treatment due to lack of standardization, heterogeneity in preparations, and insufficient evidence of benefit. 1
Guideline-Based Recommendation
The 2019 ACR/AF guidelines provide a strong recommendation against PRP for knee and hip osteoarthritis, which represents the highest level of negative recommendation possible. 1 This strong stance is based on:
Critical concerns about heterogeneity: There is no standardization in PRP preparations, with significant variability in platelet concentration, leukocyte content, activation methods, and injection protocols, making it impossible to identify what is actually being injected. 1, 2
Lack of reproducible evidence: The American Academy of Orthopaedic Surgeons notes that while some studies show benefit, the evidence demonstrates inconsistency, with worse treatment responses in patients with severe knee osteoarthritis. 2
Medicare non-coverage: Given the strong recommendations against PRP from major organizations, Medicare does not cover this treatment for knee pain. 2
Why This Differs from Other Injections
Unlike hyaluronic acid (which has a conditional recommendation against for knee OA), PRP receives a strong recommendation against. 1 This distinction is important:
- Hyaluronic acid has standardized preparations and can be considered after exhausting other options through shared decision-making. 1
- PRP lacks this standardization entirely, making it fundamentally different from other injectables. 1
Evidence Limitations
While some older research suggested potential benefits (particularly a 2016 systematic review showing improvements over hyaluronic acid at 3-12 months 3), more recent high-quality evidence contradicts this:
- A 2022 randomized controlled trial (the PEAK trial) found no additional beneficial effect of single or multiple PRP injections compared to saline injections at 12 months follow-up. 4
- The improvements seen in all groups (including saline) suggest a strong placebo effect. 4
Recommended Evidence-Based Alternatives
Instead of PRP, use this treatment algorithm for knee osteoarthritis:
First-Line Treatments (Medicare-covered):
- Structured exercise programs and physical therapy (strongly recommended). 2
- Weight management for overweight patients. 2
- Oral or topical NSAIDs where appropriate. 2
Second-Line Treatment:
- Intra-articular corticosteroid injections for patients with inadequate response to first-line treatments, providing approximately 3 months of benefit. 2
Third-Line Consideration:
- Hyaluronic acid injections may be considered only after failure of the above treatments, through shared decision-making that acknowledges limited evidence of benefit. 1
Clinical Pitfall to Avoid
Do not be swayed by patient requests for PRP based on marketing or anecdotal reports. 2 The lack of standardization means that even if one preparation showed benefit in research, there is no way to ensure the commercial product being used is equivalent. 1 This fundamental problem distinguishes PRP from other treatments and justifies the strong recommendation against its use.