10/05/2025
This is human data. We don’t have quite the same
Level of data for dogs yet but we are getting there.
🩸 Platelet-Rich Plasma (PRP) for Knee Osteoarthritis (KOA): Current Evidence and Clinical Implications (June, 2025)
👉Platelet-rich plasma (PRP) is an increasingly utilized, promising, and safe therapeutic option for managing Knee Osteoarthritis (KOA)
■ This comprehensive review summarizes the clinical efficacy, mechanism of action, and implementation challenges of PRP therapy, drawing upon 40 high-quality studies published between 2013 and March 2025
📝 ■As physiotherapists, we frequently guide patients through the non-operative management of Knee Osteoarthritis (KOA), often encountering those who have recently undergone intra-articular injections, including Platelet-Rich Plasma (PRP) ■ Understanding the biological mechanisms, clinical efficacy, and crucial post-injection restrictions of PRP is essential for optimizing rehabilitation protocols and managing patient expectations
📈 Key Findings on Clinical Efficacy and Comparisons
■ Overall Efficacy: PRP injections are a promising, safe, and well-tolerated option for patients with early to moderate KOA (Kellgren–Lawrence grades I–III)
■ Pain Relief and Function: PRP provides pain relief and functional improvement that often persists for 6 to 12 months ■ Functional gains are consistently observed in early to moderate KOA (KL I–II)
💧 PRP vs. Hyaluronic Acid (HA)
■ PRP demonstrates superior pain relief and functional improvement compared to HA
■ Meta-analyses show that PRP is superior to HA for pain and function at 12 months ■ For instance, PRP produced significantly greater improvements in WOMAC total and pain scores versus HA at 12 months in some studies
■ In comparison summaries, PRP consistently outperformed HA at 3, 6, and 12 months, with differences often being statistically significant ($p < 0.01$)
■ Combination therapy using PRP + HA has also been indicated as ranking highest for pain reduction in network meta-analyses
💉 PRP vs. Corticosteroids
■ PRP provides longer symptom relief than corticosteroid injections ■ Corticosteroids typically lose effectiveness after 4–6 weeks ■ PRP outperformed corticosteroids in pain and functional outcomes at 3 and 6 months post-injection
💊 Placebo Considerations
■ Evidence from high-quality placebo-controlled trials (such as the RESTORE trial) shows inconsistent long-term benefits, with some studies failing to demonstrate superiority over saline beyond 6–12 months ■ This highlights that PRP's therapeutic benefit may involve a transient biological effect and/or a significant placebo effect
🦴 Structural Effects
■ Current evidence is insufficient to conclude that PRP has a disease-modifying or structural effect, such as delaying radiographic progression or preventing cartilage loss
⚙️ Mechanism of Action
■ Autologous Source: PRP is an autologous product derived from centrifuged whole blood
■ Bioactive Molecules: PRP contains a concentrated mixture of platelets and bioactive growth factors, including transforming growth factor-beta (TGF-β), platelet-derived growth factor (PDGF), insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF)
■ Function: When injected, these factors modulate inflammation, promote tissue repair, stimulate anabolic processes in chondrocytes and synoviocytes, and help restore the balance between pro-inflammatory and anti-inflammatory factors in the joint ■ PRP treatment has been shown to counteract the effects of inflammatory cytokines like interleukin-1β (IL-1β) on chondrocytes
🛡️ Safety Profile and Adverse Events (AEs)
■ High Tolerability: PRP is considered safe and well-tolerated due to its autologous nature, which minimizes immunologic reactions
■ Common AEs: Adverse events are predominantly mild, transient, and localized, including post-injection pain flare-ups, swelling, or stiffness, typically resolving within 24–48 hours
■ Serious AEs: Serious adverse events, such as joint infection or accelerated cartilage degeneration, are rare and have not been reported in large trials
■ Formulation Safety: Leukocyte-poor PRP (LP-PRP) is often preferred for intra-articular use, as it is associated with significantly fewer adverse events compared to leukocyte-rich PRP (LR-PRP)
👥 Practical Implementation and Patient Selection
■ Ideal Candidates: PRP yields the most favorable outcomes in patients with:
□ Mild-to-moderate KOA (KL grades II–III)
□ Younger age (typically 35 kg/m²) are less likely to benefit
■ Injection Protocols: While optimal regimens vary, many RCTs use a repeated injection protocol, often a three-weekly injection series, which tends to offer more lasting benefits than single injections
■ Post-Injection Care: Patients are typically advised to rest for one or two days and avoid nonsteroidal anti-inflammatory drugs (NSAIDs) for 1–2 weeks post-injection to allow the PRP-induced inflammatory cascade to proceed without interference
📚 Guideline Status and Future Standardization Needs
■ Caution from Major Societies: Major clinical guidelines from organizations such as the American College of Rheumatology (ACR/AF) and the American Academy of Orthopaedic Surgeons (AAOS) remain cautious or inconclusive regarding the routine use of PRP, citing study heterogeneity and lack of standardization
■ Emerging Support: European expert consensus groups (e.g., ESSKA ORBIT 2024, GRIP 2020) have adopted more favorable positions, supporting PRP for early to moderate KOA as a second-line therapy after conventional treatments fail, often recommending LP-PRP
■ Need for Standardization: Significant variability exists in PRP preparation protocols (e.g., platelet/leukocyte content and activation methods), injection regimens, and outcome measures, limiting comparability across studies ■ Standardization is essential for clinical practice, potentially requiring the adoption of classification systems like PAW or DEPA
■ Cost and Access: PRP treatment often remains costly and is variably reimbursed, frequently requiring patients to pay out-of-pocket
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⚠️Disclaimer: Sharing a study or a part of it is NOT an endorsement. Please read the original article and evaluate critically.⚠️
Link to Article 👇
