Knee Osteoarthritis Research Update: Platelet-Rich Plasma (PRP) versus Hyaluronic Acid (Gel)

Image Courtesy of Physiopedia

Knee osteoarthritis is one of the most common diagnoses encountered in orthopaedic practice.  Multiple treatment options are available including physical therapy, bracing, corticosteroid injections, hyaluronic acid (gel) injections, platelet-rich plasma (PRP) injections, and surgery (total knee replacement). 

There is literature showing corticosteroid injection may have a negative effect on the cartilage (cushioning) of the knee, confirmed by 2-year follow-up MRI evaluation after injection (Bharadwaj et al., Radiology, 2025). 

Given the potential negative effects of corticosteroid injection on the long-term health of the knee, interest in gel injections and PRP has grown, particularly for patients who desire a non-surgical treatment plan or are not surgical candidates.

Which is a Better Option: PRP or Gel?

This is a common question encountered in my daily clinical practice.  A recent publication in Arthroscopy: The Journal of Arthroscopic and Related Surgery provides an up-to-date evidence-based answer (Li et al, Arthroscopy, 2025).

Key Study Design Aspects

Li et al. performed a meta-analysis of 15 randomized double-blind controlled trials comparing patient outcomes after PRP and gel injections.  

Total number of patients analyzed: 1,632

• 837 received PRP injection

• 795 received gel injection

• Severity of osteoarthritis included in study: Grade 1-3 (mild to moderate)

Outcomes measured

• Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, which evaluates pain, stiffness, and physical function

• International Knee Documentation Committee (IKDC) scores, which evaluates knee function and symptoms

• Visual Analog Scale (VAS) scores, which evaluate pain

• Cartilage (cushioning) thickness as determined by MRI

Key Results

 WOMAC Pain Score

• 3 and 6 months post-injection: No significant difference between groups

• 12 months post-injection: PRP injection group showed statistically and clinically significant greater improvement than the gel injection group

WOMAC Function Score

• 3, 6, and 12 months post-injection: PRP injection group showed greater improvement than the gel injection group, but not statistically significant

 WOMAC Stiffness Score

• 6 and 12 months post-injection: PRP injection group showed greater improvement than the gel injection group, but not statistically significant

 WOMAC Total Score

• 3 and 6 months post-injection: No significant difference between groups

• 12 months post-injection: PRP injection group showed statistically and clinically significant greater improvement than the gel injection group  

VAS Score

• 1 and 6 months post-injection: No significant difference between groups

• 12 months post-injection: PRP injection group showed statistically significant greater improvement than the gel injection group

IKDC Score

• 1 month post-injection: PRP injection group showed statistically and clinically significant greater improvement than the gel injection group

• 6 and 12 months post-injection: No significant difference between groups

MRI Findings

• One study showed at least one grade improvement on MRI 6 months post-injection in 48.3% of patients after PRP injection and 8% of patients after gel injection (Lisi et al; Clin Rehabil, 2018).

• Another study showed no difference in cartilage appearance on MRI at 12-month follow-up (Tschopp et al., Invest Radiol, 2024)

Key Takeaways

• Short term (3-6 months): Both PRP and gel injections are reasonable non-surgical treatment options for mild to moderate knee osteoarthritis with no significant outcome differences

• Long-term (12 months): PRP provides statistically and clinically significant better pain and function outcomes compared to gel injection.

Appointment

Dr. Verma provides treatment for orthopaedic and sports medicine conditions of the shoulder, elbow, hand/wrist, hip, knee, and foot/ankle. If you are interested in exploring treatment for your condition, please schedule a consultation with Dr. Verma to discuss the available options. 

References

1. Bharadwaj UU, Lynch JA, Joseph GB, et al. Intra-articular Knee Injections and Progression of Knee Osteoarthritis: Data from the Osteoarthritis Initiative. Radiology. 2025;315(2):e233081. doi:10.1148/radiol.233081

2. Li YF, Xing HH, Wei CK, et al. Platelet-Rich Plasma Is More Effective Than Hyaluronic Acid Injections for Osteoarthritis of the Knee: A Meta-Analysis Based on Randomized, Double-blinded, Controlled Clinical Trials. Arthroscopy. Published online July 16, 2025. doi:10.1016/j.arthro.2025.06.033

3. Lisi C, Perotti C, Scudeller L, et al. Treatment of knee osteoarthritis: platelet-derived growth factors vs. hyaluronic acid. A randomized controlled trial. Clin Rehabil. 2018;32(3):330-339. doi:10.1177/0269215517724193

4. Tschopp M, Pfirrmann CWA, Brunner F, et al. Morphological and Quantitative Parametric MRI Follow-up of Cartilage Changes Before and After Intra-articular Injection Therapy in Patients With Mild to Moderate Knee Osteoarthritis: A Randomized, Placebo-Controlled Trial. Invest Radiol. 2024;59(9):646-655. 

5. Physiopedia. Knee Osteoarthritis. Physiopedia. Published 2014. https://www.physio-pedia.com/Knee_Osteoarthritis