What is the current evidence for Platelet-Rich Plasma (PRP) therapy in treating degenerative arthritis?

Current Evidence for PRP in Degenerative Arthritis

The American College of Rheumatology/Arthritis Foundation strongly recommends against using PRP for knee and hip osteoarthritis due to concerns about lack of standardization and heterogeneity in preparations 1. However, this recommendation conflicts with emerging research evidence showing clinical benefits, creating a significant gap between guideline recommendations and research findings.

The Evidence Paradox

The guideline position stands in stark contrast to multiple research studies demonstrating efficacy:

• A 2023 systematic review and meta-analysis of 24 RCTs (1,344 patients) found PRP injections significantly improved pain scores in knee, ankle, and temporomandibular joint osteoarthritis, but NOT in hip osteoarthritis 2. This aligns with the ACR/AF recommendation against hip OA treatment specifically.

• PRP improved WOMAC scores across all domains (pain, stiffness, and function) compared to controls 2, suggesting functional benefits beyond just pain relief.

• Leukocyte-poor (LP) PRP demonstrated superior analgesic effects compared to leukocyte-rich (LR) PRP 2, indicating that preparation method critically impacts outcomes—a key concern highlighted in the guidelines 1.

Clinical Efficacy by Joint Location

Knee Osteoarthritis

• PRP shows the strongest evidence for knee OA, with significant improvements in VAS pain scores, KOOS subscales (pain, symptoms, ADL, quality of life), and WOMAC scores 2.
• Single-dose PRP injection was more effective than three doses of hyaluronic acid at 3 and 6 months follow-up, with lower cost 3.
• Clinical improvement duration is limited to approximately 9 months median 4, requiring repeat treatments for sustained benefit.

Hip Osteoarthritis

• PRP showed NO significant efficacy for hip OA pain reduction 2, supporting the guideline recommendation against its use in this joint specifically.

Ankle and TMJ Osteoarthritis

• Both showed significant pain reduction with PRP therapy 2, though these are less commonly treated joints.

Critical Technical Considerations

The International Society on Thrombosis and Haemostasis emphasizes that PRP products vary widely in platelet concentration, leukocyte presence, activation methods, and administration protocols 1. This heterogeneity explains both the guideline concerns and inconsistent clinical results.

Essential reporting requirements for any PRP treatment include 1:

• Baseline platelet number, volume, and concentration
• Purity of final preparation
• Activation procedure used
• Volume of blood collected and final platelet concentration

Patient Selection Factors

Younger patients and those with lower degrees of cartilage degeneration achieve significantly better results 4. This suggests PRP should be considered earlier in the disease course rather than as a salvage therapy.

The evidence does NOT support PRP for patients with advanced radiographic osteoarthritis or those considering joint replacement 4.

Common Pitfalls to Avoid

• Do not use PRP for hip osteoarthritis—the evidence shows no benefit 2.
• Avoid leukocyte-rich preparations—LP-PRP demonstrates superior outcomes 2.
• Do not expect durable long-term results—median benefit duration is only 9 months 4, requiring repeat injections.
• Avoid using PRP in advanced disease—efficacy decreases with increasing cartilage degeneration 4.
• Do not use standardized protocols without documentation—preparation heterogeneity is a major concern 1.

Safety Profile

No severe adverse events were reported across multiple studies 2, 3, 5, establishing PRP as a safe intervention when properly prepared and administered.

Practical Algorithm for Decision-Making

For knee OA with mild-to-moderate degeneration:

• Use leukocyte-poor PRP preparation 2
• Administer intra-articular injection (single dose may suffice) 3
• Expect 6-9 months of benefit 3, 4
• Consider younger patients with less advanced disease as ideal candidates 4

For hip OA:

• Do not use PRP—evidence shows no benefit 2

For ankle or TMJ OA:

• Consider PRP as evidence supports efficacy 2

For advanced knee OA or patients near joint replacement:

• Do not use PRP—efficacy decreases with disease severity 4

Cost-Effectiveness

PRP treatment costs less than hyaluronic acid therapy while providing superior outcomes 3, making it an economically favorable option when indicated.