Platelet-Rich Plasma (PRP) Injections: Indications and Procedures
Primary Clinical Indications
PRP injection is most strongly recommended for general wound healing, with established evidence supporting its use in facial aesthetics (melasma, periorbital rejuvenation, skin aging), and moderate evidence for lateral epicondylitis and knee osteoarthritis. 1, 2
Strongly Supported Indications
General wound healing receives the highest recommendation from the International Society on Thrombosis and Haemostasis (median expert score 7/9), based on PRP's ability to release growth factors and cytokines that stimulate tissue repair 1, 2
Facial aesthetic applications show robust evidence:
- Melasma treatment: PRP injections significantly improved melasma within 6 weeks, with total efficacy of 90.48% and lower recurrence rates at 3-6 months compared to controls 1
- Periorbital rejuvenation: Improvement in dark circles (47.8-60.9%) and wrinkles (73.9-78.3%) at 3-6 months follow-up 1
- Skin aging: When combined with hyaluronic acid (50:50 mix), PRP showed 20-24% improvement in facial appearance scores at 1-6 months 1
Knee osteoarthritis: Statistically significant reduction in pain (VAS), improved functional scores (WOMAC, KSS) maintained at 6 months follow-up 3, 4
Lateral epicondylitis: Leukocyte-rich PRP (LR-PRP) has abundant high-quality evidence supporting its use 4
Indications with Uncertain Evidence
The International Society on Thrombosis and Haemostasis rates the following as uncertain (median scores 4-6.5/9): 1
- Burn injuries
- Tendon injuries (general)
- Acute muscle injuries
- Bone healing
- Maxillofacial injuries
- Sports injuries
- Osteoarthritis (non-knee joints)
Contraindicated or Ineffective Applications
Do not use PRP for: 4
- Achilles tendinopathy
- Acute muscle injuries
- Acute fractures or nonunion
- Surgical augmentation in rotator cuff repair
- Achilles tendon repair
- ACL reconstruction augmentation
Preparation Protocol
Anticoagulant Selection
Always use trisodium citrate as the anticoagulant—never use EDTA. 5
- Trisodium citrate is the most widely used with few negative effects 5
- EDTA causes platelet swelling and premature activation, negatively affecting platelet function 5, 6
Centrifugation Parameters
The preparation method significantly impacts clinical efficacy: 6
- Single spin protocols: 1200-3500 rpm for 4-15 minutes (varies by commercial kit) 1
- Double spin protocols: First spin 1200 rpm, second spin 2000-4000 rpm 1
- Critical caveat: Different g-force and centrifugation times result in significant variations in platelet yields, concentration, purity, viability, and activation status 6, 2
Classification System
Use the International Society on Thrombosis and Haemostasis classification to standardize documentation: 1
Key parameters to specify:
- Leukocyte content: L-PRP (leukocyte-rich, >1%) vs. PRP (leukocyte-poor, <1%)
- Red blood cell content: Red-PRP (>10% RBCs) vs. standard PRP
- Activation method:
- Class I: No activator
- Class II: With activation (calcium chloride, thrombin)
- Class III: Alternative activation
- Platelet concentration:
- Class A: 2-5× baseline
- Class B: 5-9× baseline
- Class C: >9× baseline
- Preparation technique: (1) gravitational centrifugation, (2) cell separators, (3) filtration technology
Administration Procedures
Facial Aesthetic Applications
For melasma: 1
- Intradermal injection technique
- 4 treatment sessions every 2-3 weeks
- Follow-up at 1 month after last treatment
- Expect 45-54% reduction in MASI scores
For periorbital rejuvenation: 1
- Point-by-point intradermal injections into tear trough and crow's feet
- 2-4 sessions, 1 month apart
- 1.5 mL PRP per side per session
- Follow-up at 3-6 months
For general facial rejuvenation: 1
- Consider combining PRP with hyaluronic acid (50:50 mix) for enhanced results
- Alternative: Combine with nanofat grafting for superior long-term outcomes (effects maintained at 12 months vs. HA alone)
Orthopedic Applications
For knee osteoarthritis: 3
- Three consecutive intra-articular injections
- Spacing not specified in highest quality evidence, but typically 1-2 weeks apart
- Evaluate at 1,3, and 6 months post-treatment
- Use ultrasound guidance for accurate delivery 2
For lateral epicondylitis: 4
- Use leukocyte-rich PRP (LR-PRP) formulation specifically
- Intratendinous injection under ultrasound guidance
- Typically 1-3 injections
Mechanism of Action
PRP works through multiple pathways: 5, 6, 2
- Release of growth factors from platelet α-granules upon activation
- Promotion of angiogenesis (new blood vessel formation)
- Stimulation of cell migration, proliferation, and differentiation
- Enhanced collagen deposition and organization
- Creation of fibrin scaffold serving as temporary 3D matrix for tissue repair
- Increased dermal thickness and fibroblast activity (in dermatologic applications)
Critical Pitfalls to Avoid
Standardization failure: The field suffers from severe lack of standardization in preparation methods, making comparison between studies difficult 1, 6, 2
- Always document exact preparation parameters using the classification system above
- Recognize that different preparation techniques yield vastly different products
Anticoagulant error: Using EDTA instead of trisodium citrate compromises platelet function 5, 6
Unrealistic expectations: Effects may diminish over time, requiring maintenance treatments 5
- For facial aesthetics, effects typically last 3-6 months 1
- Set patient expectations accordingly
Monotherapy assumption: PRP should be combined with appropriate rehabilitation or adjunctive treatments 2
- For orthopedic injuries, structured rehabilitation is essential
- For facial aesthetics, consider combination with HA or other modalities
Inadequate quality control: Future trials must include content and quality control of platelet preparations to ensure clear correlations between products and outcomes 1
Safety Profile
PRP is considered safe, cost-effective, and minimally invasive due to its autologous nature. 2, 7