PRP (Platelet-Rich Plasma) — Autologous Regenerative Therapy — Regenerative Therapies
Autologous blood product concentrated in platelets and growth factors. Moderate evidence for musculoskeletal healing applications.
Overview
Platelet-Rich Plasma (PRP) is an autologous blood product prepared by centrifuging a patient's own blood to concentrate platelets and their associated growth factors. Platelets contain alpha-granules that release a cocktail of bioactive proteins including PDGF, TGF-beta, VEGF, EGF, IGF-1, and FGF upon activation. These growth factors collectively promote tissue repair, angiogenesis, collagen synthesis, and cell proliferation. PRP preparation involves drawing 15-60 mL of whole blood, centrifuging it to separate platelet-rich layers, and injecting the concentrate directly into the target tissue. There is significant variability in PRP preparations depending on centrifugation protocols, platelet concentration (2-8x baseline), leukocyte content (leukocyte-rich vs leukocyte-poor), and activation method. This preparation variability has contributed to inconsistent clinical trial results. Current evidence supports PRP for knee osteoarthritis (multiple meta-analyses showing superiority over hyaluronic acid and placebo at 6-12 months), lateral epicondylitis (tennis elbow), and chronic tendinopathies. Evidence for rotator cuff repair, ACL reconstruction augmentation, and muscle injuries is mixed. PRP is generally considered safe due to its autologous nature (no immune rejection or disease transmission risk). The FDA classifies PRP as a minimally manipulated autologous blood product, not requiring approval as a drug, though it regulates PRP device manufacturers.
Indications
- Evidence-supported: Knee osteoarthritis (multiple meta-analyses positive)
- Evidence-supported: Lateral epicondylitis (tennis elbow)
- Evidence-supported: Chronic tendinopathies (patellar, Achilles)
- Emerging evidence: Rotator cuff repair augmentation
- Emerging evidence: Androgenetic alopecia (hair restoration)
- Emerging evidence: Wound healing and skin rejuvenation
Mechanism of Action
Centrifugation concentrates platelets 2-8x above baseline, creating a growth factor-rich preparation
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| PRP | 3-6 mL | 1-3 injections, 2-4 weeks apart | Knee osteoarthritis protocol; leukocyte-poor PRP preferred |
| PRP | 2-3 mL | 1-2 injections, 4-6 weeks apart | Tendinopathy protocol; ultrasound-guided |
| PRP | 1-2 mL | Monthly x 3, then every 3-6 months | Alopecia / aesthetic protocol |
Evidence Grade
GRADE C
Safety & Contraindications
- Excellent safety profile — autologous product, no immune rejection risk
- Injection site pain, swelling, and bruising common (temporary)
- Infection risk (standard injection precautions)
- May cause temporary flare of inflammation at injection site (1-3 days)
- Results highly dependent on preparation method and PRP quality
- Not covered by most insurance plans
- Variability between clinics in preparation protocols