What are the indications and treatment protocols for Platelet-rich Plasma (PRP) therapy?

Platelet-Rich Plasma (PRP) Therapy: Indications and Treatment Protocols

PRP therapy has established efficacy in ophthalmology for proliferative diabetic retinopathy and shows promise in aesthetic dermatology (androgenetic alopecia, facial rejuvenation, melasma), but lacks sufficient evidence for orthopedic applications like knee and hip osteoarthritis where major guidelines recommend against its use.

Established Clinical Indications

Ophthalmology: Proliferative Diabetic Retinopathy (PDR)

• PRP (panretinal photocoagulation) substantially reduces severe visual loss in high-risk PDR and should be performed expeditiously 1
• The ETDRS protocol involves 1200-1600 moderate burns, 0.1 second duration, one-half burn width apart, at least 2 disc diameters from fovea to equator 1
• Anti-VEGF injections (ranibizumab) are noninferior to PRP at 2 years, but patients lost to follow-up have inferior outcomes compared to PRP 1
• Anti-VEGF should only be considered for patients with reliable follow-up; otherwise PRP is preferred 1
• For type 2 diabetes with severe NPDR to non-high-risk PDR, early PRP reduces severe vision loss/vitrectomy by 50% (2.5% vs 5%) 1

Dermatology and Aesthetic Medicine

Androgenetic Alopecia (AGA)

• Combined PRP with minoxidil is more effective than minoxidil monotherapy 1
• Non-activated PRP shows greater increase in hair count and total hair density (31%) than activated PRP 1
• Treatment protocol: 3-4 intradermal scalp injections spaced 2-4 weeks apart, with follow-up at 3-6 months 1
• Higher platelet concentrations result in greater effects on hair density, follicle diameter, and terminal hair density 1
• PRF (platelet-rich fibrin) shows clinical efficacy with improvements in hair growth, particularly in mild cases 1
• Caveat: Evidence quality is limited by variable protocols, small sample sizes, and lack of standardization 1

Facial Rejuvenation and Skin Aging

• PRP demonstrates efficacy for fine wrinkling, color homogeneity, and skin texture in photoaged skin 1
• Treatment protocol: 3 intradermal injections spaced 21-30 days apart 1
• Combination with hyaluronic acid shows superior results to either substance alone 1
• PRF shows marginal superiority over PRP for canthal region treatment at 3 months 1
• Common pitfall: Treatment regimens remain non-standardized with variable dosing and session numbers 1

Periorbital Rejuvenation

• PRP shows promise for periorbital hyperpigmentation (POH) and periocular wrinkles with high patient satisfaction 1
• Administration: Microneedling at 0.25mm depth or intradermal papule injection 1
• Two sessions of plasma gel show significantly better results than PRP for periorbital rejuvenation 1
• Significant increase in skin firmness and elasticity measured by cutometer 1

Melasma

• PRP combined with oral tranexamic acid (250mg twice daily) is superior to tranexamic acid alone 1
• Treatment protocol: Monthly intradermal PRP injections for 3 months 1
• Mean MASI score reduction of 45-54% with high patient satisfaction 1
• Disease recurrence rate lower in PRP combination group at 3 and 6 months 1

Contraindicated or Insufficient Evidence

Orthopedic Applications

Knee Osteoarthritis

• The American College of Rheumatology/Arthritis Foundation strongly recommends AGAINST PRP use for knee osteoarthritis 2
• The AAOS notes inconsistency in evidence with worse treatment responses in severe knee OA 2
• Medicare does not cover PRP for knee pain based on these guideline recommendations 2
• Recommended alternatives: Physical therapy, weight management, NSAIDs, intra-articular corticosteroid injections 2

Hip Osteoarthritis

• The ACR/AF 2019 guidelines recommend against PRP for hip osteoarthritis 3
• The VA/DoD 2020 guidelines state insufficient evidence due to inconsistent study results 3
• No significant difference between PRP and hyaluronic acid for hip OA at all follow-up periods 3
• First-line treatments should be physical therapy, weight management, and NSAIDs before considering any injections 3

Critical Limitations Across All Applications

Lack of Standardization

• Clinical preparations of PRP are poorly standardized, with complete expert panel agreement 1
• Content, purity, and biological properties vary widely and impact clinical efficacy 1
• Most trials fail to fully define content, purity, and biological properties of platelet preparations 1
• Platelet concentration, yield, and recovery depend on centrifugation protocol and collection methods 1

Preparation Guidelines

• EDTA anticoagulant should NOT be used for PRP preparation 1
• Citrate or ACD anticoagulation preferred, though optimal choice remains uncertain 1
• Autologous/allogeneic sterile PRP preparations are clinically safe 1
• Whether PRP requires activation before application remains uncertain 1
• Collagen-rich tissues may activate PRP, eliminating need for pre-application activation 1

Research Quality Issues

• Clinical trials must include: randomized placebo-controlled design, clear inclusion/exclusion criteria, standardized assessments, validated production methods, and full description of PRP preparation methodology 1
• Heterogeneity in PRP preparations makes sweeping recommendations impossible 4
• Limited availability of large randomized clinical trials across most indications 5

Evidence Hierarchy Summary

Strong evidence (use recommended):

• Proliferative diabetic retinopathy (ophthalmologic PRP/panretinal photocoagulation) 1

Moderate evidence (may consider with informed consent):

• Androgenetic alopecia combined with minoxidil 1
• Facial rejuvenation for photoaging 1
• Melasma combined with tranexamic acid 1

Insufficient evidence (NOT recommended by major guidelines):

• Knee osteoarthritis 2
• Hip osteoarthritis 3
• General orthopedic injuries 6

The fundamental problem is that "PRP therapy" encompasses vastly different preparations and applications—from laser photocoagulation in ophthalmology to autologous platelet injections in dermatology—making unified recommendations impossible without specifying the exact indication and preparation method.