Do platelet-rich plasma (PRP) injections help treat tendinosis?

Efficacy of PRP Injections for Tendinosis Treatment

PRP injections show promising results for treating tendinosis, with leukocyte-rich PRP preparations demonstrating the strongest positive effects, though standardization of preparation techniques remains a significant challenge. 1

Mechanism of Action

• PRP contains concentrated platelets and growth factors that stimulate tissue repair by promoting angiogenesis, cell migration, proliferation, and collagen deposition 2
• Histopathological studies demonstrate that PRP treatments lead to increased dermal thickness, neocollagenosis, enhanced collagen organization, and increased fibroblast activity 3, 2
• PRP stimulates cell proliferation and expression of type I collagen in human dermal fibroblasts, contributing to tissue regeneration 2

Evidence for Efficacy in Tendinosis

• Meta-analysis of randomized controlled trials shows that leukocyte-rich PRP (LR-PRP) preparations have stronger positive effects (SMD 36.38) compared to leukocyte-poor PRP (SMD 26.77) in treating tendinopathy 1
• Ultrasound-guided intratendinous injection technique appears to be clinically significant for optimal outcomes 1
• Two consecutive PRP injections for chronic patellar tendinopathy showed significantly better improvement in outcomes compared to a single injection, with better VAS scores (1.07 vs 3.7), Tegner scores (8.1 vs 5.9), and VISA-P scores (93.2 vs 65.7) 4

Conflicting Evidence

• Some randomized controlled trials found ultrasound-guided PRP injections to be no more effective than saline for patellar tendinopathy when combined with exercise-based rehabilitation 5
• A comparative study between PRP and corticosteroid injections for rotator cuff tendinopathy showed no significant differences in outcomes over 18 months, though both treatments improved patient symptoms 6
• The field is plagued with poor standardization and variability in methods used to generate PRP, with inconsistency in terminology, purity, content, and quality of products 3

Preparation Considerations

• Trisodium citrate is the most widely used anticoagulant for PRP preparation with few negative effects 3
• EDTA should not be used for PRP preparation as it causes platelet swelling and activation 3, 7
• Platelet concentration, yield, and recovery are dependent on the centrifugation protocol and collection methods utilized 7

Clinical Application Guidelines

• Ultrasound guidance for injection is recommended for optimal placement of PRP within the tendon 1
• For chronic tendinopathy, consider two consecutive PRP injections rather than a single injection for better outcomes 4
• Leukocyte-rich PRP preparations appear to have stronger therapeutic effects than leukocyte-poor preparations for tendinopathy 1

Limitations and Challenges

• Lack of standardization in PRP preparation techniques, dosing protocols, and outcome measurements makes comparison between studies difficult 3, 2, 7
• Heterogeneous study designs lead to varying conclusions about efficacy 2
• Effects may diminish over time, requiring maintenance treatments 2

Common Pitfalls to Avoid

• Using EDTA as an anticoagulant in PRP preparation can negatively affect platelet function 3, 7
• Single injections may be less effective than multiple injections for chronic cases 4
• Failure to use ultrasound guidance may result in suboptimal placement and reduced efficacy 1
• Not considering the leukocyte content of the PRP preparation, as leukocyte-rich preparations show better outcomes for tendinopathy 1