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Regenerative Research Roundup - February 2026

Welcome to the Regenerative Research Roundup, where we look through recently published research and bring you the best of the best in a quick-to-read digest.

 

This month, we explore:

  • Consensus on post-PRP protocols for chronic tendinopathy

  • PRP dose thresholds and their impact on clinical outcomes

  • Biological differences between PRP and i‑PRF

  • PRP as an adjunct to microfracture for chondral lesions

  • How diet may influence LP‑PRP cytokine composition

 

Let's dive in!



Rehabilitation and Return to Activity After Platelet‑Rich Plasma Injections in Chronic Tendinopathies: Consensus From International Experts


PM&R // LOE: V


An international Delphi‑based consensus of 23 experts, established standardized rehabilitation protocols post-PRP injection for chronic tendinopathies, including healing timelines, loading progression, and return‑to‑sport criteria. 10 of 14 expert-opinion driven recommendations deemed appropriate.


Key Findings:

  • Experts strongly agree that NSAIDs should be avoided for the first few weeks post-PRP injection for chronic tendinopathy

  • Experts strongly agree that tendon rehabilitation should begin 5-10 days post injection of PRP for chronic tendinopathy

  • Experts strongly agree it’s appropriate to consider a gradual return to professional or sporting activities when clinical examination demonstrates little/no pain (VAS score below <3/10)

  • Experts strongly agree that a second injection may be considered in cases of partial improvement after 3 months post-injection


Clinical Perspective:


Due to insufficient clinical data, expert opinions weigh heavily here. However, it successfully outlines clear recommendations and standardized protocols of post-injection PRP for chronic tendinopathy from emerging literature and in clinical practice – addressing a diverse aspect, such as correlating VAS scores with stages in recovery, outlining the need for physiotherapy and exercise routines, and the need for NSAIDs for pain reduction and healing tendons. Post-PRP rehabilitation is a critical determinant of treatment success that is often overlooked or mismanaged.


For sports‑MSK clinics, the core takeaways are:

  • Early‑phase loading (days 5–10) is safe and supported.

  • Avoid NSAIDs to protect platelet‑driven regenerative pathways.

  • Pain‑guided progression (VAS ≤3/10) remains the best‑supported load metric.



Monthly Multiple Injections of Leukocyte‑Poor Platelet‑Rich Plasma (ACP®) for Knee Osteoarthritis: Dose‑Response Plateau at Four Injections & 24‑Month Durability


Regenerative Therapy // LOE: II


Retrospective analysis of 158 knee OA (KL1–4) from a single clinic, treated with prospective planned monthly injections of LP‑PRP (Arthrex ACP®), receiving fixed doses of (3 mL or 6 mL) monthly up to six sessions, with follow‑up out to 24 months.


Key Findings

  • Significant pain improvement from baseline at 12 months (ΔVAS ~32.5) and sustained at 24 months (ΔVAS ~38) across all KL grades with no clear advantage of 6mL injection over 3mL.

  • ΔKOOS displayed improvement at 12 months, persisting to 24 months. OMERACT-OARSI responder rates were high at 12 and 24 months across KL grades and structural improvement (MRI bone marrow lesions) decreased at 12 months.  

  • Longitudinal dose‑response supported a breakpoint at the 4th injection with no additional robust benefit beyond 4–5 injections.


Clinical Perspective:


While positive outcomes were achieved across all time points, albeit in a non-randomized retrospective analysis, this study primarily demonstrates the ceiling and practical limitations of low-dose PRP systems. It is representative of how clinicians and researchers approach the use of these systems in clinical practice to achieve better outcomes - which is to throw more of it at the problem over repeated injections OR in greater volume. Often at the expense of patient comfort, administrative scheduling, and overall treatment cost.


Authors used the Arthrex ACP system - reporting platelet concentrations of 2.4-2.6x baseline. And while they did not report baseline PLT counts, we can estimate patients only received doses of 1.8B platelets for the 3 mL and 3.9B platelets for the 6 mL injections. This falls well below optimal PLT threshold for significant joint-tissue response, now being reported at 10B platelets in recent clinical literature (Bansal, 2022). This threshold of total platelet exposure @ 10B  PLTs was only surpassed in the 6ml group after 3 injections. And was never met in the 3ml group.


As with all PRP studies of this nature, the problem lies in the repeated use of sub-therapeutic PRP dosages. How would outcomes have changed if proper dosages were delivered in monthly intervals?


Furthermore, why subject a patient to 4-6 injections to achieve what a high-dose PRP can achieve in 1-2 injections? Patients typically find the process of intaking needles to be rather uncomfortable. Therefore, receiving both intra-articular injections and blood drawing on a monthly basis, and six follow-ups may discourage both clinicians from practicing and patients from being willing to receive PRP.


To avoid this problem, do not assume you can over-correct a low-dose PRP system by injecting more volume or in greater frequency. Rather, start with the correct solution first to improve patient comfort, ease administrative burden, reduce cost, and achieve optimal outcomes.

 


Comparative Characterization of Leukocyte‑Rich Platelet‑Rich Plasma (L‑PRP) and Injectable Platelet‑Rich Fibrin (i‑PRF): A Laboratory Study


Preprints // LOE: V


A laboratory characterization study of 34 healthy donors comparing L‑PRP (double‑spin, anticoagulated) vs i‑PRF (low‑speed, no anticoagulant) focused on cellularity, final product volume, and PDGF‑BB concentration.


Key Findings:

  • Platelet concentration & dose: PRP displayed a significantly higher platelet concentration than i-PRF (6.1x baseline vs 1.8x baseline) and delivered more total platelets (4B platelets vs 3.3B platelets).

  • Leukocyte concentration: PRP displayed a significantly higher leukocyte concentration than i-PRF (3.1x baseline vs 1.9x baseline)

  • Growth Factors PDGF-BB concentration: PRP had a much higher PDGF-BB concentration than i-PRF (13.3x higher than i-PRF).

Figure 2. Box plot showing platelet count across baseline, platelet-rich plasma (PRP), and injectable platelet-rich fibrin (i-PRF). The black square represents the mean, and the median is displayed with the 95% confidence interval (±95% CI).

 

Clinical Perspective:


This laboratory study demonstrates that in a head-to-head comparison between L‑PRP and i‑PRF, where a proper dual-spin PRP system is used, they produce fundamentally different biological products.


This study shows unequivocal evidence that a dual-spin PRP system delivers vastly higher platelet concentrations, platelet doses, and growth factor levels – which directly impact efficacy, patient outcomes and return to function. Single-spin systems like the PRF complete the entire preparation in one centrifuge cycle, because PRF uses no anticoagulant, the blood must begin clotting naturally as part of the process. This results in lower platelet concentrations, lower platelet dose and lower growth factor levels compared to dual-spin PRP.


Overall, this study reinforces that PRF fails to compete with dual-spin PRP systems in a head-to-head, in-terms of platelet dosing and growth factor levels. Therefore, for MSK, sports medicine, pain management, and injections requiring precise dosing and rich compositions, dual-spin PRP systems are the favored practice for clinicians. 



Effectiveness of Platelet‑Rich Plasma Plus Microfracture Compared With Microfracture Alone in the Treatment of Knee Cartilage Lesions: A Systematic Review and Meta‑analysis of Comparative Studies


International Journal of Surgery // LOE: II (Systematic Review & Meta‑analysis)


Meta-analysis consisting of 11 studies (664 patients) comparing PRP in combination with Microfracture (MF) vs MF alone for knee chondral lesions. Included 6 randomized control trials (RCT) and 5 cohort studies with follow‑up up to 24 months.


Key Findings:

  • The PRP concomitant with MF group displayed significantly improved VAS scores at the 3, 12, and 24 months compared to the MF cohort.

  • The PRP concomitant with MF group displayed significantly improved Lysholm scores at 3, 6, 12, 24 months compared to the MF cohort.

  • The PRP concomitant with MF group displayed significantly improved IKDC score at 24 months compared to MF cohort


Clinical Perspective:


From an orthopedic perspective, this meta‑analysis reinforces a consistent finding that PRP used as a biologic adjunct enhances cartilage repair procedures and microfractures, by improving pain and functional outcomes over 24 months. The improvements measured in VAS, Lysholm, and IKDC scores across multiple timepoints pinpoint PRP’s role in supporting early recovery and sustained symptom relief over the long-term.


Importantly, most included studies used low‑dose PRP systems, which typically yield a suboptimal platelet dose ranging from 2–3 billion platelets per treatment – proving that even low dose PRP systems were sufficient to improve pain scores and show cartilage repair. While these doses proved to demonstrate clinical benefit, they fall well below the therapeutic targets supported by current biologic literature. We speculate using a dual-spin PRP system delivering higher platelet doses would see a much greater improvement in pain scores and potentiate greater clinical outcomes in the orthopedic space.


Overall, this study strengthens the evidence that PRP meaningfully augments cartilage repair procedures, and clinicians should ensure their PRP systems reliably deliver therapeutic platelet doses when using PRP alongside surgical or minimally invasive cartilage‑restoration strategies.



Dietary Patterns Are Associated With Molecular Composition of Leukocyte‑Poor PRP


Nutrients // LOE: III


Cross‑sectional analysis of 75 healthy adults (vegan, vegetarian, omnivore) assessing how habitual diet influences LP‑PRP cytokine and growth‑factor composition.


Key Findings:

  • Platelet counts, Erythrocytes and Leukocytes ratios were unchanged across diet types, with LP‑PRP remained leukocyte‑poor across all subjects regardless of diet.

  • Higher Animal‑Based Diet Score correlated with higher PRP IL‑6, with PRP IL-6 being significantly lower in vegans vs omnivores.

  • PDGF‑BB correlated positively with meat intake and inversely with fruit/vegetable intake.

  • No major differences observed for IGF‑1 or HGF across diet groups.


Clinical Perspective:


Although not a clinical outcomes study, this observational study highlights that donor factors such as diet can shift PRP composition, even when platelet yield remains unchanged.


A few trends were observed across the data such as higher inflammatory signatures (e.g., IL‑6) appear in animal‑based diets, plant dominant diets yielding lower-inflammatory signals without altering dosing capacity – which may be a clinical consideration when treating patients with inflammatory joint disease, as baseline cytokine load and composition influences PRP quality.


Overall, this does not change clinical dosing recommendations or imply that dietary changes improve PRP results but may help set realistic expectations about inter-patient variability – however observational studies correlating patient outcomes with diet is needed for further characterization.



 
 
 

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