Platelet-Rich Plasma

A Single Injection of Platelet-Rich Plasma Injection for the Treatment of Stress Urinary Incontinence in Females: A Randomized Placebo-Controlled Trial

OBJECTIVE

To determine the efficacy of a single injection of platelet-rich plasma into the anterior vaginal wall at the mid-urethra compared to placebo, as there is emerging evidence that platelet-rich plasma may help treat female stress urinary incontinence.

METHODS

This was a single-blind, randomized, placebo-controlled clinical trial at a single institution. Females with bothersome, demonstrable stress-predominant urinary incontinence were enrolled. Participants were randomized to either injection of 5 mL autologous platelet-rich plasma or saline at the anterior vaginal wall at the mid-urethra. The primary outcome was composite treatment success at six months, defined as a negative cough stress test and an answer of "much better" or "very much better" on the Patient's Global Impression of Improvement.

RESULTS

Fifty patients were enrolled in the study and randomized to the platelet-rich plasma group (n = 25) or the saline placebo group (n = 25). There was no statistically significant difference in the primary outcome between the two groups. Adverse events were minor, and the rate of adverse events was similar between both groups.

CONCLUSIONS

In this randomized placebo-controlled study, we were unable to demonstrate a difference in stress urinary incontinence treatment success between platelet-rich plasma and saline injections. At this time, there is insufficient evidence to offer a one-time platelet-rich plasma injection into the anterior vaginal wall for treatment of female stress urinary incontinence.

Efficacy of Intra-Articular Corticosteroid Injection for Nonsurgical Management of Trapeziometacarpal Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

PURPOSE

As osteoarthritis (OA) of the trapeziometacarpal (TMC) joint leads to a high degree of disease burden with compromises in rudimentary and fine movements of the hand, intra-articular injections may be a desirable treatment option. However, because there are no evidence-based guidelines, the choice of intra-articular injection type is left to the discretion of the individual surgeon in collaboration with the patient. The purpose of our study was to perform a systematic review and meta-analysis using level I studies to compare outcomes following corticosteroid and alternative methods of intra-articular injections for the management of TMC OA. Our hypothesis was that intra-articular corticosteroid injections were no more effective than other methods of intra-articular injections for the management of TMC OA.

METHODS

A systematic literature search was performed. Eligible for inclusion were randomized control trials reporting on intra-articular corticosteroid injection for the management of TMC OA. Clinical outcomes were recorded.

RESULTS

The 10 included studies comprised 673 patients. The mean age was 57.8 ± 8.3 years, with a mean follow-up of 6.4 ± 2.7 months. There was no significant difference in visual analog scale scores, grip strength and tip pinch strength between corticosteroids and hyaluronic acid at short- and medium-term follow-up. Further, there was no difference in visual analog scale pain scores at rest at medium-term follow-up between corticosteroids and platelet-rich plasma.

CONCLUSIONS

Despite short-term improvement with intra-articular corticosteroid injections, there was no significant difference in pain and functional outcomes following intra-articular corticosteroid injections compared to hyaluronic acid or platelet-rich plasma administration. Given the affordability, ease of administration, and efficacy associated with corticosteroids, they are a favorable option when considering the choice of intra-articular injection for the management of TMC OA.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Platelet-rich plasma alleviates knee arthritis in rats by inhibiting p65

Knee osteoarthritis (KOA) is a chronic joint disease characterized by the degeneration of articular cartilage. In this study, we explored the potential therapeutic effects of platelet-rich plasma (PRP) and identified molecular targets for treating KOA. A rat model of KOA was established via the Hulth method and primary knee joint chondrocytes were isolated to evaluate the effects of PRP and shRNA targeting p65 (sh-p65). ELISA was used to detect inflammatory factors, including IL-6, IL-1β, and TNF-α. HE staining, Safranin O/Fast Green staining and Masson staining were performed to evaluate the morphology of articular cartilage, followed by detection of p65, COL2A1, ACAN, MMP13, and ADAMTS5 expression. The proliferation and apoptosis of primary knee chondrocytes were detected by the CCK-8 assay and TUNEL staining, respectively. Treatment with either PRP or sh-p65 decreased IL-6, IL-1β, and TNF-α levels in the peripheral blood of KOA rats and chondrocyte culture supernatants, increased COL2A1 and ACAN levels, and decreased MMP13 and ADAMTS5 expression. Furthermore, administration of PRP or sh-p65 exerted protective effects on articular cartilage, enhanced the vitality of knee joint chondrocytes, and inhibited apoptosis. Collectively, PRP inhibited inflammation, promoted chondrocyte proliferation and cartilage matrix secretion, and induced cartilage regeneration by suppressing p65 expression; these effects allow PRP to alleviate KOA progression. P65-based targeted therapy administered in combination with PRP might be a promising strategy for treating KOA.

Postinjection protocols following platelet-rich plasma administration for knee osteoarthritis: A systematic review

OBJECTIVE

Platelet-rich plasma (PRP) use in treating orthopedic conditions has increased, yet evidence of its clinical efficacy is inconsistent and limited by heterogeneity in osteoarthritis (OA) severity, PRP preparations and protocols, and clinical outcome measurement. This review aims to characterize the variations in postinjection protocols in studies assessing the clinical efficacy of PRP for knee OA.

LITERATURE SURVEY

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search from database inception to February 2023 of CINAHL, MEDLINE, and EMBASE was conducted.

METHODOLOGY

Article screening, data extraction, and risk of bias assessments were completed in duplicate by two reviewers. Primary outcomes were presence/absence and timing of the following postinjection protocol components: nonsteroidal anti-inflammatory drug (NSAID) restrictions, non-NSAID analgesic and cryotherapy use, immediate knee flexion/extension, immediate rest, activity restriction, return-to-activity guidelines, and rehabilitation protocols. A descriptive analysis was used to analyze the data. Given study heterogeneity, a meta-analysis was not performed.

SYNTHESIS

A total of 187 studies were included for analysis. Half of all studies (51.9%) excluded patients due to preinjection NSAID use, most often within 5 days of blood sampling or injection. Postinjection NSAID restriction was included in 42.8% of studies, ranging from 1 to 1800 days. Few studies (19.4%) that permitted non-NSAID analgesia restricted their use prior to clinical assessments. Postinjection immediate flexion, extension, and immobilization were rarely (8.6%) mentioned. Activity restriction was included in a third of studies (35.3%), with the most frequent length of restriction being 1 day. Postinjection return-to-activity protocols were less common (20.3%), usually with a "gradual" and/or "as tolerated" recommendation. A minority of studies (16.0%) reported physical therapy protocols and the vast majority (93.3%) were home based.

CONCLUSION

Significant heterogeneity remains in post-PRP injection protocols, with unclear consensus regarding optimal recommendations and limited rationale for the protocols outlined. Further study is necessary to compare protocols directly and to determine which pre- and postinjection recommendations can result in optimal outcomes.

The use of platelet-rich plasma in pathologies of the foot and ankle: A comprehensive review of the recent literature

Platelet-rich plasma (PRP) is an autologous serum containing higher concentrations of platelets and growth factors above normal blood. The process of obtaining PRP involves the extraction of blood from the patient which is then centrifuged to obtain a concentrated suspension of platelets. PRP continues to evolve as a potential treatment modality with many applications in orthopaedic surgery. The therapeutic components of PRP possess numerous theoretical regenerative properties. The present manuscript outlines how PRP is prepared, noting the tremendous variability between preparation protocols. Given the growing body of evidence examining the use of PRP in pathologies of the foot and ankle, we assess its efficacy as it relates to our field. Specifically, we evaluate the literature in the past five years regarding the role of PRP in treating plantar fasciitis, Achilles tendinopathy, insertional Achilles tendinitis, Achilles tendon ruptures, osteochondral lesions of the talus, hallux rigidus, and ankle osteoarthritis.

Effect of intrauterine infusion of platelet-rich plasma for women with recurrent implantation failure: a systematic review and meta-analysis

This study evaluated the effect of intrauterine perfusion of autologous platelet-rich plasma (PRP) on pregnancy outcomes in women with recurrent implantation failure (RIF). Key biomedical databases were searched to identify relevant clinical trials and observational studies. Outcomes included clinical pregnancy rate, chemical pregnancy rate, implantation rate, live birth rate, and abortion rate. Data was extracted from ten studies (six randomised controlled trials, four cohort studies) involving 1555 patients. Pregnancy outcomes were improved in women treated with PRP compared to controls: clinical pregnancy rate (RR = 1.96, 95% CI [1.67, 2.31], p < 0.00001, I² = 46%), chemical pregnancy rate (RR = 1.79, 95% CI [1.54, 2.08], p < 0.00001, I² = 29%), implantation rate (RR = 1.90, CI [1.50, 2.41], p < 0.00001, I² = 0%), live birth rate (RR = 2.83, CI [1.45, 5.52], p = 0.0007, I² = 83%), abortion rate (RR = 0.40, 95% CI [0.18, 0.90], p = 0.03, I² = 59%). These data imply PRP has potential to improve pregnancy outcomes in women with RIF, suggesting a promising role in assisted reproductive technology.IMPACT STATEMENTWhat is already known on this subject? Platelet-rich plasma (PRP) is an autologous blood product that contains platelets, various growth factors, and cytokines at concentrations above the normal baseline level. Recent studies have shown that intrauterine infusion of autologous PRP can improve pregnancy outcomes in infertile women.What do the results of this study add? This systematic review and meta-analysis of data from ten studies (n = 1555; 775 cases and 780 controls) investigated the effect of intrauterine perfusion of autologous PRP on pregnancy outcomes in women with recurrent implantation failure (RIF). Findings suggest that pregnancy outcomes, including clinical pregnancy rate, chemical pregnancy rate, implantation rate, live birth rate and abortion rate were improved in women treated with PRP compared to controls.What are the implications of these findings for clinical practice and/or further research? RIF remains a challenge for researchers, clinicians, and patients. Our study identified PRP as a potential intervention in assisted reproduction. As an autologous blood preparation, PRP eliminates the risk of an immune response and transmission of disease. PRP is low cost and effective and may represent a new approach to the treatment of patients with RIF.

Clinical efficacy of botulinum toxin in lateral elbow tendinopathy: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Botulinum toxin injections for lateral elbow tendinopathy have been used as an alternative therapeutic option. However, few studies have quantitatively summarized the effect of botulinum toxin as well as its clinical significance. We aimed to evaluate the clinical efficacy (based on pain and grip strength) and adverse events of botulinum toxin on lateral elbow tendinopathy.

PATIENTS AND METHODS

The MEDLINE, EMBASE, Web of Science, and Scopus databases were searched until March 2023 for randomized controlled trials reporting the effects of botulinum toxin injections on lateral elbow tendinopathy. A random- or fixed-effects model (depending of inter-study variability) and generic inverse variance method were used to pool quantitative data from outcomes. The risk of bias was assessed with the Cochrane Risk of Bias 2.0 tool.

RESULTS

A total of 8 clinical trials recruiting 438 subjects were included for meta-analysis. Pooled analysis revealed that botulinum toxin significantly reduced pain (mean difference [MD] -0.95, 95% CI [-1.63, -0.26], p=0.007) but it was not clinically relevant. No significant effect was detected for grip strength (MD-0.62kg, 95% CI [-2.25, 1.02], p=0.46) or in the risk for adverse events (odds ratio [OR] 0.41, 95% CI [0.05, 3.56], p=0.42) between botulinum toxin injection and control interventions.

DISCUSSION

The use of botulinum toxin reached greater pain relief than control interventions and normal saline after a period of 12 to 24 weeks. However, changes in pain relief did not reach clinical significance. The studies that had the greatest reduction in pain used higher doses of botulinum toxin (60 U). Additionally, differences in grip strength and adverse events did not reach statistical or clinical importance. A subanalysis indicated that botulinum toxin outperformed corticosteroid injections in terms of improving grip strength. Botulinum toxin only causes local and minimal side effects such as irritation, ecchymosis, and paralysis.

LEVEL OF EVIDENCE

I.

Gluteal Tendinopathy: Critical Analysis Review of Current Nonoperative Treatments

» Gluteal tendinopathy/greater trochanteric pain syndrome (GTPS) is the most prevalent of all lower limb tendinopathies, affecting 1 in 4 women older than 50 years and commonly individuals within their fifth and sixth decades of life regardless of activity level.» The condition is believed to originate from age-related degenerative changes about the hip abductor tendon insertions and the surrounding bursae, and is exacerbated by congenital and acquired abnormal hip biomechanics.» Treatment of gluteal tendinopathy/GTPS often begins with noninvasive nonoperative modalities such as activity modifications, nonsteroidal anti-inflammatory drugs, and physical therapy. For recalcitrant symptoms, additional nonoperative therapies have been used; however, there remains a lack of comparative efficacy between these adjunct treatments.» In this article, we examine the available literature regarding the nonoperative management of gluteal tendinopathy/GTPS and provide insight into the effectiveness of current treatment modalities.

Platelet-derived biomaterial with hyaluronic acid alleviates temporal-mandibular joint osteoarthritis: clinical trial from dish to human

BACKGROUND

Bioactive materials have now raised considerable attention for the treatment of osteoarthritis (OA), such as knee OA, rheumatoid OA, and temporomandibular joint (TMJ) OA. TMJ-OA is a common disease associated with an imbalance of cartilage regeneration, tissue inflammation, and disability in mouth movement. Recently, biological materials or molecules have been developed for TMJ-OA therapy; however, ideal treatment is still lacking. In this study, we used the combination of a human platelet rich plasma with hyaluronic acid (hPRP/HA) for TMJ-OA therapy to perform a clinical trial in dish to humans.

METHOD

Herein, hPRP was prepared, and the hPRP/HA combined concentration was optimized by MTT assay. For the clinical trial in dish, pro-inflammatory-induced in-vitro and in-vivo mimic 3D TMJ-OA models were created, and proliferation, gene expression, alcian blue staining, and IHC were used to evaluate chondrocyte regeneration. For the animal studies, complete Freund's adjuvant (CFA) was used to induce the TMJ-OA rat model, and condyle and disc regeneration were investigated through MRI. For the clinical trial in humans, 12 patients with TMJ-OA who had disc displacement and pain were enrolled. The disc displacement and pain at baseline and six months were measured by MRI, and clinical assessment, respectively.

RESULTS

Combined hPRP/HA treatment ameliorated the proinflammatory-induced TMJ-OA model and promoted chondrocyte proliferation by activating SOX9, collagen type I/II, and aggrecan. TMJ-OA pathology-related inflammatory factors were efficiently downregulated with hPRP/HA treatment. Moreover, condylar cartilage was regenerated by hPRP/HA treatment in a proinflammatory-induced 3D neocartilage TMJ-OA-like model. During the animal studies, hPRP/HA treatment strongly repaired the condyle and disc in a CFA-induced TMJ-OA rat model. Furthermore, we performed a clinical trial in humans, and the MRI data demonstrated that after 6 months of treatment, hPRP/HA regenerated the condylar cartilage, reduced disc displacement, alleviated pain, and increased the maximum mouth opening (MMO). Overall, clinical trials in dish to human results revealed that hPRP/HA promoted cartilage regeneration, inhibited inflammation, reduced pain, and increased joint function in TMJ-OA.

CONCLUSION

Conclusively, this study highlighted the therapeutic potential of the hPRP and HA combination for TMJ-OA therapy, with detailed evidence from bench to bedside. Trial registration Taipei Medical University Hospital (TMU-JIRB No. N201711041). Registered 24 November 2017. https://tmujcrc.tmu.edu.tw/inquiry_general.php .

The Use of Intra-articular Platelet-Rich Plasma as a Therapeutic Intervention for Hip Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

There is a cohort of patients in whom hip preservation surgery is not indicated, because they have developed signs of early osteoarthritis (OA), and nor can they have a hip replacement, as they are too early in the disease process. Management of this cohort of patients is not standardised and both pharmacological and nonpharmacological measures are utilised to reduce pain. Interventions available for early OA include intra-articular injections of steroids, viscosupplementation and more recently platelet-rich plasma (PRP). However, the use of PRP in hip OA has not yet been studied systematically.

PURPOSE

To assess intra-articular PRP as a therapeutic intervention for hip OA, including the duration of efficacy, influence of dose and composition of PRP, and the incidence of adverse effects.

STUDY DESIGN

A systematic review and meta-analysis; Level of evidence, 4.

METHODS

We performed literature searches on the MEDLINE, EMBASE, CINAHL, WEB OF SCIENCE, COCHRANE, and SCOPUS databases, and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Data were pooled using random-effects meta-analysis. We assessed the quality of the included studies using the methodological index for non-randomized studies instrument, with an additional assessment for randomized controlled trials with the revised Cochrane risk of bias tool for randomized trials. This is the first study to concisely collate the available data on the use of PRP in hip OA.

RESULTS

Eight studies were included in the analysis, with data from a total of 331 patients. PRP significantly reduced pain compared with the baseline at multiple time points, with the greatest effect at the 1- to 2-month follow-up, but PRP significantly improved function only at the 1- to 2-month follow-up. A significantly larger reduction in pain was achieved with a single injection of PRP compared with multiple injections, a total injected dose of PRP <15 mL compared with ≥15 mL, and use of a leukocyte-poor PRP preparation compared with leukocyte-rich PRP. There were no lasting adverse effects.

CONCLUSION

Low- and moderate-quality evidence suggests that PRP reduces pain and improves function at the end-point follow-up of studies compared with the baseline. Moderate-quality evidence suggests that a larger reduction in pain is achieved with a single injection of PRP compared with multiple injections, and low-quality evidence attributes a larger reduction of pain with a total injected dose of PRP <15 mL compared with ≥15 mL and using leukocyte-poor PRP compared with leukocyte-rich PRP.

Aging Affects the Efficacy of Platelet-Rich Plasma Treatment for Osteoarthritis

OBJECTIVE

Despite the increased use of platelet-rich plasma in the treatment of osteoarthritis, whether and how age of the platelet-rich plasma donor affects therapeutic efficacy is unclear.

DESIGN

In vitro, male osteoarthritic human chondrocytes were treated with platelet-rich plasma from young (18-35 yrs) or old (≥65 yrs) donors, and the chondrogenic profile was evaluated using immunofluorescent staining for two markers of chondrogenicity, type II collagen and SOX-9. In vivo, we used a within-subjects design to compare Osteoarthritis Research Society International scores in aged mouse knee joints injected with platelet-rich plasma from young or old individuals.

RESULTS

In vitro experiments revealed that platelet-rich plasma from young donors induced a more youthful chondrocyte phenotype, as evidenced by increased type II collagen ( P = 0.033) and SOX-9 expression ( P = 0.022). This benefit, however, was significantly blunted when cells were cultured with platelet-rich plasma from aged donors. Accordingly, in vivo studies revealed that animals treated with platelet-rich plasma from young donors displayed a significantly improved cartilage integrity when compared with knees injected with platelet-rich plasma from aged donors ( P = 0.019).

CONCLUSIONS

Injection of platelet-rich plasma from a young individual induced a regenerative effect in aged cells and mice, whereas platelet-rich plasma from aged individuals showed no improvement in chondrocyte health or cartilage integrity.

A model-based quantitative analysis of efficacy and associated factors of platelet rich plasma treatment for osteoarthritis

OBJECTIVE

While platelet rich plasma (PRP) has been extensively studied in treating osteoarthritis (OA), there has been an ongoing debate regarding the efficacy of PRP and the optimal subpopulation for PRP treatment remains unknown. The authors hereby aim to establish a pharmacodynamic model-based meta-analysis to quantitatively evaluate PRP efficacy, comparing with hyaluronic acid (HA) and identify relevant factors that significantly affect the efficacy of PRP treatment for OA.

METHODS

The authors searched for PubMed and the Cochrane Library Central Register of Controlled Trials of PRP randomized controlled trials (RCTs) for the treatment of symptomatic or radiographic OA from the inception dates to 15 July 2022. Participants' clinical and demographic characteristics and efficacy data, defined as Western Ontario and McMaster Universities Osteoarthritis Index and visual analog scale pain scores at each time point were extracted.

RESULTS

A total of 45 RCTs (3829 participants) involving 1805 participants injected with PRP were included in the analysis. PRP reached a peak efficacy at ~ 2-3 months after injection in patients with OA. Both conventional meta-analysis and pharmacodynamic maximal effect models showed that PRP was significantly more effective than HA for joint pain and function impairment (additional decrease of 1.1, 0.5, 4.3, and 1.1 scores compared to HA treatment at 12 months for Western Ontario and McMaster Universities Osteoarthritis Index pain, stiffness, function, and visual analog scale pain scores, respectively). Higher baseline symptom scores, older age (≥60 years), higher BMI (≥30), lower Kellgren-Lawrence grade (≤2) and shorter OA duration (<6 months) were significantly associated with greater efficacy of PRP treatment.

CONCLUSION

These findings sugges t that PRP is a more effective treatment for OA than the more well-known HA treatment. The authors also determined the time when the PRP injection reaches peak efficacy and optimized the targeting subpopulation of OA. Further high-quality RCTs are required to confirm the optimal population of PRP in the treatment of OA.

Inflammaging and Osteoarthritis

Osteoarthritis is a highly prevalent disease particularly in subjects over 65 years of age worldwide. While in the past it was considered a mere consequence of cartilage degradation leading to anatomical and functional joint impairment, in recent decades, there has been a more dynamic view with the synovium, the cartilage, and the subchondral bone producing inflammatory mediators which ultimately lead to cartilage damage. Inflammaging is defined as a chronic, sterile, low-grade inflammation state driven by endogenous signals in the absence of infections, occurring with aging. This chronic status is linked to the production of reactive oxygen species and molecules involved in the development of age-related disease such as cancer, diabetes, and cardiovascular and neurodegenerative diseases. Inflammaging contributes to osteoarthritis development where both the innate and the adaptive immune response are involved. Elevated systemic and local inflammatory cytokines and senescent molecules promote cartilage degradation, and antigens derived from damaged joints further trigger inflammation through inflammasome activation. B and T lymphocyte populations also change with inflammaging and OA, with reduced regulatory functions, thus implicating self-reactivity as an additional mechanism of joint damage. The discovery of the underlying pathogenic pathways may help to identify potential therapeutic targets for the management or the prevention of osteoarthritis. We will provide a comprehensive evaluation of the current literature on the role of inflammaging in osteoarthritis and discuss the emerging therapeutic strategies.

Global research trends on platelet-rich plasma for tendon and ligament injuries from the past two decades: A bibliometric and visualized study

Background

In sports medicine, tendon and ligament injuries are the most prevalent conditions, and with the booming of sports competition, the incidence of sports injuries is gradually increasing, investigating more potent therapeutic options is therefore becoming increasingly crucial. Platelet-rich plasma therapy has gained popularity as an effective and secure treatment in recent years. Currently, a faceted systematic and clear visual analysis is lacking in this research area.

Methods

The literature related to using platelet-rich plasma to treat ligament and tendon injuries from 2003 to 2022 in the core dataset of the Web of Science database was collected and analyzed visually using Citespace 6.1 software. Research hotspots and development trends were analyzed in terms of high-impact countries or regions, authors, research institutions, keywords, and cited literature.

Results

The literature comprised a total of 1,827 articles. The annual publication volume of relevant literature has demonstrated a significant development tendency as the field of platelet-rich plasma research for tendon and ligament injuries has heated up in recent years. With 678 papers, the United States came in top place, followed by China with 187 papers. Hosp Special Surg ranked first with 56 papers. The hot research topics analyzed by keywords were tennis elbow, anterior cruciate ligament, rotator cuff repair, achilles tendon, mesenchymal stem cells, guided tissue regeneration, network meta analysis, chronic patellar tendinopathy, and follow up.

Conclusion

Analysis of the research literature over the past 20 years shows that the United States and China will continue to dominate in terms of volume of publications based on annual volume and trends, with some collaboration among high-impact authors and further collaboration still needed in different countries and institutions. Platelet-rich plasma is widely used in the treatment of tendon ligament injuries. Its clinical efficacy is influenced by a number of factors, the main ones being the inconsistency in the preparation and composition of platelet-rich plasma and its related preparations, and the differences in efficacy due to different activation methods of platelet-rich plasma, as well as factors such as injection time, injection site, administration method, number of administrations, acidity and evaluation methods, In addition, the applicability to different injury diseases remains controversial. In recent years, the molecular biology of platelet-rich plasma for tendon ligament therapy has received increasing attention.

Lateral Epicondylitis: Critical Analysis Review of Current Nonoperative Treatments

»

Lateral epicondylitis (LE) or tennis elbow is a common cause of elbow pain in the general population, especially women in the fourth and fifth decades of life who participate in repetitive forceful movements involving the wrist and forearm.

»

The pathogenesis of this overuse injury is believed to start from an overload event leading to a microtear in or near the origin of the extensor carpi radialis brevis that is subsequently prone to additional injury and structural weakness over time.

»

Treatment of LE often begins with a wide variety of nonoperative modalities including rest, nonsteroidal anti-inflammatory drugs, bracing, and physical therapy. For recalcitrant symptoms, additional nonoperative therapies are implemented; however, there remains a lack of comparative efficacy between these adjunct treatments.

»

In this article, we examine the available literature regarding nonoperative management of LE and provide supplementary insight into the effectiveness of current modalities.

The Epidemiology of Platelet-Rich Plasma Injections From 2010 to 2020 in a Large US Commercial Insurance Claims Database: A Recent Update

INTRODUCTION

The popularity of platelet-rich plasma (PRP) injections for the treatment of orthopaedic conditions has grown markedly. We sought to better define the trends in the usage of orthopaedic PRP injections across an insured US population over the past decade.

METHODS

The PearlDiver M91Ortho commercial administrative claims database was queried for all patients receiving PRP injections for orthopaedic conditions from 2010 through the first quarter of 2020 (Q1.2020). Trends in PRP use, reimbursement charges, demographics, joints injected, and administering physicians were assessed over time and reported as year-over-year (YOY) changes.

RESULTS

Over the study period, 14,096 unique patients had 17,759 orthopaedic PRP injections. The number of PRP injections administered had a YOY increase of 7.1% (144 injections/year, 95% confidence interval [CI] = 89 to 199, Ptrend = 0.0009). A YOY increase of 895% was observed in total nonsurgical charges ($683,974/yr, 95% CI 441,504 to 926,444, Ptrend = 0.0009). The median age of PRP recipients increased (YOY change = +0.6 years, 95% CI 0.4 to 0.8, Ptrend = 0.0005). Injections to the elbow (YOY change = -0.8%, 95% CI -0.10% to [-0.06%], Ptrend = 0.005) and foot/ankle (YOY change = -1.0%, 95% CI -1.4% to [-0.06%], Ptrend = 0.002) decreased, whereas hip (YOY change = +0.4%, 95% CI 0.2% to 0.6%, Ptrend = 0.019), knee (YOY change = +0.9%, 95% CI 0.3% to 1.2%, Ptrend = 0.016), and spine (YOY change = +0.2%, 95% CI 0.0% to 0.4%, Ptrend = 0.033) injections increased. PRP injections given by sports medicine orthopaedic surgeons (YOY change = +0.8%, 95% CI 0.6% to 1.2%, Ptrend <0.0001) increased over time, whereas those by general orthopaedic surgeons decreased (YOY change = -0.9, 95% CI -1.2 to [-0.6%], Ptrend = 0.001).

CONCLUSION

PRP injections quadrupled in prevalence from 2010 to Q1.2020, with a projected increase in annual usage in this data set of 66% by 2030. As greater evidence-based indications for PRP use are identified, more specialists and insurance providers may consider expanding their involvement in this growing field.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Hamstring Injuries: Critical Analysis Review of Current Nonoperative Treatments

➢

Hamstring injuries are common among active and athletic individuals, especially those involved in high-speed running, distance running, or sports requiring sudden directional changes. Acute hamstring strains often occur as an eccentric strain during running or a stretch-type injury caused by simultaneous hip flexion and knee extension. Proximal hamstring tendinopathy is an overuse injury of the hamstring tendon as a result of chronic cicatrization of the musculotendinous unit.

➢

Repeated stress to the hamstring tendon leads to increased cellularity of tendon fibers, disruption of collagen, and subsequent microinjury of the tissue that attaches the tendon to bone.

➢

Management of hamstring injuries generally begins with nonoperative modalities consisting of eccentric rehabilitative exercise programs. Although various other treatment modalities are available, the comparative efficacy of these supportive measures is not well differentiated at this time.

➢

In this article, we review the current literature with regard to the nonoperative treatment of hamstring injuries, specifically focusing on acute hamstring muscle strains and proximal hamstring tendinopathy in order to provide supplementary insight on the effectiveness of current modalities.

The levels of TGFβ1, VEGF, PDGF-BB, and PF4 in platelet-rich plasma of professional soccer players: a cross-sectional pilot study

Background

Regenerative therapy using platelet-rich plasma (PRP), a rich source of growth factors, has become popular in orthopedic sports medicine. Elite athletes prefer PRP therapy for their injured muscles and tendons primarily to avoid the possible risks of surgical treatment. However, the clinical effectiveness of PRP therapy in elite athletes compared to that in non-athletes remains unknown. Therefore, to investigate the effectiveness of PRP therapy in professional athletes (pro-athletes), we focused on the quality of PRP preparations and compared the levels of bioactive molecules between pro-athletes and non-athletes.

Methods

PRP was prepared from healthy, non-smoking male professional soccer players (pro-athletes) (n = 22) and non-athletes (VEGF: n = 34, others: n = 38). The levels of TGFβ1, PDGF-BB, VEGF, and PF4 were determined using ELISA kits. Polyphosphate was probed with 4’,6-diamidino-2-phenylindole and monitored using a fluorometer. The body composition of the donors was determined using a bathroom weighing scale.

Results

The levels of TGFβ1 and VEGF were significantly lower in pro-athletes than in non-athletes, whereas PF4 levels were significantly higher in pro-athletes. No significant difference was found in PDGF-BB levels between these groups. Biomolecule levels were not correlated with polyphosphate levels.

Conclusion

TGFβ1, VEGF, and PDGF-BB levels in pro-athletes were not higher than those in non-athletes. These findings suggest that growth factor levels in PRP may not be a predominant determinant of the clinical effectiveness of PRP therapy in pro-athletes. Increased PF4 levels in pro-athletes suggest an immunological function of PRP that may positively influence tissue regeneration.

Gene therapy approaches for equine osteoarthritis

With an intrinsically low ability for self-repair, articular cartilage injuries often progress to cartilage loss and joint degeneration resulting in osteoarthritis (OA). Osteoarthritis and the associated articular cartilage changes can be debilitating, resulting in lameness and functional disability both in human and equine patients. While articular cartilage damage plays a central role in the pathogenesis of OA, the contribution of other joint tissues to the pathogenesis of OA has increasingly been recognized thus prompting a whole organ approach for therapeutic strategies. Gene therapy methods have generated significant interest in OA therapy in recent years. These utilize viral or non-viral vectors to deliver therapeutic molecules directly into the joint space with the goal of reprogramming the cells' machinery to secrete high levels of the target protein at the site of injection. Several viral vector-based approaches have demonstrated successful gene transfer with persistent therapeutic levels of transgene expression in the equine joint. As an experimental model, horses represent the pathology of human OA more accurately compared to other animal models. The anatomical and biomechanical similarities between equine and human joints also allow for the use of similar imaging and diagnostic methods as used in humans. In addition, horses experience naturally occurring OA and undergo similar therapies as human patients and, therefore, are a clinically relevant patient population. Thus, further studies utilizing this equine model would not only help advance the field of human OA therapy but also benefit the clinical equine patients with naturally occurring joint disease. In this review, we discuss the advancements in gene therapeutic approaches for the treatment of OA with the horse as a relevant patient population as well as an effective and commonly utilized species as a translational model.

Study protocol for double-blind, randomised placebo-controlled trial evaluating semitendinosus function and morbidity following tendon harvesting for anterior cruciate ligament reconstruction augmented by platelet-rich plasma

INTRODUCTION

Anterior cruciate ligament (ACL) rupture is debilitating, often requiring surgical reconstruction. An ACL reconstruction (ACLR) using a tendon autograft harvested from the semitendinosus results in substantial injury to the donor muscle. Following ACLR, patients rarely return to their preinjury level of physical activity, are at elevated risk of secondary lower limb injuries and early onset knee osteoarthritis. To date, no randomised controlled trial has evaluated the efficacy of platelet-rich plasma (PRP) in aiding knee function and semitendinosus morphology of following ALCR.

METHODS AND ANALYSIS

This is a multicentre double-blind randomised placebo-controlled trial. Fifty-four ACLR patients aged 18-50 years will be randomised to receive either a single application of PRP (ACLR+) or placebo saline (ACLR) into the semitendinosus harvest zone at the time of surgery. All patients will undergo normal postoperative rehabilitation recommended by the attending orthopaedic surgeon or physiotherapist. The primary outcome measure is between-limb difference (ACLR compared with intact contralateral) in isometric knee flexor strength at 60^o knee flexion, collected 10-12 months postsurgery. This primary outcome measure will be statistically compared between groups (ACLR+ and standard ACLR). Secondary outcome measures include bilateral assessments of hamstring muscle morphology via MRI, biomechanical and electromyographic parameters during an anticipated 45° running side-step cut and multidirectional hopping task and patient-reported outcomes questionaries. Additionally, patient-reported outcomes questionaries will be collected before (baseline) as well as immediately after surgery, and at 2-6 weeks, 3-4 months, 10-12 months and 22-24 months postsurgery 10-12 months following surgery.

ETHICS AND DISSEMINATION

Ethics approval has been granted by Griffith University Human Research Ethics Committee, Greenslopes Research and Ethics Committee, and Royal Brisbane & Women's Hospital Human Research Ethics Committee. Results will be submitted for publication in a peer-reviewed medical journal.

TRIAL REGISTRATION NUMBER

ACTRN12618000762257p.

Current Trends in Orthobiologics: An 11-Year Review of the Orthopaedic Literature

BACKGROUND

The use of "orthobiologics" or regenerative therapies in orthopaedic surgery has grown in recent years. Particular interest has been raised with regard to platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cells. Although studies have analyzed outcomes after orthobiologic treatment, no study has analyzed how the literature as a whole has evolved.

PURPOSE

To evaluate trends in platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cell publications and to assess how these might inform efforts to establish minimum reporting standards and forecast future use.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A database was compiled systematically using PubMed to identify articles published between 2009 and 2019 within 9 prominent orthopaedic journals and pertaining to the use of platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cells in the treatment of musculoskeletal conditions. Included articles were classified as clinical, nonclinical (translational or basic science), or review, and a variety of study parameters were recorded for each. Additional queries were performed to identify articles that utilized minimum reporting standards.

RESULTS

A total of 474 articles (132 clinical, 271 nonclinical, 71 review) were included, consisting of 244 (51.5%) platelet-rich plasma, 146 (30.8%) bone marrow aspirate, 72 (15.2%) adipose-derived cells, and 12 (2.5%) amniotic cells. The greatest annual increase in publications for each orthobiologic topic was from 2018 to 2019. The American Journal of Sports Medicine demonstrated the highest number of overall (34.2%) and clinical (50.0%) publications, and accounted for 44.3% of all platelet-rich plasma publications. The Journal of Orthopaedic Research accounted for the second highest overall number of publications (24.9%) and highest nonclinical publications (41.0%). Platelet-rich plasma accounted for 91.5% of all level 1 clinical studies, while much greater than half of bone marrow aspirate, adipose-derived cells, and amniotic cell publications were level 3 or lower. Out of the 207 articles that used some form of reporting protocol, 59 (28.5%) used an established algorithm and 125 (60.4%) used their own.

CONCLUSION

Interest in orthobiologics continues to grow, as evidenced by an increasing trend in publications over an 11-year period. However, current reporting on orthobiologic formulations is largely heterogeneous, emphasizing the need for minimum reporting standards and higher-quality studies.

A systematic review on the efficacy of different types of platelet-rich plasma in the management of lateral epicondylitis

BACKGROUND

Platelet-rich plasma (PRP) is reported as an effective treatment for lateral epicondylitis (LE). Theoretically, different types of PRP have different therapeutic effects. However, there is controversy on the effects of different types of PRP in the treatment of LE. The purpose of this study was to systematically compare pain relief, functional improvement, and the success rate of treatment using 2 different types of PRP by reviewing and summarizing the data available in the current literature on LE after PRP injection.

METHODS

The PubMed, MEDLINE, Embase, Cochrane Library, and Web of Science databases were reviewed. A computerized literature search was performed for related studies published from database inception to August 2021 using the following terms: lateral epicondylitis, tennis elbow, tendinopathy, lateral elbow pain, PRP, and platelet-rich plasma. The PRP patients included in our study were divided into those receiving leukocyte-poor PRP (LP-PRP) and those receiving leukocyte-rich PRP (LR-PRP) according to the different preparation methods. Outcomes of interest included patient characteristics, types and preparations of PRP, clinical outcomes, success rates, and the safety of treatment at short- and long-term follow-up.

RESULTS

A total of 33 studies were evaluated in our analysis, including 2420 LE patients. LP-PRP was used in 19 of these studies, LR-PRP was used in 13, and both LP-PRP and LR-PRP were used in 1. Patients in both PRP groups showed significantly improved clinical outcomes after treatment compared with before treatment. The mean visual analog scale scores ranged from 6.1 to 8.0 before treatment, ranged from 1.5 to 4.0 at short-term follow-up, and ranged from 0.6 to 3.3 at long-term follow-up in the LR-PRP group. The mean visual analog scale scores ranged from 4.2 to 8.4 before treatment, 1.6 to 5.9 at short-term follow-up, and 0.7 to 2.7 at long-term follow-up in the LP-PRP group. The Disabilities of the Arm, Shoulder and Hand scores in the LR-PRP and LP-PRP groups ranged from 47.0 to 54.3 and 30.0 to 67.7, respectively, before treatment and ranged from 20.0 to 22.0 and 5.5 to 19.0, respectively, at long-term follow-up. The success rates in the LR-PRP and LP-PRP groups ranged from 70% to 100% and 36% to 100%, respectively. The complication rate was lower in the LP-PRP group (3.9%) than in the LR-PRP group (6.4%, P = .029), with the main complication being temporary pain after PRP treatment.

CONCLUSION

PRP treatment demonstrated significant improvements in terms of pain relief and functional improvement in LE patients regardless of the type of PRP. There were no significant differences in pain relief and functional improvement between LR-PRP and LP-PRP. The main complication was temporary pain after PRP injection, and the complication rate in the LP-PRP group was lower than that in the LR-PRP group.

Efficacy of a Novel Intra-Articular Administration of Platelet-Rich Plasma One-Week Prior to Hyaluronic Acid versus Platelet-Rich Plasma Alone in Knee Osteoarthritis: A Prospective, Randomized, Double-Blind, Controlled Trial

Recent studies have suggested that the combined injection of platelet-rich plasma (PRP) and hyaluronic acid (HA) may have additive benefits for knee osteoarthritis over PRP alone, but there is insufficient evidence to support this combined injection. Moreover, the simultaneous injection of PRP and HA may offset the combined effect. Hence, the aim of this prospective, randomized, double-blind study was to assess their combined efficacy with a novel injection protocol. Forty-six study subjects with unilateral knee osteoarthritis were randomized to receive either a single-dose injection of HA (intervention group) or normal saline (control group) 1 week after a single-dose injection of leukocyte-poor PRP. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and static balance and the risk of falls measured by Biodex Balance System were, respectively, the primary and secondary outcome measures. Evaluations were performed at baseline, 1 month, 3 months, 6 months, and 12 months post-injection. The intervention group exhibited significant declines in WOMAC pain, stiffness, and total scores, as well as static balance, compared to the control group (p < 0.05). These randomized double-blind control trials, with novel protocol of intra-articular injection of PRP 1-week prior to HA, provide greater symptom relief and improve static balance compared to PRP alone in patients with knee osteoarthritis.

Platelet-rich plasma inhibits inflammation, apoptosis, and the NLRP3/Caspase-1 pathway and induces matrix metalloproteinases and proliferation of IL-1β-induced articular chondrocytes by downregulating T-box transcription factor 3

Objectives

Osteoarthritis (OA) is a chronic joint disease characterized by osteoproliferation and the degeneration and destruction of articular cartilage. Platelet-rich plasma (PRP) is rich in various growth factors that have been reported to promote bone defect repair. This study examined the specific role and mechanism of PRP in OA.

Methods

OA model cells were created by treating articular chondrocytes with IL-1β. After treatment of the model cells with PRP or/and a T-box transcription factor 3 (TBX3)-overexpression plasmid, TBX3 expression was monitored via RT-qPCR, western blotting, and immunofluorescence assays. IL-1β, IL-33, and Caspase-3 levels were detected with ELISA kits. Levels of NLRP3, Caspase-1, MMP9, MMP13, and COL2A1 expression were evaluated by western blotting, and cell proliferation was assessed by the CCK-8 assay.

Results

Our results showed that TBX3 expression was upregulated in IL-1β-induced articular chondrocytes. IL-1β stimulation induced inflammation and the production of matrix metalloproteinases, activated Caspase-3 and the NLRP3/Caspase-1 pathway, inhibited the proliferation of articular chondrocytes; however, all those affects mediated by IL-1β could be markedly reversed by PRP. We also found that PRP alleviated IL-1β-induced inflammation, apoptosis, and extracellular matrix degradation in articular chondrocytes by inhibiting TBX3. Our findings suggest that PRP alleviates OA progression in vitro by downregulating TBX3.

Conclusion

PRP suppressed OA progression in vitro by inhibiting TBX3, which may be its mechanism of action in treating OA.

Cortical allograft strut augmented with platelet-rich plasma for the treatment of long bone non-union in lower limb- a pilot study

Background

The autogenous iliac bone graft is the first choice of surgical treatment for long bone non-union. However, many factors limit the use of autogenous bone, such as insufficient bone harvest and complications in the donor site. This study aimed to pilot-test the effectiveness of the cortical allograft strut augmented with Platelet-rich plasma (PRP) on long bone non-union in the lower limb.

Method

This study was a one-armed pilot trial, with thirteen men and four women patients scheduled for surgery. Revision surgery for managing long bone non-union included debridement, internal fixation of the cortical allograft strut, and adding PRP in the fracture site. After surgery, outcome measurements of healing rate, healing time, the incidence of revision, and complications, were assessed at least one-year follow-up.

Results

Fourteen of seventeen participants completed all follow-ups. The mean age of 14 patients was 35.9 years (range, 18–56 years), and the mean BMI was 22.44 ± 1.53 kg/m². All nonunions united after the operation. The mean healing time was 4.6 ± 0.7 months. There was no revision or complication.

Conclusion

Cortical allograft strut augmented with PRP led to healing long bone non-union in the lower limb. More clinical research is required before widespread use.

Assessment of Characteristics and Methodological Quality of the Top 50 Most Cited Articles on Platelet-Rich Plasma in Musculoskeletal Medicine

Background:

The wide range of clinical applications and controversial scientific evidence associated with platelet-rich plasma (PRP) therapy in musculoskeletal medicine requires an examination of the most commonly cited studies within this field.

Purpose:

To identify the 50 most cited articles on PRP, assess their study design, and determine any correlations between the number of citations and level of evidence (LoE) or methodological quality.

Study Design:

Cross-sectional study.

Methods:

The Web of Science database was queried to identify the top 50 most cited articles on PRP in orthopaedic surgery. Bibliometric characteristics, number of citations, and LoE were recorded. Methodological quality was evaluated using the Modified Coleman Methodology Score (MCMS), Methodological Index for Non-randomized Studies (MINORS), and Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO). The Pearson correlation coefficient and Spearman correlation coefficient (r_S) were used to determine the degree of correlation between the number of citations or citation density and LoE, MCMS, MINORS score, and MIBO score. Student t tests were performed for 2-group comparisons.

Results:

The top 50 articles were published between 2005 and 2016 in 21 journals. The mean number of citations and citation density were 241 ± 94 (range, 151-625) and 23 ± 8, respectively, and the mean LoE was 2.44 ± 1.67, with 15 studies classified as LoE 1. The mean MCMS, MINORS score, and MIBO score were 66.9 ± 12.6, 16 ± 4.7, and 12.4 ± 3.7, respectively. No correlation was observed between the number of citations or citation density and LoE, MCMS, MINORS score, and MIBO score. A significant difference (P = .02) was noted in LoE in articles from the United States (3.56 ± 1.7) versus outside the United States (2 ± 1.5). Seven of the 8 in vivo studies were published between 2005 and 2010, whereas 19 of the 25 clinical outcome investigations were published between 2011 and 2016. Studies that were published more recently were found to significantly correlate with number of citations (r_S = –0.38; P = .01), citation density (r_S = 0.36; P = .01), and higher LoE (r_S = 0.47; P = .01).

Conclusion:

The top 50 most cited articles on PRP consisted of high LoE and fair methodological quality. There was a temporal shift in research from in vivo animal studies toward investigations focused on clinical outcomes.

VEGF-attenuated platelet-rich plasma improves therapeutic effect on cartilage repair

Autologous platelet-rich plasma (PRP) has gained popularity as a less invasive treatment for various musculoskeletal tissue injuries and conditions due to its favorable safety profile, minimal manipulation and cost-effectiveness. Although PRP treatment has been clinically used for the treatment of osteoarthritis (OA) and damaged cartilage, evidence on therapeutic efficacy has been inconsistent, which calls for a methodology to achieve consistent and improved treatment outcomes. Given that PRP contains numerous proteins, we hypothesized that attenuation of a growth factor known to be detrimental to the healing tissue would enhance efficacy of PRP treatment. Considering that VEGF-mediated angiogenesis inhibits the repair of articular cartilage, we developed VEGF-attenuated PRP by sequestering VEGF in PRP using VEGF-binding microspheres. We demonstrated that VEGF attenuation in PRP did not inhibit the effect of PRP on chondrogenic differentiation of stem cells in vitro. In addition, healing of rat OA cartilage was significantly improved after treatment with VEGF-attenuated PRP when compared to the PRP treatment group or PBS control group. We expect that attenuation of unwanted biological activity using growth factor-binding microspheres could provide a new PRP customization method broadly applicable to various tissue repair processes.

Isolation of Platelet-Derived Exosomes from Human Platelet-Rich Plasma: Biochemical and Morphological Characterization

Platelet-Rich Plasma (PRP) is enriched in molecular messengers with restorative effects on altered tissue environments. Upon activation, platelets release a plethora of growth factors and cytokines, either in free form or encapsulated in exosomes, which have been proven to promote tissue repair and regeneration. Translational research on the potential of exosomes as a safe nanosystem for therapeutic cargo delivery requires standardizing exosome isolation methods along with their molecular and morphological characterization. With this aim, we isolated and characterized the exosomes released by human PRP platelets. Western blot analysis revealed that CaCl₂-activated platelets (PLT-Exos-Ca²⁺) released more exosomes than non-activated ones (PLT-Exos). Moreover, PLT-Exos-Ca²⁺ exhibited a molecular signature that meets the most up-to-date biochemical criteria for platelet-derived exosomes and possessed morphological features typical of exosomes as assessed by transmission electron microscopy. Array analysis of 105 analytes including growth factors and cytokines showed that PLT-Exos-Ca²⁺ exhibited lower levels of most analytes compared to PLT-Exos, but relatively higher levels of those consistently validated as components of the protein cargo of platelet exosomes. In summary, the present study provides new insights into the molecular composition of human platelet-derived exosomes and validates a method for isolating highly pure platelet exosomes as a basis for future preclinical studies in regenerative medicine and drug delivery.

Minimally Invasive Successful Reconstruction of a Severely Traumatized Upper Extremity Using Platelet-Rich Plasma and Tissue Scaffold: A Case Report

Minimally invasive reconstruction combines principles of tissue engineering and regenerative medicine for healing complex wounds. This approach was successfully demonstrated on a 64-year-old diabetic and hypertensive male patient, who was brought unconscious to our emergency after surviving an automobile collision with severe brain and right-dominant upper extremity injuries. Uncontrolled hyperglycemia, severe anemia, diffuse axonal brain injury, wrist drop, and loss of thumb extension and abduction were noted. Extensive degloving, skin necrosis, extensor and flexor forearm muscle crush injuries, and ruptured extensor tendons were observed. Serial wound debridement combined with platelet-poor plasma injection into the muscles, platelet-rich plasma injections into the tendons and subcutis, and low-negative pressure wound therapy were performed sequentially to salvage the injured soft-tissues. Improvements were noticed during the second exploration after 5 days. Surviving muscles showed adequate vascularization and revival of innervation during the third exploration after another 5 days. Thereafter, absorbable synthetic tissue scaffold was applied over a sizeable 270 cm ² wound as a flap-alternative. Tissues regenerated well within the scaffold during the next 2 months, halving the wound area to 132 cm ² . A thick split-skin graft was applied over the remaining granulating neodermis, which “took” completely. Six months postoperatively, the patient regained most hand functions and performed all activities satisfactorily, while the grafted area appeared almost identical to surroundings. Minimally invasive reconstruction thus produced satisfying results with fewer shorter simpler surgeries, minimal anesthesia, short-duration hospitalization, lower health care costs, lesser risks, and excellent patient-reported outcomes.

Applications of the regenerative capacity of platelets in modern medicine

Platelets produce platelet growth factors such as PDGF, IGF-1, EGF-, HGF, TGFβ, bFGF, and VEGF, which are crucial in regulating all stages of the wound healing process. The source of these substances is platelet-rich plasma (PRP). Over the past five decades, the interest and use of the regenerative properties of platelets have increased significantly in many different fields of medicine around the world. PRP and PRF plate preparations are used in: 1. Dentistry (they reduce bleeding, facilitate and accelerate soft tissue healing and bone regeneration - FGF 2, IGF-1, IGF-2, TGF-β1, and PDGF); 2. Sports medicine - IGF-1, IGF-2, TGF-β, VEGF, PDGF and bFGF, EGF); 3. dermatology and cosmetology (treatment of alopecia, hair reconstruction - FGF-7, HGF, acne scars, skin rejuvenation and regeneration, treatment of chronic and poorly healing wounds, burns, and acquired vitiligo); 4. Gynecology and reproductive medicine (treatment of infertility, erectile dysfunction - PDGF-β, TGF-β, IGF-1, in sexual dysfunction - PDGF, in vaginal atrophy); 5 Ophthalmology (in the healing of corneal epithelial wounds, in the treatment of dormant corneal ulcers, dry eye syndrome and the reconstruction of the corneal surface; 6. Neurology (regeneration of neurons, pain alleviation, and clinical symptoms - TGF-β 1, IGF-1, PDGF, VEGF) and FGF). Platelet-rich plasma therapy is a very interesting alternative and complement to traditional methods of treatment. However, the potential for using platelets is still not fully understood. The composition of platelet-rich plasma depends on many factors that may affect its use's efficacy and clinical benefits. Further research is necessary to standardize PRP delivery's preparation procedures and methods for a specific disease entity or clinical case.

Comparison of a Platelet-Rich Plasma Injection and a Conventional Steroid Injection for Pain Relief and Functional Improvement of Partial Supraspinatus Tears

Background

Partial supraspinatus tendon tears have frequently been treated using a subacromial corticosteroid injection or surgery. The clinical use of a platelet-rich plasma (PRP) injection is an alternative treatment method for the condition, despite the paucity of evidence of its efficacy.

Purpose

To compare pain relief, functional improvement, and complications after an intratendinous PRP injection versus a subacromial corticosteroid injection for partial supraspinatus tears.

Study Design

Randomized controlled trial; Level of evidence, 1.

Methods

A total of 32 patients with partial supraspinatus tears were randomly assigned to receive a leukocyte-poor PRP (LP-PRP) injection or a corticosteroid injection. One patient withdrew from the PRP group, leaving 15 patients in the PRP group and 16 patients in the corticosteroid group. The ultrasound-guided procedures were performed by a single experienced pain physician. Pain relief and functional improvement were evaluated using the visual analog scale (VAS) and the Oxford Shoulder Score (OSS), respectively. Treatment efficacy and complications were documented, and the 2 groups were compared at 1- and 6-month follow-up.

Results

There were no differences in VAS and OSS scores between the PRP and corticosteroid groups at 1-month follow-up. However, the PRP group had better scores than the corticosteroid group had on both the VAS and OSS at 6-month follow-up (VAS: 14.5 ± 15.4 vs 37.5 ± 24.9, respectively; OSS: 16.2 ± 3.9 vs 25.0 ± 10.2, respectively; P < .01 for both). Both groups showed significant improvement in VAS and OSS scores from before treatment to 1-month follow-up (mean difference, 35.67 and 11.47 points, respectively, for the PRP group; mean difference, 29.69 and 11.13 points, respectively, for the corticosteroid group; P < .01 for all). The VAS and OSS scores did not change significantly at 6-month follow-up in the corticosteroid group; however, the PRP group showed continued improvement in both VAS and OSS scores between 1- and 6-month follow-up (mean difference, 15.87 and 7.40 points, respectively; P < .01 for both). There were no complications in either group.

Conclusion

An injection using either a corticosteroid or LP-PRP resulted in a similar reduction in pain and improvement in function at 1 month in patients with a partial supraspinatus tear. However, PRP showed superior benefits over the corticosteroid at 6-month follow-up.

The Efficacy of Platelet-Rich Plasma for Improving Pain and Function in Lateral Epicondylitis: A Systematic Review and Meta-analysis with Risk-of-Bias Assessment

PURPOSE

To assess the efficacy of platelet-rich plasma (PRP) for lateral epicondylitis and evaluate its impact on pain and functional outcomes.

METHODS

This study followed Preferred Reporting Items and Systematic Reviews and Meta-Analyses guidelines. A comprehensive literature search was conducted in September 2019 and repeated in April 2020 using electronic databases PubMed, MEDLINE, and the Cochrane Library. Baseline and 3-, 6-, and 12-month data were extracted for visual analog scale (VAS), Disabilities of the Arm, Shoulder, and Hand (DASH), and modified Mayo Clinic performance index for the elbow (MAYO) scores. Only level 1 studies with patients who had not undergone surgery were included. Outcomes data, study design, demographic variables, PRP formulation, and comparator treatments were recorded. Statistical analyses of pooled weighted mean differences (WMDs) were performed and compared with estimated minimal clinically important difference (MCID) values. The Coleman Methodology Score (CMS) was used to assess methodological quality, and the Cochrane risk-of-bias assessment was performed.

RESULTS

This review included 16 level I studies, 9 of which (581 total patients, 281 receiving single injections of PRP) were quantitatively analyzed. The average age was 41.5 years, 56.8% of patients were female, and mean follow-up was 7.5 months. The mean CMS was 78.94 ± 12.74 (range 59 to 97), and 5 of 16 studies were at low risk for bias. Patients who received PRP had significantly improved VAS scores at 3 months (WMD -0.85; 95% confidence interval [CI] -1.03, -0.66; P < .01) and 6 months (WMD -0.74; 95% CI -0.98, -0.50; P < .01) compared with those who received autologous whole blood, though MAYO scores were statistically equivalent. Comparing PRP to corticosteroids, VAS and DASH scores were not significantly different at 3 months, although PRP was superior at 6 months for VAS (WMD -1.70; 95% CI -2.65, -0.75; P < .01) and DASH (WMD -6.23; 95% CI -10.78, -1.69; P < .01). Most differences in VAS and DASH scores exceeded the 5% absolute difference estimate for their respective MCIDs but fell short of the 10% estimate.

CONCLUSION

Considering the small number of comparable studies, lack of quantification of specific PRP content, considerable heterogeneity between randomized control trials, and most effect sizes being equivocal within the framework of 2 estimated MCID values, the authors can neither scientifically support nor discourage the usage of PRP for lateral epicondylitis despite finding statistically significant improvements in pain and functional outcomes.

LEVEL OF EVIDENCE

I, prognostic.

Does PRGF Work? A Prospective Clinical Study in Dogs with A Novel Polylactic Acid Scaffold Injected with PRGF Using the Modified Maquet Technique

Simple Summary

PRGF is a concentration of autologous platelets in a small volume of plasma, which is performed in a specific way and is an accessible resource in veterinary medicine. The PRGF has multiple demonstrated properties as antimicrobial, analgesic and anti-inflammatory but their osteoinductivity potential is controversial. We decided to use PRGF in combination with a PLA bioresorbable scaffold (a specific type of implant with osteoconduction properties) performed by 3D printing, and personalized for each patient, to determinate if the PRGF can produce osteoinduction and as a result, a faster bone healing and a faster patient recovery. Furthermore, in this study PLA scaffolds are proposed as an alternative for metallic implants to avoid the problems that those can cause. The MMT was the technique selected for solving the RCrCL as it is a variant of TTA that follows the same principle for the correction of the patellar tendon angle to neutralize distractive forces; however, this technique needs a lower amount of metallic implants for the scaffold fixation.

Abstract

Tibial tuberosity advancement is a surgical technique to restore the dynamical stability in the knee by advancing the insertion of the patellar ligament, for which it is necessary to advance the tibial crest, being maintained in the desired position usually by a cage and metallic implants. The purpose of this study was to replace the cage with a polylactic acid biodegradable scaffold designed for each patient by 3D printing, inserting platelet-rich in growth factors (PRGF) to demonstrate its osteoinductive properties. To this end, we used the modified Maquet technique to reduce the amount of metal to a minimum. Fifty-three dogs finished the study. The control and PRGF groups did not present any statistically significant differences in terms of ossification degree (p > 0.001) but they demonstrated satisfactory ossification compared to previous publications, although in the PRGF group three of the scaffolds suffered complete reabsorption. The PRGF and control groups did not show any statistically significant differences in terms of lameness degree (p > 0.001). However, the PRGF group showed at the first control some analgesic and anti-inflammatory properties but they were not enough for reducing the functional recovery time in a significant way. The PRGF group did not show any complications or negative results associated with their use.

Double-Row Rotator Cuff Repair Enhanced With Platelet-Rich Therapy Reduces Retear Rate: A Systematic Review and Meta-analysis of Randomized Controlled Trials

PURPOSE

To assess retear rates in arthroscopic double-row rotator cuff repair (double-row RCR) with and without platelet-rich therapy (PRT).

METHODS

Systematic review and meta-analysis of randomized controlled trials (RCTs). MEDLINE, Embase, and Scopus databases were searched for RCTs involving use of PRT exclusively in arthroscopic double-row RCR. A random-effects model and the generic inverse variance method were used for quantitative data synthesis. Heterogeneity was tested with the I² statistic index.

RESULTS

The 9 RCTs included in the meta-analysis demonstrated a risk reduction of 49% for retears in patients receiving PRT (risk ratio [RR] 0.51; 95% confidence interval [CI] 0.35 to 0.76; P = .0008; I² = 0%). Divided by tear sizes, retear risk reduction of 47% (RR 0.53; 95% CI 0.30 to 0.95; P = .03; I² = 0%) was found in small to medium tears and 51% (RR 0.49; 95% CI 0.29 to 0.84; P = .009; I² = 0%) in large to massive tears. Linked double-row RCR resulted in risk reduction of 51% for retears in comparison with nonlinked repairs.

CONCLUSION

Double-row RCR plus PRT significantly reduced retear rates in all sizes of rotator cuff tears. Linked double-row RCR and applying the PRT during the surgical procedure and in the tendon-bone interface reproduced the best outcomes. Clinically, all patients improved, and no statistically significant difference was seen in clinical and functional scores between the intervention groups. All patients achieved optimal values for patient-reported outcomes measures.

LEVEL OF EVIDENCE

I, systematic review and meta-analysis of level I studies.

Percutaneous injection of platelet-rich plasma to treat atrophic nonunion after internal fixation of ulnar fracture: a case report

Non-union is a serious postoperative complication of fracture. Early detection and intervention can avoid revision surgery. Platelet-rich plasma releases many active tissue factors and has potential to promote fracture healing. Percutaneous injection of platelet-rich plasma at the fracture site may avoid surgical treatment when non-union occurs. We present a case of atrophic non-union of an ulna fracture treated conservatively with percutaneous injection of platelet-rich plasma.

Peripheral Nerve Regeneration Using a Cytokine Cocktail Secreted by Skeletal Muscle-Derived Stem Cells in a Mouse Model

Severe peripheral nerve injury, which does not promise natural healing, inevitably requires clinical treatment. Here, we demonstrated the facilitation effect of peripheral nerve regeneration using a cytokine cocktail secreted by skeletal muscle-derived stem cells (Sk-MSCs). Mouse sciatic nerve was transected with a 6 mm gap and bridged collagen tube, and the culture supernatant of Sk-MSCs with 20% adult mouse serum (AMS)/Iscove’s modified Dulbecco’s medium (IMDM) was administered into the tube immediately after the operation, followed by an injection once a week for six weeks through the skin to the surrounding tube of the cytokine (CT) group. Similarly, 20% AMS/IMDM without cytokines was administered to the non-cytokine control (NT) group. Tension recovery in the plantar flexor muscles via electrical stimulation at the upper portion of the damaged nerve site, as well as the numerical recovery of axons and myelinated fibers at the damaged site, were evaluated as an index of nerve regeneration. Specific cytokines secreted by Sk-MSCs were compared with damaged sciatic nerve-derived cytokines. Six weeks after operation, significantly higher tension output and numerical recovery of the axon and myelinated fibers were consistently observed in the CT group, showing that the present cytokine cocktail may be a useful nerve regeneration acceleration agent. We also determined 17 candidate factors, which are likely included in the cocktail.

Effects of Platelet-Rich Plasma on Cellular Populations of the Central Nervous System: The Influence of Donor Age

Platelet-rich plasma (PRP) is a biologic therapy that promotes healing responses across multiple medical fields, including the central nervous system (CNS). The efficacy of this therapy depends on several factors such as the donor's health status and age. This work aims to prove the effect of PRP on cellular models of the CNS, considering the differences between PRP from young and elderly donors. Two different PRP pools were prepared from donors 65‒85 and 20‒25 years old. The cellular and molecular composition of both PRPs were analyzed. Subsequently, the cellular response was evaluated in CNS in vitro models, studying proliferation, neurogenesis, synaptogenesis, and inflammation. While no differences in the cellular composition of PRPs were found, the molecular composition of the Young PRP showed lower levels of inflammatory molecules such as CCL-11, as well as the presence of other factors not found in Aged PRP (GDF-11). Although both PRPs had effects in terms of reducing neural progenitor cell apoptosis, stabilizing neuronal synapses, and decreasing inflammation in the microglia, the effect of the Young PRP was more pronounced. In conclusion, the molecular composition of the PRP, conditioned by the age of the donors, affects the magnitude of the biological response.

Cell-free Stem Cell-Derived Extract Formulation for Regenerative Medicine Applications

Stem cells for regenerative medicine purposes offer therapeutic benefits, but disadvantages are still ill defined. The benefit of stem cells may be attributed to their secretion of growth factors (GFs), cytokines (CKs), and extracellular vesicles (EVs), including exosomes. We present a novel cell-free stem cell-derived extract (CCM), formulated from human progenitor endothelial stem cells (hPESCs), characterized for biologically active factors using ELISA, nanoparticle tracking analysis and single particle interferometric reflectance imaging sensing. The effect on fibroblast proliferation and ability to induce stem cell migration was analyzed using Alamar Blue proliferation and Transwell migration assays, respectively. GFs including IGFBP 1, 2, 3, and 6, insulin, growth hormone, PDGF-AA, TGF-α, TGF-β1, VEGF, and the anti-inflammatory cytokine, IL-1RA were detected. Membrane enclosed particles within exosome size range and expressing exosome tetraspanins CD81 and CD9 were identified. CCM significantly increased cell proliferation and induced stem cell migration. Analysis of CCM revealed presence of GFs, CKs, and EVs, including exosomes. The presence of multiple factors including exosomes within one formulation, the ability to promote cell proliferation and induce stem cell migration may reduce inflammation and pain, and augment tissue repair.

Distribution and quantification of activated platelets in platelet-rich fibrin matrices

Platelet-rich fibrin (PRF) has been widely applied in regenerative therapy owing to its simple preparation protocol. To date, the original protocol for preparing leukocyte-rich (L)-PRF has been modified to produce derivatives such as advanced (A)-PRF, concentrated growth factors (CGF), and horizontal (H)-PRF. However, these derivatives have not been rigorously compared to explore possible differences. We previously developed and validated a nondestructive near-infrared (NIR) imaging method to quantitatively examine the platelet distribution in PRF matrices. To further evaluate the characteristics of platelets in PRF, we herein examined the distribution of activated platelets. Four types of PRF matrices were prepared under different centrifugal conditions from blood samples obtained from the same healthy donors. After fixation and compression, the matrices were stained immunohistochemically without sectioning and visualized using an NIR imager. Qualitative morphological analysis revealed that whole platelets were distributed widely and homogeneously in H-PRF and A-PRF, but localized along the distal tube surface in L-PRF and CGF. Activated platelets were distributed as were whole platelets in A-PRF, L-PRF, and CGF, but localized mainly in the "buffy coat" region in H-PRF. Quantitative analysis revealed that there was no significant difference in the ratio of activated to whole platelets between PRF derivatives. These findings suggest that platelet activation is similarly induced in fibrin matrices regardless of centrifugal speed or rotor angulation. However, only the H-PRF group was distinguishable from the other PRF derivatives in terms of activated platelet distribution.

Maxillary sinus lift response to platelet-rich plasma associated with autogenous bone, ceramic biphasic HA/β-TCP (70:30), or deproteinized bovine bone

BACKGROUND

This study evaluated the long-term effects of platelet-rich plasma (PRP) on bone formation and regeneration when associated with autogenous bone graft (AB), porous biphasic calcium phosphate (pBCP), or deproteinized bovine bone (DBB) in maxillary sinus augmentation (MSA) of rabbit.

METHODS

In 54 rabbits, bilateral MSA procedure was performed and randomly one sinus was filled with 200 mm³ material plus blood clot (AB/clot, DBB/clot, and pBCP/clot) and other with the same graft plus PRP (AB/PRP, DBB/PRP, and pBCP/PRP). After 30, 60, and 180 days, microtomographic were performed to analyze the three-dimensional MSA volume and histomorphometric analyses for the percentage of bone and soft tissues ingrowth. Data were compared by two-way ANOVA and the means were compared by the Tukey test, at p < 0.05.

RESULTS

The percentage of pBCP and DBB were nearly unchanged throughout the whole period and bone formation occurred in the spaces between particles. The MSA volume filled with DBB and pBCP agglutinated with clot and PRP maintained constant during all experimental periods (147.2 mm³ and 154.9 mm³, respectively, p = 0.7377), and no significant changes in the new formatted bone and soft tissue were observed between treatments. In AB/clot and AB/PRP, the MSA volume was similar at 30 days (140.3 mm³ and 137.9 mm³, respectively), but a higher and gradual reduction was observed until 180 days. In the AB/PRP, this reduction was significantly higher (44.2%) than AB/clot (22.5%) (p = 0.01792). Histologically, the addition of PRP to AB accelerated the new bone formation/remodeling maintaining the percentage of new bone similar to AB/clot during all experimental volume (p = 0.6406), while the AB particles showed a higher resorption in AB/PRP than AB/clot until 60 days (mean of 7.8% and 15.1%, respectively, p = 0.0396).

CONCLUSION

The association of PRP with the autogenous graft accelerates the process of bone formation/remodeling in MSA, but not had influence on the pBCP and DBB groups.

Umbilical cord-derived Wharton's jelly for regenerative medicine applications in orthopedic surgery: a systematic review protocol

BACKGROUND

Musculoskeletal injuries and conditions affect millions of individuals. These ailments are typically managed by immobilization, physiotherapy, or activity modification. Regenerative medicine has experienced tremendous growth in the past decades, especially in musculoskeletal medicine. Umbilical cord-derived Wharton's jelly is an exciting new option for such therapies. Wharton's jelly is a connective tissue located within the umbilical cord largely composed of mesenchymal stem cells and extracellular matrix components, including collagen, chondroitin sulfate, hyaluronic acid, and sulfated proteoglycans. Wharton's jelly is a promising and applicable biologic source for orthopedic regenerative application.

METHODS

A systematic search will be conducted in PubMed, ScienceDirect, and Google Scholar databases of English, Italian, French, Spanish, and Portuguese language articles published to date. References will be screened and assessed for eligibility by two independent reviewers as per PRISMA guidelines. Articles will be considered without exclusion to sex, activity, or age. Studies will be included if they used culture-expanded, mesenchymal stem/stromal cells of mesenchymal stem cells and/or connective tissue obtained from Wharton's jelly. Studies will be excluded if Wharton's jelly is not the sole experimental examined cell type. Placebos, conventional non-operative therapies including steroid injections, exercise, and NSAIDs will be compared. The study selection process will be performed independently by two reviewers using a reference software. Data synthesis and meta-analysis will be performed separately for clinical and pre-clinical studies.

DISCUSSION

The results will be published in relevant peer-reviewed scientific journals. Investigators will present results at national or international conferences.

TRIAL REGISTRATION

The protocol was registered on PROSPERO international prospective register of systematic reviews prior to commencement, CRD42020182487 .

Platelet-rich plasma another add-on treatment getting out of hand? How can clinicians preserve the best interest of their patients?

Add-on treatments in IVF are utilized to a great extent but without sufficient evidence showing their effectiveness. Since the offered treatments are usually costly and may be associated with yet unknown risks, this practice is not in the best interest of couples that may go to great lengths to conceive and have an offspring carrying their own genetic make-up. A recent addition to this armamentarium is the administration of platelet-rich plasma (PRP) in women with diminished ovarian reserve, implantation failures, and a thin endometrium. The only evidence for PRP comes from small scale and mostly before and after studies with clinically irrelevant end points. PRP has not been subjected to a rigorous clinical trial. It is a typical example of an add-on gaining widespread popularity based on biological plausibility and mind-bending theoretical presumptions. We should be extremely cautious prior to implementing PRP on a widescale and await the results of well-designed studies.

Online resources for platelet-rich plasma injections for orthopedic therapy: What are patients reading? A survey of Turkish websites

Objectives

This study aims to evaluate the quality, accuracy, and readability of Turkish online resources for platelet-rich plasma (PRP) injections for orthopedic therapy.

Patients and methods

In this retrospective study, online searches using Google, Yandex, and Yahoo search engines were performed on 21-22-23 May 2019, respectively. “Platelet-rich plasma”, “platelet-rich plasma treatment”, “PRP”, and “PRP treatment” were entered in Turkish into these three search engines. The first 50 websites from each search were collected. The quality and accuracy of online information related to PRP injections for orthopedic therapy were evaluated by three reviewers with the use of scoring criteria specific to PRP. The Flesch-Kincaid (FK) score was used to determine readability.

Results

Eighty-six unique websites were evaluated. The average quality and accuracy scores of all websites were 7.1±4.3 out of a maximum of 25 points and 7.3±2 out of a maximum of 12 points, respectively. The average FK score of all websites was 10.8±2.2. Only 27 websites (31.4%) had a FK score that was at or below the eighth-grade level. There were no significant differences among the mean scores of websites categorized by search terms, search results ranking, owners or reading level for both quality and accuracy scores.

Conclusion

The information regarding PRP usage in orthopedic conditions provided by Turkish online resources has low quality and low accuracy ratings and is also difficult to read.

Platelet-rich plasma (PRP) as therapy for cartilage, tendon and muscle damage - German working group position statement

Purpose

Platelet rich plasma (PRP) is widely used in orthopaedics, but is still heavily debated. Therefore, a survey among the German “Working Group for Clinical Tissue Regeneration” of the German Society of Orthopaedics and Traumatology was conducted to achieve a consensus about the current therapeutical potential of PRP.

Methods

A first survey (n = 65 experts, all orthopaedic/trauma surgeons) was conducted (n = 13 questions). Following, a second round (n = 40 experts) was conducted with 31 questions to achieve consensus in 5 categories: three most common indications, PRP application, future research areas.

Results

Therapeutic PRP application was regarded as useful (89%), possibly even more important in the future (90%). Most common indications were tendon pathologies (77%), osteoarthritis (OA) (68%), muscle injuries (57%) and cartilage damage (51%). Consensus was reached in 16/31 statements. The application of PRP for early knee OA (Kellgren-Lawrence grade II) was regarded as potentially useful, as well as for acute and chronic tendinopathies. For chronic lesions (cartilage, tendons), multiple injections (2–4) were seen preferable to singular injections. However, no sufficient data exists on the time interval between the injections. Standardization of PRP preparation, application, frequency, as well as determining the range of indication is strongly recommended.

Conclusions

There is a need of further standardization of the PRP preparation methods, indication and application protocols for knee OA and other indications, which must be further evaluated in basic science studies and randomized controlled clinical trials.

Level of evidence

Consensus of expert opinion, Level V.

Dose-Dependent Effects of Platelet-Rich Plasma Powder on Chondrocytes In Vitro

BACKGROUND

Platelet-rich plasma (PRP) is widely used in sports medicine. However, neither preparation nor parameters for clinical application, such as concentration, timing, and number of applications, are standardized, making research and clinical utilization challenging.

PURPOSE

To investigate the effect of varying doses of PRP powder in terms of different concentrations, timing, and number of applications on human chondrocytes in a reproducible cell culture model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A standardized lyophilized platelet growth factor preparation (PRP powder) was used to stimulate human chondrocytes. Chondrocytes were cultivated for 2 weeks with different stimulation frequencies (2×, 3×, 6×) and different concentrations of PRP powders (0.5%, 1%, 5%). Cell proliferation and metabolic cell activity were analyzed on days 7 and 14. Phenotypic changes were visualized through live-dead staining. Chondrogenic differentiation was quantified with enzyme-linked immunosorbent assay to assess the synthesis of procollagen types 1 and 2. Furthermore, sulfated proteoglycans and glycosaminoglycans were analyzed.

RESULTS

Human chondrocytes exhibited a significant dose- and time-dependent increase after 14 days in cell number (1% and 5% PRP powder vs unstimulated control: 7.95- and 15.45-fold increase, respectively; 2× vs 6× stimulation with 5% PRP powder: 4.00-fold increase) and metabolic cell activity (1% and 5% PRP powder vs unstimulated control: 3.27-fold and 3.58-fold change, respectively). Furthermore, cells revealed a significant increase in the amount of bone-specific procollagen type 1 (14 days, 1.94-fold) and sulfated glycosaminoglycans (14 days, 2.69-fold); however, no significant change was observed in the amount of cartilage-specific collagen type 2.

CONCLUSION

We showed that chondrocytes exhibit a significant dose- and time-dependent increase in cell number and metabolic cell activity. The standardized use of growth factor concentrates in cell culture models can contribute to clinical knowledge in terms of dosage and timing of PRP applications.

CLINICAL RELEVANCE

Problems with PRP, such as the absence of standardization, lack of consistency among studies, and unknown dosage, could be solved by using characterized PRP powder made by pooling and lyophilizing multiple platelet concentrates. The innovative PRP powder generates new possibilities for PRP research, as well as for the treatment of patients.