Efficacy of Intraoperative Platelet-Rich Plasma After Meniscal Repair: Systematic Review and Meta-analysis

Background

Meniscal injuries frequently require surgical intervention to restore knee joint function and stability. Intraoperative platelet-rich plasma (PRP) injection has emerged as a potential adjunctive therapy to enhance tissue healing post-meniscal repair. This systematic review and meta-analysis aimed to evaluate the efficacy of PRP in terms of pain relief, functional recovery, and overall success rates in patients undergoing meniscal repair procedures.

Methods

A comprehensive search strategy was employed to identify relevant studies across Scopus, PubMed, Embase, and the Cochrane Library databases. The inclusion criteria encompassed human studies, including randomized controlled trials (RCTs), cohorts, and case-control studies, focusing on intraoperative platelet-rich plasma (PRP) use post-meniscal repair and reporting outcomes related to pain, functionality, and cure rates. Exclusion criteria comprised animal studies, non-English publications, studies lacking relevant outcome measures, and those with insufficient data. Two reviewers independently screened titles and abstracts, resolving disagreements through consensus or consultation with a third reviewer, followed by a full-text assessment for potentially eligible studies. Data extraction was conducted independently by two reviewers using a standardized form. The reliability of observational studies was evaluated using the Newcastle-Ottawa Scale. Subgroup analyses and pooled effect estimates for main outcomes were computed using RevMan 5.3, a meta-analysis tool.

Results

The demographic analysis revealed that the PRP group had an average age of 41.39 years, while the control group had an average age of 42.1 years. In terms of gender distribution, the PRP group consisted of 61 men and 29 women, while the control group had 62 men and 34 women. Pain ratings showed a preference for PRP with a mean difference of 4.83 (p = 0.13). However, there was no significant difference in Lysholm scores (mean difference: - 0.44, p = 0.91) or IKDC scores (mean difference: 2.80, p = 0.14) between the PRP and control groups. Similarly, ROM measures did not show a statistically significant difference, with a mean difference of 2.80 (p = 0.18). Additionally, there was no significant distinction in failure rates between the PRP and control groups, as indicated by a weighted mean difference of 0.71 (p = 0.52). These findings suggest that while PRP may offer some benefits in pain relief, its impact on functional recovery, range of motion, and failure rates following meniscal repair procedures is inconclusive.

Conclusion

The current evidence regarding the effect of intraoperative platelet-rich plasma (PRP) injection on patients undergoing meniscal repair remains inconclusive. While some studies suggest potential benefits in terms of pain relief and functional recovery, others show no significant differences compared to control groups. The impact of PRP therapy on overall success rates, including rates of re-tear and revision surgery, is also uncertain. Further well-designed randomized controlled trials with larger sample sizes are needed to provide more robust evidence and guide clinical practice in orthopedic surgery.

Effect of fenugreek oil on healing of experimentally induced buccal mucosal ulcer by immunohistochemical evaluation of Ki-67 expression

Wound healing involves multiple populations of cells, the extracellular matrix, and soluble mediators' actions like growth factors and cytokines. Wound care was the target of many research, utilizing new therapy techniques and the progression of acute and chronic wound treatments with techniques involving plants to improve healing and decrease the side effects of drugs. When fenugreek is applied to an ulcer, its anti-inflammatory components are released, reducing unnecessary inflammation and accelerating the healing process. Healing is controlled by growth factors that naturally activate and boost the proliferation of cells, such as Ki-67, which is associated with the growth fraction and represents the cell's ability to proliferate. The current study aims to assess the expression of Ki-67 in rat mucosal ulcers treated with fenugreek leave oil. Twenty-four male Wistar albino rats of 350-450 gm weight were used. The rats were grouped as follows; normal group (normal tissue without ulcer induction), control group (tissue with surgical ulcer induction on the right side), and study group (ulcer treated with fenugreek leave oil on the left side), and had been sacrificed at 3- and 7-day healing durations. Thereafter, the tissue specimens were used for immunohistochemical analysis of Ki-67. The obtained outcomes showed that expression of Ki-67 increased in groups where ulcers were induced, with significant differences between control and study groups on the 3rd day. It was concluded that the application of fenugreek oil had an accelerating effect on the healing process of mucosal ulcers, as indicated by the elevated expression level of Ki-67.

Passive microfluidic devices for cell separation

The separation of specific cell populations is instrumental in gaining insights into cellular processes, elucidating disease mechanisms, and advancing applications in tissue engineering, regenerative medicine, diagnostics, and cell therapies. Microfluidic methods for cell separation have propelled the field forward, benefitting from miniaturization, advanced fabrication technologies, a profound understanding of fluid dynamics governing particle separation mechanisms, and a surge in interdisciplinary investigations focused on diverse applications. Cell separation methodologies can be categorized according to their underlying separation mechanisms. Passive microfluidic separation systems rely on channel structures and fluidic rheology, obviating the necessity for external force fields to facilitate label-free cell separation. These passive approaches offer a compelling combination of cost-effectiveness and scalability when compared to active methods that depend on external fields to manipulate cells. This review delves into the extensive utilization of passive microfluidic techniques for cell separation, encompassing various strategies such as filtration, sedimentation, adhesion-based techniques, pinched flow fractionation (PFF), deterministic lateral displacement (DLD), inertial microfluidics, hydrophoresis, viscoelastic microfluidics, and hybrid microfluidics. Besides, the review provides an in-depth discussion concerning cell types, separation markers, and the commercialization of these technologies. Subsequently, it outlines the current challenges faced in the field and presents a forward-looking perspective on potential future developments. This work hopes to aid in facilitating the dissemination of knowledge in cell separation, guiding future research, and informing practical applications across diverse scientific disciplines.

Swarms of Enzyme-Powered Nanomotors Enhance the Diffusion of Macromolecules in Viscous Media

Over the past decades, the development of nanoparticles (NPs) to increase the efficiency of clinical treatments has been subject of intense research. Yet, most NPs have been reported to possess low efficacy as their actuation is hindered by biological barriers. For instance, synovial fluid (SF) present in the joints is mainly composed of hyaluronic acid (HA). These viscous media pose a challenge for many applications in nanomedicine, as passive NPs tend to become trapped in complex networks, which reduces their ability to reach the target location. This problem can be addressed by using active NPs (nanomotors, NMs) that are self-propelled by enzymatic reactions, although the development of enzyme-powered NMs, capable of navigating these viscous environments, remains a considerable challenge. Here, the synergistic effects of two NMs troops, namely hyaluronidase NMs (HyaNMs, Troop 1) and urease NMs (UrNMs, Troop 2) are demonstrated. Troop 1 interacts with the SF by reducing its viscosity, thus allowing Troop 2 to swim more easily through the SF. Through their collective motion, Troop 2 increases the diffusion of macromolecules. These results pave the way for more widespread use of enzyme-powered NMs, e.g., for treating joint injuries and improving therapeutic effectiveness compared with traditional methods.

Leukocyte-poor platelet-rich plasma and leukocyte-rich platelet-rich plasma promote myoblast proliferation through the upregulation of cyclin A, cdk1, and cdk2

Muscle injuries are common among athletes and often treated with platelet-rich plasma (PRP). However, whether the leukocyte concentration affects the efficacy of PRP in treating muscle injuries remains unclear. This study investigated the effects of leukocyte-poor platelet-rich plasma (LP-PRP) and leukocyte-rich platelet-rich plasma (LR-PRP) on myoblast proliferation and the molecular mechanisms underlying these effects. Myoblasts were treated with 0.5% LP-PRP, 0.5% LR-PRP, 1% LP-PRP, or 1% LR-PRP for 24 h. The gene expression of the LP-PRP- and LR-PRP-treated myoblasts was determined using RNA sequencing analysis. Cell proliferation was evaluated using an bromodeoxyuridine (BrdU) assay, and cell cycle progression was assessed through flow cytometry. The expression of cyclin A, cyclin-dependent kinase 1 (cdk1), and cdk2 was examined using Western blotting. The expression of myoblast determination protein 1 (MyoD1) was examined through Western blotting and immunofluorescence staining. The LP-PRP and LR-PRP both promoted the proliferation of myoblasts and increased differential gene expression of myoblasts. Moreover, the LP-PRP and LR-PRP substantially upregulated the expression of cyclin A, cdk1, and cdk2. MyoD1 expression was induced in the LP-PRP and LR-PRP-treated myoblasts. Our results corroborate the finding that LP-PRP and LR-PRP have similar positive effects on myoblast proliferation and MyoD1 expression.

Regenerative Medicine Applied to Musculoskeletal Diseases in Equines: A Systematic Review

Musculoskeletal injuries in horses have a great economic impact, predominantly affecting tendons, ligaments, and cartilage, which have limited natural regeneration. Cell therapy, which uses mesenchymal stem cells due to their tissue differentiation properties and anti-inflammatory and immunoregulatory effects, aims to restore damaged tissue. In this manuscript, we performed a systematic review using the Parsifal tool, searching the PubMed and Web of Science databases for articles on regenerative medicine for equine musculoskeletal injuries. Our review covers 17 experimental clinical studies categorized by the therapeutic approach used: platelet-rich plasma, conditioned autologous serum, mesenchymal stem cells, and secretome. These therapies reduce healing time, promote regeneration of fibrocartilaginous tissue, improve cellular organization, and improve joint functionality and sustainability. In conclusion, regenerative therapies using platelet-rich plasma, conditioned autologous serum, equine mesenchymal stem cells, and the emerging field of the secretome represent a promising and highly effective approach for the treatment of joint pathologies in horses, implying a valuable advance in equine healthcare.

Hamstring Injury Treatments and Management in Athletes: A Systematic Review of the Current Literature

BACKGROUND

The field of sports medicine presents a varied landscape of research on hamstring injuries in athletes, characterized by inconclusive and sometimes conflicting findings on effective treatment and rehabilitation strategies. This discordance prompted the current systematic investigation.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for conducting the systematic review. Multiple international bibliometric databases (Scopus, PubMed, Web of Science, and Embase) were searched to identify studies evaluating any treatment option for the management of hamstring injuries in athletes. Eligible studies were appraised for quality using Joanna Briggs Institute and Risk of Bias 2 tools.

RESULTS

A total of 30 studies with 1,195 participants were included. Of the reviewed studies, treatments varied from aggressive rehabilitation, platelet-rich plasma (PRP) injections, manual techniques, various exercise protocols to modalities like high-power laser and nonsteroidal anti-inflammatory drugs. Evidence suggested benefits from treatments like extensive muscle lengthening during eccentric actions, progressive agility, and trunk stabilization. PRP injections produced mixed results regarding return to sport and reinjury rates. Stretching exercises, sometimes combined with cryotherapy, showed benefits.

CONCLUSION

Treatments for hamstring injuries exhibit varied efficacy. Although rest, ice, compression, and elevation remains essential for acute management, rehabilitation focusing on muscle strengthening and flexibility is crucial. The potential benefits of PRP injections, especially for chronic cases, require more conclusive research. A comprehensive approach, combining evidence-based practices and patient-centric factors, is vital for effective management and recovery.

LEVEL OF EVIDENCE

Level IV. See Instructions for Authors for a complete description of levels of evidence.

Orthobiologics: a review

PURPOSE

The use of biologic materials in orthopaedics (orthobiologics) has gained significant attention over the past years. To enhance the body of the related literature, this review article is aimed at summarizing these novel biologic therapies in orthopaedics and at discussing their multiple clinical implementations and outcomes.

METHODS

This review of the literature presents the methods, clinical applications, impact, cost-effectiveness, and outcomes, as well as the current indications and future perspectives of orthobiologics, namely, platelet-rich plasma, mesenchymal stem cells, bone marrow aspirate concentrate, growth factors, and tissue engineering.

RESULTS

Currently available studies have used variable methods of research including biologic materials as well as patient populations and outcome measurements, therefore making comparison of studies difficult. Key features for the study and use of orthobiologics include minimal invasiveness, great healing potential, and reasonable cost as a nonoperative treatment option. Their clinical applications have been described for common orthopaedic pathologies such as osteoarthritis, articular cartilage defects, bone defects and fracture nonunions, ligament injuries, and tendinopathies.

CONCLUSIONS

Orthobiologics-based therapies have shown noticeable clinical results at the short- and mid-term. It is crucial that these therapies remain effective and stable in the long term. The optimal design for a successful scaffold remains to be further determined.

Endoscopic debridement for non-insertional Achilles tendinopathy with and without platelet-rich plasma

BACKGROUND

When non-operative management fails to improve symptoms in patients with non-insertional Achilles tendinopathy, surgery may be required. Various open and endoscopic techniques have been proposed, and platelet-rich plasma (PRP) injections have been proposed as an adjunct to aid tendon healing.

METHODS

Thirty-six patients with mid-portion Achilles tendinopathy were randomized to undergo endoscopic debridement alone (n = 19) or in combination with intraoperative PRP application (n = 17). Clinical outcome measures included the Visual Analogue Scale for pain, function, and satisfaction and the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire. Patients were followed-up at 6 weeks, 3 months, 6 months, and 12 months after surgery. An MRI examination at 3 and 12 months was used to assess signal alterations within the tendon.

RESULTS

Both groups showed significant clinical improvement (p < 0.05) after surgery, with no difference between the 2 groups. Tendon diameter increased at 3 months and decreased at 12 months. The tendinopathy area increased at 3 months and decreased at 12 months below baseline level in both groups. There was no significant difference between the groups regarding the MRI parameters. Nodular thickening and MRI-detected signal alteration persisted after surgery, with no association between imaging and clinical outcome. Five minor complications were reported: 2 in the PRP group and 3 in the control group.

CONCLUSION

Endoscopic debridement of the Achilles tendon improved clinical outcomes in patients with mid-portion tendinopathy. The addition of PRP did not improve outcomes compared to debridement alone. MRI parameters showed no association with clinical outcomes.

Freeze-dried Platelet-rich Plasma and Stem Cell-conditioned Medium for Therapeutic Use in Horses

This study investigated platelet-rich plasma (PRP) and adipose stem cell-conditioned medium (ASC-CM) use as a strategy to accelerate tissue healing. Platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) were quantified in fresh and freeze-dried PRP and ASC-CM, and a stability test was performed in the freeze-dried samples (90 and 180 days of storage). A cell proliferation test was performed using equine mesenchymal stem cell culture in reconstituted PRP gel mesh after freeze-drying. In vivo PRP, ASC-CM applications, or their association were performed in induced wounds at 15 and 9-day intervals, according to the treatments: saline solution (control), PRP, ASC-CM, or ASC-CM + PRP. Horses were monitored through photographs and wound area measurements on days 5, 7, 15, and 24 after lesion induction. Skin biopsies were obtained on days 15 and 24 of the experiment. PDGF and VEGF quantification did not differ between fresh or freeze-dried treatments, was similar after freeze-drying or 90 days of storage, but showed a significant reduction after 180 days of storage. Comparing all treatments, no differences were observed in the histopathological analyses. For inflammation, fibroplasia, and collagen formation, only the time effect between the first and second biopsies was significant. The cell proliferation test revealed intense multiplication in the PRP gel mesh. Healing time was similar among all treatments. In conclusion, our results showed the possibility to produce and maintain freeze-dried PRP and ASC-CM for 90 days. Further studies are needed to better explore the in vivo therapeutic PRP and ASC-CM effects.

Efficacy of Platelet-Rich Plasma Versus Placebo in the Treatment of Tendinopathy: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To evaluate the efficacy of platelet-rich plasma (PRP) injections versus placebo in the treatment of tendinopathy.

DATA SOURCES

We performed a systematic literature search in MEDLINE, Embase, Scopus, CINAHL, Cochrane Library, and ClinicalTrials.gov through November 2020 to identify randomized controlled trials (RCTs) that evaluated the clinical efficacy of PRP versus placebo for the treatment of tendinopathy. Outcomes were analyzed on an intention-to-treat basis with random-effects models.

MAIN RESULTS

A total of 13 RCTs were included in this meta-analysis. The pooled analysis showed no significant difference in pain relief at 4 to 6 weeks (standard mean difference [SMD]: -0.18, 95% confidence intervals [CI]: -0.62 to 0.26), 12 weeks (SMD: -0.14, 95% CI: -0.55 to 0.26), and ≥24 weeks (SMD: -0.56, 95% CI: -1.16 to 0.05) or function improvement at 4 to 6 weeks (SMD: 0.11, 95% CI: -0.13 to 0.35), 12 weeks (SMD: 0.18, 95% CI: -0.13 to 0.49), and ≥24 weeks (SMD: 0.26, 95% CI: -0.14 to 0.66) for PRP compared with placebo in the treatment of tendinopathy. The sensitivity analysis indicated no significant difference in pain relief or function improvement at 12 weeks between PRP and placebo for different types of tendinopathies, treatment regimens, leukocyte concentrations, or cointerventions.

CONCLUSIONS

Platelet-rich plasma injection was not found to be superior to placebo in the treatment of tendinopathy, as measured by pain relief and functional improvement at 4 to 6, 12, and ≥24 weeks.

Histological and biochemical evaluation of plasma rich in growth factors treatment for grade II muscle injuries in sheep

The purpose of this study was to perform a histological and biochemical evaluation of the influence of plasma rich in growth factors (PRGF) on muscle regeneration process after a surgically induced grade II muscle laceration. A randomized, single blind, controlled experimental research was conducted including twenty-one adult healthy sheep, randomly divided in three groups (n = 7). A grade II surgical section was performed in the biceps femoris muscle of both hindlimbs. After two days (basal time), intralesional infiltration of autologous PRGF or Saline solution was randomly administered in both hindlimbs. Treatment was repeated once a week. Animal groups were euthanized at 1 (T1), 2 (T2) or 4 (T4) weeks. Histological assessment showed that PRGF intralesional injection induced a significant decrease of inflammatory cells density, significant higher centrally nucleated fibers percentage and significantly smaller fibrotic areas compared to Saline-treated muscles at T1, T2 and T4. Also, lower vascular density, with lower capillaries cross-sectional area, in PRGF group compared to Saline was observed. Biochemical analysis revealed a significant higher expression level of MYOD1, MYF5 and MYOG genes in PRGF groups at T1 compared to Saline treated muscles. At ultrastructural level, PRGF groups presented scarce edema and loss of connective tissue structure, as well as higher mitochondrial density adequately associated to the sarcomere unit in contrast to the Saline group. In conclusion, histological, biochemical, and ultrastructural results showed that PRGF treatment improved muscle regeneration process leading to more mature histological aspect in newly formed muscle tissue after a surgically induced grade II muscle injury.

Creating an Optimal In Vivo Environment to Enhance Outcomes Using Cell Therapy to Repair/Regenerate Injured Tissues of the Musculoskeletal System

Following most injuries to a musculoskeletal tissue which function in unique mechanical environments, an inflammatory response occurs to facilitate endogenous repair. This is a process that usually yields functionally inferior scar tissue. In the case of such injuries occurring in adults, the injury environment no longer expresses the anabolic processes that contributed to growth and maturation. An injury can also contribute to the development of a degenerative process, such as osteoarthritis. Over the past several years, researchers have attempted to use cellular therapies to enhance the repair and regeneration of injured tissues, including Platelet-rich Plasma and mesenchymal stem/medicinal signaling cells (MSC) from a variety of tissue sources, either as free MSC or incorporated into tissue engineered constructs, to facilitate regeneration of such damaged tissues. The use of free MSC can sometimes affect pain symptoms associated with conditions such as OA, but regeneration of damaged tissues has been challenging, particularly as some of these tissues have very complex structures. Therefore, implanting MSC or engineered constructs into an inflammatory environment in an adult may compromise the potential of the cells to facilitate regeneration, and neutralizing the inflammatory environment and enhancing the anabolic environment may be required for MSC-based interventions to fulfill their potential. Thus, success may depend on first eliminating negative influences (e.g., inflammation) in an environment, and secondly, implanting optimally cultured MSC or tissue engineered constructs into an anabolic environment to achieve the best outcomes. Furthermore, such interventions should be considered early rather than later on in a disease process, at a time when sufficient endogenous cells remain to serve as a template for repair and regeneration. This review discusses how the interface between inflammation and cell-based regeneration of damaged tissues may be at odds, and outlines approaches to improve outcomes. In addition, other variables that could contribute to the success of cell therapies are discussed. Thus, there may be a need to adopt a Precision Medicine approach to optimize tissue repair and regeneration following injury to these important tissues.

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.

The Role of Hyaluronic Acid for Soft Tissue Indications: A Systematic Review and Meta-Analysis

CONTEXT

Soft tissue injuries are often treated with injectables such as corticosteroids and platelet-rich plasma (PRP) to reduce inflammation and promote healing. There is increasing evidence examining the use of hyaluronic acid (HA) for the management of soft tissue injuries.

OBJECTIVE

To evaluate the treatment effect and role of HA for available soft tissue indications.

DATA SOURCES

A search of PubMed, MEDLINE, EMBASE, and CENTRAL from the inception date of each database through February 24, 2021, was conducted for all randomized controlled trials (RCTs) involving the use of HA for soft tissue indications. Two reviewers independently screened articles for eligibility and extracted data from included studies for analysis. We assessed risk of bias for all included studies and pooled outcomes using a fixed-effects model. Outcomes (ie, function and pain relief) were categorized to short-term (<6 weeks, 6-12 weeks) and mid-term (>12 weeks) data. We present effect estimates as mean differences (MDs) and standardized mean differences (SMDs) and present the estimate of effect of HA for available indications in relation to available comparators.

STUDY DESIGN

Meta-analysis of RCTs.

LEVEL OF EVIDENCE

Level 1.

RESULTS

Of the 6930 articles screened, 19 RCTs (n = 1629 patients) were eligible and included in this review. HA was evaluated across a variety of soft tissue indications including rotator cuff disease, elbow pain, ankle sprains, Achilles tendinopathy, patellar tendinopathy, and trigger finger. Of the 19 RCTs, 11 were placebo-controlled and 9 used active comparators (PRP, cortisone, prolotherapy, or extracorporeal shockwave therapy). The pooled treatment effect of HA across most soft indications against placebo and active comparators demonstrated benefit in short-term pain <6 weeks (MD visual analogue scale [VAS] 2.48, 95% CI 2.31-2.65) and 6 to 12 weeks (MD VAS 2.03, 95% CI 1.86-2.20). Mid-term pain relief also favored HA over comparators across indications >12 weeks from administration (MD VAS 3.57, 95% CI 3.35-3.78). High heterogeneity was present with rotator cuff (10 trials, I² = 94%), and elbow tendinopathy (2 trials, I² = 99%). We identified uncertain benefit for trigger finger (2 trials, I² = 67%). Heterogeneity for ankle sprains, patellar tendinopathy and Achilles tendinopathy could not be assessed as they only had 1 trial each.

CONCLUSION

This systematic review and meta-analysis support HA's efficacy in the treatment of a variety of soft tissue indications. Understanding the relative effects of HA to other injectable modalities requires additional, large trials.

Feasibility of Growth Factor Agent Therapy in Repairing Motor Injury

Growth factors (GF), with the activity of stimulating cell growth, play a significant role in biology, medicine, and exercise physiology. In the process of exercise, human tissues are impacted, making cells suffer damage. Growth factor can accelerate the repair of damaged cells and regulate the synthesis of protein, so biological preparations of growth factors can be added to traditional therapies. A combination of growth factor biologics and conventional therapies may improve the efficiency of injury repair, but growth factor biologics may not produce any results. The feasibility of growth factor biologics in the treatment of motor injury was discussed. The research have shown that: 1) GF biological agent therapy is a very promising treatment for motor injury, which is based on the power of autologous growth factor (GFs) to accelerate tissue healing, promote muscle regeneration, increase angiogenesis, reduce fibrosis, and make the muscle injury rapid recovery. 2) There are various methods for delivering the higher dose of GF to the injured tissue, but most of them depend on the platelet release of GF. At the site of injury, there are several ways to deliver higher doses of GF to the injured tissue. 3) At present, the inhibition of GF is mainly through signal transduction inhibitors and inhibition of transcription factor production. 4) Pattern of GF during wound repair: GF directly regulates many key steps of normal wound repair, including inflammatory cell chemotaxis, division and proliferation of fibroblasts, keratinocytes and vascular endothelial cells, formation of new blood vessels, and synthesis and degradation of intercellular substances. 5) When GF promotes chronic wound healing, in most cases, certain GF can be used targeted only when in vivo regulation still cannot meet the need for repair.

Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Chondral Injuries In Young Patients

Objective  The present study aimed to compare the clinical and functional outcomes of hyaluronic acid (HA) or platelet-rich plasma (PRP) applications to treat young patients with knee chondral lesions with no arthrosis.

Methods  Prospective clinical and functional evaluation of 30 young adult patients with knee chondral lesions submitted to conservative treatment with HA or PRP for a minimum follow-up time of 12 months. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) and visual analog scale (VAS) were used for the evaluation.

Results  According to the WOMAC score, the PRP group showed significant improvement in all evaluated points, whereas the HA group presented no score improvement. In the VAS, the PRP group showed improvement in all evaluated points, and the HA group presented improvement at 6 and 12 months. Compared to the HA group, the PRP group presented better WOMAC scores at all evaluated points and better VAS scores up to 6 months after treatment.

Conclusion  Platelet-rich plasma application resulted in better clinical and functional outcomes at both the WOMAC and VAS scores when applied to knees from young patients with chondral lesions, but no arthrosis. These outcomes were sustained for up to 12 months.

Level of evidence  Randomized clinical trial (Type 2B)

Nerve guidance conduit development for primary treatment of peripheral nerve transection injuries: A commercial perspective

Commercial nerve guidance conduits (NGCs) for repair of peripheral nerve discontinuities are of little use in gaps larger than 30 mm, and for smaller gaps they often fail to compete with the autografts that they are designed to replace. While recent research to develop new technologies for use in NGCs has produced many advanced designs with seemingly positive functional outcomes in animal models, these advances have not been translated into viable clinical products. While there have been many detailed reviews of the technologies available for creating NGCs, none of these have focussed on the requirements of the commercialisation process which are vital to ensure the translation of a technology from bench to clinic. Consideration of the factors essential for commercial viability, including regulatory clearance, reimbursement processes, manufacturability and scale up, and quality management early in the design process is vital in giving new technologies the best chance at achieving real-world impact. Here we have attempted to summarise the major components to consider during the development of emerging NGC technologies as a guide for those looking to develop new technology in this domain. We also examine a selection of the latest academic developments from the viewpoint of clinical translation, and discuss areas where we believe further work would be most likely to bring new NGC technologies to the clinic. STATEMENT OF SIGNIFICANCE: NGCs for peripheral nerve repairs represent an adaptable foundation with potential to incorporate modifications to improve nerve regeneration outcomes. In this review we outline the regulatory processes that functionally distinct NGCs may need to address and explore new modifications and the complications that may need to be addressed during the translation process from bench to clinic.

Autologous platelet concentrates in oral surgery: protocols, properties, and clinical applications

Autologous platelet concentrates (APCs) are a relatively new phenomenon, with initial reports of their regenerative potential published as recently as 1998. Despite their relative infancy, a huge body of evidence exists in support of their capacity to promote osseous and soft tissue regeneration through the physiologic processes of platelet activation and subsequent growth factor release. APCs have transformed many areas of healthcare and are now considered an essential component of the surgical milieu. In this narrative review, we explore the evolution of autologous platelet therapies with a particular emphasis on their contemporary applications in oral surgery, which rather fittingly was the first specialty to report the regenerative potential of APCs.

Use of Platelet-Rich Plasma Plus Suramin, an Antifibrotic Agent, to Improve Muscle Healing After Injuries

BACKGROUND

The increasing use of platelet-rich plasma (PRP) to treat muscle injuries raises concerns because transforming growth factor-beta (TGF-β) in PRP may promote fibrosis in the injured muscle and thus impair muscle regeneration.

PURPOSE

To investigate whether suramin (a TGF-β inhibitor) can reduce muscle fibrosis to improve healing of the injured muscle after PRP treatment and identify the underlying molecular mechanism.

STUDY DESIGN

Controlled laboratory study.

METHODS

Myoblasts isolated from the gastrocnemius muscle of Sprague Dawley rats were treated with PRP or PRP plus suramin. MTT assays were performed to evaluate cell viability. The expression of fibrosis-associated proteins (such as type I collagen and fibronectin), Smad2, and phosphorylated Smad2 was determined using Western blot analysis and immunofluorescent staining. An anti-TGF-β antibody was employed to verify the role of TGF-β in fibronectin expression. Gastrocnemius muscles were injured through a partial transverse incision and then treated using PRP or PRP plus suramin. Hematoxylin and eosin staining was conducted to evaluate the healing process 7 days after the injury. Immunofluorescent staining was performed to evaluate fibronectin expression. Muscle contractile properties-fast-twitch and tetanic strength-were evaluated through electric stimulation.

RESULTS

PRP plus 25 μg/mL of suramin promoted myoblast proliferation. PRP induced fibronectin expression in myoblasts, but suramin reduced this upregulation. The anti-TGF-β antibody also reduced the upregulation of fibronectin expression in the presence of PRP. The upregulation of phosphorylated Smad2 by PRP was reduced by either the anti-TGF-β antibody or suramin. In the animal study, no significant difference was discovered in muscle healing between the PRP versus PRP plus suramin groups. However, the PRP plus suramin group had reduced fibronectin expression at the injury site. Fast-twitch strength and tetanic strength were significantly higher in the injured muscle treated using PRP or PRP plus suramin.

CONCLUSION

Simultaneous PRP and suramin use reduced fibrosis in the injured muscle and promoted healing without negatively affecting the muscle's contractile properties. The underlying molecular mechanism may be associated with the phosphorylated Smad2 pathway.

CLINICAL RELEVANCE

Simultaneous PRP and suramin use may reduce muscle fibrosis without compromising muscle contractile properties and thus improve muscle healing.

Use of Autologous Leucocyte- and Platelet-Rich Plasma (L-PRP) in the Treatment of Aural Hematoma in Dogs

Leukocyte- and platelet-rich plasma (L-PRP) can accelerate the healing process by providing increased concentrations of platelet-derived growth factors. The objective of this study was to evaluate the clinical effect of L-PRP in the treatment of canine aural hematomas associated with otitis externa. Twenty mL of citrated whole blood was collected from each of the 17 dogs included and autologous L-PRP was produced. The aural hematoma was drained and 0.5–1 mL of L-PRP was injected. The dogs were examined weekly until 7 days after complete clinical healing. A final clinical follow-up was performed 6 weeks after the first treatment with L-PRP. If there was recurrence of the aural hematoma at the first follow-up, the treatment was repeated. In total, 2/17 cases were lost after the first follow-up. In 5/17 dogs, a short-term recurrence occurred. In 12/15 cases, complete clinical resolution was achieved with a single L-PRP application (Group A1) and in 3/15 with two treatments (Group A2). The mean time to complete clinical resolution was 16 ± 8.7 days (A1) and 23.3 ± 4 days (A2), respectively. No side effects were reported. The in situ administration of autologous L-PRP resulted in a complete resolution of the aural hematoma in all dogs that completed the clinical trial.

The 2020 NBA Orthobiologics Consensus Statement

This 2020 NBA Orthobiologics Consensus Statement provides a concise summary of available literature and practical clinical guidelines for team physicians and players. We recognize that orthobiologic injections are a generally safe treatment modality with a significant potential to reduce pain and expedite early return to play in specific musculoskeletal injuries. The use of orthobiologics in sports medicine to safely reduce time loss and reinjury is of considerable interest, especially as it relates to the potential effect on a professional athlete. While these novel substances have potential to enhance healing and regeneration of injured tissues, there is a lack of robust data to support their regular use at this time. There are no absolutes when considering the implementation of orthobiologics, and unbiased clinical judgment with an emphasis on player safety should always prevail. Current best evidence supports the following: Key Points There is support for the use of leukocyte-poor platelet-rich plasma in the treatment of knee osteoarthritis. There is support for consideration of using leukocyte-rich platelet-rich plasma for patellar tendinopathy. The efficacy of using mesenchymal stromal cell injections in the management of joint and soft tissue injuries remains unproven at this time. There are very few data to suggest that current cell therapy treatments lead to any true functional tissue regeneration. Meticulous and sterile preparation guidelines must be followed to minimize the risk for infection and adverse events if these treatments are pursued.Given the high variability in orthobiologic formulations, team physicians must stay up-to-date with the most recent peer-reviewed literature and orthobiologic preparation protocols for specific injuries.Evidence-based treatment algorithms are necessary to identify the optimal orthobiologic formulations for specific tissues and injuries in athletes.Changes in the regulatory environment and improved standardization are required given the exponential increase in utilization as novel techniques and substances are introduced into clinical practice.

Platelet-Rich Plasma Applications for Achilles Tendon Repair: A Bridge between Biology and Surgery

Achilles tendon ruptures are very common tendon ruptures and their incidence is increasing in modern society, resulting in work incapacity and months off sport, which generate a need for accelerated and successful therapeutic repair strategy. Platelet-rich plasma (PRP) is emerging as adjuvant human blood-derived constructs to assist Achilles tendon rupture treatment. However, myriad PRP preparation methods in conjunction with poor standardization in the modalities of their applications impinge on the consistent effectiveness of clinical and structural outcomes regarding their therapeutic efficacy. The purpose of this review is to provide some light on the application of PRP for Achilles tendon ruptures. PRP has many characteristics that make it an attractive treatment. Elements such as the inclusion of leukocytes and erythrocytes within PRP, the absence of activation and activation ex vivo or in vivo, the modality of application, and the adjustment of PRP pH can influence the biology of the applied product and result in misleading therapeutic conclusions. The weakest points in demonstrating their consistent effectiveness are primarily the result of myriad PRP preparation methods and the poor standardization of modalities for their application. Selecting the right biological scaffold and applying it correctly to restitutio ad integrum of ruptured Achilles tendons remains a daunting and complex task.

Role of Platelet Rich Plasma (PRP) injection in treatment of rotator cuff tear

Background

One of the commonest causes of shoulder pain and disability is partial thickness tear of the rotator cuff. Platelet-rich plasma (PRP) therapy is a volume of the plasma fraction of autologous blood that has platelet concentration above the baseline. It is theorized that PRP may help stimulate the development of normal-appearing histologic tissue characteristics at the repair site and improve clinical outcomes. Our purpose is to assess the efficacy of PRP therapy in treatment of rotator cuff tear. This prospective single-center study involved 30 patients (aged 31.7 ± 7.7 years, 63.3% males) complaining of symptomatic rotator cuff tear. Platelet-rich plasma (PRP) injection was done to all patients. Before and after injection of PRP, scoring was done using visual analog score, Shoulder Pain and Disability Index (SPADI), and musculoskeletal ultrasound scoring of the tear. Reassessment was done 4 weeks after the injections.

Results

The pre-injection VAS pain score was 7.1 ± 0.99 after injection, and it became 3.7 ± 1.09. Also, SPADI score decreased from 78.03 ± 8.25 pre-injection to 42.1 ± 13.97 post-injection. There was a highly statistically significant difference in VAS pain score and SPADI score before and after PRP injection (p < 0.001). There was highly statistically significant positive correlation between the improvement of US grading score change and the improvement of VAS score change, and between it and SPADI improvement change (r = 0.695, p < 0.001 and r = 0.693, p < 0.001, respectively). There was a highly statistically significant difference between US grading score before and after PRP injection (p < 0.001).

Conclusion

PRP can be considered an effective method for treatment of rotator cuff tear and less invasive compared to surgical treatment. It improves the pain, shoulder function, and tear size.

Parecoxib alleviates the inflammatory effect of leukocyte-rich platelet-rich plasma in normal rabbit tendons

Background

Platelet-rich plasma (PRP) is widely used to treat tendon injuries. Its therapeutic effect varies depending on the different cell components, and white blood cells (WBCs) may play an important role in this phenomenon. The purpose of this study was to evaluate how PRP with different concentrations of WBCs affect normal rabbit tendon and assess whether non-steroidal anti-inflammatory drugs (NSAIDs) can suppress the catabolic effects of WBCs.

Methods

Sixteen adult New Zealand White rabbits were used. Blood samples were collected from each rabbit, and PRP was extracted following two different protocols to obtain leukocyte-poor PRP (LP-PRP) and leukocyte-rich PRP (LR-PRP). LP-PRP or LR-PRP was injected into the patellar tendon of each rabbit, while normal saline (NS) was injected as control. In LR-PRP + NSAID group, Parecoxib was administered after LR-PRP injection. For each group, 2 rabbits were euthanatized at day 5 and 14. The patellar tendons were collected and stained with hematoxylin and eosin. A semi-quantitative approach was used to assess the inflammatory response and tendon destruction based on the evaluation of the WBCs, vascularization, fiber structure, and fibrosis.

Results

The LR-PRP group exhibited a higher total tendon score than the LP-PRP group at day 5 after PRP injection, but there was no significant difference between the two groups at day 14. For the NSAID group, the tendon score was lower than that of the LR-PRP group both at day 5 and 14.

Conclusion

LR-PRP can promote a higher inflammatory response than LP-PRP in the normal rabbit patellar tendon, and this effect can be suppressed by NSAIDs.

Platelet rich plasma versus extracorporeal shock wave therapy in patients with non-calcific supraspinatous tears

Background

To compare the clinical efficacy of platelet rich plasma (PRP) subacromial injection and extracorporeal shock wave therapy (ESWT) on refractory non-calcific partial thickness supraspinatous tendon tear.

Results

Significant improvement in all outcome measures achieved in both groups at 4 weeks follow-up period (the end of treatment course) (P< 0.05). At 12 weeks follow-up period, group I, showed significant improvement in all outcome measures compared to baseline and group II; however, in group II, there was no significant difference compared to baseline; moreover, deterioration in the previous improvement was noticed.

Conclusion

Both PRP (group I) and ESWT (group II) are effective therapeutic methods in the management of refractory non-calcific partial thickness supraspinatous tendon tear; however, PRP (group I) has better long-term effects on both pain and function.

Comparison of midterm results of Platelet Rich Plasma (PRP) versus Steroid for plantar fasciitis: A randomized control trial of 118 patients

BACKGROUND

Plantar fasciitis, which is a common cause of heel pain, often results in significant morbidity. In cases who are not responsive to initial conservative treatment, invasive procedures, often in the form of local infiltration of steroid are required. These procedures are associated with significant complications. Local Platelet Rich Plasma (PRP) infiltration is an emerging addition to these treatments. However, whether it is more effective in reducing pain and improving function than other treatments (such as steroid injections or whole blood) remains controversial.

METHODS

Skeletally mature patients with plantar fasciitis who had failed conservative therapy were randomized using envelope method into 2 groups: PRP and Steroid group. The participants were assessed for pain using Visual Analog Scale on the day of presentation, and then after therapy at 2 weeks, 4 weeks, 3 months, and 6 months. They were additionally assessed on final follow-up using AOFAS hind-foot Score.

RESULTS

118 patients were randomized into 2 groups: 58 patients to the PRP group and 60 to the Steroid group. PRP was associated with greater improvement in VAS score and resulted in superior AOFAS score at 6 months as compared to steroid injection. The authors did not find any local or systemic complications in any of the groups. The result and difference were more pronounced as the time from injection increased and maximal benefit was observed at 6 months follow-up. None of the patients needed a repeat injection at 6 months.

CONCLUSION

Our study expands on the previous studies to provide a better evidence for superiority of PRP over local injection of steroid in plantar fasciitis, and the authors conclude that PRP provides better pain relief and function as compared to steroid injection.

LEVEL OF EVIDENCE

Level 1 Prospective Randomized Control Trial (RCT).

Platelet rich plasma for treatment of osteochondral lesions of the talus: A systematic review of clinical trials

BACKGROUND

The ankle is the second most frequent site, following the knee, that requires cartilage repair. Osteochondral lesion of the talus (OLT) is common among athletes and is a result of talar cartilage detachment with or without subchondral bone fragmentation after a traumatic event. Treatment strategies for OLT can be classified as reparative or replacement interventions, with the former taking precedence. Recent studies show that the growth factors and bioactive components in platelet rich plasma (PRP) could improve cartilage regeneration. The prospect of using autologous blood to obtain a product that could enhance regeneration in damaged cartilage has been regarded as innovative, as it could circumvent the need for a replacement, and potentially join the ranks of first line reparative interventions against cartilage diseases.

METHODS

Literature searches were performed across seven search engines for randomized controlled trials using PRP to treat patients with OLT. Outcomes extracted included ankle function and pain measures. Level of evidence and methodological quality were evaluated using relevant guidelines.

RESULTS

Four studies met the eligibility criteria and were systematically appraised. Two studies scored Level 1 and 2 scored Level 2 based on the LOE assessment. MQOE evaluation revealed one study with excellent quality, and three with good quality. Overall results showed that PRP, as an adjunct to microfracture surgery, significantly improved function and reduced pain compared to microfracture surgery alone. Intra-articular PRP injection also demonstrated significantly enhanced recovery of function, and decreased pain scores compared to HA.

CONCLUSION

PRP improves joint function, and reduces pain in patients with OLT regardless of the method of implementation. In addition, inter-study comparison demonstrated that patients that received surgery along with PRP injections improved more than those that received PRP only. The studies that corroborate this conclusion have high levels of evidence with satisfactory methodological quality.

LEVEL OF EVIDENCE

Level 2, systematic review of Level 1 and 2 studies.

Does the Application of Platelet-Rich Fibrin in Anterior Cruciate Ligament Reconstruction Enhance Graft Healing and Maturation? A Comparative MRI Study of 44 Cases

Background:

Anterior cruciate ligament (ACL) reconstruction performed with growth factors and activated platelets has been suggested to accelerate tendon ligamentization, leading to earlier return to daily activities and sports.

Hypotheses:

Platelet-rich fibrin (PRF) will result in improved graft maturation and healing as evaluated by magnetic resonance imaging (MRI) in patients undergoing hamstring ACL reconstruction. Hemostatic and analgesic properties of PRF will lead to less postoperative blood loss and pain.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 44 patients with isolated ACL injuries who underwent arthroscopic all-inside anatomic single-bundle ACL reconstruction with semitendinosus tendon graft were enrolled. Group 1 included 23 patients who had PRF sprayed to the surface of the graft; group 2 included 21 patients for whom no PRF was used. Patients were discharged after 24 hours and examined for hemarthrosis that needed to be aspirated. MRI was performed at the fifth postoperative month. A blinded radiologist evaluated graft maturation according to its signal intensity and the presence of synovial fluid at the tunnel-graft interface.

Results:

PRF-treated grafts demonstrated lower MRI signal intensity and less fluid in the graft-tunnel interface as compared with controls for the entire length of the graft. The mean full-length MRI signal intensities were 9.19 versus 16.59 (P = .047) for groups 1 and 2, respectively. Subgroup analysis of the semitendinosus grafts demonstrated a signal intensity of 11.57 versus 23.98 (P = .044) for the proximal third, 9.53 versus 13.83 (P = .237) for the midbody, and 6.48 versus 11.98 (P = .087) for the distal third. Synovial fluid at the graft-tunnel interface was detected in 1 patient in group 1 (4.3%) and 3 patients in group 2 (14.3%; P < .001). Patients in group 1 had significantly less hemarthrosis that needed to be aspirated (P = .003), while postoperative analgesia requirements were similar in both groups (P = .08). No clinical benefit of PRF could be demonstrated in clinical outcomes.

Conclusion:

Application of PRF led to superior graft integration and maturation in the proximal third of the ACL graft. There was no significant difference in MRI signal intensity in the midbody or distal tibial graft. Application of PRF also resulted in significantly lower rates of postoperative hemarthrosis that needed to be aspirated.

Proteomic Classification and Identification of Proteins Related to Tissue Healing of Platelet-Rich Plasma

Background

Platelet-rich plasma (PRP) is a plasma component of autologous blood containing a high concentration of platelets. PRP is used to promote healing of damaged tissues. However, there are not many studies on the composition and expression patterns of active proteins in PRP. The purpose of this study was to identify unknown factors that contribute to tissue healing by proteomic analysis of proteins in PRP.

Methods

Three men in their 30s with no basal disease participated in this study. All identified proteins were classified for tissue healing-related functions on the basis of the gene ontology analysis of adhesion molecule with Ig-like domain 2 (AmiGO2). PRP was prepared by using the ACP kit and GPS III kit.

Results

We identified a total of 125 proteins related to wound healing, along with three proteins for angiogenesis involved in wound healing, two proteins for fibroblast migration, four proteins for collagen biosynthesis process, two proteins for glycosaminoglycan biosynthesis process, and 13 proteins for glycosaminoglycan binding. So, in addition to the growth factors that have been already known to be involved in tissue healing, 25 new proteins were identified.

Conclusions

We identified the unknown proteins associated with tissue healing in PRP. Our findings may serve as a foundation for the establishment of basic medical evidence for PRP applications.

Novel Cryopreservation Approach Providing Off-the-Shelf Availability of Human Multipotent Mesenchymal Stromal Cells for Clinical Applications

Cryopreservation is the only established method to provide long-term storage and fast availability of cellular product for therapeutic applications. The overwhelming majority of cryopreservation media contain toxic concentrations of dimethyl sulfoxide (DMSO) limiting the possibility for the direct administration of cryopreserved cells to the patients. Here, we propose a novel approach for nontoxic xeno-free cryopreservation of human multipotent mesenchymal stromal cells (MSCs) aimed at ensuring high viability, ready-to-use availability, and localized delivery of the cell-based graft into damaged tissues. For MSC cryopreservation, we applied sucrose pretreatment procedure and xeno-free cryoprotective medium containing human platelet-poor blood plasma (PPP), sucrose, and nontoxic concentration of DMSO. Using the combination of PPP, 0.2 M sucrose, and 1% DMSO, the recovery rate of cryopreserved MSCs reached 73% of the values obtained for noncryopreserved cells. Moreover, the presence of PPP in the cryoprotective medium provided the possibility to create a ready-to-use 3D hydrogel for the localized delivery and additional support of MSCs in vivo. In a proof-of-concept study, we assessed the regenerative capacity of cryopreserved MSCs in a full-thickness wound model in mice. The positive impact of MSCs within 3D gel on wound healing rates was confirmed by morphometric and histological examinations. Our results demonstrate the possibility to apply cryopreserved cells immediately after thawing using a cryoprotective medium as the vehicle solution.

Ethics, Evidence Based Sports Medicine, and the Use of Platelet Rich Plasma in the English Premier League

The use of platelet rich plasma (PRP) as a novel treatment is discussed in the context of a qualitative research study comprising 38 interviews with sports medicine practitioners and other stakeholders working within the English Premier League during the 2013-16 seasons. Analysis of the data produced several overarching themes: conservatism versus experimentalism in medical attitudes; therapy perspectives divergence; conflicting versions of appropriate evidence; subcultures; community beliefs/practices; and negotiation of medical decision-making. The contested evidence base for the efficacy of PRP is presented in the context of a broader professional shift towards evidence based medicine within sports medicine. Many of the participants while accepting this shift are still committed to casuistic practices where clinical judgment is flexible and does not recognize a context-free hierarchy of evidentiary standards to ethically justifiable practice. We also discuss a tendency in the data collected to consider the use of deceptive, placebo-like, practices among the clinician participants that challenge dominant understandings of informed consent in medical ethics. We conclude that the complex relation between evidence and ethics requires greater critical scrutiny for this emerging specialism within the medical community.

Cell Therapies in Tendon, Ligament, and Musculoskeletal System Repair

In the last few decades, several techniques have been used to optimize tendon, ligament, and musculoskeletal healing. The evidence in favor of these techniques is still not proven, and level I studies are lacking. We performed an analysis of the therapeutic strategies and tissue engineering projects recently published in this field. Here, we try to give an insight into the current status of cell therapies and the latest techniques of bioengineering applied to the field of orthopedic surgery. The future areas for research in the management of musculoskeletal injuries are outlined. There are emerging technologies developing into substantial clinical treatment options that need to be critically evaluated. Mechanical stimulation of the constructs reproduces a more propitious environment for effective healing.

Biologically Augmented Quadriceps Tendon Autograft With Platelet-Rich Plasma for Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction is one of the most common procedures studied in the orthopaedic literature. In this regard, graft preparation is a key factor for successful outcomes. Although current methods to reconstruct the ACL are generally perceived to be successful, recent studies indicate that normal structure and function of the knee are fully restored in less than half of the patients. Therefore, biologically augmenting these scaffolds could provide a potential solution for improving healing times and biomechanical properties of the graft. The purpose of this Technical Note is to describe our preferred technique for an ACL graft preparation (quadriceps tendon) augmented with platelet-rich plasma.

Effects of platelet-rich plasma in the treatment of plantar fasciitis: A meta-analysis of randomized controlled trials

BACKGROUND

Plantar fasciitis is a common cause of heel pain, which often results in significant morbidity. There have been several treatment options that are used for plantar fasciitis, including nonsteroidal anti-inflammatory drugs, orthoses, physical therapy, and steroid injections.

OBJECTIVES

The aim of this meta-analysis was to compare the effects of platelet-rich plasma (PRP) and other treatments in patients with plantar fasciitis.

SEARCH METHODS

Medline, Web of Science, and Embase were systematically searched to identify relevant trials.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that compared the effects of PRP and other treatments on plantar fasciitis were included.

DATA COLLECTION AND ANALYSIS

The main outcomes included changes from baseline in visual analog scale (VAS) score, American Orthopaedic Foot and Ankle Society Score (AOFAS), and Roles-Maudsley score (RMS). Results were expressed as weight mean difference (WMD) with 95% confidence interval (95% CI). The meta-analysis was performed using a fixed-effects or random-effects model according to heterogeneity.

MAIN RESULTS

Ten RCTs involving a total of 445 patients with plantar fasciitis were included. Among these studies, 9 compared PRP with steroid, and 1 compared PRP with whole blood.Four studies were categorized as being at low risk of bias, and the remaining 6 as being at unclear risk of bias.Pooled estimates suggested that PRP had greater changes in VAS and AOFAS scores than other treatments. However, it had no benefit effect in the RMS.Subgroup analysis for VAS and AOFAS showed that PRP had superior effect than other treatments at 12 months, but not at the 1, 3, 6 months.Subgroup analysis based on treatment regimens demonstrated that PRP was more effective than steroid in the change from baseline in AOFAS, but not in VAS and RMS scores.

AUTHORS' CONCLUSION

PRP was as effective as other treatments in reducing pain and improving function in patients with plantar fasciitis. Subgroup analysis indicated that PRP had better effect than steroid in AOFAS Score and its effect was durable in a long term. However, considering the potential limitations in this study, more large-scale RCTs are needed to confirm the current findings.

Platelet-rich plasma and alignment enhance myogenin via ERK mitogen activated protein kinase signaling

Volumetric muscle loss is debilitating and involves extensive rehabilitation. One approach to accelerate healing, rehabilitation, and muscle function is to repair damaged skeletal muscle using regenerative medicine strategies. In sports medicine and orthopedics, a common clinical approach is to treat minor to severe musculoskeletal injuries with platelet-rich plasma (PRP) injections. While these types of treatments have become commonplace, there are limited data demonstrating their effectiveness. The goal of this study was to determine the effect of PRP on myoblast gene expression and protein production when incorporated into a polymer fiber. To test this, we generated extracellular matrix mimicking scaffolds using aligned polydioxanone (PDO) fibers containing lyophilized PRP (SmartPReP^® 2, Harvest Technologies Corporation, Plymouth, MA). Scaffolds with PRP caused a dose-dependent increase in myogenin and myosin heavy chain but did not affect myogenic differentiation factor-1 (MyoD). Integrin α7β1D decreased and α5β1A did not change in response to PRP scaffolds. ERK inhibition decreased myogenin and increased Myod on the PDO-PRP scaffolds. Taken together, these data suggest that alignment and PRP produce a substrate-dependent, ERK-dependent, and dose-dependent effect on myogenic differentiation.

Non-Transfusional Hemocomponents: From Biology to the Clinic-A Literature Review

Non-transfusional hemocomponents for surgical use are autogenous products prepared through the centrifugation of a blood sample from a patient. Their potential beneficial outcomes include hard and soft tissue regeneration, local hemostasis, and the acceleration of wound healing. Therefore, they are suitable for application in different medical fields as therapeutic options and in surgical practices that require tissue regeneration.

Relationship of cytokine levels and clinical effect on platelet-rich plasma-treated lateral epicondylitis

Lateral epicondylitis (LE) is difficult to manage and can result in significant patient morbidity. Currently, the clinical use of platelet-rich plasma (PRP) for painful tendons has received attention, but its efficacy remains controversial. This study aimed to investigate the clinical effects of PRP and its biological components. A total of 156 patients with LE were randomly divided into group 1, treated with a single injection of 2-ml autologous PRP, and group 2, treated with a control received only physical therapy without injection. Both groups used a tennis elbow strap and performed stretching and strengthening exercises during 24 weeks' follow-up. Pain and functional improvements were assessed using the visual analog scale (VAS), Modified Mayo Clinic Performance Index for the elbow, and magnetic resonance imaging (MRI). White blood cell count, platelet count, and levels of platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, transforming growth factor-β (TGF-β), vascular endothelial growth factor, epithelial growth factor, and interleukin-1 β in PRP were measured and investigated for statistical correlation with the clinical score. At 24 weeks, all pain and functional variables, including VAS score, Mayo Clinic performance scores, and MRI grade, improved significantly in group 1 (p < 0.05). PDGF-AB, PDGF-BB, and TGF-β levels were more significantly increased in PRP than in whole blood. TGF-β level significantly correlated with Mayo Clinic performance score and MRI grade improvement. Thus, TGF-β level in PRP is considered to play a pivotal role in tendon healing. These results may contribute to identifying the best protocol for PRP application in tendinopathies. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:913-920, 2018.

Evaluation of a filter-prepared platelet concentrate for the treatment of suspensory branch injuries in horses

Objectives: Platelet preparations have become a treatment for soft tissue injuries in horses. This study evaluated a novel filter-based system to concentrate platelets and assesses its value in the treatment of suspensory ligament branch desmitis.

Methods: Filtered platelet concentrate was prepared from 55 ml of venous blood obtained from 21 normal horses. Platelets and white blood cells in whole blood and filtered platelet concentrate were measured, as was platelet activating factor (PAF)–induced platelet-derived growth factor-BB (PDGF-BB) release. Eleven horses with 18 focal acute suspensory ligament branch injuries were treated intra-lesionally with autologous filtered platelet concentrate and evaluated clinically and ultrasonographically for one to three years.

Results: The increase in concentration of platelets in the filtered concentrate in comparison with whole blood (6.9 ± 1.9-fold) was significantly greater than the increase in white blood cells (3.8 ± 0.8-fold) (p <0.0001). There was no effect of sex or breed on platelet concentration. Platelets were responsive to PAF with >100-fold higher levels of PDGF release over basal levels. All hypoechoic lesions re-evaluated within three months had resolved. Five of the 11 horses returned to their previous level of work, one was exercising at a lower level, three were retired, one died for unrelated reasons, and one was still convalescing.

Clinical significance: Filtered platelet concentrate was easily and reliably prepared and injected into suspensory ligament branch injuries without short-term complications. This treatment was associated with rapid resolution of ultrasonographic lesions and lameness. Filtered platelet concentrate represents a convenient alternative for the treatment of suspensory ligament branch injuries.

Platelets, inflammation and tissue regeneration

Blood platelets have long been recognised to bring about primary haemostasis with deficiencies in platelet production and function manifesting in bleeding while upregulated function favourises arterial thrombosis. Yet increasing evidence indicates that platelets fulfil a much wider role in health and disease. First, they store and release a wide range of biologically active substances including the panoply of growth factors, chemokines and cytokines released from α-granules. Membrane budding gives rise to microparticles (MPs), another active participant within the blood stream. Platelets are essential for the innate immune response and combat infection (viruses, bacteria, micro-organisms). They help maintain and modulate inflammation and are a major source of pro-inflammatory molecules (e.g. P-selectin, tissue factor, CD40L, metalloproteinases). As well as promoting coagulation, they are active in fibrinolysis; wound healing, angiogenesis and bone formation as well as in maternal tissue and foetal vascular remodelling. Activated platelets and MPs intervene in the propagation of major diseases. They are major players in atherosclerosis and related diseases, pathologies of the central nervous system (Alzheimers disease, multiple sclerosis), cancer and tumour growth. They participate in other tissue-related acquired pathologies such as skin diseases and allergy, rheumatoid arthritis, liver disease; while, paradoxically, autologous platelet-rich plasma and platelet releasate are being used as an aid to promote tissue repair and cellular growth. The above mentioned roles of platelets are now discussed.

Peritendinous injection of platelet-rich plasma to treat tendinopathy: A retrospective review

Objective

The aim of this study was to determine factors associated with the likelihood of a better clinical outcome after the peritendinous injection of PRP for the treatment of chronic tendinopathy and identify whether PRP represents an effective treatment option for chronic tendinopathies.

Methods

The study included 214 patients (86 males and 128 females; mean age: 39.3 (18–75) years) who received PRP injections for tendinopathy refractory to conventional treatments. The mean duration of symptoms at the moment of the PRP treatment was 8.3 months. Primary outcome measurement was perceived improvement in symptoms for each anatomic compartment for upper and lower limbs at 6 months after treatment. Also, a visual analog scale (VAS) score (pain intensity on a 0–10 scale) was used for pain scoring questionnaire before treatment, 6 weeks and 6 months following the PRP injection(s). To identify factors associated with the likelihood of a better clinical outcome, patients were categorized on the basis of their perceived improvement in symptoms 6 months after the PRP injection(s)—that is, as lower (less than 50% global improvement) or higher (more than 50% global improvement).

Results

A visual analogue scale score and perceived improvement in symptoms were significantly lower after peritendinous injection in 6-week and 6-month follow-ups compared with the baseline (P < 0.001) except for peroneal and Achilles tendons. Overall, 83% of patients indicated moderate to complete improvement in symptoms. The most common injection sites were the lateral epicondyle, Achilles, and patellar tendons. Furthermore, 30% of patients received only 1 injection, 30% received 2 injections, and 40% received 3 or more injections. A total of 85% of patients were satisfied (more than 50% global improvement) with the procedure. In addition, upper limb tendons, increase in the age, and female gender were associated with a higher likelihood of perceived improvement in symptoms.

Conclusions

In the present retrospective study assessing PRP injections in the treatment of chronic tendinopathy, a moderate improvement (>50%) in pain symptoms was observed in most of the patients. Our research found that results were most promising with patellar and lateral epicondylar tendinopathy in the short to medium term. Female patients, patients with upper extremity tendinopathy and older patients appeared to benefit more from PRP injection.

Level of evidence

Level IV, Therapeutic study.

Platelet-Rich Plasma for Primary Treatment of Partial Ulnar Collateral Ligament Tears: MRI Correlation With Results

Background:

Jobe revolutionized the treatment of medial ulnar collateral ligament (MUCL) tears with his reconstruction technique. However, not all MUCL injuries require operative management; Rettig showed that 42% of MUCL injuries respond to conservative management. This was improved by Podesta, who showed that augmentation of nonoperative management with platelet-rich plasma (PRP) and magnetic resonance imaging (MRI) for detecting partial MUCL tears resulted in significantly higher success rates. Their series used a single injection of leukocyte-rich PRP. However, to our knowledge, no study has established optimal dosing and composition of PRP for augmentation of soft tissue healing. We present a series of patients with partial MUCL tears of the elbow treated with a series of 2 leukocyte-rich PRP injections, bracing, physical therapy, and a structured return-to-throwing protocol.

Hypothesis:

Nonoperative management of acute or subacute partial MUCL tears of the elbow with a formal treatment protocol will allow the injured ligament to heal without surgery and will permit a rapid return to sport.

Study Design:

Case series; Level of evidence, 4.

Methods:

Patients with symptomatic MUCL instability and magnetic resonance arthrography demonstrating grade 2 MUCL tears at the proximal or distal aspect were treated with varus-loading elbow bracing, activity restriction, and physical therapy, supplemented by 2 injections of PRP. The injections were separated by 2 weeks. Two weeks after the second injection, a repeat examination and magnetic resonance arthrogram were obtained to evaluate the response to treatment.

Results:

A total of 25 athletes (23 baseball athletes, 2 softball athletes [1 participant also danced]) underwent PRP injections and guided rehabilitation. Of these patients, 23 were diagnosed with primary grade 2 injuries of the MUCL; 22 patients with primary injuries (96%) demonstrated stability of the MUCL after treatment and returned to play at the same or higher level of competition without further intervention. Repeat MRI demonstrated reconstitution of the ligament in all patients, although 2 patients demonstrated only partial reconstitution. Patients were released to play at 6 weeks; due to vagaries of sports seasons, the mean time to return to competitive play was 82 days. Two of the 25 patients had undergone prior surgery (1 MUCL reconstruction and 1 repair). These patients remained unstable and symptomatic on examination after this treatment regimen, did not show complete reconstitution of the ligament on subsequent MRI, and required MUCL reconstruction.

Conclusion:

Ouf of 23 primary injury patients who received PRP injections and nonoperative measures, 22 (96%) were able to return to play and demonstrated reconstitution of the MUCL on MRI. Two of the 3 patients for whom PRP therapy failed had undergone previous MUCL surgery. We conclude that a 2-injection regimen of leukocyte-rich PRP is a safe and effective treatment for partial MUCL tears, but it appears to be less effective in patients with previous surgery for MUCL repair or reconstruction.

Platelet rich plasma promotes skeletal muscle cell migration in association with up-regulation of FAK, paxillin, and F-Actin formation

Platelet rich plasma (PRP) contains various cytokines and growth factors which may be beneficial to the healing process of injured muscle. The aim of this study was to investigate the effect and molecular mechanism of PRP on migration of skeletal muscle cells. Skeletal muscle cells intrinsic to Sprague-Dawley rats were treated with PRP. The cell migration was evaluated by transwell filter migration assay and electric cell-substrate impedance sensing. The spreading of cells was evaluated microscopically. The formation of filamentous actin (F-actin) cytoskeleton was assessed by immunofluorescence staining. The protein expressions of paxillin and focal adhesion kinase (FAK) were assessed by Western blot analysis. Transfection of paxillin small-interfering RNA (siRNAs) to muscle cells was performed to validate the role of paxillin in PRP-mediated promotion of cell migration. Dose-dependently PRP promotes migration of and spreading and muscle cells. Protein expressions of paxillin and FAK were up-regulated dose-dependently. F-actin formation was also enhanced by PRP treatment. Furthermore, the knockdown of paxillin expression impaired the effect of PRP to promote cell migration. It was concluded that PRP promoting migration of muscle cells is associated with up-regulation of proteins expression of paxillin and FAK as well as increasing F-actin formation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2506-2512, 2017.