Use of Platelet-Rich Plasma Immediately After an Injury Did Not Improve Ligament Healing, and Increasing Platelet Concentrations Was Detrimental in an In Vivo Animal Model

Lower extremity ultrasound-guided interventions: tendon, ligament, and plantar fascia

Lower extremity tendinopathy and soft tissue injury are common clinical problems that can cause significant disability. Ultrasound-guided minimally invasive treatments using orthobiologics and image-guided percutaneous treatments continue to gain relevance with an ever-growing body of literature. We review the indications, technique, risks, and benefits according to the literature of common ultrasound-guided interventions utilized in the lower extremities.

Molecular and Biologic Effects of Platelet-Rich Plasma (PRP) in Ligament and Tendon Healing and Regeneration: A Systematic Review

Platelet-rich plasma (PRP) has been introduced and applied to a wide spectrum of acute and chronic ligament and tendon pathologic conditions. Although the biological effect of PRP has been studied thoroughly in both animal and human studies, there is no consensus so far on the exact mechanism of its action as well as the optimal timing and dosage of its application. Therefore, we conducted a systematic review aiming to evaluate the molecular effect of the administration of PRP in tendoligamentous injuries and degenerative diseases. The literature search revealed 36 in vitro and in vivo studies examining the healing and remodeling response of animal and human ligament or tendon tissues to PRP. Platelet-rich plasma added in the culture media was highly associated with increased cell proliferation, migration, viability and total collagen production of both ligament- and tendon-derived cells in in vitro studies, which was further confirmed by the upregulation of collagen gene expression. In vivo studies correlated the PRP with higher fibroblastic anabolic activity, including increased cellularity, collagen production and vascularity of ligament tissue. Similarly, greater metabolic response of tenocytes along with the acceleration of the healing process in the setting of a tendon tear were noticed after PRP application, particularly between the third and fourth week after treatment. However, some studies demonstrated that PRP had no or even negative effect on tendon and ligament regeneration. This controversy is mainly related to the variable processes and methodologies of preparation of PRP, necessitating standardized protocols for both investigation and ap-plication.

Leukocyte-Rich Platelet-Rich Plasma Has Better Stimulating Effects on Tenocyte Proliferation Compared With Leukocyte-Poor Platelet-Rich Plasma

Background:

Rotator cuff (RC) tendinopathy is one of the most common causes of shoulder pain. Platelet-rich plasma (PRP) has been frequently used in clinical scenarios, but its efficacy remains inconsistent.

Purpose:

To investigate the different responses of human tenocytes from torn RCs to leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) in a 2-chamber coculture device.

Study Design:

Controlled laboratory study.

Methods:

PRP was prepared using different platelet and leukocyte concentrations according to 5 groups: (1) LR-PRP with 5000 platelets/µL, (2) LR-PRP with 10,000 platelets/µL, (3) LP-PRP with 5000 platelets/µL, (4) LP-PRP with 10,000 platelets/µL, and (5) control with only culture medium supplementation and without PRP stimulation. Platelet-derived growth factor–AB (PDGF-AB) and transforming growth factor–β1 (TGF-β1) were measured in LR-PRP and LP-PRP via enzyme-linked immunosorbent assay. Microscopy, water-soluble tetrazolium salt assay, and quantitative real-time polymerase chain reaction were used to investigate the morphology, proliferation, and gene expression of RC tenocytes exposed to different PRP formulations. Data were collected from at least 3 independent measurements. The results were analyzed via 1-way analysis of variance, followed by the post hoc Bonferroni test.

Results:

The ratio of leukocytes to 5000 platelets/µL was 29.5 times higher in LR-PRP than in LP-PRP (P < .05). In the 5000 platelets/µL groups, the levels of TGF-β1 and PDGF-AB were both significantly higher in LR-PRP versus LP-PRP (TGF-β1: 367.0 ± 16.5 vs 308.6 ± 30.3 pg/mL, respectively [P = .043]; PDGF-AB: 172.1 ± 1.8 vs 94.1 ± 4.2 pg/mL, respectively [P < .001]). Compared with the control group, RC tenocyte proliferation was 1.42 ± 0.01 and 1.41 ± 0.03 times higher in the LR-PRP groups with 5000 platelets/µL and 10,000 platelets/µL, respectively (P < .05). The expression of tenocyte-related genes was higher in tenocytes cultured in LR-PRP.

Conclusion:

Both the LR-PRP groups with 5000 platelets/µL and 10,000 platelets/µL induced more growth factor release and increased RC tenocyte proliferation than did the LP-PRP groups.

Clinical Relevance:

In RC repair, LR-PRP may be better than LP-PRP for increasing the proliferation of tenocytes.

The Efficacy of Platelet-Rich Plasma for Ligament Injuries: A Systematic Review of Basic Science Literature With Protocol Quality Assessment

Background:

Despite the existence of many clinical studies on platelet-rich plasma (PRP) interventions for ligamentous pathology, basic science consensus regarding the indications, mechanisms, and optimal composition of PRP for treating ligament injuries is lacking.

Purpose:

To (1) compare the efficacy of PRP in animal models of ligament injury with placebo and (2) describe the potential variability in PRP preparation using accepted classification systems.

Study Design:

Systematic review.

Methods:

The Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, PubMed, Embase, and Ovid MEDLINE were queried in April 2020 for in vivo and in vitro basic science studies regarding PRP use for ligament injury. Study design, results, PRP composition, and analyzed cellular and molecular markers were extracted, and outcomes relative to control models were documented. Bias was assessed using the SYRCLE risk-of-bias tool.

Results:

Included were 43 articles (31 in vivo and 12 in vitro studies) investigating the anterior cruciate ligament/cranial cruciate ligament (n = 32), medial collateral ligament (n = 6), suspensory ligament (n = 3), patellar ligament (n = 1), and Hock ligament (n = 1). Platelet concentration was reported in 34 studies (77.3%); leukocyte composition, in 12 (27.3%); and red blood cell counts, in 7 (15.9%). With PRP treatment, 5 of 12 in vitro studies demonstrated significant increases in cell viability, 6 of 12 in gene expression, 14 of 32 in vivo studies reported superior ligament repair via histological evaluation, and 13 in vivo studies reported superior mechanical properties. Variability in PRP preparation methods was observed across all articles, and only 1 study reported all necessary information to be classified by the 4 schemes we used to evaluate reporting. Among the in vivo studies, detection and performance bias were consistently high, whereas selection, attrition, reporting, and other biases were consistently low.

Conclusion:

Conflicting data on the cellular and molecular effects of PRP for ligament injuries were observed secondary to the finding that included studies were heterogeneous, limiting interpretation across studies and the ability to draw meaningful conclusions. Clinical trials and any causal relationship between PRP use in ligament injuries and its potential for regeneration and healing should be pursued with caution if based solely on basic science data.

Why might ovarian rejuvenation fail? Decision analysis of variables impacting reproductive response after autologous platelet-rich plasma

Experience with platelet-rich plasma (PRP) has accumulated from use in dental restoration, post-infarct myocardial repair, tendon surgery, pain management, and aesthetic enhancements. Reproductive medicine joined this arena in 2016, beginning with reports of menopause reversal and fertility recovery after autologous PRP for senescent ovaries. Although recent publications have highlighted benefits of 'ovarian rejuvenation', the absence of randomized placebo-controlled clinical trial data has limited its acceptance. Because selection bias tends to underreport negative outcomes, reliable estimates cannot be calculated for how often intraovarian PRP is unsuccessful. Ample information is available, however, to permit an operational root-cause analysis when failures are considered. This assessment uses a PRP treatment care path with a decision theory model to critique pre-intake screening, baseline audit, sample processing, ovarian tissue placement method, equipment selection, and follow-up monitoring. These branched choice points enable interventions likely to determine outcome. Specimen handling for intraovarian PRP merits particular scrutiny, since enormous variation in platelet protocols already exists across unrelated clinical areas. As a new addition to fertility practice, intraovarian PRP requires validation of safety and efficacy to gain wider support. Borrowing PRP knowledge from other domains can facilitate this goal, ideally with appreciation of aspects unique to intraovarian use.

Systematic Review of Platelet-Rich Plasma for Rotator Cuff Repair: Are We Adhering to the Minimum Information for Studies Evaluating Biologics in Orthopaedics?

Background

The therapeutic efficacy of orthobiologic therapies for rotator cuff repair is difficult to evaluate owing to reporting inconsistences. In response, the Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO) guidelines were developed to ensure standard reporting on orthobiologic therapies.

Purpose

To systematically review clinical studies evaluating platelet-rich plasma (PRP) for full-thickness rotator cuff repair and adherence to MIBO guidelines.

Study Design

Scoping review; Level of evidence, 4.

Methods

A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, EMBASE, and the Cochrane Library databases. Inclusion criteria were clinical studies reporting on rotator cuff tears (≥1 cm) surgically repaired with PRP. Patient demographics, biologic intervention, and adherence to the MIBO guidelines were systematically reviewed.

Results

A total of 19 studies (1005 patients) were included in this review. Across all studies, 58.5% of the MIBO checklist items for PRP were reported. Out of 47 checklist items, 19 were reported in over 85% of studies, whereas 22 were reported in less than half of studies. Details of whole-blood processing and characteristics, as well as PRP processing and characteristics, were reported inconsistently, and no study provided adequate information to enable the precise replication of preparation protocols for PRP.

Conclusion

This systematic review highlights the current reporting deficiencies within the scientific literature of important variables for evaluating PRP for full-thickness rotator cuff repair. There was widespread variability among published studies that evaluate PRP for this application and, more specifically, studies were limited by inconsistent universal reporting of whole-blood and PRP processing and postprocessing characteristics. To improve our understanding of biologic efficacy and to promote repeatability, stricter adherence to the MIBO guidelines is necessary. We propose that the checklist limitations be addressed and that modification of the MIBO guidelines be considered to improve the reporting of individual components within certain categories.

Research trends of platelet-rich plasma application in orthopaedics from 2002 to 2020: a bibliometric analysis

BACKGROUND

Platelet-rich plasma (PRP) has been widely used to treat various orthopaedic diseases, and there are a large number of studies on the matter. However, there have been no bibliometric reports on the publications in this field. Bibliometrics is an excellent method to systematically evaluate the current research status of a specific field. In this study, CiteSpace 5.7.R2 software was used to analyse the status, hotspots, and frontiers of PRP in the treatment of orthopaedic diseases in the past 19 years.

METHODS

All articles about the application of PRP in orthopaedics from 2002 to 2020 were searched from the Web of Science Core Collection. The author, country, institution, journal, cited journal, and keywords were retrieved, and the bibliometric analysis was done in CiteSpace 5.7.R2.

RESULTS

A total of 321 articles were retrieved. The analysis showed that the number of publications increased in the past 19 years, and the most productive author in this field was Brian J. Cole. The most productive country and the most productive institution were the US and the Hospital for Special Surgery in New York, respectively. The journals with the highest output and the highest citation frequency were the Journal of Orthopaedic Research and the American Journal of Sports Medicine, respectively. From the keyword analysis, we observed that the primary research hotspots were the study of the PRP composition, growth factors, and the combination of PRP and mesenchymal stem cells. The frontiers of PRP were in vivo experiments, the treatment of rotator cuff and cartilage injury, and the comparison of clinical efficacy between PRP and hyaluronic acid.

CONCLUSION

The efficacy of PRP in treating orthopaedic diseases remains controversial. There are still some problems with the experimental methods, such as insufficient sample size, low level of evidence, confusion of system naming, lack of standardisation of preparation methods and application programs, and lack of in-depth basic scientific research. The research status shown by co-occurrence and cluster maps and the analysis of hotspots and frontiers may help solve present problems and explore new directions.

Has platelet-rich plasma any role in partial tears of the anterior cruciate ligament? Prospective comparative study

BACKGROUND

Partial tears of the anterior cruciate ligament (ACL) are frequent, and there is still considerable controversy surrounding their diagnosis, natural history and treatment.

AIM

To examine patient-reported outcomes, physical examination and magnetic resonance imaging (MRI) findings of partial ACL tears treated with an intraarticular injection of platelet-rich plasma (PRP) compared to a control group.

METHODS

From January 2015 to November 2017, consecutive patients from a single institution with partial ACL tears treated nonoperatively were prospectively evaluated. Partial tears were defined as a positive Lachman test with a clear end-point, a negative pivot-shift and less than 3 mm of side-to-side difference using the KT1000 arthrometer. Patients in group 1 were treated with one intraarticular injection of PRP and specific physical therapy protocol. Control group consisted of patients treated only with physical therapy. Prospective analyzed data included physical examination, Tegner activity level and Lysholm and International Knee Documentation Committee scores. Baseline MRI findings and at 6 mo follow-up were reviewed. Failure was defined as those patients with clinical instability at follow-up that required a subsequent ACL reconstruction.

RESULTS

A total of 40 patients where included, 21 treated with PRP injection with a mean follow-up of 25 mo [standard deviation (SD): 3.6] and 19 in the control group with a mean follow-up of 25 mo (SD: 5.68). Overall failure rate was 32.0% (n = 13). No significant differences were observed between groups regarding subjective outcomes, return to sport and failure rate. MRI findings revealed an improvement in the ACL signal in half of the patients of both groups. However, we did not find a significant relationship between MRI findings and clinical outcomes.

CONCLUSION

Overall, 95.0% of patients returned to sports at a mean follow-up of 25 mo. Mean time to return to sports was 4 mo. Out of these patients, almost 30.0% in each group had a new episode of instability and required surgery at a median time of 5 mo in group 1 and 8 mo in group 2. The addition of PRP alone was not sufficient to enhance any of the outcome measures evaluated, including MRI images, clinical evaluation and failure rate.

Orchestrated cellular, biochemical, and biomechanical optimizations endow platelet-rich plasma-based engineered cartilage with structural and biomechanical recovery

Recently, biomaterials for cartilage regeneration has been intensively investigated. However, the development of scaffolds that capture regenerated cartilage with biomechanical and structural recovery has rarely been reported. To address this challenge, platelet-rich plasma (PRP)-based cartilage constructs with a well-orchestrated symphony of cellular, biochemical and biomechanical elements were prepared by simultaneously employing chondrogenic progenitor cells (CPCs) as a cell source, optimizing platelet concentration, and adding an enzyme-ion activator. It was shown that this triple-optimized PRP + CPC construct possessed increased biomechanical properties and suitable biochemical signals. The following in vitro study demonstrated that the triple-optimized PRP + CPC constructs generated cartilage-like tissue with higher expression levels of chondrogenic-specific markers, more deposition of cartilage-specific extracellular matrix (ECM), and greater biomechanical values than those of the other constructs. Twelve weeks after the construct was implanted in a cartilage defect in vivo, histological analysis, qPCR, and biomechanical tests collectively showed that the triple-optimized constructs yielded a more chondrocyte-like cell phenotype with a higher synthesis of Col-II and aggrecan. More importantly, the triple-optimized constructs facilitated cartilage regeneration with better biomechanical recovery than that of the other constructs. These results demonstrate the efficacy of the triple-optimization strategy and highlight the simplicity and potency of this PRP + CPC construct for cartilage regeneration.

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Cartilage tissue engineering has been intensively investigated.

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We designed a PRP-based construct with favorable cell source, reinforced scaffold and appropriate biofactors.

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This designed construct can facilitate cartilage regeneration with biomechanical and structural recovery simultaneously.

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The favorable performance of the proposed scaffolds highlights the triple-optimization strategy to improve cartilage engineering.

Variation in platelet-rich plasma compositions used for wound healing indications

At present, the role of platelet-rich plasma (PRP) in burn and wound management is undefined. We present some of the evidence for PRP in wound healing and other medical fields. Currently, the high variation in product composition, mode and timing of application prevent a clear definition of the position of PRP in wound healing. Perspectives on solving these issues are described.

Platelet-Rich Plasma Therapy in the Treatment of Diseases Associated with Orthopedic Injuries

Platelet-rich plasma (PRP) is an autologous platelet concentrate prepared from the whole blood that is activated to release growth factors (GFs) and cytokines and has been shown to have the potential capacity to reduce inflammation and improve tissue anabolism for regeneration. The use of PRP provides a potential for repair due to its abundant GFs and cytokines, which are key in initiating and modulating regenerative microenvironments for soft and hard tissues. Among outpatients, orthopedic injuries are common and include bone defects, ligament injury, enthesopathy, musculoskeletal injury, peripheral nerve injury, chronic nonhealing wounds, articular cartilage lesions, and osteoarthritis, which are caused by trauma, sport-related or other types of trauma, or tumor resection. Surgical intervention is often required to treat these injuries. However, for numerous reasons regarding limited regeneration capacity and insufficient blood supply of the defect region, these treatments commonly result in unsatisfactory outcomes, and follow-up treatment is challenging. The aim of the present review is to explore future research in the field of PRP therapy in the treatment of diseases associated with orthopedic injuries. Impact statement In recent years, platelet-rich plasma (PRP) has become widely used in the treatment of diseases associated with orthopedic injuries, and the results of numerous studies are encouraging. Due to diseases associated with orthopedic injuries being common in clinics, as a conservative treatment, more and more doctors and patients are more likely to accept PRP. Importantly, PRP is a biological product of autologous blood that is obtained by a centrifugation procedure to enrich platelets from whole blood, resulting in few complications, such as negligible immunogenicity from an autologous source, and it is also simple to produce through an efficient and cost-effective method in a sterile environment. However, the applicability, advantages, and disadvantages of PRP therapy have not yet been fully elucidated. The aim of the present review is to explore future research in the field of PRP therapy in the treatment of diseases associated with orthopedic injuries, as well as to provide references for clinics.

Preparation Methods and Clinical Outcomes of Platelet-Rich Plasma for Intra-articular Hip Disorders: A Systematic Review and Meta-analysis of Randomized Clinical Trials

Background:

Despite its increasing use in the management of musculoskeletal conditions, questions remain regarding the preparation methods of platelet-rich plasma (PRP) and its clinical applications for intra-articular hip disorders, including femoroacetabular impingement syndrome (FAIS), labral pathology, and osteoarthritis (OA).

Purpose:

To systematically review and assess the preparation methods and clinical outcomes from randomized clinical trials (RCTs) on the use of PRP for intra-articular hip disorders.

Study Design:

Systematic review; Level of evidence, 2.

Methods:

A systematic review in accordance with the 2009 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed in September 2019. The Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, PubMed, Ovid Medline, and Embase were queried for studies regarding the use of PRP to treat intra-articular hip disorders. Qualifying articles were English-language RCTs describing the use of PRP for intra-articular hip disorders, either as standalone treatment or surgical augmentation. Two authors independently assessed article eligibility. Data pertaining to patient characteristics, indication for treatment, PRP preparation method, follow-up period, and clinical outcomes were extracted. Study results were qualitatively reported and quantitatively compared using meta-analysis when appropriate.

Results:

Seven RCTs met inclusion criteria. Four studies described the use of PRP for hip OA and 3 utilized PRP at arthroscopy for FAIS and labral tears. Outcomes after PRP for OA demonstrated improvement in validated patient-reported outcome measures for up to 1 year; however, pooled effect sizes found no statistically significant difference between PRP and hyaluronic acid (HA) regarding pain visual analog scale scores at short-term (≤2 months; P = .27), midterm (4-6 months; P = .85), or long-term (1 year; P = .42) follow-up. When injected at arthroscopy, 1 study reported improved outcomes, 1 reported no difference in outcomes, and 1 reported worse outcomes compared with controls. The meta-analysis demonstrated no statistically significant difference on the modified Harris Hip Score (mHHS) between PRP and control cohorts at a minimum 1-year follow-up. There were considerable deficiencies and heterogeneity in the reporting of PRP preparation methods for both indications.

Conclusion:

Treatment of OA with PRP demonstrated reductions in pain and improved patient-reported outcomes for up to 1 year. However, there was no statistically significant difference between PRP and HA in pain reduction. Likewise, for FAIS and labral surgery there was no statistically significant difference in mHHS outcomes between patients treated with PRP and controls. Given the limited number of studies and variability in PRP preparations, additional high-quality randomized trials are warranted.

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.

Autologous platelet-rich plasma therapy for refractory pain after low-grade medial collateral ligament injury

Objective

This study was performed to explore the effect of intra-articular injection of autologous platelet-rich plasma (PRP) on refractory pain after low-grade medial collateral ligament (MCL) injury.

Methods

In total, 52 patients with refractory pain after low-grade knee MCL injury were treated by intra-articular injection of autologous PRP. Every patient received a 5-mL intra-articular injection of autologous PRP once weekly for 3 weeks. All patients were evaluated by the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form score before treatment and 1, 3, and 6 months after treatment. Magnetic resonance imaging of the knee was performed to observe the healing of the MCL injury 6 months after treatment.

Results

After one injection, the patients’ pain was greatly decreased and they stopped taking nonsteroidal anti-inflammatory drugs. The IKDC Subjective Knee Evaluation Form scores were significantly better after than before treatment; however, there were no significant differences among the various post-treatment time points. Magnetic resonance imaging showed that the low-grade MCL injury had completely healed, and no edema was present around the MCL.

Conclusions

Intra-articular injection of autologous PRP is an effective treatment for refractory pain after low-grade MCL injury.

Nonoperative Treatment of Elbow Ulnar Collateral Ligament Injuries With and Without Platelet-Rich Plasma in Professional Baseball Players: A Comparative and Matched Cohort Analysis

BACKGROUND

Recent studies evaluating nonoperative treatment of elbow ulnar collateral ligament (UCL) injuries augmented with platelet-rich plasma (PRP) have shown promising results. To date, no comparative studies have been performed on professional baseball players who have undergone nonoperative treatment with or without PRP injections for UCL injuries.

HYPOTHESIS

Players who received PRP injections would have better outcomes than those who did not receive PRP.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The Major League Baseball (MLB) Health and Injury Tracking System identified 544 professional baseball players who were treated nonoperatively for elbow UCL injuries between 2011 and 2015. Of these, 133 received PRP injections (PRP group) before starting their nonoperative treatment program, and 411 did not (no-PRP group). Player outcomes and a Kaplan-Meier survival analysis were compared between groups. In addition, to reduce selection bias, a 1:1 matched comparison of the PRP group versus the no-PRP group was performed. Players were matched by age, position, throwing side, and league status: major (MLB) and minor (Minor League Baseball [MiLB]). A single radiologist with extensive experience in magnetic resonance imaging (MRI) interpretation of elbow injuries in elite athletes analyzed 243 MRI scans for which images were accessible for tear location and grade interpretation.

RESULTS

Nonoperative treatment of UCL injuries resulted in an overall 54% rate of return to play (RTP). Players who received PRP had a significantly longer delay in return to throwing (P < .001) and RTP (P = .012). The matched cohort analysis showed that MLB and MiLB pitchers in the no-PRP group had a significantly faster return to throwing (P < .05) and the MiLB pitchers in the no-PRP group had a significantly faster RTP (P = .045). The survival analysis did not reveal significant differences between groups over time. The use of PRP, MRI grade, and tear location were not statistically significant predictors for RTP or progression to surgery.

CONCLUSION

In this retrospective matched comparison of MLB and MiLB pitchers and position players treated nonoperatively for a UCL tear, PRP did not improve RTP outcomes or ligament survivorship, although there was variability with respect to PRP preparations, injection protocols, time from injury to injection, and rehabilitation programs. MRI grade and tear location also did not significantly affect RTP outcomes or progression to surgery.

Editorial Commentary: Platelet-Rich Plasma: The Devil Is in the Details, and the Details Need to Be Better Reported

The use of biologics may be the next big revolution in sports medicine since the use of the arthroscope. However, we are currently in the infancy of both the understanding of biologics in sports medicine and in the methods we are employing to evaluate their efficacy. As surgeons undertake further studies to elucidate the efficacy of platelet-rich plasma in the treatment of a variety of sports medicine pathologies, adherence to minimum guidelines such as the minimum information for studies evaluating biologics in orthopedics will help to clarify the true benefits of platelet-rich plasma and allow colleagues to reproduce these therapies in their respective practices.

Editorial Commentary: Platelet-Rich Plasma for Knee Osteoarthritis: A "Novel" and Effective Symptomatic Approach

Osteoarthritis (OA) constitutes a significant cause of disability, and it is now recognized as a source of increased mortality. Thus, several therapeutic approaches have been reported in the literature in an attempt to mitigate the symptoms of OA with varying degrees of success. Platelet-rich plasma (PRP) is being increasingly accepted as one of the most efficacious approaches for the symptomatic treatment of mild to moderate OA. Several confounding factors can affect the outcome of PRP such as age, grade of OA, PRP processing technique, and number and timing of these injections. However, numerous reports in the literature derived from PRP randomized clinical trials (compared with saline, hyaluronic acid, and other nonsurgical methods) suggest that successful outcomes can be achieved at least at 1-year postinjection with minimal complications.

Platelet-Rich Plasma and the Knee-Applications in Orthopedic Surgery

PURPOSE OF REVIEW

To consolidate and synthesize the most recent evidence on the effects of platelet-rich plasma (PRP) in the knee with respect to osteoarthritis, meniscal injuries, ACL reconstruction, total knee arthroplasty (TKA), and high tibial osteotomy.

RECENT FINDINGS

PRP has been shown to be more beneficial in the context of knee osteoarthritis compared to both placebo and hyaluronic acid. Direct comparison with corticosteroid injections has been sparsely studied. It has also been shown to improve the clinical postoperative course in meniscal injuries and to a lesser extent TKA. Radiographic improvements without clinically significant benefits have been observed with ACL reconstructions treated with PRP. PRP injections may be more beneficial than other current non-surgical management options for specific knee pathologies. Further research should broaden the knowledge of PRP effects on the knee, and identify the type of PRP, growth factor distribution, and route of administration associated with the most benefit.

Editorial Commentary: Hype, Hope and Everything in Between. What Produces the Real Effect for Blood-derived Products Including Platelet-Rich Plasma?

Biological approaches have a promising future in the orthopaedic field because of their potential benefits that include their minimal invasiveness, potential for accelerated healing, and promise for rapid recovery. However, as the initial hype for these therapies starts to fade, it should be replaced by solid basic and clinical science research to tailor each compound to a determined patient/pathology. Blood contains several products that can be both beneficial and detrimental for every specific tissue, and therefore a one-fits-all approach should be avoided. Although beneficial effects have been consistently reported for certain pathologies such as lateral elbow tendinopathy, as an adjunct for rotator cuff repairs and the symptomatic treatment of osteoarthritis, other conditions' outcomes with biologic treatment remain nebulous such as for Achilles tendinopathy. To determine the real effect of these therapies, it is important to maintain strict inclusion criteria in an attempt to isolate the effect of one biologic product that already has many inherent intrinsic variables per se.

Biological Treatment for Osteoarthritis of the Knee: Moving from Bench to Bedside-Current Practical Concepts

Biological-based therapies for cartilage pathology have gained considerable recognition in the last few decades due to their potential benefits including their minimal invasiveness, capacity for unprecedented healing, and potential for rapid recovery. Consequently, these therapies are likely to have the most noteworthy impact on patients with degenerative joint changes who want to remain active. Currently, the most researched treatments include platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and cell-based therapies. Although further basic science research and well-designed randomized clinical trials are needed to elucidate the long-term role of these therapies in the treatment of osteoarthritis, there is compelling evidence for their use for certain indications. This article aims to review the existing literature for biological-based treatment options for osteoarthritis, critically assessing the current evidence-based recommendations and identify potential avenues for development.