The Clinical Use of Platelet-Rich Plasma in Knee Disorders and Surgery-A Systematic Review and Meta-Analysis

Biologic Augmentation of Isolated Meniscal Repair

PURPOSE OF REVIEW

The limited blood supply and intrinsic healing capacity of the meniscus contributes to suboptimal tissue regeneration following injury and surgical repair. Biologic augmentation techniques have been utilized in combination with isolated meniscal repair to improve tissue regeneration. Several innovative strategies such as Platelet-Rich Plasma (PRP), fibrin clots, mesenchymal stem cells (MSCs), bone marrow stimulation, meniscal scaffolds, and meniscal wrapping, are being explored to enhance repair outcomes. This article provides a comprehensive review of recent findings and conclusions regarding biologic augmentation techniques.

RECENT FINDINGS

Studies on PRP reveal mixed outcomes, with some suggesting benefits in reducing failure rates of isolated meniscal repair, while others question its efficacy. Fibrin clots and PRF (Platelet-rich fibrin), although promising, show inconsistent results and lack sufficient evidence for definitive conclusions. MSCs demonstrate potential in preclinical studies, but clinical trials have been limited and inconclusive. Bone marrow stimulation appears effective in certain contexts, but its broader applicability remains uncertain. Meniscal scaffolds, including CMI (Collagen Meniscal Implants) and Actifit (polyurethane scaffolds), show encouraging short- and mid-term outcomes but have not consistently surpassed traditional methods in the long term. Meniscal wrapping is infrequently studied but demonstrates positive short-term results with certain applications. The review reveals a diverse range of outcomes for biologic augmentation in meniscal repair. While certain techniques show promise, particularly in specific scenarios, the overall efficacy of these methods has yet to reach a consensus. The review underscores the necessity for standardized, high-quality research to establish the definitive effectiveness of these biologic augmentation methods.

Utility of Platelet-Rich Plasma Therapy in the Management of Meniscus Injuries: A narrative review

Menisci are crucial for knee joint functions and meniscal tears are common injuries, especially in sports activities. Platelet-rich plasma (PRP), which enhances healing, has emerged as a promising additive treatment for meniscus injuries, utilizing the regenerative properties of platelets and growth factors for improved clinical outcomes. In studies with a follow-up period of less than one year, the use of platelet-rich plasma (PRP) therapy for meniscus injuries showed significant improvements in knee symptoms and daily activity. Patients experienced enhanced outcomes in terms of pain reduction and increased sports activity, with MRI scans indicating stable meniscus conditions after six months. Studies with a follow-up of more than one year, however, did not find significant differences between groups treated with PRP and groups not treated with PRP in terms of various outcome measures, including pain and knee function. The vascularization of the menisci is vital for their proper function, and insufficient blood supply can affect healing of meniscal injuries. PRP therapy is used to enhance meniscal healing by introducing growth factors and anti-inflammatory agents. PRP therapy may enable athletes with meniscal tears to return to sports more quickly and has less rehabilitation duration. While PRP seems promising as an alternative to failed treatment or as an adjunct to treatment in the short term, its long-term effectiveness remains inconclusive. Patient preferences, commitment to therapy rehabilitation, and cost should all be considered on an individual basis.

Current Status and Advancements in Platelet-Rich Plasma Therapy

Platelet-rich plasma (PRP) as a treatment modality has been around for the last four decades, but only truly gained popularity over the last 10 to 15 years in medicine, in a variety of fields ranging from regenerative medicine to infertility treatment. It has gained popularity, especially in treating musculoskeletal conditions where the bulk of research has been performed and published. There is level I evidence available supporting its efficacy in the treatment of osteoarthritis (OA), epicondylitis, bursitis, compressive neuropathy, plantar fasciitis, muscular injuries and osteochondral lesions. Most published research with regards to PRP has been focused on knee OA (limited research in shoulder, elbow, and foot and ankle OA), lateral epicondylitis and carpal tunnel syndrome, whereas spinal and hand conditions have limited research available. Tendinopathies and partial tendon tears have conflicting evidence available, with level I evidence supporting PRP's use in rotator cuff tendinopathies and tears, with contradictory level I evidence discouraging its use in patella and Achilles tendinopathies and tears. The available evidence regarding the use of PRP continues to produce conflicting results, but despite this, there is an ongoing increase in the popularity and use of PRP in patients with musculoskeletal conditions.

Statistical Fragility of Randomized Controlled Trials Evaluating Platelet-Rich Plasma Use for Knee Osteoarthritis: A Systematic Review

Background

Numerous studies have been published on the use of platelet-rich plasma (PRP) for knee osteoarthritis (OA), with conflicting results.

Purpose

To determine the fragility index (FI) and fragility quotient (FQ) of randomized controlled trials (RCTs) that evaluated the use of PRP to treat knee OA.

Study Design

Systematic review.

Methods

RCTs evaluating the efficacy of PRP injections for knee OA from 2000 to 2020 were included for analysis according to PRISMA guidelines. The FI was determined by calculating the number of outcome event reversals required to change the statistical significance. The associated FQ was determined by dividing the FI by the sample size.

Results

Our initial search resulted in 41,149 studies, of which 8 RCTs (678 patients, 72 outcome events) were included in the analysis. One study failed to report PRP formulation details, whereas 87.5% of studies reported using either leukocyte-rich or leukocyte-poor PRP. The platelet concentration was reported in 25% of the included trials. The overall FI of the 72 outcome events was 8.5. Accounting for sample size, the associated FQ was determined to be 0.14, suggesting that the reversal of 14% of outcome events was required to change outcome significance. There were 51 statistically significant outcomes, of which the FI and FQ were 12 and 0.164, respectively.

Conclusion

Comprehensive fragility analysis suggested that the published literature evaluating the efficacy of PRP use for knee OA may lack statistical stability. We recommend the reporting of both an FI and FQ in addition to P value analysis to provide a clear and thorough understanding of the statistical integrity of studies reporting on PRP use for knee OA.

Platelet-Rich Plasma for Knee Osteoarthritis: What Does the Evidence Say?

The utilization of platelet-rich-plasma as a therapeutic intervention for knee osteoarthritis has gained immense attention since 2008. The increase in the number of scientific publications dedicated to this area can be attributed to the majority of favorable results reported in clinical trials and basic science studies. However, despite the growing evidence, the use of platelet-rich plasma in clinical practice still poses controversial aspects. The potential mechanisms of action described for platelet-rich-plasma so far indicate that it could serve as a disease-modifying drug, acting to counteract important aspects of knee osteoarthritis pathophysiology (cartilage breakdown, inflammation, and bone remodeling). Nevertheless, its efficacy in slowing down the progression of knee osteoarthritis remains unproven. While inconsistencies have been noted, the majority of controlled clinical trials and meta-analyses advocate for the utilization of platelet-rich-plasma in treating knee osteoarthritis, as it has demonstrated greater efficacy than hyaluronic acid and placebo, with a follow-up of at least 1 year. Despite advancements made in certain areas, significant diversity persists regarding the formulations used, therapeutic regimen, extended follow-up periods, patient selection, and assessment of clinically relevant outcomes. Consequently, the leading clinical practice guidelines do not recommend its use. In light of the emerging evidence, this narrative review aims to provide an objective evaluation of the recent available scientific literature (last 5 years) focused on randomized clinical trials and meta-analyses to present a current overview of the topic.

Comparison of the clinical effectiveness of activated and non-activated platelet-rich plasma in the treatment of knee osteoarthritis: a systematic review and meta-analysis

INTRODUCTION/OBJECTIVES

Platelet-rich plasma (PRP) has shown to be clinically effective in the treatment of knee osteoarthritis (OA). Notwithstanding, some inconsistences remain due to methodological differences in PRP preparation such as the use (or not) of activation strategies. We aimed to evaluate whether the use of non-activated PRP would be as effective as activated PRP in patients with knee OA.

METHOD

All randomized, placebo-controlled trials were identified through a search in MEDLINE, EMBASE, Scopus, and Web of Science up to June 2022. Pre- and post-injection pain and function scores were collected. The meta-analysis was conducted with a random-effects model and generic inverse variance method. Effect sizes were estimated using standardized mean differences (SMD).

RESULTS

Fourteen clinical trials involving 1292 subjects were included for meta-analysis. Exogenous activation of PRP revealed a significant pain relief (SMD, - 1.05 [95% CI - 1.58 to - 0.52]; p = 0.0001) and a significant functional improvement (SMD, - 1.21 [95% CI - 1.75 to - 0.67]; p < 0.0001) unlike studies describing the use of a non-activated PRP. The sensitivity analysis indicated that the effect size for both outcomes was not influenced by a single study.

CONCLUSIONS

The results of this systematic review suggest that the use of an exogenously activated PRP is more effective in improving both pain and functional scores in patients with knee OA. Key Points • Results from meta-analysis suggest that exogenously activated PRP is clinically more effective than non-activated PRP. • The use of an activated PRP was more frequently reported by the included studies. • The most frequent method for activation was the use of calcium chloride (CaCl₂).

A comprehensive review of intraarticular knee injection therapy, geniculate injections, and peripheral nerve stimulation for knee pain in clinical practice

The knee is the most common joint in adults associated with morbidity. Many pathologies are associated with knee damage, such as gout or rheumathoid arthritis, but the primary condition is osteoarthritis (OA). Not only can osteoarthritis cause significant pain, but it also can result in signficant disability as well. Treatment for this condition varies, starting off with oral analgesics and physical therapy to surgical total knee replacmenet. In the gamut of this various treatments, a conservative approach has included intra articular steroid injections. With time, researchers and clinicians determined that other components injected to the knee may additionally provide relief of this condition. In this investigation, we describe different types of knee injections such as platelet-rich plasma (PRP), hyaluronic acid, stem cells, and prolotherapy. Additionally, we describe the role of geniculate knee injections, radiofrequency, and periopheral nerve stimulation. These treatments should be considered for patients with knee pain refractory to conservative therapies.

Consensus Guidelines on Interventional Therapies for Knee Pain (STEP Guidelines) from the American Society of Pain and Neuroscience

Knee pain is second only to the back as the most commonly reported area of pain in the human body. With an overall prevalence of 46.2%, its impact on disability, lost productivity, and cost on healthcare cannot be overlooked. Due to the pervasiveness of knee pain in the general population, there are no shortages of treatment options available for addressing the symptoms. Ranging from physical therapy and pharmacologic agents to interventional pain procedures to surgical options, practitioners have a wide array of options to choose from – unfortunately, there is no consensus on which treatments are “better” and when they should be offered in comparison to others. While it is generally accepted that less invasive treatments should be offered before more invasive ones, there is a lack of agreement on the order in which the less invasive are to be presented. In an effort to standardize the treatment of this extremely prevalent pathology, the authors present an all-encompassing set of guidelines on the treatment of knee pain based on an extensive literature search and data grading for each of the available alternative that will allow practitioners the ability to compare and contrast each option.

Biological augmentation of meniscal repair: a systematic review

PURPOSE

Orthopedic literature remains divided on the utility of biologic augmentation to optimize outcomes after isolated meniscal repair. The aim of this systematic review is to analyze the clinical outcomes and re-operation rates of biologically augmented meniscal repairs.

METHODS

PubMed, CINAHL, Cochrane, and EMBASE databases were queried in October 2020 for published literature on isolated meniscal repair with biological augmentation. Studies were assessed for quality and risk of bias by two appraisal tools. Patient demographics, meniscal tear characteristics, surgical procedure, augmentation type, post-operative rehabilitation, patient reported outcome measures, and length of follow-up were recorded, reviewed, and analyzed by two independent reviewers.

RESULTS

Of 3794 articles, 18 met inclusion criteria and yielded 537 patients who underwent biologic augmentation of meniscal repair. The biologically augmented repair rates were 5.8-27.0% with PRP augmentation, 0.0-28.5% with fibrin clot augmentation, 0.0-12.9% with marrow stimulation, and 0.0% with stem cell augmentation. One of seven studies showed lower revision rates with augmented meniscal repair compared to standard repair techniques, whereas five of seven found no benefit. Three of ten studies found significant functional improvement of biologically augmented repair versus standard repair techniques and six of ten studies found no difference. There was significant heterogeneity in methods for biologic preparation, delivery, and post-operative rehabilitation protocols.

CONCLUSION

Patients reported significant improvements in functional outcomes scores after repair with biological augmentation, though the benefit over standard repair controls is questionable. Revision rates after biologically augmented meniscal repair also appear similar to standard repair techniques. Clinicians should bear this in mind when considering biologic augmentation in the setting of meniscal repair.

LEVEL OF EVIDENCE

IV.

Role of Platelets in Osteoarthritis-Updated Systematic Review and Meta-Analysis on the Role of Platelet-Rich Plasma in Osteoarthritis

Platelets are an essential component of hemostasis, with an increasing role in host inflammatory processes in injured tissues. The reaction between receptors and vascular endothelial cells results in the recruitment of platelets in the immune response pathway. The aim of the present review is to describe the role of platelets in osteoarthritis. Platelets induce secretion of biological substances, many of which are key players in the inflammatory response in osteoarthritis. Molecules involved in cartilage degeneration, or being markers of inflammation in osteoarthritis, are cytokines, such as tumor necrosis factor α (TNFα), interleukins (IL), type II collagen, aggrecan, and metalloproteinases. Surprisingly, platelets may also be used as a treatment modality for osteoarthritis. Multiple randomized controlled trials included in our systematic review and meta-analyses prove the effectiveness of platelet-rich plasma (PRP) as a minimally invasive method of pain alleviation in osteoarthritis treatment.

Platelet-rich plasma (PRP) augmentation does not result in more favourable outcomes in arthroscopic meniscal repair: a meta-analysis

Background

The efficacy and safety of platelet-rich plasma (PRP) augmentation for arthroscopic meniscal repair is controversial. This meta-analysis compared arthroscopic meniscal repair performed in isolation or augmented with PRP.

Methods

The present study was conducted according to PRISMA 2020 guidelines. Pubmed, Web of Science, Google Scholar and Embase were accessed in August 2021. All the clinical trials which compared arthroscopic meniscal repair performed in isolation or augmented with PRP were included.

Results

Eight hundred thirty-seven patients were included: 38% (318 of 837 patients) were women; the mean age of the patients was 35.6 (range, 20.8–64.3) years; the mean follow-up was 26.2 (range, 6–54) months. Similarity was found in analogue scale (VAS) (P = 0.5) and Lysholm (P = 0.9), and International Knee Documentation Committee (IKDC) scores (P = 0.9). Similarity was found in the rate of failure (P = 0.4) and rate of revision (P = 0.07).

Conclusion

The current published scientific evidence does not support PRP augmentation for arthroscopic meniscal repair.

Editorial Commentary: Intraoperative Platelet-Rich Plasma Injections for Open-Wedge High Tibial Osteotomies Effectively Improve Clinical Outcomes and Minimal Medial Joint Space Width: An Orthobiologic Application

Osteoarthritis is a significant cause of morbidity and mortality involving the knee joint, and high tibial osteotomy is becoming more commonly used to treat severe knee osteoarthritis. In addition, the best management and therapies to mitigate osteoarthritis symptoms and progression may include biologic injections, as we focus on more than just structural abnormalities but also on the inflammatory environment in the joint. These therapies include platelet-rich plasma, bone marrow aspirate concentrate, cell-based therapies, adipose-derived stromal cells, and amniotic suspension allografts. Recent research supports a promising therapy: combined high tibial osteotomy and intraoperative, intraarticular platelet-rich plasma injection.

Application of Stem Cell Therapy for ACL Graft Regeneration

Graft regeneration after anterior cruciate ligament (ACL) reconstruction surgery is a complex three-stage process, which usually takes a long duration and often results in fibrous scar tissue formation that exerts a detrimental impact on the patients' prognosis. Hence, as a regeneration technique, stem cell transplantation has attracted increasing attention. Several different stem cell types have been utilized in animal experiments, and almost all of these have shown good capacity in improving tendon-bone regeneration. Various differentiation inducers have been widely applied together with stem cells to enhance specific lineage differentiation, such as recombinant gene transfection, growth factors, and biomaterials. Among the various different types of stem cells, bone marrow-derived mesenchymal stem cells (BMSCs) have been investigated the most, while ligament stem progenitor cells (LDSCs) have demonstrated the best potential in generating tendon/ligament lineage cells. In the clinic, 4 relevant completed trials have been reported, but only one trial with BMSCs showed improved outcomes, while 5 relevant trials are still in progress. This review describes the process of ACL graft regeneration after implantation and summarizes the current application of stem cells from bench to bedside, as well as discusses future perspectives in this field.

Biologic Therapy in Chronic Pain Management: a Review of the Clinical Data and Future Investigations

PURPOSE

With the aging population, it is clear that the demand for future chronic pain treatment modalities is at an all-time high. One of the newest treatment modalities that is gaining popularity with both practitioners and patients alike is that of regenerative medicine and the use of stem cells to treat chronic painful conditions. This article aims to distill the most recent, available data from both laboratory research and clinical trials to better illuminate the potentials for these therapies in the treatment of chronic pain.

RECENT FINDINGS

There are numerous investigations underway using mesenchymal stem cells (MSCs) to treat painful, largely degenerative conditions. A large majority of these investigations focus on osteoarthritis of the knee and have demonstrated significantly improved pain scores. Some of these investigations have demonstrated significantly increased articular cartilage and meniscus growth as well as improved function. These studies have been smaller (n, 18) and need to be corroborated on a macrolevel. Platelet-rich plasma (PRP)-based therapies have been most extensively studied in the treatment of knee osteoarthritis. Multiple prospective and randomized trials and meta-analyses have afforded level I evidence in support of PRP's safety and efficacy in chronic knee pain demonstrating both decreased pain (via VAS) and increased functional status (via WOMAC and IKDC). There have been randomized controlled trials examining PRP therapies in treatment degenerative disc disease (intradiscal treatment), facet arthropathy (intra-facet injections), and sacroiliitis (SIJ) which have all yielded similar positive results. Each RTC demonstrated decreased pain scores and increased function but lacks the scale to derive concrete guidelines. Newer investigations are underway examining modified PRP formulas with increased fibrin (PRF) or various growth factors (PRGF) and have shown positive outcomes with respect to osteoarthritic conditions in small trials. Animal trials are underway further investigating these therapies as well as specific gene modulation therapies. This review of the most recent investigations into the application and uses of biologic stem cell-derived treatments for chronic painful conditions should act to illustrate the growing, favorable data for these types of modalities both with respect to pain control and functional improvement.

Comprehensive Review of Knee Osteoarthritis Pharmacological Treatment and the Latest Professional Societies' Guidelines

Osteoarthritis is the most common musculoskeletal progressive disease, with the knee as the most commonly affected joint in the human body. While several new medications are still under research, many symptomatic therapy options, such as analgesics (opioid and non-opioid), nonsteroid anti-inflammatory drugs, symptomatic slow-acting drugs in osteoarthritis, and preparations for topical administration, are being used, with a diverse clinical response and inconsistent conclusions across various professional societies guidelines. The concept of pharmacogenomic-guided therapy, which lies on principles of the right medication for the right patient in the right dose at the right time, can significantly increase the patient’s response to symptom relief therapy in knee osteoarthritis. Corticosteroid intra-articular injections and hyaluronic acid injections provoke numerous discussions and disagreements among different guidelines, even though they are currently used in daily clinical practice. Biological options, such as platelet-rich plasma and mesenchymal stem cell injections, have shown good results in the treatment of osteoarthritis symptoms, greatly increasing the patient’s quality of life, especially when combined with other therapeutic options. Non-inclusion of the latter therapies in the guidelines, and their inconsistent stance on numerous therapy options, requires larger and well-designed studies to examine the true effects of these therapies and update the existing guidelines.

Platelet Rich Plasma in Orthopedic Surgical Medicine

There is a global interest in optimizing post-surgical tissue repair strategies, leading to better patient outcomes and fewer complications, most ideally with reduced overall cost. In this regard, in recent years, the interest in autologous biological treatments in orthopedic surgery and sports medicine has increased greatly, and the addition of platelet-rich plasma (PRP) to the surgical armamentarium is of particular note. Unfortunately, the number of PRP preparation devices has also grown immensely over the recent decades, raising meaningful concern for the considerable variation in the qualities of currently available PRP preparations. The lack of consensus on the standardization of PRP preparation and of agreement on condition specific PRP formulations is largely responsible for the sometimes contradictory outcomes in the literature. Furthermore, the full potential of PRP technology, the concept of individualized treatment protocols based on bioformulation options, and platelet dosing, angiogenesis, and antimicrobial and painkilling effects of PRP relevant to orthopedic surgery have rarely been addressed. In this review, we will discuss recent developments regarding PRP preparations and potential therapeutic effects. Additionally, we present a synopsis of several published data regarding PRP applications in orthopedic surgery for treating tendon injuries, inducing bone repair, strengthening spinal fusion outcomes, and supporting major joint replacements.

Accentuating the sources of mesenchymal stem cells as cellular therapy for osteoarthritis knees-a panoramic review

The large economic burden on the global health care systems is due to the increasing number of symptomatic osteoarthritis (OA) knee patients whereby accounting for greater morbidity and impaired functional quality of life. The recent developments and impulses in molecular and regenerative medicine have paved the way for inducing the biological active cells such as stem cells, bioactive materials, and growth factors towards the healing and tissue regenerative process. Mesenchymal stem cells (MSCs) act as a minimally invasive procedure that bridges the gap between pharmacological treatment and surgical treatment for OA. MSCs are the ideal cell-based therapy for treating disorders under a minimally invasive environment in conjunction with cartilage regeneration. Due to the worldwide recognized animal model for such cell-based therapies, global researchers have started using the various sources of MSCs towards cartilage regeneration. However, there is a lacuna in literature on the comparative efficacy and safety of various sources of MSCs in OA of the knee. Hence, the identification of a potential source for therapeutic use in this clinical scenario remains unclear. In this article, we compared the therapeutic effects of various sources of MSCs in terms of efficacy, safety, differentiation potential, durability, accessibility, allogenic preparation and culture expandability to decide the optimal source of MSCs for OA knee.