The Effectiveness of Platelet-Rich Plasma in the Treatment of Tendinopathy: A Meta-analysis of Randomized Controlled Clinical Trials

Interventional Radiology for Rheumatic Diseases

Imaging plays a key role in the management of rheumatological pathologies, also as guidance for diagnostic and therapeutic interventional procedures, as it can provide better accuracy and safety compared to palpation-guided interventions. Inflammatory and degenerative conditions nonresponsive to systemic treatment may benefit from intra-articular and periarticular administration of drugs, with therapeutic and symptomatic actions or providing a bridge for surgery. Desired effects include reduction of inflammation and pain and improvement of physical function of patients. Training and knowledge of indications, appropriate procedures, contraindications, and side effects are necessary to obtain maximum accuracy and safety in performing interventional procedures.

Owner-reported treatments and outcomes of perceived injuries to the thoracic and pelvic limb of agility dogs

Objective

The aim of this study was to identify the type of veterinary care sought by handlers of injured agility dogs, the types of treatments the dogs received, and the timeframe for return to training and competition.

Procedures

Owners of agility dogs completed an internet-based survey. They were instructed to report injuries that had kept the dog from training or competing for over a week, identify which area(s) of the body had been injured and answer questions about the most severe injury to each body part. Additional questions included if handlers had sought veterinary care, who primarily determined treatment, type of treatment(s), and length of time before the dog could return to full training and competition.

Results

This sample included data on 1,714 total injuries from 1,256 unique dogs. Handlers sought veterinary care for over 80% of injuries across all anatomical locations. Handlers were most likely to seek specialty veterinary care for reported injuries to the stifle (71%), iliopsoas (63%) and tibia (61%), and least likely for reported injuries to the carpus (34%), metatarsus (33%) and metacarpus (22%). Treatment of reported injuries to the antebrachium and stifle were most likely to be directed by a veterinarian (>70%), while reported injuries of the thigh (51%) and hip (53%) were least likely. Rest was the most common treatment for all injuries. Return to sport within 3 months was common (>67%) for most perceived injury locations, though dogs with reported stifle injuries took longer to return to competition and had a higher rate of retirement.

Conclusion and clinical relevance

Owners of agility dogs have a high rate of seeking veterinary care for injuries. Overall return to sport rates were high, with the stifle being the notable exception. Future studies regarding specific treatment of injuries in agility dogs, and how injuries and their treatment affect return to agility after injury are required to provide optimal care protocols for these canine athletes.

Comparison of the effects of platelet-rich plasma and platelet-rich fibrin on the healing process of a rat's mucosal wound

Due to the problems associated with the use of PRP, a platelet concentrates without coagulation factors, called platelet-rich fibrin (PRF), has been developed that, in addition to tissue regeneration and wound healing, contains more white blood cells (WBCs), which are important in the wound healing process. In this study, the effect of these two platelet-rich plasmas on the thickness of the epithelium, the number of blood vessels and fibroblasts, and wound area were measured in two groups of PRP and PRF and at different periods. We divided the rats into three groups: the control group, the group receiving PRP, and the group receiving PRF. The results showed a significant difference in the number of fibroblasts, wound area, thickness of epithelium, and number of vessels in all three groups. Based on the results, the use of PRP and PRF in wounds can accelerate the formation of epithelium, create better and more blood vessels, create a platform for the migration and formation of fibroblast cells, and facilitate faster wound closure. Also, comparing PRP and PRF, it can be concluded that, finally, PRF acts better than PRP in epithelialization.

Evaluation of Patellar Tendon Structural Changes following Biological Treatments: Secondary Analysis of Double-Blinded Clinical Trial of Bone Marrow Mesenchymal Stromal Cells and Leukocyte-Poor Platelet-Rich Plasma

Objective quantification of tendon structural changes through imaging is only achieved by evaluating tendon structure using ultrasound tissue characterization (UTC) technology. This study compares the effects of bone marrow mesenchymal stromal cells (BM-MSC) and leukocyte-poor platelet-rich plasma (Lp-PRP) on tendon structure and clinical outcomes in male patients with patellar tendinopathy measured with UTC at 3, 6, and 12 months after treatment. This is a double-blinded clinical trial with a randomized active control study with 20 male patients diagnosed with patellar tendinopathy who underwent BM-MSC and Lp-PRP. Bilateral ultrasound tissue characterization scans of the patellar tendon were carried out after 3, 6, and 12 months, as well as tests for strength and pain. UTC patellar tendon was analyzed at the insertion, proximal, and mid-tendon. BM-MSC showed a greater capacity to promote further positive changes than Lp-PRP. Lp-PRP presented higher disorganized echo-type II in the mid-tendon (p = 0.04; ES = 1.06) and III (p = 0.02; ES = -1.47) after 3 months in the Lp-PRP group. Similar results were seen after 6 and 12 months. Pain and strength data show improvement in the treated tendon. BM-MSC treatment demonstrates a superior capacity to promote tendon regeneration and organization, restore strength, and reduce pain compared to Lp-PRP, after 3, 6, and 12 months in male patients with patellar tendinopathy.

A bibliometric analysis from 2013 to 2023 reveals research hotspots and trends in the connection between sport and regenerative medicine

The field of regenerative medicine for sports injuries has grown significantly in the 21st century. This study attempted to provide an overview of the current state of research and key findings regarding the relationship between sport and regenerative medicine in general, identifying trends and hotspots in research topics. We gathered the literature from the Web of Science (WOS) database covering the last 10 years (2013-2023) pertaining to regenerative medicine for sporter and applied Citespace to assess the knowledge mapping. The findings demonstrated that there were 572, with a faster increase after 2018. The country, institution, and author with the most publications are the USA, Harvard University, and Maffulli Nicola. In addition, the most co-cited reference is J Acad Nutr Diet (2016) (199). Adipose tissue, high tibial osteotomy, and bone marrow are the hot spots in this field in the next few years.

Review of Dohan Eherenfest et al. (2009) on "Classification of platelet concentrates: From pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF)"

This classic discusses the original publication of Dohan Eherenfest et al. on "Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF)", in which the authors propose four categories of platelet concentrates depending on their leucocyte and fibrin content (P-PRP, leucocyte- and platelet-rich plasma (L-PRP), pure platelet-rich fibrin (P-PRF), and L-PRF) to group a "jungle" of products in which the term platelet-rich plasma (PRP) was used indistinctly. They were able to identify common factors such as: (1) the use of anticoagulants and immediate centrifugation of the blood after its collection; (2) most preparation techniques allowed platelet concentrate preparation within an hour; (3) the centrifugation aimed to separate the blood in layers that would allow the extraction of specific fractions; and (4) the product was activated with thrombin or calcium chloride. The reviewed manuscript has been listed among the most cited PRP articles in regenerative medicine, with more than 800 citations, driving current scientific research and clinical practise by categorising L-PRP and P-PRP (now, leucocyte-poor PRP). The classification has also opened the door to understanding intrinsic biological mechanisms between platelets, leukocytes, fibrin, and growth factors, which will later be considered for studying the proliferation and differentiation of cells in different tissues affected by PRP. Since the initial classification of platelet concentrates, several other classification systems have been proposed and published in the current literature such as platelet, activation, white blood cell (PAW), Mishra, platelet, leucocyte, red blood cells, and activation (PLRA), dose of platelet, efficiency, purity, and activation (DEPA), method, activation, red blood cells, spin, platelets, image guidance, leukocytes, and light activation (MARSPILL), etc. These classifications have identified important aspects of PRP that affect the biological composition and, ultimately, the indications and outcomes. To date, there is still a lack of standardisation in sample preparation, cohort heterogeneity, and incomplete reporting of sample preparation utilised, leading to a lack of clarity and challenging researchers and clinicians.

Comparing dry needling or local acupuncture to various wet needling injection types for musculoskeletal pain and disability. A systematic review of randomized clinical trials

PURPOSE

Systematically evaluate the comparative effectiveness of dry needling (DN) or local acupuncture to various types of wet needling (WN) for musculoskeletal pain disorders (MPD).

METHODS

Seven databases (PubMed, PEDro, SPORTDiscus, CINAHL, Scopus, Embase, and Cochrane Central Register of Controlled Trials) were searched following PROSPERO registration. Randomized clinical trials were included if they compared DN or local acupuncture with WN for MPD. Primary outcomes were pain and/or disability. The Revised Cochrane Collaboration tool (RoB 2.0) assessed the risk of bias.

RESULTS

Twenty-six studies were selected. Wet Needling types included cortisone (CSI) (N = 5), platelet-rich plasma (PRP) (N = 6), Botox (BoT) (N = 3), and local anesthetic injection (LAI) (N = 12). Evidence was rated as low to moderate quality. Results indicate DN produces similar effects to CSI in the short-medium term and superior outcomes in the long term. In addition, DN produces similar outcomes compared to PRP in the short and long term and similar outcomes as BoT in the short and medium term; however, LAI produces better pain outcomes in the short term.

CONCLUSION

Evidence suggests the effectiveness of DN to WN injections is variable depending on the injection type, outcome time frame, and diagnosis. In addition, adverse event data were similar but inconsistently reported. PROSPERO Registration: 2019 CRD42019131826Implications for rehabilitationDry needling produces similar effects for pain and disability in the short and medium term compared to cortisone, Botox, and platelet-rich plasma injections. Local anesthetic injection may be more effective at reducing short-term pain.Long-term effects on pain and disability are similar between dry needling and platelet-rich plasma injections, but dry needling may produce better long-term outcomes than cortisone injections.The available adverse event data is similar between dry and wet needling.The conclusions from this study may be beneficial for patients and clinicians for considering risk and cost benefit analyses.

Advances with Platelet-Rich Plasma for Bone Healing

Despite significant advances in the understanding and delivery of osteosynthesis, fracture non-union remains a challenging clinical problem in orthopaedic surgery. To bridge the gap, basic science characterization of fracture healing provides a platform to identify and target biological strategies to enhance fracture healing. Of immense interest, Platelet-rich plasma (PRP) is a point of care orthobiologic that has been extensively studied in bone and soft tissue healing given its relative ease of translation from the benchtop to the clinic. The aim of this narrative review is to describe and relate pre-clinical in-vitro and in-vivo findings to clinical observations investigating the efficacy of PRP to enhance bone healing for primary fracture management and non-union treatment. A particular emphasis is placed on the heterogeneity of PRP preparation techniques, composition, activation strategies, and delivery. In the context of existing data, the routine use of PRP to enhance primary fracture healing and non-union management cannot be supported. However, it is acknowledged that extensive heterogeneity of PRP treatments in clinical studies adds obscurity; ultimately, refinement (and consensus) of PRP treatments for specific clinical indications, including repetition studies are warranted.

Clinical and Biochemical Implications of Hyaluronic Acid in Musculoskeletal Rehabilitation: A Comprehensive Review

Hyaluronic acid (HA) naturally occurs as a biopolymer in the human body, primarily in connective tissues like joints and skin. Functioning as a vital element of synovial fluid, it lubricates joints, facilitating fluid movement and diminishing bone friction to protect articular well-being. Its distinctive attributes encompass notable viscosity and water retention capacities, ensuring flexibility and absorbing shock during motion. Furthermore, HA has gained significant attention for its potential benefits in various medical applications, including rehabilitation. Ongoing research explores its properties and functions, especially its biomedical applications in several clinical trials, with a focus on its role in improving rehabilitation outcomes. But the clinical and biochemical implications of HA in musculoskeletal rehabilitation have yet to be fully explored. This review thoroughly investigates the properties and functions of HA while highlighting its biomedical applications in different clinical trials, with a special emphasis on its role in rehabilitation. The presented findings provide evidence that HA, as a natural substance, enhances the outcomes of musculoskeletal rehabilitation through its exceptional mechanical and biochemical effects.

Platelet-rich plasma injections as a treatment for Achilles tendinopathy and plantar fasciitis in athletes

Platelet-rich plasma (PRP) injections represent a growing interest in the use of biologic therapies for treatment of musculoskeletal injuries. One possible application of PRP is in the management of overuse injuries commonly experienced by athletes. The aim of this review is to evaluate and summarize existing evidence regarding the efficacy of PRP in the treatment of Achilles tendinopathy and plantar fasciitis in athletes. Although many lower quality single-armed studies have demonstrated clinical improvement in athletes treated for Achilles tendinopathy with PRP, higher quality randomized controlled trials (RCTs) have shown no clear benefit in athletes. Existing data suggest PRP significantly improves clinical outcomes for plantar fasciitis in the general population, but very few studies and no RCTs are available that specifically analyze outcomes in athletic populations. More research is needed to evaluate how platelet concentration, leukocyte and erythrocyte presence, and sport type may interact to affect clinical outcomes in athletes.

Bevacizumab promotes tenogenic differentiation and maturation of rat tendon-derived cells in vitro

Previous work suggested that tenogenic differentiation of tendon stem/progenitor cells (TSPCs) was suppressed by upregulated expression of the angiogenic marker vascular endothelial growth factor (VEGF). The purpose of this study was to test the hypothesis that anti-VEGF antibody, bevacizumab, promotes in vitro tenogenic differentiation and maturation of two distinct types of TSPCs, tendon proper-derived cells (TDCs), and paratenon-derived cells (PDCs) originating from rat Achilles tendon. TDCs and PDCs were isolated from the tendon proper and the paratenon of rat Achilles tendons. TDCs and PDCs were cultured for 3 days on plates with or without VEGF. TDCs and PDCs were also cultured in collagen gel matrix, and the blocking effect of VEGF was examined by the addition of 100 ng/mL of bevacizumab. Effects of bevacizumab on tenogenic differentiation were assessed using real-time PCR, immunofluorescent staining, and western blotting. VEGF significantly attenuated expression of the Tnmd gene in both PDCs and TDCs (P<0.05). Expressions of the Scx, Tnmd, and Col1a1 genes were significantly upregulated by the addition of bevacizumab (P<0.05). Immunofluorescent staining showed that the percentage of tenomodulin-positive PDCs and TDCs was significantly higher with bevacizumab treatment than in control cultures (P<0.05). Western blotting showed that bevacizumab suppressed pVEGFR-2 protein expression in both PDCs and TDCs. Bevacizumab promoted the in vitro tenogenic differentiation and maturation of two distinct TSPCs derived from rat Achilles tendon. Since the previous studies demonstrated that TSPCs have a potential to contribute to tendon repair, attenuating VEGF levels in TSPCs by administration of bevacizumab is a novel candidate therapeutic option for promoting tendon repair.

Percutaneous ultrasound-guided needle tenotomy for treatment of chronic tendinopathy and fasciopathy: a meta-analysis

OBJECTIVES

To systematically assess the efficacy of percutaneous ultrasound-guided needle tenotomy (PUNT) in the treatment of chronic tendinopathy and fasciopathy.

METHODS

A comprehensive literature search was performed with the following search terms: tendinopathy, tenotomy, needling, Tenex, fasciotomy, ultrasound-guided, and percutaneous. Inclusion criteria consisted of original studies evaluating pain or function improvement after PUNT. Meta-analyses investigating standard mean differences were performed to assess the pain and function improvement.

RESULTS

Thirty-five studies with 1674 participants (1876 tendons) were enrolled in this article. Of which 29 articles were included in meta-analysis and the remaining 9 articles without enough numeric data were included in descriptive analysis. PUNT significantly alleviated pain with the standard mean difference of 2.5 (95% CI: 2.0-3.0; p < 0.05), 2.2 (95% confidence interval (CI): 1.8-2.7; p < 0.05), and 3.6 (95% CI: 2.8-4.5; p < 0.05) points in short-term, intermediate-term, and long-term follow-up intervals, respectively. It was also associated with marked improvement in function with 1.4 (95% CI: 1.1-1.8; p < 0.05), 1.8 (95% CI: 1.3-2.2; p < 0.05), and 2.1 (95% CI: 1.6-2.6; p < 0.05) points, respectively in short-term, intermediate-term, and long-term follow-ups.

CONCLUSION

PUNT improved pain and function at short-term intervals with persistent results on intermediate- and long-term follow-ups. PUNT can be considered an appropriate minimally invasive treatment for chronic tendinopathy with a low rate of complications and failures.

CLINICAL RELEVANCE

Tendinopathy and fasciopathy are two common musculoskeletal complaints that can cause prolonged pain and disability. PUNT as a treatment option could improve pain intensity and function.

KEY POINTS

• The best improvement in pain and function was achieved after the first 3 months following PUNT and was continued to the intermediate- and long-term follow-ups. • No significant difference was found between different tenotomy methods in terms of pain and function improvement. • PUNT is a minimally invasive procedure with promising results and low complication rates for treatments of chronic tendinopathy.

Hip Pain in an Athlete

ABSTRACT

Hip pain is a common complaint in sports, and narrowing the differential diagnosis can be difficult. Many etiologies are secondary to overuse and respond well to nonsurgical treatment. The increased use of point-of-care ultrasound has helped provide timely and accurate diagnoses and some guided treatments. The hip is in close proximity to the abdomen and pelvis, and clinicians should be familiar with nonmusculoskeletal pain generators. This article is a comprehensive review of hip pain etiologies in athletes.

Safety and Efficacy of Bone Marrow-Derived Mesenchymal Stem Cells for Chronic Patellar Tendinopathy (With Gap >3 mm) in Patients: 12-Month Follow-up Results of a Phase 1/2 Clinical Trial

Background

In a previous study, the authors found that at 6 months after treatment with a 20 × 106 dose of bone marrow-derived mesenchymal stem cells (BM-MSCs), patients showed improved tendon structure and regeneration of the gap area when compared with treatment using leukocyte-poor platelet-rich plasma (Lp-PRP). The Lp-PRP group (n = 10), which had not seen tendon regeneration at the 6-month follow-up, was subsequently offered treatment with BM-MSCs to see if structural changes would occur. In addition, the 12-month follow-up outcomes of the original BM-MSC group (n = 10) were evaluated.

Purpose

To evaluate the outcomes of all patients (n = 20) at 12 months after BM-MSC treatment and observe if the Lp-PRP pretreated group experienced any type of advantage.

Study Design

Cohort study; Level of evidence, 2.

Methods

Both the BM-MSC and original Lp-PRP groups were assessed at 12 months after BM-MSC treatment with clinical examination, the visual analog scale (VAS) for pain during daily activities and sports activities, the Victorian Institute of Sport Assessment-Patella score for patellar tendinopathy, dynamometry, and magnetic resonance imaging (MRI). Differences between the 2 groups were compared with the Student t test.

Results

The 10 patients originally treated with BM-MSCs continued to show improvement in tendon structure in their MRI scans (P < .0001), as well as in the clinical assessment of their pain by means of scales (P < .05). Ten patients who were originally treated with Lp-PRP and then with BM-MSCs exhibited an improvement in tendon structure in their MRI scans, as well as a clinical pain improvement, but this was not significant on the VAS for sports (P = .139). Thus, applying Lp-PRP before BM-MScs did not yield any type of advantage.

Conclusion

The 12-month follow-up outcomes after both groups of patients (n = 20) received BM-MSC treatment indicated that biological treatment was safe, there were no adverse effects, and the participants showed a highly statistically significant clinical improvement (P < .0002), as well as an improvement in tendon structure on MRI (P < .0001). Preinjection of Lp-PRP yielded no advantages.

Comparison of Clinical Outcomes after Platelet-Rich Plasma and Rotator Cuff Repair in High-Grade Intrasubstance Partial Rotator Cuff Tears

Platelet-rich plasma injections have been shown to have many useful applications in various musculoskeletal pathologies. Research on the use of PRP for intrasubstance partial-thickness rotator cuff tears is lacking, although these tears have unique properties that may increase the efficacy of platelet-rich plasma injections. Patients with MRI-confirmed high-grade intrasubstance partial-thickness rotator cuff tears, that had failed traditional non-operative treatment, were offered either surgical repair (Group 1) or a single ultrasound-guided platelet-rich plasma injection into the tear site (Group 2). Patients were followed at 2 weeks, 6 weeks, 3 months, and a minimum of 2 years post-injection with ASES scores. A total of 25 patients received platelet-rich plasma injections, compared to 20 patients who had rotator cuff repair for intrasubstance tears in the last 3 years. The mean pre-injection ASES score for the platelet-rich plasma group was 53.2 and this improved to 92.9 at a minimum 2-year follow-up. The average convalescence period following platelet-rich plasma injection was 3.3 months. The average post-operative convalescence period for arthroscopic rotator cuff repair was 4.6 months. Both surgical repair and platelet-rich plasma injection into the tear site are equally effective in the treatment of high-grade intrasubstance partial-thickness rotator cuff tears, while platelet-rich plasma provides significantly shorter recovery time.

Safety and efficacy of intra-articular injection of platelet-rich plasma for the treatment of ankle osteoarthritis: a systematic review and meta-analysis

PURPOSE

To evaluate the safety and efficacy of platelet-rich plasma (PRP) intra-articular injective treatments for ankle osteoarthritis (OA).

METHODS

A systematic literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in PubMed, Scopus, Embase, Google Scholar, and the Cochrane library until May 2022. Both randomized and non-randomized studies were included with the assessment of the risk of bias. We recorded the participant's age, gender, type of PRP, injection volume, the kit used, and activating agent. We subsequently assessed the short-term and long-term efficacy of PRP using the functional scores and visual analog scale (VAS).

RESULTS

We included four studies with a total of 127 patients, with a mean age of 56.1 years. 47.2% were male (60/127), according to eligibility criteria. There were three cohort studies and one randomized controlled trial (RCT) study, and no study reported severe adverse events. All included studies used the Leukocyte-poor PRP. Short-term follow-up results suggested significant improvement of the American Orthopaedic Foot and Ankle Society (AOFAS) score in the PRP injection group compared to the control group (n = 87 patients; MD: 6.94 [95% CI: 3.59, 10.29]; P < 0.01). Consistently, there was a statistical difference in AOFAS score between PRP injection and control groups in the final follow-up (≥ 6 months) (n = 87 patients; MD: 9.63 [95% CI: 6.31, 12.94]; P < 0.01). Furthermore, we found a significant reduction in VAS scores in the PRP groups at both the short-term follow-up (n = 59 patients; MD, - 1.90 [95% CI, - 2.54, - 1.26]; P < 0.01) and the ≥ six months follow-up (n = 79 patients; MD, - 3.07 [95% CI, - 5.08, - 1.05]; P < 0.01). The improvement of AOFAS and VAS scores at ≥ six months follow-up reached the minimal clinically important difference (MCID). Nevertheless, the treatment effect of AOFAS and VAS scores offered by PRP at short-term follow-up did not exceed the MCID. Substantial heterogeneity was reported at the ≥ six months follow-up in VAS scores (I2: 93%, P < 0.01).

CONCLUSION

This meta-analysis supports the safety of PRP intra-articular injection for ankle OA. The improvements of AOFAS and VAS scores in the PRP group at short-term follow-up do not exceed the MCID to be clinically significant. PRP injection provides significant improvement of AOFAS score and reduced pain at ≥ six months follow-up. The efficacy of PRP should be interpreted with caution regarding the high heterogeneity and the scarcity of available literature, which urges large-scale RCTs with longer follow-up to confirm the potential efficacy of PRP injection for ankle OA.

Current Concepts in Patellar Tendinopathy: An Overview of Imaging, Pathogenesis, and Nonoperative and Operative Management

» Approximately 1 in 3 high-impact athletes develops patellar tendinopathy (PT), with the proximal insertion of the patellar tendon being the most commonly affected anatomical site.» Nonoperative treatment options are effective in reducing pain and restoring functionality in most patients with PT. However, operative intervention should be considered when conservative management fails.» A comprehensive review of the literature on surgical procedures, including both open and arthroscopic approaches, was conducted with a specific focus on clinical outcomes and return to sports.» Both open surgery and arthroscopic surgery for PT have demonstrated favorable success rates and return-to-sport outcomes, with arthroscopic treatment potentially expediting the recovery process.

Platelet-rich plasma in the pathologic processes of tendinopathy: a review of basic science studies

Tendinopathy is a medical condition that includes a spectrum of inflammatory and degenerative tendon changes caused by traumatic or overuse injuries. The pathological mechanism of tendinopathy has not been well defined, and no ideal treatment is currently available. Platelet-rich plasma (PRP) is an autologous whole blood derivative containing a variety of cytokines and other protein components. Various basic studies have found that PRP has the therapeutic potential to promote cell proliferation and differentiation, regulate angiogenesis, increase extracellular matrix synthesis, and modulate inflammation in degenerative tendons. Therefore, PRP has been widely used as a promising therapeutic agent for tendinopathy. However, controversies exist over the optimal treatment regimen and efficacy of PRP for tendinopathy. This review focuses on the specific molecular and cellular mechanisms by which PRP manipulates tendon healing to better understand how PRP affects tendinopathy and explore the reason for the differences in clinical trial outcomes. This article has also pointed out the future direction of basic research and clinical application of PRP in the treatment of tendinopathy, which will play a guiding role in the design of PRP treatment protocols for tendinopathy.

Role of platelet-rich plasma in the treatment of rotator cuff tendinopathy

Shoulder pain is a common musculoskeletal complaint, and rotator cuff (RC) pathologies are one of the main causes. The RC undergoes various tendinopathic and avascular changes during the aging process. Other degenerative changes affecting its healing potential make it an appealing target for biological agents. Platelet-rich plasma (PRP) has demonstrated the potential to deliver a high concentration of several growth factors and anti-inflammatory mediators, and its clinical use is mainly supported by experiments that demonstrated its positive effect on muscle, ligaments, and tendinous cells. This review aimed to specify the role of PRP and its future applications in RC tendinopathies based on the current clinical evidence. Due to the different characteristics and conflicting outcomes, clinicians should use PRP with moderate expectations until more consistent evidence is available. However, it is reasonable to consider PRP in patients with contraindications to corticosteroid injections or those with risk factors for inadequate healing. Its autologous origin makes it a safe treatment, and its characteristics make it a promising option for treating RC tendinopathy, but the efficacy has yet to be established.

3D-printed hydrogel particles containing PRP laden with TDSCs promote tendon repair in a rat model of tendinopathy

Long-term chronic inflammation after Achilles tendon injury is critical for tendinopathy. Platelet-rich plasma (PRP) injection, which is a common method for treating tendinopathy, has positive effects on tendon repair. In addition, tendon-derived stem cells (TDSCs), which are stem cells located in tendons, play a major role in maintaining tissue homeostasis and postinjury repair. In this study, injectable gelatine methacryloyl (GelMA) microparticles containing PRP laden with TDSCs (PRP-TDSC-GM) were prepared by a projection-based 3D bioprinting technique. Our results showed that PRP-TDSC-GM could promote tendon differentiation in TDSCs and reduce the inflammatory response by downregulating the PI3K-AKT pathway, thus promoting the structural and functional repair of tendons in vivo.

Therapeutic Potential of Exosomes in Tendon and Tendon-Bone Healing: A Systematic Review of Preclinical Studies

Exosomes have been proven to play a positive role in tendon and tendon-bone healing. Here, we systematically review the literature to evaluate the efficacy of exosomes in tendon and tendon-bone healing. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic and comprehensive review of the literature was performed on 21 January 2023. The electronic databases searched included Medline (through PubMed), Web of Science, Embase, Scopus, Cochrane Library and Ovid. In the end, a total of 1794 articles were systematically reviewed. Furthermore, a "snowball" search was also carried out. Finally, forty-six studies were included for analysis, with the total sample size being 1481 rats, 416 mice, 330 rabbits, 48 dogs, and 12 sheep. In these studies, exosomes promoted tendon and tendon-bone healing and displayed improved histological, biomechanical and morphological outcomes. Some studies also suggested the mechanism of exosomes in promoting tendon and tendon-bone healing, mainly through the following aspects: (1) suppressing inflammatory response and regulating macrophage polarization; (2) regulating gene expression, reshaping cell microenvironment and reconstructing extracellular matrix; (3) promoting angiogenesis. The risk of bias in the included studies was low on the whole. This systematic review provides evidence of the positive effect of exosomes on tendon and tendon-bone healing in preclinical studies. The unclear-to-low risk of bias highlights the significance of standardization of outcome reporting. It should be noted that the most suitable source, isolation methods, concentration and administration frequency of exosomes are still unknown. Additionally, few studies have used large animals as subjects. Further studies may be required on comparing the safety and efficacy of different treatment parameters in large animal models, which would be conducive to the design of clinical trials.

The effectiveness of percutaneous ultrasound-guided needle tenotomy compared to alternative treatments for chronic tendinopathy: a systematic review

OBJECTIVES

To compare percutaneous ultrasound-guided needle tenotomy (PUNT) to alternative treatments for chronic tendinopathy.

MATERIALS AND METHODS

A systematic literature search was performed with the following combination of keywords: ultrasound-guided, percutaneous, needling, tenotomy, Tenex, tendinopathy, and fasciotomy. Original studies comparing PUNT to alternative treatments for chronic tendinopathy were included in this systematic review.

RESULTS

Twelve (n = 12) studies with 481 subjects were included. Two (2/12) articles compared PUNT to surgical tenotomy and concluded that PUNT provides the same outcomes as surgical tenotomy. Six (6/12) studies compared PUNT to platelet-rich plasma (PRP) injections, and two of them found both treatment modalities effective with no significant between-group differences. Three trials claimed that PUNT followed by PRP injections showed superior clinical outcomes compared to PUNT alone. However, the difference at long-term follow-up was statistically significant only in one of them. One study found PUNT superior to PUNT + PRP injection at short-term follow-up, although there were no between-group differences at long-term follow-up. Four (4/12) studies compared PUNT to steroid injection (SI) and showed that SI causes fast (2 weeks) but temporary pain relief, PUNT results in persistent but relatively slower improvement to SI, and the combined procedure has a more rapid and steady reduction in symptoms.

CONCLUSION

PUNT is an effective treatment technique for chronic tendinopathy and should be considered when non-invasive treatments have failed. Effects of PRP and SI are transient and dissipate over time and do not contribute to long-term outcome.

Orthobiologics: Current Status in 2023 and Future Outlook

Orthobiologic agents, including platelet-rich plasma, connective tissue progenitor cells derived from bone marrow, adipose, and other tissues, and purified cytokines and small peptides, have tremendous potential to target deficiencies in soft-tissue healing. The principal limitation currently is the variability in the composition and biologic activity of orthobiologic formulations, making it difficult to choose the optimal treatment for a specific tissue or pathology. Current data suggest that orthobiologics are "symptom-modifying," but there is little evidence that they can lead to true tissue regeneration ("structure-modifying"). A critically important need at this time is to identify sentinel markers of potency and biologic activity for different orthobiologic formulations so that we can match the treatment to the desired biologic effect for a specific tissue or pathology. Improved understanding of the underlying cellular and molecular mechanisms of tissue degeneration and repair will allow a precision medicine approach where we can choose the optimal orthobiologic treatment of specific orthopaedic problems. It is important for the clinician to be aware of the evolving regulatory status of orthobiologic treatments. Emerging therapies such as the use of exosomes and gene therapy approaches hold great promise as improved methods to both treat symptoms and affect tissue regeneration.

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

Background

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

Methods

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

Results

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

Conclusion

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

Effects of Platelet-Rich Plasma in Tear Size Reduction in Partial-Thickness Tear of the Supraspinatus Tendon Compared to Corticosteroids Injection

OBJECTIVES

Corticosteroid (CS) injection is commonly used in partial-thickness rotator cuff tears to decrease pain. However, this could result in unwanted side effects, such as tendon rupture. Alternatively, platelet-rich plasma (PRP) injection is frequently used to treat tendinopathies because it enhances healing. This study aimed to compare the differences in tear size and functional scores between intralesional PRP and subacromial CS injections.

METHODS

Patients with symptomatic partial-thickness tears of the supraspinatus tendon who underwent conservative treatment for ≥ 3 months were enrolled. All patients underwent magnetic resonance imaging (MRI) to confirm the diagnosis. Fourteen and 15 patients were randomized to receive intralesional PRP and subacromial CS injections, respectively. Tears were measured in the coronal and sagittal planes. The patients underwent another MRI 6 months after the injection. Tear size was compared between the two MRI results. The American Shoulder and Elbow Surgeons Shoulder score (ASES) and Constant-Murley score (CMS) were also obtained.

RESULTS

The baseline data were similar between the groups. In the coronal plane, PRP and CS showed tear size reductions of 3.39 mm (P = 0.003) and 1.10 mm (P = 0.18), respectively. In the sagittal plane, PRP and CS showed tear size reductions of 2.97 mm (P = 0.001) and 0.76 mm (P = 0.29), respectively. Functional scores improved 6 months after injection in both groups, but PRP showed better functional scores than CS (P = 0.002 for ASES, P = 0.02 for CS).

CONCLUSION

Intralesional PRP injection can reduce the tear size in partial-thickness tears of the supraspinatus tendon. Subacromial steroid injection did not significantly affect the tear size. While CS improved functional scores compared with baseline, PRP resulted in better improvement 6 months post-injection. Trial registration Thai Clinical Trials Registry, TCTR20210428004. Registered 28 April 2021-retrospectively registered, TCTR20210428004 .

Japanese Laws and the Current Status of Regenerative Medicine in the Tohoku Region

AIM

The aim of this study was to review Japanese laws regarding regenerative medicine and the current status of clinical application of regenerative medicine, to learn about the advantages and problems, and to thereby serve as a reference for measures necessary for the development of regenerative medicine.

BACKGROUND

Regenerative medicine started in 1957 with the transplantation of hematopoietic stem cells, followed by the establishment of embryonic stem cells in 1981 and induced pluripotent stem cells in 2006, and continues to evolve progressively. At the same time, however, problems have emerged due to lax legal regulations, such as the use of treatments that lack scientific evidence.

REVIEW RESULTS

The Japanese government enacted two laws to regulate regenerative medicine: the Law to Ensure the Safety of Regenerative Medicine and the Amend the Pharmaceutical Affairs Law in 2013. These laws were enacted with the aim of providing safe regenerative medicine promptly and smoothly and developing many regenerative medicine products. In these laws, regenerative medicine is defined as medical treatment that restores lost functions of damaged organs and tissues with the help of cellular and tissue-based products. Nowadays, there are two major methods of regenerative medicine. One representative method involves the transplantation of devices that activates self-regenerative ability by introducing living cells into patients' body. The other method is the activation and differentiation of endogenous stem cells with cell growth and differentiation factors.

CONCLUSION

The current status of regenerative medicine in the Tohoku region after the enactment of these laws is described in detail. This clarified the advantages and disadvantages associated with regenerative medicine as it is currently practiced in Japan.

CLINICAL SIGNIFICANCE

Development of regenerative medicine in dentistry will be advanced by learning about its clinical application in medicine.

Advances in the Clinical Application of Platelet-Rich Plasma in the Foot and Ankle: A Review

Autologous and recombinant biologic substances have been generated as a result of the research into the cellular features of the healing process. Orthobiologics are increasingly being used in sports medicine and musculoskeletal surgery. Nevertheless, clinical data are limited; consequently, further studies are required, particularly in foot and ankle pathologies. This review aims to provide evidence of the most recent literature results and ignite the interest of orthopedic specialists eager for an update about the most current discussion on platelet-rich plasma (PRP) clinical applications in the foot and ankle fields. Previous studies have shown that platelet-rich plasma can be beneficial in treating various conditions, such as chronic foot ulcers, osteoarthritis, Achilles tendinopathy, etc. Despite the positive effects of PRP on various musculoskeletal conditions, more prospective studies are needed to confirm its effectiveness at treating ankle and foot pathologies. In addition to clinical trials, other factors, such as the quality of the research and the procedures involved, must be considered before they can be used in patients. More long-term evaluations are needed to support or oppose its application in treating foot and ankle disorders. We present the most extensive review of PRP's clinical applications in the foot and ankle field.

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.

Platelet-Rich Plasma Injections Decrease the Need for Any Surgical Procedure for Chronic Epicondylitis versus Conservative Treatment-A Comparative Study with Long-Term Follow-Up

Background: Platelet-rich plasma (PRP) injections may alleviate symptoms of chronic medial or lateral epicondylitis. Methods: We retrospectively analyzed a total of 55 patients with chronic ME or LE who had undergone at least 6 months of any conservative treatment before intervention. The patients were divided into two groups: the PRP group (n = 25), who received a single injection of autologous PRP to the medial or lateral epicondyle, and the PT group (n = 30), who continued with PT and pain medication. The primary outcome measures were pain and functional outcomes measured in terms of the following: Patient Related Tennis Elbow Evaluation (PRTEE), Visual Analogue Scale (VAS), and Disabilities of the Arm, Shoulder, and Hand (DASH), which were detected at preintervention, 6-, 12-, 24-, and 36-month follow-up. Secondary outcomes included complications and the need for any surgery at follow-up. Results: Primary outcome measurements showed significantly better results favoring the PRP group (6-month PRTEE total 43.2 ± 19.2 vs. 62.8 ± 24.0, p < 0.001; 12-month PRTEE total 6.9 ± 15.0 vs. 28.1 ± 24.4, p < 0.001; 24-month PRTEE total 4.8 ± 9.8 vs. 12.7 ± 14.5, p = 0.029), and significantly better results in VAS and DASH sub-scores. The PRP group required significantly fewer surgical procedures (n = 0/0% vs. n = 6/20%, p = 0.027) at follow-up (mean 38.3 ± 12.3 months), and one case of prolonged pain after injection was detected. Conclusions: Patients who underwent PRP injections for epicondylitis resulted in better pain and functional outcomes compared to physiotherapy, and this improvement lasted at least 24 months. They required fewer surgical procedures and achieved faster recovery than the PT group. We recommend PRP for chronic epicondylitis of the elbow before considering surgery when other treatments have failed.

Platelet-Rich Plasma Gel Matrix (PRP-GM): Description of a New Technique

Several musculoskeletal conditions are triggered by inflammatory processes that occur along with imbalances between anabolic and catabolic events. Platelet-rich plasma (PRP) is an autologous product derived from peripheral blood with inherent immunomodulatory and anabolic properties. The clinical efficacy of PRP has been evaluated in several musculoskeletal conditions, including osteoarthritis, tendinopathy, and osteonecrosis. When used in combination with hyaluronic acid (HA), a common treatment alternative, the regenerative properties of PRP are significantly enhanced and may provide additional benefits in terms of clinical outcomes. Recently, a new PRP-derived product has been reported in the literature and is being referred to as "plasma gel". Plasma gels are obtained by polymerizing plasmatic proteins, which form solid thermal aggregates cross-linked with fibrin networks. Plasma gels are considered to be a rich source of growth factors and provide chemotactic, migratory, and proliferative properties. Additionally, clot formation and the associated fibrinolytic reactions play an additional role in tissue repair. There are only a few scientific articles focusing on plasma gels. Historically, they have been utilized in the fields of aesthetics and dentistry. Given that the combination of three products (PRP, HA, and plasma gel) could enhance tissue repair and wound healing, in this technical note, we propose a novel regenerative approach, named "PRP-HA cellular gel matrix" (PRP-GM), in which leukocyte-rich PRP (LR-PRP) is mixed with a plasma gel (obtained by heating the plasma up) and HA in one syringe using a three-way stopcock. The final product contains a fibrin-albumin network entangled with HA's polymers, in which the cells and biomolecules derived from PRP are attached and released gradually as fibrinolytic reactions and hyaluronic acid degradation occur. The presence of leukocytes, especially monocytes and macrophages, promotes tissue regeneration, as type 2 macrophages (M2) possess an anti-inflammatory feature. In addition, HA promotes the viscosuplementation of the joint and induces an anti-inflammatory response, resulting in pain relief. This unique combination of biological molecules may contribute to the optimization of regenerative protocols suitable for the treatment of degenerative musculoskeletal diseases.

Leukocyte and Platelet-Rich Plasma (L-PRP) in Tendon Models: A Systematic Review and Meta-Analysis of in vivo/in vitro Studies

Purpose

To perform a systematic review on the application of leukocyte- and platelet-rich plasma (L-PRP) in tendon models by reviewing in vivo/in vitro studies.

Methods

The searches were performed via electronic databases including PubMed, Embase, and Cochrane Library up to September 2022 using the following keywords: ((tenocytes OR tendon OR tendinitis OR tendinosis OR tendinopathy OR tendon injury) AND (platelet-rich plasma OR PRP OR autologous conditioned plasma OR leukocyte- and platelet-rich plasma OR L-PRP OR leukocyte-richplatelet-rich plasma Lr-PRP)). Only in vitro and in vivo studies that assessed the potential effects of L-PRP on tendons and/or tenocytes are included in this study. Description of PRP, study design and methods, outcomes measured, and results are extracted from the data.

Results

A total of 17 studies (8 in vitro studies and 9 in vivo studies) are included. Thirteen studies (76%) reported leukocyte concentrations of L-PRP. Four studies (24%) reported the commercial kits. In in vitro studies, L-PRP demonstrated increased cell proliferation, cell migration, collagen synthesis, accelerated inflammation, and catabolic response in the short term. In addition, most in vivo studies indicated increased collagen type I content. According to in vivo studies reporting data, L-PRP reduced inflammation response in 71.0% of studies, while it enhanced the histological quality of tendons in 67.0% of studies. All 3 studies reporting data found increased biomechanical properties with L-PRP treatment.

Conclusions

Most evidence indicates that L-PRP has some potential effects on tendon healing compared to control. However, it appears that L-PRP works depending on the biological status of the damaged tendon. At an early stage, L-PRP may accelerate tendon healing, but at a later stage, it could be detrimental.

Modifying Orthobiological PRP Therapies Are Imperative for the Advancement of Treatment Outcomes in Musculoskeletal Pathologies

Autologous biological cellular preparations have materialized as a growing area of medical advancement in interventional (orthopedic) practices and surgical interventions to provide an optimal tissue healing environment, particularly in tissues where standard healing is disrupted and repair and ultimately restoration of function is at risk. These cellular therapies are often referred to as orthobiologics and are derived from patient's own tissues to prepare point of care platelet-rich plasma (PRP), bone marrow concentrate (BMC), and adipose tissue concentrate (ATC). Orthobiological preparations are biological materials comprised of a wide variety of cell populations, cytokines, growth factors, molecules, and signaling cells. They can modulate and influence many other resident cells after they have been administered in specific diseased microenvironments. Jointly, the various orthobiological cell preparations are proficient to counteract persistent inflammation, respond to catabolic reactions, and reinstate tissue homeostasis. Ultimately, precisely delivered orthobiologics with a proper dose and bioformulation will contribute to tissue repair. Progress has been made in understanding orthobiological technologies where the safety and relatively easy manipulation of orthobiological treatment tools has been demonstrated in clinical applications. Although more positive than negative patient outcome results have been registered in the literature, definitive and accepted standards to prepare specific cellular orthobiologics are still lacking. To promote significant and consistent clinical outcomes, we will present a review of methods for implementing dosing strategies, using bioformulations tailored to the pathoanatomic process of the tissue, and adopting variable preparation and injection volume policies. By optimizing the dose and specificity of orthobiologics, local cellular synergistic behavior will increase, potentially leading to better pain killing effects, effective immunomodulation, control of inflammation, and (neo) angiogenesis, ultimately contributing to functionally restored body movement patterns.

Platelet lysate and tendon healing: comparative analysis of autologous frozen-thawed PRP and ketorolac tromethamine in the treatment of patients with rotator cuff tendinopathy

Platelet-rich blood derivatives are being nowadays increasingly used in the treatment of tendon-related pathologies as a rich source of growth factors. We sought to ascertain if local application of platelet lysate (PL) to augment rotator cuff repair ameliorates patient outcomes compared to ketorolac tromethamine treated group. A total of forty patients, with clinical diagnosis of Rotator Cuff Tendinopathy were randomized to receive sub acromial injections of PL every week for a total of 3 injections and two injection of ketorolac tromethamine once every two weeks. Subjective assessments included VAS, SPADI and shoulder range of motion were assessed at baseline and at 1 and 6 months after injection. Taking both control and PL groups, it was vividly seen that the outcomes were identical at the initial state, as well as the short-term one; whereas, when considering the 6-month period, there is a seemingly remarkable superiority in PL group in all parameters.

Advances toward transformative therapies for tendon diseases

Approved therapies for tendon diseases have not yet changed the clinical practice of symptomatic pain treatment and physiotherapy. This review article summarizes advances in the development of novel drugs, biologic products, and biomaterial therapies for tendon diseases with perspectives for translation of integrated therapies. Shifting from targeting symptom relief toward disease modification and prevention of disease progression may open new avenues for therapies. Deep evidence-based clinical, cellular, and molecular characterization of the underlying pathology of tendon diseases, as well as therapeutic delivery optimization and establishment of multidiscipline interorganizational collaboration platforms, may accelerate the discovery and translation of transformative therapies for tendon diseases.

Swiss Medical Devices for Autologous Regenerative Medicine: From Innovation to Clinical Validation

Regenerative medicine, based on the use of autologous tissues and embryonic, stem or differentiated cells, is gaining growing interest. However, their preparation, in a manner compliant with good practices and health regulations, is a technical challenge. The aim of this manuscript is to present the design of reliable CE marked medical devices for the preparation of standardized platelet-rich plasma (PRP) and other autologous biologics intended for therapeutic uses. There are numerous PRP isolation processes. Depending on the methodology used, PRP composition varies greatly in terms of platelet concentration, platelet quality, and level of contamination with red and white blood cells. This variability in PRP composition might affect the clinical outcomes. The devices presented here are based on a specific technology, patented all over the world, that allows the precise separation of blood components as a function of their density using thixotropic separator gels in closed systems. This allows the preparation, in an automated manner, of leukocyte poor PRP with a standardized composition. Production of different forms of PRP is a clinical asset to suit various therapeutic needs. Therefore, we are offering solutions to prepare PRP either in liquid or gel form, and PRP combined with hyaluronic acid. These biologics have been successfully used in many different therapeutic domains, resulting in more than 150 published clinical studies. We also developed the CuteCell technology platform for cell culture expansion for further autologous cell therapies. This technology enables the safe and rapid in vitro expansion of cells intended for therapeutic use in good manufacturing practices (GMP) and autologous conditions, using blood-derived products as culture media supplementation. We summarize in this article our 20 years’ experience of research and development for the design of PRP devices and, more recently, for PRP combined with hyaluronic acid.

Risks in Induction of Platelet Aggregation and Enhanced Blood Clot Formation in Platelet Lysate Therapy: A Pilot Study

Platelet concentrates (PCs) are widely used in regenerative medicine; as it is produced from freeze-thawing PC, platelet lysate (PL) has a longer shelf life. The thrombotic risk of PL therapy needs to be explored since PL and PC contain cytokines that contribute to platelet aggregation and thrombus formation. Whole blood samples of 20 healthy subjects were collected; PL was produced from PCs with expired shelf life through freeze-thawing. The direct mixing of PL with platelet-rich plasma (PRP) or whole blood was performed. In addition, rotational thromboelastometry (ROTEM) was used to investigate whether PL enhanced coagulation in vitro; the effects of fibrinogen depletion and anticoagulants were evaluated to prevent hypercoagulation. The results showed that PL induced platelet aggregation in both PRP and whole blood. In ROTEM assays, PL was shown to cause a significantly lower clotting onset time (COT) and clot formation time (CFT), and a significantly greater α angle and maximum clot firmness (MCF). Compared with the controls, which were 1:1 mixtures of normal saline and whole blood, fibrinogen depletion of PL showed no significant difference in CFT, α angle and MCF. Moreover, heparin- and rivaroxaban-added PL groups demonstrated no clot formation in ROTEM assays. Platelet lysate-induced hypercoagulability was demonstrated in vitro in the present study, which could be prevented by fibrinogen depletion or the addition of an anticoagulant.

Efficacy of Platelet-Rich Plasma Injection in the Management of Rotator Cuff Tendinopathy: A Review of the Current Literature

Platelet-rich plasma (PRP) is being projected as a newer and superior treatment option for rotator cuff tendinopathy. With the first use of PRP in trauma and orthopedics dating back only to 1998, its advent into the field is relatively recent. Thus, data on long-term efficacy, large cohort studies, or large randomized controlled trials are fairly limited. Moreover, owing to the absence of standardized methods of platelet extraction and lack of consensus on the ideal concentration of platelets in PRP, data comparison from different studies is difficult. Things are complicated by the fact that it is also not clear whether a single injection of PRP is therapeutic or if multiple serial injections are needed to produce the desired effects. The literature on efficacy and pain relief is also obtained from studies with low sample sizes and short follow-ups. The dropout rate and noncompliance rate were also found to be high in some studies. Thus, the data is often not clinically significant and may also be biased due to the non-standardized inclusion and exclusion criteria of the studies. Though multiple studies have suggested good pain control with PRP injection, many studies have found that PRP injection therapy may not be any better than the physical therapy regimen prescribed to patients with rotator cuff tendinopathy. Also, the data on the efficacy of PRP on shoulder function and shoulder range of motion is at variance. This submission aims to evaluate the efficacy and use of PRP in the management of rotator cuff tendinopathy.

What Role Does PDGFA Gene Polymorphisms Play in Treating Tennis Elbow with PRP? A Prospective Cohort Study

BACKGROUND

This study aims to identify genotype variants of the platelet-derived growth factor alpha polypeptide gene (PDGFA) that can influence the individual response to the treatment with platelet-rich plasma (PRP) in tennis elbow patients.

METHODS

We observed a cohort of 107 patients (132 elbows) with tennis elbow who received treatment with PRP. Patients have been followed-up for two years after PRP injection and the effectiveness of the treatment was measured using universal patient-reported outcome measures (PROMs): visual analog scale (VAS), quick version of disabilities of the arm, shoulder and hand score (QDASH), and patient-rated tennis elbow evaluation (PRTEE). PROMs values, and clinical and platelet parameters were compared between genotype variants of the studied polymorphisms (rs1800814, rs2070958 and rs62433334).

RESULTS

The A allele carriers (rs1800814) had significantly lower values of VAS (week 12), QDASH, and PRTEE (weeks 8, 12). The T allele carriers (rs2070958) had significantly lower values of VAS (weeks 8, 12), QDASH, and PRTEE (weeks 4-12). Additional forms of therapy (manual and physical) were necessary significantly more often in GG (rs1800814) and CC (rs2070958) homozygotes.

CONCLUSIONS

The PDGFA gene's polymorphisms influences the effectiveness of PRP therapy in tennis elbow treatment. The effectiveness of PRP is greater in A allele (rs1800814) and T allele (rs2070958) carriers.

Patient registries in orthopedics and orthobiologic procedures: a narrative review

There has been increasing evidence and growing popularity of orthobiologic treatments, such as platelet-rich plasma, bone marrow aspirate concentrate, and microfragmented adipose tissue. However, real-world data, including patient-reported pain and function outcomes, remains sparse for these procedures. Thus, collecting patient-reported outcome measures is important to evaluate the safety and efficacy of these treatments and hopefully improve patient care. Patient reported outcome measures can systematically be collected through patient registries. This narrative review serves to describe the data collection platforms and registries that obtain patient-reported outcome measures on orthobiologic procedures and provide a discussion on the benefits and limitations of registries. An internet search of the list of orthopedic registries available was conducted, and registries that collect patient-reported outcome measures for orthobiologic procedures were identified. Additional information regarding these various registries was collected by directly contacting these vendors. Publications from these registries, including case series, observational studies, and annual reports, were also reviewed. Providing this review will inform clinicians of a digital tool that can increase the efficiency of collecting outcome measures for orthobiologics and aid physicians in choosing a data collection platform.

Dextrose Effects on Platelet Count and Volume: Implications for Regenerative Medicine

Platelet-rich plasma (PRP) and hypertonic dextrose solutions are commonly used injectates in regenerative medicine, sometimes used simultaneously. The effects of hypertonic dextrose on platelet lysis and activation have not been previously reported. We tested the effects of escalating dextrose concentration on cell counts and cell volume of platelets and red cells in PRP and whole blood (WB). A prompt partial reduction in platelet count occurred with all dextrose admixtures with either PRP or whole blood, consistent with partial lysis. After the first minute, platelet counts remained stable, suggesting a rapid accommodation of residual platelets to extreme (>2000 mOsm) hypertonicity. A 25% or higher dextrose concentration caused a significant increase in mean platelet volume (MPV), which suggests an early phase of platelet activation. Further investigation is warranted to confirm if platelet lysis or activation has occurred and whether additive clinical benefit may result from hypertonic dextrose injection alone or in combination with PRP.

Bibliometric analysis of the top 50 highly cited articles on platelet-rich plasma in osteoarthritis and tendinopathy

The primary goal of this study was to compile the top 50 most cited articles on the use of platelet-rich plasma (PRP). A search of relevant studies was performed in accordance with the PRISMA guidelines in Web of Science. The top 25 most cited articles in osteoarthritis and tendinopathy were then compiled and evaluated. Level 1 evidence articles constituted the majority of the studies (64%) and were more likely to have a higher citation density. Altmetric data was highest for level 1 systematic reviews. Of the articles that report a positive outcome for PRP, 13% (2/16) had low risk of bias. This study defines the most cited and influential publications regarding PRP to further research in this area.

Platelet-Rich Plasma as an Orthobiologic: Clinically Relevant Considerations

Platelet-rich plasma (PRP) is an autologous blood-derived product processed to concentrate platelets and the associated growth factors. PRP has been shown to be relatively well-tolerated and safe to use for a number of conditions in humans, equines, and canines. There are multiple commercial systems that have been validated for canine use. These systems use a variety of methodologies to produce a PRP product. However, PRP products have been shown to differ greatly between systems. Further study is needed to fully elucidate optimal component concentrations for various indications.

Platelet-rich plasma therapy ensures pain reduction in the management of lateral epicondylitis - a PRISMA-compliant network meta-analysis of randomized controlled trials

OBJECTIVES

Analyze the effectiveness of PRP therapy in comparison to other available treatments in the management of lateral epicondylitis (LE).

MATERIALS AND METHODS

We conducted electronic database searches in PubMed, Embase, Web of Science, and Cochrane Library until June 2021 for RCTs analyzing the efficacy of PRP in the management of LE. VAS for pain, DASH score, and PRETEE score were the outcomes analyzed. The analysis was performed in R-platform using MetaInsight and interventions were ranked based on p-score approach. Cochrane's CINeMA approach was used for quality appraisal.

RESULTS

Twenty-five RCTs with 2040 patients were included in the network analysis. Compared to saline control, only leukocyte-rich-PRP resulted in significant pain relief (WMD=-14.8,95% CI [-23.18,-6.39];low confidence) compared to steroid, local anesthetic, laser, and surgery. On analyzing DASH scores and PRETEE scores, none of the above-mentioned treatment methods were superior to saline control. In subgroup analysis, leucocyte-rich-PRP resulted in clinically significant improvement. Leucocyte-rich-PRP seems more promising with p-score of 0.415.

CONCLUSION

PRP therapy offers significant pain relief compared to saline control in the management of LE without similar improvement in functional outcome. With available low-quality evidence, PRP was the most promising therapy that needs further exploration to explore its usefulness in lateral epicondylitis.

The effect of leucocyte concentration of platelet-rich plasma on outcomes in patients with lateral epicondylitis: a systematic review and meta-analysis

HYPOTHESIS

The concentration of leukocytes influences the quality of platelet-rich plasma (PRP). However, there is no consensus on which type of PRP based on the concentration of leukocytes is the best for lateral epicondylitis (LE).

METHODS

We systematically searched the MEDLINE, Embase, and Cochrane Library databases until March 1, 2020. Studies involving randomized controlled trials, patients with LE, and treatment with PRP injections were included. PRP was classified into leukocyte-poor (LP) PRP and leukocyte-rich (LR) PRP. LR-PRP was defined as PRP with a white blood cell concentration exceeding that of whole blood (4.0-10.0 per μL³), whereas LP-PRP was defined as PRP with a lower white blood cell concentration than that of whole blood. The efficacy of PRP was assessed using the visual analog scale (VAS) and success rates.

RESULTS

Eleven randomized controlled trials (six involving LP-PRP and five involving LR-PRP) were eligible for inclusion in this review. Eight studies were included in the meta-analysis to evaluate the VAS score. Regarding short-term follow-up, there was no difference in the VAS scores between the LP-PRP and control groups (standard mean difference [SMD], 0.01; 95% confidence interval [CI], -0.29 to 0.30; P = 0.97), with no heterogeneity (I² = 0%). There was also no difference in the VAS scores between the LR-PRP and control groups (SMD, -0.19; 95% CI, -0.57 to 0.20; P = 0.34), with substantial heterogeneity (I² = 56.7%). Regarding long-term follow-up, there was no difference in the VAS scores between the LP-PRP and control groups (SMD, -0.73; 95% CI, -1.69 to 0.23; P = 0.134) with substantial heterogeneity (I² = 88.4%). The LR-PRP group had lower VAS scores than the control group (SMD, -1.06; 95% CI, -2.02 to -0.09; P = 0.032) with substantial heterogeneity (I² = 92%). In the LP-PRP group, there was no significant difference in the success rate (odds ratio, 1.08; 95% CI, 0.07-16.47; P = 0.956) with substantial heterogeneity (I² = 87.7%). In the LR-PRP group, however, the patients who received PRP had a higher success rate than those in the control group (odds ratio, 2.85; 95% CI, 1.67-4.85; P < 0.01) with substantial heterogeneity (I² = 82.9%).

CONCLUSION

LR-PRP may provide pain relief and successful outcomes for patients with LE compared with alternative local injections. Better results were observed with the use of LR-PRP than with the use of LP-PRP.

Platelet-rich plasma injection vs. operative treatment for lateral elbow tendinosis: a systematic review and meta-analysis

BACKGROUND

Although surgical treatment is considered reliable for lateral elbow tendinosis, local injection therapy may be preferable, as it avoids surgery. Among a number of local injections, platelet-rich plasma has been used successfully to treat lateral elbow tendinosis. The purpose of this study was to compare the outcomes in patients treated with either platelet-rich plasma injections or surgery for lateral elbow tendinosis using a systematic literature review and meta-analysis.

METHODS

MEDLINE, Embase, and Cochrane Library databases were systematically searched for studies published before March 1, 2021, that compared platelet-rich plasma with operative treatment for lateral elbow tendinosis. The pooled analysis was designed to compare the visual analog scale scores and the Patient-Related Tennis Elbow Evaluation scores between the platelet-rich plasma and surgical treatment groups at serial time points.

RESULTS

We included 5 studies involving 340 patients with lateral elbow tendinosis, comprising of 154 patients treated with platelet-rich plasma and 186 patients who underwent surgical treatment. The pooled analysis showed no statistically significant differences in the visual analog scale scores at any of the follow-up time points, namely, 2 months (mean difference [MD] 1.11, 95% confidence interval [CI] -2.51 to 4.74, P = .55, I² = 94%), 6 months (MD 0.80, 95% CI -2.83 to 4.42, P = .67, I² = 92%), and 12 months (MD -0.92, 95% CI -4.63 to 2.80, P = .63, I² = 93%) postintervention and in the Patient-Related Tennis Elbow Evaluation scores at 12 weeks (MD -1.86, 95% CI -22.30 to 18.58, P = .86, I² = 81%), 24 weeks (MD -3.33, 95% CI -21.82 to 15.17, P = .72, I² = 74%), and 52 weeks (MD -3.64, 95% CI -19.65 to 12.37, P = .66, I² = 69%) postintervention.

CONCLUSIONS

Local platelet-rich plasma injections and surgical treatment produced equivalent pain scores and functional outcomes in patients with lateral elbow tendinosis. Thus, platelet-rich plasma injections may represent a reasonable alternative treatment for patients who are apprehensive to proceed with surgery or for poor surgical candidates.

Applications of the regenerative capacity of platelets in modern medicine

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