Platelet-rich plasma: why intra-articular? A systematic review of preclinical studies and clinical evidence on PRP for joint degeneration

Does intra-articular injection of PRP help patients with temporomandibular joint osteoarthritis after joint puncture? a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The aim of this study is to conduct a systematic review to evaluate whether intra-articular injection of platelet-rich plasma (PRP) after joint puncture can aid in the recovery of patients with temporomandibular joint osteoarthritis (TMJOA).

METHODS

We searched PubMed, Cochrane Library, Embase and Web of Science as of March 3, 2024. Retrieved a total of 392 articles. We included all published randomized controlled trials (RCTs). All RCTs, including studies on PRP injection after joint puncture in patients with TMJOA. The primary outcome was pain reduction, and the secondary outcome was the improvement of maximal mouth opening (MMO) and joint sounds. All outcome measures were analyzed by calculating the standardized mean differences (SMDs) and 95% confidence intervals (CIs).

RESULTS

A total of 392 articles were retrieved, and ultimately, 6 articles met the inclusion criteria. The study involved 199 TMJOA patients. The results indicated that compared to the control group, PRP injection after joint puncture showed significant improvements in alleviating pain (SMD =-0.99; 95% CI =-1.35 ~-0.63; P <0.00001, I2 = 59%) and MMO (SMD = 0.63; 95% CI = 0.30 ~ 0.95; P <0.0002, I2 = 54%) among TMJOA patients. However, there was no significant improvement observed in terms of joint sounds (SMD =-0.34; 95% CI = -0.71 ~ 0.02; P = 0.06, I2 = 0%) with the PRP.

CONCLUSIONS

Compared to joint puncture alone, the intra-articular injection of PRP after joint puncture was more effective in relieving pain. At 1-month and 6-month follow-ups, patients in the PRP group showed significant improvements in MMO compared to the control group. However, after 12 months of follow-up, limited evidence indicated significant improvements in MMO and joint sounds.

Side-to-side characterisation of cellular content, soluble factors and in vitro potential on chondrocytes for bone marrow aspirate concentrate and adipose-derived stromal vascular fraction

Purpose

Orthobiologics gained popularity for the treatment of musculoskeletal pathologies, including osteoarthritis (OA). Bone marrow aspirate concentrate (BMAC) and adipose-derived stromal vascular fraction (SVF) were reported to reduce OA symptoms, contributing to the restoration of joint homoeostasis. Variability in production protocols and lack of extensive characterisation hinder a clear indication for the choice of a product over the other. The purpose of this study was to characterise side-by-side BMAC and SVF obtained with the same family of devices, by assessing cell immunophenotype, release of soluble factors and their ability to reduce inflammation in a pathologic in vitro chondrocyte model.

Methods

BMAC (iliac crest) and SVF (abdomen liposuction) were obtained from 28 (55 years old ± 8) and 39 patients (56 years old ± 9), with Hy-Tissue BMAC and Hy-Tissue SVF. BMAC/SVF were characterised for cellular content. The number of mesenchymal stromal cells (MSCs) was investigated by flow cytometry (CD45-CD31-CD34+CD90+CD105-/LCD146-, adipose-MSCs; CD45-CD271+, bone marrow-MSCs). Two-hundred factors (cytokines, chemokines, receptors, growth factors and inflammatory molecules) were tested by enzyme-linked immunosorbent assay (ELISA). Anti-inflammatory potential was assayed in vitro on interleukin-1 beta (IL1β)-treated chondrocytes by quantitative reverse transcription polymerase chain reaction (qRT-PCR) arrays of 84 genes involved in inflammatory processes.

Results

BMAC had higher concentration for white cells (213x), erythrocytes (49x) and platelets (25x), while the number of MSCs resulted comparable between the two products (1000 cells/mL). One-hundred and twenty-one soluble factors were identified in all analysed samples, with 88 more abundant in BMAC and one in SVF. Gene ontology revealed that the higher concentrated molecules were mainly growth factors and/or involved in differentiation processes. Both orthobiologics reduced inflammation in the in vitro chondrocyte model, with BMAC showing higher efficacy.

Conclusions

Using specific commercial systems, both orthobiologics showed anti-inflammatory effects in vitro. BMAC had higher blood cell and growth factor concentrations than SVF, with greater efficacy. However, variability in commercial systems limits generalisation, requiring further study to draw conclusions when different devices are employed.

Level of Evidence

NA.

Effectiveness and Safety of Platelet-Rich Plasma Combined with Pulsed Radiofrequency to Treat Patients with Infraorbital Neuralgia: A Propensity Score-Matched Analysis of a Multi-Center, Prospective Cohort Protocol

Background

Infraorbital neuralgia (IONa) is a rare but devastating type of facial pain, with a lack of current consensus on its proper management. Preliminary studies have established the efficacy of pulsed radiofrequency (PRF) in the treatment of IONa. Platelet-rich plasma (PRP) is a non-destructive technique that alleviates neuropathic pain. Till date, the efficacy of PRP combined with PRF in the treatment of IONa has not been evaluated yet.

Objective

To evaluate the efficacy and safety of PRP combined with PRF in treating refractory IONa in patients unwilling to undergo destructive therapies.

Study Design

A multicenter, prospective, observational, propensity score matching (PSM), and assessor-blinded study.

Setting

Department of pain management in Beijing, Wuhan and Qingdao, China.

Methods

A total of 240 refractory IONa patients will be allocated to either PRP combined with PRF therapy (PRP+PRF) group or PRF therapy alone (PRF) group at their own volition. Statistical analysis will be performed using Pearson's chi-squared or Fisher's exact test for categorical variables, Student's t-test and Mann-Whitney U-test for continuous variables. Logistic regression will be used to evaluate the pain - relief efficacy.

Results

The primary outcome will be the 12-months response rate. The secondary outcome will include NRS score, total daily dose of carbamazepine, the 12-item Short-Form Health Survey (SF-12) scores, patient satisfaction scores (PSS) and adverse events (AEs).

Limitation

This is an observational, open-labeled study with a relatively short term follow-up. The composition of PRP and various cell ratios, which are optimal for IONa has not been published yet.

Conclusion

This will be a multi-center trial with a relatively large sample size, demonstrating the potential benefits of PRP combined with PRF therapy in IONa patients. Further, randomized controlled trial (RCT) will be necessary to confirm the efficacy of this combined therapy.

PRP Injections for the Treatment of Knee Osteoarthritis: The Improvement Is Clinically Significant and Influenced by Platelet Concentration: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Platelet-rich plasma (PRP) has emerged as a promising therapeutic intervention for knee osteoarthritis (OA), attracting substantial clinical and research attention. However, the clinical relevance of the treatment benefit remains controversial.

PURPOSE

To evaluate the effectiveness of PRP compared with placebo in patients with knee OA in terms of minimal clinically important difference (MCID) and to investigate the possible influence of platelet concentration on the clinical outcome.

STUDY DESIGN

Meta-analysis. Level of evidence 1.

METHODS

The search was conducted on 5 databases (PubMed, Cochrane Library, Scopus, Embase, Web of Science) using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Inclusion criteria were randomized controlled trials comparing PRP and placebo injections to treat knee OA, written in the English language, with no time limitation. The effects were quantified at 1-, 3-, 6-, and 12-month follow-up points. Visual analog scale (VAS) for pain and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were used, with subanalyses based on platelet concentration performed using a 1,000,000 ± 20% platelets/µL cutoff. The MCID values (VAS, 1.37; WOMAC, 6.4) were used to interpret clinical improvement. The articles' quality was assessed using the Revised Tool for Risk of Bias in Randomized Trials and the Grading of Recommendations Assessment, Development and Evaluation guidelines.

RESULTS

Among the 5499 articles retrieved, 18 randomized controlled trials (1995 patients) were included. PRP presented statistically superior improvements in VAS and WOMAC scores compared with placebo at all follow-up points, exceeding the MCID at 3- and 6-month follow-up points for VAS and at all follow-up points for WOMAC. The subanalysis based on platelet concentration showed that high-platelet PRP provided clinically significant pain relief with the improvement exceeding the MCID compared with placebo at 3-, 6-, and 12-month follow-up points. In contrast, low-platelet PRP failed to offer a clinically perceivable benefit in terms of VAS score. WOMAC results showed that both products provided a clinically significant improvement at 3 and 6 months of follow-up. This benefit was maintained up to the 12-month follow-up in the high-platelet group but not in the low-platelet group, where the improvement compared with placebo did not reach statistical significance.

CONCLUSION

This meta-analysis showed that PRP offered clinically relevant functional improvement at 1-, 3-, 6-, and 12-month follow-up points and pain relief at 3- and 6-month follow-up points compared with placebo for the treatment of knee OA. Platelet concentration was found to influence treatment efficacy, with high-platelet PRP providing superior pain relief and more durable functional improvement compared with low-platelet PRP.

The Combined Use of Triamcinolone and Platelet-Rich Plasma in Equine Metacarpophalangeal Joint Osteoarthritis Treatments: An In Vivo and In Vitro Study

Intra-articular corticosteroids, such as triamcinolone acetonide (TA), help reduce pain related to osteoarthritis (OA), but they may impair cartilage metabolism. In contrast, platelet-rich plasma (PRP) therapy, a regenerative therapy, has shown potential to promote healing and regeneration of articular cartilage. This study investigates the effects of combining PRP with TA to treat osteoarthritis in racehorses. The study proposes that PRP injection following TA treatment could reduce side effects and improve treatment outcomes. Firstly, in the in vitro study, chondrocytes were exposed to different TA concentrations, with or without PRP. TA dramatically reduced chondrocyte viability. However, this was prevented by the addition of PRP, which also increased cell proliferation. In the in vivo study, 32 racehorses with metacarpophalangeal (MCP) joint OA were separated into two groups: one received only TA, while the other received TA followed by PRP. For both groups, there were improved flexion assessments one week following the last treatment, but by two weeks following the last treatment, only TA+PRP had improved flexion assessments. TA+PRP also had improved lameness scores two weeks after the last treatment. In conclusion, combining PRP with TA could enhance chondrocyte viability and provide a better long-term therapeutic option for treating OA in racehorses. Further trials are required to thoroughly assess this technique's safety and efficacy.

Protocol for a multicentre randomised triple-blind controlled trial assessing the clinical efficacy of intra-articular platelet-rich plasma injections versus placebo in symptomatic knee osteoarthritis (PIKOA)

INTRODUCTION

Despite their exponential use, intra-articular (IA) injections of platelet-rich plasma (PRP) are not part of the recommended treatments for knee osteoarthritis (OA) by most international scientific societies. The most recent clinical trials have shown conflicting results, and some did not find any clinical benefit of PRP injections. The PRP In Knee OsteoArthritis (PIKOA) trial was designed to assess the clinical efficacy and structural benefit of IA injections of PRP vs saline solution (placebo) in symptomatic knee OA.

METHODS AND ANALYSIS

PIKOA is an academic phase 3, superiority, triple-blind (patients, investigators and injectors), multicentre, randomised placebo-controlled trial (1:1 ratio). It compares the efficacy of 1 weekly IA injection of 5 mL PRP or placebo (saline solution) for 3 weeks with a 6-month follow-up. The trial will enrol 210 participants ≥40 years old with symptomatic and moderate radiographic knee OA (Kellgren and Lawrence grade 2 or 3). PRP is prepared with the A-CP-Kit-T (20 mL) kit and its cellular composition is characterised for each patient. The main objective is to compare change in pain on a 0 mm to 100 mm visual analogue scale (VAS) between W0 and W14. The secondary objectives are to compare the two groups in terms of decrease in VAS pain, Western Ontario and McMaster Universities Osteoarthritis Index total score and subscores, analgesics consumption, OMERACT-Osteoarthritis Research Society International responder rate and improvement in quality of life measured by the EQ-5D-5L score. All these criteria are assessed at W8, W14 and W26. The decrease in serum Coll2-1 and Coll2-1 NO₂ levels (catabolic markers, reflecting cartilage destruction or joint inflammation) and increase in N-propeptide of cartilage IIA level (reflecting cartilage formation) are assessed at W8 and W14. Adverse events and study withdrawals are collected during the study.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Nord Ouest ethical committee (2021-A00742-39). All participants need to provide written informed consent. The findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05378815 (ClinicalTrials.gov); pre-results.Protocol version and number: V.3 of 17 July 2023.

Platelet-rich plasma injections for the management of knee osteoarthritis: The ESSKA-ICRS consensus. Recommendations using the RAND/UCLA appropriateness method for different clinical scenarios

PURPOSE

The aim of this consensus was to develop evidence- and expert-based patient-focused recommendations on the appropriateness of intra-articular platelet-rich plasma (PRP) injections in different clinical scenarios of patients with knee osteoarthritis (OA).

METHODS

The RAND/UCLA Appropriateness Method was used by the European Society of Sports Traumatology, Knee Surgery, and Arthroscopy (ESSKA), as well as the International Cartilage Regeneration and Joint Preservation Society (ICRS) to reach a consensus and produce recommendations for specific patient categories combining best available scientific evidence with the collective judgement of a panel of experts.

RESULTS

Scenarios were defined based on first treatment vs first injective treatment vs second injective treatment, age (<50/50-65/66-80/>80), tibiofemoral vs patellofemoral involvement, OA level (Kellgren-Lawrence/KL 0-I/II-III/IV), and joint effusion (dry knee, minor-mild or major effusion). Out of 216 scenarios, in 84 (38.9%) the indication was considered appropriate, in 9 (4.2%) inappropriate and in 123 (56.9%) uncertain. The parameters associated with the highest consensus were PRP use after failed injective treatments (62.5%), followed by PRP after failed conservative treatments and KL 0-III scenarios (58.3%), while the highest uncertainty was found for PRP use as first treatment and KL IV OA (91.7% and 87.5% of uncertain scenarios, respectively).

CONCLUSION

This ESSKA-ICRS consensus established recommendations on the appropriateness or inappropriateness of PRP injections for the treatment of knee OA, providing a useful reference for clinical practice. PRP injections are considered appropriate in patients aged ≤80 years with knee KL 0-III OA grade after failed conservative non-injective or injective treatments, while they are not considered appropriate as first treatment nor in KL IV OA grade.

LEVEL OF EVIDENCE

Level I.

Platelet-Rich Plasma Injections Do Not Improve the Recovery After Arthroscopic Partial Meniscectomy: A Double-Blind Randomized Controlled Trial

BACKGROUND

Arthroscopic meniscectomy is one of the most performed surgical procedures in orthopaedics. Different approaches have been proposed to improve patient recovery but with unsatisfactory results. Platelet-rich plasma (PRP) augmentation has been proposed as a strategy to improve the recovery after meniscectomy.

PURPOSE

To investigate the clinical benefits of an intra-articular PRP injection after meniscectomy, in terms of faster and better patient recovery.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Ninety patients were randomized into a treatment group, with arthroscopic partial meniscectomy immediately followed by a 5-mL injection of autologous conditioned plasma, and a control group with partial meniscectomy alone. Patients were evaluated at baseline and at 15, 30, 60, and 180 days of follow-up with the visual analog scale (VAS) score for pain (primary outcome), as well as with International Knee Documentation Committee subjective score, Knee injury and Osteoarthritis Outcome Score subscales, Tegner score, and EuroQol-Visual Analog Scale score. Objective evaluation was performed analyzing knee range of motion and circumference and the International Knee Documentation Committee objective score. Complications, patient judgment, and satisfaction were documented as well.

RESULTS

No major complications and an overall significant improvement in the clinical scores were observed in both groups. Overall, the comparative analysis did not demonstrate significant between-group differences in absolute values or improvements of both subjective and objective scores, as well as activity level. The improvement in terms of VAS pain score for the treatment group was significant already at 15 days (from 4.3 ± 2.5 to 2.5 ± 2.5; P = .014), while in the control group it became significant at 30 days (from 3.7 ± 2.3 to 2.0 ± 2.4; P = .004). No significant differences were observed between the 2 groups in terms of judgment of treatment results and satisfaction.

CONCLUSION

A single postoperative injection of PRP was not able to significantly improve patient recovery after arthroscopic partial meniscectomy. PRP augmentation did not provide overall benefits at a short-term follow-up (6 months) in terms of pain relief, function, objective parameters, and return-to-sport activities.

REGISTRATION

NCT02872753 (ClinicalTrials.gov identifier).

Corticosteroid injections for knee osteoarthritis offer clinical benefits similar to hyaluronic acid and lower than platelet-rich plasma: a systematic review and meta-analysis

Purpose

Intra-articular corticosteroid (CS) injections for knee osteoarthritis (OA) management are endorsed by several scientific societies, while the use of hyaluronic acid (HA) and platelet-rich plasma (PRP) is more controversial. Aim of the study was to quantify and compare the clinical effectiveness of CS injections with respect to HA and PRP in patients with knee OA.

Methods

The search was conducted on PubMed, Cochrane, and Web of Science following the PRISMA guidelines. Randomized controlled trials (RCTs) on the comparison of CS injections and HA or PRP injections for the treatment of knee OA were included. The minimal clinically important difference (MCID) was used to interpret the clinical relevance of the improvements at different follow-ups up to 12 months. The study quality was assessed using the Cochrane RoB-2 tool and the GRADE guidelines.

Results

Thirty-five RCTs were included (3348 patients). The meta-analysis comparing CS and HA revealed no difference in terms of WOMAC improvement, while HA showed superior VAS pain improvement at long-term follow-up (P = 0.011), without reaching the MCID. PRP offered a superior WOMAC improvement compared to CS at short- (P = 0.002), mid- (P < 0.001, exceeding the MCID), and long-term (P < 0.001, exceeding the MCID) follow-ups. PRP offered a superior VAS improvement at mid- (P < 0.001, exceeding the MCID) and long-term (P = 0.023) follow-ups.

Conclusion

CS injections for knee OA offer similar results to HA and PRP only at short term, while there is an overall superiority of PRP at longer follow-ups. This difference is not only statistically significant but also clinically relevant in favour of PRP.

Treatment of anterior knee pain due to chondromalacia patellae with platelet-rich plasma and hyaluronic acid in young and middle-aged adults, a cohort study

INTRODUCTION

Anterior knee pain commonly affects young women resulting in the declination of the quality of life. One of the possible pathologies causing this symptom is chondromalacia patellae (CMP). Although CMP is used to describe the softening of patellar articular cartilage, it remains a general descriptive term as it cannot be associated with a specific pathophysiologic mechanism. The objective of this study is to investigate the effect of injectable PRP on patients with anterior knee pain in absence of altered patellofemoral joint anatomy.

METHODS

For this purpose, 43 patients of the affected population were recruited to participate in this non-randomized controlled trial, 28 patients in the injection group and 15 in the only-physiotherapy group. While patients in the experimental group received three PRP injections and one injection of hyaluronic acid (HA), comparators received the standard physical therapy regimen. The treatment choice was based on patients own decree. Patients between the ages of 18 to 50 years with anterior knee pain and positive Clarke´s sign were eligible for inclusion. Patients with evident anatomical abnormalities, chronic conditions affecting the knee and severe symptoms such as blocking, were excluded from the study. Patient related measures (PROMS) in the form of the VAS and the Kujala scores were the main outcome of interest. All outcomes were measured at baseline, and after 3 and 6 months after the treatment.

RESULTS

Although an improvement was seen in both groups, a statistically significant difference favoring the injection of PRP over the physiotherapy-only group was observed (p < 0.001). The superiority of the therapeutic modality under investigation was observed at 3 and 6 months after the initial diagnosis was made. Furthermore, the results of this study revealed a significant improvement at 3 and 6 months when compared to baseline measures. The analysis of the patients age showed a negative correlation when baseline values were compared to measures at 3 and 6 months, meaning younger patients had more benefit from the treatment.

DISCUSSION

The main results of this study affirm the positive effects of PRP and HA for the treatment of anterior knee pain described by previous research and the subsequent improvement of the quality of life. Relatively little information was found in the literature search regarding the therapeutic effects of PRP on anterior knee pain and chondropathies. While a previous radiologic study found no evidence regarding the effect of PRP, this study found a benefit when comparing PROMs between patient groups.

Platelet-rich plasma augmentation in anterior cruciate ligament reconstruction: Evidence is still too scattered. A scoping review of randomised controlled trials

PURPOSE

Platelet-rich plasma (PRP) augmentation has been proposed to improve the results of anterior cruciate ligament reconstruction (ACLR). The present study aims to quantify the available evidence to support the use of PRP as biological augmentation in ACLR surgery.

METHODS

A systematic literature search was conducted on the PubMed, Cochrane, Web of Science and Embase databases on 10 March 2023. Inclusion criteria were randomised controlled trials (RCTs), written in English, addressing PRP augmentation in ACLR surgery, with no time limitation. A scoping review was performed to map the body of literature by examining the evidence related to specific aspects of patients' treatment and evaluation. Risk of bias evaluation was performed with the Cochrane risk-of-bias tool for randomised trials Version 2 (RoB 2), while the quality assessment was performed with the use of the Coleman Score.

RESULTS

Out of 983 articles retrieved, 23 RCTs on 943 knees were included in this scoping review. PRP was administered in a liquid form in nine studies and clotted in 11 studies, while in three studies both liquid and clotted PRP were used. Hamstring auto/allografts were used in 14 studies, patellar tendon auto/allografts were used in eight studies and one study described ACLR with peroneus longus allografts. The map of the evidence documented high heterogeneity also in terms of surgical technique, objective and subjective outcome measures and radiological assessment, as well as follow-up times ranging from 1 day to 2 years, with virtually no overlapping data among studies neither in terms of treatments nor evaluations. Risk of bias evaluation showed an overall low quality of the included studies.

CONCLUSIONS

The available literature addressing PRP augmentation in ACLR is largely scattered. PRP was produced and applied following different procedures, and high variability was detected across the included studies for every aspect of ACLR surgery and evaluation. Currently, a meaningful comparison of the available studies is not possible as the quantification of the literature results is biased by their heterogeneity. Future studies should provide more standardisation to investigate the benefits of biological augmentation in ACL surgery and confirm the promising yet weak evidence of PRP potential as well as the most suitable application modality, before routine use in clinical practice.

LEVEL OF EVIDENCE

Levels I and II, scoping review.

Platelet-rich plasma for jumper's knee: a comprehensive review of efficacy, protocols, and future directions

PURPOSE

This comprehensive review evaluates the current state of platelet-rich plasma (PRP) treatment for jumper's knee, also known as patellar tendinopathy. The aim is to assess the efficacy of PRP as a therapeutic option compared to other available procedures, investigate the benefits and potential drawbacks of PRP infiltration, and provide insights into the optimal protocols for PRP preparation and administration.

METHODS

A comprehensive literature search of English articles published up to June 2023 was conducted using PubMed and Scopus databases. Studies evaluating PRP for treating jumper's knee or patellar tendinopathy were analyzed to assess the current state of research in this field.

RESULTS

PRP has demonstrated promising results in promoting cellular remodeling and accelerating the healing process in the jumper's knee. It shows potential benefits in pain reduction, improved function, and accelerated recovery. However, the efficacy of PRP varies depending on patient characteristics, disease severity, and the specific administration methodology. Establishing standardized PRP preparation and administration protocols are necessary to optimize its effectiveness. Further research is needed to define appropriate patient selection criteria and refine the application of PRP therapy in patellar tendinopathy management.

CONCLUSION

Jumper's knee is commonly managed conservatively, but there is a lack of consensus on further treatment options. PRP treatment holds promise in promoting tissue healing and repair. However, standardized protocols for PRP preparation and administration, as well as optimal dosage and number of injections, require further investigation to enhance its efficacy. Continued research efforts are necessary to ascertain the precise role of PRP and its refinement in the management of patellar tendinopathy.

What Is the Efficacy of Intra-articular Injections in the Treatment of Ankle Osteoarthritis? A Systematic Review

BACKGROUND

Ankle osteoarthritis (OA) is painful and can impact a patient's physical and mental quality of life. Although intra-articular injections are commonly used to alleviate symptoms, there is conflicting evidence concerning their efficacy. Therefore, an updated systematic review would be informative.

QUESTION/PURPOSE

In this systematic review, we asked: Are there clinically important benefits or harms associated with the use of intra-articular injections in the treatment of ankle OA?

METHODS

We used PubMed, Embase, and the Cochrane Library to search for randomized controlled trials on intra-articular injections for the treatment of ankle OA in June 2021, and updated the search in January 2022; eligible dates were from the date of inception of each database through January 2022. Reference lists of eligible studies and previous reviews were manually screened. Two reviewers independently assessed studies for eligibility. We included seven studies. Three compared hyaluronic acid (HA) with saline, one compared HA with exercise, one compared four different regimens of HA [ 34 ], one compared platelet-rich plasma (PRP) with saline, and one compared botulinum toxin Type A (BoNT-A) with HA. A total of 340 patients were included: 141 in the HA arms, 48 in the PRP arm, 38 in the BoNT-A arm, and 113 in the saline arms. Across all studies, the mean age was 52 ± 21 years, and 35% were women (119 of 340 patients). Methodologic quality was assessed using the Cochrane Risk of Bias 2.0 tool. Of the included studies, the risk of bias was low in two studies, presented some concerns in one study, and was high in four studies. According to the Grading of Recommendations Assessment, Development, and Evaluation methodology, the level of evidence was very low for HA, moderate for PRP, and very low for BoNT-A. The level of heterogeneity was high, and we opted to perform a systematic review rather than a meta-analysis. A clinically relevant difference was based on whether the between-group difference surpassed the cutoff point determined as the minimum clinically important difference.

RESULTS

No clinically relevant differences were found among HA, PRP, and BoNT-A and their control groups at 3, 6, or 12 months. No studies reported any serious adverse events in any treatment group.

CONCLUSION

Given the lack of observed efficacy in this systematic review, these treatments should not be used in practice until or unless future high-quality studies find evidence of efficacy.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Platelet-Rich Plasma Intrauterine Infusion as Assisted Reproduction Technology (ART) to Combat Repeated Implantation Failure (RIF): A Systematic Review and Meta-Analysis

Background

Repeated implantation failure (RIF) is considered one of the major challenges facing clinician in assisted reproduction technologies (ART) despite the significant advances that have been made in this field. Platelet rich plasma (PRP), also known as autologous conditioned plasma, is a protein concentrate with anti-inflammatory and pro-regenerative characteristics. The use of PRP in women undergoing ART has been studied in the past, with varying degrees of success. The goal of this trial was to see if injecting PRP into the uterus improves pregnancy outcomes in women receiving ART.

Methods

PubMed, Embase, Scopus, Web of Science, and the Cochrane Database of Clinical Trials were among the databases searched (CENTRAL), from 2015 to 2021. The pooled estimates were calculated using a meta-analysis with a random-effects model. There were 14 studies with a total of 1081 individuals (549 cases and 532 controls).

Results

There was no difference in miscarriage rates between women who got PRP and those who received placebo (P≤0.90). Chemical pregnancy (P≤0.00), clinical pregnancy (P ≤0.001), and implantation rate (P≤ 0.001) were all significantly higher in women. Endometrial thickness increased in women who got PRP vs women who received placebo after the intervention (P ≤0.001).

Conclusion

PRP may be an alternate therapeutic approach for individuals with thin endometrium and RIF, according to the findings of this comprehensive study. To determine the subgroup that would benefit the most from PRP, more prospective, big, and high-quality randomized controlled trials (RCTs) are needed.

Platelet-Rich Plasma Injections for the Treatment of Ankle Osteoarthritis

BACKGROUND

Ankle osteoarthritis is debilitating and usually affects relatively young people, often as a result of previous ankle traumas, frequently occurring in sports. Platelet-rich plasma (PRP) injections for ankle osteoarthritis have shown no evidence of benefit over the course of 26 weeks. Previous studies on PRP for knee osteoarthritis showed that clinically significant improvements with PRP occurred between 6 to 12 months in the absence of initial benefit. No studies have evaluated the effect of PRP from 6 to 12 months in ankle osteoarthritis.

PURPOSE

To assess the efficacy of PRP injections in ankle osteoarthritis over the course of 52 weeks.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

In this 52-week follow-up trial, 100 patients with ankle osteoarthritis were randomized to a PRP group or placebo (saline) group. Patients received 2 intra-articular talocrural injections: at inclusion and after 6 weeks. Patient-reported outcome measures were used to assess pain, function, quality of life, and indirect costs over 52 weeks.

RESULTS

Two patients (2%) were lost to follow-up. The adjusted between-group difference for the patient-reported American Orthopaedic Foot & Ankle Society score over 52 weeks was -2 points (95% CI, -5 to 2; P = .31) in favor of the placebo group. No significant between-group differences were observed for any of the secondary outcome measures.

CONCLUSION

For patients with ankle osteoarthritis, PRP injections did not improve ankle symptoms and function over 52 weeks compared with placebo injections.

REGISTRATION

NTR7261 (Netherlands Trial Register).

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Latest insights in disease-modifying osteoarthritis drugs development

Osteoarthritis (OA) is a prevalent and severely debilitating disease with an unmet medical need. In order to alleviate OA symptoms or prevent structural progression of OA, new drugs, particularly disease-modifying osteoarthritis drugs (DMOADs), are required. Several drugs have been reported to attenuate cartilage loss or reduce subchondral bone lesions in OA and thus potentially be DMOADs. Most biologics (including interleukin-1 (IL-1) and tumor necrosis factor (TNF) inhibitors), sprifermin, and bisphosphonates failed to yield satisfactory results when treating OA. OA clinical heterogeneity is one of the primary reasons for the failure of these clinical trials, which can require different therapeutic approaches based on different phenotypes. This review describes the latest insights into the development of DMOADs. We summarize in this review the efficacy and safety profiles of various DMOADs targeting cartilage, synovitis, and subchondral bone endotypes in phase 2 and 3 clinical trials. To conclude, we summarize the reasons for clinical trial failures in OA and suggest possible solutions.

Efficacy of Platelet-Rich Plasma for Chronic Lateral Ankle Instability After Modified Broström-Gould surgery: A Randomized, Single-Blinded, Prospective Controlled Trial

Background

Modified Broström-Gould (MBG) surgery is frequently used for chronic lateral ankle instability (CLAI). However, conventional postoperative management (CPOM) due to prolonged immobilization may have adverse effects on tendons, ligaments, and joints, causing stiffness. This prospective, randomized controlled trial aimed to determine outcomes among patients randomized to receive CPOM plus ultrasonography-guided triple injections of leukocyte-rich platelet-rich plasma (LR-PRP) compared to patients who receive only CPOM after MBG surgery.

Methods

The present study included 40 patients with symptomatic CLAI who were candidates for the MBG surgery. The patients were randomized into 2 groups of 20, the control and PRP groups. In the PRP group, patients were injected with 3 doses of LR-PRP solution using ultrasonographic guidance. In the first injection, 2 mL of LR-PRP was injected near the injury site, and in the second and third injections, 4 mL of LR-PRP was injected in the tibiotalar joint. All patients received a short leg splint for 2 weeks, followed by 4 weeks in a walking boot. The primary outcome measure was the visual analog scale (VAS), and the secondary outcome measures were the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale and ankle total range of motion (total ROM). The assessment was performed at baseline and 3 and 6 months after surgery.

Results

The mean VAS and AOFAS scores improved significantly in both groups 6 months after surgery (P < .001). However, the PRP group did not significantly improve in VAS or AOFAS scores compared with the control group. No clinically significant difference was observed between the 2 groups regarding the total ROM scores at month 3.

Conclusion

The application of LR-PRP after MBG surgery did not show any superior clinical or functional improvement over CPOM.

Level of Evidence

Level II, prospective randomized trial.

Platelet-Rich Plasma for Intra-articular Injections: Preclinical and Clinical Evidence

The use of platelet-rich plasma (PRP) has been supported by encouraging data from in vitro and preclinical in vivo studies, both in terms of safety and efficacy. This led to the wide use of PRP injections in the clinical practice, with promising results especially as a minimally invasive treatment for cartilage degeneration and osteoarthritis (OA). While many controversies remain on the best PRP formulation, the overall available clinical studies support the benefits of PRP, with functional improvement and reduction of pain-related symptoms up to 12 months, especially in young patients and early OA stages.

Extracellular Vesicle Isolation and Characterization for Applications in Cartilage Tissue Engineering and Osteoarthritis Therapy

Extracellular vesicles (EVs) have the capacity for use in cartilage tissue engineering by stimulating tissue repair and microenvironmental reprogramming. This makes them ideal candidates for treating focal cartilage defects and cartilage degeneration in osteoarthritis (OA). Observational studies have reported beneficial biological effects of EVs, such as inhibition of inflammation, enhanced extracellular matrix deposition, and reduced cartilage degradation. Isolation of EVs derived from different source materials such as conditioned cell culture media or biofluids is essential to attribute observed biological effects to EVs as genuine effectors. This chapter presents a density- and a size-based method as well as a combination of both for isolation of EVs from conditioned cell culture media or biofluids. In addition, three methods for characterization of isolated EVs are suggested based on physical properties, protein profiling, and ultrastructural morphology.

Advances in the Treatment of Partial-Thickness Cartilage Defect

Partial-thickness cartilage defects (PTCDs) of the articular surface is the most common problem in cartilage degeneration, and also one of the main pathogenesis of osteoarthritis (OA). Due to the lack of a clear diagnosis, the symptoms are often more severe when full-thickness cartilage defect (FTCDs) is present. In contrast to FTCDs and osteochondral defects (OCDs), PTCDs does not injure the subchondral bone, there is no blood supply and bone marrow exudation, and the nearby microenvironment is unsuitable for stem cells adhesion, which completely loses the ability of self-repair. Some clinical studies have shown that partial-thickness cartilage defects is as harmful as full-thickness cartilage defects. Due to the poor effect of conservative treatment, the destructive surgical treatment is not suitable for the treatment of partial-thickness cartilage defects, and the current tissue engineering strategies are not effective, so it is urgent to develop novel strategies or treatment methods to repair PTCDs. In recent years, with the interdisciplinary development of bioscience, mechanics, material science and engineering, many discoveries have been made in the repair of PTCDs. This article reviews the current status and research progress in the treatment of PTCDs from the aspects of diagnosis and modeling of PTCDs, drug therapy, tissue transplantation repair technology and tissue engineering ("bottom-up").

Intra-articular injections of platelet-rich plasma decrease pain and improve functional outcomes than sham saline in patients with knee osteoarthritis

PURPOSE

To compare the long-term clinical efficacy provided by intra-articular injections of either Pure Platelet-rich Plasma (P-PRP) or sham saline to treat knee osteoarthritis (KOA).

METHODS

This prospective, parallel-group, double-blind, multi-center, sham-controlled randomized clinical trial recruited participants with KOA from orthopedic departments at nine public hospitals (five tertiary medical centers, four secondary medical units) starting January 1, 2014, with follow-up completed on February 28, 2021. Participants were randomly allocated to interventions in a 1:1 ratio. Data were analyzed from March 1, 2021, to July 15, 2021. Three sessions (1 every week) of P-PRP or sham saline injected by physicians. The primary outcome was the Western Ontario and McMaster Universities Arthritis Index (WOMAC) at 3, 6, 12, 24, 60 months of follow-up. Secondary outcomes included the International Knee Documentation Committee (IKDC) subjective score, visual analogue scale (VAS) score, intra-articular biochemical marker concentrations, cartilage volume, and adverse events. Laboratory of each hospital analyzed the content and quality of P-PRP.

RESULTS

610 participants (59% women) with KOA who received three sessions of P-PRP (n = 308, mean age 53.91 years) or sham saline (n = 302, mean age 54.51 years) injections completed the trial. The mean platelet concentration in PRP is 4.3-fold (95% confidence interval 3.6-4.5) greater than that of whole blood. Both groups showed significant improvements in IKDC, WOMAC, and VAS scores at 1 month of follow-up. However, only the P-PRP group showed a sustained improvement in clinical outcome measurements at month 24 (P < 0.001). There were statistically significant differences between the P-PRP and sham saline groups in all clinical outcome measurements at each follow-up time point (P < 0.001). The benefit of P-PRP was clinically better in terms of WOMAC-pain, WOMAC-physical function and WOMAC-total at 6, 12, 24, and 60 months of follow-up. No clinically significant differences between treatments were documented in terms of WOMAC-stiffness at any follow-up. A clinically significant difference favoring P-PRP group against saline in terms of IKDC and VAS scores was documented at 6, 12, 24 and 60 months of follow-up. At 6 months after injection, TNF-α and IL-1β levels in synovial fluid were lower in the P-PRP group (P < 0.001). Tibiofemoral cartilage volume decreased by a mean value of 1171 mm³ in the P-PRP group and 2311 mm³ in the saline group over 60 months and the difference between the group was statistically significant (intergroup difference, 1140 mm³, 95% CI - 79 to 1320 mm³; P < 0.001).

CONCLUSIONS

In this randomized clinical trial of patients with KOA, P-PRP was superior to sham saline in treating KOA. P-PRP was effective for achieving at least 24 months of symptom relief and slowing the progress of KOA, with both P-PRP and saline being comparable in safety profiles.

Intra-articular platelet-rich plasma injection versus hydrocortisone with local anesthetic injections for temporo mandibular disorders

Disorders of temporomandibular joint (TMDs) are characterised by a variety of symptoms, including discomfort in the orofacial region, muscle tenderness, restricted jaw motion and noise at the joint. Additional neurological symptoms such as headaches, vertigo, heaviness, and altered vision may also coexist with TMDs. Because prostaglandin production is a critical mediator of inflammatory reaction and is inhibited by corticosteroids, they have anti-inflammatory effects. Platelet rich plasma popularly considered as PRP is a concentration of platelets and related growth factors that may have therapeutic effects by attracting, promoting, and differentiating cells as well as redesigning tissue. 64 joints totaling 40 individuals with temporomandibular joint problems were split into two categories (Category A and Category B). PRP was applied to category A's (36 joints of 20 patients) joints, while Group B's joints received hydrocortisone combined with local anaesthetic (28 joints of 20 patients). Patients were evaluated for tenderness, , maximum inter incisal opening (MIO) and clicking sound at TMJ prior to and following treatment at intervals of one week, one month and 6 months of the first week and third month. When there was comparison of outcomes in study participants receiving injections of platelet rich plasma and study participants receiving injections of hydrocortisone with local anesthetic then it was found that although both type of study participants got reduction in pain, increased opening of mouth and reduction in clicking sound however the difference between two groups was not significant statistically. There was no statistically significant difference between injections of platelet rich plasma and hydrocortisone with local anesthetic solution regarding outcomes in disorders of temporomandibular joint, however the results were slightly better in study participants receiving platelet rich plasma injections. This study demonstrated that while treating patients with TMJ issues, local anaesthesia combined with hydrocortisone as well as intra-articular injection of PRP help in reduction in pain, increase mouth opening, and minimize joint sound. Additionally, it was discovered that intra-articular injection of PRP was more successful in treating patients in this trial than local anaesthetic combined with hydrocortisone.

Can platelet-rich plasma enhance the effect of meniscus repair? A meta-analysis of randomized controlled trials Platelet-rich plasma and meniscus repair

BACKGROUND

Studies have shown that platelet-rich plasma (PRP) can enhance the effect of meniscus repair, but some studies have suggested different views on the role of PRP.

PURPOSE

To determine whether PRP can enhance the effect of meniscus repair with respect to pain reduction and improved functionality and cure rate in patients with meniscus injury.

METHODS

By searching PubMed, EMBASE, Cochrane Library databases, clinicaltrials.gov, and the CNKI database from their inception till December 1, 2020, we performed a meta-analysis of RCTs reporting the results of the Pain Visual Analog Scale (VAS), the pain of Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score, the International Knee Documentation Committee (IKDC), healing rate, and adverse events. The risk of bias is assessed using Cochrane's collaborative tools. The summary results are expressed with effect size and 95% confidence interval, and sensitivity were performed.

RESULTS

The meta-analysis included 9 RCTs and 345 patients. In general, compared with the control group, used of PRP during meniscus surgery significantly improved the pain (SMD: -0.95, p < 0.00001,95% CI: -1.22 to -0.69, I2 = 42%) and knee joint function (SMD: 1.00, p = 0.01.95% CI: 0.22 to 1.79, I2 = 89%) of patients with meniscus injury at 6 months after treatment. However, both PRP and non-PRP showed improvements in the pain and knee joint function, with no significant difference between the groups at 1 months and beyond 12 months. The PRP enhancement technique showed benefit in improving the cure rate of meniscus repair (RR:1.44; p < 0.0001, 95% CI: 1.20-1.73). No serious adverse events were reported in any study.

CONCLUSION

As an enhancement program for meniscus repair, PRP is worthy of further consideration in improving the function and pain of patients during the mid-term follow-up after surgery, and PRP can further improve the healing rate of meniscus repair. However, the evidence still needs to be interpreted carefully because of the quantity and quality of the included studies.

Platelet-rich plasma use in meniscus repair treatment: a systematic review and meta-analysis of clinical studies

Background

There is conflicting clinical evidence whether platelet-rich plasma (PRP) therapies could translate to an increased meniscus healing rate and improved functional outcomes. The objective of this systematic review and meta-analysis was to compare the failure rate and patient-reported functional outcomes in meniscus repair augmented with and without PRP.

Methods

We comprehensively searched the PubMed, Web of Science, Medline, Embase, and Cochrane Library databases to identify studies that compared the clinical efficacy of meniscus repair performed with PRP versus without PRP. The primary outcome was the meniscus repair failure rate, while the secondary outcomes were knee-specific patient-reported outcomes, including the International Knee Documentation Committee (IKDC) score, Lysholm knee scale, visual analog scale, Tegner activity level score, Western Ontario and McMaster Universities Osteoarthritis Index score, Single Assessment Numeric Evaluation score, and Knee injury and Osteoarthritis Outcome Score. Furthermore, subgroup analyses were performed by stratifying the studies according to the PRP preparation technique to investigate the potential sources of heterogeneity among studies.

Results

Our meta-analysis included nine studies (two RCTs and seven non-RCTs) with 1164 participants. The failure rate in the PRP group was significantly lower than that in the non-PRP group [odds ratio: 0.64, 95% confidence interval (CI) (0.42, 0.96), P = 0.03]. Furthermore, the PRP group was associated with a statistically significant improvement in the visual analog scale for pain [Mean difference (MD): − 0.76, 95% CI (− 1.32, − 0.21), P = 0.007] and Knee injury and Osteoarthritis Outcome Score-symptom [MD: 8.02, 95% CI (2.99, 13.05), P = 0.002] compared with the non-PRP group. However, neither the IKDC score nor the Lysholm knee scale showed any differences between the two groups. In addition, the results of subgroup analyses favored PRP over platelet-rich fibrin matrix (PRFM) regarding the IKDC score.

Conclusions

Although meniscus repairs augmented with PRP led to significantly lower failure rates and better postoperative pain control compared with those of the non-PRP group, there is insufficient RCT evidence to support PRP augmentation of meniscus repair improving functional outcomes. Moreover, PRP could be recommended in meniscus repair augmentation compared with PRFM. PRFM was shown to have no benefit in improving functional outcomes.

Albumin as a Biomaterial and Therapeutic Agent in Regenerative Medicine

Albumin is a constitutional plasma protein, with well-known biological functions, e.g., a nutrient for stem cells in culture. However, albumin is underutilized as a biomaterial in regenerative medicine. This review summarizes the advanced therapeutic uses of albumin, focusing on novel compositions that take advantage of the excellent regenerative potential of this protein. Albumin coating can be used for enhancing the biocompatibility of various types of implants, such as bone grafts or sutures. Albumin is mainly known as an anti-attachment protein; however, using it on implantable surfaces is just the opposite: it enhances stem cell adhesion and proliferation. The anticoagulant, antimicrobial and anti-inflammatory properties of albumin allow fine-tuning of the biological reaction to implantable tissue-engineering constructs. Another potential use is combining albumin with natural or synthetic materials that results in novel composites suitable for cardiac, neural, hard and soft tissue engineering. Recent advances in materials have made it possible to electrospin the globular albumin protein, opening up new possibilities for albumin-based scaffolds for cell therapy. Several described technologies have already entered the clinical phase, making good use of the excellent biological, but also regulatory, manufacturing and clinical features of serum albumin.

Improved biological performance of human cartilage-derived progenitors in platelet lysate xenofree media in comparison to fetal bovine serum media

Primary articular cartilage-derived cells are among the preferred contenders for cell-based therapy approaches for cartilage repair. Limited access to primary human cartilage tissue necessitates the process of in vitro cell expansion to obtain sufficient cells for therapeutic purposes. Therapeutic outcomes of such cell-based approaches become highly dependent on the quality of the in vitro culture-expanded cells. The objective of this study was to determine the differential biological effects of human platelet lysate (hPL) xeno-free defined media vs FBS containing traditional media on primary human cartilage-derived cells. Our goal in pursuing this work was to identify a preferred xenofree media alternative, that can be used as a platform for expansion of cells intended for clinical applications. Primary cartilage-derived cells obtained from five patients were simultaneously cultured in two expansion media's: (1) traditional (DMEM+10%FBS+1%P/S) and (2) defined xenofree (Nutristem® complete media+0.5%hPL). Connective tissue progenitors (CTPs) were assayed by standard colony forming unit assay, morphology, proliferation in early and late passages, expression of MSC associated cell-surface markers (CD73, CD90 and CD105) and trilineage differentiation (adipogenesis, osteogenesis and chondrogenesis) were considered for comparison of biological performance. Early biological performance of primary cartilage-derived cells was significantly improved in Nutristem® expansion media in comparison to traditional expansion media with respect to (1) Colony forming efficiency tended to be higher (p = 0.058) and (2) CTPs formed larger colonies with respect to total cells per colony and colony area (p < 0.01). In the culture expanded cell population, Nutristem® expansion media was superior to traditional expansion media with respect to: (1) overall proliferation rate through passages 1-4 (p = 0.027), (2) total cells harvested at end of passage 4 (p = 0.028) and (3) total positive stain area of CD73 (p = 0.006), CD90 (p = 0.001) and CD105 (p = 0.049). Nutristem®-hPL expanded cells when differentiated in respective xenofree serum-free defined MSCgo™ differentiated media's, also showed significant improvement in adipogenic, osteogenic and chondrogenic marker expression. Overall, we convincingly demonstrated that a low concentration of hPL in combination with defined xenofree media is an effective and economic growth supplement to culture expand primary cartilage-derived cells. It can be manufactured under cGMP conditions to improve clinical-grade cell products' quality for therapeutic applications.

Effect of platelet-rich plasma on meniscus repair surgery: A meta-analysis of randomized controlled trials

BACKGROUND

Studies have shown that platelet-rich plasma (PRP) can enhance the effect of meniscus repair, but some studies have suggested different views on the role of PRP. Therefore, a meta-analysis was conducted to determine whether PRP can enhance the effect of meniscus repair with respect to pain reduction and improved functionality and cure rate in patients with meniscus injury.

METHODS

PubMed, EMBASE, Cochrane Library Databases, clinicaltrials.gov, and the CNKI Database were searched from their inception till December 1, 2020. The RCTs reporting the outcomes of the Pain Visual Analog Scale (VAS), Lysholm score, healing rate, and adverse events were included. The risk of bias was assessed using Cochrane collaborative tools. The simulated results were expressed with effect size and 95% confidence interval, and sensitivity and subgroup analysis were performed.

RESULTS

The meta-analysis included 8 RCTs and 431 participants. Compared with the control group, use of PRP during meniscus surgery significantly improved the VAS (SMD: -0.40, P = .002, 95%CI: -0.66 to -0.15) and Lysholm score (MD: 3.06, P < .0001, 95%CI: 1.70-4.42) of meniscus injury, but the PRP showed no benefit in improving the healing rate of meniscus repair (RR: 1.22, P = .06, 95%CI: 0.99-1.51). No serious adverse events were reported in any study.

CONCLUSIONS

PRP is safe and effective in improving the effect of meniscus repair as augment. High quality RCTs with long follow-up and definitive results are needed in the future to confirm the use and efficacy of PRP in meniscus tears.

Does Bone Marrow Edema Influence the Clinical Results of Intra-Articular Platelet-Rich Plasma Injections for Knee Osteoarthritis?

Platelet-rich plasma (PRP) is increasingly used for the intra-articular treatment of knee osteoarthritis (OA). However, clinical studies on PRP injections reported controversial results. Bone marrow edema (BME) can cause symptoms by affecting the subchondral bone and it is not targeted by intra-articular treatments. The aim of this study was to investigate if the presence of BME can influence the outcome of intra-articular PRP injections in knee OA patients. A total of 201 patients were included in the study, 80 with and 121 without BME at the baseline MRI. BME area and site were evaluated, and BME was graded using the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Patients were assessed with International Knee Documentation Committee (IKDC) score Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, the EuroQol-Visual Analogue Scale (EQ-VAS), and the Tegner score at baseline, 2, 6, and 12 months. Overall, the presence of BME did not influence the clinical results of intra-articular PRP injections in these patients treated for knee OA. Patients with BME presented a similar failure rate and clinical improvement after PRP treatment compared to patients without BME. The area and site of BME did not affect clinical outcomes. However, patients with a higher BME grade had a higher failure rate.

The Clinical Efficacy of Platelet-Rich Plasma versus Conventional Drug Injection in the Treatment of Knee Osteoarthritis: A Study Protocol for a Randomized Controlled Trial

Knee osteoarthritis is a common chronic degenerative joint disease in middle-aged and elderly people. Intra-articular injection for the treatment of knee osteoarthritis is a regularly utilized nonsurgical treatment in modern medicine. Hyaluronic acid (HA) and platelet-rich plasma (PRP) are two frequently employed intra-articular devices. Hyaluronic acid (HA) is an accepted nonsurgical treatment for symptomatic KOA, and platelet-rich plasma is a popular option in the treatment of KOA in recent years. The purpose of this research is to compare the efficacy and safety of intra-articular injection of platelet-rich plasma (PRP) versus hyaluronic acid (HA) on the pain score scale, knee function, and related inflammatory biomarkers in KOA patients using a clinical randomized controlled trial. Participants are being randomized into either the hyaluronic acid (HA) or into the platelet-rich plasma (PRP) group. All patients receive 4 weeks of treatment (once a week), and well-being support and quadriceps training (3 times a week). The primary outcomes are measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the visual analog scale (VAS). The secondary outcomes include the activities of daily living score, erythrocyte sedimentation rate, C-reactive protein testing, interleukin-6 levels, and X-ray examination. In order to monitor the occurrence of irregularities and abnormalities, patients are assessed at each visit, and restorative treatment is given if necessary. The results of this clinical trial will verify the efficacy of PRP and HA in the treatment of KOA and provide important evidence for the clinical treatment of KOA. The trial was enlisted at the Chinese Clinical Trial Registry on 26 September 2020 (ChiCTR2000038635).

The effectiveness of leucocyte-poor platelet-rich plasma injections on symptomatic early osteoarthritis of the knee: the PEAK randomized controlled trial

AIMS

Platelet-rich plasma (PRP) intra-articular injections may provide a simple and minimally invasive treatment for early-stage knee osteoarthritis (OA). This has led to an increase in its adoption as a treatment for knee OA, although there is uncertainty about its efficacy and benefit. We hypothesized that patients with early-stage symptomatic knee OA who receive multiple PRP injections will have better clinical outcomes than those receiving single PRP or placebo injections.

METHODS

A double-blinded, randomized placebo-controlled trial was performed with three groups receiving either placebo injections (Normal Saline), one PRP injection followed by two placebo injections, or three PRP injections. Each injection was given one week apart. Outcomes were prospectively collected prior to intervention and then at six weeks, three months, six months, and 12 months post-intervention. Primary outcome measures were Knee Injury and Osteoarthritis Outcome Score (KOOS) and EuroQol five-dimension five-level index (EQ-5D-5L). Secondary outcomes included visual analogue scale for pain and patient subjective assessment of the injections.

RESULTS

A total of 102 patients were recruited. The follow-up period was 12 months, at intervals of six weeks, 12 weeks, six months, and 12 months. KOOS-Total significantly improved in all groups at these time intervals compared to pre-injection. There was an improvement in EQ-5D-5L index scores in saline and single injection groups, but not in the multiple injection group. Comparison of treatment groups showed no additional beneficial effect of single or multiple PRP injections above that displayed in the saline injection group. Subjective patient satisfaction and recommendation of treatment received demonstrated a similar pattern in all the groups. There was no indication of superiority of either single or multiple PRP injections compared to saline injections.

CONCLUSION

There is no evidence that single or multiple PRP had any additional beneficial effect compared to saline injection up to 12 months, follow-up after treatment of early stage symptomatic OA of the knee. Cite this article: Bone Joint J 2022;104-B(6):663-671.

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.

Clinical Response After Treatment of Knee Osteoarthritis With a Standardized, Closed-System, Low-Cost Platelet-Rich Plasma Product: 1-Year Outcomes

Background:

Intra-articular infiltration of platelet-rich plasma (PRP) is an alternative therapeutic option to classic hyaluronic acid for the treatment of symptomatic knee osteoarthritis (KOA). However, variation in preparation methods and quality assessment of PRP makes the study of its real clinical efficacy difficult.

Purpose:

To (1) evaluate the clinical efficacy of a characterized PRP product prepared in a standardized manner and in a closed-system for the treatment of KOA and to (2) evaluate the association of the clinical response to PRP-related variables.

Study Design:

Case series; Level of evidence, 4.

Methods:

We recruited 130 patients with nonoperative KOA and evaluated them for 1 year. PRP was prepared from a donation of autologous blood, obtaining 3 aliquots of approximately 10mL of product, which were frozen, allowing platelet disruption, platelet factor release, and long-term storage, until administration. Patients were treated 3 consecutive times every 4 weeks with an intra-articular PRP knee injection under sterile conditions. Complete blood count was performed on the whole-blood sample and the processed PRP before freezing it, for product quality assessment. Patients were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and basic satisfaction scale at 3 months, 6 months, and 1 year after intervention.

Results:

Quality assessment confirmed a leukocyte-poor PRP product (white blood cell count, 0.09 ± 0.09 × 10⁹/L) with a high platelet purity (platelet count, 630.86 ± 191.75 × 10⁹/L). WOMAC scores improved, and basic satisfaction was achieved in 70% of patients. No adverse events were reported. No correlations were observed between PRP quality parameters and clinical results. PRP complete treatment production costs were €108/US$125 (€36/US$41.6 per injection).

Conclusion:

This standardized PRP production method resulted in improved WOMAC scores at 1 year postoperatively in 70% of patients with KOA. This technique was safe and affordable and ensured consecutive infiltrations with the same product to each patient.

Influence of Sexual Dimorphism, Aging, and Differential Cell Capture Efficiency of Blood Separation Systems on the Quality of Platelet-Rich Plasma

Few studies have checked the impact of the hormonal/immunological dimorphism of patients on the cellular composition of platelet-rich plasma products (PRP). Whole blood (WB) from 26 volunteers was concentrated using a device previously characterized. Platelet and white blood cell (WBC) counts in WB and PRP were compared between genders, and after the population was split into pre (≤50 years)- and post (>50 years)-menopausal ages. In WB, platelet−total WBC densities were comparable in men and women. The phagocytic cell composition differed (p ≤ 0.04). After dividing by ages, phagocytic cell discrepancies were linked to women > 50 years (p ≤ 0.05), and differences emerged in lymphocyte counts (lower in >50 years groups, within and between genders, p ≤ 0.05). In PRP, densities were significantly higher, but the PRP/WB ratios varied according to blood cell (lower for phagocytic cells) and between subjects (more favorable at a lower density of a particular blood cell in WB). This “system compensatory efficiency” reduced/reverted PRP differences in the leukocyte composition between genders/age−sex groups in WB. In PRP, neutrophils were higher in younger men than older women (p < 0.05). WB lymphocyte differences between age−sex groups persisted. Age is a more determining factor than sex in the preparation of PRP. Post-menopause, sexual dimorphism strongly influences the composition of leukocytes, also conditioned by the capture efficiency of the system.

The Effect of Leukocyte Concentration on Platelet-Rich Plasma Injections for Knee Osteoarthritis: A Network Meta-Analysis

BACKGROUND

It is hypothesized that leukocyte-poor (LP) platelet-rich plasma (PRP) is preferred over leukocyte-rich (LR) PRP for the treatment of knee osteoarthritis (OA).

METHODS

The MEDLINE, Embase, and Cochrane databases were reviewed for all English-language studies comparing LP-PRP or LR-PRP with relevant controls or each other. The follow-up periods were 6 months and 12 months. The primary outcome measure was the change in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between baseline and follow-up. The secondary outcome measures were changes in the WOMAC pain subscale, visual analog scale (VAS) for pain, and International Knee Documentation Committee (IKDC) subjective score between baseline and follow-up, and the incidence of local adverse reactions. Treatment outcomes were analyzed using the mean difference between treatments for continuous outcomes and the odds ratio for binary outcomes, with 95% credibility intervals. Treatment modalities were ranked using the surface under the cumulative ranking (SUCRA) probabilities. Risk of bias was assessed using the relevant Cochrane tools, RoB 2 (version 2 of the Cochrane risk-of-bias tools) for randomized controlled trials (RCTs) and ROBINS-I (Risk of Bias in Non-Randomized Studies - of Interventions) for prospective comparative studies (PCSs).

RESULTS

This network meta-analysis included 23 studies: 20 RCTs and 3 PCSs, with a total of 2,260 patients and a mean follow-up period of 9.9 months. The overall risk-of-bias assessment of the RCTs revealed that 9 studies had low risk, 7 had some concerns, and 4 had high risk. The overall risk-of-bias assessment of the PCSs revealed that 1 study had low risk and 2 had moderate risk. We found no significant (p < 0.05) difference in all outcome measures and local adverse reactions between LP-PRP and LR-PRP. SUCRA rankings revealed that, for all outcome measures, LP-PRP is preferred to LR-PRP across follow-up periods.

CONCLUSIONS

Leukocyte concentration of PRP does not play a significant role in patient-reported outcome measures for knee OA. LP-PRP is preferred to LR-PRP according to SUCRA rankings, but this preference may not be important in clinical practice.

LEVEL OF EVIDENCE

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

Influential Studies in Orthopaedic Platelet-Rich Plasma Research Are Recent and Consist of High Levels of Evidence: A Review of the Top 50 Most Cited Publications

Platelet-rich plasma (PRP) has garnered widespread and increasing attention in recent years. We aimed to characterize the most influential articles in PRP research while clarifying controversies surrounding its use and clinical efficacy and identifying important areas on which to focus future research efforts. The Science Citation Index Expanded subsection of the Web of Science Core Collection was systematically searched to identify the top 50 cited publications on orthopedic PRP research. Publication and study characteristics were extracted, and Spearman's correlations were calculated to assess the relationship between citation data and level of evidence. The top 50 articles were published between the years 2005 and 2016, with 68% published in the year 2010 or later. Of the 33 studies for which level of evidence was assessed, the majority were of level I or II (18, 54.5%). Seventeen articles (34%) were classified as basic science. All clinical studies were prospective, and most (12 studies, 60%) included a high number of metrics related to the PRP preparation protocol and composition. Knee osteoarthritis was the most common topic among clinical studies in the top 50 cited articles (11 studies, 34%). More recent articles were associated with higher citation rates (ρ = 0.46, p < 0.001). The most influential articles on orthopaedic PRP research are recent and consist of high-level of evidence studies mostly. Randomized controlled trials were the most common study type, while basic science articles were relatively less common. The most influential clinical studies reported a high number of metrics related to their PRP preparation protocol and the final PRP composition. These results suggest a rapidly evolving field with the potential to better explain inconsistent clinical results with improved understanding and documentation of basic science concepts such as PRP composition, preparation, and combination techniques.

Leukocyte-Rich versus Leukocyte-Poor Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis: A Double-Blind Randomized Trial

BACKGROUND

Platelet-rich plasma (PRP) is gaining large interest in clinical practice as a minimally invasive injective treatment for knee osteoarthritis (OA). Different preparation methods are available, and the presence of leukocytes, deemed detrimental in some preclinical studies, is one of the most debated aspects regarding PRP efficacy.

PURPOSE

To compare the safety and effectiveness of leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) for the treatment of knee OA.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 192 patients with symptomatic knee OA (Kellgren-Lawrence grade 1-3) were randomly allocated to 3 weekly injections of LR-PRP or LP-PRP. LP-PRP was obtained with a filter for leukodepletion. LR-PRP and LP-PRP were divided into aliquots of 5 mL, with a mean platelet concentration of 1146.8 × 10⁹/L and 1074.9 × 10⁹/L and a mean leukocyte concentration of 7991.4 × 10⁶/L and 0.1 × 10⁶/L, respectively. Patients were evaluated at baseline and thereafter at 2, 6, and 12 months for the primary outcome, the International Knee Documentation Committee (IKDC) subjective score; and for secondary outcomes, the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, EuroQol-visual analog scale (EQ-VAS), and Tegner score.

RESULTS

No differences between groups were observed in terms of absolute values or improvement of the clinical scores across all follow-up intervals. The mean IKDC subjective score at baseline and 12 months improved from 45.6 to 60.7 in the LR-PRP group as compared with 46.8 to 62.9 in the LP-PRP group (P = .626). No severe adverse events were described in either group, although 15 mild adverse events (knee pain or swelling) were reported: 12.2% for LR-PRP and 4.7% for LP-PRP (P = .101). No statistically significant difference was also found between LR-PRP and LP-PRP in terms of failures (7.8% vs 3.5%, P = .331).

CONCLUSION

This double-blind randomized trial showed that 3 intra-articular LR-PRP or LP-PRP injections produced similar clinical improvement in the 12 months of follow-up in patients with symptomatic knee OA. Both treatment groups reported a low number of adverse events, without intergroup differences. The presence of leukocytes did not significantly affect the clinical results of PRP injections.

REGISTRATION

NCT02923700 (ClinicalTrials.gov identifier).

Comparisons of Ultrasound-Guided Platelet-Rich Plasma Intra-Articular Injection and Extracorporeal Shock Wave Therapy in Treating ARCO I–III Symptomatic Non-Traumatic Femoral Head Necrosis: A Randomized Controlled Clinical Trial

Background and Objective

Osteonecrosis of the femoral head (ONFH) is a devastating disease, and there is some evidence that extracorporeal shock wave therapy (ESWT) and intra-articular platelet-rich plasma (PRP) injection might alleviate pain and improve joint function in individuals with ONFH. The objective of this study was to compare the effectiveness and safety of PRP and ESWT in symptomatic ONFH patients.

Methods

A total of 60 patients aged 40–79 with unilateral ONFH at Association Research Circulation Osseous (ARCO) stages I, II, and III were randomly assigned to the PRP (N=30) or the ESWT group (N=30). Four treatment sessions were provided in both groups. Assessments were performed at baseline, and 1-, 3-, 6-, and 12-month. Primary outcomes were measured by the visual analogue scale (VAS), and pressure pain thresholds (PPTs). Secondary outcomes were assessed by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), and magnetic resonance imaging (MRI). The linear mixed-model analysis was used to evaluate the differences between groups and within groups and the “group by time” interaction effects.

Results

There were significant differences between groups in terms of changes over time for VAS, PPTs, WOMAC, and HHS since 3-month and maintained up to 12-month (P<0.05, except for PPTs at 12-month). The simple main effects showed that the patients in PRP group had greater improvements in VAS (mean difference = −0.82, 95% CI [−1.39, −0.25], P=0.005), WOMAC (mean difference = −4.19, 95% CI [−7.00, −1.37], P=0.004), and HHS (mean difference = 5.28, 95% CI [1.94, 8.62], P=0.002). No related adverse events were reported.

Conclusion

This study supported the effectiveness and safety of both the PRP injection and ESWT in treating ONFH patients. For symptomatic patients with ONFH, intra-articular PRP injection appeared superior to ESWT in pain relief and functional improvement.

Cytokine Profiling and Intra-Articular Injection of Autologous Platelet-Rich Plasma in Knee Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease leading to joint pain and stiffness. Due to lack of effective treatments, physical and psychological disabilities caused by OA have a detrimental impact on the patient’s quality of life. Emerging evidence suggests that intra-articular injection of platelet-rich plasma (PRP) may provide favorable results since PRP comprises not only a high level of platelets but also a huge amount of cytokines, chemokines, and growth factors. However, the precise mechanism and standardization method remain uncertain. This study aimed to examine cytokine profiling in both PRP and platelet-poor plasma (PPP) of knee OA patients and to determine the effects of PRP on OA chondrocytes and knee OA patients. PRP contained a wide variety of cytokines, chemokines, growth factors, and autologous intra-articular PRP injection resulted in favorable outcomes in knee OA patients. Significant increases in levels of IL-1, IL-2, IL-7, IL-8, IL-9, IL-12, TNF-α, IL-17, PDGF-BB, bFGF, and MIP-1β were detected in PRP compared to PPP (p < 0.001). An in vitro study showed a marked increase in proliferation in OA chondrocytes cultured with PRP, compared to PPP and fetal bovine serum (p < 0.001). In a clinical study, knee OA patients treated with PRP showed improvement of physical function and pain, assessed by physical performance, Western Ontario and McMaster Universities Arthritis Index and visual analog scale. Our findings from both in vitro and clinical studies suggest that intra-articular PRP injection in knee OA patients may be a potential therapeutic strategy for alleviating knee pain and delaying the need for surgery.

PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To evaluate effectiveness, in terms of patient-reported outcome measures, of platelet-rich plasma (PRP) injections for knee osteoarthritis compared to placebo and other intraarticular treatments.

DESIGN

PubMed, Cochrane Library, Scopus, Embase, Web of Science, as well as the gray literature were searched on January 17, 2020. Randomized controlled trials (RCTs) comparing PRP injections with placebo or other injectable treatments, in any language, on humans, were included. Risk of bias was assessed following the Cochrane guidelines; quality of evidence was graded using the GRADE guidelines.

RESULTS

Thirty-four RCTs, including 1403 knees in PRP groups and 1426 in control groups, were selected. WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score favored PRP, with a statistically and clinically significant difference versus placebo at 12-month follow-up (P = 0.02) and versus HA (hyaluronic acid) at 6-month (P < 0.001) and 12-month (P < 0.001) follow-ups. A clinically significant difference favoring PRP versus steroids was documented for VAS (Visual Analogue Scale) pain (P < 0.001), KOOS (Knee Injury and Osteoarthritis Outcome Score) pain (P < 0.001), function in daily activities (P = 0.001), and quality of life (P < 0.001) at 6-month follow-up. However, superiority of PRP did not reach the minimal clinically important difference for all outcomes, and quality of evidence was low.

CONCLUSIONS

The effect of platelet concentrates goes beyond its mere placebo effect, and PRP injections provide better results than other injectable options. This benefit increases over time, being not significant at earlier follow-ups but becoming clinically significant after 6 to 12 months. However, although substantial, the improvement remains partial and supported by low level of evidence. This finding urges further research to confirm benefits and identify the best formulation and indications for PRP injections in knee OA.

Intra-articular Injection of Type I Atelocollagen to Alleviate Knee Pain: A Double-Blind, Randomized Controlled Trial

OBJECTIVE

Collagen disruption is one of the underlying causes of knee pain in patients with osteoarthritis and/or diverse cartilage defects. Atelocollagen is a type of collagen that lacks telopeptides and thus has reduced antigenicity. The intra-articular injection of type I atelocollagen supplements collagen levels in the disrupted articular cartilage. This randomized controlled trial evaluated the effects of the intra-articular injection of atelocollagen for the management of knee pain.

DESIGN

Two hundred patients with osteoarthritis, chondromalacia, or other cartilage defects were randomly assigned to receive a 3-mL intra-articular injection of atelocollagen (BioCollagen group) or saline (Placebo group). Clinical improvement was evaluated over a 24-week period using the 100-mm visual analogue scale (VAS), the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and the 36-item Short-Form Health Survey (SF-36).

RESULTS

VAS scores were significantly better in the BioCollagen group as compared with the Placebo group at 24 weeks. More patients in the BioCollagen group reported exceeding 20% and 40% VAS improvements. The WOMAC and SF-36 scores were also significantly improved from baseline after the intra-articular injection of atelocollagen; although, the differences between the BioCollagen and Placebo groups were not significant. There were no unexpected or severe adverse events reported for either group.

CONCLUSIONS

The results show that an intra-articular injection of atelocollagen effectively alleviates knee pain, as intended. Therefore, the intra-articular injection of atelocollagen can be considered an alternative solution to controlling knee pain due to osteoarthritis and diverse cartilage defects.

Effect of Platelet-Rich Plasma Injections vs Placebo on Ankle Symptoms and Function in Patients With Ankle Osteoarthritis: A Randomized Clinical Trial

IMPORTANCE

Approximately 3.4% of adults have ankle (tibiotalar) osteoarthritis and, among younger patients, ankle osteoarthritis is more common than knee and hip osteoarthritis. Few effective nonsurgical interventions exist, but platelet-rich plasma (PRP) injections are widely used, with some evidence of efficacy in knee osteoarthritis.

OBJECTIVE

To determine the effect of PRP injections on symptoms and function in patients with ankle osteoarthritis.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter, block-randomized, double-blinded, placebo-controlled clinical trial performed at 6 sites in the Netherlands that included 100 patients with pain greater than 40 on a visual analog scale (range, 0-100) and tibiotalar joint space narrowing. Enrollment began on August 24, 2018, and follow-up was completed on December 3, 2020.

INTERVENTIONS

Patients were randomly assigned (1:1) to receive 2 ultrasonography-guided intra-articular injections of either PRP (n = 48) or placebo (saline; n = 52).

MAIN OUTCOMES AND MEASURES

The primary outcome was the validated American Orthopaedic Foot and Ankle Society score (range, 0-100; higher scores indicate less pain and better function; minimal clinically important difference, 12 points) over 26 weeks.

RESULTS

Among 100 randomized patients (mean age, 56 years; 45 [45%] women), no patients were lost to follow-up for the primary outcome. Compared with baseline values, the mean American Orthopaedic Foot and Ankle Society score improved by 10 points in the PRP group (from 63 to 73 points [95% CI, 6-14]; P < .001) and 11 points in the placebo group (from 64 to 75 points [95% CI, 7-15]; P < .001). The adjusted between-group difference over 26 weeks was -1 ([95% CI, -6 to 3]; P = .56). One serious adverse event was reported in the placebo group, which was unrelated to the intervention; there were 13 other adverse events in the PRP group and 8 in the placebo group.

CONCLUSIONS AND RELEVANCE

Among patients with ankle osteoarthritis, intra-articular PRP injections, compared with placebo injections, did not significantly improve ankle symptoms and function over 26 weeks. The results of this study do not support the use of PRP injections for ankle osteoarthritis.

TRIAL REGISTRATION

Netherlands Trial Register: NTR7261.

Photobiomodulation (λ=808nm) and Platelet-Rich Plasma (PRP) for the Treatment of Acute Rheumatoid Arthritis in Wistar Rats

Introduction: Rheumatoid arthritis (RA) causes inflammation, pain, edema, and articular degradation and its treatment can be based on anti-inflammatory drugs, photobiomodulation (PBM) and/or platelet-rich plasma (PRP) that can decrease cell flow and promote local healing. In the present study, we evaluate the effects of PBM and PRP on acute arthritis in Wistar rats through inflammatory and oxidative stress parameters. Methods: Thirty female Wistar rats were assigned to five groups (n=6, each group): Control, Sham, PRP, Laser, and PRP+Laser. For arthritis induction, all animals of groups Sham, PRP, Laser and PRP+Laser received an intraarticular injection of Zymosan® (200µg) in the right knee. Twenty-four hours post-arthritis induction, PRP was prepared and injected (8 × 105 of platelets) in animals of PRP and PRP+Laser groups. PBM was performed in Laser and PRP+Laser groups by single-dose therapy with the GaAlAs laser (λ=808 nm, P=25 mW, fluence=30 J/cm2, beam area=0.02 mm2, t=33 seconds, E=0.825 J, punctual application). After seven days of induction, serum samples were collected and thiobarbituric acid reactive substances (TBARS), nitric oxide (NO) and catalase activity were analysed. Morphological parameters were measured for inflammation areas, cartilage thickness, and C3 protein expression in knee samples. Statistical analysis was performed with an ANOVA test and Tukey's post-hoc test with a significance level of 5% (P<0.05). Results: NO was lower in the treated groups compared to the Sham group, and TBARS did not show any differences, while catalase showed greater activity between PRP+Laser versus PRP (P<0.05). Inflammatory areas and cartilage thickness were lower in the treated groups compared to Sham (P<0.05), while no differences in C3 protein expression was observed. Conclusion: PBM associated with PRP is better for anti-inflammatory and joint preservation by morphological aspects and NO levels that concern a potential clinical application.

Canine-Origin Platelet-Rich Fibrin as an Effective Biomaterial for Wound Healing in Domestic Cats: A Preliminary Study

Platelet-rich fibrin (PRF) is a recent platelet-based biomaterial, poised as an innovative regenerative strategy for the treatment of wounds from different etiologies. PRF is defined as a biodegradable scaffold containing elevated amounts of platelets and leukocytes having the capability to release high concentrations of bioactive structural proteins and acting as a temporal release healing hemoderivative. This study aimed to evaluate the performance of canine-origin PRF, obtained from blood of screened donors, as a regenerative biomaterial suitable for the treatment of critical wounds in felines. Four short-hair felines with naturally occurring wounds were enrolled in this study. Three of the wounds were considered infected. Each PRF treatment was the result of the grafting of newly produced PRFs at the recipient area. The PRF treatment was initially performed two to three times per week, followed by single weekly treatments. The study was finalized when complete wound closure was achieved. No topical antimicrobial/antiseptic treatment was applied. The present research demonstrated that xenogenic PRFs significantly induced healthy vascularized granulation tissue in lesions with soft tissue deficit, also prompting the epithelization at the injured site. No rejection, necrosis, or infection signs were recorded. Additionally, PRF-therapy was revealed to be a biological cost-effective treatment, accelerating the wound healing process.

Platelet-Rich Plasma for Bone Fracture Treatment: A Systematic Review of Current Evidence in Preclinical and Clinical Studies

Background: Recently, there is an increasing interest in the therapeutic potential of platelet-rich plasma (PRP) for bone fracture treatment. Nevertheless, the effect of PRP for bone fracture treatment remains controversial and is still a matter of discussion. Therefore, we performed a systematic review to evaluate the efficacy and safety of PRP injection for treatment of bone fracture. Methods: The main bibliographic databases, including Medline, PubMed, Embase, Web of Science, and the Cochrane library, were comprehensively searched for studies focusing on the application of platelet-rich plasma (PRP) on bone fracture treatment. All relevant articles were screened for eligibility and subdivided into the preclinical and clinical studies. Data were extracted and presented systematically. Results: Finally, twenty-six in vitro preclinical studies (basic studies), nine in vivo preclinical studies (animal studies), and nine clinical studies, met the selection criteria, and were included in the present systematic review. Preclinical studies showed an overall positive effect of PRP on osteoblast-like cells in vitro and bone healing in animal models. The most used treatment for bone fracture in animal and clinical studies is fixation surgery combined with PRP injection. The clinical studies reported PRP shortened bony healing duration, and had no positive effect on improving the healing rate of closed fractures. However, the results of functional outcomes are controversial. Additionally, compared with control group, PRP would not increase the rate of postoperative wound infection. Conclusion: The present systematic review confirmed the continuing interests of PRP as an additional treatment for bone fracture. Preclinical studies highlighted the potential value of PRP as promising therapy for bone fracture. However, the preclinical evidence did not translate into a similar result in the clinical studies. In addition, types of fractures and procedures of PRP preparation are heterogeneous in enrolled studies, which might result in controversial results. Meanwhile, characteristics of PRP, such as platelet concentration, the numbers of leukocytes, still need to be determined and further research is required.

Bone marrow mononuclear cells for joint therapy: The role of macrophages in inflammation resolution and tissue repair

Osteoarthritis (OA) is the most prevalent joint disease causing major disability and medical expenditures. Synovitis is a central feature of OA and is primarily driven by macrophages. Synovial macrophages not only drive inflammation but also its resolution, through a coordinated, simultaneous expression of pro- and anti-inflammatory mechanisms that are essential to counteract damage and recover homeostasis. Current OA therapies are largely based on anti-inflammatory principles and therefore block pro-inflammatory mechanisms such as prostaglandin E₂ and Nuclear factor-kappa B signaling pathways. However, such mechanisms are also innately required for mounting a pro-resolving response, and their blockage often results in chronic low-grade inflammation. Following minor injury, macrophages shield the damaged area and drive tissue repair. If the damage is more extensive, macrophages incite inflammation recruiting more macrophages from the bone marrow to maximize tissue repair and ultimately resolve inflammation. However, sustained damage and inflammation often overwhelms pro-resolving mechanisms of synovial macrophages leading to the chronic inflammation and related tissue degeneration observed in OA. Recently, experimental and clinical studies have shown that joint injection with autologous bone marrow mononuclear cells replenishes inflamed joints with macrophage and hematopoietic progenitors, enhancing mechanisms of inflammation resolution, providing remarkable and long-lasting effects. Besides creating an ideal environment for resolution with high concentrations of interleukin-10 and anabolic growth factors, macrophage progenitors also have a direct role in tissue repair. Macrophages constitute a large part of the early granulation tissue, and further transdifferentiate from myeloid into a mesenchymal phenotype. These cells, characterized as fibrocytes, are essential for repairing osteochondral defects. Ongoing “omics” studies focused on identifying key drivers of macrophage-mediated resolution of joint inflammation and those required for efficient osteochondral repair, have the potential to uncover ways for developing engineered macrophages or off-the-shelf pro-resolving therapies that can benefit patients suffering from many types of arthropaties, not only OA.