Multiple platelet-rich plasma injections are superior to single PRP injections or saline in osteoarthritis of the knee: the 2-year results of a randomized, double-blind, placebo-controlled clinical trial

[Blood Products and Stem Cells in Osteoarthritis Therapy]

The principle of regenerative medicine in the treatment of osteoarthritis pursues a functional restoration of cartilage tissue instead of just repairing cartilage defects. The use of blood products is intended to inhibit chronic inflammatory processes and promote tissue regeneration. Intraarticular injection of autologous platelet-rich plasma (PRP) is a prominent procedure. Clinical evidence supports PRP injection over hyaluronic acid or glucocorticoid injection. Comparability of studies is difficult due to missing standardisation of production procedures, dosing and donor variability. In particular, whether presence of residual leukocytes is required or should be avoided is an open debate. In contrast, stem cell therapies in osteoarthritis therapy are often based on mesenchymal stem cells (MSC) from adipose tissue or bone marrow aspirate. Different sources of MSC might render the cells more suitable for application in a given context. Nevertheless, it became evident that their secretome rather than the cells themselves are responsible for observed regenerative processes. Research on the mechanisms of action have focused on growth factors. However, an overlooked component of blood products called extracellular vesicles (EV) came to the center of attention, which are also released by MSC as intercellular signal carriers. EV cargo molecules such as miRNAs open up new dimensions in the investigation and explanation of clinically observed anti-inflammatory and regenerative effects.

Platelet-rich plasma intra-articular knee injections from open preparation techniques do not pose a higher risk of joint infection: A systematic review of 91 randomized controlled trials and 5914 injections

Purpose

To compare the infection rate of intraarticular platelet-rich plasma (PRP) knee injections between open and closed techniques in randomized controlled trials (RCTs) published in the last decade.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, PubMed, Scopus and Virtual Health Library were accessed in October 2022 using the terms 'platelet-rich plasma', 'PRP', 'knee' and 'tibiofemoral' alone and in combination with Boolean operators AND/OR. RCTs published during the last 10 years evaluating PRP intra-articular knee injections were considered eligible. Studies were excluded if the kit/preparation technique was not described. Data were presented using individual studies' absolute values, totals, and pooled percentages. Publication bias was assessed using the ROBIS tool.

Results

Ninety-one studies met the predetermined eligibility criteria. Forty-one implemented a closed technique, while 50 were open. All studies implementing a closed technique disclosed their commercial kits. Only 16 studies (17.58%) failed to report joint infections. Among the studies reporting joint infections as outcomes, 30 implemented a closed technique with 1195 patients, 1921 intra-articular knee injections and 95.44% of patient follow-up. On the other hand, 45 of them implemented an open technique with 2290 patients, 3993 intra-articular knee injections and 97.07% of patient follow-up. No patient had a joint infection among the included studies. Thirty-three studies prepared their PRP in controlled environments (36.26%). Most studies did not report where the preparation occurred (48.35%). Only twelve studies disclosed using laminar flow during preparation (13.19%). The infection rate for both techniques was 0 per 1000 knee injections.

Conclusion

Open PRP preparation techniques do not pose a higher risk of joint infection and can lower manufacturing costs when appropriate facilities are available. However, PRP preparation setting and laminar flow implementation data are deficient, and minimal requirements for good manufacturing practices demand further studies while adhering to local and regional regulations.

Level of Evidence

Level I, systematic review of RCTs.

The varying clinical effectiveness of single, three and five intraarticular injections of platelet-rich plasma in knee osteoarthritis

OBJECTIVE

To investigate the variations in clinical effectiveness among patients diagnosed with knee osteoarthritis who underwent intra-articular administration of platelet-rich plasma using single, triple, or quintuple injections.

METHODS

One hundred twenty patients with grade I-III knee osteoarthritis were randomly assigned to three groups: PRP1 group, who received a single injection of platelet-rich plasma; PRP3 group, who received three PRP injections one week apart; PRP5 group, who received five PRP injections one week apart. The patients' conditions were evaluated using the Visual Analogue Scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index-VA3.1 version (WOMAC-VA3.1) at baseline and 6, 12, 24, and 52 weeks 52 weeks follow up.

RESULTS

Out of the total participants, 106 patients (30 males and 76 females) completed the study. The primary outcome measure, WOMAC pain score, registered significant improvements across all groups when compared to pre-treatment levels. However, the application of 3 and 5 injections of platelet-rich plasma was substantially more effective than that of a single injection in reducing knee pain and stiffness, as well as enhancing physical function in patients with knee osteoarthritis. No statistically discernable difference was observed between PRP3 and PRP5 at all follow-up intervals, and there was no discernable difference between 3 and 5 PRP injections either. Mild side effects occurred in all three groups.

CONCLUSIONS

The administration of three or five injections of platelet-rich plasma is safe, substantially more effective than single injections, and leads to remarkable clinical improvement by significantly reducing knee pain, improving joint stiffness, and enhancing physical function in patients with grade I-III knee osteoarthritis. Furthermore, no significant difference was observed in the efficacy of three or five injections. Therefore, we recommend using three injections of PRP in the treatment of patients with knee osteoarthritis of grade I-III.

Randomized Controlled Trials on Platelet-Rich Plasma for Knee Osteoarthritis Poorly Adhere to the Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO) Guidelines: A Systematic Review

BACKGROUND

Platelet-rich plasma (PRP) treatment for knee osteoarthritis has grown exponentially over the past decade; however, its scientific evaluation is highly variable. The American Academy of Orthopaedic Surgeons addressed the need for the standardization of orthobiologics studies by publishing the Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO) guidelines in May 2017. In total, the MIBO guidelines are divided into 12 categories, encompassing 23 checklist items.

HYPOTHESIS/PURPOSE

The purpose of this study was to analyze how well randomized controlled trials (RCTs) on PRP interventions for knee osteoarthritis adhered to the MIBO guidelines. We hypothesized that most articles would report <80% of the MIBO criteria.

STUDY DESIGN

Systematic review; Level of evidence, 1.

METHODS

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were used to perform a systematic review in the PubMed/MEDLINE and Web of Science databases. Inclusion criteria included English-language RCTs that assessed PRP interventions for knee osteoarthritis and reported beginning patient enrollment in June 2017 or later. The original 23 MIBO checklist items were separated and modified into a 44-point checklist. Adherence was determined by calculating the total percentage of checklist items that each article adequately and clearly reported from the 44-point checklist.

RESULTS

A total of 25 RCTs (2356 patients) were included in this study. The weighted mean age was 57.7 ± 4.4 years, with 42.9% being male. On average, only 53.1% ± 10.4% (range, 31.8%-77.3%) of the 44-point MIBO checklist items were reported per article. No articles had adherence rates ≥80%, 5 (20.0%) had rates between 60% and 79.9%, and 20 (80.0%) had rates ≤59.9%. Categories fluctuated in adherence, with "Intervention" having the greatest adherence (100.0%) and "Activation" having the lowest (14.0%). Additionally, 4 (33.3%) categories had adherence rates ≥80%, 0 had rates from 60% to 79.9%, and 8 (66.7%) had rates ≤59.9%.

CONCLUSION

The overall mean adherence to MIBO guidelines by RCTs on PRP interventions for knee osteoarthritis was 53.1%. To increase the reproducibility, improve transparency, and assess the treatment efficacy of future PRP studies, reporting of MIBO guidelines should be improved.

Inadequate anticoagulation and hyperuricemia cause knee pain after platelet-rich plasma injection: A retrospective study

OBJECTIVES

Platelet-rich plasma treatment delays the need for total knee replacement in patients with knee osteoarthritis. However, its use and preparation remain controversial. The aim of this study was to investigate the relationship between anticoagulant use in the preparation of platelet-rich plasma and post-treatment pain in patients with knee osteoarthritis. Additionally, we explored the efficacy of platelet-rich plasma over medium- and long-term follow-up periods and identified other factors that may affect treatment outcomes.

METHODS

In this retrospective study, 225 patients with knee osteoarthritis, who underwent knee platelet-rich plasma treatment from June 2021 to January 2022, were examined at three study centres. Patients were categorised, based on the type and amount of anticoagulant used during platelet-rich plasma preparation, into 4% sodium citrate (SC) 0.6 mL, 4% SC 1 mL, 4% SC 2 mL, heparin 0.1 mL, and heparin 0.2 mL groups. We analysed the patients' basic information, pain after treatment, and inflammatory markers (i.e., interleukin 6, tumour necrosis factor-α, and hypersensitive C-reactive protein) in the joint fluid via enzyme-linked immunosorbent assay and joint fluid crystallisation. Additionally, we assessed the patients' Western Ontario and McMaster University scores and minimal clinically significant differences after treatment.

RESULTS

Patients in the 4% SC 0.6 mL and heparin 0.1 mL groups experienced less pain after platelet-rich plasma treatment than did patients in the high-dose anticoagulant group. The joint fluid of patients with pain in these groups had lower levels of inflammatory markers. Patients treated with SC had slightly better medium- and long-term therapeutic outcomes than did patients treated with heparin. Patients with poorly controlled hyperuricemia also experienced pain after platelet-rich plasma treatment.

CONCLUSIONS

The results suggest that platelet-rich plasma prepared using high-dose anticoagulants or administered to patients with poorly controlled hyperuricaemia may lead to moderate-to-severe knee pain and joint effusion after joint puncture therapy. Platelet-rich plasma had a therapeutic effect on knee osteoarthritis; however, its efficacy gradually decreased over time. SC anticoagulant is more suitable for platelet-rich plasma preparation than is heparin. Further studies are needed to understand the safety and the various factors influencing platelet-rich plasma therapy.

The use of injectable orthobiologics for knee osteoarthritis: A European ESSKA-ORBIT consensus. Part 1-Blood-derived products (platelet-rich plasma)

PURPOSE

The aim of this European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) consensus is to provide recommendations based on evidence and expert opinion to improve indications, decision-making and administration-related aspects when using blood-derived orthobiologics (for simplicity indicated as PRP-platelet-rich plasma-with PRP being the most common product) for the management of knee osteoarthritis (OA).

METHODS

Leading European expert clinicians and scientists were divided into a steering group, a rating group and a peer review group. The steering group prepared 28 question-statement sets divided into three sections: PRP rationale and indications, PRP preparation and characterisation and PRP protocol. The quality of the statements received grades of recommendation ranging from A (high-level scientific support) to B (scientific presumption), C (low-level scientific support) or D (expert opinion). The question-statement sets were then evaluated by the rating group, and the statements scored from 1 to 9 based on their degree of agreement with the statements produced by the steering group. Once a general consensus was reached between the steering and rating groups, the document was submitted to the peer review group who evaluated the geographic adaptability and approved the document. A final combined meeting of all the members of the consensus was held to produce the official document.

RESULTS

The literature review on the use of blood-derived products for knee OA revealed that 9 of 28 questions/statements had the support of high-level scientific literature, while the other 19 were supported by a medium-low scientific quality. Three of the 28 recommendations were grade A recommendations: (1) There is enough preclinical and clinical evidence to support the use of PRP in knee OA. This recommendation was considered appropriate with a strong agreement (mean: 8). (2) Clinical evidence has shown the effectiveness of PRP in patients for mild to moderate degrees of knee OA (KL ≤ 3). This recommendation was considered appropriate with a strong agreement (mean: 8.1). (3) PRP injections have been shown to provide a longer effect in comparison to the short-term effect of CS injections. They also seem to provide a safer use profile with less potential related complications. This recommendation was considered appropriate with a very strong agreement (mean: 8.7). Six statements were grade B recommendations, 7 were grade C and 12 were grade D. The mean rating score was 8.2 ± 0.3.

CONCLUSIONS

The consensus group reached a high level of agreement on all the questions/statements despite the lack of clear evidence for some questions. According to the results from this consensus group, given the large body of existing literature and expert opinions, PRP was regarded as a valid treatment option for knee OA and as a possible first-line injectable treatment option for nonoperative management of knee OA, mainly for KL grades 1-3.

LEVEL OF EVIDENCE

Level II.

Prognostic Factors in Intra-articular Platelet-Rich Plasma Treatment for Knee Osteoarthritis: A Comparative Analysis of Responders and Nonresponders

BACKGROUND

Knee osteoarthritis (KOA) is a chronic joint disease affecting activities of daily living (ADL) and quality of life due to pain and limited range of motion, afflicting a large number of patients worldwide. However, it is difficult to prevent the progression of the disease. Therapeutic strategies for KOA aim to maintain ADL and QOL by alleviating pain or managing locomotive function. Recently, intra-articular injection of platelet-rich plasma (PRP) has been gaining attention. In this study, the clinical results of PRP treatment in our institution were reported and compared between responders and non-responders using patient characteristics and imaging data assessed from plain X-rays and magnetic resonance imaging (MRI).

METHODS

Participants in the study were KOA patients with varus deformity assessed as grade 2 or higher in the Kellgren-Lawrence classification who received PRP treatment from January 2022 to November 2023 and were followed up for at least three months. PRP was prepared with 27 mL of blood collected from the patient, and 2.7 mL of PRP was prepared using the PEAK©︎PRP System from DePuy Synthes (Raynham, MA). Intra-articular injections of PRP were performed under echo-guided procedures, and responders or non-responders were determined using the Osteoarthritis Research Society International Standing Committee for Clinical Trials Response Criteria Initiative (OMERACT-OARSI) criteria evaluated by the Japanese Knee Injury and Osteoarthritis Outcome Score (J-KOOS) at three months after PRP injection. The clinical efficacy of PRP treatment for KOA was assessed in this study, and a dichotomous analysis was performed comparing the responder group and the non-responder group using patient characteristics and assessed data from plain X-ray images and MRI to determine prognostic factors for PRP treatment.

RESULTS

The study population included 36 knees with a mean age of 70.6. ± 9.2 years, comprising six knees in men and 30 knees in women. The responder group consisted of 16 knees (44.4%), and the non-responder group consisted of 20 knees (55.6%). J-KOOS subscores at pre-treatment elicited that each subscale in the R group was significantly lower than that in the NR group at pretreatment. A dichotomous analysis for the two groups revealed the distribution of sex and past medical history of hyperlipidemia to be significantly different between the two groups. Multivariable logistic regression analysis showed that the coexistence of hyperlipidemia was the main prognostic factor for the efficacy of PRP therapy.

DISCUSSION

In this study, comparisons were conducted between responders and non-responders to estimate prognostic factors for the efficacy of PRP therapy. Surprisingly, responders to the treatment tended to show lower J-KOOS scores and to have hyperlipidemia. A literature review revealed conflicting reports on prognostic factors for PRP therapy in KOA, highlighting the need for further research.

Most Publications Regarding Platelet-Rich Plasma Use in the Knee Are From Asia, Investigate Injection for Osteoarthritis, and Show Outcome Improvement: A Scoping Review

PURPOSE

To evaluate and synthesize the available literature related to platelet-rich plasma (PRP) treatment of knee pathologies and to provide recommendations to inform future research in the field.

METHODS

PubMed, CINAHL, and Scopus databases were queried on October 6, 2023. All identified citations were collated and uploaded into Covidence for screening and data extraction. Studies were included if they were human studies published in English with adult cohorts that received PRP as a procedural injection or surgical augmentation for knee pathologies with patient-reported outcome measures (PROMs) and level of evidence Levels I-IV.

RESULTS

Our search yielded 2,615 studies, of which 155 studies from 2006 to 2023 met the inclusion criteria. Median follow-up was 9 months (±11.2 months). Most studies (75.5%) characterized the leukocyte content of PRP, although most studies (86%) did not use a comprehensive classification scheme. In addition, most studies were from Asia (50%) and Europe (32%) and were from a single center (96%). In terms of treatment, 74% of studies examined PRP as a procedural injection, whereas 26% examined PRP as an augmentation. Most studies (68%) examined treatment of knee osteoarthritis. Many studies (83%) documented significant improvements in PROMs, including 93% of Level III/IV evidence studies and 72% of Level I/II evidence studies, although most studies (70%) failed to include minimal clinically important difference values. The visual analog scale was the most-used PROM (58% of studies), whereas the Short Form Health Survey 36-item was the least-used PROM (5% of studies).

CONCLUSIONS

Most published investigations of knee PRP are performed in Asia, investigate procedural injection for osteoarthritis, and show significant outcome improvements. In addition, this review highlights the need for better classification of PRP formulations.

LEVEL OF EVIDENCE

Level IV, scoping Review of level I-IV studies.

Most Orthopaedic Platelet-Rich Plasma Investigations Don't Report Protocols and Composition: An Updated Systematic Review

PURPOSE

To systematically review the literature to assess the heterogeneity of platelet-rich plasma (PRP) preparation and composition reporting for the treatment of musculoskeletal/orthopaedic pathologies.

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify Level I and Level II studies from 2016 to 2022 that evaluated the use of PRP therapy for musculoskeletal pathologies. The search phrase used was "platelet-rich plasma clinical studies." Studies were assessed based on their reporting of the PRP preparation methods and reporting of PRP composition.

RESULTS

One hundred twenty-four studies (in 120 articles) met inclusion criteria for analysis. Of these studies, 15 (12.1%) provided comprehensive reporting, including a clear, well-described, and reproducible preparation protocol that future investigators can follow. Thirty-three studies (26.6%) quantitatively reported the final PRP product composition.

CONCLUSIONS

Among the studies using PRP for the treatment of musculoskeletal/orthopaedic pathologies, less than 20% provided a clear, well-described, and reproducible PRP preparation protocol, and only one-fourth of studies reported on the final PRP product composition.

CLINICAL RELEVANCE

A diverse current reporting of PRP composition between studies provides a high heterogeneity of the term "PRP," which becomes a limitation for a comparison of studies using PRP.

Three Doses of Platelet-Rich Plasma Therapy Are More Effective Than One Dose of Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Systematic Review and Meta-analysis

PURPOSE

To compare the efficacy of a single dose of platelet-rich plasma (PRP) with multiple doses of PRP therapy in the treatment of knee osteoarthritis (KOA).

METHODS

The PubMed, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Scopus, and Cochrane Library databases were searched from database inception to May 2022; in addition, the gray literature and bibliographic references were searched. Only randomized controlled trials comparing the effect of a single dose versus multiple doses of PRP for KOA were included. Literature retrieval and data extraction were conducted by 3 independent reviewers. The inclusion and exclusion criteria were based on type of study, research subjects, intervention, outcome, language, and availability of data. Pooled analyses of visual analog scale (VAS) scores, Western Ontario and McMaster Universities Arthritis Index scores, and adverse events were conducted.

RESULTS

Seven studies (all randomized controlled trials) of high methodologic quality involving 575 patients were included. The ages of the patients included in this study ranged from 20 to 80 years, and the sex ratio was balanced. Triple-dose PRP therapy resulted in significantly better VAS scores compared with single-dose PRP therapy at 12 months (P < .0001), with no significant change in VAS scores between double-dose PRP and single-dose PRP at 12 months. Regarding adverse events, double-dose (P = .28) and triple-dose (P = .24) therapy showed no significant differences in safety from single-dose therapy.

CONCLUSIONS

Although there is a paucity of large high-quality Level I studies, current best evidence suggests that 3 doses of PRP for KOA are more effective than 1 dose of PRP at providing pain relief up to 1 year after administration.

LEVEL OF EVIDENCE

Level II, systematic review of Level II studies.

Infiltration therapy in the context of cartilage surgery

Guideline-based surgical cartilage therapy for focal cartilage damage offers highly effective possibilities to sustainably reduce patients' complaints and to prevent or at least delay the development of early osteoarthritis. In the knee joint, it has the potential to reduce almost a quarter of the arthroses requiring joint replacement caused by cartilage damage. Biologically effective injection therapies could further improve these results. Based on the currently available literature and preclinical studies, intra- and postoperative injectables may have a positive effect of platelet-rich plasma/fibrin (PRP/PRF) and hyaluronic acid (HA) on cartilage regeneration and, in the case of HA injections, also on the clinical outcome can be assumed. The role of a combination therapy with use of intra-articular corticosteroids is lacking in the absence of adequate study data and cannot be defined yet. With regard to adipose tissue-based cell therapy, the current scientific data do not yet justify any recommendation for its use. Further studies also regarding application intervals, timing and differences in different joints are required.

Substantial Variability in Platelet-Rich Plasma Composition Is Based on Patient Age and Baseline Platelet Count

Purpose

To evaluate the effect of age, sex, body mass index (BMI), and baseline blood count on the final composition of platelet rich-plasma (PRP) and to evaluate the variability of PRP applied in the same patient at 2 different times.

Methods

Potential subjects treated with PRP between January 2019 and December 2021 were identified in an institutional registry. Patient demographics and baseline blood count were prospectively recorded in a consecutive series of patients treated with PRP for a musculoskeletal condition in our Institution. The influence of sex, BMI, age, and baseline blood count on final platelet concentrations in PRP was evaluated. Finally, intrapersonal variability was evaluated.

Results

A total of 403 PRP injections from 357 patients were analyzed from an institutional prospective registry of PRP between January 2019 and December 2021. A directly proportional variation in PRP platelet count of 3.8× was observed for each unit increase in baseline blood platelet count. For every decade increase, we observed an approximate decrease of 32,666 platelets. When the first dose of PRP platelet counts was compared with the second dose of PRP platelet counts between the same patients, significant differences were found. A mean of 890,018 platelets in the first PRP and a mean of 1,244,467 in the second PRP with a mean difference of 354,448 was found (P = .008). We did not find differences in the final concentration of platelets regarding sex, BMI, or PRP protocol.

Conclusions

Overall the final composition of PRP (platelet count) was significantly influenced by patient's age and baseline platelet count. In contrast, BMI, sex and the rest of the components of the baseline blood count did not have a significant influence on final PRP. Furthermore, in patients who received 2 doses of PRP, the final concentration of platelets varied significantly between the 2 preparations.

Level of Evidence

Level IV, prognostic case series.

Multiple Injections of Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Current Evidence in Randomized Controlled Trials

In recent years, various clinical trials have focused on treating knee osteoarthritis (KOA) with multiple injections of platelet-rich plasma (PRP). However, compared with the multiple hyaluronic acid (m-HA) injections, the clinical efficacy of multiple PRP (m-PRP) injections for KOA still remains controversial among these studies. Therefore, we aimed to compare the clinical effectiveness of m-PRP injections with m-HA injections in the treatment of KOA in this systematic review. Relevant clinical trials were searched via bibliographic databases, including Medline, PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials, to compare the m-PRP and m-HA injections in the treatment of KOA. Finally, fourteen randomized controlled trials, including 1512 patients, showed the postoperative VAS, WOMAC, IKDC, or EQ-VAS scores and were enrolled in this systematic review. Compared with the group of intra-articular m-HA injections, the group of intra-articular m-PRP injections was lower in the VAS scores at 3-month (WMD = −0.25; 95%CI, −0.40 to −0.10, p = 0.0009) and 12-month (WMD = −0.64; 95%CI, −0.79 to −0.49, p < 0.00001) follow-ups. In addition, the group of intra-articular m-PRP injections was also lower in the WOMAC scores at 1-month (WMD = −1.23; 95%CI, −2.17 to −0.29, p = 0.01), 3-month (WMD = −5.34; 95%CI, −10.41 to −0.27, p = 0.04), 6-month (WMD = −11.02; 95%CI, −18.09 to −3.95, p = 0.002), and 12-month (WMD = −7.69; 95%CI, −12.86 to −2.52, p = 0.004) follow-ups. Furthermore, compared with the group of intra-articular m-HA injections, the group of intra-articular m-PRP injections was higher in the IKDC scores at 3-month (WMD = 7.45; 95%CI, 2.50 to 12.40, p = 0.003) and 6-month (WMD = 5.06; 95%CI, 1.94 to 8.18, p = 0.001) follow-ups. However, the long-term adverse side of m-PRP injections for KOA still needs more large-scale trials and long-term follow-ups.

Surgical Versus Non-Surgical Treatments for the Knee: Which Is More Effective?

Osteoarthritis is a degenerative joint disease that is extremely prevalent in society. It affects more than 25% of Americans above the age of 18 years. According to July 2020 publication by the Centers for Disease Control (CDC), osteoarthritis affects approximately 325 million Americans. One of the organs that is most affected by osteoarthritis is the knee. Over the years, we have developed non-surgical treatments, such as physical therapy (PT) and injections, and surgical treatments, such as total knee arthroplasty (TKA) and arthroscopic lavage, for knee osteoarthritis (KOA). If a patient fails with non-surgical options, which are tried first to avoid the risks of surgery, the patient may be considered for knee surgery. This article will investigate the different non-surgical options and TKA as treatment options for KOA based on current literature. The goal of this paper is to be a comprehensive resource for physicians and patients with KOA to make an informed decision. A systematic literature search was conducted using PubMed. The search terms were based on the type of treatments for KOA. To find articles that compared TKA to non-surgical treatments, the terms included "osteoarthritis", "total knee", and "non-surgical treatments," in combination. For other non-surgical treatments such as PT, weight reduction, and injections, a combination of the treatment, "osteoarthritis", and "knee" were included in the search. For the tier 1 process, any randomized controlled trials were included. Any case reports, observational studies, and cross-sectional studies were eliminated from the search. For the tier 2 review process, any articles that did not have relevance to the topic were eliminated after reading the abstracts of the articles. After review of the literature, the data seem to suggest that TKA with 12 weeks of non-surgical treatment improved pain and functionality of the knee more than just 12 weeks of non-surgical treatment when followed up at 12 and 24 months. However, non-surgical treatment before TKA delays the need for surgery. Supervised PT, either in a group or individual format, has been shown to delay TKA in 95% patients in the group that received PT at the end of one year. In addition, weight reduction has been shown as an effective strategy to improve pain and functionality in KOA patients, which decreases the urgency for surgery. Furthermore, platelet-rich plasma (PRP) injections have been shown to have long-term symptomatic relief for KOA compared to hyaluronic acid (HA) and corticosteroid injections. However, HA and corticosteroid injections are beneficial in treating KOA more than receiving no treatment. Physicians often have difficulty deciding whether to pursue conservative or surgical treatment for patients with KOA. The non-surgical treatments explored in this review - PT, injections, and weight reduction - can provide symptomatic relief and, in some cases, delay the need for surgical intervention. However, based on some randomized clinical trials mentioned in the article, patients receiving TKA have more relief, better quality of life, and improved functionality compared to non-surgical therapy. However, a critical review of this important field of debate shows that there are limited randomized controlled studies comparing the effectiveness of TKA and non-surgical treatments for KOA. We believe that this controversial topic needs further clinical investigation.

Intra-articular injection of platelet-rich plasma in patients with hemophilia and painful knee joint cartilage degeneration

INTRODUCTION

Knee arthropathy causes pain to people with hemophilia (PWH). One of the current controversies is whether injections of intra-articular platelet-rich plasma (PRP) are effective in relieving the knee pain of PWH.

AREAS COVERED

A narrative literature review was conducted on the efficacy of PRP injections in the knees of PWH.

EXPERT OPINION

Intra-articular PRP knee injections are widely used in patients with knee osteoarthritis to relieve pain and delay total knee arthroplasty. Although numerous publications have supported the use of PRP in knee osteoarthritis, there is still major controversy regarding its true usefulness, given that a number of studies with a high degree of evidence have failed to show the efficacy of PRP. With respect to painful hemophilic arthropathy, the use of PRP injections is even more controversial, as there are only four publications on the subject supporting the use of PRP in hemophilia, all of them with a low degree of evidence. A publication with grade 1 evidence recommended against the use of PRP in hemophilic arthropathy because its efficacy has not been demonstrated. My opinion is that intra-articular PRP injections should not be used in hemophilia until there is more evidence of its benefits.

Biological injection therapy with leukocyte-poor platelet-rich plasma induces cellular alterations, enhancement of lubricin, and inflammatory downregulation in vivo in human knees: A controlled, prospective human clinical trial based on mass spectrometry imaging analysis

Objective

To investigate the in vivo biological effects of leukocyte-poor platelet-rich plasma (LpPRP) treatment in human synovial layer to establish the cellular basis for a prolonged clinical improvement.

Methods

Synovial tissues (n = 367) were prospectively collected from patients undergoing arthroscopic surgery. Autologous-conditioned plasma, LpPRP, was injected into the knees of 163 patients 1-7 days before surgery to reduce operative trauma and inflammation, and to induce the onset of regeneration. A total of 204 patients did not receive any injection. All samples were analyzed by mass spectrometry imaging. Data analysis was evaluated by clustering, classification, and investigation of predictive peptides. Peptide identification was done by tandem mass spectrometry and database matching.

Results

Data analysis revealed two major clusters belonging to LpPRP-treated (LpPRP-1) and untreated (LpPRP-0) patients. Classification analysis showed a discrimination accuracy of 82%-90%. We identified discriminating peptides for CD45 and CD29 receptors (receptor-type tyrosine-protein phosphatase C and integrin beta 1), indicating an enhancement of musculoskeletal stem cells, as well as an enhancement of lubricin, collagen alpha-1-(I) chain, and interleukin-receptor-17-E, dampening the inflammatory reaction in the LpPRP-1 group following LpPRP injection.

Conclusions

We could demonstrate for the first time that injection therapy using "autologic-conditioned biologics" may lead to cellular changes in the synovial membrane that might explain the reported prolonged beneficial clinical effects. Here, we show in vivo cellular changes, possibly based on muscular skeletal stem cell alterations, in the synovial layer. The gliding capacities of joints might be improved by enhancing of lubricin, anti-inflammation by activation of interleukin-17 receptor E, and reduction of the inflammatory process by blocking interleukin-17.

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

INTRODUCTION/OBJECTIVES

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Serial Platelet-Rich Plasma Intra-articular Injections in Kellgren and Lawrence Grade IV Knee Joint Osteoarthritis: A Prospective Blinded Placebo-Controlled Interventional Study

Purpose

The purpose of this study was to evaluate whether serial intra-articular (IA) Platelet-Rich Plasma (PRP) injections improve pain and function in patients of Kellgren-Lawrence (K-L) Grade IV primary knee osteoarthritis (KOA), not willing for arthroplasty or having relative contraindications to surgery.

Methods

90 patients (84 available at final follow-up) of Grade IV KOA were given 3 PRP or Normal Saline injections at 1-month interval. Pain and functional assessment was done with Visual analog scale (VAS) and Western Ontario and McMaster universities osteoarthritis index (WOMAC) respectively, at baseline and then at three and six months of follow-up. Both groups were homogenous with similar baseline characteristics.

Results

Both groups showed statistically significant improvements in the outcome scores but only PRP showed minimal clinically important difference (25% in WOMAC and > 2 cm difference of mean in VAS at follow-up). For inter-group comparison, PRP showed better results as there was statistically significant difference in WOMAC at 3 months (Difference =  - 9.220, 95% CI =  - 13.1945 to - 5.2455, P < 0.0001) and at 6 months (Difference =  - 10.360, 95% CI =  - 14.5358 to - 6.1842, P < 0.0001). Similar results were seen for VAS also (Difference =  - 0.580, 95% CI =  - 1.1412 to - 0.0188, P = 0.04 at 3 months, Difference =  - 0.870, 95% CI - 1.3993 to - 0.3407, P = 0.001 at 6 months). Outcome scores significantly correlated with age and sex but not with body mass index (BMI).

Conclusion

Serial Intra-articular Injections of autologous PRP mildly improve short-term subjective pain and knee function scores in patients of Grade IV KOA without any major complications.

The Current Status of Clinical Trials on Biologics for Cartilage Repair and Osteoarthritis Treatment: An Analysis of ClinicalTrials.gov Data

OBJECTIVE

Biologics are increasingly used for cartilage repair and osteoarthritis (OA) treatment. This study aimed to provide an overview of the clinical trials conducted on this subject.

DESIGN

Two-word combinations of two sets of key words "cartilage"; "joint"; "osteoarthritis" and "biologics"; "stem cells"; "cell implantation" were used to search the database of ClinicalTrials.gov and supplemented with searches of PubMed and EMbase. The registered trials were analyzed for clinical conditions, completion status, phases, and investigated biologics. Recently completed trials with posted/published results were summarized.

RESULTS

From 2000 to 2022, a total of 365 clinical trials were registered at ClinicalTrials.gov to use biologics for cartilage repair and OA treatment. Since 2006, the number of registered trials accelerated at an annual rate of 16.4%. Of the 265 trials designated with a phase, 72% were early Phase 1, Phase 1, and Phase 2. Chondrocytes and platelet-rich plasma (PRP) were studied in nearly equal number of early- and late-stage trials. Mesenchymal stem/stromal cells (MSCs) were the most commonly investigated biologics (38%) and mostly derived from bone marrow and adipose tissue (70%). In last 5 years, 32 of the 72 completed trials posted/published results, among which seven Phase 3 trials investigated chondrocytes, PRP, bone marrow aspirate concentrate, hyaluronic acid, collagen membrane, and albumin.

CONCLUSIONS

There was a rapid increase in the number of registered clinical trials in recent years, using a variety of biologics for cartilage repair and OA treatment. Majority of the biologics still require late-stage trials to validate their clinical effectiveness.

Platelet Rich Plasma Versus Autologous Conditioned Serum in Osteoarthritis of the Knee: Clinical Results of a Five-Year Retrospective Study

Objectives: There is no consensus on the effectiveness of platelet-rich plasma (PRP) and autologous conditioned serum (ACS) in the treatment of knee osteoarthritis (OA). Also, the group of patients who will benefit most from this treatment is not clear. This study aims to understand the effects of two treatment modalities: ACS and PRP on pain and clinical scores in the treatment of OA. For this reason, we compared the long-term (five-year follow up) clinical results of the patients to whom these two treatment methods were applied.

Materials and methods: Eighty-two knee osteoarthritis cases, selected from a database prospectively maintained in our tertiary university hospital after institutional ethics committee approval, examined between January 2013 and September 2020 and treated with ACS and PRP by the same orthobiological treatment team, were retrospectively analyzed. The clinical results of group A (n=40) treated with ACS and group B (n=42) treated with PRP were statistically analyzed. Clinical evaluations were made pre-injection and at one, six, 12, 24 and 60 months post-treatment, using the knee injury and osteoarthritis result score (KOOS) for the evaluation of function and a visual analog scale (VAS) for the evaluation of pain.

Results: Side effects were noted in two patients (5%) in group A and 16 patients (38.1%) in group B. More side effects were seen in group B compared to group A (p<0.001). The better VAS scores in both groups were detected in the sixth and 12th months. When VAS scores were examined, better results were obtained in group A in the 12th and 24th months (p<0.05). When KOOS scores were examined, the superiority of ACS to PRP at 12 and 24 months was shown in KOOS.S, KOOS.P and KOOS.ADL scores (p<0.05). There was no statistically significant difference between the two groups in terms of all scores and baseline scores at 60 months.

Conclusion: The effectiveness of ACS and PRP treatments can last up to two years. After two years, the effectiveness of both treatments decreases. Comparing the two treatments, ACS treatment showed better results on VAS and KOOS scores compared to PRP treatment.

Intra-Articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Review of Their Current Molecular Mechanisms of Action and Their Degree of Efficacy

Knee osteoarthritis (OA) is estimated to affect more than 10% of the population, with a lifetime risk of 45%. Contemporary guidelines advise control of body weight, therapeutic physical exercise, drug treatment (oral non-steroidal anti-inflammatory drugs, paracetamol, opioids), and mechanical aids (walking aids, braces, orthoses). Nevertheless, these treatments typically have only short-term benefits. Intra-articular corticosteroids are typically advised, but only for short-term pain alleviation, given that their benefits last only a few weeks. The efficacy of hyaluronic acid is controversial. When the aforesaid options fail, total knee arthroplasty is generally recommended as an efficacious treatment. However, it is costly and can involve medical and postoperative complications. Therefore, determining alternate safe and effective treatments for knee OA is paramount. Platelet-rich plasma (PRP) has lately been investigated for the treatment of knee OA. This article reviews recent knowledge concerning PRP’s molecular mechanisms of action. The effectiveness of intra-articular PRP injections in the knee joint remains controversial, although most recent publications show pain alleviation in the short term. Orthopedic surgeons treating people with knee OA are becoming increasingly interested in PRP, despite indecisive clinical data and basic science information. Further studies comparing PRP with placebo are required.