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

Perspectives for using platelet-rich plasma in the treatment of knee osteoarthritis: Can it be improved through modifications of the protocol?

PURPOSE

Autologous platelet-rich plasma (PRP) injections are widely used in regenerative medicine, including the knee osteoarthritis (OA) therapy. This study reviews methods to enhance PRP therapy for knee OA, aiming to boost articular cartilage recovery.

METHODS

The search was conducted in the eLIBRARY, PubMed (MEDLINE), Ovid, ScienceDirect, and Google Scholar databases extracting publications available by the end of 2023. Studies were included if they simultaneously met the following criteria: (1) effect of using PRP in the recovery of hyaline cartilage damage after OA; (2) at least one way to modify the PRP protocol aimed to increase its efficiency; (3) data on the molecular mechanisms underlying the increase in efficiency of the modified PRP therapy in OA.

RESULTS

The findings of this study highlight the significant role that the composition and modification of PRP protocols play in enhancing chondrogenesis for cartilage repair. Beyond the activation or non-activation of platelets or the inclusion or removal of leukocytes, which are factors that could somehow affect the effectiveness of PRP formulations, the elimination of growth factors such as VEGF and EGF, which negatively influence cartilage regeneration, offers a promising approach to optimize PRP therapy. While growth factors like TGF-β3, PDGF, and IGF have been shown to promote chondrogenesis, the removal of detrimental factors that could contribute to chronic inflammation or OA progression could significantly improve treatment outcomes. Practices such as combining with hyaluronic acid, pre-injection PRP activation, and multiple administrations are clinically common, while other methods like adjusting growth factors concentration are still in development.

CONCLUSION

Various modifications of this technology allow to use molecular mechanisms involved in the restoration of hyaline cartilage and improve the effectiveness of PRP for the treatment of OA. However, significant challenges remain in standardizing PRP preparation and administration protocols. Variability in platelet concentration, growth factor composition, and activation methods complicate the assessment of efficacy and reproducibility.

Effectiveness and safety of intra-articular interventions for knee and hip osteoarthritis based on large randomized trials: A systematic review and network meta-analysis

OBJECTIVE

To quantify the effectiveness and safety of intra-articular interventions for knee and hip osteoarthritis (OA) through a systematic review and Bayesian random-effects network meta-analysis.

DESIGN

We searched CENTRAL and regulatory agency websites (inception-2023) for large, English-language, randomized controlled trials (RCTs) (≥100 patients/group) examining any intra-articular intervention.

PRIMARY OUTCOME

pain intensity.

SECONDARY OUTCOMES

physical function and safety outcomes. Pain and function outcomes were analyzed at 2, 6, 12, 24, and 52 weeks post-randomization, and presented as standardized mean differences (SMDs) (95% credible intervals, 95% CrI). The prespecified minimal clinically important between-group difference (MID) was -0.37 SMD. Safety outcomes were presented as odds ratios (OR) (95% CrI).

FINDINGS

Among 57 RCTs (22,795 participants) examining 18 intra-articular interventions, usual care or placebo, treatment effects were larger in 35 high-risk-of-bias trials than in 22 low/unclear-risk-of-bias trials. In the main analysis (excluding high-risk-of-bias trials), triamcinolone had the highest probabilities of reaching the MID at weeks 2 and 6 (75.3% and 90%, respectively) with corresponding SMDs of -0.48 (95% CrI,-0.85 to -0.10) and -0.53 (95% CrI,-0.79 to -0.27) compared to placebo (1 trial). The complex homeopathic products Tr14/Ze14 showed therapeutic potential at week 6 compared to placebo (SMD:-0.42, 95% CrI,-0.71 to -0.11, 63.5% probability of reaching the MID, 1 trial). Hyaluronic acid had no effect on pain (SMD:-0.04, 95% CrI,-0.19 to 0.11, 11 trials) but a higher risk of dropouts due to adverse events (OR: 2.01, 95% CrI,1.08 to 3.77) and serious adverse events (OR: 1.86, 95% CrI, 1.16 to 3.03) than placebo.

CONCLUSION

Triamcinolone had the highest probabilities to have a treatment effect beyond the MID at weeks 2-6. Large RCTs with lower risk of bias indicate that the effects of 16 intra-articular interventions in knee or hip OA were smaller than the MID, and that most were consistent with placebo effects. Lack of evidence of long-term effectiveness underscores the need for further research beyond 24 weeks.

Advanced Non-Operative Interventions for Anterior Knee Pain

PURPOSE OF REVIEW

This review presents evidence for advanced non-operative interventions, including extracorporeal shockwave therapy (ESWT), prolotherapy, platelet-rich plasma (PRP), adipose tissue-derived cells, bone marrow aspirate concentrate, various additional non-corticosteroid injectates, and needle-based interventions for common causes of anterior knee pain in the adult population. These etiologies include osteoarthritis of the knee, patellofemoral pain syndrome, chondromalacia patella, Hoffa fat pad impingement syndrome, patellar/quadriceps tendinopathy, and prepatellar bursitis. This review discusses patient care options using a case-based understanding of interventions by condition while recognizing strength of evidence.

RECENT FINDINGS

ESWT and PRP are the most robustly studied and have greatest evidence for treating tibiofemoral osteoarthritis and for long-term benefit in treating patellar tendinopathy. PRP may have evidence for treatment of chondromalacia and prolotherapy for management of tibiofemoral arthritis; both have limited evidence. Botulinum neurotoxin type A has strong evidence to support use in treating patellofemoral pain syndrome. There is limited evidence to support the use of viscosupplementation, percutaneous needle tenotomy, and medicinal signaling cell-based therapies beyond platelet-rich plasma for anterior knee pain. There is limited research on the management of quadriceps tendinopathy, prepatellar bursitis, patellofemoral osteoarthritis, and Hoffa's fat pad impingement syndrome. Further research and standardization of protocols are necessary to fully assess these treatments' efficacy. ESWT, cell-based, and needle-based interventions, may serve as effective treatment options for patients with anterior knee pain. Selection of each intervention requires understanding the evidence, level of risk, and appropriate application based on a patient's level of activity to enable clinicians to enhance patient outcomes and quality of life.

The Well-Forgotten Old: Platelet-Rich Plasma in Modern Anti-Aging Therapy

Currently, approaches to personalized medicine are actively developing. For example, the use of platelet-rich plasma (PRP) is actively growing every year. As a result of activation, platelets release a wide range of growth factors, cytokines, chemokines, and angiogenic factors, after which these molecules regulate chemotaxis, inflammation, and vasomotor function and play a crucial role in restoring the integrity of damaged vascular walls, angiogenesis, and tissue regeneration. Due to these characteristics, PRP has a wide potential in regenerative medicine and gerontology. PRP products are actively used not only in esthetic medicine but also to stimulate tissue regeneration and relieve chronic inflammation. PRP therapy has a number of advantages, but the controversial results of clinical studies, a lack of standardization of the sample preparation of the material, and insufficient objective data on the evaluation of efficacy do not allow us to unambiguously look at the use of PRP for therapeutic purposes. In this review, we will examine the current clinical efficacy of PRP-based products and analyze the contribution of PRP in the therapy of diseases associated with aging.

Evidence-based orthobiologic practice: Current evidence review and future directions

The field of orthopedic and regenerative medicine is rapidly evolving with the increasing utilization of orthobiologic. These biologically derived therapies, including platelet-rich plasma, mesenchymal stem cells, bone marrow aspirate concentrate, stromal vascular fraction (SVF), and autologous chondrocyte implantation, are gaining traction for their potential to enhance the body's natural healing processes. They offer a promising alternative to traditional surgical interventions for musculoskeletal injuries and degenerative conditions. Current evidence suggests significant benefits of orthobiologics in treating conditions like osteoarthritis, tendon injuries, and spinal disorders, yet inconsistencies in treatment protocols and outcomes persist. The global market for orthobiologics is projected to grow substantially, driven by advancements in biologic therapies such as adipose-derived stem cells and SVF, and the demand for minimally invasive treatments. Despite their promise, regulatory and ethical challenges, as well as the need for high-quality, standardized research, remain significant obstacles. Future directions in the field include advancements in delivery systems, personalized medicine approaches, and the exploration of novel sources like induced pluripotent stem cells, aiming for more targeted and effective treatments. Collaborative efforts are crucial to overcoming these challenges and ensuring the safe and effective application of orthobiologics in clinical practice.

Mechanisms and applications of the regenerative capacity of platelets-based therapy in knee osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disease in the elderly population and its substantial morbidity and disability impose a heavy economic burden on patients and society. Knee osteoarthritis (KOA) is the most common subtype of OA, which is characterized by damage to progressive articular cartilage, synovitis, and subchondral bone sclerosis. Most current treatments for OA are palliative, primarily aim at symptom management, and do not prevent the progression of the disease or restore degraded cartilage. The activation of α-granules in platelets releases various growth factors that are involved in multiple stages of tissue repair, suggesting potential for disease modification. In recent years, platelet-based therapies, such as platelet-rich plasma, platelet-rich fibrin, and platelet lysates, have emerged as promising regenerative treatments for KOA, but their related effects and mechanisms are still unclear. Therefore, this review aims to summarize the biological characteristics and functions of platelets, classify the products of platelet-based therapy and related preparation methods. Moreover, we summarize the basic research of platelet-based regeneration strategies for KOA and discuss the cellular effects and molecular mechanisms. Further, we describe the general clinical application of platelet-based therapy in the treatment of KOA and the results of the meta-analysis of randomized controlled trials.

Advances with Platelet-Rich Plasma for Bone Healing

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

Advances in Platelet-Rich Plasma Treatment for Spinal Diseases: A Systematic Review

Spinal diseases are commonly associated with pain and neurological symptoms, which negatively impact patients' quality of life. Platelet-rich plasma (PRP) is an autologous source of multiple growth factors and cytokines, with the potential to promote tissue regeneration. Recently, PRP has been widely used for the treatment of musculoskeletal diseases, including spinal diseases, in clinics. Given the increasing popularity of PRP therapy, this article examines the current literature for basic research and emerging clinical applications of this therapy for treating spinal diseases. First, we review in vitro and in vivo studies, evaluating the potential of PRP in repairing intervertebral disc degeneration, promoting bone union in spinal fusion surgeries, and aiding in neurological recovery from spinal cord injury. Second, we address the clinical applications of PRP in treating degenerative spinal disease, including its analgesic effect on low back pain and radicular pain, as well as accelerating bone union during spinal fusion surgery. Basic research demonstrates the promising regenerative potential of PRP, and clinical studies have reported on the safety and efficacy of PRP therapy for treating several spinal diseases. Nevertheless, further high-quality randomized controlled trials would be required to establish clinical evidence of PRP therapy.

Serial intraarticular injections of growth factor concentrate in knee osteoarthritis: A placebo controlled randomized study

Objective

To evaluate and compare clinical efficacy and effect on specific serum biomarker with serial injections of growth factor concentrate (GFC) for knee osteoarthritis (KOA) in a randomized triple blinded placebo controlled interventional study.

Methods

Final assessment was done on 58 patients. Patients with Kellgren-Lawrence grade II, III knee osteoarthritis were administered monthly intraarticular injections(3 injections) of GFC(n = 31) or saline(n = 27) and evaluated clinically with visual analogue scale(VAS) and Western Ontario and McMaster Universities Arthritis Index(WOMAC) at 3,6 and 12 months post therapy. Biochemical analysis was done with serum biomarker of cartilage degeneration, Collagen 2-1 (Coll2-1), estimated at baseline and at final follow up.

Results

Both the groups exhibited statistically significant improvements (P < 0.05) in VAS at 3,6 and 12 months. WOMAC improvement reached statistical significance for GFC group at every evaluation (P < 0.001) but only at 12 months in NS group (P = 0.029). The improvements were clinically meaningful only in GFC group throughout follow up (Minimal clinically important differences >12% of baseline in WOMAC and >2 cm difference in mean for VAS). Intergroup comparison revealed GFC to be much better for both scores at every evaluation (95% CI of 0.2-1.5,[P = 0.008], 1.4-2.9,[P < 0.0001], and 2.7-4.2,[P < 0.0001] for VAS, 7.3-16.0 [P < 0.001], 11.6-21.9 [P < 0.001] and 18.1-31.1[P < 0.001] for WOMAC). Statistically significant decrease in serum Coll2-1 levels were observed for GFC group only. No serious complications were seen.

Conclusion

Serial(three) monthly GFC injections result in clinically meaningful improvement of subjective pain and function outcome scores, sustaining up to 12 months in KOA grade II and III. GFC also lead to significant reduction in serum levels of cartilage degradation biomarker coll2-1.