Current State of Platelet-Rich Plasma and Cell-Based Therapies for the Treatment of Osteoarthritis and Tendon and Ligament Injuries

Abstract

Orthobiologics encompass numerous substances that are naturally found in the human body including platelet-rich plasma (PRP), isolated growth factors, and cell therapy approaches to theoretically optimize and improve the healing of cartilage, fractures, and injured muscles, tendons, and ligaments.PRP is an autologous derivative of whole blood generated by centrifugation and is perhaps the most widely used orthobiologic treatment modality. Despite a vast amount of literature on its use in osteoarthritis as well as in tendon and ligament pathology, clinical efficacy results remain mixed, partly as a result of insufficient reporting of experimental details or exact compositions of PRP formulations used.Mesenchymal stromal cells (MSCs) can be isolated from a variety of tissues, with the most common being bone marrow aspirate concentrate. Similar to PRP, clinical results in orthopaedics with MSCs have been highly variable, with the quality and concentration of MSCs being highly contingent on the site of procurement and the techniques of harvesting and preparation.Advances in novel orthobiologics, therapeutic targets, and customized orthobiologic therapy will undoubtedly continue to burgeon, with some early promising results from studies targeting fibrosis and senescence.

Clinical Outcome of Multiple Platelet-Rich Plasma Injection and Correlation with PDGF-BB in the Treatment of Knee Osteoarthritis

“…According to prior research, the platelet concentration in PRP necessary for therapeutic administration is 1,000,000 platelets/µL. In the case where the platelet count in whole blood is 200,000 ± 75,000/µL, PRP intended for therapeutic purposes should increase by an average of 400% from its initial value [35][36][37]. Numerous protocols were investigated in order to elevate the concentration of platelets in PRP.…”

“…It is crucial to differentiate between simple and double centrifugation procedures, with the latter requiring a more extensive preparation period but yielding platelet-concentrated plasma. Platelet concentrations sufficient to induce a therapeutic effect are achieved using double centrifugation techniques in all cases [22,23,35].…”

Efficacy of intradiscal injection of platelet-rich plasma in the treatment of discogenic low back pain: A single-arm meta-analysis

“…[30] Platelets contain a large number of growth factors such as platelet-derived growth factor, transforming growth factor-beta, insulin-like growth factor 1, vascular endothelial growth factor, and epithelial growth factor, and when these growth factors are released from platelets, they mediate tissue neogenesis and play an important role in angiogenesis as well as cell proliferation and differentiation. [31][32][33] PRP is now widely used in joint, spinal, skeletal, and muscular disorders; [34][35][36][37][38] however, because there is no standard PRP production procedure, the composition of PRP in clinical studies varies significantly, and differences in composition may affect treatment outcomes. [39] According to the leukocyte and fibrin content, platelet concentrates can be divided into 4 categories: pure PRP (P-PRP), leucocyte-PRP (L-PRP), pure platelet-rich fibrin, and leucocyte-platelet-rich fibrin.…”

Optimizing repair of tendon ruptures and chronic tendinopathies: Integrating the use of biomarkers with biological interventions to improve patient outcomes and clinical trial design

“…While the use of biomarkers to identify those patients who will have a good outcome vs. a less good outcome following an Achilles tendon rupture is very promising, the findings thus far also provide the opportunity to explore their development in other circumstances regarding healing of Achilles tendon injuries, as well as other tendon injuries. As the use of cellular therapies become more established, and hopefully assume clinical validation and regulatory body approval, the combined use of such modalities (139)(140)(141)(142), the combination of biomarker identification and optimized cellular therapies should lead to significant impact on improved healing. Some of these possibilities are discussed briefly below.…”