Luyddy Pires

Pulsed electromagnetic field (PEMF) therapy has attracted interest in knee osteoarthritis (OA) because it can influence cellular signaling and tissue responses through a noninvasive physical stimulus. However, PEMF is not a uniform intervention, and differences in waveform, field strength, applicator geometry, treatment schedule, and biological context complicate comparisons across studies. This narrative review examines the biophysical basis, experimental mechanisms, and clinical evidence for PEMF in knee OA, with attention to rehabilitation and orthobiologic applications. Preclinical studies describe effects involving calcium-dependent signaling, adenosine receptors, inflammatory regulation, metabolic activity, mesenchymal stromal cell paracrine function, and tissue-specific remodeling. Clinical findings are less consistent, since selected PEMF protocols and related pulsed electromagnetic exposures have improved pain, function, or knee extensor strength in individual trials, whereas others showed no added benefit over sham treatment or exercise alone. Human evidence has not established cartilage regeneration or structural disease modification. Translation is further limited by incomplete exposure reporting and substantial heterogeneity between devices. PEMF may therefore be best investigated as an adjuvant therapy directed toward defined biological or clinical targets. Future trials should combine reproducible exposure characterization with appropriate controls, patient selection, and outcomes that distinguish symptom relief, functional adaptation, and structural change.

Hyaluronan-based materials are widely described as hydrogels, yet the term is applied without distinction to preparations that differ fundamentally in structure. This review addresses that imprecision by separating three material states of hyaluronan and by stating the criteria under which each may be called a gel: native linear hyaluronan, which forms a viscoelastic solution; the hexadecylamide derivative (HYADD-4), which self-assembles into a transient physical network through hydrophobic interactions; and hyaluronan cross-linked with 1,4-butanediol diglycidyl ether (BDDE), which forms a covalent three-dimensional network. A material is treated as a gel here only where both a percolated network and a solid-like mechanical response are documented. On that basis the covalent network qualifies; the derivative is elastic-dominated across the walking-to-running frequency band of the knee but has not been subjected to a formal Winter–Chambon analysis and is therefore described as gel-like; and the linear solution does not qualify at the molecular weights and concentrations used in marketed viscosupplements. We review the chemistry of network formation, the comparative physicochemical and rheological behavior, including viscosity, the storage and loss moduli, boundary lubrication, and resistance to enzymatic and oxidative degradation, and the receptor-mediated and anti-inflammatory mechanisms of action involving CD44 and molecular-weight-dependent signaling. Clinical and regenerative applications in osteoarthritis viscosupplementation and in scaffolds and carriers for cells and growth factors are summarized for each state. The networked materials show higher viscoelasticity and greater resistance to degradation than the linear solution, which provides a rationale for longer residence; the evidence for a clinical advantage over conventional hyaluronan, however, rests largely on preclinical and rheological data. A three-state framework is proposed, pending validation, to support clearer interpretation of the literature and more rational material selection.

Chronic musculoskeletal disorders, including osteoarthritis, rheumatoid arthritis, and tendinopathies, converge on persistent synovial inflammation, matrix catabolism, and impaired repair. This review synthesizes molecular evidence that the cholinergic anti-inflammatory pathway (CAP), the efferent vagal arm of the inflammatory reflex, behaves as a rheostat of the musculoskeletal microenvironment. Activation of the α7 nicotinic acetylcholine receptor (α7nAChR) on macrophages, chondrocytes, osteoblasts, and synoviocytes suppresses nuclear factor-κB (NF-κB) and NLRP3 inflammasome signaling, downregulates MMP-1, MMP-3, and MMP-13, and reduces osteoblast RANKL production; effects on OPG and on the RANKL/OPG ratio under vagal stimulation remain uncharacterized, while favoring a pro-resolution M2-like macrophage program; context-dependent pro-inflammatory responses have also been reported. Bidirectional CAP and mesenchymal stromal cell (MSC) crosstalk indicates that MSCs both sense cholinergic cues and require an intact vagal arc for full immunomodulation. Along the gut–vagus–joint axis, dysbiosis and endotoxin translocation attenuate vagal signaling and amplify systemic inflammatory tone. Because orthobiologics such as platelet-rich plasma, bone marrow aspirate concentrate, and MSCs act within this milieu, cholinergic tone appears associated with the terrain that conditions their efficacy. Heart rate variability stratification and vagal neuromodulation may represent testable adjuncts, although prospective validation in orthobiologic populations remains absent. Preclinical and early clinical evidence is critically appraised throughout.

Knee osteoarthritis (KOA) is a degenerative joint condition characterized by progressive cartilage deterioration and chronic pain, leading to functional im

Type 2 diabetes mellitus (T2DM) affects approximately 10–25% of patients undergoing orthopedic procedures and is associated with impaired tissue healing, increased complication rates, and reduced responsiveness to orthobiologic therapies, including platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and mesenchymal stem cell (MSC) preparations. The underlying mechanisms include advanced glycation end-product accumulation, NF-κB-driven chronic inflammation, Nrf2 pathway impairment, mitochondrial dysfunction, and epigenetic diabetic memory, collectively compromising both orthobiologic product quality and the tissue microenvironment. Emerging, predominantly mechanistic evidence suggests that targeted nutritional interventions, including bioactive compounds targeting mitochondrial biogenesis pathways, anti-inflammatory dietary patterns, and specific micronutrients, may modulate these pathological processes and potentially improve orthobiologic outcomes. This narrative review synthesizes evidence from diabetic pathophysiology, orthobiologic outcomes research, and nutritional science to propose a conceptual clinical framework for regenerative medicine optimization in T2DM patients. Critical knowledge gaps are identified, and a research agenda is proposed. The proposed framework, based primarily on mechanistic and preclinical evidence, should be interpreted as a foundation for research prioritization and hypothesis generation rather than as a clinical protocol. Rigorous randomized trials directly evaluating nutritional optimization in orthobiologic therapy for diabetic patients are required before evidence-based recommendations can be established.

To describe and standardize a reproducible posterolateral approach to the posterior iliac crest for bone marrow aspirate (BMA) harvesting, based on a palpa

The efficacy of platelet-rich plasma (PRP) has long been associated with platelet concentration, yet clinical outcomes remain highly variable and frequently inconsistent. This review challenges the assumption that platelet count alone defines PRP efficacy, proposing instead that functional platelet quality and growth-factor bioactivity are equally critical determinants of therapeutic outcomes. Platelets act as carriers of bioactive molecules stored within alpha granules, including growth factors such as platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-β), vascular endothelial growth factor (VEGF), and insulin-like growth factor (IGF), which orchestrate the cellular and molecular events of tissue repair. Variations in donor biology, age, metabolic status, and oxidative stress profoundly influence platelet functionality and growth-factor release. Likewise, centrifugation parameters, temperature control, and activation methods dictate whether these mediators are preserved or prematurely exhausted. Collectively, these findings reveal that platelet number alone cannot predict regenerative potency. The future of PRP standardization requires the integration of platelet quality indices, growth-factor quantification, and patient optimization protocols into clinical practice. By shifting focus from platelet enumeration to bioactivity assessment, regenerative medicine can achieve more consistent, personalized, and scientifically accurate outcomes.

Platelet-rich plasma (PRP) is widely used in regenerative medicine, yet clinical outcomes remain inconsistent. While traditional strategies have focused on platelet concentration and activation methods, emerging evidence suggests that the biological age of platelets, especially platelet senescence, may be a critical but overlooked factor influencing therapeutic efficacy. Senescent platelets display reduced granule content, impaired responsiveness, and heightened pro-inflammatory behavior, all of which can compromise tissue repair and regeneration. This review explores the mechanisms underlying platelet aging, including oxidative stress, mitochondrial dysfunction, and systemic inflammation, and examines how these factors influence PRP performance across diverse clinical contexts. We discuss the functional consequences of platelet senescence, the impact of comorbidities and aging on PRP quality, and current tools to assess platelet functionality, such as HLA-I–based flow cytometry. In addition, we present strategies for pre-procedural optimization, advanced processing techniques, and adjunctive therapies aimed at enhancing platelet quality. Finally, we challenge the prevailing emphasis on high-volume blood collection, highlighting the limitations of quantity-focused protocols and advocating for a shift toward biologically precise, function-driven regenerative interventions. Recognizing and addressing platelet senescence is a key step toward unlocking the full therapeutic potential of PRP-based interventions.

Red blood cells (RBCs) have traditionally been excluded from orthobiologic formulations due to inflammation, oxidative stress, and hemolysis concerns. However, emerging evidence suggests that RBCs may play an active role in regenerative medicine, contributing to immune modulation, vascular support, and oxidative balance. Their interactions with macrophages, involvement in nitric oxide signaling, and release of extracellular vesicles suggest they may influence tissue repair more than previously assumed. Despite these potential benefits, RBC retention in orthobiologic preparations like platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) remains controversial, with most protocols favoring their removal in the absence of robust translational clinical data. This review explores the biological functions of RBCs in regenerative medicine, their potential contributions to PRP and BMAC, and the challenges associated with their inclusion. While concerns about hemolysis and inflammation persist, controlled studies are needed to determine whether selective RBC retention could enhance musculoskeletal healing in some scenarios. Future research should focus on optimizing RBC processing techniques and evaluating their impact on clinical applications. Addressing these gaps will clarify whether RBCs represent an overlooked but valuable component in regenerative therapies or their exclusion remains justified.

At the forefront of regenerative medicine, orthobiologics represent a spectrum of biological substances that offer promising alternatives for tissue repair and regeneration. Traditional surgical treatments often involve significant risks, extended recovery periods, and may not fully restore tissue functionality, creating a strong demand for less invasive options. This paper presents a concise overview of orthobiologics, reexamining their role within the broader landscape of regenerative medicine. Beginning with a brief introduction to orthobiologics, the paper navigates through various types of biological materials and their associated mechanisms of action and clinical applications. By highlighting platelet derivatives, bone marrow-derived products, and processed adipose tissue, among others, it underscores the pivotal role of orthobiologics in prompting biological responses like cellular proliferation, differentiation, and angiogenesis, thereby fostering tissue healing. Furthermore, this paper explores the diverse applications of orthobiologics in orthopedic conditions, outlining their utility in the treatment of bone and soft-tissue injuries. Addressing clinical considerations, it discusses safety profiles, efficacy, patient selection criteria, and emerging challenges. With the limitations of traditional medicine becoming more apparent, orthobiologics offer an innovative and less invasive approach to patient care. Looking forward, this paper approaches future directions in orthobiologics research, emphasizing the need for continued innovation and exploration. Through a concise perspective, this paper aims to provide clinicians, researchers, and stakeholders with a comprehensive understanding of orthobiologics and their evolving role in regenerative medicine.