A Comprehensive Review of Viscosupplementation in Osteoarthritis of the Knee

The effect of a low transition temperature mixture for enhanced bioavailability of celecoxib in combination with hyaluronic acid in a rat model with post-traumatic knee osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis and a leading cause of disability worldwide. Current therapies include pain relief with oral uptake of non-steroidal anti-inflammatory drugs (NSAIDs) and intra-articular injections of hyaluronic acid (HA), to restore the lubricant and protective properties of the joint (viscosupplementation). The administration of both therapies is limited, especially for NSAIDs, given the systemic side-effects. This work intended to explore the potential of a novel injectable gel for osteoarthritis treatment consisting of hyaluronic acid (HA) combined with celecoxib (CEX) incorporated in a glycerol:sorbitol (GS)-based Low Transition Temperature Mixture (LTTM) for enhanced bioavailability. The efficacy of HA+GS+CEX versus HA, HA+CEX and saline control was tested in a post-traumatic osteoarthritis rat model (female Sprague-Dawley rats, n = 6 per group), induced by unilateral anterior cruciate ligament transection and partial medial meniscectomy (ACLt+pMMx). Outcome measures included knee edema, pain-associated behaviour, systemic CEX levels, bone changes as detected by micro-computed tomography, joint degeneration by Mankin score and synovitis by Krenn score. No changes were observed in knee edema between treatments. All HA-containing formulations effectively reduced synovitis, and alleviated pain-associated behaviour. HA+GS+CEX injection limited the peak CEX systemic exposure, prevented the loss of integrity of the subchondral bone plate, and inhibited cartilage degeneration. Overall, although all HA-based formulations reduced pain and inflammation, only the combination of HA+GS+CEX inhibited joint degeneration, suggesting an added therapeutic benefit over HA or HA+CEX alone.

A novel empirical and rheometric assessment of viscoelastic hydrogel implant cohesiveness

Therapeutic implantable hydrogels are increasingly utilized in medicine due to their versatile viscoelastic properties. Nonetheless, the clinical efficacy and longevity of these products is predicated on their ability to retain structural integrity post-implantation. Gel cohesion, defined as the capacity to resist fragmentation, has lacked empirical standardization, especially in high shear environments, with present methods often conflating this mechanical parameter with gel ductility or qualitative perceptions of tackiness. In this study, we introduce a novel quantitative method of cohesion analysis termed the Modulus of Cohesion (MOC). The MOC is derived from rheometric strain sweep testing by calculating the difference between the elastic and viscous moduli from 0% strain to the crossover point. This novel parameter provides a direct measure of mechanical energy storage and dissipation balance, accounting for linear and nonlinear deformation in shear strain. Eleven commercially available hyaluronic acid gels are evaluated using this method, alongside uniaxial tension and drop weight methods to establish correlations between MOC and existing cohesion metrics. Additionally, haptic sensory analysis and aqueous dispersion methods from previous reports are correlated with rheometric and mechanical tests. Our results demonstrate that MOC provides a reliable, reproducible measure of gel cohesiveness, correlating strongly with other quantitative methods with augmented precision.

Molecular Mechanisms and Therapeutic Role of Intra-Articular Hyaluronic Acid in Osteoarthritis: A Precision Medicine Perspective

Background: Osteoarthritis (OA) is a degenerative joint disease characterized by progressive cartilage breakdown, synovial inflammation, and pain, which leads to significant disability. IAHA is widely used because of its viscoelastic properties, which restore synovial fluid homeostasis and reduce symptoms. However, emerging evidence suggests that IAHA exerts additional biological effects including chondroprotection, inflammatory modulation, oxidative stress reduction, and pain modulation, which may influence disease progression. Objective: This narrative review examines the biological mechanisms underlying IAHA's role in OA management. The review explored IAHA's effects on synovial fluid viscoelasticity, inflammatory cytokine modulation, cartilage preservation, oxidative stress regulation, and pain pathways, emphasizing the influence of molecular weight variations on therapeutic efficacy. Additionally, this review evaluates IAHA's integration into multimodal treatment strategies, its potential disease-modifying effects, and future directions for personalized treatment approaches. Methods: A comprehensive literature review was conducted using PubMed, Cochrane Library, EMBASE, Scopus, and Web of Science for studies published between January 2000 and March 2024. The search focused on IAHA's molecular, cellular, and biochemical effects in OA and clinical findings assessing its impact on joint function, pain relief, and disease progression. Results: IAHA improves synovial fluid lubrication, reduces proinflammatory cytokines (IL-1β, TNF-α), inhibits matrix metalloproteinases (MMPs), scavenges reactive oxygen species (ROS), and modulates nociceptive pathways. High-molecular-weight IAHA demonstrates superior efficacy in advanced OA, while low-molecular-weight formulations may be better suited for early-stage disease. Although IAHA's symptom relief is comparable to corticosteroids and NSAIDs, its favorable safety profile and emerging disease-modifying potential support its long-term use in OA management. Conclusions: IAHA represents a multifaceted therapeutic approach bridging symptomatic relief and regenerative strategies. While long-term efficacy, optimal administration protocols, and patient-specific responses remain subjects of ongoing research, refining treatment selection criteria, dosing regimens, and combination strategies may enhance clinical outcomes. Future studies should explore biomarker-driven approaches, standardize treatment protocols, and assess IAHA's synergy with regenerative medicine to optimize its role in OA management.

Intra-Articular Hyaluronic Acid for Knee Osteoarthritis: A Systematic Umbrella Review

Objective: to evaluate the efficacy, safety, and cost-effectiveness of intra-articular hyaluronic acid (IAHA) in treating osteoarthritis (OA), considering innovations in formulations, comparative outcomes, and variability in guidelines. This review aims to synthesize evidence supporting the role of IAHA in multimodal treatment strategies. Materials and Methods: A general, narrative, umbrella review of systematic reviews and meta-analyses was conducted. Clinical practice recommendations and guidelines for IAHA use were also reviewed and evaluated. A comprehensive search was conducted across the main medical data sources. Inclusion criteria focused on studies evaluating the efficacy, safety, and impact of IAHA. Key outcomes included pain reduction (e.g., WOMAC, VAS), functional improvement, safety, and cost-effectiveness. Results: IAHA showed moderate efficacy in pain relief and functional improvement, especially in early-to-moderate OA. The results indicate that hybrid formulations and combination therapies show better clinical outcomes, with expanded efficacy and potential chondroprotection. However, heterogeneity between studies was noted, reflecting variability in patient populations and intervention protocols. International guidelines varied significantly, with some opposing routine use (e.g., AAOS, NICE) and others endorsing IAHA more or less conditionally (e.g., ESCEO, OARSI). Conclusions: IAHA remains a treatment modality in the arsenal of selected populations of people with OA, especially for early and moderate disease. High-quality, standardized studies are still needed to refine IAHA's role and establish personalized guidelines for individual patients. A concerted effort to harmonize global recommendations and economic strategies, such as tiered pricing, can increase equitable access and optimize IAHA's integration of multimodal treatment for OA.

Targeting the NLRP3 inflammasome as a novel therapeutic target for osteoarthritis

Osteoarthritis, the most common arthritic condition, is an age-related progressive disease characterized by the loss of cartilage and synovial inflammation in the knees and hips. Development of pain, stiffness, and considerably restricted mobility of the joints are responsible for the production of matrix metalloproteinases and cytokines. Although several treatments are available for the management of this disease condition, they possess limitations at different levels. Recently, efforts have focused on regulating the production of the NLRP3 inflammasome, which plays a critical role in the disease's progression due to its dysregulation. Inhibition of NLRP3 inflammasome has shown the potential to modulate the production of MMP-13, caspase-1, IL-1β, etc., which has been reflected by positive responses in different preclinical and clinical studies. Aiming inhibition of this NLRP3 inflammasome, several compounds are in different stages of research owing to bring a novel agent for the treatment of osteoarthritis. This review summarizes the mechanistic pathways linking NLRP3 activation to osteoarthritis development and discusses the progress in new therapeutics aimed at effective treatment.

Long-Term Efficacy of Carboxymethyl-Chitosan in Advanced Knee Osteoarthritis: A Twelve-Month Follow-Up Study on Non-Responders to Hyaluronic Acid

Background: Knee osteoarthritis (OA) is a prevalent degenerative joint disease characterized by the degeneration of joint cartilage. Knee OA leads to pain, stiffness, swelling, and decreased mobility, significantly impacting the quality of life of affected people. Advanced-stage osteoarthritis often necessitates surgical intervention due to poor response to conventional treatments, such as intra-articular hyaluronic acid (HA). Carboxymethyl-chitosan (CM-C), an emerging therapeutic agent, has shown potential in reducing inflammation, improving lubrication, and enhancing joint function. This study aimed to evaluate the long-term efficacy of CM-C injections in patients with advanced knee osteoarthritis, non-responders to HA. Methods: This retrospective study included 16 patients (mean age: 79.56 years) with Kellgren-Lawrence grade 3-4 knee OA treated with a single intra-articular injection of CM-C. Pain and functional outcomes were assessed using the Visual Analogue Scale (VAS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) at baseline (T0), one month (T1), three months (T2), six months (T3), and twelve months (T4). Results: Significant pain reduction was observed at early follow up, (VAS: T1 p = 0.0002, T2 p = 0.0265; KOOS Pain: T1 p = 0.0014). However, pain partially returned by T3 and T4. KOOS activities of daily living (p = 0.0005), QoL (p = 0.0396), and Sport and Free Time (p = 0.0367) subscales showed significant improvement at T1, though worsening trends were observed in subsequent follow up with raw values suggesting persistent benefits. Strong negative correlations were found between VAS and KOOS subscales at various follow ups. Conclusions: A single CM-C injection demonstrated early pain relief and functional improvement in advanced knee OA for non-responders to HA. However, the long-term effects may diminish over time, necessitating a careful consideration of re-treatment strategies or combined therapies.

Biomedical applications of functional hydrogels: Innovative developments, relevant clinical trials and advanced products

Functional hydrogels are used for numerous biomedical applications such as tissue engineering, wound dressings, lubricants, contact lenses and advanced drug delivery systems. Most of them are based on synthetic or natural polymers forming a three-dimensional network that contains aqueous media. Among synthetic polymers, poly(meth)acrylates, polyethyleneglycols, poly(vinylalcohols), poly(vinylpyrrolidones), PLGA and poly(urethanes) are of high relevance, whereas natural polymers are mainly polysaccharides such as hyaluronic acid, alginate or chitosan and proteins such as albumin, collagen or elastin. In contrast to most synthetic polymers, natural polymers are biodegradable. Both synthetic and natural polymers are often chemically modified in order to improve or induce favorable properties and functions like high mechanical strength, stiffness, elasticity, high porosity, adhesive properties, in situ gelling properties, high water binding capacity or drug release controlling properties. Within this review we provide an overview about the broad spectrum of biomedical applications of functional hydrogels, summarize innovative approaches, discuss the concept of relevant functional hydrogels that are in clinical trials and highlight advanced products as examples for successful developments.

Electroacupuncture with extensor exercise improves the contraction elastic density of quadriceps in short and long term for knee osteoarthritis

BACKGROUND

Extensor training improves the quadriceps contraction intensity of knee osteoarthritis. But the duration of effects is limited. This study aimed to assess whether electroacupuncture (EA) with extensor training (EA + E) has better short-and long-term effects than simple extensor training (E).

METHODS

Fifty-four patients were categorized into EA + E and E groups. Elastic shear wave imaging was employed to ascertain the quadriceps elastic modulus values (EMV) at different time points and extension angles. WOMAC scale was used to measure knee function.

RESULTS

Compared to before EA, the vastus lateralis (VL) EMV with 180° knee extension immediately after EA increased significantly. After 1 month, the vastus medialis (VM) EMV with 180° extension increased and WOMAC scores decreased significantly than immediately after EA. The EMV of the VM and VL of group EA + E increased, and WOMAC scores decreased significantly compared to group E after 1 month. After 6 months, EMV of the VM and VL in EA + E group significantly increased, and WOMAC scores significantly decreased compared to E group.

CONCLUSIONS

In short- and long-term, EA with extensor training enhances the contraction strength of the quadriceps and knee function for OA.

TRIAL REGISTRATION

This prospective single-center randomized controlled trial was approved by the Review Committee of the First Affiliated Hospital of Sun Yat-sen University (Registration date: 28/02/2023, Ethical Number: [2023] 005; The Clinical trial registration number: ChiCTR2300076651.

KEY POINTS

• The contraction strength of the quadriceps femoris muscle in OA was detected with shear wave elastic ultrasound, and electroacupuncture immediately enhanced the contraction strength. • After the completion of electroacupuncture treatment, the quadriceps strength and the function of knee joint in OA can be continuously improved, which will last for 6 months. • In short and long term, electroacupuncture with extensor training has better enhancement of quadriceps contraction strength of and knee function for OA than extention only.

Enhanced Pain Reduction at Different Stages of Knee Osteoarthritis via Repeated Injections of Hyaluronic Acid with Niacinamide: A Comparative Study

Background: Osteoarthritis (OA) of the knee is the most common joint disease, characterized by the degeneration of joint cartilage. Intra-articular hyaluronic acid (IAHA) injections are a well-established non-surgical treatment. Methods: This retrospective study analyzed knee OA patients receiving IAHA combined with niacinamide injections, assessing pain reduction in relation to patient data, the number of injections, and radiological findings. Results: IAHA injections led to significant pain reduction on the numeric rating scale (NRS) (0-10), with a mean decrease of 3.34 ± 1.65. Pain relief was greater with multiple injections. A comparison of subgroups by injection frequency (1, 2, or >2) showed significant pain reduction between 1 and 2 injections (p = 0.027) and between 1 and >2 injections (p = 0.032). The OA grade measured using the Kellgren-Lawrence (p = 0.95) and Vallotton MRI classifications (p = 0.50) did not correlate with pain reduction. However, patients with meniscal damage (p = 0.02) showed a greater benefit. A strong positive correlation was found between baseline pain intensity and pain reduction (p < 0.001; r = 0.61). Conclusions: IAHA with niacinamide significantly reduces knee OA pain, with more injections enhancing pain relief. Greater benefits were observed in patients with higher baseline pain and meniscal damage. The favorable safety profile and potential for repeated treatments make IAHA a valuable option in knee OA management.

Efficacy and Safety of One Shot of Hyaluronic Acid in Hip Osteoarthritis: Postmarketing Clinical Follow-Up for Real-World Evidence

Purpose

This study aims to evaluate the real-world efficacy and safety of intra-articular (IA) hyaluronic acid (HA) injections in patients with hip osteoarthritis (OA). Given the increasing burden of hip osteoarthritis and limited evidence supporting viscosupplementation in this context, this research aims to provide valuable insights under real clinical practice conditions.

Patients and Methods

An observational, cross-sectional and retrospective study was conducted in a cohort of patients with hip OA treated with a single injection of HA (Adant One, Meiji Pharma Spain, Spain) from January 2021 to December 2022. Data on patient demographics, clinical characteristics, and treatment outcomes were collected. Efficacy regarding pain relief and/or function improvement was assessed at 6 months using the Visual Analogue Scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Data were pseudonymized. The study was approved by the Research Ethics Committee of the Autonomous Community of Aragon (CEICA).

Results

The study included 40 patients with a mean age of 62.8 years, with 72.5% being female. Significant improvement was observed six-months post-treatment: 25% and 18.5% reduction in pain (VAS and WOMAC, respectively), 11.6% improvement in function (WOMAC), 7.4% improvement in stiffness (WOMAC), and 13.6% improvement in total WOMAC. No adverse events were reported.

Conclusion

A single injection of IA HA significantly improved pain and function in patients with hip OA. These findings support the use of viscosupplementation for hip OA management and underscore the need for further studies to confirm these results and assess the long-term benefits of IA HA in hip OA.

Intraarticular gold for knee osteoarthritis: An ancillary analysis of biomarkers and outcome of a pilot study

Objective

In a previous pilot study, we have shown that intraarticular gold micro-particles can reduce knee osteoarthritis (KOA) pain at two years follow-up. Proteomic changes in serum and synovial fluid within eight weeks were associated with multiple inflammatory and immunological processes. The relation between the different biomarkers and the outcome measures is not known. We hypothesized that improvement in pain and function were associated with specific groups of biomarkers. We present the integrative analyses between proteomic biomarkers and outcomes.

Design

A cohort of 30 patients, with moderate KOA, were included. Using the patients' synovial fluid as the carrier, 20 ​mg gold microparticles were injected intraarticularly. Clinical outcome measures at inclusion, 8 weeks, and 2 years, were the PainDetect questionnaire, WOMAC pain, stiffness, and function. In addition, Quantitative Sensory Testing, Pain Pressure Threshold, Temporal Summation, Conditioned Pain Modulation, and pain diary were assessed at inclusion and after 8 weeks. Proteomic analysis was performed on SF and blood samples before and after 8 weeks of treatment.

Results

Linear combinations of serum or synovial biomarkers changed significantly alongside the effect measures and PainDetect scores following gold micro-particle treatment. Of particular interest was identifying multiple members of a molecular complex that is suggestive of neural tissue regeneration and modulation following gold micro-particle treatment.

Conclusions

Gold microparticles are a possible future option for the treatment of knee osteoarthritis. The treatment triggers putative regenerative and inflammation-modulating molecular mechanisms.

Intra-articular injections of ozone versus hyaluronic acid for knee osteoarthritis: a level I meta-analysis

INTRODUCTION

Intra-articular injections of ozone and hyaluronic acid (HA) are routinely performed for the management of knee osteoarthritis. The present meta-analysis compared intra-articular injections of HA versus ozone in patients with knee osteoarthritis (OA) in patient-reported outcome measures (PROMs). The outcomes of interest were to determine if intra-articular ozone injections show comparable visual analogue scale (VAS) and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) scores compared to intra-articular HA injections.

METHODS

This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the 2020 PRISMA statement. In January 2024, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. All the randomised controlled trials (RCTs) comparing intra-articular HA versus ozone injections in patients with knee OA were accessed. Only studies which clearly stated that injections were performed in patients with knee OA were considered. Data concerning the VAS and WOMAC were retrieved at baseline and the last follow-up. Studies with a follow-up shorter than 4 months or longer than 6 months were not included.

RESULTS

Data from 424 patients were collected. 74% (314 of 424 patients) were women. The mean age of the patients was 61.1 ± 4.5 years, and the mean BMI was 27.8 ± 0.8 kg/m2. Compatibility was found in the mean age, mean BMI, PROMs, and the percentage of women. No difference was found in VAS at follow-up (P = 0.4).

CONCLUSION

The current level I evidence suggests that ozone and HA intra-articular injections achieve similar pain control between 4 and 6 months of follow-up.

LEVEL OF EVIDENCE

Level I.

EUROVISCO Consensus Guidelines for the Use of Hyaluronic Acid Viscosupplementation in Knee Osteoarthritis Based on Patient Characteristics

OBJECTIVES

Viscosupplementation with hyaluronic acid (HA) is a commonly used intra-articular treatment for osteoarthritis (OA). We performed a Delphi consensus process to formulate guidelines for the use of intra-articular hyaluronic acid (IAHA) knee injection according to the patient's characteristics.

METHODS

The EUROVISCO group consists of 12 members who had expertise in clinical and/or research in the field of OA and IAHA treatment. This group drafted issues through an iterative process and subsequently voted according to a Delphi process on their level of agreement (LoA) on these recommendations. The scores were pooled to generate a median agreement score for each recommendation. The strength of the recommendation (SOR) was classified as strong if the median agreement score was ≥8. The level of consensus (LOC) was also obtained. The level of evidence was given for each recommendation.

RESULTS

A total of 34 statements were evaluated by the expert group. A unanimous or high LoA was obtained in 16. IAHA can be considered irrespective of the age in patients with symptomatic knee OA. It can be used in patients with diabetes and/or moderate to severe obesity. It can also be used in knee OA patients with a history of gout, meniscocalcinosis and with mild-to-moderate varus/valgus malalignment. The group recommended against the use of VS in pregnant women and in OA flare.

CONCLUSION

In summary, the working group provided strong recommendations for the use of IAHA injection that will facilitate individualized treatment decision algorithms in the management of knee OA.

Targeting inflammation with hyaluronic acid-based micro- and nanotechnology: A disease-oriented review

Inflammation is a pivotal immune response in numerous diseases and presents therapeutic challenges. Traditional anti-inflammatory drugs and emerging cytokine inhibitors encounter obstacles such as limited bioavailability, poor tissue distribution, and adverse effects. Hyaluronic acid (HA), a versatile biopolymer, is widely employed to deliver therapeutic agents, including anti-inflammatory drugs, genes, and cell therapies owing to its unique properties, such as hydrophilicity, biodegradability, and safety. HA interacts with cell receptors to initiate processes such as angiogenesis, cell proliferation, and immune regulation. HA-based drug delivery systems offer dual strategies for effective inflammation management, capitalizing on passive and active mechanisms. This synergy permits the mitigation of inflammation by lowering the doses of anti-inflammatory drugs and their off-target adverse effects. A diverse array of micro- and nanotechnology techniques enable the fabrication of tailored HA-engineered systems, including hydrogels, microgels, nanogels, microneedles, nanofibers, and 3D-printed scaffolds, for diverse formulations and administration routes. This review explores recent insights into HA pharmacology in inflammatory conditions, material design, and fabrication methods, as well as its applications across a spectrum of inflammatory diseases, such as atherosclerosis, psoriasis, dermatitis, wound healing, rheumatoid arthritis, osteoarthritis, inflammatory bowel disease, and colitis, highlighting its potential for clinical translation.

Lubricant Strategies in Osteoarthritis Treatment: Transitioning from Natural Lubricants to Drug Delivery Particles with Lubricant Properties

Osteoarthritis (OA) is a debilitating joint disease characterized by cartilage degradation, leading to pain and functional impairment. A key contributor to OA progression is the decline in cartilage lubrication. In physiological conditions, synovial fluid (SF) macromolecules like hyaluronic acid (HA), phospholipids, and lubricin play a crucial role in the boundary lubrication of articular cartilage. In early OA, cartilage damage triggers inflammation, altering SF composition and compromising the lubrication layer. This increases friction between mating interfaces, worsening cartilage degradation and local inflammation. Therefore, early-stage restoration of lubrication (by injecting in the joint different classes of compounds and formulations) could alleviate, and potentially reverse, OA progression. In the light of this, a broad variety of lubricants have been investigated for their ability to reduce friction in OA joints and promote cartilage repair in clinical and preclinical studies. This review examines recent advancements in lubricant-based therapy for OA, focusing on natural, bioinspired, and alternative products. Starting from the currently applied therapy, mainly based on natural lubricants as HA, we will present their modified versions, either in hydrogel form or with specific biomimetic moieties with the aim of reducing their clearance from the joint and of enhancing their lubricating properties. Finally, the most advanced and recent formulation, represented by alternative strategies, will be proposed. Particular emphasis will be placed on those ones involving new types of hydrogels, microparticles, nanoparticles, and liposomes, which are currently under investigation in preclinical studies. The potential application of particles and liposomes could foster the transition from natural lubricants to Drug Delivery Systems (DDSs) with lubricant features; transition which could provide more complete OA treatments, by simultaneously providing lubrication replacement and sustained release of different payloads and active agents directly at the joint level. Within each category, we will examine relevant preclinical studies, highlighting challenges and future prospects.

Safety and efficacy of an allogeneic adipose-derived mesenchymal stem cell preparation in the treatment of knee osteoarthritis: A Phase I/IIa randomised controlled trial

Objectives

To assess the safety and efficacy of an allogeneic adipose-derived mesenchymal stem cell preparation (MAG200) in the treatment of knee osteoarthritis over 12 months.

Design

A single-centre, double-blind, ascending dose, randomised controlled trial. 40 participants with moderate knee osteoarthritis were randomised to receive a single intra-articular injection of MAG200 (dose cohorts:10, 20, 50, 100 ​× ​106 ​cells) or placebo. Primary objectives were safety and efficacy according to a compound responder analysis of minimal clinically important difference in pain (numerical pain rating scale [NPRS]) and function (Knee Injury and Osteoarthritis Outcome Score - Function in Daily Living subscale [KOOSADL]) at month 12. Secondary efficacy outcomes included changes from baseline in patient reported outcome measures and evaluation of disease-modification using quantitative MRI.

Results

Treatment was well tolerated with no treatment-related serious adverse events. MAG200 cohorts reported a greater proportion of responders than placebo and demonstrated clinical and statistically significant improvement in pain and clinically relevant improvement in all KOOS subscales. MAG200 demonstrated a reproducible treatment effect over placebo, which was clinically relevant for pain in the 10 ​× ​106 dose cohort (mean difference NPRS:-2.25[95%CI:-4.47,-0.03, p ​= ​0.0468]) and for function in the 20 ​× ​106 and 100 ​× ​106 dose cohorts (mean difference KOOSADL:10.12[95%CI:-1.51,21.76, p ​= ​0.0863] and 10.81[95%CI:-1.42,23.04, p ​= ​0.0810] respectively). A trend in disease-modification was observed with improvement in total knee cartilage volume in MAG200 10, 20, and 100 ​× ​106 dose cohorts, with progression of osteoarthritis in placebo, though this was not statistically significant. No clear dose response was observed.

Conclusion

This early-phase study provides supportive safety and efficacy evidence to progress MAG200 to later-stage trial development.

Trial registration

ACTRN12617001095358/ACTRN12621000622808.

A Review of Current Approaches to Pain Management in Knee Osteoarthritis with a Focus on Italian Clinical Landscape

The global cases of knee osteoarthritis (KOA) are projected to increase by 74.9% by 2050. Currently, over half of patients remain dissatisfied with their pain relief. This review addresses unmet needs for moderate-to-severe KOA pain; it offers evidence and insights for improved management. Italian experts from the fields of rheumatology, physical medicine and rehabilitation, orthopedics, primary care, and pain therapy have identified several key issues. They emphasized the need for standardized care protocols to address inconsistencies in patient management across different specialties. Early diagnosis is crucial, as cartilage responds better to early protective and structural therapies. Faster access to physiatrist evaluation and reimbursement for physical, rehabilitative, and pharmacological treatments, including intra-articular (IA) therapy, could reduce access disparities. Concerns surround the adverse effects of oral pharmacological treatments, highlighting the need for safer alternatives. Patient satisfaction with corticosteroids and hyaluronic acid-based IA therapies reduces over time and there is no consensus on the optimal IA therapy protocol. Surgery should be reserved for severe symptoms and radiographic KOA evidence, as chronic pain post-surgery poses significant societal and economic burdens. The experts advocate for a multidisciplinary approach, promoting interaction and collaboration between specialists and general practitioners, to enhance KOA care and treatment consistency in Italy.

Cartilage Integrity: A Review of Mechanical and Frictional Properties and Repair Approaches in Osteoarthritis

Osteoarthritis (OA) is one of the most common causes of disability around the globe, especially in aging populations. The main symptoms of OA are pain and loss of motion and function of the affected joint. Hyaline cartilage has limited ability for regeneration due to its avascularity, lack of nerve endings, and very slow metabolism. Total joint replacement (TJR) has to date been used as the treatment of end-stage disease. Various joint-sparing alternatives, including conservative and surgical treatment, have been proposed in the literature; however, no treatment to date has been fully successful in restoring hyaline cartilage. The mechanical and frictional properties of the cartilage are of paramount importance in terms of cartilage resistance to continuous loading. OA causes numerous changes in the macro- and microstructure of cartilage, affecting its mechanical properties. Increased friction and reduced load-bearing capability of the cartilage accelerate further degradation of tissue by exerting increased loads on the healthy surrounding tissues. Cartilage repair techniques aim to restore function and reduce pain in the affected joint. Numerous studies have investigated the biological aspects of OA progression and cartilage repair techniques. However, the mechanical properties of cartilage repair techniques are of vital importance and must be addressed too. This review, therefore, addresses the mechanical and frictional properties of articular cartilage and its changes during OA, and it summarizes the mechanical outcomes of cartilage repair techniques.

Intra-articular interventions in osteoarthritis: Navigating the landscape of hyaluronic acid, mesenchymal stem cells, and platelet-rich plasma

Osteoarthritis (OA) poses a substantial burden on patients, leading to pain, functional decline, and reduced quality of life. While conventional treatments focus on symptom management, disease-modifying interventions are yet to be established. This review explores the efficacy of intra-articular interventions, particularly hyaluronic acid (HA), mesenchymal stem cells (MSCs), and platelet-rich plasma (PRP), in the context of OA management. HA injections, with diverse formulations like Hylan G-F20, sodium hyaluronate, and hyaluronan, present varying outcomes, necessitating a nuanced understanding of their effectiveness and timing. MSC therapy, derived from adipose tissue, umbilical cord, or bone marrow, shows promising results in clinical improvement, with adipose-derived MSCs demonstrating efficacy in maintaining benefits over 6 mo. Conversely, bone-marrow-derived MSCs show limited effectiveness, highlighting the need for source-specific considerations. PRP has emerged as a superior option for long-term pain reduction and quality of life improvement, with leukocyte-poor formulations and a critical platelet count of 10 billion demonstrating optimal results. This comprehensive analysis underscores the potential of intra-articular interventions in OA management, emphasizing the need for personalized and evidence-based approaches to enhance treatment efficacy and patient outcomes.

Bottlebrush Polymers for Articular Joint Lubrication: Influence of Anchoring Group Chemistry on Lubrication Properties

The role of carboxylic, aldehyde, or epoxide groups incorporated into bottlebrush macromolecules as anchoring blocks (or cartilage-binding blocks) is investigated by measuring their lubricating properties and cartilage-binding effectiveness. Mica modified with amine groups is used to mimic the cartilage surface, while bottlebrush polymers functionalized with carboxylic, aldehyde, or epoxide groups played the role of the lubricant interacting with the cartilage surface. We demonstrate that bottlebrushes with anchoring blocks effectively reduce the friction coefficient on modified surfaces by 75-95% compared to unmodified mica. The most efficient polymer appears to be the one with epoxide groups, which can react spontaneously with amines at room temperature. In this case, the value of the friction coefficient is the lowest and equals 0.009 ± 0.001, representing a 95% reduction compared to measurements on nonmodified mica. These results show that the presence of the functional groups within the anchoring blocks has a significant influence on interactions between the bottlebrush polymer and cartilage surface. All synthesized bottlebrush polymers are also used in the preliminary lubrication tests carried out on animal cartilage surfaces. The developed materials are very promising for future in vivo studies to be used in osteoarthritis treatment.

A Meta-Analytical Way of Systematizing the Use of Hyaluronan Gels for the Relief of Osteoarthritis, Compared with New Treatment Alternatives

Hyaluronic acid, in the form of a gel or viscoelastic colloidal solution, is currently used for the viscosupplementation of joints affected by osteoarthritis, but its effectiveness is under debate in relation to newer alternatives. Based on meta-analytical arguments, the present article reinforces the opinion that there are still no decisive arguments for its complete replacement but for its use adapted to the peculiarities of the disease manifestation and of the patients. A "broad" comparison is first made with almost all alternatives studied in the last decade, and then a meta-regression study is performed to compare and predict the effect size induced by viscosupplementation therapy and its main challenger of clinical interest, the platelet-rich plasma treatment. If they are computerized, the developed models can represent tools for clinicians in determining the appropriateness of the option or not for viscosupplementation in a manner adapted to the pain felt by the patients, to their age, or to other clinical circumstances. The models were generated using algorithms implemented in the R language and assembled in different R packages. All primary data and necessary R scripts are provided in accordance with the philosophy of reproducible research. Finally, we adhere in a documented way to the opinion that HA-based products, currently under circumspection, are still clinically useful.

Can Hyaluronic Acid Combined with Chondroitin Sulfate in Viscosupplementation of Knee Osteoarthritis Improve Pain Symptoms and Mobility?

The objective of the present study was to assess the effect of intra-articular Hyaluronic acid (HA) and Chondroitin sulfate (CS) supplementation (Hialurom® Hondro (HH)) on pain symptoms and joint mobility. In total, 60 mg/mL sodium hyaluronate and 90 mg/mL CS were administered to 21 patients (17 females and 4 males) respecting the in-force requirements, excluding patients with some specific comorbidities. In addition to the clinical study (where the pain intensity (severity) and joint mobility were assessed), rheological characterization was conducted evaluating the following parameters: elastic modulus (G'), loss modulus (G″) oscillatory frequency (fc) at 0.5 Hz and 2.5 Hz, crossover frequency (fc), relaxation time (λ) where it was noticed that the addition of chondroitin sulfate (CS) to sodium hyaluronate (SH) significantly enhances and improves the viscoelastic properties, particularly at higher shear frequencies. A significant decrease in pain intensity felt by the subjects was found, from 7.48 (according to Wong-Baker scale)-pain close to 8 (the patient is unable to perform most activities), to more reduced values of 5.86-at 6 weeks after injection, 4.81-at 3 months after injection, and 5.24-at 6 months after injection, improvements in symptoms was fast and durable. Data related to the evolution of joint mobility show that at 6 weeks after injection, the mobility of joints increased by 17.8% and at 6 months by 35.61%. No serious adverse events were reported with undesired effects so that they would impose additional measures. Better resistance to enzymatic degradation and free radicals could be expected from the synergic combination of sodium hyaluronate and chondroitin sodium sulfate, this having a special importance for the patients, granting them the ability to perform more ample movements and reducing dependency on attendants, thus increasing quality of life.

The bioengineering application of hyaluronic acid in tissue regeneration and repair

The multifaceted role of hyaluronic acid (HA) across diverse biomedical disciplines underscores its versatility in tissue regeneration and repair. HA hydrogels employ different crosslinking including chemical (chitosan, collagen), photo- initiation (riboflavin, LAP), enzymatic (HRP/H2O2), and physical interactions (hydrogen bonds, metal coordination). In biophysics and biochemistry, HA's signaling pathways, primarily through CD44 and RHAMM receptors, modulate cell behavior (cell migration; internalization of HA), inflammation, and wound healing. Particularly, smaller HA fragments stimulate inflammatory responses through toll-like receptors, impacting macrophages and cytokine expression. HA's implications in oncology highlight its involvement in tumor progression, metastasis, and treatment. Elevated HA in tumor stroma impacts apoptosis resistance and promotes tumor growth, presenting potential therapeutic targets to halt tumor progression. In orthopedics, HA's presence in synovial fluid aids in osteoarthritis management, as its supplementation alleviates pain, enhances synovial fluid's viscoelastic properties, and promotes cartilage integrity. In ophthalmology, HA's application in dry eye syndrome addresses symptoms by moisturizing the eyes, replenishing tear film deficiencies, and facilitating wound healing. Intravitreal injections and hydrogel-based systems offer versatile approaches for drug delivery and vitreous humor replacement. For skin regeneration and wound healing, HA hydrogel dressings exhibit exceptional properties by promoting moist wound healing and facilitating tissue repair. Integration of advanced regenerative tools like stem cells and solubilized amnion membranes into HA-based systems accelerates wound closure and tissue recovery. Overall, HA's unique properties and interactions render it a promising candidate across diverse biomedical domains, showcasing immense potentials in tissue regeneration and therapeutic interventions. Nevertheless, many detailed cellular and molecular mechanisms of HA and its applications remain unexplored and warrant further investigation.

Demonstrating antibiotic stewardship while diagnosing and treating bilateral pseudoseptic arthritis: a case report

INTRODUCTION

Although viscosupplementation is a commonly used treatment for osteoarthritis and is widely regarded as a safe treatment option, it is associated with the rare complication of pseudoseptic arthritis. Most existing case reports that cite this rare complication employed the use of early broad-spectrum antibiotics.

CASE PRESENTATION

In this case report, we present a 61-year-old African American female patient who presented with bilateral knee pseudoseptic arthritis in the setting of viscosupplementation. She presented 3 days after bilateral viscosupplementation injections with bilateral knee swelling, discomfort, and pain with micromotion. Her white blood cell count (WBC) was 12.83 (4.5-11 normal), her C-reactive protein (CRP) level was 159 mg/L (0-10 normal), and her erythrocyte sedimentation rate (ESR) was 79 mm/hour (0-40 normal). Her left knee aspirate yielded 38,580 WBC with a negative gram stain and negative cultures. Her right knee aspirate yielded 29,670 WBC with a negative gram stain and negative cultures. Through the utilization of careful clinical monitoring, ice therapy, and non-steroidal inflammatory medication, we were able to successfully treat this patient while maintaining proper antibiotic stewardship.

CONCLUSION

Pseudoseptic arthritis in the setting of viscosupplementation can be adequately treated and monitored without the use of antibiotics.

Naked mole-rat hyaluronan

Naked mole rats (NMRs) are renowned for their exceptional longevity and remarkable maintenance of health throughout their lifetime. Their subterranean lifestyle has led to adaptations that have resulted in elevated levels of a very high molecular weight hyaluronan in their tissues. Hyaluronan, a glycosaminoglycan, is a key component of the extracellular matrix, which plays a critical role in maintaining tissue structure and regulating cell signaling pathways. This phenomenon in NMRs is attributed to a higher processing and production capacity by some of their hyaluronan synthases, along with lower degradation by certain hyaluronidases. Furthermore, this adaptation indirectly confers several advantages to NMRs, such as the preservation of skin elasticity and youthful appearance, accelerated wound healing, protection against oxidative stress, and resistance to conditions such as cancer and arthritis, largely attributable to CD44 signaling and other intricate mechanisms. Thus, the main objective of this study was to conduct a comprehensive study of the distinctive features of NMR hyaluronan, particularly emphasizing the currently known molecular mechanisms that contribute to its beneficial properties. Furthermore, this research delves into the potential applications of NMR hyaluronan in both cosmetic and therapeutic fields, as well as the challenges involved.

Three once-weekly intra-articular injections of Hylan G-F 20 significantly improve pain relief compared with placebo in patients with chronic idiopathic knee osteoarthritis: a single-centre, evaluator-blinded and patient-blinded, randomized controlled trial

Background

Clinical trials on the use of viscosupplementation with hyaluronic acid (HA) in patients with knee osteoarthritis (KOA) are inconsistent, making it challenging to determine its value in clinical practice. One issue is the availability of various HA products on the market; differences in their chemical features can impact patient outcomes. Herein, we assess the efficacy and safety of three once-weekly intra-articular (IA) injections of Hylan G-F 20, a high-molecular-weight and highly crosslinked HA product, in patients with KOA. We hypothesized that Hylan G-F 20 would provide significant pain relief with no increased safety risk compared with IA saline (placebo).

Methods

This was a 26-week, patient-blinded and evaluator-blinded, single-centre, randomized placebo- controlled trial. Men or women ≥18 years of age with Larsen grade II or III KOA were included. Patients received IA injections of either Hylan G-F 20 or placebo once a week for 3 weeks. The primary endpoints were the week 12 and 26 visits. Primary efficacy outcomes included visual analogue scale (VAS) pain scores, patient activity level and an overall assessment of clinical condition. Secondary outcomes included adverse events (AEs) that emerged during treatment. The primary analysis included the intention-to-treat population. An alpha level of 0.05 was used in the statistical analysis.

Results

Thirty patients were included in the intention-to-treat population (15 per group). All efficacy outcomes were statistically significant in favour of Hylan G-F 20, except night pain and inactivity stiffness, for both patient- assessed (all p=0.0001 at week 12) and evaluator-assessed (all p=0.0001 at week 12 and p=0.0004-0.0180 at week 26) measurements. There was also a greater proportion of symptom-free patients and those with a >50% improvement in their VAS scores, except night pain, in the Hylan G-F 20 group (p=0.001-0.003 in patient-assessed scores and p<0.0001 to 0.002 in evaluator-assessed scores at week 12). Two patients, one in each group, experienced an AE; no sequelae occurred, and no special treatment was required for either AE. No patients withdrew from the study prematurely due to an AE.

Conclusion

In patients with chronic idiopathic KOA, Hylan G-F 20 provides significant improvements in pain relief compared with placebo with no added safety concerns.

Wharton's jelly and osteoarthritis of the knee

INTRODUCTION

The existing treatment modalities for knee osteoarthritis (OA) do not actually address the pathology. Biological therapies, including those using material derived from perinatal tissues, represent a ground-breaking approach to alleviating the symptoms of OA of the knee.

SOURCE OF DATA

Current scientific literature published in PubMed (MEDLINE), Embase and Scopus databases. Trials registered in various clinical trial databases.

AREAS OF AGREEMENT

Perinatal tissues including Wharton's jelly (WJ) and associated mesenchymal stem cells (MSCs) can be used for the management of knee OA.

AREAS OF CONTROVERSY

The efficacy of WJ and associated MSCs in the management of knee OA is still controversial.

GROWING POINTS

The use of WJ and associated MSCs in the management of knee OA is safe and appears to be effective.

AREAS TIMELY FOR DEVELOPING RESEARCH

The present published evidence suggests that WJ tissue and associated MSCs offer an encouraging alternative for the management of knee OA. The published in vitro, preclinical and clinical investigations demonstrate the therapeutic potential of WJ and promote further research in this field to provide symptomatic relief to patients suffering from OA, aiming also to regenerate the osteoarthritic hyaline cartilage, with disease-modifying effects. Future adequately powered randomized controlled trials should be undertaken to establish whether WJ is helpful in the management of OA of the knee.

Can Combining Hyaluronic Acid and Physiotherapy in Knee Osteoarthritis Improve the Physicochemical Properties of Synovial Fluid?

Known as the degenerative disease of the knee with the highest prevalence, knee osteoarthritis (KOA) is characterized by a gradual destructive mechanism that, in severe cases, can provoke the need for total knee substitution. As the disease progresses, various enzymatic, immunological, and inflammatory processes abnormally degrade hyaluronic acid (HA), SF's main component, and affect the concentrations of specific proteins, with the final results seriously endangering synovial fluid (SF)'s rheological and tribological features and characteristics. No effective treatments have been found to stop the progression of KOA, but the injection of HA-based viscoelastic gels has been considered (alone or combined with physiotherapy (PT)) as an alternative to symptomatic therapies. In order to evaluate the effect of viscosupplementation and PT on the characteristics of SF, SF aspirated from groups treated for KOA (HA Kombihylan® and groups that received Kombihylan® and complex PT) was analyzed and compared from analytical, spectrophotometrical, and rheological perspectives. In the patients treated with PT, the SF extracted 6 weeks after viscosupplementation had a superior elastic modulus (G') and viscous moduli (G″), as well as a homogeneous distribution of proteins and polysaccharides. The viscosupplementation fluid improved the bioadhesive properties of the SF, and the use of the viscosupplementation fluid in conjunction with PT was found to be favorable for the distribution of macromolecules and phospholipids, contributing to the lubrication process and the treatment of OA-affected joints.

Hyaluronan: Sources, Structure, Features and Applications

Hyaluronan (HA) is a non-sulfated glycosaminoglycan that is present in a variety of body tissues and organs. Hyaluronan has a wide range of biological activities that are frequently influenced by molar mass; however, they also depend greatly on the source, purity, and kind of impurities in hyaluronan. High-molar-mass HA has anti-inflammatory, immunosuppressive, and antiangiogenic properties, while low-molar-mass HA has opposite properties. A number of chemical modifications have been performed to enhance the stability of HA and its applications in medical practice. Hyaluronan is widely applied in medicine, such as viscosupplementation, ophthalmology, otolaryngology, wound healing, cosmetics, and drug delivery. In this review, we summarized several medical applications of polymers based on the hyaluronan backbone.

Different doses of hyaluronic acid injections in patients with knee osteoarthritis: A multicenter, randomized, prospective, single-blind, clinical study

BACKGROUND

Many formulations and dosing regimens are available for hyaluronic acid (HA).

OBJECTIVE

To compare different doses of linear, high-molecular weight (HMW) HA injections among patients with knee osteoarthritis (OA).

METHODS

Hundred patients were included in this randomized, single-blinded trial and randomly divided into three HA injection groups. The first group received five weekly 20 mg HA injections, the second group received three weekly 32 mg HA injections, and the third group received a single 48 mg HA injection. Patients were evaluated at baseline, 1, 3, and 6 months after the last injection for pain, stiffness, and function using the visual analog scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire. Quality of life, patient's global assessment, and Timed Up and Go (TUG) test scores were also evaluated.

RESULTS

There was significant improvement in the WOMAC, VAS-pain, quality of life, patient's global assessment, and TUG test mean scores at all follow-up time points (p< 0.001). However, the groups showed no significant differences in WOMAC, VAS-activity pain, and patient global scores at any follow-up point.

CONCLUSION

Intra-articular injections of different doses of linear HMW HA can improve pain, stiffness, function, and quality of life in patients suffering from knee OA over a six-month period.

Effectiveness of gonarthrosis treatment via intra-articular injections of linear vs. cross-linked hyaluronic acids

OBJECTIVES

The study aimed to compare the outcomes of single-dose cross-linked hyaluronic acid and the linear regimen of three doses of HA knee injections among patients with gonarthrosis.

PATIENTS AND METHODS

This single-center, retrospective study was conducted with 60 patients (47 females, 13 males; mean age: 57.9±4.29 years; range, 50 to 65 years) with Kellgren-Lawrence Grade 2 or 3 gonarthrosis between February 2020 and February 2022. Patients were either subjected to intra-articular cross-linked hyaluronic acid (n=30) or linear hyaluronic acid (n=30) injection treatments. Comprehensive assessments of the patients were conducted prior to the injections, as well as at three and six months after injection. The two injection groups were compared regarding the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Oxford Knee Score.

RESULTS

Both injections showed a statistically significant improvement from baseline in both WOMAC and Oxford Knee Score at three and six months (p<0.001). There was no notable distinction in the alteration of WOMAC knee scores between the two injection types. However, a notable discrepancy was observed in the elevation of Oxford Knee Score among patients who received cross-linked knee injections compared to those who underwent linear hyaluronic acid knee injections, signifying a significant increase in the former group (p<0.001).

CONCLUSION

The advantage of a single-dose administration of cross-linked HA knee injections, as opposed to the three-dose regimen required for linear hyaluronic acid, translates into reduced time and cost for the injection process. Moreover, this approach minimizes injection-associated discomfort for patients due to the singular dose administration.

The Application of Fluorescence Anisotropy for Viscosity Measurements of Small Volume Biological Analytes

Time-resolved fluorescence anisotropy has been extensively used to detect changes in bimolecular rotation associated with viscosity levels within cells and other solutions. Physiological alterations of the viscosity of biological fluids have been associated with numerous pathological causes. This current work serves as proof of concept for a method to measure viscosity changes in small analyte volumes representative of biological fluids. The fluorophores used in this study were fluorescein disodium salt and Enhanced Green Fluorescent Protein (EGFP). To assess the ability of the method to accurately detect viscosity values in small volume samples, we conducted measurements with 12 μL and 100 μL samples. No statistically significant changes in determined viscosities were recorded as a function of sample volume for either fluorescent probe. The anisotropy of both fluorescence probes was measured in low viscosity standards ranging from 1.02 to 1.31 cP, representative of physiological fluid values, and showed increasing rotational correlation times in response to increasing viscosity. We also showed that smaller fluid volumes can be diluted to accommodate available cuvette volume requirements without a loss in the accuracy of detecting discrete viscosity variations. Moreover, the ability of this technique to detect subtle viscosity changes in complex fluids similar to physiological ones was assessed by using fetal bovine serum (FBS) containing samples. The presence of FBS in the analytes did not alter the viscosity specific rotational correlation time of EGFP, indicating that this probe does not interact with the tested analyte components and is able to accurately reflect sample viscosity. We also showed that freeze-thaw cycles, reflective of the temperature-dependent processes that biological samples of interest could undergo from the time of collection to analyses, did not impact the viscosity measurements' accuracy. Overall, our data highlight the feasibility of using time-resolved fluorescence anisotropy for precise viscosity measurements in biological samples. This finding is relevant as it could potentially expand the use of this technique for in vitro diagnostic systems.

Impact of hyaluronic acid injection on the knee joint friction

PURPOSE

The purpose of this in vitro study was to investigate whether or not hyaluronic acid supplementation improves knee joint friction during osteoarthritis progression under gait-like loading conditions.

METHODS

Twelve human cadaveric knee joints were equally divided into mild and moderate osteoarthritic groups. After initial conservative preparation, a passive pendulum setup was used to test the whole joints under gait-like conditions before and after hyaluronic acid supplementation. The friction-related damping properties given by the coefficient of friction µ and the damping coefficient c (in kg m2/s) were calculated from the decaying flexion-extension motion of the knee. Subsequently, tibial and femoral cartilage and meniscus samples were extracted from the joints and tested in an established dynamic pin-on-plate tribometer using synthetic synovial fluid followed by synthetic synovial fluid supplemented with hyaluronic acid as lubricant. Friction was quantified by calculating the coefficient of friction.

RESULTS

In the pendulum tests, the moderate OA group indicated significantly lower c0 values (p < 0.05) under stance phase conditions and significantly lower µ0 (p = 0.01) values under swing phase conditions. No degeneration-related statistical differences were found for µend or cend. Friction was not significantly different (p > 0.05) with regard to mild and moderate osteoarthritis in the pin-on-plate tests. Additionally, hyaluronic acid did not affect friction in both, the pendulum (p > 0.05) and pin-on-plate friction tests (p > 0.05).

CONCLUSION

The results of this in vitro study suggested that the friction of cadaveric knee joint tissues does not increase with progressing degeneration. Moreover, hyaluronic acid viscosupplementation does not lead to an initial decrease in knee joint friction.

Efficacy and safety of corticosteroids, hyaluronic acid, and PRP and combination therapy for knee osteoarthritis: a systematic review and network meta-analysis

OBJECTIVE

There are many injectable treatments for knee osteoarthritis with different characteristics and effects, the aim is to understand which one can lead to better and safer results.

METHODS

The PRISMA principles were followed when doing the literature search. Web of Science databases, Embase, the Cochrane Library, PubMed, and the Wanfang database were searched to identified randomized controlled trials that assessed the efficacy of corticosteroids (CSC), platelet-rich plasma (PRP), hyaluronic acid (HA), and combination therapy in treating KOA. Risk of bias was assessed using the relevant Cochrane tools (version 1.0). The outcome measure included the visual analog scale (VAS) score, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score, and treatment-related adverse events. The network meta-analysis was performed using STATA17 software and a Bayesian stratified random effects model.

RESULTS

Network meta-analysis using the Bayesian random-effects model revealed 35 studies with 3104 participants. PRP showed the best WOMAC score at a 3-month follow-up, followed by PRP + HA, HA, placebo, and CSC; PRP + HA scored the highest VAS, followed by PRP, CSC, HA, and placebo. PRP, CSC, HA, and placebo had the highest WOMAC scores six months following treatment; PRP + HA showed the best VAS scores. PRP showed the best WOMAC score at 12 months, followed by PRP + HA, HA, placebo, and CSC; The best VAS score was obtained with PRP, followed by PRP + HA, HA, and CSC. No therapy demonstrated a rise in adverse events linked to the treatment in terms of safety.

CONCLUSIONS

The current study found that PRP and PRP + HA were the most successful in improving function and alleviating pain after 3, 6, and 12 months of follow-up. CSC, HA, PRP, and combination therapy did not result in an increase in the incidence of treatment-related side events as compared to placebo.

Efficacy and safety of TRPV1-related preparations in the treatment of inflammatory arthralgia

BACKGROUND

Currently, medications for the treatment of inflammatory arthralgia are limited. The role and safety of transient receptor potential vanilloid subtype 1 (TRPV1)-related preparations in reducing inflammatory arthralgia have not yet been fully established. Thus, we aimed to review the efficacy and safety of TRPV1-related preparations for the treatment of inflammatory arthralgia.

METHODS

We searched PubMed, Web of Science, Cochrane, and Embase databases for relevant studies, and the primary outcome was pain score (VAS, PI, NRS, and WOMAC).

RESULTS

Six randomized controlled trials involving 481 patients were analyzed. Patients with inflammatory arthralgia who received TRPV1-related preparations had lower pain scores after treatment than those who received placebo or nonsteroidal anti-inflammatory agents (standardized mean difference = -0.525; 95% confidence interval [CI], -0.789 to -0.261; P < .001). There was no significant difference in the incidence of total adverse reactions between the TRPV1-related preparations and control groups (relative risk = 1.225; 95% CI, 0.685 to 2.191; P = .494).

CONCLUSION

TRPV1-related preparations are clinically safe and effective in the treatment of inflammatory arthralgia and are superior to placebo or nonsteroidal drugs. This may be the preferred treatment for patients with inflammatory arthralgia.

Multidisciplinary Rehabilitation after Hyaluronic Acid Injections for Elderly with Knee, Hip, Shoulder, and Temporomandibular Joint Osteoarthritis

Osteoarthritis (OA) is a prevalent degenerative joint condition characterized by cartilage deterioration, joint inflammation, and functional limitations, particularly impacting the elderly population. Rehabilitation and hyaluronic acid (HA) injections are common therapeutic approaches routinely used in clinical practice, but their synergistic potential is far from being fully characterized. Thus, the aim of this narrative review was to elucidate the multilevel benefits and synergies of integrating these two approaches in multidisciplinary OA rehabilitation. This narrative review follows the scale for the assessment of narrative review articles (SANRA) criteria and involves a comprehensive literature search from July to August 2023. Two independent reviewers screened studies, including those involving human subjects with OA, rehabilitation strategies, and outcomes following HA injection, published in English. Results: HA injections might improve joint biomechanics, reducing friction, absorbing shocks, and potentially regulating inflammation. Rehabilitation plays a pivotal role in strengthening muscles, increasing the range of motion, and enhancing overall function. Optimizing rehabilitation following HA injection might provide additional benefits in joint health. OA management requires a multidisciplinary approach integrating HA injections, rehabilitation, and personalized care. Challenges in patient adherence and healthcare resources currently exist, but emerging technologies offer opportunities to enhance patient engagement and monitoring optimizing sustainability and outcomes of patients with knee, hip, shoulder, and temporomandibular joint OA.

Boron Nitride's Morphological Role in the Design of Injectable Hyaluronic Acid Based Hybrid Artificial Synovial Fluid

The treatment process of osteoarthritis (OA) is challenging as it affects not only cartilage but also subchondral bone, ligament attachment capsules, synovium, and surrounding muscle tissue. Therefore, the search for preventive treatment or methods to slow the onset of the condition. Hexagonal boron nitride (hBN) has a graphite-like lamellar structure and is thought to facilitate cartilage movement for biomedical applications, just like in bearing systems. Hyaluronic acid (HA) is one of the natural polymers that can be used to transport boron nitride and maintain its presence in joints for a long time. In this study, hybrid hydrogels were formulated by using boron nitride nanoparticles and nanosheets. The rheological properties of the hydrogels were evaluated according to the structural differences of hBN. Characterizations have shown that hybrid hydrogels can be produced in injectable form, and the rheological properties are strongly related to the structural properties of the added particle. It has been determined that hBN added to the hydrogel structure reduces the dynamic viscosity of the zero-shear point and the deformation rate of the hydrogel and also changes the viscoelastic properties of the hydrogel depending on boron nitride's structural differences. The suggested mechanism is the hybrid hydrogel that exhibits lower viscosity as the layers detach from each other or disperses the agglomerates under applied shear stress. hBN, which has been proposed as a new strategy for joint injections, is thought to be a promising candidate for the treatment of OA due to its lamellar structures.

Injectable hydrogels: An emerging therapeutic strategy for cartilage regeneration

The impairment of articular cartilage due to traumatic incidents or osteoarthritis has posed significant challenges for healthcare practitioners, researchers, and individuals suffering from these conditions. Due to the absence of an approved treatment strategy for the complete restoration of cartilage defects to their native state, the tissue condition often deteriorates over time, leading to osteoarthritic (OA). However, recent advancements in the field of regenerative medicine have unveiled promising prospects through the utilization of injectable hydrogels. This versatile class of biomaterials, characterized by their ability to emulate the characteristics of native articular cartilage, offers the distinct advantage of minimally invasive administration directly to the site of damage. These hydrogels can also serve as ideal delivery vehicles for a diverse range of bioactive agents, including growth factors, anti-inflammatory drugs, steroids, and cells. The controlled release of such biologically active molecules from hydrogel scaffolds can accelerate cartilage healing, stimulate chondrogenesis, and modulate the inflammatory microenvironment to halt osteoarthritic progression. The present review aims to describe the methods used to design injectable hydrogels, expound upon their applications as delivery vehicles of biologically active molecules, and provide an update on recent advances in leveraging these delivery systems to foster articular cartilage regeneration.

Ex Vivo Functional Benchmarking of Hyaluronan-Based Osteoarthritis Viscosupplement Products: Comprehensive Assessment of Rheological, Lubricative, Adhesive, and Stability Attributes

While many injectable viscosupplementation products are available for osteoarthritis (OA) management, multiple hydrogel functional attributes may be further optimized for efficacy enhancement. The objective of this study was to functionally benchmark four commercially available hyaluronan-based viscosupplements (Ostenil, Ostenil Plus, Synvisc, and Innoryos), focusing on critical (rheological, lubricative, adhesive, and stability) attributes. Therefore, in vitro and ex vivo quantitative characterization panels (oscillatory rheology, rotational tribology, and texture analysis with bovine cartilage) were used for hydrogel product functional benchmarking, using equine synovial fluid as a biological control. Specifically, the retained experimental methodology enabled the authors to robustly assess and discuss various functional enhancement options for hyaluronan-based hydrogels (chemical cross-linking and addition of antioxidant stabilizing agents). The results showed that the Innoryos product, a niacinamide-augmented linear hyaluronan-based hydrogel, presented the best overall functional behavior in the retained experimental settings (high adhesivity and lubricity and substantial resistance to oxidative degradation). The Ostenil product was conversely shown to present less desirable functional properties for viscosupplementation compared to the other investigated products. Generally, this study confirmed the high importance of formulation development and control methodology optimization, aiming for the enhancement of novel OA-targeting product critical functional attributes and the probability of their clinical success. Overall, this work confirmed the tangible need for a comprehensive approach to hyaluronan-based viscosupplementation product functional benchmarking (product development and product selection by orthopedists) to maximize the chances of effective clinical OA management.

Hyaluronic Acid-Based Injective Medical Devices: In Vitro Characterization of Novel Formulations Containing Biofermentative Unsulfated Chondroitin or Extractive Sulfated One with Cyclodextrins

Currently, chondroitin sulfate (CS) and hyaluronic acid (HA) pharma-grade forms are used for osteoarthritis (OA) management, CS as an oral formulations component, and HA as intra-articular injective medical devices. Recently, unsulfated chondroitin, obtained through biofermentative (BC) manufacturing, has been proposed for thermally stabilized injective preparation with HA. This study aimed to highlight the specific properties of two commercial injective medical devices, one based on HA/BC complexes and the other containing HA, extractive CS, and cyclodextrins, in order to provide valuable information for joint disease treatments. Their biophysical and biomechanical features were assayed; in addition, biological tests were performed on human pathological chondrocytes. Rheological measurements displayed similar behavior, with a slightly higher G' for HA/BC, which also proved superior stability to the hyaluronidase attack. Both samples reduced the expression of specific OA-related biomarkers such as NF-kB, interleukin 6 (IL-6), and metalloprotease-13 (MMP-13). Moreover, HA/BC better ensured chondrocyte phenotype maintenance by up-regulating collagen type 2A1 (COLII) and aggrecan (AGN). Notwithstanding, the similarity of biomolecule components, the manufacturing process, raw materials characteristics, and specific concentration resulted in affecting the biomechanical and, more interestingly, the biochemical properties, suggesting potential better performances of HA/BC in joint disease treatment.

Interventional Techniques for the Management of Knee Osteoarthritis: A Literature Review

Osteoarthritis of the knee is a prevalent condition that causes pain, discomfort, and disability that can severely impact the quality of life. This literature review aims to review the various interventional pain management techniques available to treat knee osteoarthritis. It analyzes the efficacy of various interventions such as intra-articular corticosteroids, prolotherapy, viscosupplementation, platelet-rich plasma, and genicular nerve blocks with radiofrequency ablation or cryoneurolysis. We searched databases for studies published in the past 20 years. A total of 37 articles were included. The literature supports the idea that a comprehensive treatment plan consisting of the various aforementioned techniques can provide relief for patients while delaying or avoiding joint replacement surgery.

Current Approaches to Four Challenging Pain Syndromes

During a conference of pain specialists, some of the experts addressed the potential management of four prevalent but difficult painful conditions, namely, chronic postsurgical pain (CPSP), knee osteoarthritis, chest trauma, and facet joint arthropathy. In all cases, the conditions posed challenges in accurate diagnoses as well as safe, effective treatments, especially using locoregional blocks. It is not clear why some surgical patients develop CPSP and others do not, although some risk factors have been identified. More importantly, the transitional phase of pain from acute to chronic deserves greater scrutiny. It appears as if more aggressive and more effective perioperative and postoperative analgesia could help mitigate or possibly prevent CPSP. Knee osteoarthritis is prevalent but is often managed pharmacologically and then with joint replacement; many patients simply live with the condition which can be viewed as a disease of the entire joint. New approaches with intra-articular injections of hyaluronic acid, platelet-rich plasma, and botulinum toxin may provide safe, effective, and durable pain control. Chest trauma can be extremely painful and a source of morbidity, but its management tends to rely on watchful waiting and drug therapy. New approaches to regional nerve blocks can be beneficial and may reduce troublesome symptoms such as the inability to cough or clear the lungs. Facet joint arthropathy is very prevalent among older people but is not completely clarified. It may be the source of intense pain with limited management strategies. The role of nerve blocks in facet joint arthropathy is an important new addition to the armamentarium of pain management, particularly for geriatric patients.

Viscoelasticity of Liposomal Dispersions

Janus-faced viscoelastic gelling agents-possessing both elastic and viscous characteristics-provide materials with unique features including strengthening ability under stress and a liquid-like character with lower viscosities under relaxed conditions. The mentioned multifunctional character is manifested in several body fluids such as human tears, synovial liquids, skin tissues and mucins, endowing the fluids with a special physical resistance property that can be analyzed by dynamic oscillatory rheology. Therefore, during the development of pharmaceutical or cosmetical formulations-with the intention of mimicking the physiological conditions-rheological studies on viscoelasticity are strongly recommended and the selection of viscoelastic preparations is highlighted. In our study, we aimed to determine the viscoelasticity of various liposomal dispersions. We intended to evaluate the impact of lipid concentration, the presence of cholesterol or 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and the gelling agents polyvinyl alcohol (PVA) and hydroxyethylcellulose (HEC) on the viscoelasticity of vesicular systems. Furthermore, the effect of two model drugs (phenyl salicylate and caffeine) on the viscoelastic behavior of liposomal systems was studied. Based on our measurements, the oscillation rheological properties of the liposomal formulations were influenced both by the composition and the lamellarity/size of the lipid vesicles.

Clinical and radiological efficacy of single-dose intra-articular high-molecular-weight hyaluronic acid in knee osteoarthritis

Context

While visco-supplementation is being used for the treatment of knee osteoarthritis (OA), the published reports vary widely in benefits afforded by this treatment. It was therefore proposed to assess the objective parameters along with subjective outcomes.

Aims

Our study assessed the radiological and clinical efficacy of single-dose high-molecular-weight intra-articular hyaluronic acid (HMW-IAHA) injection in knee OA.

Settings and Design

This interventional cohort study was conducted in a calculated sample size of 44 patients with knee OA.

Materials and Methods

Visual analog scale (VAS) and knee OA and outcome score (KOOS) were used for clinical assessment, and whole organ magnetic resonance imaging score (WORMS) for radiological assessment. The subjects were given a single dose of HMW-IAHA injection, 90 mg/3 ml, and were assessed on day 0 and day 90.

Statistical Analysis

Statistical Package for Social Sciences (SPSS) software was used.

Results

At the day 90 follow-up, there was an improvement in mean ± standard deviation values of VAS score (day 0: 8.53 ± 0.81, day 90: 5.97 ± 0.87), KOOS score (day 0: 27.33 ± 15.18, day 90: 57.26 ± 14.26), and the cartilage signal and morphology in the medial femorotibial joint (day 0: 11.02 ± 6.26 and day 90: 10.91 ± 6.22) and patellofemoral joint (day 0: 10.35 ± 4.36 and day 90: 10.28 ± 4.39) compartments. There was a decrease in synovitis score from 2.3 ± 1.61 to 1.3 ± 1.3 in the medial femorotibial joint compartment and total WORMS score (day 0: 66.57 ± 36.06, day 90: 65.14 ± 35.62).

Conclusions

A single dose of intra-articular injection with high-molecular-weight hyaluronic acid produces improvement in the clinical symptoms and quality of life as well as is effective in maintaining the articular cartilage integrity and reducing synovial inflammation.

Hyaluronic Acid: A Powerful Biomolecule with Wide-Ranging Applications-A Comprehensive Review

Hyaluronic acid (HA) is a glycosaminoglycan widely distributed in the human body, especially in body fluids and the extracellular matrix of tissues. It plays a crucial role not only in maintaining tissue hydration but also in cellular processes such as proliferation, differentiation, and the inflammatory response. HA has demonstrated its efficacy as a powerful bioactive molecule not only for skin antiaging but also in atherosclerosis, cancer, and other pathological conditions. Due to its biocompatibility, biodegradability, non-toxicity, and non-immunogenicity, several HA-based biomedical products have been developed. There is an increasing focus on optimizing HA production processes to achieve high-quality, efficient, and cost-effective products. This review discusses HA's structure, properties, and production through microbial fermentation. Furthermore, it highlights the bioactive applications of HA in emerging sectors of biomedicine.

3D Bioprinting of Hyaline Articular Cartilage: Biopolymers, Hydrogels, and Bioinks

The musculoskeletal system, consisting of bones and cartilage of various types, muscles, ligaments, and tendons, is the basis of the human body. However, many pathological conditions caused by aging, lifestyle, disease, or trauma can damage its elements and lead to severe disfunction and significant worsening in the quality of life. Due to its structure and function, articular (hyaline) cartilage is the most susceptible to damage. Articular cartilage is a non-vascular tissue with constrained self-regeneration capabilities. Additionally, treatment methods, which have proven efficacy in stopping its degradation and promoting regeneration, still do not exist. Conservative treatment and physical therapy only relieve the symptoms associated with cartilage destruction, and traditional surgical interventions to repair defects or endoprosthetics are not without serious drawbacks. Thus, articular cartilage damage remains an urgent and actual problem requiring the development of new treatment approaches. The emergence of biofabrication technologies, including three-dimensional (3D) bioprinting, at the end of the 20th century, allowed reconstructive interventions to get a second wind. Three-dimensional bioprinting creates volume constraints that mimic the structure and function of natural tissue due to the combinations of biomaterials, living cells, and signal molecules to create. In our case-hyaline cartilage. Several approaches to articular cartilage biofabrication have been developed to date, including the promising technology of 3D bioprinting. This review represents the main achievements of such research direction and describes the technological processes and the necessary biomaterials, cell cultures, and signal molecules. Special attention is given to the basic materials for 3D bioprinting-hydrogels and bioinks, as well as the biopolymers underlying the indicated products.

Thermo-Responsive Hyaluronan-Based Hydrogels Combined with Allogeneic Cytotherapeutics for the Treatment of Osteoarthritis

Thermo-responsive hyaluronan-based hydrogels and FE002 human primary chondroprogenitor cell sources have both been previously proposed as modern therapeutic options for the management of osteoarthritis (OA). For the translational development of a potential orthopedic combination product based on both technologies, respective technical aspects required further optimization phases (e.g., hydrogel synthesis upscaling and sterilization, FE002 cytotherapeutic material stabilization). The first aim of the present study was to perform multi-step in vitro characterization of several combination product formulas throughout the established and the optimized manufacturing workflows, with a strong focus set on critical functional parameters. The second aim of the present study was to assess the applicability and the efficacy of the considered combination product prototypes in a rodent model of knee OA. Specific characterization results (i.e., spectral analysis, rheology, tribology, injectability, degradation assays, in vitro biocompatibility) of hyaluronan-based hydrogels modified with sulfo-dibenzocyclooctyne-PEG4-amine linkers and poly(N-isopropylacrylamide) (HA-L-PNIPAM) containing lyophilized FE002 human chondroprogenitors confirmed the suitability of the considered combination product components. Specifically, significantly enhanced resistance toward oxidative and enzymatic degradation was shown in vitro for the studied injectable combination product prototypes. Furthermore, extensive multi-parametric (i.e., tomography, histology, scoring) in vivo investigation of the effects of FE002 cell-laden HA-L-PNIPAM hydrogels in a rodent model revealed no general or local iatrogenic adverse effects, whereas it did reveal some beneficial trends against the development of knee OA. Overall, the present study addressed key aspects of the preclinical development process for novel biologically-based orthopedic combination products and shall serve as a robust methodological basis for further translational investigation and clinical work.

Ozone Therapy versus Hyaluronic Acid Injections for Pain Relief in Patients with Knee Osteoarthritis: Preliminary Findings on Molecular and Clinical Outcomes from a Randomized Controlled Trial

Ozone therapy (OT) is used for the treatment of multiple musculoskeletal disorders. In recent years, there has been a growing interest in its use for the treatment of osteoarthritis (OA). The aim of this double-blind randomized controlled trial was to evaluate the efficacy of OT compared with hyaluronic acid (HA) injections for pain relief in patients with knee OA. Patients with knee OA for at least three months were included and randomly assigned to receive three intra-articular injections of ozone or HA (once a week). Patients were assessed at baseline and at 1, 3, and 6 months after the injections for pain, stiffness, and function using the WOMAC LK 3.1, the NRS, and the KOOS questionnaire. Out of 55 patients assessed for eligibility, 52 participants were admitted to the study and randomly assigned into the 2 groups of treatment. During the study, eight patients dropped out. Thus, a total of 44 patients, reached the endpoint of the study at 6 months. Both Group A and B consisted of 22 patients. At 1-month follow-up after injections, both treatment groups improved statistically significantly from baseline in all outcomes measured. At 3 months, improvements remained similarly consistent for Group A and Group B. At 6-month follow-up, the outcomes were comparable between the 2 groups, showing only a worsening trend in pain. No significant differences were found between the two groups in pain scores. Both therapies have proven to be safe, with the few recorded adverse events being mild and self-limiting. OT has demonstrated similar results to HA injections, proving to be a safe approach with significant effects on pain control in patients affected by knee OA. Due to its anti-inflammatory and analgesic effects, ozone might be considered as a potential treatment for OA.

Efficacy and Safety of Intra-Articular Cross-Linked Sodium Hyaluronate for the Treatment of Knee Osteoarthritis: A Prospective, Active-Controlled, Randomized, Parallel-Group, Double-Blind, Multicenter Study

The safety and efficacy of Hyruan ONE (test product), an intra-articular cross-linked sodium hyaluronate injection, to treat mild-to-moderate knee osteoarthritis was compared with that of Durolane (comparator) in a prospective, active-controlled, parallel-group, double-blind (masked-observed), multicenter non-inferiority study. European patients (n = 284) were randomized 1:1 (test product:comparator) and received one injection of cross-linked hyaluronic acid (60 mg/3 mL). In total, 280 patients completed the study. The primary endpoint of mean change in Western Ontario and McMaster University (WOMAC)-Likert Pain sub-scores from baseline at week 13 revealed changes of -5.59 and -5.54 for the test and comparator groups, respectively, demonstrating non-inferiority of the test product (difference, -0.05 [95% confidence interval, -0.838 to 0.729]). Secondary endpoint results, which included changes in WOMAC-Likert Pain sub-score from baseline to 26 weeks post-injection and changes in WOMAC-Likert Total score and Physical Function and Stiffness sub-scores, changes in patients' and investigators' global assessments, use of rescue medication, and responder rates at 13 and 26 weeks post-injection were similar between the groups. Incidence of adverse events was also similar. In both groups, most treatment-emergent adverse events were mild/moderate. Hyruan ONE was non-inferior to the comparator at 13 weeks post-injection in European patients with mild-to-moderate knee osteoarthritis.