The mechanism of action for hyaluronic acid treatment in the osteoarthritic knee: a systematic review

Molecular signaling pathways in osteoarthritis and biomaterials for cartilage regeneration: a review

Osteoarthritis is a prevalent degenerative joint disease characterized by cartilage degradation, synovial inflammation, and subchondral bone alterations, leading to chronic pain and joint dysfunction. Conventional treatments provide symptomatic relief but fail to halt disease progression. Recent advancements in biomaterials, molecular signaling modulation, and gene-editing technologies offer promising therapeutic strategies. This review explores key molecular pathways implicated in osteoarthritis, including fibroblast growth factor, phosphoinositide 3-kinase/Akt, and bone morphogenetic protein signaling, highlighting their roles in chondrocyte survival, extracellular matrix remodeling, and inflammation. Biomaterial-based interventions such as hydrogels, nanoparticles, and chitosan-based scaffolds have demonstrated potential in enhancing cartilage regeneration and targeted drug delivery. Furthermore, CRISPR/Cas9 gene editing holds promise in modifying osteoarthritis-related genes to restore cartilage integrity. The integration of regenerative biomaterials with precision medicine and molecular therapies represents a novel approach for mitigating osteoarthritis progression. Future research should focus on optimizing biomaterial properties, refining gene-editing efficiency, and developing personalized therapeutic strategies. The convergence of bioengineering and molecular science offers new hope for improving joint function and patient quality of life in osteoarthritis management.

Large Variations in Resistance to Degradation between Hyaluronic Acid Viscosupplements: A Comparative Rheological Study

Intra-articular injections of hyaluronic acid (HA) are widely used in the treatment of osteoarthritis. HA half-life varies between products which might explain differences in effectiveness between viscosupplements.AimTo compare the resistance to degradation of linear and cross-linked viscosupplements using a rheological model combining mechanical and oxidative stresses, mimicking what happens inside the joint following HA injection.MethodsThe rheological properties of 8 HAs were measured using a stress-imposed Rheometer DHR3. Strain sweeps were carried out to evaluate the rheological properties at rest from 0.001 to 3000% at a frequency of 1 Hz. The complex modulus G*, in Pa, and the phase tangent tan δ, dimensionless, in the linear viscoelastic domain (LVED) were extracted. The oxidation tests were conducted by exposing the product to H2O2 for 30 minutes. The effect of oxidation was evaluated by measuring variations of G* and tan δ, using an oscillation time sweep. Those tests were carried out at a frequency of 1 Hz and at 1% strain in the LVED.ResultsAt rest, the different samples exhibited various viscous behaviors. During mixing process, G* decreased from -6.4% to -31.3%. G* of low-molecular-weight HAs decreased more than that of medium molecular weight (MW) and cross-linked products. After oxidative stress, G* variation ranged from -10.1% to -46.3%. Cross-linked HAs and those containing mannitol resisted the best to degradation.ConclusionsWe showed large variations in resistance to degradation between viscosupplements. The duration of effectiveness of these products deserves to be compared in randomized clinical studies.

Intra-articular hyaluronic acid injections for hip osteoarthritis: a level I systematic review

PURPOSE

The present systematic review investigated the efficacy of intra-articular hyaluronic acid (HA) viscosupplementation for hip osteoarthritis (OA) in patient-reported outcome measures (PROMs) and whether different molecular weights of HA are associated with different outcomes.

METHODS

This study was conducted according to the 2020 PRISMA statement. In January 2025, PubMed, Web of Science, Google Scholar, and Embase were accessed. All the randomised controlled trials (RCTs) evaluating the efficacy of intra-articular HA injections in the hip for OA were included.

RESULTS

Nine hundred and eighty-two patients (56% women, mean age 62.2 ± 4.0 years, mean follow-up 6.4 ± 2.7 months, mean BMI 27.5 ± 2.1 kg/m2) were analysed. Patients receiving high molecular weight (HMW) and low molecular weight (LMW) HA showed significant improvements in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analogue scale (VAS) scores (P < 0.05). No significant differences in VAS or WOMAC were observed among groups at 3-4 months of follow-up. However, at 4-6 months, the HMW HA group exhibited significantly lower VAS scores compared to the medium molecular weight (MMW) (mean difference, MD - 1.4, 95% CI - 2.1 to - 0.7, P < 0.0001), placebo (MD - 1.6, 95% CI - 2.1 to - 1.1, P < 0.0001), and control (MD - 1.3, 95% CI - 1.8 to - 0.8, P < 0.0001) groups. WOMAC scores at 4-6 months demonstrated that both HMW and MMW HA performed better than the control group (P < 0.0001), but no significant difference was observed between HMW and MMW (P = 1.0).

CONCLUSION

Intra-articular injections of HA effectively reduce knee OA symptoms. Moreover, HMW HA performs better than MMW HA at a mean of 4-6 months of follow-up.

LEVEL OF EVIDENCE

Level I, systematic review of RCTs.

Advances and principles of hyaluronic acid production, extraction, purification, and its applications: A review

Hyaluronic acid (HA) is a linear, unbranched polysaccharide composed of repeating disaccharide units of N-acetyl-d-glucosamine and D-glucuronic acid. It plays a crucial role in promoting soft tissue growth, elasticity, and scar reduction. The growing demand for HA in pharmaceutical and cosmetic applications has provoked extensive research into diverse production strategies. Current efforts focus on bacterial and yeast fermentation. However, the extraction process presents a significant challenge due to the complex nature of source materials like fermentation broth, which contains numerous components and solutes. Achieving high extraction yields and purity requires careful consideration of extraction techniques. This study provides a comprehensive overview of the primary methodologies employed for HA production, elaborating on the advantages and disadvantages of each approach. Additionally, it highlights recent advancements in HA extraction and purification, with a particular emphasis on bacterial sources and the applications of HA. This review critically evaluates current HA production strategies, identifies key challenges hindering scalability and efficiency, and discusses innovative solutions under development to overcome these limitations.

Comparison between two viscosupplementation protocols for temporomandibular joint osteoarthritis

OBJECTIVE

This clinical trial aimed to compare the efficacy of two protocols using high molecular weight hyaluronic acid (HA) intra-articular injection in patients with temporomandibular joint (TMJ) osteoarthritis and evaluate involvement of subchondral bone changes and psychosocial factors as predictors of HA treatment.

METHODS

Twenty-one individuals were divided into two groups: (A) received three intra-articular HA injections, and (B) received one injection. Outcomes observed were pain intensity, functional limitation, maximum voluntary mouth opening, maximum assisted mouth opening, and treatment tolerability. Follow-ups were performed weekly for 21 days, and two months after the treatment started.

RESULTS

No statistically significant intergroup differences were observed in any of the evaluated outcomes. However, Group A showed significant improvement in all outcomes, whereas Group B showed significant improvement only in pain intensity and functional limitation.

CONCLUSION

This study demonstrated the effectiveness of both protocols in terms of pain intensity and functional limitation caused by osteoarthritis.

Quantitative analysis of the efficacy and associated factors of intra-articular hyaluronic acid with respect to osteoarthritis symptoms: A systematic review of randomized trials and model-based meta-analysis

OBJECTIVE

To quantitatively evaluate hyaluronic acid (HA) efficacy for osteoarthritis (OA) and identify potential responders who would benefit most from HA.

METHOD

Embase, MEDLINE (PubMed), and the Cochrane Library Central Register of Controlled Trials were searched from inception to March 13, 2023. A pharmacodynamic Bateman function model was used to quantitatively evaluate the efficacy characteristics of HA treatments as well as placebo, while a covariate model was employed to identify factors that significantly affected efficacy.

RESULTS

In total, 24 101 participants with symptomatic or radiographic OA from 168 studies with aggregate data were included. Simulation analysis from the pharmacodynamic time-effect model showed that HA treatment effects plateaued at approximately 2 months. The final model analysis indicated that intra-articular injection of HA combined with corticosteroids (CS) (the Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] pain effect size [ES] = 4.4 [95% confidence interval {CI}: 3.0 to 5.7]) or platelet-rich plasma (PRP) (WOMAC pain ES = 4.0 [95% CI: 2.7 to 5.3]) achieved the best efficacy compared with other groups (contrast between meta-analyses: WOMAC pain ES = 1.9 [95% CI: 1.2 to 5.2]). Subgroups analysis showed that younger (age < 65), overweight (body mass index ≥ 25) knee OA patients, with more severe baseline symptoms and a lower Kellgren-Lawrence (KL) grade (≤ 2), could benefit more.

CONCLUSION

The quantitative model suggested that HA interventions were statistically more effective than placebo, with participants receiving HA+ CS or PRP experiencing the best efficacy. Patients with lower age, higher weight, higher severity of baseline symptoms, and lower KL grade appeared to benefit more from HA treatment.

Hyaluronic acid-silybin conjugate for the preparation of multifunctional, biomimetic, vancomycin-loaded self-assembled polymersomes against bacterial sepsis

Sepsis, a life-threatening disruption, remains a significant global healthcare challenge that urgently needs novel strategies to improve management. This study aimed to develop multifunctional vancomycin-loaded polymersomes (VCM-HA-SIL-Ps) using a novel hyaluronic acid-silybin (HA-SIL) conjugate to target the TLR inflammatory pathway and enhance VCM's efficacy against bacterial sepsis. HA-SIL was synthesized and characterized by FT-IR, UV-Vis spectroscopy, and 1H NMR. The biomimetic properties of HA-SIL were confirmed via in silico (-73.35 kcal/mol) and in vitro (dissociation constant = 2.872 μM) binding affinity studies against TLR2. VCM-HA-SIL-Ps exhibited appropriate physicochemical properties, biocompatibility, and stability. VCM-HA-SIL-Ps sustained VCM release for 48 h, achieving 73.38 % cumulative release. In vitro antibacterial studies showed that VCM-HA-SIL-Ps had superior minimum inhibitory concentration against sensitive and resistant Staphylococcus aureus and faster bacterial killing, compared to free VCM. Additionally, VCM-HA-SIL-Ps demonstrated excellent DPPH radicals scavenging and effective anti-inflammatory activity on bacterial toxin-stimulated cells. Finally, in a mouse model of MRSA-induced sepsis, VCM-HA-SIL-Ps achieved 100 % bacterial eradication, significantly reduced pro-inflammatory markers (IL-6, TNF-α, IL-1β by 2.9-, 1.8-, and 5-fold, respectively), and minimized organ damage. Collectively, these findings demonstrate the potential of HA-SIL as a novel multifunctional adjuvant for effective antibiotic delivery against bacterial sepsis.

Mechanisms of Action of Intra-articular Hyaluronic Acid Injections for Knee Osteoarthritis: A Targeted Review of the Literature

BACKGROUND

The knee is the most commonly afflicted joint in osteoarthritis (OA). Injection of intra-articular of hyaluronic acid (IAHA) is a frequently used therapy for the management of knee OA with varying product characteristics.

PURPOSE

To describe and characterize the mechanism of action (MoA) of IAHA products concerning nociception, chondroprotection, and anti-inflammatory properties via a targeted literature review.

STUDY DESIGN

Systematic review; Level of evidence, 2.

METHODS

We followed the standard methodologies for conducting and reporting targeted reviews as recommended by the Cochrane Handbook for Systematic Reviews of Interventions, adapted for conducting a targeted literature review. Relevant studies were identified by searching the Embase database using predefined search strategies via the Ovid platform. The results of the review were reported according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses).

RESULTS

A total of 182 studies were included in this targeted literature review. Of these, 107 reported chondroprotective action, 59 anti-inflammatory activity, 18 analgesic properties, 30 proteoglycan or glycosaminoglycan synthesis, 8 subchondral bone effects, 2 mechanical effects, and 1 other effects of IAHA. These MoAs were studied through diverse types of studies: in vitro biochemistry, animal physiological studies, or human physiological and clinical studies. The chondroprotective effect was the most studied MoA and showed an increase in anabolic biomarkers, such as collagen types II, IX, and XI, and a reduction in catabolic biomarkers, such as matrix metalloproteinases, which play a primary role in the downstream signaling pathways in OA and cartilage degradation in the synovial fluid. IAHA was widely reported by studies to reduce soluble inflammatory mediators, such as interleukins 1β and 6 and tumor necrosis factor α, thereby decreasing the production of degradative enzymes (eg, matrix metalloproteinases, aggrecanases). IAHA was also reported to enhance the synthesis of intrinsic proteoglycan (eg, aggrecan) and glycosaminoglycans, thus delaying the progression of OA. IAHA also reported improvement in the mechanical function of the knee by increasing the viscosity of the synovial fluid, reducing the coefficient of friction, and improving its lubrication. Overall, a significant decrease in knee pain was observed after IAHA treatments.

CONCLUSION

Preclinical and clinical studies established evidence for varied MoAs by which IAHA preparations may produce a desired effect in patients with knee OA.

The Current Status and Future Prospects of Intra-articular Injection Therapy for Hip Osteoarthritis: A Review

PURPOSE OF REVIEW

Hip osteoarthritis constitutes a prevalent condition among individuals aged 55 and above, serving as one of the primary triggers for joint discomfort and impairment, and marking a substantial origin of chronic pain particularly affecting the elderly population. Our article provides an exhaustive summary of the mechanisms of action, therapeutic efficacy, and potential adverse consequences associated with novel therapeutic modalities including glucocorticoids, hyaluronic acid, platelet-rich plasma, mesenchymal stem cells, and stromal vascular fraction. Concurrently, we conducted a comprehensive evaluation of the clinical efficacy and potential applications of various medications.

RECENT FINDINGS

In comparison to physical therapy, oral analgesics, and other nonsurgical modalities, intra-articular injection therapy is characterized by enhanced safety and greater efficacy. Moreover, when contrasted with surgical intervention, intra-articular injection demonstrates a lower degree of invasiveness and incurs fewer adverse reactions. Intra-articular treatments have shown excellent local efficacy while significantly minimizing adverse reactions in patients. These methods hold significant potential for development but require comprehensive research and thorough discussion within the academic community.

Intra-articular injections of hyaluronic acid versus plasma rich in growth factors (PRGF) for knee osteoarthritis: a meta-analysis of randomised controlled trials : A meta-analysis

INTRODUCTION

The present meta-analysis compared intra-articular injections of hyaluronic acid (HA) versus plasma rich in growth factors (PRGF) in patients with knee osteoarthritis (OA). The outcome of interest was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

METHODS

This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses: the 2020 PRISMA statement. All the head-to-head randomised controlled trials (RCT) comparing intra-articular HA injections versus PRGF were accessed and included in the present study. Only studies that clearly stated that injections were performed in patients with knee OA, irrespective of the severity of OA, were considered. Data concerning the WOMAC index were retrieved at baseline and last follow-up. The endpoint of interest was to investigate whether intra-articular HA injections are associated with WOMAC score improvement compared to PRGF injections at 4-6 months follow-up.

RESULTS

Data from 432 patients were collected and 76.3% (330 of 432) of the patients were women. The mean age of the patients was 58.2 ± 1.5 years and the mean body mass index (BMI) was 28.0 ± 0.5 kg/m2. At baseline, comparability in mean age, BMI, male:female ratio, WOMAC and related subscales were documented. The PRGF group evidenced lower values of the function subscale of the WOMAC index (P = 0.03). No difference was found in the overall WOMAC index (P = 0.05) and its stiffness (P = 0.4) and pain (P = 0.07) subscales.

CONCLUSION

The current level I evidence suggests that the use of PRGF might be associated with more favorable clinical outcomes than using HA.

Efficacy of new active viscosupplements on the behavior of an experimental model of osteoarthritis

OBJECTIVE

To evaluate with an animal model of osteoarthritis (New Zealand rabbits) the effectiveness of treatment with active viscosupplements (hyaluronic acid loaded with nanoparticles (NPs) that encapsulate anti-inflammatory compounds or drugs.

MATERIAL AND METHODS

Experimental study composed of 5 groups of rabbits in which section of the anterior cruciate ligament and resection of the internal meniscus were performed to trigger degenerative changes and use it as a model of osteoarthritis. The groups were divided into osteoarthrosis without treatment (I), treatment with commercial hyaluronic acid (HA) (II), treatment with HA with empty nanoparticles (III), treatment with HA with nanoparticles encapsulating dexamethasone (IV) and treatment with HA with nanoparticles that encapsulate curcumin (V). In groups II to V, the infiltration of the corresponding compound was carried out spaced one week apart. Macroscopic histological analysis was performed using a scale based on the Outerbridge classification for osteoarthritis.

RESULTS

We observed that this osteoarthritis model is reproducible and degenerative changes similar to those found in humans are observed. The groups that were infiltrated with hyaluronic acid with curcumin-loaded nanoparticles (V), followed by the dexamethasone group (IV) presented macroscopically less fibrillation, exposure of subchondral bone and sclerosis (better score on the scale) than the control groups (I) (osteoarthritis without treatment), group (II) treated with commercial hyaluronic acid and hyaluronic acid with nanoparticles without drug (III).

CONCLUSIONS

The use of active viscosupplements could have an additional effect to conventional hyaluronic acid treatment due to its antioxidant and anti-inflammatory effect. The most promising group was hyaluronic acid with nanoparticles that encapsulate curcumin and the second group was the one that encapsulates dexamethasone.

Hyaluronic acid injections administered within two months prior to total knee arthroplasty increase the risk for periprosthetic joint infection

BACKGROUND

It remains unknown how timing of preoperative intra-articular knee hyaluronic acid (HA) injections impacts risk for developing postoperative periprosthetic joint infection (PJI) following total knee arthroplasty (TKA).

METHODS

The PearlDiver Mariner database was utilized to identified patients undergoing primary TKA between 2015 and 2022 who received an HA injection without a corticosteroid injection within 12 months prior to surgery. The HA cohort was matched 1:1 to a control cohort undergoing no preoperative injections (corticosteroid or HA). Multivariable logistic regression analysis was utilized to determine the risk of preoperative HA injections on PJI at 1, 3, 6, 12, and 24 months postoperative. The following pre-operative intervals between injection and TKA were evaluated: 0-1 month, 1-2 months, 2-3 months, 4-6 months, and 7-12 months.

RESULTS

38,546 patients (HA: n = 19,273; Control: n = 19,273) were analyzed. HA injections within 1 month prior to surgery demonstrated significant increase in rates of PJI at 3-months (OR: 3.00, 95% CI: 1.29 - 6.47; p = 0.005), 6-months (OR: 2.66, 95% CI: 1.30 - 5.46; p = 0.007), 12-months (OR: 2.37, 95% CI: 1.20 - 4.67; p = 0.013), and 24-months (OR: 2.65, 95% CI: 1.50 - 4.68; p < 0.001) postoperatively. HA injections between 1-2 months prior to surgery showed increased rates of PJI at 12-months (OR: 1.60, 95% CI: 1.06-2.41; p = 0.011) postoperatively. No difference in infection risk was demonstrated between patients receiving injections > 2 months prior to surgery relative to matched controls.

CONCLUSIONS

Intra-articular hyaluronic acid injections administered within 2 months of TKA appear to increase the risk of PJI.

[Translated article] Efficacy of new active viscosupplements on the behaviour of an experimental model of osteoarthritis

OBJECTIVE

To evaluate with an animal model of osteoarthritis (New Zealand rabbits) the effectiveness of treatment with active viscosupplements (hyaluronic acid loaded with nanoparticles (NPs) that encapsulate anti-inflammatory compounds or drugs.

MATERIAL AND METHODS

Experimental study composed of 5 groups of rabbits in which section of the anterior cruciate ligament and resection of the internal meniscus were performed to trigger degenerative changes and use it as a model of osteoarthritis. The groups were divided into osteoarthrosis without treatment (I), treatment with commercial hyaluronic acid (HA) (II), treatment with HA with empty nanoparticles (III), treatment with HA with nanoparticles encapsulating dexamethasone (IV) and treatment with HA with nanoparticles that encapsulate curcumin (V). In groups II-V, the infiltration of the corresponding compound was carried out spaced one week apart. Macroscopic histological analysis was performed using a scale based on the Outerbridge classification for osteoarthritis.

RESULTS

We observed that this osteoarthritis model is reproducible and degenerative changes similar to those found in humans are observed. The groups that were infiltrated with hyaluronic acid with curcumin-loaded nanoparticles (V), followed by the dexamethasone group (IV) presented macroscopically less fibrillation, exposure of subchondral bone and sclerosis (better score on the scale) than the control groups (I) (osteoarthritis without treatment), group (II) treated with commercial hyaluronic acid and hyaluronic acid with nanoparticles without drug (III).

CONCLUSIONS

The use of active viscosupplements could have an additional effect to conventional hyaluronic acid treatment due to its antioxidant and anti-inflammatory effect. The most promising group was hyaluronic acid with nanoparticles that encapsulate curcumin and the second group was the one that encapsulates dexamethasone.

Efficacy and Safety of Intra-Articular Therapy with Cross-Linked Hyaluronic Acid in Patients with Knee Osteoarthritis

Background/Objectives: Knee osteoarthritis (OA) is a degenerative chronic disease characterized by a reduction in articular cartilage, as well as pain and functional limitations. We evaluated both the efficacy and safety of cross-linked high-molecular-weight hyaluronic acid in patients with knee OA. Methods: In this observational prospective single-arm study, a cross-linked high-molecular-weight hyaluronic acid (DIART ONE 90 mg in 3 mL) was administered in single injections to 50 patients aged 18-65 years, with a follow-up at 3, 6, and 12 months. Several scores were evaluated, including the Knee Injury and Osteoarthritis Outcome Score as the primary outcome measure and the Visual Analogue Scale, Timed Up and Go Test, Six-Minute Walking Test, General Health Assessment with 36-Item Short Form Health Survey, Zung's Self-Rating Anxiety Scale, and Zung's Self-Rating Depression Scale as secondary outcome measures. Both physicians and patients knew the kind of treatment they received. Results: During the follow-ups, we observed a statistically significant improvement in clinical scores at 3 and 6 months, with a decrease in clinical benefit at 12 months. Functional and psychological benefits were significant at 3, 6, and 12 months. No side effects were described except pain associated with the site of injection. Conclusions: In conclusion, we documented that cross-linked high-molecular-weight hyaluronic acid (DIART ONE 90 mg in 3 mL) represents an effective option in the management of mild-moderate osteoarthritis.

Lubrication for Osteoarthritis: From Single-Function to Multifunctional Lubricants

Osteoarthritis (OA) is a common degenerative joint disease that progressively destroys articular cartilage, leading to increased joint friction and severe pain. Therefore, OA can be treated by restoring the lubricating properties of cartilage. In this study, recent advances in lubricants for the treatment of OA are reviewed for both single-function and multifunctional lubricants. Single-function lubricants mainly include glycosaminoglycans, lubricin, and phospholipids, whereas multifunctional lubricants are composed of lubricating and anti-inflammatory bifunctional hydrogels, stem cell-loaded lubricating hydrogels, and drug-loaded lubricating nanoparticles. This review emphasizes the importance of restoring joint lubrication capacity for the treatment of OA and explores the structural features, lubrication properties, and role of these lubricants in modulating intracellular inflammatory responses and metabolism. Current challenges and future research directions in this field are also discussed, with the aim of providing a scientific basis and new ideas for the clinical treatment of OA.

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.

Efficacy of hyaluronic acid in temporomandibular disorders evaluated with diagnostic criteria for temporomandibular disorders (DC/TMD)

BACKGROUND

The study aimed to retrospectively assess the efficacy of hyaluronic acid (HA) in managing temporomandibular disorders (TMD) using the diagnostic criteria for temporomandibular disorders (DC/TMD). There has been an ongoing debate regarding the effectiveness of HA as a treatment option for TMD, which necessitated a thorough evaluation.

METHODS

The review adhered to PRISMA guidelines conducted across eight different databases, including PubMed, Embase, Web of Science, Cochrane Library, Scopus, ScienceDirect, PsycINFO and CINAHL. The selection criteria included studies that evaluated the efficacy of HA in TMD patients, utilised DC/TMD, and were published in English. Data extraction and quality assessment were performed independently by two reviewers. ROB-2 tool was employed to assess methodological quality of the assessed studies.

RESULTS

A total of 10 studies met the inclusion criteria. They demonstrated that HA was effective in improving various symptoms of TMD, such as pain, mouth opening and joint sounds over control group. But on the other end, platelet-rich plasma (PRP) was found to be better than HA intervention in alleviation of TMD symptoms. However, the degree of improvement varied across the studies. Some studies reported adverse effects, but these were typically minor and transient. Risk of bias assessment was low in all the included studies.

CONCLUSION

The findings suggest that HA can be an effective treatment for TMD when evaluated with DC/TMD. However, the variation in effectiveness across studies indicates the need for individualised treatment planning and careful monitoring of adverse effects. Further research is needed to refine the treatment protocols and understand the long-term effectiveness and safety of HA in TMD management.

Advances in Regenerative Medicine for Orthopedic Injuries: A Comprehensive Review

Orthopedics is one field that greatly benefits from the new ideas provided by regenerative medicine. This review pulls together the most recent publications involving stem cell therapy, platelet-rich plasma, growth factor, gene therapy, tissue engineering, stem cell-derived extracellular vesicles, and other regenerative technologies in the context of bone, cartilage, tendon, and ligament healing. Recent studies show that these new therapies can alter cell development, division, and production of fiber and ground substance to remodel tissues. Nevertheless, the clinical application has several issues such as the standardization of cell procurement and preparation, the control of cytokine/gene delivery, the revascularization of tissues, and the requirements of large samples, positively controlled clinical trials. More research must be conducted to overcome such barriers and make practicing more applicable in real life.

Recent advances in the management of knee osteoarthritis: a narrative review

Knee osteoarthritis (OA) is a common condition that causes pain and reduces the quality of life for many people. It also leads to high health and financial costs. Managing knee OA pain requires using different methods together for the best results. This review overviews current therapeutic options for knee OA pain, focusing on their efficacy, safety, and potential roles in clinical practice. Topical treatments, such as NSAIDs and capsaicin, offer significant pain relief with minimal systemic side effects and are suitable for initial therapy, together with nonpharmacologic interventions like exercise and, when relevant, weight loss. Oral analgesics, including acetaminophen and opioids, have limited efficacy and serious side effects, making them appropriate only for short-term or rescue therapy. Intra-articular injections, such as corticosteroids, hyaluronic acid, and platelet rich plasma, demonstrate varying levels of efficacy and safety. Nutritional supplements, including curcumin, Boswellia serrata, and glucosaminechondroitin combinations, offer modest benefits and are best used as adjuncts to standart treatment. Nonpharmacological treatments, such as transcutaneous electrical nerve stimulation (TENS), acupuncture, and local heat therapy, provide variable pain relief and should be customized based on individual patient responses. Targeted biologic agents, such as antibodies to TNF-α, IL-1, and NGF, hold promise for more precise pain relief; however, further research is required to establish their routine use. Treating knee OA pain should be personalized, combining several methods. Research must continue to improve treatments and make them safer.

Inducible engineering precursor metabolic flux for synthesizing hyaluronic acid of customized molecular weight in Streptococcus zooepidemicus

BACKGROUND

Hyaluronic acid (HA) is extensively employed in various fields such as medicine, cosmetics, food, etc. The molecular weight (MW) of HA is crucial for its biological functions. Streptococcus zooepidemicus, a prominent HA industrial producer, naturally synthetizes HA with high MW. Currently, few effective approaches exist for the direct and precise regulation of HA MW through a one-step fermentation process, and S. zooepidemicus lacks metabolic regulatory elements with varying intensities. The ratio of HA's precursors, UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-glucuronic acid (UDP-GlcA), is critical for the extension and release of HA. An imbalance in the precursor proportions for HA synthesis leads to a significant decrease in HA MW, indicating that controlling the precursor ratio may serve as a potential method for regulating HA MW.

RESULTS

In this study, the type and concentration of carbon sources were manipulated to disrupt the balance of precursor supply. Based on the results, it was speculated that the transcription level of hasE, which may connect the two HA synthesis precursors, is positively correlated with HA MW. Consequently, an endogenous expression component library for S. zooepidemicus was constructed, comprising 32 constitutive and 4 inducible expression elements. The expression of hasE was subsequently regulated in strain SE0 (S12 ΔhasE) using two constitutive promoters of differing strengths. The recombinant strain SE1, in which hasE was controlled by the stronger promoter PR31, produced HA with a MW of 1.96 MDa. In contrast, SE2, utilizing the weaker promoter PR22, synthesized shorter HA with a MW of 1.63 MDa, thereby verifying the hypothesis. Finally, to precisely regulate HA MW according to specific demands, an efficient sucrose-induced expression system was screened and employed to control the transcription level of hasE, obtaining recombinant strain SE3. When induced with sucrose concentrations of 3, 5-10 g/L, the HA MW of SE3 reached 0.78 to 1.77 MDa, respectively.

CONCLUSIONS

Studies on regulating the balance of the HA precursor substances indicate that an oversupply of either UDP-GlcNAc or UDP-GlcUA can reduce HA MW. The hasE gene serves as a crucial regulator for maintaining this balance. Precise regulation of hasE transcription was achieved through an efficient inducible expression system, enabling the customized production of HA with specific MW. The HA MW of strain SE3 can be accurately manipulated by adjusting sucrose concentration, establishing a novel strategy for customized HA fermentation.

Hyaluronic Acid-Based Drug Delivery Systems for Cancer Therapy

In recent years, hyaluronic acid (HA) has attracted increasing attention as a promising biomaterial for the development of drug delivery systems. Due to its unique properties, such as high biocompatibility, low toxicity, and modifiability, HA is becoming a basis for the creation of targeted drug delivery systems, especially in the field of oncology. Receptors for HA overexpressed in subpopulations of cancer cells, and one of them, CD44, is recognized as a molecular marker for cancer stem cells. This review examines the role of HA and its receptors in health and tumors and analyzes existing HA-based delivery systems and their use in various types of cancer. The development of new HA-based drug delivery systems will bring new opportunities and challenges to anti-cancer therapy.

In vivo impact on rabbit subchondral bone of viscosupplementation with a hyaluronic acid antioxidant conjugate

OBJECTIVE

This study aimed to assess the effects of an antioxidant-conjugated Hyaluronic Acid (HA), specifically HA-4-aminoresorcinol (HA4AR), on articular cartilage and subchondral bone in osteoarthritis (OA). We conducted a comparative analysis between HA4AR and a commercially available high molecular weight HA formulation in a rabbit model of OA.

MATERIALS AND METHODS

Eighteen rabbits underwent unilateral anterior cruciate ligament transection (ACLT) and were divided into three groups of six: Saline-group, HA-group, and HA4AR-group, based on the type of intra-articular injection received. Additionally, eight non-operated contralateral knees served as reference points (Contralateral-group). Six weeks post-surgery, iodine-enhanced micro-computed tomography imaging was used to evaluate articular cartilage volume and thickness, and to assess subchondral bone microarchitecture and mineral density.

RESULTS

Cartilage thickness in both the HA and HA4AR groups was comparable to that of the Contralateral group. Notably, there was a significant reduction in subchondral bone plate tissue mineral density in the HA-group when compared to both the HA4AR and Saline groups (p < 0.05). However, no significant differences in trabecular subchondral bone microarchitectural parameters and mineral densities were observed between the HA4AR-group and the Saline-group. When compared to the Contralateral, Saline, and HA4AR groups, the HA-group exhibited a marked decrease in subchondral bone plate tissue mineral density (p < 0.05). Additionally, a significant reduction in trabecular bone volume fraction was noted in the HA-group compared to the Contralateral-group (p < 0.05).

CONCLUSIONS

The HA-4AR hydrogel demonstrated significant preservation of subchondral bone plate tissue mineral density compared to HA alone, while other bone microarchitectural parameters remained largely unchanged. These findings indicate that HA-4AR may provide enhanced osteoprotective benefits in the treatment of osteoarthritis.

Similar efficacy of intra-articular hyaluronic acid injections and other biologically active injections in patients with early stages knee osteoarthritis: a level I meta-analysis

INTRODUCTION

The present meta-analysis compared the efficacy of intra-articular hyaluronic acid (HA) injections in patients with early to mild knee osteoarthritis (OA) (Kellgren Lawrence I-II) versus other commonly injected biologically active compounds using patient-reported outcome measures (PROMs). The outcomes of interest were the visual analogue scale (VAS) and the Western Ontario McMaster Osteo-Arthritis Index (WOMAC) scores.

METHODS

This study was conducted according to the 2020 PRISMA statement. In April 2024, PubMed, Web of Science, Google Scholar, and Embase were accessed without time constraints. All the randomised controlled trials (RCTs) investigating the efficacy of intra-articular HA injections in the early stages of knee OA were accessed. Data concerning the VAS, WOMAC, and related subscales were collected at baseline and the last follow-up. Only studies clearly stated the degrees of advancement of OA using the Kellgren-Lawrence scoring system were used.

RESULTS

The literature search resulted in four RCTs (390 patients). The mean length of the last follow-up was 7.5 ± 3.0 months. 72.3% (282 of 390) of the patients were women. The mean age of the patients was 58.1 ± 3.2 years, and the mean BMI was 27.3 ± 3.2 kg/m2. At the last follow-up, no difference was found between HA and the control group in VAS, WOMAC, and related subscales.

CONCLUSION

In patients with early to mild knee osteoarthritis, the current level of evidence suggests that intra-articular injections using HA performed similarly to other biologically active compounds commonly injected in the knee joint for a minimum of three months.

LEVEL OF EVIDENCE

Level I, meta-analysis.

An Advanced Mechanically Active Osteoarthritis-on-Chip Model to Test Injectable Therapeutic Formulations: The SYN321 Case Study

Current treatments for osteoarthritis (OA) often fail to address the underlying pathophysiology and may have systemic side effects, particularly associated with long-term use of non-steroidal anti-inflammatory drugs (NSAIDs). Thus, researchers are currently directing their efforts toward innovative polymer-drug combinations, such as mixtures of hyaluronic acid viscoelastic hydrogels and NSAIDs like diclofenac, to ensure sustained release of the NSAID within the joint following intra-articular injection. However, the progress of novel injectable therapies for OA is hindered by the absence of preclinical models that accurately represent the pathology of the disease. The uBeat® MultiCompress platform is here presented as a novel approach for studying anti-OA injectable therapeutics on human mechanically-damaged OA cartilage microtissues, in a physiologically relevant environment. This platform can accommodate injectable therapeutic formulations and is successfully tested with SYN321, a novel diclofenac-sodium hyaluronate conjugate under development as a treatment for knee OA. Results indicate the platform's effectiveness in evaluating therapeutic potential, showing downregulation of inflammatory markers and reduction in matrix degradation in OA cartilage micro-tissues treated with SYN321. The uBeat® MultiCompress platform thus represents a valuable tool for OA research, offering a bridge between traditional in vitro studies and potential clinical applications, with implications for future drug discovery.

Oral Hyaluronic Acid in Osteoarthritis and Low Back Pain: A Systematic Review

Background

Hyaluronic acid (HA) has been largely used in clinical practice for rheumatic diseases. However, the effects of oral HA on these diseases are poorly understood.

Aim

To review articles evaluating oral HA's effects on rheumatic patients.

Methods

PubMed was searched for articles on oral HA and rheumatic diseases between 1966 and May 2024.

Results

Eleven articles were found with 597 patients. The diseases investigated were OA (n=10) and low back pain (n=1). Age varied from 40 to 70 years old, and female gender ranged from 43% to 75%. Follow-up ranged from 4 weeks to 12 months. The oral HA dosage varied from 30 mg to 300 mg/day. Concerning outcome, 9/11 articles observed improvement in rheumatic diseases in the following parameters: VAS pain, WOMAC, joint function, SF-36, Lequesne index, and stiffness. Two studies evaluated cytokines and observed a reduction of them after oral HA therapy. Adverse effects were rare and mild.

Conclusion

Oral HA seems to be a safe and effective therapy for OA and low back pain patients, although more studies should be done on the latter condition.

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.

Current Concepts in Orthobiologics for Achilles Tendon Injuries: A Critical Analysis Review

» Platelet-rich plasma and hyaluronic acid are low-risk and potentially high-reward treatments for Achilles tendinopathy, although clinical studies have yielded mixed results with questionable methodological quality» Case series and reports have reported that bone marrow aspirate, stem cells, and amniotic membrane products can improve functional outcomes, alleviate pain, and facilitate return to sport and activities, but high-level evidence studies are lacking» Exosomes are a promising novel biologic with laboratory studies showing improved collagen organization and cell proliferation, greater tendon mechanical properties, and prevention of extracellular matrix breakdown.» Standardization of protocols with clear reporting is necessary for future studies evaluating orthobiologic therapies for Achilles tendon injuries.

Efficacy of intra-articular injection of combined platelet-rich-plasma (PRP) and hyaluronic acid (HA) in knee degenerative joint disease: a prospective, randomized, double-blind clinical trial

PURPOSE

Intra-articular injections of hyaluronic acid (HA) and platelet-rich plasma (PRP) represent promising options in the conservative treatment of early stages of knee osteoarthritis (OA). Although the combined use of these two compounds seems to have a synergistic effect in pre-clinical studies, few clinical trials compared the association of PRP and HA with PRP and HA alone. The aim of study is to evaluate the efficacy of combined intra-articular injections of PRP and HA in the treatment of mild to moderate knee OA, compared to PRP and HA alone.

METHODS

One hundred and seventy-four patients were prospectively enrolled and randomized to undergo three intra-articular injections of either HA or PRP or the combination of PRP and HA with a two-week interval period. Patients were evaluated before treatment and after 3, 6, and 12 months using Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score, Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee subjective score, Visual Analogue Scale and TEGNER Activity Scores.

RESULTS

All the treatments proved to be effective in reducing pain and improving joint function. The analysis of covariance did not show statistically significant differences among the three groups for any of the investigated outcome parameters after 6 and 12 months (WOMAC: p = 0.45 and p = 0.64, respectively). No significant differences were found in terms of adverse events (p = 0.49) and painkiller use (p = 0.28 and p = 0.56, respectively) among the three groups.

CONCLUSION

This multicenter, prospective, randomized, double-blind controlled trial revealed that intra-articular injections of PRP + HA, PRP, or HA represent a safe and viable treatment with comparable efficacy in terms of pain relief and functional outcomes in mild to moderate knee OA.

Platelet-Rich Plasma Injections Do Not Improve the Recovery After Arthroscopic Partial Meniscectomy: A Double-Blind Randomized Controlled Trial

BACKGROUND

Arthroscopic meniscectomy is one of the most performed surgical procedures in orthopaedics. Different approaches have been proposed to improve patient recovery but with unsatisfactory results. Platelet-rich plasma (PRP) augmentation has been proposed as a strategy to improve the recovery after meniscectomy.

PURPOSE

To investigate the clinical benefits of an intra-articular PRP injection after meniscectomy, in terms of faster and better patient recovery.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Ninety patients were randomized into a treatment group, with arthroscopic partial meniscectomy immediately followed by a 5-mL injection of autologous conditioned plasma, and a control group with partial meniscectomy alone. Patients were evaluated at baseline and at 15, 30, 60, and 180 days of follow-up with the visual analog scale (VAS) score for pain (primary outcome), as well as with International Knee Documentation Committee subjective score, Knee injury and Osteoarthritis Outcome Score subscales, Tegner score, and EuroQol-Visual Analog Scale score. Objective evaluation was performed analyzing knee range of motion and circumference and the International Knee Documentation Committee objective score. Complications, patient judgment, and satisfaction were documented as well.

RESULTS

No major complications and an overall significant improvement in the clinical scores were observed in both groups. Overall, the comparative analysis did not demonstrate significant between-group differences in absolute values or improvements of both subjective and objective scores, as well as activity level. The improvement in terms of VAS pain score for the treatment group was significant already at 15 days (from 4.3 ± 2.5 to 2.5 ± 2.5; P = .014), while in the control group it became significant at 30 days (from 3.7 ± 2.3 to 2.0 ± 2.4; P = .004). No significant differences were observed between the 2 groups in terms of judgment of treatment results and satisfaction.

CONCLUSION

A single postoperative injection of PRP was not able to significantly improve patient recovery after arthroscopic partial meniscectomy. PRP augmentation did not provide overall benefits at a short-term follow-up (6 months) in terms of pain relief, function, objective parameters, and return-to-sport activities.

REGISTRATION

NCT02872753 (ClinicalTrials.gov identifier).

Edge advances in nanodrug therapies for osteoarthritis treatment

As global population and lifestyles change, osteoarthritis (OA) is becoming a major healthcare challenge world. OA, a chronic condition characterized by inflammatory and degeneration, often present with joint pain and can lead to irreversible disability. While there is currently no cure for OA, it is commonly managed using nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and glucosamine. Although these treatments can alleviate symptoms, it is difficult to effectively deliver and sustain therapeutic agents within joints. The emergence of nanotechnology, particularly in form of smart nanomedicine, has introduced innovative therapeutic approaches for OA treatment. Nanotherapeutic strategies offer promising advantages, including more precise targeting of affected areas, prolonged therapeutic effects, enhanced bioavailability, and reduced systemic toxicity compared to traditional treatments. While nanoparticles show potential as a viable delivery system for OA therapies based on encouraging lab-based and clinical trials results, there remails a considerable gap between current research and clinical application. This review highlights recent advances in nanotherapy for OA and explore future pathways to refine and optimize OA treatments strategies.

Beyond Boundaries of a Trial: Post-Market Clinical Follow-Up of SOYA Patients

Background/Objectives: osteoarthritis (OA) is a leading cause of disability. With an aging population and rising obesity rates, OA presents a growing challenge to health systems worldwide. Current OA treatments involve a mix of pharmacological and nonpharmacological interventions. Viscosupplementation with hyaluronic acid (HA) has proven effective, especially in knee OA, leading to its recommendation in international guidelines. This study investigates the sustained benefits of a single intra-articular HA injection beyond one year in patients coming from the SOYA trial, considering the EU MDR 2017/745 emphasis on post-market follow-up. Methods: A prospective, observational, open, post-marketing study in a cohort of patients that participated in the SOYA trial. Follow-up was carried out by means of a telephone survey, and the data were anonymized and coded so that patients could not be identified. The study was approved by the Alcorcón Hospital Institutional Review Board (Alcorcón, Madrid, Spain). Results: In the follow-up of the SOYA trial, 81.5% of patients sustained positive effects for over 6 months after the trial ended. This correlated with improved daily functioning, enhanced mood, and high patient satisfaction. Younger age and milder OA grades were associated with prolonged treatment effects. Notably, 82% of patients with >6 months of improvement did not require additional medication. Conclusions: the results of this study support the safety and performance of Adant® Plus as a treatment for patients with mild and moderate knee OA, with results lasting more than one year. Post-marketing studies are particularly relevant to examine the experience gained with the use of the device in routine clinical practice.

A retrospective claims data analysis of health care utilization and cost among patients receiving multi-injection intraarticular hyaluronic acid

BACKGROUND

With the rising costs for knee arthroplasty, therapies that allow patients to avoid or delay surgery following knee osteoarthritis (KOA) may help in reducing overall health care costs. Multiple intraarticular hyaluronic acid (HA) products are available on the market, varying by formulation, molecular weight, and number of injections, but clinical and economic benefits may differ by product. OBJECTIVES: To evaluate the all-cause and KOA-related health care resource utilization (HCRU) and costs among newly diagnosed patients with KOA treated with multi-injection HA.

METHODS

A retrospective cohort study using a large commercial claims database (Merative MarketScan database) to identify patients with KOA treated with high molecular weight (HMW) (n = 11,200), medium molecular weight (MMW) (n = 10,225), or low molecular weight (LMW) HAs (n = 8,473) between 2016 and 2019. KOA-related and all-cause HCRU and costs were compared within 12 months after the index HA treatment date. The association between outcomes and HA treatments was evaluated using a doubly robust method to adjust for confounding factors. HCRU and costs among the propensity score-weighted HA groups were compared using generalized linear models.

RESULTS

HMW HA patients were found to have lower adjusted KOA-related medical costs by $265.37 (P < 0.001) and pharmacy costs by $19.90 (P < 0.001) compared with LMW HA patients, as well as lower all-cause total medical costs by $130.42 (P = 0.013) and pharmacy costs by $63.33 (P < 0.001). HMW HA patients also had a lower adjusted KOA-related medical cost by $205.74 (P < 0.001) and pharmacy cost by $14.39 (P < 0.001) compared with MMW HA patients, as well as lower all-cause medical by $1,195.66 (P < 0.001) and pharmacy by $196.99 (P < 0.001). Three-injection treatment patients (HMW HA, 84%; MMW HA, 82%) had high completion rate, compared with the 5-injection treatment cohort (LMW HA, 48%).

CONCLUSIONS

HMW HA patients had statistically significantly lower adjusted all-cause and KOA-related medical and pharmacy costs at 1 year follow-up compared with MMW HA and LMW HA patients. It is unclear if this is related to differences in molecular weight or specific mechanism of actions.

Minimally Invasive Therapies for Knee Osteoarthritis

Knee osteoarthritis (KOA) is a musculoskeletal disorder characterized by articular cartilage degeneration and chronic inflammation, affecting one in five people over 40 years old. The purpose of this study was to provide an overview of traditional and novel minimally invasive treatment options and role of artificial intelligence (AI) to streamline the diagnostic process of KOA. This literature review provides insights into the mechanisms of action, efficacy, complications, technical approaches, and recommendations to intra-articular injections (corticosteroids, hyaluronic acid, and plate rich plasma), genicular artery embolization (GAE), and genicular nerve ablation (GNA). Overall, there is mixed evidence to support the efficacy of the intra-articular injections that were covered in this study with varying degrees of supported recommendations through formal medical societies. While GAE and GNA are more novel therapeutic options, preliminary evidence supports their efficacy as a potential minimally invasive therapy for patients with moderate to severe KOA. Furthermore, there is evidentiary support for the use of AI to assist clinicians in the diagnosis and potential selection of treatment options for patients with KOA. In conclusion, there are many exciting advancements within the diagnostic and treatment space of KOA.

Effects of the oral administration of glycosaminoglycans with or without native type II collagen on the articular cartilage transcriptome in an osteoarthritic-induced rabbit model

BACKGROUND

In a previous study, the 84-day administration of glycosaminoglycans (GAGs), with or without native collagen type II (NC), in an osteoarthritis (OA)-induced rabbit model slowed down OA progression, improved several micro- and macroscopic parameters and magnetic resonance imaging (MRI) biomarkers in cartilage, and increased hyaluronic acid levels in synovial fluid. To elucidate the potential underlying mechanisms, a transcriptomics approach was conducted using medial femoral condyle and trochlea samples.

RESULTS

The administration of chondroitin sulfate (CS), glucosamine hydrochloride (GlHCl), and hyaluronic acid (HA), with (CGH-NC) or without (CGH) NC, strongly modulated several genes involved in chondrocyte extracellular matrix (ECM) remodeling and homeostasis when compared to non-treated rabbits (CTR group). Notably, both treatments shared the main mechanism of action, which was related to ECM modulation through the down-regulation of genes encoding proteolytic enzymes, such as ADAM metallopeptidase with thrombospondin type 1 motif, 9 (Adamts9), and the overexpression of genes with a relevant role in the synthesis of ECM components, such as aggrecan (Acan) in both CGH-NC and CGH groups, and fibronectin 1 (Fn1) and collagen type II, alpha 1 (Col2A1) in the CGH group. Furthermore, there was a significant modulation at the gene expression level of the mTOR signaling pathway, which is associated with the regulation of the synthesis of ECM proteolytic enzymes, only in CGH-NC-supplemented rabbits. This modulation could account for the better outcomes concerning the microscopic and macroscopic evaluations reported in these animals.

CONCLUSIONS

In conclusion, the expression of key genes involved in chondrocyte ECM remodeling and homeostasis was significantly modulated in rabbits in response to both CGH and CGH-NC treatments, which would partly explain the mechanisms by which these therapies exert beneficial effects against OA.

Association between intra-articular hyaluronic acid injections in delaying total knee arthroplasty and safety evaluation in primary knee osteoarthritis: analysis based on Health Insurance Review and Assessment Service (HIRA) claim database in Republic of Korea

BACKGROUND

The prevalence of knee osteoarthritis (KOA), a progressive degenerative disease, is gradually increasing, and it is a progressive degenerative disease. In patients with mild-to-moderate KOA, intra-articular hyaluronic acid (IA-HA) has been shown to be an effective non-operative treatment option that can provide significant pain relief and symptom improvement by increasing intra-articular viscoelasticity. This study aimed to evaluate the efficacy of IA-HA injections in delaying total knee arthroplasty (TKA) and the safety of IA-HA according to IA-HA type and combination with intra-articular corticosteroid (IA-CS) using a large health insurance claim database.

METHODS

For this retrospective cohort study, the study population included patients aged ≥ 50 years with a first diagnosis of KOA between 2009 and 2014, who underwent TKA by 2020, using the Health Insurance Review and Assessment Service claim database in Republic of Korea. IA-HA injections were categorized as single or multiple injection regimen agents. Cox proportional hazard models estimated hazard ratios (HR) for TKA risk, adjusted for covariates. Logistic regression assessed the occurrence of adverse events after IA-HA administration.

RESULTS

In all, 36,983 patients were included. Patients who received IA-HA injections had a significantly longer time to TKA compared to those who did not (mean delay of approximately 1 year). The IA-HA group had a significantly lower risk of TKA (HR: 0.61, 95% CI: 0.60-0.62) than non-IA-HA group after adjusting for covariates, which included age, sex, medical history, number of hospital beds, and CS injection. Single injection IA-HA regimen agents showed the longest time to TKA and lowest risk (HR: 0.56, 95% CI: 0.53-0.59). TKA risk decreased with the number of IA-HA cycles. Adverse events occurred in 6.7% of IA-HA cases without CS, with very low incidence of infection. Multiple injection regimen agents (multiple injection regimen 7.0% vs. single injection regimen 3.6%) and concurrent IA-CS use (concurrent IA-CS use 13.9% vs. IA-HA only 6.7%) were associated with higher infection risk.

CONCLUSION

IA-HA injections were associated with a significant delay in TKA among patients with KOA. Single-injection regimen agents had the lowest TKA risk. Infection risk increased with multiple injections and concurrent IA-CS use. These findings could suggest the use of IA-HA as an effective non-operative intervention option for managing KOA and delaying TKA. Careful selection of IA-HA type and consideration of concurrent IA-CS use could play a role in delaying the time to TKA and reducing complications.

Corticosteroid injections for knee osteoarthritis offer clinical benefits similar to hyaluronic acid and lower than platelet-rich plasma: a systematic review and meta-analysis

Purpose

Intra-articular corticosteroid (CS) injections for knee osteoarthritis (OA) management are endorsed by several scientific societies, while the use of hyaluronic acid (HA) and platelet-rich plasma (PRP) is more controversial. Aim of the study was to quantify and compare the clinical effectiveness of CS injections with respect to HA and PRP in patients with knee OA.

Methods

The search was conducted on PubMed, Cochrane, and Web of Science following the PRISMA guidelines. Randomized controlled trials (RCTs) on the comparison of CS injections and HA or PRP injections for the treatment of knee OA were included. The minimal clinically important difference (MCID) was used to interpret the clinical relevance of the improvements at different follow-ups up to 12 months. The study quality was assessed using the Cochrane RoB-2 tool and the GRADE guidelines.

Results

Thirty-five RCTs were included (3348 patients). The meta-analysis comparing CS and HA revealed no difference in terms of WOMAC improvement, while HA showed superior VAS pain improvement at long-term follow-up (P = 0.011), without reaching the MCID. PRP offered a superior WOMAC improvement compared to CS at short- (P = 0.002), mid- (P < 0.001, exceeding the MCID), and long-term (P < 0.001, exceeding the MCID) follow-ups. PRP offered a superior VAS improvement at mid- (P < 0.001, exceeding the MCID) and long-term (P = 0.023) follow-ups.

Conclusion

CS injections for knee OA offer similar results to HA and PRP only at short term, while there is an overall superiority of PRP at longer follow-ups. This difference is not only statistically significant but also clinically relevant in favour of PRP.

Infiltration therapy in the context of cartilage surgery

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

Treatment of anterior knee pain due to chondromalacia patellae with platelet-rich plasma and hyaluronic acid in young and middle-aged adults, a cohort study

INTRODUCTION

Anterior knee pain commonly affects young women resulting in the declination of the quality of life. One of the possible pathologies causing this symptom is chondromalacia patellae (CMP). Although CMP is used to describe the softening of patellar articular cartilage, it remains a general descriptive term as it cannot be associated with a specific pathophysiologic mechanism. The objective of this study is to investigate the effect of injectable PRP on patients with anterior knee pain in absence of altered patellofemoral joint anatomy.

METHODS

For this purpose, 43 patients of the affected population were recruited to participate in this non-randomized controlled trial, 28 patients in the injection group and 15 in the only-physiotherapy group. While patients in the experimental group received three PRP injections and one injection of hyaluronic acid (HA), comparators received the standard physical therapy regimen. The treatment choice was based on patients own decree. Patients between the ages of 18 to 50 years with anterior knee pain and positive Clarke´s sign were eligible for inclusion. Patients with evident anatomical abnormalities, chronic conditions affecting the knee and severe symptoms such as blocking, were excluded from the study. Patient related measures (PROMS) in the form of the VAS and the Kujala scores were the main outcome of interest. All outcomes were measured at baseline, and after 3 and 6 months after the treatment.

RESULTS

Although an improvement was seen in both groups, a statistically significant difference favoring the injection of PRP over the physiotherapy-only group was observed (p < 0.001). The superiority of the therapeutic modality under investigation was observed at 3 and 6 months after the initial diagnosis was made. Furthermore, the results of this study revealed a significant improvement at 3 and 6 months when compared to baseline measures. The analysis of the patients age showed a negative correlation when baseline values were compared to measures at 3 and 6 months, meaning younger patients had more benefit from the treatment.

DISCUSSION

The main results of this study affirm the positive effects of PRP and HA for the treatment of anterior knee pain described by previous research and the subsequent improvement of the quality of life. Relatively little information was found in the literature search regarding the therapeutic effects of PRP on anterior knee pain and chondropathies. While a previous radiologic study found no evidence regarding the effect of PRP, this study found a benefit when comparing PROMs between patient groups.

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.

Coaxial Bioprinting of Enzymatically Crosslinkable Hyaluronic Acid-Tyramine Bioinks for Tissue Regeneration

Three-dimensional (3D) bioprinting has emerged as an important technique for fabricating tissue constructs with precise structural and compositional control. However, developing suitable bioinks with biocompatible crosslinking mechanisms remains a significant challenge. This study investigates extrusion-based bioprinting (EBB) using uniaxial or coaxial nozzles with enzymatic crosslinking (EC) to produce 3D tissue constructs in vitro. Initially, low-molecular-weight dextran-tyramine and hyaluronic acid-tyramine (LMW Dex-TA/HA-TA) bioink prepolymers were evaluated. Enzymatically pre-crosslinking these prepolymers, achieved by the addition of horseradish peroxidase and hydrogen peroxide, produced viscous polymer solutions. However, this approach resulted in inconsistent bioprinting outcomes (uniaxial) due to inhomogeneous crosslinking, leading to irreproducible properties and suboptimal shear recovery behavior of the hydrogel inks. To address these challenges, we explored a one-step coaxial bioprinting system consisting of enzymatically crosslinkable high-molecular-weight hyaluronic acid-tyramine conjugates (HMW HA-TA) mixed with horseradish peroxidase (HRP) in the inner core and a mixture of Pluronic F127 and hydrogen peroxide in the outer shell. This configuration resulted in nearly instantaneous gelation by diffusion of the hydrogen peroxide into the core. Stable hydrogel fibers with desirable properties, including appropriate swelling ratios and controlled degradation rates, were obtained. The optimized bioink and printing parameters included 1.3% w/v HMW HA-TA and 5.5 U/mL HRP (bioink, inner core), and 27.5% w/v Pluronic F127 and 0.1% H2O2 (sacrificial ink, outer shell). Additionally, optimal pressures for the inner core and outer shell were 45 and 80 kPa, combined with a printing speed of 300 mm/min and a bed temperature of 30 °C. The extruded HMW HA-TA core filaments, containing bovine primary chondrocytes (BPCs) or 3T3 fibroblasts (3T3 Fs), exhibited good cell viabilities and were successfully cultured for up to seven days. This study serves as a proof-of-concept for the one-step generation of core filaments using a rapidly gelling bioink with an enzymatic crosslinking mechanism, and a coaxial bioprinter nozzle system. The results demonstrate significant potential for developing designed, printed, and organized 3D tissue fiber constructs.

The Effectiveness of a Single Hyaluronic Acid Injection in Improving Symptoms and Muscular Strength in Patients with Knee Osteoarthritis: A Multicenter, Retrospective Study

Knee osteoarthritis (KOA) is a progressive and multifactorial disease that leads to joint pain, muscle weakness, physical disability, and decreased quality of life. In KOA, the quantity of hyaluronic acid (HA) and the molecular weight (MW) are decreased, leading to joint pain due to increased wear of the knee articular cartilage. Arthrogenic muscle inhibition, which is usually found in patients with KOA, is associated with joint inflammation, pain, and swelling, also causing muscle atrophy, primarily of the anterior thigh muscles, and hindering the rehabilitation process. The aim of our work was to determine if a single HA infiltration could minimize the effects of arthrogenic muscle inhibition in patients with KOA in the short term, using isokinetic dynamometry to evaluate the strength of the knee extensor and flexor muscles of the thigh. Thirty patients with KOA who underwent both clinical and isokinetic assessment, and that received a single injection of HA, were retrospectively included. Our results showed that a single intra-articular injection of HA significantly reduces pain and improves joint function at four weeks, while non-statistically significant improvements were observed for the reference isokinetic parameter (maximum torque) at both 90°/s and 180°/s. Further high-quality studies are necessary to confirm the results of our study.

Advancements in pH-Responsive nanoparticles for osteoarthritis treatment: Opportunities and challenges

Osteoarthritis (OA) is a degenerative disease linked to aging and obesity. The global aging population has led to an increasing number of OA patients, imposing a significant economic burden on society. Traditional drugs treatment methods often fail to achieve satisfactory outcomes. With the rapid advancement of nanomaterial delivery systems, numerous studies have focused on utilizing nanomaterials as carriers to achieve efficient OA treatment by effectively loading and delivering bioactive ingredients (e.g., drugs, nucleic acids) tailored to the unique pathological conditions, such as the weakly acidic microenvironment of synovial fluid in OA patients. This review highlights the latest advancements in the use of pH-responsive nanoparticles for OA treatment, emphasizing the principle of targeted drug delivery leveraging the acidic microenvironment of inflamed joints. It further discusses the composition, synthesis, response mechanism, target selection, application, and recent research findings of nanoparticles, while also addressing the challenges and future directions in this promising field.

Assessment of the Feasibility of Objective Parameters as Primary End Points for Patients Affected by Knee Osteoarthritis: Protocol for a Pilot, Open Noncontrolled Trial (:SMILE:)

BACKGROUND

Osteoarthritis (OA) is a disabling condition that affects more than one-third of people older than 65 years. Currently, 80% of these patients report movement limitations, 20% are unable to perform major activities of daily living, and approximately 11% require personal care. In 2014, the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) recommended, as the first step in the pharmacological treatment of knee osteoarthritis, a background therapy with chronic symptomatic slow-acting osteoarthritic drugs such as glucosamine sulfate, chondroitin sulfate, and hyaluronic acid. The latter has been extensively evaluated in clinical trials as intra-articular and oral administration. Recent reviews have shown that studies on oral hyaluronic acid generally measure symptoms using only subjective parameters, such as visual analog scales or quality of life questionnaires. As a result, objective measures are lacking, and data validity is generally impaired.

OBJECTIVE

The main goal of this pilot study with oral hyaluronic acid is to evaluate the feasibility of using objective tools as outcomes to evaluate improvements in knee mobility. We propose ultrasound and range of motion measurements with a goniometer that could objectively correlate changes in joint mobility with pain reduction, as assessed by the visual analog scale. The secondary objective is to collect data to estimate the time and budget for the main double-blind study randomized trial. These data may be quantitative (such as enrollment rate per month, number of screening failures, and new potential outcomes) and qualitative (such as site logistical issues, patient reluctance to enroll, and interpersonal difficulties for investigators).

METHODS

This open-label pilot and feasibility study is conducted in an orthopedic clinic (Timisoara, Romania). The study includes male and female participants, aged 50-70 years, who have been diagnosed with symptomatic knee OA and have experienced mild joint discomfort for at least 6 months. Eight patients must be enrolled and treated with Syalox 300 Plus (River Pharma) for 8 weeks. It is a dietary supplement containing high-molecular-weight hyaluronic acid, which has already been marketed in several European countries. Assessments are made at the baseline and final visits.

RESULTS

Recruitment and treatment of the 8 patients began on February 15, 2018, and was completed on May 25, 2018. Data analysis was planned to be completed by the end of 2018. The study was funded in February 2019. We expect the results to be published in a peer-reviewed clinical journal in the last quarter of 2024.

CONCLUSIONS

The data from this pilot study will be used to assess the feasibility of a future randomized clinical trial in OA. In particular, the planned outcomes (eg, ultrasound and range of motion), safety, and quantitative and qualitative data must be evaluated to estimate in advance the time and budget required for the future main study. Finally, the pilot study should provide preliminary information on the efficacy of the investigational product.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03421054; https://clinicaltrials.gov/study/NCT03421054.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/13642.

Chondrotoxicity of Intra-Articular Injection Treatment: A Scoping Review

The purpose of this scoping review was to identify possible chondrotoxic effects caused by drugs usually used for intra-articular injections. PubMed, Scopus, Web of Science and Cochrane were searched. Inclusion criteria required randomized controlled trials written in English that evaluate the toxic effect that damages the cartilage. The literature search resulted in 185 unique articles. 133 full-text articles were screened for inclusion, of which 65 were included. Corticosteroids, with the exception of triamcinolone, along with local anaesthetics, potentially excluding ropivacaine and liposomal bupivacaine, and nonsteroidal anti-inflammatory drugs, exhibited insufficient safety profiles to warrant casual use in clinical settings. Hyaluronic acid, on the other hand, appears to demonstrate safety while also mitigating risks associated with concurrent compounds, thereby facilitating therapeutic combinations. Additionally, there remains a paucity of data regarding platelet-rich plasma, necessitating further evaluation of its potential efficacy and safety. Overall, it seems that results are significantly influenced by the dosage and frequency of injections administered, observed in both human and animal studies.

Local injection therapy with hyaluronic acid preparations: in focus of rheumatologists and orthopedic traumatologists

   Hyaluronic acid (HA) is an effective and safe medication for local injection therapy (LIT) widely used in the treatment of osteoarthritis (OA) of large joints. The therapeutic effect of HA is determined both by the replacement of the lubricating function of natural hyaluronate (viscosupplementation), which leads to an improvement in the biomechanical parameters of the joint, and by the biological effects that unfold when interacting with cellular receptors (CD44, RHAMM, etc.), resulting in an anti-inflammatory, anti-nociceptive and anabolic effect of HA. HA therapy has a reliable evidence base. According to a number of clinical studies and meta-analyses, LIT with HA – reduces pain intensity by 28–54 % and improves the function of the affected joint by 9–32 % compared to baseline over a 12-24 week observation period. Repeated administration of HA can delay the need for orthopedic surgery. HA extremely rarely causes serious adverse events and can also be prescribed to patients with concomitant diseases. The use of HA for the treatment of OA is included in Russian and several foreign clinical guidelines (in particular OARSI and ESCEO). A new direction in LIT for OA is therapy with combined (hybrid) HA preparations containing high molecular weight (HMW) and low molecular weight (LMW) fractions. A new HA preparation has appeared in our country, which is a stabilized, highly purified hydrogel containing 80 % HMW HA (molecular weight – 30,000 kDa) with transverse "crosslinking" BDDE (innovative ECHATM technology) and 20 % "uncluttered" linear HA (molecular weight – 1500 kDa). This product is characterized by favorable rheological parameters, which guarantee a long-term improvement in the biomechanics of the affected joint and a rapid onset of biological effects, reduction in pain and inflammation and activation of the synthesis of natural hyaluronate.

[Preliminarily study of arthrocentesis combined with liquid phase concentrated growth factor injection in the treatment of unilateral temporomandibular joint osteoarthritis]

OBJECTIVE

To observe the clinical effect of arthrocentesis combined with liquid phase concentrated growth factor (CGF) injection in the treatment of unilateral temporomandibular joint osteoarthritis (TMJOA), in order to provide a new treatment option for TMJOA patients.

METHODS

In this non-randomized controlled study, patients diagnosed with unilateral TMJOA who visited the center for temporomandibular joint disorder and orofacial pain of Peking University School and Hospital of Stomatology from June 2021 to January 2023 were selected as research objects. The patients were divided into experimental group and control group, which were selected by patients themselves. The experimental group received arthrocentesis combined with liquid phase CGF injection and the control group received arthrocentesis combined with HA injection. Both groups were treated 3 times, once every two weeks. The clinical effect was evaluated by the maximum mouth opening, pain value and the degree of mandibular function limitation 6 months after treatment. The change of condylar bone was evaluated by cone beam CT (CBCT) image fusion technology before and after treatment.

RESULTS

A total of 20 patients were included in the experimental group, including 3 males and 17 females, with an average age of (34.40±8.41) years. A total of 15 patients were included in the control group, including 1 male and 14 females, with an average age of (32.20±12.00) years. There was no statistical difference in general information between the two groups (P > 0.05). There were no statistical differences in the mouth opening, pain value and the degree of jaw function limitation between the two groups before treatment (P > 0.05), and all of them improved 6 months after treatment compared with before treatment (P < 0.05). However, the mouth opening of experimental group was significantly higher than that of control group 6 months after treatment (P < 0.05), and the degree of jaw function limitation was significantly lower than that of control group (P < 0.05). CBCT 2D images showed that the condylar bone of both groups was smoother after treatment than before treatment, and image fusion results showed that 10 patients (50.0%) in the experimental group and 5 patients (33.3%) in the control group had reparative remodeling area of condylar bone, and there was no statistical difference between them (P > 0.05). Except for one CGF patient, the other patients in both groups had some absorption areas of condylar bone.

CONCLUSION

The arthrocentesis combined with liquid phase CGF injection can improve the clinical symptoms and signs of unilateral TMJOA patients in short term, and is better than HA in increasing mouth opening and improving jaw function. CBCT fusion images of both patient groups show some cases of condylar bone reparative remodeling and its relevance to treatment plans still requires further study.

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.