Injection-Based Management of Osteoarthritis of the Knee: A Systematic Review of Guidelines

Microfluidic-engineering Prussian blue hydrogel microspheres for enhanced osteoarthritis antioxidant therapy

Osteoarthritis (OA), a degenerative joint disorder and leading cause of global disabilty, imposes substantial societal and familial burdens. Current antioxidant therapies for OA are hindered by poor targeting and transient efficacy, failing to address the excessive reactive oxygen species (ROS)-driven pathogenesis. Herein, we innovatively integrate Prussian blue (PB) nanozymes with alginate-hyaluronic acid (HA) hydrogel microspheres through microfluidic engineering, creating the injectable AlgHA@PB platform that synergizes dual therapeutic mechanisms: ROS scavenging and oxygen generation via PB nanozymes, and sustained intra-articular retention and mechanical compatibility enabled by the hydrogel microsphere architecture. In vitro studies demonstrated that AlgHA@PB scavenged all of intracellular ROS while continuously releasing oxygen within. In a rat OA model, AlgHA@PB exhibited prolonged joint retention and reduced cartilage degeneration. Critically, the microspheres demonstrated a stable friction coefficient, enabling smooth intra-articular motion without mechanical irritation. This study establishes AlgHA@PB as a multifunctional OA therapeutic platform that integrates antioxidative defense, anti-inflammatory action, and biomechanical compatibility. The microfluidic-engineered design ensures scalable production, aligning with clinical translation requirements.

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.

Use and safety of corticosteroid injections in joints and musculoskeletal soft tissue: guidelines from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, the American Society of Interventional Pain Physicians, and the International Pain and Spine Intervention Society

BACKGROUND

Intra-articular corticosteroid (IACS) injection and peri-articular corticosteroid injection are commonly used to treat musculoskeletal conditions. Results vary by musculoskeletal region, but most studies report short-term benefit with mixed results on long-term relief. Publications showed adverse events from single corticosteroid injections. Recommended effective doses were lower than those currently used by clinicians.

METHODS

Development of the practice guideline for joint injections was approved by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine and the participating societies. A Corticosteroid Safety Work Group coordinated the development of three guidelines: peripheral nerve blocks and trigger points; joints; and neuraxial, facet, and sacroiliac joint injections. The topics included safety of the technique in relation to landmark-guided, ultrasound-guided, or radiology-aided injections; effect of the addition of the corticosteroid on the efficacy of the injectate; and adverse events related to the injection. Experts on the topics were assigned to extensively review the literature and initially develop consensus statements and recommendations. A modified version of the US Preventive Services Task Force grading of evidence and strength of recommendation was followed. A modified Delphi process was adhered to in arriving at a consensus.

RESULTS

This guideline focuses on the safety and efficacy of corticosteroid joint injections for managing joint chronic pain in adults. The joints that were addressed included the shoulder, elbow, hand, wrist, hip, knee, and small joints of the hands and feet. All the statements and recommendations were approved by all participants and the Board of Directors of the participating societies after four rounds of discussion. There is little evidence to guide the selection of one corticosteroid over another. Ultrasound guidance increases the accuracy of injections and reduces procedural pain. A dose of 20 mg triamcinolone is as effective as 40 mg for both shoulder IACS and subacromial subdeltoid bursa corticosteroid injections. The commonly used dose for hip IACS is 40 mg triamcinolone or methylprednisolone. Triamcinolone 40 mg is as effective as 80 mg for knee IACS. Overall, IACS injections result in short-term pain relief from a few weeks to a few months. The adverse events include an increase in blood glucose, adrenal suppression, detrimental effect on cartilage lining the joint, reduction of bone mineral density, and postoperative joint infection.

CONCLUSIONS

In this practice guideline, we provided specific recommendations on the role of corticosteroids in joint, bursa, and peritendon injections for musculoskeletal pain.

The Role of Thrombospondins in Osteoarthritis: from Molecular Mechanisms to Therapeutic Potential

Osteoarthritis (OA) is a prevalent chronic degenerative joint disorder characterized by cartilage degeneration, joint inflammation, and pain. The pathogenesis of OA still remains unclear. Among the various factors contributing to OA, the role of extracellular matrix (ECM) proteins, particularly thrombospondins (TSPs), has garnered significant attention. TSPs, a family of multifunctional extracellular matrix glycoproteins, are known to participate in numerous physiological and pathological processes, including cell adhesion, migration, differentiation, angiogenesis, and synaptogenesis through cell-cell and cell-matrix interactions. In this review, we provide a summary of the current understanding of TSP proteins in the pathogenesis of OA, including their effects on cartilage homeostasis, synovial inflammation, and subchondral bone remodeling and arthritic pain. We also review the evidence supporting the potential of TSP proteins as diagnostic biomarkers and therapeutic targets, with a focus on recent advances in cartilage regeneration, gene delivery therapy and pain management. Considering the multifaceted roles of TSP proteins in maintaining articular homeostasis, TSP proteins emerge as promising therapeutic targets for 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 a single dose of cryopreserved human umbilical cord mesenchymal stromal cells for the treatment of knee osteoarthritis:a randomized, controlled, double-blind pilot study

BACKGROUND

Knee osteoarthritis (OA) is the most prevalent degenerative musculoskeletal disorder, which is particularly common in older population. While conventional treatments have limited effectiveness, the development of more effective therapeutic strategies is necessary to address this primary source of pain and disability. Umbilical cord mesenchymal stromal cells (UC-MSCs) offer a promising therapeutic approach for treating knee OA.

AIM

This randomized, prospective, double-blind and controlled pilot study was carried out to evaluate and compare the safety and therapeutic efficacy of a single intra-articular injection of a standardized product CellistemOA (5 × 106 ± 5 × 105 UC-MSCs), vs. triamcinolone (a synthetic corticosteroid) (10 mg/mL) in thirty patients with symptomatic knee OA (Kellgren-Lawrence grade II or III).

METHODS

The outcomes included changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores based on a Likert scale, numerical rating score (NRS) for pain, Magnetic Resonance Imaging (MRI), and quality of life (SF-36 questionnaire), from baseline and throughout 12-months of follow-up.

RESULTS

Patients treated with CellistemOA showed significant improvement in WOMAC score (including the three subscale scores (pain, stiffness and function), NRS in pain, and SF-36 profile from baseline to 12 months (p < 0.05) compared to the triamcinolone group, and no severe adverse events were reported. There were no significant differences in MRI WORMS scores between the two groups. However, patients who received the cellular treatment experienced a significant improvement in their SF-36 profile (p < 0.05).

CONCLUSIONS

This pilot study revealed that a single dose of CellistemOA is safe and superior to the active comparator in knee OA at 1-year of follow-up, making it a compelling therapeutic alternative to treat symptomatic OA patients.

Improved Pain and Function With Triamcinolone Acetonide Extended-Release and Cryoneurolysis for Knee Osteoarthritis: Use of a New Real-World Registry

BACKGROUND

Knee osteoarthritis (OA) affects 19% of American adults aged more than 45 years and costs $27+ billion annually. A wide range of nonoperative treatment options are available. This study compared 6 treatments: cryoneurolysis with deep genicular nerve block (Cryo-Deep/Both), cryoneurolysis with superficial nerve block (Cryo-Superficial), intra-articular hyaluronic acid (IA-HA) injections, nonsteroidal anti-inflammatory drug injections (IA-NSAIDs), IA-corticosteroids (IA-CS) injections, or IA-triamcinolone extended release (IA-TA-ER) injections over 4 months for: (1) pain severity and analgesic use; and (2) physical function (from Knee Injury and Osteoarthritis Outcome Score for Joint Replacement).

METHODS

Patients who had unilateral knee OA and received nonoperative intervention were enrolled in the Innovations in Genicular Outcomes Research registry, a novel, multicenter real-world registry, between September 2021 and February 2024. A total of 480 patients were enrolled. Both pain and functional outcomes were assessed at baseline, weekly, and monthly, which were analyzed by overall trend, magnitude changes pretreatment to post-treatment, and distribution-based minimally clinically important difference (MCID) score. Multivariate linear regressions with adjustments for 7 confounding factors were used to compare follow-up outcomes among 6 treatment groups.

RESULTS

Use of IA-TA-ER injections was associated with the lowest pain, greatest pain reduction, and highest prevalence of patients achieving MCID relative to other treatments (P < .001). Deep/Both-Cryo and IA-CS were associated with a higher prevalence of achieving MCID than IA-HA, IA-NSAIDs, and Cryo-Superficial (P ≤ .001). Use of IA-TA-ER was also associated with the greatest functional score, improvement from baseline, and highest prevalence of patients achieving MCID than other treatments (P ≤ .003).

CONCLUSIONS

The IA-TA-ER appears to outperform other treatments in terms of pain relief and functional improvement for up to 4 months following treatment. In addition, outcomes in the novel cryoneurolysis and conventional IA-CS were similar to one another and better than those in IA-HA and IA-NSAIDs.

Cryoneurolysis Associated With Improved Pain, Function, and Sleep in Patients Following total Knee Arthroplasty: Use of a New Real-World Registry

BACKGROUND

Total knee arthroplasty (TKA) is performed on approximately 790,000 patients annually in the United States and is projected to increase to 1.5 million by 2050. This study aimed at assessing the use of preoperative cryoneurolysis on patients undergoing TKA by analyzing: (1) pain severity; (2) opioid use; (3) functional status; and (4) sleep disturbance (SD) over 6 months following discharge.

METHODS

Patients enrolled in the Innovations in Genicular Outcomes Registry between September 2021 and February 2024 were followed for 6 months. Our analyses included patients undergoing unilateral primary TKA with no preoperative opioid prescription, who either received cryoneurolysis, or did not. Baseline patient demographics were collected before TKA and tabulated. Pain management was assessed via the Brief Pain Inventory-Short Form instrument for pain severity. SD was measured using the patient-reported outcomes measurement information system questionnaire. Each outcome measure was assessed prior to TKA, weekly, and at monthly follow-up. Data were analyzed by a generalized linear mixed-effect regression model to compare cryoneurolysis versus control patients, with a P < .05 as significant.

RESULTS

There were 80 patients who were treated with preoperative cryoneurolysis, while 60 control patients did not have treatment. Patients receiving cryoneurolysis experienced significantly lower pain severity and SD over the 6-month follow-up than control patients (P = .046). Cryoneurolysis was also associated with a trend toward greater functional improvement that did not reach statistical significance (P = .061). Further, patients who underwent cryoneurolysis were 72% less likely than control group patients to take opioids over 6 months following discharge (P < .001).

CONCLUSIONS

Preoperative cryoneurolysis therapy in opioid-naive patients undergoing TKA is associated with improved pain, decreased opioid use, and improved SD for 6 months postoperatively. Cryoneurolysis, a nonopioid pain relief modality administered preoperatively, demonstrated substantial benefits in patients who underwent TKA.

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.

Interventional Radiology for Rheumatic Diseases

Imaging plays a key role in the management of rheumatological pathologies, also as guidance for diagnostic and therapeutic interventional procedures, as it can provide better accuracy and safety compared to palpation-guided interventions. Inflammatory and degenerative conditions nonresponsive to systemic treatment may benefit from intra-articular and periarticular administration of drugs, with therapeutic and symptomatic actions or providing a bridge for surgery. Desired effects include reduction of inflammation and pain and improvement of physical function of patients. Training and knowledge of indications, appropriate procedures, contraindications, and side effects are necessary to obtain maximum accuracy and safety in performing interventional procedures.

Comparison of functional performance outcomes between oral patented crystalline glucosamine sulfate and platelet-rich plasma among knee osteoarthritis patients: a propensity score matching analysis

BACKGROUND

Among the medications used to treat knee osteoarthritis (OA), oral patented crystalline glucosamine sulfate (pCGS) and platelet-rich plasma (PRP) have become popular alternatives to painkillers or nonsteroidal anti-inflammatory drugs (NSAIDs). Although studies have shown that pCGS and PRP improve clinical outcomes, no study has compared outcomes between these optional treatments. We compared functional performance outcomes from baseline to the 1-year follow-up (FU) between oral pCGS and PRP in patients with knee OA.

MATERIALS AND METHODS

Three hundred eighty-two patients receiving oral pCGS and 122 patients receiving PRP injections were enrolled for a review of functional performance outcomes, including a five-time sit-to-stand test (5xSST), time up-and-go test (TUGT), and 3-minute walk distance test (3MWDT). The patients were followed up for one year. The pCGS group received 1500 mg daily, whereas the PRP group received 2 cycles of intra-articular injections at week 0 and week 6. Using propensity score matching based on age, sex, height, weight, BMI, and Kellgren and Lawrence (KL) classification, all three functional performance outcomes were compared between the baseline (pretreatment), 6-week, 12-week, 24-week, and 1-year FUs.

RESULTS

With a ratio of 2:1 (pCGS: PRP), 204 patients in the pCGS group were matched with 102 patients in the PRP group. Compared with the baseline levels, the PRP group showed significant improvements in 5xSST and TUGT outcomes from 6 weeks and significant improvements in 3MWDT outcomes from 12 weeks, whereas the pCGS group showed significant improvements in TUGT outcomes from 6 weeks and significant improvements in 5xSST and 3MWDT outcomes from 12 weeks. At the 24-week and 1-year FU, both groups showed significant improvements in all three functional performance tests without adverse events.

CONCLUSIONS

Although the PRP group showed faster improvements in 5xSST outcomes at six weeks, from the 12-week to 1-year FU, both the pCGS and PRP groups showed significant improvements in 5xSST, TUGT, and 3MWDT outcomes. As the use of PRP is more complicated and invasive than the use of oral pCGS, the benefits and drawbacks of selecting PRP over pCGS in knee OA treatment should be examined.

Development and functional evaluation of a hyaluronic acid coated nano-formulation with kaempferol as a novel intra-articular agent for Knee Osteoarthritis treatment

Knee osteoarthritis (OA) involves articular cartilage degradation driven mainly by inflammation. Kaempferol (KM), known for its anti-inflammatory property, holds potential for OA treatment. This study investigated the potential of hyaluronic acid (HA)-coated gelatin nanoparticles loaded with KM (HA-KM GNP) for treating knee OA. KM was encapsulated into gelatin nanoparticles (KM GNP) and then coated with HA to form HA-KM GNPs. Physical properties were characterized, and biocompatibility and cellular uptake were assessed in rat chondrocytes. Anti-inflammatory and chondrogenic properties were evaluated using IL-1β-stimulated rat chondrocytes, compared with HA-coated nanoparticles without KM (HA GNP) and KM alone. Preclinical efficacy was tested in an anterior cruciate ligament transection (ACLT)-induced knee OA rat model treated with intra-articular injection of HA-KM GNP. Results show spherical HA-KM GNPs (88.62 ± 3.90 nm) with positive surface charge. Encapsulation efficiency was 98.34 % with a sustained release rate of 18 % over 48 h. Non-toxic KM concentration was 2.5 μg/mL. In IL-1β-stimulated OA rat chondrocytes, HA-KM GNP significantly down-regulated RNA expression of IL-1β, TNF-α, COX-2, MMP-9, and MMP-13, while up-regulating SOX9 compared to HA GNP, and KM. In vivo imaging demonstrated significantly higher fluorescence intensity within rat knee joints for 3 hours post HA-KM GNP injection compared with KM GNP (185.2% ± 34.1% vs. 45.0% ± 16.7%). HA-KM GNP demonstrated significant effectiveness in reducing subchondral sclerosis, attenuating inflammation, inhibiting matrix degradation, restoring cartilage thickness, and reducing the severity of OA in the ACLT rat model. In conclusion, HA-KM GNP holds promise for knee OA therapy.

Osteoarthritis: Insights into Diagnosis, Pathophysiology, Therapeutic Avenues, and the Potential of Natural Extracts

Osteoarthritis (OA) stands as a prevalent and progressively debilitating clinical condition globally, impacting joint structures and leading to their gradual deterioration through inflammatory mechanisms. While both non-modifiable and modifiable factors contribute to its onset, numerous aspects of OA pathophysiology remain elusive despite considerable research strides. Presently, diagnosis heavily relies on clinician expertise and meticulous differential diagnosis to exclude other joint-affecting conditions. Therapeutic approaches for OA predominantly focus on patient education for self-management alongside tailored exercise regimens, often complemented by various pharmacological interventions primarily targeting pain alleviation. However, pharmacological treatments typically exhibit short-term efficacy and local and/or systemic side effects, with prosthetic surgery being the ultimate resolution in severe cases. Thus, exploring the potential integration or substitution of conventional drug therapies with natural compounds and extracts emerges as a promising frontier in enhancing OA management. These alternatives offer improved safety profiles and possess the potential to target specific dysregulated pathways implicated in OA pathogenesis, thereby presenting a holistic approach to address the condition's complexities.

Intraarticular botulinum toxin type A versus corticosteroid or hyaluronic acid for painful knee osteoarthritis: A meta-analysis of head-to-head randomized controlled trials

Intraarticular botulinum toxin type A (BTA) has been shown to be effective for painful knee osteoarthritis (KOA), while the efficacy and safety of intraarticular BTA compared to corticosteroid and hyaluronic acid (HA) remains unknown. A meta-analysis was performed to compare. A search was conducted in Medline (PubMed), CENTER (Cochrane Library), Embase (Ovid), Web of Science, Wanfang, and CNKI to find head-to-head randomized controlled trials (RCTs) directly compare the efficacy and safety between intraarticular BTA and intraarticular corticosteroid or HA for patients with painful KOA. The Cochrane Q test and estimation of I2 were used to assess heterogeneity among studies. After incorporating heterogeneity, a random-effects model was employed for data pooling. Overall, six RCTs involving 348 adults with KOA were included. Intraarticular BTA showed similar efficacy with corticosteroid as evidenced by the changes of pain visual analog scale (VAS: -0.35 [-0.97, 0.28]), total Western Ontario McMaster Universities Arthritis Index (WOMAC: 0.28 [-4.13, 4.69]), and WOMAC for pain (0.64 [-0.42, 1.70]), stiffness (-0.02 [-0.54, 0.50]), and function (0.00 [-2.99, 3.00]). Intraarticular BTA was shown to be more effective than HA in improving pain VAS (-1.31 [-1.97, -0.64]) and WOMAC for pain (-4.81 [-8.73, -0.89]), while the influence on WOMAC for knee stiffness (-1.01 [-4.43, 2.41]) and knee function (-1.86 [-6.71, 2.99]) were similar between groups. No serious adverse events were reported. Evidence from pilot RCTs suggests that intraarticular BTA may confer similar efficacy to corticosteroid for KOA, while BTA may be superior to HA for improving knee pain.

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.

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.

Oriental medicine as collaborating treatments with conventional treatments for knee osteoarthritis: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

We aimed to evaluate the effectiveness and safety of oriental medicine (OM) treatments as monotherapy and add-on therapy compared to conventional treatments for knee osteoarthritis and assess the quality of evidence for these results. OM treatment included acupuncture, herbal medicine, pharmacoacupuncture, and moxibustion.

METHODS

PubMed, Embase, Cochrane, Google Scholar, 4 Korean medical databases (KoreaMed, Korean Studies Information Service System, Research Information Service System, and Oriental Medicine Advanced Searching Integrated System), and one Chinese database (China National Knowledge Infrastructure) were searched for articles published between January 1, 2000, and January 1, 2021. Randomized controlled trials (RCTs) investigating the effect of OM interventions, single or combined with conventional treatments, on knee osteoarthritis were searched. The risk of bias and quality of evidence of the included studies were evaluated using the Cochrane Collaboration's risk of bias tool and Grading of Recommendations, Assessment, Development, and Evaluation methods, respectively.

RESULTS

A total of 3911 relevant studies were retrieved and only 23 studies were included for systematic review. Most of the studies showed a significant effect on knee osteoarthritis. 21 studies comparing single OM treatment with conventional treatment were included in the meta-analysis. The effect size of standardized mean difference (SMD) was analyzed as a "small effect" with 0.48 (95% CI -0.80 to -0.16, Z = 2.98, P = .003). In addition, a meta-analysis of 4 studies comparing integrative treatment with conventional treatment showed a "very large effect" with 1.52 (95% CI -2.09 to -0.95, Z = 5.19, P < .001).

CONCLUSION

Our results suggest that single OM treatment and integrative treatment significantly reduce pain in patients with knee osteoarthritis. However, there is a limited number of RCTs considering integrative treatment which implies more related RCTs should be conducted in the future.

Stromal Vascular Fraction in Osteoarthritis of the Knee

In the United States, osteoarthritis (OA) affects 30 million people among the population and poses a major disability and financial burden that impact functional quality of life among the affected individuals [...].

Mechanisms of analgesic effect of mesenchymal stem cells in osteoarthritis pain

Osteoarthritis (OA) is the most common musculoskeletal disease, and it is a major cause of pain, disability and health burden. Pain is the most common and bothersome presentation of OA, but its treatment is still suboptimal, due to the short-term action of employed analgesics and their poor adverse effect profile. Due to their regenerative and anti-inflammatory properties, mesenchymal stem cells (MSCs) have been extensively investigated as a potential therapy for OA, and numerous preclinical and clinical studies found a significant improvement in joint pathology and function, pain scores and/or quality of life after administration of MSCs. Only a limited number of studies, however, addressed pain control as the primary end-point or investigated the potential mechanisms of analgesia induced by MSCs. In this paper, we review the evidence reported in literature that support the analgesic action of MSCs in OA, and we summarize the potential mechanisms of these antinociceptive effects.

3D-Cultured Adipose-Derived Stem Cell Spheres Using Calcium-Alginate Scaffolds for Osteoarthritis Treatment in a Mono-Iodoacetate-Induced Rat Model

Osteoarthritis (OA) is a degenerative disease that causes pain, cartilage deformation, and joint inflammation. Mesenchymal stem cells (MSCs) are potential therapeutic agents for OA treatment. However, the 2D culture of MSCs could potentially affect their characteristics and functionality. In this study, calcium-alginate (Ca-Ag) scaffolds were prepared for human adipose-derived stem cell (hADSC) proliferation with a homemade functionally closed process bioreactor system; the feasibility of cultured hADSC spheres in heterologous stem cell therapy for OA treatment was then evaluated. hADSC spheres were collected from Ca-Ag scaffolds by removing calcium ions via ethylenediaminetetraacetic acid (EDTA) chelation. In this study, 2D-cultured individual hADSCs or hADSC spheres were evaluated for treatment efficacy in a monosodium iodoacetate (MIA)-induced OA rat model. The results of gait analysis and histological sectioning showed that hADSC spheres were more effective at relieving arthritis degeneration. The results of serological and blood element analyses of hADSC-treated rats indicated that the hADSC spheres were a safe treatment in vivo. This study demonstrates that hADSC spheres are a promising treatment for OA and can be applied to other stem cell therapies or regenerative medical treatments.

The Role of Ferroptosis in the Pathogenesis of Osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis. Its high prevalence, especially in the elderly, and its negative impact on physical function make it a leading cause of disability in the elderly. Joint pain as well joint stiffness are the common classic signs of OA. Chondrocyte death together with loss of articular cartilage integrity are the main pathologic changes in OA. Non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids are commonly used for the management of OA; still, their effectiveness is limited, and no therapeutic strategy is able to fully stop OA progression. Ferroptosis is a kind of cell death, distinct from apoptosis and necroptosis, caused by iron-dependent peroxidation of membrane phospholipids that terminates cell life by disintegrating all plasma membranes. It has been suggested that ferroptosis has a critical role in decreased viability of chondrocytes in OA, and here, we review recent findings regarding the pathologic pathways that lead to chondrocyte ferroptosis, and discuss the possible therapeutic utility of ferroptosis inhibition in OA.

Different molecular weights of hyaluronan research in knee osteoarthritis: A state-of-the-art review

Osteoarthritis (OA), the most common form of arthritis, is characterized by progressive cartilage destruction, concomitant adaptive osteogenesis, and loss of joint function. The progression of OA with aging is associated with a decrease in native hyaluronan (HA, hyaluronate or hyaluronic acid) with a high molecular weight (HMW) in synovial fluid and a subsequent increase in lower MW HA and fragments. As HMW HA possesses numerous biochemical and biological properties, we review new molecular insights into the potential of HA to modify OA processes. Different MWs in the formulation of products appear to have varying effects on knee OA (KOA) pain relief, improved function, and postponing surgery. In addition to the safety profile, more evidence indicates that intraarticular (IA) HA administration may be an effective option to treat KOA, with a particular emphasis on the use of HA with fewer injections of higher MW, including potential applications of HA of very HMW. We also analyzed published systemic reviews and meta-analyses of IA HA in treating KOA in order to discuss their conclusions and consensus statements. According to its MW, HA may offer a simple way to refine therapeutic information in selective KOA.

Multiple Injections of Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Current Evidence in Randomized Controlled Trials

In recent years, various clinical trials have focused on treating knee osteoarthritis (KOA) with multiple injections of platelet-rich plasma (PRP). However, compared with the multiple hyaluronic acid (m-HA) injections, the clinical efficacy of multiple PRP (m-PRP) injections for KOA still remains controversial among these studies. Therefore, we aimed to compare the clinical effectiveness of m-PRP injections with m-HA injections in the treatment of KOA in this systematic review. Relevant clinical trials were searched via bibliographic databases, including Medline, PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials, to compare the m-PRP and m-HA injections in the treatment of KOA. Finally, fourteen randomized controlled trials, including 1512 patients, showed the postoperative VAS, WOMAC, IKDC, or EQ-VAS scores and were enrolled in this systematic review. Compared with the group of intra-articular m-HA injections, the group of intra-articular m-PRP injections was lower in the VAS scores at 3-month (WMD = −0.25; 95%CI, −0.40 to −0.10, p = 0.0009) and 12-month (WMD = −0.64; 95%CI, −0.79 to −0.49, p < 0.00001) follow-ups. In addition, the group of intra-articular m-PRP injections was also lower in the WOMAC scores at 1-month (WMD = −1.23; 95%CI, −2.17 to −0.29, p = 0.01), 3-month (WMD = −5.34; 95%CI, −10.41 to −0.27, p = 0.04), 6-month (WMD = −11.02; 95%CI, −18.09 to −3.95, p = 0.002), and 12-month (WMD = −7.69; 95%CI, −12.86 to −2.52, p = 0.004) follow-ups. Furthermore, compared with the group of intra-articular m-HA injections, the group of intra-articular m-PRP injections was higher in the IKDC scores at 3-month (WMD = 7.45; 95%CI, 2.50 to 12.40, p = 0.003) and 6-month (WMD = 5.06; 95%CI, 1.94 to 8.18, p = 0.001) follow-ups. However, the long-term adverse side of m-PRP injections for KOA still needs more large-scale trials and long-term follow-ups.

Efficacy and safety of GLucocorticoid injections into InfrapaTellar faT pad in patients with knee ostEoarthRitiS: protocol for the GLITTERS randomized controlled trial

BACKGROUND

Knee osteoarthritis (OA) is a prevalent disabling disorder that involves changes in articular cartilage damage, subchondral bone remodeling, synovitis, and abnormal infrapatellar fat pad (IPFP). Due to the complicated etiology and numerous phenotypes of knee OA, limited improvement is achieved for treatments among knee OA patients with different phenotypes. Inflammatory OA phenotype is a typical knee OA phenotype, and individualized treatment targeting inflammation is a promising way to obtain an optimal therapeutic effect for people with inflammatory knee OA phenotype. Glucocorticoid is a traditional anti-inflammatory drug for knee OA, and intra-articular glucocorticoid injections are recommended clinically. However, emerging evidence has shown that repeated intra-articular glucocorticoid injections in the long term would induce cartilage loss. IPFP and its adjacent synovium are considered as the main source of inflammation in knee OA. This GLITTERS trial aims to investigate if a glucocorticoid injection into the IPFP is effective and safe over 12 weeks among knee OA patients with an inflammatory phenotype.

METHODS

GLITTERS is a multicenter, double-blinded, randomized, and placebo-controlled clinical trial among knee OA patients with both Hoffa-synovitis and effusion-synovitis. Sixty participants will be allocated randomly and equally to either the glucocorticoid group or the control group. Each group will receive an injection of glucocorticoid or saline into the IPFP with an intra-articular hyaluronic acid injection as a background treatment at baseline and be followed at 4, 8, and 12 weeks. The primary outcomes will be changes in knee pain on a visual analog scale and effusion-synovitis volume measured on magnetic resonance imaging (MRI). The secondary outcomes will be changes in the total score of Western Ontario and McMaster Universities Osteoarthritis Index score, MRI-detected Hoffa-synovitis score, quality of life, pain medication use, IPFP volume, and the incidence of adverse reactions. Data analyses based on the intention-to-treat principle will include mixed-effects regressions, Wilcoxon rank-sum tests, and chi-square tests (or Fisher's exact test).

DISCUSSION

GLITTERS may provide high-quality evidence for the efficacy and safety of ultrasound-guided glucocorticoid injections into IPFP among people with inflammatory knee OA in a short term. The results of this trial are expected to provide a reliable reference for a longer-term risk-benefit profile of this treatment in the future.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05291650. Registered on 23 March 2022.

Biologic Therapies for the Treatment of Knee Osteoarthritis: An Updated Systematic Review

BACKGROUND

Use of "orthobiologics" continues to expand for patients who have knee osteoarthritis (OA). We sought to perform a systemic review of biologic therapies relative to comparative groups, including the following: (1) platelet-rich plasma (PRP); (2) bone marrow-derived mesenchymal stem cells (BMSCs); (3) adipose-derived mesenchymal stem cells (ADSCs); and (4) amniotic-derived mesenchymal stem cells (AMSCs). We assessed the following: (1) study methodologies; (2) cell preparations and formulations; (3) patient-reported outcome scores (PROMs); and (4) structural changes.

METHODS

PubMed, Cochrane Library, and Embase databases were queried (2013-2021) to conduct a systematic review of biologic therapies for knee OA, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eighty-two studies were included: PRP (51); BMSC (15); ADSC (11); and AMSC (5). Study evaluations were made using the Modified Coleman Methodology Score. PROMs included the Western Ontario and McMaster Universities Arthritis Index and the Visual Analog Scale. Structural change evaluations included ultrasounds, radiographs, or magnetic resonance imaging.

RESULTS

PRP comprised a majority of the studies (n = 51), most with "fair" to "good" Modified Coleman Methodology Score. Studies had variable cell preparations and formulations, with comparison study results leading to inconsistent PROMs, and structural changes. A limited number of studies were included for BMSC, ADSC, and AMSC, all with similar findings to PRP.

CONCLUSION

Available literature evaluating "orthobiologics" for knee OA remain nonsuperior to comparison cohorts. Higher level studies with larger sample sizes and improved methodologies are warranted to suggest differences. Despite a growth of "orthobiologics" in clinics, this updated systematic review highlights the uncertain efficacy for use in knee OA.

Collagen type II-hyaluronan interactions - the effect of proline hydroxylation: a molecular dynamics study

Hyaluronan-collagen composites have been employed in numerous biomedical applications. Understanding the interactions between hyaluronan and collagen is particularly important in the context of joint cartilage function and the treatment of joint diseases. Many factors affect the affinity of collagen for hyaluronan. One of the important factors is the ratio of 3- or 4-hydroxy proline to proline residues. This article presents the results from molecular dynamics calculations of HA-collagen type II interactions with hyaluronan. The applied protocol employed docking and geometry optimization of complexes built using collagen structures with different numbers of hydroxyl groups attached to proline moieties. It was established that the hydroxyproline/proline ratio affects both structural and energetic features of the collagen-hyaluronan complex. Proline hydroxylation was found to significantly influence the number of all identified types of molecular forces, hydrophobic interactions, water bridges and hydrogen bonds, which can be formed between collagen and hyaluronan. Importantly, an increase in the hydroxyproline/proline ratio in the collagen chain increases the binding affinity for hyaluronan. This is illustrated by the linear correlation between the binding free energy and the hydroxylation degree. A comparison of the results obtained for 3 and 4 hydroxylation of proline indicates that the hydroxyl group attachment position plays a minor role in complex stabilization. However, a slightly stronger affinity was observed for 4 hydroxylation. In order to evaluate the effect of the aqueous environment on the collagen-hyaluronan complex stability, the enthalpic and entropic contributions to the free energy of solvation were analyzed.

Autologous Stem Cells Transplants in the Treatment of Temporomandibular Joints Disorders: A Systematic Review and Meta-Analysis of Clinical Trials

This systematic review aims to analyze the outcomes of the treatment of temporomandibular joint (TMJ) articular pain (AP) and restricted maximum mouth opening (MMO) with intra-articular administration of mesenchymal stem cells (MSCs). The inclusion criteria allowed primary studies involving AP and/or MMO pre-treatment and post-intervention values. Medical databases that were covered by ACM Digital, BASE, EBSCOhost, Google Scholar, PubMed, Scopus, and Web of Science engines were searched. The risk of bias was assessed with RoB 2 and ROBINS-I tools. The results were tabulated, plotted, and analyzed for regression. A total of 5 studies involving 51 patients/69 TMJs were identified, and 4 studies on 50 patients/67 TMJs were synthesized. Interventions were each time effective in decreasing AP and increasing MMO in a 6-month follow-up period by an average of about 85% and over 40%, respectively. Regression analysis showed a good fit of the logarithmic model for AP relief (5.8 − 0.8 ln x; R² = 0.90) and MMO increase (33.5 + 2.4 ln x; R² = 0.89). The results for AP and MMO were based on 3 studies in 39 patients and 4 studies in 50 patients, respectively, all at high risk of bias. The intra-articular administration of MSCs to TMJs, based on weak evidence, may be highly effective in reducing AP and improving MMO. This study received no funding.

Functionalized Nanogels with Endothelin-1 and Bradykinin Receptor Antagonist Peptides Decrease Inflammatory and Cartilage Degradation Markers of Osteoarthritis in a Horse Organoid Model of Cartilage

Osteoarthritis (OA) is a degenerative and heterogeneous disease that affects all types of joint structures. Current clinical treatments are only symptomatic and do not manage the degenerative process in animals or humans. One of the new orthobiological treatment strategies being developed to treat OA is the use of drug delivery systems (DDS) to release bioactive molecules over a long period of time directly into the joint to limit inflammation, control pain, and reduce cartilage degradation. Two vasoactive peptides, endothelin-1 and bradykinin, play important roles in OA pathogenesis. In this study, we investigated the effects of two functionalized nanogels as DDS. We assessed the effect of chitosan functionalized with a type A endothelin receptor antagonist (BQ-123-CHI) and/or hyaluronic acid functionalized with a type B1 bradykinin receptor antagonist (R-954-HA). The biocompatibility of these nanogels, alone or in combination, was first validated on equine articular chondrocytes cultured under different oxic conditions. Further, in an OA equine organoid model via induction with interleukin-1 beta (IL-1β), a combination of BQ-123-CHI and R-954-HA (BR5) triggered the greatest decrease in inflammatory and catabolic markers. In basal and OA conditions, BQ-123-CHI alone or in equimolar combinations with R-954-HA had weak pro-anabolic effects on collagens synthesis. These new nanogels, as part of a composite DDS, show promising attributes for treating OA.

Hyaluronic Acid Injections for Knee Osteoarthritis: Has Utilization Among Medicare Beneficiaries Changed Between 2012 and 2018?

BACKGROUND

The utilization of hyaluronic acid (HA) for the management of knee osteoarthritis (OA) remains controversial, and more information is needed regarding how its utilization and financial burden have changed over recent years. The purpose of our analysis was to evaluate changes in overall utilization and health-care costs associated with HA injections among Medicare beneficiaries over a contemporary time frame.

METHODS

The 2012 to 2018 Medicare Fee-for-Service Provider Utilization and Payment Public Use Files (PUFs) were utilized for our analysis. Organized by Healthcare Common Procedure Coding System (HCPCS) codes, these files capture 100% of Medicare Part B claims. Payment and utilization data were collected for all HCPCS codes corresponding to injection of an HA formulation. The number of services involving HA as well as the total cost of HA administration in 2020 U.S. dollars were tabulated. Mann-Kendall trend tests were used to evaluate trends in utilization for providers nationally and when segregated by specialty.

RESULTS

Total HA utilization increased significantly from 2012 (n = 1,090,503) through 2018 (n = 1,209,489; p = 0.04). Although orthopaedic surgeons did not demonstrate significant changes in total utilization rates (p = 0.23), the average number of services per orthopaedic surgeon increased significantly (p = 0.02). Reflecting a substantial growth in the number of advanced practice providers (APPs) providing injections, there was a significant increase in utilization and associated costs among physician assistants (p < 0.01) and nurse practitioners (p < 0.01). Total costs associated with HA services increased significantly from $290.10 million to $325.02 million (p < 0.01).

CONCLUSIONS

Despite the 2013 American Academy of Orthopaedic Surgeons clinical practice guideline recommending against the clinical utility of these injections, HA services continued to be widely implemented among Medicare beneficiaries. Although there were variations across specialties when evaluating overall utilization rates as well as rates per provider, APPs largely contributed to the increase seen in the U.S. over this study period. More data are needed to support continued implementation and spending on this low-value care.

Chondroprotective Effects of 4,5-Dicaffeoylquinic Acid in Osteoarthritis through NF-κB Signaling Inhibition

Osteoarthritis (OA) is characterized by cartilage degradation, inflammation, and pain. The dicaffeoylquinic acid (diCQA) isomer, 4,5-diCQA, exhibits antioxidant activity and various other health-promoting benefits, but its chondroprotective effects have yet to be elucidated. In this study, we aimed to investigate the chondroprotective effects of 4,5-diCQA on OA both in vitro and in vivo. Primary rat chondrocytes were pre-treated with 4,5-diCQA for 1 h before stimulation with interleukin (IL)-1β (5 ng/mL). The accumulation of nitrite, PGE₂, and aggrecan was observed using the Griess reagent and ELISA. The protein levels of iNOS, COX-2, MMP-3, MMP-13, ADMATS-4, MAPKs, and the NF-κB p65 subunit were measured by Western blotting. In vivo, the effects of 4,5-diCQA were evaluated for 2 weeks in a destabilization of the medial meniscus (DMM)-surgery-induced OA rat model. 4,5-diCQA significantly inhibited IL-1β-induced expression of nitrite, iNOS, PGE₂, COX-2, MMP-3, MMP-13, and ADAMTS-4. 4,5-diCQA also decreased the IL-1β-induced degradation of aggrecan. It also suppressed the IL-1β-induced phosphorylation of MAPKs and translocation of the NF-κB p65 subunit to the nucleus. These findings indicate that 4,5-diCQA inhibits DMM-surgery-induced cartilage destruction and proteoglycan loss in vivo. 4,5-diCQA may be a potential therapeutic agent for the alleviation of OA progression. In this study, diclofenac was set to be administered once every two days, but it showed an effect on OA. These results may be used as basic data to suggest a new dosing method for diclofenac.

Two or four injections of platelet-rich plasma for osteoarthritic knee did not change synovial biomarkers but similarly improved clinical outcomes

We compared two and four intra-articular injections of platelet-rich plasma (PRP) in terms of changes of synovial cytokines and clinical outcomes. One hundred twenty-five patients having knee osteoarthritis (OA) underwent PRP injections at a 6-week interval. Before each PRP injection, synovial fluid aspiration was collected for investigation. Patients were divided into two or four intra-articular PRP injections (group A and B, respectively). Changes in synovial biomarkers were compared with the baseline levels of both groups, and clinical outcomes were evaluated until one year. Ninety-four patients who had completed synovial fluid collection were included for final evaluation, 51 in group A and 43 in group B. There were no differences in mean age, gender, body mass index (BMI), and radiographic OA grading. The average platelet count and white blood cell count in PRP were 430,000/µL and 200/ µL, respectively. There were no changes of synovial inflammatory cytokines (IL-1β, IL-6, IA-17A, and TNF-alpha), anti-inflammatory cytokines (IL-4, IL-10, IL-13, and IL-1RA), and growth factors (TGF-B1, VEGF, PDGF-AA, and PDGF-BB) between baseline levels and six weeks in group A, and 18 weeks in group B. Both groups had significantly improved clinical outcomes from six weeks including visual analog scale (VAS), patient-reported outcome measures [PROMs; Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index and Short Form-12 (SF-12)], with a significant delayed improvement of performance-based measures [PBMs; time up and go (TUG), 5-time sit to stand test (5 × SST), and 3-min walk test (3-min WT)]. In conclusion, two- or four-PRP intra-articular injection at a 6-week interval for knee OA demonstrated no changes of synovial cytokines and growth factors but similarly improved clinical outcomes from 6 weeks until 1 year.

Viscosupplementation in the Therapy for Osteoarthritic Knee

Osteoarthritis (OA) is a degenerative disease that is spreading worldwide due to an aging population. This is not simply a disease caused by worn out joints, but a complex disease accompanied by various mechanisms such as inflammatory reactions. Among various joints, knee joints show degenerative changes earlier than other joints because they carry most of the weight load, causing social-economic problems. In the case of OA of the knee that does not respond to relatively simple conservative treatments such as physical therapy or medication, intra-articular injection is preferred. However, intra-articular injection drugs have limited effectiveness and uncertainties. There are several intra-articular viscous supplement drugs such as hyaluronic acid. Tissue regeneration active materials such as polydeoxyribonucleotide and polynucleotide are also newly used. The objective of this paper was to compare effects of intra-articular supplementation drugs used for degenerative arthritis of the knee.