Evaluation and Treatment of Knee Pain: A Review

Inflammatory mechanisms underlying metabolic syndrome-associated and potential treatments

Objectives

Osteoarthritis (OA), a debilitating disease, has been recognized as a heterogenous disease, with metabolic syndrome-associated osteoarthritis (MetS-OA) emerging as a significant area of interest. Currently, the understanding of MOA remains limited, with a prevailing consensus attributing its etiology to the core components of metabolic syndrome: obesity, hyperglycemia, dyslipidemia, and hypertension. The aim of this review is to summarize the current understanding of the complex relationship between metabolic syndrome and OA from the perspectives of epidemiology and molecular biology, and to explore potential targeting strategies for metabolic syndrome in MetS-OA management.

Methods

This narrative review evaluated literature (2010-2024) from PubMed, examining clinical and mechanistic evidence linking metabolic syndrome to OA, including therapeutic studies targeting MetS-OA.

Results

Metabolic syndrome aggravate the cartilage injury in MetS-OA through metabolic biomarkers (adipokines, advanced glycation end-products and oxidized LDL), metabolic responses (oxidative stress, insulin resistance and ischemic hypoxic injuries), and abnormally activated cells (adipocytes and macrophages). It ultimately lead to the aggravation of synovitis in MetS-OA through inflammatory mediators.

Conclusions

The exploration of the relationship between metabolic syndrome and OA could benefit the development of targeting strategies for MetS-OA, including currently FDA-approved drugs for the treatment of metabolic syndrome and potential drugs targeting metabolic factors, which might provide a novel avenue for the future management of MetS-OA.

Comparison of predictive models for knee pain and analysis of individual and physical activity variables using interpretable machine learning

BACKGROUND

Knee pain is associated with not only individual factors such as age and obesity but also physical activity factors such as occupational activities and exercise, which has a significant impact on the lives of adults and the elderly.

OBJECTIVES

The purpose of this study was to construct a model for predicting knee pain using individual and physical activity variables and to determine the relationship between knee pain and individual and physical activity variables.

DESIGN

Observational study.

METHODS

A total of 19 variables related to individual and physical activity were used to create a knee pain prediction model. Model composition variables were selected using recursive feature elimination with cross validation. The performance of the model was evaluated using test data, and the relationship between knee pain and predictor variables was analyzed using SHapley Additive exPlanations (SHAP).

RESULTS

The CatBoost model showed the highest performance. And, activity limitation was identified as the most influential predictor, followed by weekly physical activity, body image, weight change, occupational type, age, BMI, and housing type.

CONCLUSION

Knee pain prediction models built with individual and physical activity variables can exhibit relatively high predictive performance, and interpretable machine learning models can provide valuable insight into the complex relationships between individual and physical activity variables and knee pain.

The effects of blood flow restriction combined with low-intensity resistance training on muscle strength and pain during postoperative recovery in patients with knee injuries: a meta-analysis

To investigate the effects of low-load blood flow restriction training (LL-BFRT) on muscle strength and pain during postoperative rehabilitation in patients with knee injuries. A systematic review and meta-analysis was conducted in accordance with PRISMA guidelines. Comprehensive searches through PubMed, EBSCO, Cochrane, Web of Science, and Embase yielded 1049 articles, of which 13 studies met the inclusion criteria. Quantitative analyses were performed using Review Manager 5.3 and Stata. LL-BFRT showed a significant positive effect on muscle strength, with a standardized mean difference (SMD) of 0.70 (p < 0.00001, 95%CI: 0.49, 0.92, I2 = 42%, p = 0.07). In terms of pain reduction, LL-BFRT significantly lowered the outcome of visual analog scale (VAS), with an SMD of -0.60 (p < 0.00001, 95% CI: -0.85, -0.36, I2 = 0%, p = 0.44). LL-BFRT effectively improves muscle strength and reduces pain in patients recovering from knee injuries postoperatively. It presents an alternative rehabilitation method for patients who are unable to perform high-intensity resistance training.

The effects of Tai Chi on clinical outcomes and gait biomechanics in knee osteoarthritis patients: a pilot randomized controlled trial

Knee osteoarthritis (KOA) is a common degenerative joint disease that significantly reduces mobility and quality of life in elderly populations. Tai Chi, a low-impact mind-body exercise, has been suggested as a potential non-pharmacological intervention for managing KOA, but its biomechanical effects remain unclear. This study aimed to evaluate the effects of a 14-week Tai Chi program on clinical symptoms, lower limb biomechanics, and muscle activation patterns in elderly patients with KOA. A single-blinded randomized controlled trial was conducted, enrolling 24 participants aged 55-70 years with unilateral KOA. Participants were randomly assigned to a Tai Chi intervention group or a control group receiving health education only. Primary outcomes included joint range of motion, joint moments, and muscle activation, measured using a motion capture system and surface electromyography. Secondary outcomes, such as pain, stiffness, function (WOMAC), balance (BBS), and quality of life (SF-12), were also assessed pre- and post-intervention. The Tai Chi group demonstrated significant improvements in WOMAC pain (-1.58 ± 1.44 vs. 0.11 ± 0.78, p = 0.01), stiffness (-0.33 ± 0.78 vs. 0.56 ± 0.88, p = 0.02), and function scores (-2.58 ± 3.53 vs. 1.00 ± 2.78, p = 0.02) compared to the control group. Balance (BBS: 1.42 ± 1.88 vs. -0.89 ± 1.27, p = 0.01) and physical health (SF-12 PCS: 5.45 ± 6.76 vs. -1.05 ± 2.17, p = 0.01) were also enhanced. Biomechanically, Tai Chi reduced horizontal plane knee ROM (-3.03 ± 1.00°, p = 0.01) and maximum knee extension moments (affected side: -0.09 ± 0.04 N/kg, p = 0.04, Non-affected side: -0.11 ± 0.05 N/kg, p = 0.03). Tibialis anterior muscle activation increased significantly (5.66 ± 1.05%MVIC, p = 0.02), while other muscles showed non-significant trends. Tai Chi demonstrated significant clinical and biomechanical benefits for elderly KOA patients, suggesting its potential as a safe, accessible, and effective therapeutic intervention.

Chest CT-determined sarcopenia is associated with poorer functional outcomes in osteoarthritis patients undergoing total knee arthroplasty: a retrospective cohort study

Sarcopenia diagnosed via opportunistic computed tomography (CT) is linked to poor postoperative outcomes. This study aimed to investigate the association between chest CT-diagnosed sarcopenia and post-total knee arthroplasty (TKA) functional outcomes. This single-center retrospective cohort study included 158 knee osteoarthritis (KOA) patients who underwent primary TKA between January 2021 and June 2022. Sarcopenia was defined using skeletal muscle index values derived from chest CT images at the T12 vertebral level. Sociodemographic, clinical, and perioperative data were collected, and functional outcomes were assessed via the Hospital for Special Surgery (HSS) score at 6 months postoperatively. Univariate and multivariate analyses identified independent risk factors for poorer postoperative functional outcomes in KOA patients undergoing TKA. The prevalence of sarcopenia in the cohort was 48.7%. At 6 months after TKA, sarcopenic patients had significantly lower HSS scores (P < 0.05). Advanced age (P = 0.025), higher body mass index (P = 0.027), sarcopenia (P = 0.020), and higher postoperative pain scores (P < 0.001) were independently associated with poorer functional outcomes. The results indicate that chest CT-determined sarcopenia is prevalent among KOA patients undergoing TKA and is significantly associated with poorer functional outcomes.

An Arthroscopic Robotic System for Meniscoplasty with Autonomous Operation Ability

Meniscoplasty is a common surgical procedure used to treat meniscus tears. During the operation, there are often key challenges such as a limited visual field, a narrow operating space, and difficulties in controlling the resection range. Therefore, this study developed an arthroscopic robotic system with the ability of autonomous meniscus resection to achieve better surgical outcomes. To address the issue of limited visual fields during the operation, this study used the preoperative and intraoperative meniscus point cloud images for surgical navigation and proposed a novel cross-modal point cloud registration framework. After the registration was completed, the robotic system automatically generated a resection path that could maintain the crescent shape of the remaining meniscus based on the improved Rapidly Exploring Random Tree (RRT) path-planning algorithm in this study. Meanwhile, the Remote Center of Motion (RCM) constraint was introduced during the movement of the robot to enhance safety. In this study, the mean squared error of the preoperative-intraoperative meniscus point cloud registration was only 0.1964 mm2, which meets the surgical accuracy requirements. We conducted experiments to validate the autonomous operation capabilities of the robot. The robot successfully completed motion-planning and autonomous implementation, thus demonstrating the reliability of the robotic system.

Musculoskeletal organoids: An emerging toolkit for establishing personalized models of musculoskeletal disorders and developing regenerative therapies

Musculoskeletal (MSK) conditions are the primary cause of physical disability globally. These disorders are physically and mentally debilitating and severely impact the patients' quality of life. As the median age of the world's population increases, there has been an intensifying urgency of developing efficacious therapies for various orthopaedic conditions. Furthermore, the highly heterogeneous nature of MSK conditions calls for a personalized approach to studying disease mechanisms and developing regenerative treatments. Organoids have emerged as an advanced approach to generating functional tissue/organ mimics in vitro, which hold promise in MSK regeneration, disease modeling, and therapeutic development. Herein, we review the preparation, characterization, and application of various MSK organoids. We highlight the potential of patient-specific organoids in the development of personalized medicine and discuss the challenges and opportunities in the future development of MSK organoids. STATEMENT OF SIGNIFICANCE: Despite decades of research, translation of MSK research into clinical applications remains limited, partially attributed to our inadequate understanding of disease mechanisms. To advance therapeutic development, there are critical needs for MSK disease models with higher clinical relevance and predictive power. Additionally, engineered constructs that closely mimic the structural and functional features of native MSK tissues are highly desirable. MSK organoids have emerged as a promising approach to meet the above requirements. To unleash the full potential of MSK organoids necessitates a comprehensive understanding of their categories, construction, development, functions, applications, and challenges. This review aims to fulfill this crucial need, aiming to accelerate the clinical translation of MSK organoid platforms to benefit millions of patients afflicted with MSK conditions.

The Perioperative Resource Use and Effectiveness of Patellofemoral Arthroplasty Versus Total Knee Arthroplasty: A Meta-Analysis

OBJECTIVE

Patellofemoral osteoarthritis (PFOA) is a common condition that significantly affects quality of life. With advancements in modern patellofemoral arthroplasty (PFA) prostheses, a growing number of surgeons are opting for PFA to treat isolated PFOA. This meta-analysis aimed to compare the perioperative resource use and therapeutic outcomes of PFA versus total knee arthroplasty (TKA) in patients with isolated PFOA.

METHODS

A literature search was conducted in PubMed, EMBASE, the Cochrane Library, and the Web of Science until November 2024. The included studies provided direct comparisons of perioperative resource use (surgical time, blood loss, and length of stay) and postoperative outcomes (patient-reported outcome measures [PROMs], quality of life, and patient satisfaction) between modern PFA and TKA in patients with isolated PFOA. The Cochrane risk of bias assessment tool was applied to randomized controlled trials, and the modified Newcastle-Ottawa Scale was used for observational studies to evaluate methodological quality and risk of bias. Data was extracted from eligible studies and combined to calculate the mean difference (MD) or pooled relative risk with a 95% confidence interval (CI).

RESULTS

We included eight eligible studies with a mean follow-up duration of 2-10 years. Compared with TKA, modern PFA demonstrated significantly shorter surgical times (MD = -13.67 min; 95% CI: -20.47 to -6.86) and reduced perioperative blood loss. However, no significant difference was observed in hospital length of stay. Regarding PROMs, PFA showed superior functional outcomes on the Oxford Knee Score (OKS) within 2 years postoperatively (MD = -2.02; 95% CI: -3.77 to -0.26). No significant differences were found between PFA and TKA at 12-month follow-up for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score (MD = -5.68; 95% CI: -21.54 to 10.18) or total WOMAC score (MD = -6.65; 95% CI: -30.00 to 16.70). Similarly, at 24-month follow-up, no differences were observed in the University of California, Los Angeles activity score (MD = -0.02; 95% CI: -1.79 to 1.75) or final OKS (MD = -1.09; 95% CI: -6.31 to 4.14). Quality of life and patient satisfaction remained comparable between the two procedures throughout the first 2 years and final follow-up.

CONCLUSIONS

PFA demonstrates comparable efficacy to TKA in isolated PFOA, with superior early functional recovery within the first 2 years post-surgery, shorter surgical duration, and reduced blood loss. These findings suggest PFA may be a resource-efficient alternative for eligible patients.

Comparing Artificial Intelligence-Generated and Clinician-Created Personalized Self-Management Guidance for Patients With Knee Osteoarthritis: Blinded Observational Study

BACKGROUND

Knee osteoarthritis is a prevalent, chronic musculoskeletal disorder that impairs mobility and quality of life. Personalized patient education aims to improve self-management and adherence; yet, its delivery is often limited by time constraints, clinician workload, and the heterogeneity of patient needs. Recent advances in large language models offer potential solutions. GPT-4 (OpenAI), distinguished by its long-context reasoning and adoption in clinical artificial intelligence research, emerged as a leading candidate for personalized health communication. However, its application in generating condition-specific educational guidance remains underexplored, and concerns about misinformation, personalization limits, and ethical oversight remain.

OBJECTIVE

We evaluated GPT-4's ability to generate individualized self-management guidance for patients with knee osteoarthritis in comparison with clinician-created content.

METHODS

This 2-phase, double-blind, observational study used data from 50 patients previously enrolled in a registered randomized trial. In phase 1, 2 orthopedic clinicians each generated personalized education materials for 25 patient profiles using anonymized clinical data, including history, symptoms, and lifestyle. In phase 2, the same datasets were processed by GPT-4 using standardized prompts. All content was anonymized and evaluated by 2 independent, blinded clinical experts using validated scoring systems. Evaluation criteria included efficiency, readability (Flesch-Kincaid, Gunning Fog, Coleman-Liau, and Simple Measure of Gobbledygook), accuracy, personalization, and comprehensiveness and safety. Disagreements between reviewers were resolved through consensus or third-party adjudication.

RESULTS

GPT-4 outperformed clinicians in content generation speed (530.03 vs 37.29 words per min, P<.001). Readability was better on the Flesch-Kincaid (mean 11.56, SD 1.08 vs mean 12.67 SD 0.95), Gunning Fog (mean 12.47, SD 1.36 vs mean 14.56, SD 0.93), and Simple Measure of Gobbledygook (mean 13.33, SD 1.00 vs mean 13.81 SD 0.69) indices (all P<.001), though GPT-4 scored slightly higher on the Coleman-Liau Index (mean 15.90, SD 1.03 vs mean 15.15, SD 0.91). GPT-4 also outperformed clinicians in accuracy (mean 5.31, SD 1.73 vs mean 4.76, SD 1.10; P=.05, personalization (mean 54.32, SD 6.21 vs mean 33.20, SD 5.40; P<.001), comprehensiveness (mean 51.74, SD 6.47 vs mean 35.26, SD 6.66; P<.001), and safety (median 61, IQR 58-66 vs median 50, IQR 47-55.25; P<.001).

CONCLUSIONS

GPT-4 could generate personalized self-management guidance for knee osteoarthritis with greater efficiency, accuracy, personalization, comprehensiveness, and safety than clinician-generated content, as assessed using standardized, guideline-aligned evaluation frameworks. These findings underscore the potential of large language models to support scalable, high-quality patient education in chronic disease management. The observed lexical complexity suggests the need to refine outputs for populations with limited health literacy. As an exploratory, single-center study, these results warrant confirmation in larger, multicenter cohorts with diverse demographic profiles. Future implementation should be guided by ethical and operational safeguards, including data privacy, transparency, and the delineation of clinical responsibility. Hybrid models integrating artificial intelligence-generated content with clinician oversight may offer a pragmatic path forward.

The Large Language Model ChatGPT-4 Exhibits Excellent Triage Capabilities and Diagnostic Performance for Patients Presenting With Various Causes of Knee Pain

PURPOSE

To provide a proof-of-concept analysis of the appropriateness and performance of ChatGPT-4 to triage, synthesize differential diagnoses, and generate treatment plans concerning common presentations of knee pain.

METHODS

Twenty knee complaints warranting triage and expanded scenarios were input into ChatGPT-4, with memory cleared prior to each new input to mitigate bias. For the 10 triage complaints, ChatGPT-4 was asked to generate a differential diagnosis that was graded for accuracy and suitability in comparison to a differential created by 2 orthopaedic sports medicine physicians. For the 10 clinical scenarios, ChatGPT-4 was prompted to provide treatment guidance for the patient, which was again graded. To test the higher-order capabilities of ChatGPT-4, further inquiry into these specific management recommendations was performed and graded.

RESULTS

All ChatGPT-4 diagnoses were deemed appropriate within the spectrum of potential pathologies on a differential. The top diagnosis on the differential was identical between surgeons and ChatGPT-4 for 70% of scenarios, and the top diagnosis provided by the surgeon appeared as either the first or second diagnosis in 90% of scenarios. Overall, 16 of 30 diagnoses (53.3%) in the differential were identical. When provided with 10 expanded vignettes with a single diagnosis, the accuracy of ChatGPT-4 increased to 100%, with the suitability of management graded as appropriate in 90% of cases. Specific information pertaining to conservative management, surgical approaches, and related treatments was appropriate and accurate in 100% of cases.

CONCLUSIONS

ChatGPT-4 provided clinically reasonable diagnoses to triage patient complaints of knee pain due to various underlying conditions that were generally consistent with differentials provided by sports medicine physicians. Diagnostic performance was enhanced when providing additional information, allowing ChatGPT-4 to reach high predictive accuracy for recommendations concerning management and treatment options. However, ChatGPT-4 may show clinically important error rates for diagnosis depending on prompting strategy and information provided; therefore, further refinements are necessary prior to implementation into clinical workflows.

CLINICAL RELEVANCE

Although ChatGPT-4 is increasingly being used by patients for health information, the potential for ChatGPT-4 to serve as a clinical support tool is unclear. In this study, we found that ChatGPT-4 was frequently able to diagnose and triage knee complaints appropriately as rated by sports medicine surgeons, suggesting that it may eventually be a useful clinical support tool.

UGDH Lactylation Aggravates Osteoarthritis by Suppressing Glycosaminoglycan Synthesis and Orchestrating Nucleocytoplasmic Transport to Activate MAPK Signaling

Osteoarthritis (OA) progression is closely related to dysregulated glycolysis. As the primary metabolite of glycolysis, lactate plays a detrimental role in OA. However, how lactate exacerbates OA process remains unclear. Here, this study revealed that lactate levels are elevated in the synovial fluid of OA patients and IL-1β-treated human primary chondrocytes, promoting protein pan-lactylation. Functionally, hyper-lactylation exacerbates chondrocytes extracellular matrix (ECM) degradation and cell apoptosis in vitro and in vivo. Moreover, UDP-glucose dehydrogenase (UGDH) is proven to be the key lactylated protein in lactate-treated chondrocytes, which undergoes lactylation at lysine 6 (K6). Lactylated UGDH repressed its enzymatic activity, reducing glycosaminoglycan synthesis and disregulating its nuclear-cytoplasmic distribution. Mechanistically, K6 lactylation of UGDH impedes the interaction of UGDH and signal transducer and activator of transcription 1 (STAT1), thus promoting the transcription of mitogen-activated protein kinase kinase kinase 8 (MAP3K8) and activating the MAPK signaling pathway. Importantly, in vitro and in vivo treatment with A485, a specific acyltransferase P300 inhibitor, suppressed UGDH lactylation and rescued chondrocytes ECM degradation and OA progression. These findings uncover a new mechanism underlying OA pathogenesis and highlight the potential of targeting UGDH lactylation as a novel therapeutic strategy for OA.

Evaluation of infrapatellar fat pad elasticity in knee osteoarthritis using IVIM-DWI-based virtual MR elastography: repeatability and reproducibility analysis

BACKGROUND

Fibrosis of the infrapatellar fat pad (IPFP) leads to changes in its stiffness, which may impact knee osteoarthritis. However, few studies have utilized virtual MR elastography to assess the variations of the IPFP. This study aimed to evaluate the value of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI)-based virtual MR elastography (vMRE) in the IPFP by assessing the test-retest repeatability, as well as intra- and inter-observer reproducibility.

METHODS

A total of 71 subjects underwent IVIM-DWI examinations, which were conducted twice with an interval of 30-60 min using an 18-channel knee coil at 3T. Shifted apparent diffusion coefficient (sADC) was calculated from two different sets of b-values (b = 200/800 sec/mm2 and 200/1500 sec/mm2) and then converted to IVIM-DWI MRI-based virtual shear modulus (μdiff_800 and μdiff_1500). Two readers independently delineated regions of interest (ROI) within the IPFP on the vMRE stiffness map to obtain the mean and standard deviation (SD) values of μdiff. Short-term test-retest repeatability, as well as intra- and inter-observer agreement were assessed using the intra-class correlation coefficient (ICC), the coefficient of variation (CoV), and Bland-Altman limits of agreement (LoA).

RESULTS

The mean and SD values of μdiff_1500, along with the mean value of μdiff_800 exhibited excellent intra- and inter-observer reproducibility agreement (ICC ≥ 0.90 and CoV ≤ 10%, P˂ 0.001). The intra- and inter-observer ICCs for the mean values of μdiff_800 were 0.917 and 0.901, respectively, while the ICCs for the SD values of μdiff_800 were 0.870 and 0.863, with CoV exceeding 10% (P˂ 0.001). The test-retest repeatability of the average value of μdiff_1500 was excellent (ICC = 0.902; CoV = 6.8%) compared to μdiff_800 (ICC = 0.877; CoV = 15.3%). Test-retest repeatability of SD for μdiff_1500 was good (ICC = 0.803; CoV = 11.5%) in comparison to SD for μdiff_800 (ICC = 0.796; CoV = 13.5%).

CONCLUSIONS

IVIM-DWI-based vMRE demonstrated significant potential as a reliable tool for measuring tissue elasticity in the IPFP, exhibiting higher repeatability for μdiff_1500 than for μdiff_800.

MRI-based radiomics to determine the role of thigh muscle quality in the development of knee osteoarthritis: A discovery and validation study

INTRODUCTION

Although the reduced muscle quality is common in elderly people, its role in the development of knee osteoarthritis (OA) remains unclear. Magnetic Resonance Imaging (MRI) is considered the gold standard imaging modality to assess muscle quality, which might holistically capture the underlying pathology.

OBJECTIVES

This study aimed to apply MRI-based radiomics to assess the quality of thigh muscles comprehensively, and examine its prediction performance for incident knee OA.

METHODS

The participants at risk of knee OA during the 48-month visit were selected from a multicenter cohort and analyzed using a nested case-control design. Cases were matched 1:1 to controls according to age, sex, and contralateral knee status. A multitask framework was developed to comprehensively evaluate thigh muscle quality by calculating conventional quantitative markers and radiomic features. Baseline collected thigh and knee MRI scans were respectively used for discovery and validation procedures. In each procedure, three (cross-sectional area [CSA], intramuscular adipose tissue [intra-MAT] CSA, and radiomic signature score [Rad-score]) imaging models of each muscle group (extensors, flexors, and auxiliaries) were trained and tested. The prediction performance of each muscle Rad-score was compared with conventional markers respectively. Furthermore, the incremental predictive value of clinical characteristics for Rad-score model was investigated.

RESULTS

448 participants (mean age 61 years, 63 % female) were identified and split into training (314 [70.1 %]) and testing (134 [29.9 %]) cohorts. In the discovery procedure, the extensors Rad-score provided superior prediction performance than extensors CSA and intra-MAT CSA (area under the curve [AUC] 0.832 [95 % CI 0.765-0.899] vs 0.595 [0.498-0.692] and 0.600 [0.503-0.697] in testing cohort; all p < 0.001). Contrarily, the performances of the Rad-score and conventional markers of flexors were relatively poor, as were those of the auxiliaries. Extensors Rad-score also outperformed auxiliaries Rad-score, flexors Rad-score, and the clinical model (AUC 0.832 [0.765-0.899] vs 0.687 [0.597-0.777], 0.634 [0.541-0.728], and 0.577 [0.483-0.671] in testing cohort; all p < 0.001). Unexpectedly, the integration of other radiomic signatures and clinical characteristics showed comparable net benefit in decision curve analysis when compared with extensors Rad-score alone. Similar findings were obtained in the validation procedure.

CONCLUSION

MRI-based radiomics could enable comprehensive assessment of muscle quality and allow exact prediction of incident knee OA, which helps uncover the precursory role of reduced extensors quality in developing knee OA. The radiomic signature from extensors would be an alternative indicator for future diagnosis and treatment in knee OA.

The effect of mild to moderate knee osteoarthritis on gait and three-dimensional biomechanical alterations

Background

Knee Osteoarthritis (KOA) is a prevalent chronic degenerative joint disease, particularly among the elderly, leading to pain, stiffness, and diminished functionality. The progression of KOA is often associated with significant changes in gait and biomechanics, yet detailed investigations of these changes-especially in early to moderate stages-remain limited. This study aims to conduct a comparative analysis of three-dimensional gait biomechanics in patients with mild to moderate KOA, in order to gain deeper insights into the early biomechanical changes associated with KOA.

Methods

A case-control study design was employed, consisting of three groups: Kellgren-Lawrence (K-L) grade I KOA patients, K-L grade II KOA patients, and healthy controls, with 15 participants in each group. Kinetic and kinematic data were collected using two force plates and a three-dimensional motion capture system. Gait parameters, joint range of motion (ROM), angular velocities, and joint moments were analyzed, with a significance level of p < 0.05.

Results

Grade II KOA patients showed prolonged gait cycles, wider step widths, and reduced swing phases on the affected side compared to grade I patients and controls. Grade I patients had reduced hip and knee ROM compared to controls. In the sagittal plane, grade II patients had more significant reductions in knee and ankle ROM. In the coronal plane, grade II patients had less hip and ankle ROM than grade I and controls. Horizontally, grade II patients had greater hip ROM but reduced knee ROM compared to grade I. Additionally, grade I patients showed smaller extension moments in the hip and knee than controls. Grade II patients had lower angular velocities and reduced extension and flexion moments in the hip and knee compared to controls.

Conclusion

KOA induces significant biomechanical alterations in gait, which become more pronounced with advancing disease severity. These changes highlight the importance of early detection and tailored rehabilitation strategies to improve mobility and prevent further joint degeneration. Understanding the biomechanical profile of KOA at different stages is essential for developing personalized therapeutic approaches aimed at enhancing patient quality of life and reducing the societal burden of KOA.

Hospital and Patient Factors Associated With Length of Hospitalization in Patients Who Have Osteoarthritis Undergoing Primary Total Knee Arthroplasty: An Analysis of National Data

BACKGROUND

By 2040, an estimated 3.5 million primary total knee arthroplasties (TKAs) are expected to be performed annually in the United States. Osteoarthritis (OA) is the most common indication for primary TKA. We examined the association of hospital, regional, and patient-level factors with extended lengths of hospital stay (eLOS).

METHODS

We studied patients who have OA who underwent primary TKA from 2016 to 2019 using a national inpatient database. We used the International Classification of Diseases codes to identify diagnoses and procedures. There were 2,592,469 patients who had OA who underwent primary TKA from 2016 to 2019. We used univariate and multivariable-adjusted logistic regression analyses to assess whether patient, payer, hospital, and geographic factors were associated with an eLOS. Predictive probabilities from multivariable analyses were used to estimate the area under the curve.

RESULTS

Patient race and ethnicity, Medicaid or Medicare payer status, income, age/sex, and nearly all regional and hospital characteristics were independently associated with eLOS (>3 days; receiver-operating characteristic C-statistic = 0.74). Sensitivity analyses that used the most recent years of data from 2020 to 2021 (COVID-19 pandemic years) or adjusted for individual organ system complications reproduced the main results without much attenuation.

CONCLUSIONS

Age, sex, race, ethnicity, hospital location and teaching status, elective procedure designation, perioperative complications, and insurance payer status significantly influenced the LOS for primary TKA hospitalizations in the United States. Recognized disparities were linked to longer hospital stays after primary TKA in patients who had OA. Implementing policies and interventions that target these factors could help shorten hospital stays for high-risk patients after primary TKA.

Efficacy and safety of loxoprofen sodium cataplasms in the treatment of osteoarthritis: A randomized, multicenter study

The present study aimed to compare the efficacy and safety of loxoprofen sodium cataplasm (LSC) with those of flurbiprofen cataplasm (FPC) in osteoarthritis (OA) treatment. In this multicenter, randomized controlled trial, subjects meeting the inclusion and exclusion criteria were randomly assigned to the two treatment groups. According to the manufacturer's instructions, the first group received LSC once daily, with the application of one patch per area for 2 weeks, whereas the second group received FPC twice daily, with the application of one patch per area for 2 weeks. The treatment response was evaluated based on the Visual Analog Scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) global score, Lysholm score and adverse events for 296 patients enrolled across three subcenters, with 192 patients in the LSC group and 104 patients in the FPC group. The treatment effectiveness rates, based on the VAS, WOMAC global and Lysholm scores, were 74.46, 61.41 and 85.25%, respectively, for the LSC group and 43.14, 31.37 and 66.67%, respectively, for the FPC group. Regardless of the effectiveness criterion used, the LSC group exhibited a superior treatment effectiveness rate compared with the FPC group. After 2 weeks of treatment, OA symptoms improved in both groups, with the LSC group exhibiting lower VAS (P<0.05) and WOMAC global scores (comprising pain, stiffness and physical function scores) compared with the FPC group (P<0.05), while the Lysholm score was higher in the LSC group compared with the FPC group (P<0.05). The FPC group experienced more general adverse events (P>0.05) and dressing shedding (P<0.05) compared with the LSC group, whereas the LSC group had more specific adverse events (such as skin itching, fever and allergy) compared with the FPC group (P>0.05). The results suggested that compared with FPC, LSC exhibited higher short-term efficacy and a consistent safety profile. The present study was registered at Chinese Clinical Trial Register (chictr.org.cn; ChiCTR2300072504; date of registration, June 15, 2023).

Yoga or Strengthening Exercise for Knee Osteoarthritis: A Randomized Clinical Trial

Importance

There is limited evidence on the comparative effectiveness of different exercise modalities, such as yoga and strengthening exercises, for managing knee osteoarthritis (OA).

Objective

To compare the effectiveness of yoga vs strengthening exercise for reducing knee pain over 12 weeks in patients with knee OA.

Design, Setting, and Participants

This single-center, assessor-blinded (for nonpatient-reported outcomes), parallel-arm, active-controlled, superiority randomized clinical trial included adults aged 40 years or older with knee OA and knee pain levels of 40 or higher on a 100-mm visual analog scale (VAS) in Southern Tasmania, Australia. Participants were recruited from April 2021 to June 2022, and follow-up was completed in December 2022. Data were analyzed from May 2023 to July 2024.

Interventions

Participants were randomized 1:1 to the yoga and strengthening exercise groups. Both groups attended 2 supervised and 1 home-based session per week for 12 weeks followed by 3 unsupervised home-based sessions per week for weeks 13 to 24.

Main Outcomes and Measures

The primary outcome was the between-group difference in VAS score over 12 weeks assessed using a range of 0 (no pain) to 100 (worst possible pain) with a prespecified noninferiority margin of 10 mm. Secondary outcomes included knee pain over 24 weeks; Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) knee pain, function, and stiffness; patient global assessment; Osteoarthritis Research Society International-Outcome Measures in Rheumatology Clinical Trials response; physical performance measures; leg muscle strength; health-related quality of life assessed via the Assessment of Quality of Life-8 Dimensions (AQol-8D) utility score; depression assessed with the Patient Health Questionnaire-9; and neuropathic pain assessment over 12 and 24 weeks. Analyses were based on the intention-to-treat principle.

Results

In total, 117 participants were randomized to the yoga (n = 58) or strengthening exercise (n = 59) program. Baseline characteristics of the participants were similar, with a mean (SD) age of 62.5 (8.3) years, and 85 participants (72.6%) were female. The mean (SD) baseline VAS knee pain score of 53.8 (16.0) indicated moderate knee pain. Over 12 weeks, the between-group mean difference in VAS knee pain change was -1.1 mm (95% CI, -7.8 to 5.7 mm), which was not statistically significant but remained within the prespecified noninferiority margin. Of 27 secondary outcomes assessed over 12 and 24 weeks, 7 were statistically significant in favor of yoga. The yoga group showed modestly greater improvements than the strengthening exercise group (between-group differences) over 24 weeks for WOMAC pain (-44.5 mm [95% CI, -70.7 to -18.3 mm]), WOMAC function (-139 mm [95% CI, -228.3 to -49.7 mm]), WOMAC stiffness (-17.6 mm [95% CI, -30.9 to -4.3 mm]), patient global assessment (-7.6 mm [95% CI, -15.1 to -0.2 mm]), and 40-m fast-paced walk test (1.8 [95% CI, 0.4-3.2]). In addition, the yoga group had a modestly greater improvement than the strengthening exercise for depression at 12 weeks (between-group difference in PHQ-9 score, -1.1 [95% CI, -1.9 to -0.2]) and quality of life at 24 weeks (between-group difference in AQoL-8D score, 0.04 [95% CI, 0.0 to 0.07]). Adverse events were similar in both groups and mild.

Conclusion and relevance

In this randomized clinical trial, yoga did not significantly reduce knee pain compared with strengthening exercises. However, yoga was found to be noninferior to strengthening exercises, suggesting that integrating yoga as an alternative or complementary exercise option in clinical practice may help in managing knee OA.

Trial registration

ANZCTR.org Identifier: ACTRN12621000066886.

LIPUS Promotes Calcium Oscillation and Enhances Calcium Dependent Autophagy of Chondrocytes to Alleviate Osteoarthritis

Osteoarthritis (OA) is a degenerative disease which places an enormous burden on society, effective treatments are still limited. As a non-invasive and safe physical therapy, low-intensity pulsed ultrasound (LIPUS) can alleviate OA progression, but the underlying mechanism is not fully understood, especially the mechanical transduction between LIPUS and the organism. In this pioneering study, the biomechanical effects of LIPUS on living mice chondrocytes and living body zebrafish are investigate by using fluorescence imaging technology, to dynamically "visualize" its invisible mechanical stimuli in the form of calcium oscillations. It is also confirmed that LIPUS maintains cartilage homeostasis by promoting chondrocyte autophagy in a calcium-dependent manner. In addition, chondrocyte ion channels are screened by scRNA-seq and confirm that the mechanosensitive ion channel transient receptor potential vanilloid 4 (TRPV4) mediated the biological effects of LIPUS on chondrocytes. Finally, it is found that a combination of pharmacologically induced and LIPUS-induced Ca2+ influx in chondrocytes enhances the cartilage-protective effect of LIPUS, which may provide new insights for optimizing LIPUS in the treatment of OA.

Oxytocin-loaded hydrogel promotes cartilage regeneration and regulates microenvironment

Osteoarthritis is a common orthopedic condition, and traditional treatment methods often fail to regenerate cartilage effectively. Oxytocin (OXT) is a neuropeptide that plays a crucial role in the skeletal system. Hyaluronic acid (HAMA) hydrogel has emerged as a key carrier for cartilage repair due to its excellent biocompatibility and biodegradability. Combining OXT with HAMA hydrogel and implanting it at the site of cartilage defects can effectively promote cartilage regeneration. Cartilage damage often results in an altered microenvironment, characterized by macrophage polarization and high levels of reactive oxygen species (ROS). Oxidative stress can stimulate macrophages to produce more pro-inflammatory factors. OXT can inhibit the secretion of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1βby interacting with the STAT3/NF-κB signaling pathway, as well as the PI3K/Akt and mitogen-activated protein kinase pathways, thereby inducing the polarization of macrophages from the M1 phenotype to the M2 phenotype and alleviating the inflammatory response. OXT can also enhance the expression of NRF and HO-1, which helps eliminate ROS and suppress the expression of pro-inflammatory factors. Regulating the microenvironment of cartilage damage is beneficial for cartilage protection and repair. OXT activates the CFOS/AP-1 and STAT1/JAK2 pathways, which together act on MMP2 and MMP9 to alleviate cartilage degeneration. The STAT1/JAK2 pathway can further increase the expression of Col2, thereby protecting chondrocytes. Additionally, OXT can directly boost the protein levels of SOX9 and COMP, promoting chondrocyte proliferation and cartilage protection, ultimately achieving the therapeutic goal for arthritis. This study explores the potential of HAMA hydrogel as a delivery system for OXT and analyzes their impact on cartilage regeneration and anti-inflammatory properties. This research provides a novel strategy for the treatment of cartilage injuries.

TRIM15 drives chondrocyte senescence and osteoarthritis progression

Osteoarthritis (OA) is a prevalent joint disease characterized by pain, disability, and loss of physical function, posing a challenge to public health. However, molecular mechanisms of OA pathogenesis have not been fully described. We report that tripartite motif containing 15 (TRIM15) is a regulator in chondrocyte senescence and OA. Our study revealed heightened expression of TRIM15 in chondrocytes of senescent cartilage from patients with OA and in aged wild-type mice. Using gain- and loss-of-function studies, we found that TRIM15 facilitated human chondrocyte senescence. Conditional deletion of Trim15 in mouse chondrocytes severely impaired skeletal growth, partially because of impaired embryonic chondrocyte senescence. Compared with conditionally knocked out Col2a1-CreERT2/Trim15flox/flox mice, Trim15flox/flox control mice exhibited accelerated OA phenotypes, increased senescence markers, and senescence-associated secretory phenotype during aging. Mechanistically, TRIM15 bound with yes-associated protein (YAP) and mediated K48-linked YAP ubiquitination at K254, which interrupted the interaction between YAP and angiomotin, leading to enhanced YAP nuclear translocation. Dysregulation of TRIM15-YAP and transcriptional coactivator with PDZ-binding motif (TAZ) signaling promoted OA progression in both the surgery-induced and natural aging-induced mouse OA model. Intra-articular injection of adeno-associated virus 5 (AAV5)-Trim15 shRNA decelerated OA progression in mice. In particular, YAP and TAZ protein amounts were increased in chondrocytes of patients with OA. Our preclinical results demonstrated that the AAV5-TRIM15 shRNA treatment protected human OA explants against degeneration through inhibiting chondrocyte senescence. Together, our findings underscore the potential of targeting TRIM15 in reshaping the aging cartilage microenvironment and suggest a promising therapeutic avenue for OA.

Research on the biomechanical characteristics of the tibiofemoral joint before and after kinematic alignment unicompartmental knee arthroplasty

BACKGROUND

Kinematic alignment (KA) unicompartmental knee arthroplasty (UKA), which has not been widely adopted in clinical practice, aims to implant a more personalized and physiologically compatible mobile-bearing UKA prosthesis for the treatment of advanced single compartment knee osteoarthritis. KA UKA is anticipated to enhance patient satisfaction and decrease the revision rate following UKA. However, its quantified biomechanical indicators remain unclear. The purpose of this study is to reveal the biomechanical characteristics of the tibiofemoral joint in normal and KA UKA knees, and to evaluate the biomechanical effect.

METHODS

In this study, six cadaveric knee joint specimens were utilized for biomechanical testing before (normal cadaveric knee joint specimen ) and after KA UKA. The knee joint specimens were subjected to an axial load of 1000 N, and the biomechanical parameters were assessed at flexion angles ranging from 0° to 120° in 10° increments.

RESULTS

The root mean square (RMS) values of the tibiofemoral contact area, mean contact pressure, and peak contact pressure during knee flexion were 529 mm², 1.8 MPa, and 4.5 MPa in normal knees, respectively. After KA UKA, these values changed to 449 mm², 2.0 MPa, and 9.8 MPa, respectively. Additionally, the RMS value of the external rotation of the femur relative to the tibia in the tibiofemoral joint was 9.9° in normal knees, while the posterior translations of the center of the femoral condyle, the medial femoral condyle, and the lateral femoral condyle were 18.4 mm, 11.5 mm, and 25.4 mm respectively. After KA UKA, these values changed to 8.6°, 19.3 mm, 12.9 mm, and 25.9 mm respectively.

CONCLUSION

At the same flexion angle, the increase in peak contact pressure in the medial compartment after KA UKA is the most significant compared with the normal knees. However, the kinematic characteristics do not change significantly after KA UKA. These findings are beneficial for understanding the possible postoperative complications and good functional effects of KA UKA.

Microalgae-Derived Extracellular Vesicles Synergize with Herbal Hydrogel for Energy Homeostasis in Osteoarthritis Treatment

Treatment of osteoarthritis (OA) remains challenging owing to its complex pathological microenvironment, which involves reactive oxygen species, chronic inflammation, mitochondrial dysfunction, energy deficiency, and cartilage degeneration. Herein, we report for extracellular vesicles (SP-EVs) derived from the photosynthetic microorganism Spirulina platensis contain antioxidative and ATP-dependent active and metabolic-related compounds for OA treatment. SP-EVs were effectively delivered to chondrocytes, demonstrating the potential for modulating cellular communication and energy homeostasis. To facilitate sustained delivery of SP-EVs, the rhein hydrogel system was used for intra-articular injection (Rh Gel@SP-EVs), which demonstrated pH responsiveness under mildly acidic conditions and synergistic anti-inflammatory effects. Rh Gel@SP-EVs significantly rescued mitochondrial dysfunction by ameliorating inflammation-mediated oxidative stress and restoring the mitochondrial membrane potential in chondrocytes. Improved mitochondrial function facilitates the replenishment of ATP levels, further contributing to the balance of anabolic and catabolic processes within the cartilage matrix, eventually decelerating OA progression. Rh Gel@SP-EVs also modulated the Janus kinase-signal transducer and activator of transcription 3 signaling pathway, implicated in suppressing inflammatory responses. This therapeutic strategy utilized a microalgae-based herbal hydrogel system to modulate the sustained release of SP-EVs, offering an effective approach for treating OA by regulating energy metabolism and anti-inflammatory mechanisms.

Targeting p21-Positive Senescent Chondrocytes via IL-6R/JAK2 Inhibition to Alleviate Osteoarthritis

Osteoarthritis (OA) is an age-related degenerative joint disease, prominently influenced by the pro-inflammatory cytokine interleukin-6 (IL-6). Although elevated IL-6 levels in joint fluid are well-documented, the uneven cartilage degeneration observed in knee OA patients suggests additional underlying mechanisms. This study investigates the role of interleukin-6 receptor (IL-6R) in mediating IL-6 signaling and its contribution to OA progression. Here, significantly elevated IL-6R expression is identified in degenerated cartilage of OA patients. Further, in vivo experiments reveal that intra-articular injection of recombinant IL-6R protein or activation of gp130 (Y757F mutation) accelerates OA progression. Conversely, knockout of IL-6R or JAK2, as well as treatment with a JAK inhibitor, alleviates OA symptoms. Mechanistically, chondrocytes derived from degenerative cartilage exhibit impaired nuclear localization of SOX9, a key regulator of cartilage homeostasis. JAK inhibition stabilizes SIRT1, reduces SOX9 acetylation, and thereby facilitates SOX9 nuclear localization, promoting cartilage repair. Additionally, the JAK inhibitor-induced apoptosis in p21-positive senescent cells, and their targeted clearance successfully alleviates OA in p21-3MR mice. In conclusion, these findings reveal a novel mechanism by which inhibiting the IL-6R/JAK2 pathway can alleviate OA. Furthermore, this study proposes targeting p21-positive senescent cells as a new therapeutic strategy for OA.

Exosomes of stem cells: a potential frontier in the treatment of osteoarthritis

The aging population has led to a global issue of osteoarthritis (OA), which not only impacts the quality of life for patients but also poses a significant economic burden on society. While biotherapy offers hope for OA treatment, currently available treatments are unable to delay or prevent the onset or progression of OA. Recent studies have shown that as nanoscale bioactive substances that mediate cell communication, exosomes from stem cell sources have led to some breakthroughs in the treatment of OA and have important clinical significance. This paper summarizes the mechanism and function of stem cell exosomes in delaying OA and looks forward to the development prospects and challenges of exosomes.

Chronic knee pain while awaiting arthroplasty is associated with worsening joint-specific function, health-related quality of life and personal wellbeing, and increased use of opioid analgesia

Aims

To assess whether chronic knee pain (CKP) influenced health-related quality of life (HRQoL), knee-specific health, wellbeing, and use of opioid analgesia, and identify variables associated with CKP in patients awaiting knee arthroplasty.

Methods

This study included 217 patients (mean age 69.7 years (SD 8.7), 116 female (53%)) who completed questionnaires that included the EuroQol five-dimension questionnaire (EQ-5D) and EuroQol-visual analogue scale (EQ-VAS), Oxford Knee Score (OKS), and wellbeing assessments at six and 12 months after being listed for surgery. Analgesia use at 12 months was also recorded. CKP was defined using the OKS pain score (PS) of ≤ 14 points at 12 months.

Results

At 12 months, 169 patients (77.9%) had CKP. Compared with those without CKP, those with CKP had clinically meaningfully worse HRQoL and knee-specific health at 12 months and were more likely to have a health state worse than death (odds ratio (OR) 29.7, 95% CI 4.0 to 220.2; p < 0.001). The CKP group were more likely to use weak (OR 3.03, 95% CI 1.65 to 7.96; p = 0.001) and strong (OR 11.8, 95% CI 1.58 to 88.88; p = 0.001) opioids for analgesia. The CKP group had worse overall wellbeing with significantly (p < 0.001) lower satisfaction with life, life being worthwhile and happiness, and increased anxiety. The CKP group had a significant (p < 0.001) deterioration in their OKS, OKS-PS, EQ-5D, and EQ-VAS from six to 12 months, which was not observed in the group without CKP. A worse OKS-PS at six months was independently associated with an increased risk of CKP, and a threshold value of < 13 (sensitivity 91.7%, specificity 94.7%) was an excellent discriminator (area under the curve 96.9, 95% CI 94.2 to 99.6; p < 0.001).

Conclusion

Four in five patients had CKP after waiting 12 months, which was associated with deteriorations in HRQoL and knee health, worse wellbeing, and increased opioid analgesia use. The OKS-PS at six months could be used to identify patients at risk of CKP after 12 months of waiting.

ShK-modified UCMSCs Inhibit M1-Like Macrophage Polarization and Alleviate Osteoarthritis Progression via PI3K/Akt Axis

The potassium channel Kv1.3 plays an important role in regulating immune cell functions in many inflammatory diseases whereas rarely in osteoarthritis (OA). Here, it is demonstrated that the Kv1.3 of macrophages is upregulated in response to LPS stimulation, as well as in human OA synovium samples than non-OA. Administration of Stichodactyla toxin (ShK), a Kv1.3 blocker, significantly inhibited cartilage degeneration and synovial inflammation in animal models of OA in vivo by inhibiting M1 macrophage polarization and reducing the production of inflammatory factors. In this study, a transgenically engineered human umbilical cord mesenchymal stem cell (UCMSC) delivery system is developed that secreted a peptide ShK, a Kv1.3 potassium blocker, into the knee articular cavity. Collectively, the results identified Kv1.3 as a potential therapeutic target for OA and demonstrated the efficacy of using ShK transgenic engineered UCMSCs as a delivery for the peptide in OA treatment.

Sustained therapeutic effects of self-assembled hyaluronic acid nanoparticles loaded with α-Ketoglutarate in various osteoarthritis stages

Osteoarthritis (OA) is a prevalent degenerative disease characterized by irreversible destruction of articular cartilage, for which no current drugs are known to modify its progression. While intra-articular (IA) injections of hyaluronic acid (HA) offer temporary relief, their effectiveness and long-term benefits are debated. Alpha-ketoglutarate (αKG) has potential chondroprotective properties, but its use is limited by a short half-life and poor cartilage-targeting efficiency. Here, we developed self-assembled HA-αKG nanoparticles (NPs) to combine the benefits of both HA and αKG, showing stability, bioavailability, and sustained pH-responsive release in the knee joint. In both early and advanced OA stages in mice, HA, αKG, and HA-αKG NPs could relieve pain, enhance mobility, and reduce cartilage damage, with HA-αKG NPs demonstrating the best efficacy. Mechanistically, αKG not only promotes cartilage matrix synthesis but also inhibits degradation by activating the PERK-ATF4 signaling pathway to reduce endoplasmic reticulum stress (ERS) in chondrocytes. This study highlights the therapeutic potential of HA-αKG NPs for treating various OA stages, with efficient and sustained effects, suggesting rapid clinical adoption and high acceptability among clinicians and patients.

Prediction of risk for isolated incomplete lateral meniscal injury using a dynamic nomogram based on MRI-derived anatomic radiomics and physical activity: a proof-of-concept study in 3PM-guided management

Background

The 3PM framework revolutionizes disease management by facilitating early risk prediction, disease prevention, and personalized treatment. For isolated incomplete lateral meniscal injuries (IILMI), where early diagnosis is challenging due to non-specific symptoms, 3PM's proactive approach is beneficial in preventing knee joint disease progression and maintaining patients' quality of life.

Aims

This study aimed to develop a predictive model within the 3PM framework, integrating knee MRI anatomical features with individual physical activity (PA) patterns to enhance early IILMI detection and treatment efficacy, improving patient outcomes and quality of life.

Methods

The training dataset comprised 254 patients. Using logistic regression analyses and least absolute shrinkage and selection operator (LASSO), IILMI was identified among various preoperative factors containing knee MRI and PA features. A dynamic nomogram was constructed and subjected to internal and external validations (91 patients). Validation encompassed C-index, receiver operating characteristic (ROC) curves, calibration curves, decision curve analysis (DCA), and clinical impact curves. ROC analysis determined the risk stratification cut-off.

Results

Six independent IILMI factors were identified, including PA intensity, PA type, degree of PA intensity, and MRI-derived anatomical parameters. The dynamic nomogram showed high predictive accuracy (C-index, 0.829 in training, 0.906 in validation). IILMI patients were divided into low-risk, medium-risk, and high-risk groups according to the cut-off value.

Conclusion

In 3PM-guided management, the dynamic nomogram enables early IILMI diagnosis in patients while promoting IILMI stratification making personalized treatment feasible. With further development, it holds promise for effectively predicting IILMI risk, preventing severe knee pathologies, and enhancing the quality of life for at-risk patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-025-00399-3.

Safety and preliminary efficacy of transcutaneous auricular vagus nerve stimulation on chronic knee pain: A pilot trial

Objective

Transcutaneous auricular vagus nerve stimulation (tVNS) may be an innovative treatment for symptoms of knee osteoarthritis (OA) due to possible shared pathological mechanisms between diminished parasympathetic function, central pain mechanisms, and knee pain. Thus, we sought to test the safety and preliminary efficacy of tVNS in people with knee OA.

Design

A pilot trial in which participants received a 60-min tVNS was conducted. At baseline, immediately after, and 15 ​min after tVNS, we assessed knee pain, pressure pain threshold (PPT), temporal summation (TS), conditioned pain modulation (CPM), and high-frequency power of heart rate variability (HF). We examined the extent to which these outcome measures changed after tVNS using linear mixed models.

Results

30 participants with knee OA were included, and all completed the intervention without any major side effects. Compared to baseline, knee pain was reduced by 1.27 (95 ​% CI, -1.74, -0.80) immediately after and by 1.87 (-2.33, -1.40) 15 ​min after tVNS; CPM improved by 0.11 (0.04, 0.19) and 0.07 (-0.01, 0.15); and HF improved by 213.29 (-0.38, 426.96) and 234.17 (20.49, 447.84). PPT and TS were not changed after tVNS.

Conclusions

Our preliminary data demonstrated that tVNS may be a safe pain-relieving treatment for people with knee OA. Our findings suggest that improvement of knee pain might be derived from improvement of parasympathetic function and central pain mechanisms as no local therapy was applied. A large study is needed to confirm that tVNS is a novel intervention to ameliorate knee pain in people with knee OA.

Clinical Trial

ClinicalTrials.gov (NCT05625178).

Antidepressants to Manage Osteoarthritic Pain: The Value of Pain Phenotyping

Osteoarthritis (OA) is a chronic condition in which pain significantly affects quality of life, often leading to reduced physical activity and disability. Globally, an estimated 595 million people are affected, with the numbers likely to increase owing to an aging population and rising obesity rates. Effective pain management is crucial, yet current treatments, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids, often provide limited relief and come with risks. One reason for this limited success is the insufficient recognition of the importance of psychosocial factors and heterogeneity of patients with OA (such as anxiety and depression), which can exacerbate pain and its impacts. The variability in patient pain experiences highlights the potential value of pain phenotyping, which involves a comprehensive assessment of pain characteristics to tailor treatments to individual needs. Antidepressants, particularly serotonin-norepinephrine reuptake inhibitors (SNRIs), show promise in alleviating both psychological symptoms and OA-related pain, but their effectiveness varies among individuals. Therefore, further research into standardized pain phenotyping methods and their integration into antidepressant treatment is needed to improve efficacy and minimize side effects through more personalized approaches.

A Study on the Effects of Gluteal Muscle Activation on the Electromyography of Lower Limb Muscles in Young Male Patients With Patellofemoral Pain Syndrome

OBJECTIVE

Patellofemoral pain syndrome (PFPS) is a common knee issue, and hip joint function significantly affects knee health. Gluteus activation exercises are a promising treatment for PFPS. This study aims to investigate the impact of gluteal muscle activation exercises on the muscle involvement and movement patterns of young male patients with PFPS.

METHODS

Our study was a randomized controlled clinical trial study from June 2020 to December 2021, included 18 young male patients with PFPS, randomly divided into two groups: the gluteus activation group (GAG) and control group (CON), with nine cases in each group. The GAG underwent gluteal muscle activation exercises for 40 min per session, three times per week, for 6 weeks; the CON received no intervention. At baseline and after 6 weeks, the integrated electromyography (IEMG), contribution rates (CRs), and activation times (ATs) of the gluteus maximus (GM), vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and semitendinosus (ST) muscles of the affected lower limb during stair-climbing exercise were assessed. Additionally, the explosive power (EP) of the lower limbs and the visual analog scale (VAS) pain value of the knee joint were evaluated. Paired sample t-tests and independent sample t-tests were used to compare the differences within and between groups.

RESULTS

After 6 weeks, the GAG showed a significant increase in the IEMG of GM by 118 ± 67.09 μVs compared to CON (p < 0.05), and an increase in the CR of the GM by 6.75% (p < 0.05). Additionally, the AT of the GM and BF was significantly reduced (p < 0.05), and the lower limb EP increased by 14.66% compared to the CON (p < 0.05). Concurrently, there was a very significant reduction in the knee VAS pain score (p < 0.01). The CON exhibited no significant changes in the EMG indices of the lower limbs, EP, and VAS before and after the 6 weeks (p > 0.05).

CONCLUSION

A 6-week gluteal muscle activation training program for patients with PFPS can adjust and optimize the IEMG, CR, and firing order of the lower limb muscle groups, enhance EP, and alleviate pain.

Association between serum high-sensitivity C-reactive protein levels and osteoarthritis in adults from NHANES 2015 to 2018

To explore the association between serum high-sensitivity C-reactive protein (HSCRP) levels and osteoarthritis (OA) in adults, providing new evidence for the diagnosis of adult OA. We selected data from the 2015-2018 National Health and Nutrition Examination Survey (NHANES) and conducted a cross-sectional study. Serum HSCRP levels were extracted from laboratory data, and OA patients were identified through questionnaire responses. Participants under the age of 20 and those with incomplete data were excluded. We used multivariable logistic regression models, restricted cubic spline (RCS) functions, and stratified analyses to study the association between serum HSCRP levels and osteoarthritis in adults. After screening, a total of 9,948 participants were included, among whom 1,196 were osteoarthritis patients, representing a prevalence rate of 12.02%. Multivariable logistic regression analysis, along with three adjusted models, showed a positive correlation between serum HSCRP levels and the occurrence of osteoarthritis in adults. Compared to the lowest HSCRP quartile, the highest quartile showed a 1.86-fold higher prevalence of OA (95% confidence interval: 1.55 ~ 2.23, P < 0.001). The restricted cubic spline analysis showed a significant increase in OA incidence with rising serum HSCRP levels (P < 0.05). Subgroup and forest plot analyses indicated a positive correlation between HSCRP levels and osteoarthritis across different subgroups, such as age, gender, hypertension status, activity status, drinking status, and Smoke status (P < 0.05). There is a positive correlation between serum HSCRP levels and the occurrence of osteoarthritis in adults. When a patient's serum HSCRP level is elevated, the possibility of osteoarthritis should be considered.

Mechanisms of blood flow restriction training for knee pain: a mini review

Knee pain, affecting an estimated 654 million people worldwide, so blood flow restriction training (BFRT) is catching the spotlight as an effective intervention. Evidence continues to demonstrate the effectiveness of BFRT in managing knee pain. However, the mechanism by which BFRT alleviates knee pain remains unclear, thereby limiting its application in clinical pain management. This study aims to elucidate the underlying mechanisms of BFRT to better understand its efficacy in treating knee pain. This review will discuss the influence of muscle hypertrophy, endogenous opioid system, endocannabinoids, inflammation regulation, and conditional pain regulation on BFRT treatment of knee pain. Current studies on BFRT have limitations, such as small sample sizes, relatively low-quality evidence, and lack of mechanistic studies. Therefore, further research on BFRT is needed, particularly high-quality and large-sized randomized controlled trials.

Osteoarthritis

Osteoarthritis is a heterogeneous whole-joint disease that can cause pain and is a leading cause of disability and premature work loss. The predominant disease risk factors - obesity and joint injury - are well recognized and modifiable. A greater understanding of the complex mechanisms, including inflammatory, metabolic and post-traumatic processes, that can lead to disease and of the pathophysiology of pain is helping to delineate mechanistic targets. Currently, management is primarily focused on alleviating the main symptoms of pain and obstructed function through lifestyle interventions such as self-management programmes, education, physical activity, exercise and weight management. However, lack of adherence to known effective osteoarthritis therapeutic strategies also contributes to the high global disease burden. For those who have persistent symptoms that are compromising quality of life and have not responded adequately to core treatments, joint replacement is an option to consider. The burden imparted by the disease causes a substantial impact on individuals affected in terms of quality of life. For society, this disease is a substantial driver of increased health-care costs and underemployment. This Primer highlights advances and controversies in osteoarthritis, drawing key insights from the current evidence base.

The eFEct of an Anti-Inflammatory Diet for Knee oSTeoarthritis (FEAST) Trial: Baseline Characteristics and Relationships With Dietary Inflammatory Index

OBJECTIVE

This study aims to: (i) describe the results of recruitment into the eFfEct of an Anti-inflammatory diet for knee oSTeoarthritis (FEAST) randomized controlled trial (RCT); (ii) report baseline characteristics of randomized participants and compare these with four large international cohorts; and (iii) explore cross-sectional associations between dietary inflammatory index (DII®) scores and baseline clinical characteristics.

METHODS

The FEAST RCT compares an anti-inflammatory dietary programme and standard care low-fat dietary programme for adults aged 45-85 years with knee osteoarthritis (OA). At baseline, participants provided medical history (medical comorbidities, symptomatic musculoskeletal sites), completed questionnaires (demographic characteristics, Knee injury and OA Outcome Score (KOOS)) and a 3-day food diary. Both DII® and energy-adjusted DII (E-DIITM) scores were calculated based on 3-day food diary data and was used to quantify the effect of diet on systemic inflammation. Associations between DII/E-DII and KOOS subscales, symptomatic musculoskeletal sites, and comorbidities was assessed using linear and negative binomial regression.

RESULTS

1121 individuals were screened to identify 182 eligible individuals, from which 144 participants (64% female, 36% male) enrolled, with a mean ± SD age 65 ± 8 years and body mass index 30.3 ± 6.2 kg/m2. Overweight (41%) and obesity (45%) was common. Two-thirds (62%) had ≥1 medical comorbidity, most commonly hypertension (26%). Musculoskeletal pain in sites other than the index knee was reported in 79%, most commonly in the lower back (42%). Mean DII and E-DII scores were 0.58 ± 1.49 and -0.31 ± 1.41, respectively. No associations were found between DII/E-DII and KOOS subscales except for activities of daily living (ADL), number of medical comorbidities and symptomatic MSK sites, and BMI.

CONCLUSION

The FEAST cohort is comparable to other knee OA cohorts, supporting generalizability of the results. Despite a relatively pro-inflammatory diet at baseline, DII/E-DII was not associated with KOOS subscales, number of comorbidities or symptomatic musculoskeletal sites.

'The right advice': a qualitative study examining enablers and barriers to recreational running and beliefs about knee health following knee surgery

OBJECTIVES

To examine the experiences, knowledge and beliefs of recreational runners with a history of knee surgery regarding (i) enablers and barriers to running participation, (ii) the association of running and knee joint health, and (iii) perceived benefits and motivations for running.

METHODS

17 runners (≥3 times/week, ≥10 km/week) with a history of knee surgery (7±7 years post-surgery, 9 women, age 36±8 years) participated in one-on-one semi-structured interviews. Interviews were recorded, transcribed verbatim and analysed using reflexive thematic analysis. Trustworthiness was built by following established qualitative research guidelines and by participant validation of findings in the final analysis stages.

RESULTS

We identified 9 themes (5 subthemes) for aim (i); 3 themes (10 subthemes) for aim (ii); and 2 themes (4 subthemes) for aim (iii). Positive health professional support including education, exercise rehabilitation and a tailored return-to-run plan enabled participants to return to running following surgery. Effective load management either independently or with coach assistance, and consistent strength training were considered key to maintaining participation. Barriers to running following surgery included unhelpful health professional encounters, persistent knee symptoms and muscle weakness, new running-related injuries, anxiety and fear about reinjury, and difficulty finding time. Participants had varying beliefs about running and knee joint health, although most believed that running benefited long-term knee health. Improved mental health and social connection were the most common motivators to run.

CONCLUSION

Our qualitative findings may inform strategies to support adults to commence, or return to, and maintain running participation following knee surgery.

An Innovative Anoikis Signature With Inflammatory Infiltrates in Osteoarthritis

AIM

To explore the relationship between an innovative anoikis-related gene signature and inflammatory infiltrates in patients with osteoarthritis.

METHODS

Gene expression profiles (GSM1248759 and GSE200843) were curated from the Gene Expression Omnibus database, followed by the construction of a protein-protein interaction network. Functional and genomic enrichment analyses were conducted using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The CIBERSORT method was employed to investigate immune cell infiltration differences between osteoarthritic and control tissues. Additionally, the ConsensusClusterPlus package in R software was utilized to identify distinct anoikis patterns (Cluster C1 and Cluster C2) and conduct molecular biological investigations.

RESULTS

Analysis revealed two distinct anoikis patterns (Cluster C1 and Cluster C2), with Cluster C2 patients exhibiting varying immune cell levels compared to Cluster C1 patients. Molecular investigations identified 84 DEGs enriched in specific pathways such as adipocytokine signaling, cytokine-cytokine receptor interaction, ECM-receptor interaction, and the PPAR signaling pathway. qPCR experiments confirmed the elevated expression levels of specific genes, including SOD2, MAPK14, CEACM3, LAMB3, COL13A1, TLR3, NOTCH3, and KLF12, in the IL-1β-induced group compared with the osteoarthritis group.

CONCLUSION

This study highlights the role of anoikis-related genes and immune infiltration differences in osteoarthritis, enhancing our understanding of its development.

Lateral Meniscus Repairs Using Single Posteromedial Portal by All-Inside Suture-From Posterior to Anterior

The meniscus plays an important role in absorbing shock, sharing load, reducing contact stress, and maintaining stability of knee joint movement. We know that there are various ways to repair meniscus injuries under arthroscopy. However, we found some technical limitations during the operation, such as the risk of neurovascular injury and the long operation time of repair. On this basis, we modified the lateral meniscus suture technique. A special technique of lateral meniscus repairs using a single posteromedial portal by all-inside suture is proposed: from posterior to anterior, we believe that this technique can effectively optimize the surgical procedure and reduce the time of repair surgery resulting from angle problems, and the use of this method can effectively reduce the possibility of damage to the nerves, blood vessels, and tendons in the knee joint. Surgeons who are initially exposed to arthroscopic repair of the lateral meniscus can use this repair method, which reduces the surgical threshold for the suture of the lateral meniscus.

Characterization of rectus femoris lesions in knee osteoarthritis at different stages and the effect of ultrasound-guided acupotomy

Introduction

Chronic injury to the rectus femoris muscle induces and exacerbates the progression of knee osteoarthritis (KOA). However, the lesion characteristics of the rectus femoris muscle in KOA at different stages have not been fully characterized. The aim of this study was to analyze the pattern of lesion characteristics of the rectus femoris muscle at different stages of KOA and to investigate the mechanism by which ultrasound-guided acupotomy operations can prevent and control KOA.

Methods

Early, middle, and late-stage rabbit KOA models were constructed using the modified Videman method. Ultrasonography was used to record the elastic modulus and cross-sectional area of the rectus femoris muscle, and morphology was used to observe the ultramicroscopic changes in the rectus femoris muscle and assess the degree of fibrosis. Additionally, ultrasound-guided acupotomy operations were performed on the rabbit model of late-stage KOA, and alterations in the key molecular markers of rectus femoris fibrosis were determined using Western Blot and qPCR methods.

Results

As the disease progressed, the elastic modulus of the rectus femoris muscle in KOA rabbits gradually increased, the cross-sectional area gradually decreased, and the degree of fibrosis increased. In contrast, the degree of fibrosis in the rectus femoris muscle improved after ultrasound-guided acupotomy intervention.

Conclusion

These findings highlight the gradual increase in the modulus of elasticity, the gradual decrease in cross-sectional area, and the increased fibrosis of the rectus femoris muscle in KOA rabbits as the disease progressed. Ultrasoundguided acupotomy operations have been shown to have a protective effect on KOA cartilage and to delay the progression of KOA by ameliorating pathological changes in the rectus femoris muscle. The mechanism may involve reducing chronic injury to the rectus femoris muscle and protecting joint homeostasis by attenuating the degree of rectus femoris fibrosis.

TGF-β2 enhances nanoscale cortex stiffness via condensation of cytoskeleton-focal adhesion plaque

Physical spatiotemporal characteristics of cellular cortex dominate cell functions and even determine cell fate. The cellular cortex is able to reorganize to a dynamic steady status with changed stiffnesses once stimulated, and thus alter the physiological and pathological activities of almost all types of cells. TGF-β2, a potent pleiotropic growth factor, plays important roles in cartilage development, endochondral ossification, and cartilage diseases. However, it is not yet known whether TGF-β2 would alter the physical spatiotemporal characteristics of the cell cortex such as cortex stiffness, thereby affecting the function of chondrocytes. In this study, we investigated the influence of TGF-β2 on cellular cortex stiffness of chondrocytes and the underlying mechanism. We firstly detected TGF-β2-induced changes in cytoskeleton and focal adhesion plaque, which were closely related to cellular cortex stiffness. We then characterized the landscape of nanoscale cortex stiffness in individual chondrocytes induced by TGF-β2 via atomic force microscopy. By using inhibitors, latrunculin A and blebbistatin, we verified the importance of cytoskeleton-focal adhesion plaque axis on cellular cortex stiffness of chondrocytes induced by TGF-β2. We finally elucidated that TGF-β2 enhanced the phosphorylation of Smad3 and facilitated the nuclear accumulation of p-Smad3. The p-Smad3 aggregated in the nuclei enhanced the cytoskeleton and focal adhesion plaque at transcriptional level, thereby mediating changes in cell cortex stiffness. Taken together, these results provide an understanding about the role of TGF-β2 on physical spatiotemporal properties of cell cortex in chondrocytes, and might provide cues for interpretation of cartilage development and interventions to cartilage diseases.

Effects of functional strength training on pain, function, and lower extremity biomechanics in patients with patellofemoral pain syndrome: a randomized clinical trial

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a common disorder affecting the lower extremity. This study aimed to compare the effects of functional strength training (FST) and standard strength training (SST) in PFPS patients.

METHODS

Forty college students (aged 18-30 years) with PFPS and no exercise habits were randomized into FST group (n = 20) and SST group (n = 20). FST group underwent six weeks of lower extremity training focused on functional adaptations, whereas SST group focus on lower extremity strength training. Function (Kujala Patellofemoral Scale, KPS), pain (visual analog scale, VAS), peak joint angles of hip, knee, and ankle, along with muscle activation (step-down test) of Vastus medialis, Vastus lateralis, Biceps femoris, Semitendinosus, Gluteus maximus, and Gluteus medius were assessed at baseline and after intervention.

RESULTS

FST outperformed SST in pain reduction (p = 0.026) and function (p = 0.006) post-intervention. The FST group also showed increased hip flexion (p < 0.001), gluteus maximus activation (p < 0.001), and reduced knee valgus (p = 0.032), while SST group exhibited greater knee flexion (p = 0.008), and higher activation of the lateral femoral (p < 0.001) and semitendinosus (p < 0.001).

CONCLUSION

Interventions focused on functional adaptations result in differential kinematic and muscle activation changes that may result in greater improvements in pain and knee function than lower limb muscle strengthening alone.

TRIAL REGISTRATION

chictr.org.cn. NO: ChiCTR2400087664. Date 01/08/2024.

Fasting activates optineurin-mediated mitophagy in chondrocytes to protect against osteoarthritis

Mitochondrial homeostasis plays a crucial role in the pathogenesis of osteoarthritis (OA), a chronic musculoskeletal disorder characterized by articular cartilage degeneration and chondrocyte apoptosis. However, molecular mechanisms underlying the association between mitophagy and OA remain unclear. Here, we aimed to investigate the role of the autophagy receptor protein optineurin (OPTN) in OA, and explore the effects of dietary intervention on OA symptoms and its relationship with OPTN-mediated mitophagy. Our findings showed the downregulation of OPTN in patients with OA. Using an Optn-knockout mouse model, we demonstrated that OPTN deficiency leads to impaired mitophagy, resulting in the accumulation of damaged mitochondria, increased production of reactive oxygen species, and chondrocyte apoptosis. Furthermore, fasting prevented OA progression by activating OPTN-mediated mitophagy and maintaining mitochondrial homeostasis in mice. The present study revealed a novel mechanism by which OPTN-mediated mitophagy influences chondrocytes and the OA phenotype in Optn-knockout mice, suggesting that OPTN-mediated mitophagy plays a crucial role in OA development and progression. This study provides new insights into the pathogenesis of OA and offers a potential avenue for the development of novel drugs targeting OPTN to mitigate OA progression.

NLRP3 Inflammasome-Mediated Osteoarthritis: The Role of Epigenetics

The prevalence of osteoarthritis (OA) notably surges with age and weight gain. The most common clinical therapeutic drugs are painkillers, yet they cannot impede the deteriorating course of OA. Thus, understanding OA's pathogenesis and devising effective therapies is crucial. It is generally recognized that inflammation, pyroptosis, and OA progression are tightly linked. The activation of NLRP3 inflammasome can lead to the discharge of the pro-inflammatory cytokines Interleukin-1β and IL-18, intensifying subsequent inflammatory reactions and promoting OA development. Conversely, the imbalance caused by deacetylase-regulated NLRP3 inflammasome underlies the chronic mild inflammation related to degenerative diseases. Therefore, this article expounds on the mechanism of OA pathogenesis and the role of histone deacetylases (HDACs) in NLRP3 inflammasome-triggered OA, and illustrates the application of HDAC inhibitors in OA, striving to provide more insights into novel OA treatment approaches.

Acute effects of tissue flossing on boxers with chronic knee pain

Objectives

To explore the acute intervention effects of tissue flossing on chronic knee pain (CKP) in boxers.

Methods

Eighteen boxers with CKP (12 male/6 female) were randomly divided into an experimental group (EG) with tissue flossing (n = 9) and a control group (CG) (n = 9). The visual analog scale (VAS), Lysholm knee function score, flexion range of motion (ROM), maximal isometric extensor muscle strength, and stability of the knee were measured pre- and post-intervention (EG: 3-minute tissue flossing, CG: rest).

Results

VAS (F = 15.849, p = 0.001, η 2 p = 0.498) and Lysholm knee function (F = 9.327, p = 0.008, η 2 p = 0.357) significantly improved more in the EG than in the CG. There was a significant difference for maximal isometric extensor muscle strength (F = 17.769, p = 0.001, η 2 p = 0.542) and knee stability (F = 13.844, p = 0.002, η 2 p = 0.464) but no significant difference for ROM (F = 1.218, p = 0.287, η 2 p = 0.075) between the EG and CG.

Conclusion

Tissue flossing can reduce knee pain, improve knee function, increase knee extensor strength, and improve knee stability in boxers with CKP.

Noisy knees - knee crepitus prevalence and association with structural pathology: a systematic review and meta-analysis

OBJECTIVE

Knee crepitus, the audible crackling or grinding noise during knee movement, can be experienced across the lifespan and create concern for underlying pathology. Our systematic review aims to provide a summary estimate of knee crepitus prevalence and its association with structural pathology among the general population and across knee conditions.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, CENTRAL, Web of Science, SPORTDiscus and CINAHL.

ELIGIBILITY CRITERIA

Studies evaluating knee crepitus prevalence.

RESULTS

103 studies involving 36 439 participants (42 816 knees) were included. Based on very low certainty evidence, the pooled prevalence of knee crepitus in the general population was 41% (7609 knees; 95% CI 36% to 45%; I2=92.6%); in pain-free persons 36% (852 knees; 95% CI 23% to 50%; I2=91.9%), and in those with osteoarthritis (OA) 81% (18 821 knees; 95% CI 75% to 87%; I2=97.9%). Across other musculoskeletal knee conditions, the pooled prevalence of knee crepitus ranged from 35% (ligament injury; 2740 knees; 95% CI 27% to 44%; I2=95.6%) to 61% (cartilage pathology; 1445 knees; 95% CI 40% to 81%; I2=98.2%). There was low to very low certainty evidence of an association between knee crepitus and radiographic OA (OR 3.79, 95% CI 1.99 to 7.24; 1725 knees; I2=53.0%) and several OA-related features on magnetic resonance imaging (MRI).

CONCLUSION

In this review, knee crepitus was prevalent in the general population, pain-free persons, those with knee OA and other musculoskeletal knee conditions. Knee crepitus was associated with a more than threefold increased odds of radiographic OA diagnosis and several OA-related MRI features. The low to very low certainty of evidence informing our aggregated prevalence estimates and association outcomes suggest that results should be interpreted with caution.

Musculoskeletal Organs-on-Chips: An Emerging Platform for Studying the Nanotechnology-Biology Interface

Nanotechnology-based approaches are promising for the treatment of musculoskeletal (MSK) disorders, which present significant clinical burdens and challenges, but their clinical translation requires a deep understanding of the complex interplay between nanotechnology and MSK biology. Organ-on-a-chip (OoC) systems have emerged as an innovative and versatile microphysiological platform to replicate the dynamics of tissue microenvironment for studying nanotechnology-biology interactions. This review first covers recent advances and applications of MSK OoCs and their ability to mimic the biophysical and biochemical stimuli encountered by MSK tissues. Next, by integrating nanotechnology into MSK OoCs, cellular responses and tissue behaviors may be investigated by precisely controlling and manipulating the nanoscale environment. Analysis of MSK disease mechanisms, particularly bone, joint, and muscle tissue degeneration, and drug screening and development of personalized medicine may be greatly facilitated using MSK OoCs. Finally, future challenges and directions are outlined for the field, including advanced sensing technologies, integration of immune-active components, and enhancement of biomimetic functionality. By highlighting the emerging applications of MSK OoCs, this review aims to advance the understanding of the intricate nanotechnology-MSK biology interface and its significance in MSK disease management, and the development of innovative and personalized therapeutic and interventional strategies.

Therapeutic Controlled Release Strategies for Human Osteoarthritis

Osteoarthritis is a progressive, irreversible debilitating whole joint disease that affects millions of people worldwide. Despite the availability of various options (non-pharmacological and pharmacological treatments and therapy, orthobiologics, and surgical interventions), none of them can definitively cure osteoarthritis in patients. Strategies based on the controlled release of therapeutic compounds via biocompatible materials may provide powerful tools to enhance the spatiotemporal delivery, expression, and activities of the candidate agents as a means to durably manage the pathological progression of osteoarthritis in the affected joints upon convenient intra-articular (injectable) delivery while reducing their clearance, dissemination, or side effects. The goal of this review is to describe the current knowledge and advancements of controlled release to treat osteoarthritis, from basic principles to applications in vivo using therapeutic recombinant molecules and drugs and more innovatively gene sequences, providing a degree of confidence to manage the disease in patients in a close future.

Targeted lipid nanoparticles distributed in hydrogel treat osteoarthritis by modulating cholesterol metabolism and promoting endogenous cartilage regeneration

Osteoarthritis (OA) is the most common disease in aging joints and has characteristics of cartilage destruction and inflammation. It is currently considered a metabolic disease, and the CH25H-CYP7B1-RORα axis of cholesterol metabolism in chondrocytes plays a crucial catabolic regulatory role in its pathogenesis. Targeting of this axis in chondrocytes may provide a therapeutic approach for OA treatment. Here, in this study, we propose to use a combination of stem cell-recruiting hydrogels and lipid nanoparticles (LNPs) that modulate cholesterol metabolism to jointly promote a regenerative microenvironment. Specifically, we first developed an injectable, bioactive hydrogel composed of self-assembling peptide nanofibers that recruits endogenous synovial stem cells (SMSCs) and promotes their chondrogenic differentiation. At the same time, LNPs that regulate cholesterol metabolism are incorporated into the hydrogel and slowly released, thereby improving the inflammatory environment of OA. Enhancements were noted in the inflammatory conditions associated with OA, alongside the successful attraction of mesenchymal stem cells (MSCs) from the synovial membrane. These cells were then observed to differentiate into chondrocytes, contributing to effective cartilage restoration and chondrocyte regeneration, thereby offering a promising approach for OA treatment. In summary, this approach provides a feasible siRNA-based therapeutic option, offering a potential nonsurgical solution for treatment of OA.

Comparison of the effects of high tibial osteotomy with and without a tourniquet

BACKGROUND

Tourniquets are routinely employed to achieve hemostasis in modern limb surgeries. Nevertheless, the precise role and benefits of tourniquets in high tibial osteotomy (HTO) surgeries remain understudied. The aim of this study was to assess the application of tourniquets in high-tibial osteotomy procedures.

METHODS

This was a prospective study of patients who underwent HTO surgery at an identical hospital. The participants were randomly assigned into two groups: Group A, with a tourniquet (n = 43); and Group B, without a tourniquet (n = 43). The same surgical technique and postoperative care were employed for both groups of patients. Knee range of motion (ROM) and pain were assessed by utilizing a visual analogue scale (VAS) after exercise and maximum calf circumference, and postoperative Hospital for Special Surgery (HSS) score, as well as inflammatory markers including CRP and IL-6, were adopted to compare and analyse the recovery of knee function in the two groups of patients following surgery.

RESULTS

All participants were followed up for a period exceeding three months. No cases of vascular or nerve injuries were observed during surgery in either group. Moreover, there was no statistically significant difference in total blood loss volume throughout treatment or haemoglobin or haematocrit levels (P > 0.05). furthermore, Group A underwent a shorter operation than Group B did (P < 0.05). Group B demonstrated decreased postoperative visual analog scale (VAS) pain levels, calf swelling (P < 0.05), increased early knee range of motion (P < 0.05), and diminished release of blood inflammation markers(IL-6 and CRP) (P < 0.05).

CONCLUSION

The application of tourniquets in HTO surgery reduces intraoperative blood loss and shortens the operative time yet does not substantially affect total bleeding. Nonetheless, the absence of a tourniquet resulted in reduced postoperative pain and facilitated early rehabilitation of knee function.

Patellar Non-Traumatic Pathologies: A Pictorial Review of Radiologic Findings

Patellar pathologies are a common cause of knee dysfunction, with Patellofemoral Pain Syndrome (PFPS) alone responsible for 25% of knee-related visits to sports medicine clinics. Non-traumatic conditions, while often overlooked, can also lead to significant discomfort and functional limitations, highlighting the importance of accurate and timely diagnosis for effective management and prevention of complications. This pictorial review examines the radiologic characteristics of various non-traumatic patellar disorders, focusing on imaging modalities such as radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Key diagnostic markers, including patellar tilt, tibial tuberosity-trochlear groove distance (TT-TG), and congruence angle (CA), are discussed for their significance in non-traumatic pathology identification. Furthermore, this review highlights specific radiologic features for a range of non-traumatic patellar conditions, including patellar tendinopathy, chondromalacia patellae, and trochlear dysplasia, emphasizing how distinct radiologic findings facilitate precise diagnosis and clinical assessment. Ultimately, it provides a practical guide for clinicians in diagnosing non-traumatic patellar pathologies through a comprehensive review of key radiologic features while also discussing advancements in imaging technologies and management strategies to support accurate diagnosis and effective clinical decision-making.