Tackling obesity in knee osteoarthritis

Selective STAT3 inhibitor STX-0119 alleviates osteoarthritis progression by modulating the STAT3/PPARγ signaling pathway

Osteoarthritis (OA), characterized by chronic pain, significantly affects the quality of life of affected individuals. Key factors in OA pathogenesis include cartilage degradation and inflammation. Signal transducer and activator of transcription 3 (STAT3), a member of the STAT protein family, plays a pivotal role in mediating inflammation. STX-0119 has been verified as a small molecular compound that can specifically inhibit STAT3. However, the efficacy of STX-0119 in the treatment of OA remains to be evaluated. Therefore, the aim of this study was to explore the therapeutic effects and molecular mechanisms of STX-0119 in the treatment of OA. We found that the expression of phosphorylated STAT3 is upregulated in human OA cartilage as well as in the cartilage of a mouse model of OA. In vivo, joint injection of STX-0119 into OA mice alleviated cartilage degeneration without affecting the subchondral bone. Additionally, STX-0119 could inhibit the phosphorylation of STAT3 in the cartilage. In vitro, STX-0119 suppressed inflammatory responses in chondrocytes and promoted anabolic metabolism in an interleukin-1β-induced chondrocyte inflammation model. Additionally, the results of transcriptome sequencing and lentiviral infection assays demonstrated that in chondrocytes, STX-0119 induces the upregulation of peroxisome proliferators-activated receptor gamma (PPARγ) expression by inhibiting STAT3 phosphorylation. Finally, in ex vivo cultures of human cartilage samples, STX-0119 was reaffirmed to inhibit cartilage degeneration via the STAT3/PPARγ signaling pathway. Together, our findings support the potential of STX-0119 for development as a therapeutic agent targeting STAT3 for the treatment of OA.

The role of obesity and adipose tissue dysfunction in osteoarthritis pain

Obesity has a pivotal and multifaceted role in pain associated with osteoarthritis (OA), extending beyond the mechanistic influence of BMI. It exerts its effects both directly and indirectly through various modifiable risk factors associated with OA-related pain. Adipose tissue dysfunction is highly involved in OA-related pain through local and systemic inflammation, immune dysfunction, and the production of pro-inflammatory cytokines and adipokines. Adipose tissue dysfunction is intricately connected with metabolic syndrome, which independently exerts specific effects on OA-related pain, distinct from its association with BMI. The interplay among obesity, adipose tissue dysfunction and metabolic syndrome influences OA-related pain through diverse pain mechanisms, including nociceptive pain, peripheral sensitization and central sensitization. These complex interactions contribute to the heightened pain experience observed in individuals with OA and obesity. In addition, pain management strategies are less efficient in individuals with obesity. Importantly, therapeutic interventions targeting obesity and metabolic syndrome hold promise in managing OA-related pain. A deeper understanding of the intricate relationship between obesity, metabolic syndrome and OA-related pain is crucial and could have important implications for improving pain management and developing innovative therapeutic options in OA.

The dual amylin and calcitonin receptor agonist KBP-336 elicits a unique combination of weight loss, antinociception and bone protection - a novel disease-modifying osteoarthritis drug

BACKGROUND

Despite the extensive research to provide a disease-modifying osteoarthritis drug (DMOAD), there is still no approved DMOAD. Dual amylin and calcitonin receptor agonists (DACRA) can provide metabolic benefits along with antinociceptive and potential structural preserving effects. In these studies, we tested a DACRA named KBP-336 on a metabolic model of OA in meniscectomised (MNX) rats.

METHODS

We evaluated KBP-336's effect on pain-like symptoms in Sprague Dawley (SD) rats on high-fat diet (HFD) that underwent meniscectomy using the von Frey test to measure the 50% paw withdrawal threshold (PWT) and analyzed using one-way ANOVA. Short in vivo studies and in vitro cell receptor expression systems were used to illustrate receptor pharmacology.

RESULTS

After 30 weeks on HFD, including an 8-week treatment, female MNX animals receiving KBP-336 4.5 nmol/Kg/72 h had lower body weight and smaller adipose tissues than their vehicle-treated counterparts. After 20 weeks on HFD, including an 8-week treatment, male rats receiving KBP-336 had lower body weight than the vehicle group. In both the female and male rats, the MNX groups on KBP-336 treatment had a higher PWT than the vehicle-treated MNX group. Aiming to identify the receptor influencing pain alleviation, KBP-336 was compared to the long-acting human calcitonin (hCTA). Single-dose studies on 12-week-old male rats showed that hCTA lowers CTX-I without affecting food intake, confirming its calcitonin receptor selectivity. On the metabolic OA model with 18 weeks of HFD, including 6-week treatment, hCTA at 100 nmol/Kg/24 h and KBP-336 at 0.5, 1.5, and 4.5 nmol/Kg/72 h produced significantly higher PWT in MNX animals compared to MNX animals on vehicle treatment. hCTA and KBP-336 at 0.5 nmol/Kg did not affect body weight and fat tissues.

CONCLUSION

Overall, KBP-336 improved the pain observed in the metabolic OA model. Calcitonin receptor activation proved to be essential in this antinociceptive effect.

Weight Loss Induced by Antiobesity Medications and All-Cause Mortality Among Patients With Knee or Hip Osteoarthritis

OBJECTIVE

The current guidelines recommend weight loss for patients with overweight or obesity and knee or hip osteoarthritis (OA); however, there is a paucity of data on the relation of weight loss to death among patients with OA. We aimed to examine the relation of the rate of weight loss induced by antiobesity medications over one year to all-cause mortality among patients with overweight or obesity and knee or hip OA.

METHODS

Using the IQVIA Medical Research Database, we identified people with overweight or obesity and knee or hip OA. We emulated analyses of a hypothetical target trial to assess the effect of slow-to-moderate (2%-10%) or fast (≥10%) weight loss induced by the initiation of antiobesity medications within one year on all-cause mortality and secondary outcomes over five years' follow-up.

RESULTS

Among 6,524 participants, the five-year all-cause mortality rates were 5.3%, 4.0%, and 5.4% for weight gain or stable, slow-to-moderate weight loss, and fast weight loss arms, respectively. Compared with the weight gain or stable arm, hazard ratios of all-cause mortality were 0.72 (95% confidence interval [CI] 0.56-0.92) for the slow-to-moderate weight loss arm and 0.99 (95% CI 0.67-1.44) for the fast weight loss arm. We found dose-response protective effects of weight loss on incident hypertension, type 2 diabetes, and venous thromboembolism but a slightly higher risk of cardiovascular disease, albeit not statistically significant, in the fast rate of weight loss arm than in the weight gain or stable arm and no significant relations of weight loss to the risk of cancer.

CONCLUSION

In this population-based study, a slow-to-moderate, but not fast, rate of weight loss induced by antiobesity medications is associated with a lower risk of all-cause mortality in people with overweight or obesity and knee or hip OA.

Predictors of postoperative hospital length of stay after total knee arthroplasty

INTRODUCTION

We aimed to collect and analyse clinical and functional variables of patients undergoing rehabilitation after total knee arthroplasty (TKA), to identify the variables that influence the postoperative hospital length of stay (LOS).

METHODS

We conducted a retrospective analysis of prospectively collected data of 1,082 consecutive patients (746 females and 336 males) who underwent primary TKA and rehabilitation in our orthopaedic institute between January 2013 and July 2017. Clinical and anthropometric data were analysed using a multivariate linear regression model.

RESULTS

The average LOS was 5.08 ± 2.52 days in the Department of Orthopaedic Surgery and 12.67 ± 5.54 days in the Sports Rehabilitation Unit. Factors such as age, female sex and the presence of comorbidities were predictive of a longer stay. The presence of caregiver assistance at home was associated with shorter LOS. There was no evidence of a statistically significant positive association between body mass index and LOS.

CONCLUSION

An in-depth and early knowledge of factors that influence LOS may enable the multidisciplinary team to plan a patient-tailored rehabilitation path and better allocate resources to maximise patients' functional recovery, while reducing LOS and the overall cost of the procedure.

Metabolic syndrome increases osteoarthritis risk: findings from the UK Biobank prospective cohort study

OBJECTIVE

The association between Metabolic Syndrome (MetS), its components, and the risk of osteoarthritis (OA) has been a topic of conflicting evidence in different studies. The aim of this present study is to investigate the association between MetS, its components, and the risk of OA using data from the UK Biobank.

METHODS

A prospective cohort study was conducted in the UK Biobank to assess the risk of osteoarthritis (OA) related to MetS. MetS was defined according to the criteria set by the International Diabetes Federation (IDF). Additionally, lifestyle factors, medications, and the inflammatory marker C-reactive protein (CRP) were included in the model. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI). The cumulative risk of OA was analyzed using Kaplan-Meier curves and log-rank tests. To explore potential nonlinear associations between MetS components and OA risk, a restricted cubic splines (RCS) model was employed. In addition, the polygenic risk score (PRS) of OA was calculated to characterize individual genetic risk.

RESULTS

A total of 45,581 cases of OA were identified among 370,311 participants, with a median follow-up time of 12.48 years. The study found that individuals with MetS had a 15% higher risk of developing OA (HR = 1.15, 95%CI:1.12-1.19). Additionally, central obesity was associated with a 58% increased risk of OA (HR = 1.58, 95%CI:1.5-1.66), while hyperglycemia was linked to a 13% higher risk (HR = 1.13, 95%CI:1.1-1.15). Dyslipidemia, specifically in triglycerides (HR = 1.07, 95%CI:1.05-1.09) and high-density lipoprotein (HR = 1.05, 95%CI:1.02-1.07), was also found to be slightly associated with OA risk. When stratified by PRS, those in the high PRS group had a significantly higher risk of OA compared to those with a low PRS, whereas no interaction was found between MetS and PRS on OA risks. Furthermore, the presence of MetS significantly increased the risk of OA by up to 35% in individuals with elevated CRP levels (HR = 1.35, 95% CI:1.3-1.4).

CONCLUSION

MetS and its components have been found to be associated with an increased risk of OA, particularly in individuals with elevated levels of CRP. These findings highlight the significance of managing MetS as a preventive and intervention measure for OA.

Ensemble deep-learning networks for automated osteoarthritis grading in knee X-ray images

The Kellgren-Lawrence (KL) grading system is a scoring system for classifying the severity of knee osteoarthritis using X-ray images, and it is the standard X-ray-based grading system for diagnosing knee osteoarthritis. However, KL grading depends on the clinician's subjective assessment. Moreover, the accuracy varies significantly depending on the clinician's experience and can be particularly low. Therefore, in this study, we developed an ensemble network that can predict a consistent and accurate KL grade for knee osteoarthritis severity using a deep learning approach. We trained individual models on knee X-ray datasets using the most suitable image size for each model in an ensemble network rather than using datasets with a single image size. We then built the ensemble network using these models to overcome the instability of single models and further improve accuracy. We conducted various experiments using a dataset of 8260 images from the Osteoarthritis Initiative open dataset. The proposed ensemble network exhibited the best performance, achieving an accuracy of 76.93% and an F1-score of 0.7665. The Grad-CAM visualization technique was used to further evaluate the focus of the model. The results demonstrated that the proposed ensemble network outperforms existing techniques that have performed well in KL grade classification. Moreover, the proposed model focuses on the joint space around the knee to extract the imaging features required for KL grade classification, revealing its high potential for diagnosing knee osteoarthritis.

Injectable hydrogels: An emerging therapeutic strategy for cartilage regeneration

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

Association of smoking with cartilage loss of knee osteoarthritis: data from two longitudinal cohorts

BACKGROUND

Previous studies have been inconsistent concerning the association between smoking and risk of osteoarthritis (OA). This study aimed to explore the associations of smoking status and change in cartilage volume of OA in two longitudinal cohorts.

METHODS

Subjects from the Osteoarthritis Initiative cohort (OAI, n = 593) and the Tasmanian Older Adult Cohort (TASOAC, n = 394) were included in this study. For both cohorts, participants were classified into three groups based on their smoking status, namely 'never', 'former', and 'current' smokers. The outcome measures were the annual rate of change of tibiofemoral cartilage volume over 2 years in OAI and of tibial cartilage volume over 2.6 years in TASOAC. Potential confounders were balanced using the inverse probability of treatment weighting (IPTW) method.

RESULTS

Overall, 42.3% and 37.4% of participants were former smokers, and 5.7% and 9.3% were current smokers in the OAI and TASOAC cohorts, respectively. Compared to never smokers, neither former nor current smoking was associated with risk of the annual rate of change of tibiofemoral cartilage volume in OAI (former smoker: β=-0.068%/year, 95% confidence interval [CI] -0.824 to 0.688, p = 0.860; current smoker: β=-0.222%/year, 95% CI -0.565 to 0.120, p = 0.204) and tibial cartilage volume in TASOAC (former smoker: β = 0.001%/year, 95% CI -0.986 to 0.989, p = 0.998; current smoker: β=-0.839%/year, 95% CI -2.520 to 0.844, p = 0.329).

CONCLUSIONS

Our findings from two independent cohorts consistently showed that smoking was not associated with knee cartilage loss in older adults.

Leptin and interleukin-1β levels associated with osteoarthritis in Vietnamese patients: a cross-sectional analysis

Leptin and interleukin-1 beta (IL-1β) are two extensively studied biomarkers associated with metabolic syndrome (MetS) and osteoarthritis (OA). Previous studies have mostly focused on either MetS or OA alone, with no available data on Vietnamese patients. This study aimed to investigate the levels of leptin and IL-1β in this patient population and explore their association with clinical parameters of MetS and OA. The study included 164 patients with primary knee OA, who were classified into two categories based on the presence of MetS, and 78 healthy controls. The plasma leptin and IL-1β levels were quantified by ELISA and correlated with clinical parameters. Leptin levels were higher in patients with OA (11.50±10.04 ng/mL) than in healthy controls (0.54±0.37 ng/mL) and increased in patients with MetS compared to those without MetS. IL-1β levels were also significantly higher in OA patients (14.63±15.87 pg/mL) than in controls (7.79±5.11 pg/mL), but were not significantly different between the MetS and non-MetS groups. Leptin levels were positively correlated with body mass index, waist-to-hip ratio, visual analogue scale scores, HbA1c and insulin levels, and HOMA-IR index, whereas IL-1β levels were only correlated with insulin levels and HOMA-IR index. ROC curve analysis revealed that leptin and IL-1β levels could distinguish individuals with and without OA (AUC=0.96; 0.88, respectively), and individuals with and without MetS (AUC=0.82; 0.71, respectively). Our findings suggested that both leptin and IL-1β levels were associated with both MetS and OA and may play a critical role in the pathogenesis of MetS-related OA.

Development of a nomogram prediction model for gait speed trajectories in persons with knee osteoarthritis

To examine heterogeneous trajectories of 8-year gait speed among patients with symptomatic knee osteoarthritis (KOA) and to develop a nomogram prediction model. We analyzed data from the Osteoarthritis Initiative (OAI) assessed at baseline and follow-up over 8 years (n = 1289). Gait speed was measured by the 20-m walk test. The gait speed trajectories among patients with KOA were explored by latent class growth analysis. A nomogram prediction model was created based on multivariable logistic regression. Three gait speed trajectories were identified: the fast gait speed group (30.4%), moderate gait speed group (50.5%) and slow gait speed group (19.1%). Age ≥ 60 years, female, non-white, nonmarried, annual income < $50,000, obesity, depressive symptoms, comorbidity and WOMAC pain score ≥ 5 were risk factors for the slow gait trajectory. The area under the ROC curve of the prediction model was 0.775 (95% CI 0.742-0.808). In the external validation cohort, the AUC was 0.773 (95% CI 0.697-0.848). Heterogeneous trajectories existed in the gait speed of patients with KOA and could be predicted by multiple factors. Risk factors should be earlier identified, and targeted intervention should be carried out to improve physical function of KOA patients.

Inflammatory Process on Knee Osteoarthritis in Cyclists

Osteoarthritis is a disorder affecting the joints and is characterized by cellular stress and degradation of the extracellular matrix cartilage. It begins with the presence of micro- and macro-lesions that fail to repair properly, which can be initiated by multiple factors: genetic, developmental, metabolic, and traumatic. In the case of the knee, osteoarthritis affects the tissues of the diarthrodial joint, manifested by morphological, biochemical, and biomechanical modifications of the cells and the extracellular matrix. All this leads to remodeling, fissuring, ulceration, and loss of articular cartilage, as well as sclerosis of the subchondral bone with the production of osteophytes and subchondral cysts. The symptomatology appears at different time points and is accompanied by pain, deformation, disability, and varying degrees of local inflammation. Repetitive concentric movements, such as while cycling, can produce the microtrauma that leads to osteoarthritis. Aggravation of the gradual lesion in the cartilage matrix can evolve to an irreversible injury. The objective of the present review is to explain the evolution of knee osteoarthritis in cyclists, to show the scarce research performed in this particular field and extract recommendations to propose future therapeutic strategies.

Regulatory mechanism of circular RNA involvement in osteoarthritis

Osteoarthritis (OA) causes joint pain, stiffness, and dysfunction in middle-aged and older adults; however, its pathogenesis remains unclear. Circular RNAs (circRNAs) are differentially expressed in patients with OA and participate in a multigene, multitarget regulatory network. CircRNAs are involved in the development of OA through inflammatory responses, including proliferation, apoptosis, autophagy, differentiation, oxidative stress, and mechanical stress. Most circRNAs are used as intracellular miRNA sponges in chondrocytes, endplate chondrocytes, mesenchymal stem cells, synoviocytes, and macrophages to promote the progression of OA. However, a small portion of circRNAs participates in the pathogenesis of OA by intracellular mechanisms, such as protein binding, methylation, or intercellular exosome pathways. In this sense, circRNAs might serve as potential novel biomarkers and therapeutic targets for OA.

Increased Risk of Concomitant Meniscal Injuries in Adolescents With Elevated Body Mass Index After Anterior Cruciate Ligament Tear: A Systematic Review

PURPOSE

To investigate existing studies examining the association between body mass index (BMI) and outcomes of anterior cruciate ligament reconstruction (ACLR) in adolescent patients.

METHODS

A literature search was conducted on PubMed and Embase. Studies examining associations between BMI and outcomes after ACLR in adolescents were included. Quality assessment was performed. Data on patient age, sex, study design, time of follow-up, sample size, graft type, concomitant injuries (meniscal injury, surgical procedures), clinical outcomes (revision ACLR, postoperative weight gain, post-traumatic osteoarthritis [PTOA], range of motion [ROM]), and functional outcome (muscle strength) were extracted.

RESULTS

Eleven papers of Levels II-IV evidence were included. Five studies found positive correlations between BMI and risk of concomitant meniscal injuries. Two of them reported young patients with elevated BMI having 1.6 times greater odds of requiring meniscectomy (P < .01) and 1.031 times greater odds of requiring concomitant surgeries (P = .011). One study showed significant positive association of postoperative weight gain by time (r = 0.28, P < .01), with smaller increase in the overweight and obese groups compared with the normal-weight group. One study demonstrated greater cartilage breakdown in young patients with overweight and obesity postsurgery, contributing to PTOA (r = 0.42, P = .009). There was no clinically important difference in postoperative ROM and muscle strength. Four studies reviewed the association between BMI and revision ACLR risk, but results were heterogeneous and a firm conclusion cannot be drawn.

CONCLUSIONS

Adolescents with elevated BMI are more likely to have concomitant meniscal injuries and surgical procedures after ACL tear. There is some weak evidence of the association of elevated BMI with PTOA and slight postoperative weight gain post-ACLR. There may not be any clinically significant association of obesity with post-operative muscle strength and ROM, and current studies are inconclusive regarding the impact of BMI on revision ACLR risk.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II-IV studies.

Orang Asli Health and Lifeways Project (OA HeLP): a cross-sectional cohort study protocol

INTRODUCTION

Non-communicable disease (NCD) risk is influenced by environmental factors that are highly variable worldwide, yet prior research has focused mainly on high-income countries where most people are exposed to relatively homogeneous and static environments. Understanding the scope and complexity of environmental influences on NCD risk around the globe requires more data from people living in diverse and changing environments. Our project will investigate the prevalence and environmental causes of NCDs among the indigenous peoples of Peninsular Malaysia, known collectively as the Orang Asli, who are currently undergoing varying degrees of lifestyle and sociocultural changes that are predicted to increase vulnerability to NCDs, particularly metabolic disorders and musculoskeletal degenerative diseases.

METHODS AND ANALYSIS

Biospecimen sampling and screening for a suite of NCDs (eg, cardiovascular disease, type II diabetes, osteoarthritis and osteoporosis), combined with detailed ethnographic work to assess key lifestyle and sociocultural variables (eg, diet, physical activity and wealth), will take place in Orang Asli communities spanning a gradient from remote, traditional villages to acculturated, market-integrated urban areas. Analyses will first test for relationships between environmental variables, NCD risk factors and NCD occurrence to investigate how environmental changes are affecting NCD susceptibility among the Orang Asli. Second, we will examine potential molecular and physiological mechanisms (eg, epigenetics and systemic inflammation) that mediate environmental effects on health. Third, we will identify intrinsic (eg, age and sex) and extrinsic (eg, early-life experiences) factors that predispose certain people to NCDs in the face of environmental change to better understand which Orang Asli are at greatest risk of NCDs.

ETHICS AND DISSEMINATION

Approval was obtained from multiple ethical review boards including the Malaysian Ministry of Health. This study follows established principles for ethical biomedical research among vulnerable indigenous communities, including fostering collaboration, building cultural competency, enhancing transparency, supporting capacity building and disseminating research findings.

Risk factors of cartilage lesion after anterior cruciate ligament reconstruction

Anterior cruciate ligament injury is the most common sports injury in orthopaedics, which can adversely affect knee joint function and exercise of patients. Using arthroscopy to reconstruct the anterior cruciate ligament has become the first choice for treating anterior cruciate ligament rupture. However, different degrees of articular cartilage injury of the knee can be observed in patients after anterior cruciate ligament reconstruction. More importantly, the articular cartilage injury after anterior cruciate ligament reconstruction indicates that it will develop into osteoarthritis in the long term. It is of great significance to fully understand the factors that lead to the occurrence and development of cartilage injury. This article reviews the effects of surgical methods, meniscus status, different grafts, time from injury to surgical intervention, postoperative knee joint stability, postoperative rehabilitation, knee joint anatomical factors, and demographic characteristics of patients on articular cartilage degeneration after anterior cruciate ligament reconstruction. The present review provides insights into the anterior cruciate ligament reconstruction, which can be used to investigate new treatment strategies to delay and prevent the progress of osteoarthritis. At the same time, it provides a holistic understanding of the influence of multiple factors on cartilage lesions after anterior cruciate ligament reconstruction.

The burden of end-stage osteoarthritis in Australia: a population-based study on the incidence of total knee replacement attributable to overweight/obesity

OBJECTIVES

To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population.

METHODS

This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015 and 2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence.

RESULTS

The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 14,287 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category.

CONCLUSIONS

Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided.

Relationship Between the Choice of Clinical Treatment, Gait Functionality and Kinetics in Patients With Comparable Knee Osteoarthritis

Objective: The objective of this study was to investigate the relationship between the choice of clinical treatment, gait functionality, and kinetics in patients with comparable knee osteoarthritis.

Design: This was an observational case-control study.

Setting: The study was conducted in a university biomechanics laboratory.

Participants: Knee osteoarthritis patients were stratified into the following groups: clinical treatment (conservative/total knee replacement (TKR) planned), sex (male/female), age (60–67/68–75), and body mass index (BMI) (&lt;30/≥30). All patients had a Kellgren–Lawrence score of 2 or 3 (N = 87).

Main Outcome Measures: All patients underwent gait analysis, and two groups of dependent variables were extracted:

• Spatiotemporal gait variables: gait velocity, stride time, and double-support time, which are associated with patient functionality.

• Kinetic gait variables: vertical, anterior–posterior, and mediolateral ground reaction forces, vertical free moment, joint forces, and moments at the ankle, knee, and hip. Multifactorial and multivariate analyses of variance were performed.

Results: Functionality relates to treatment decisions, with patients in the conservative group walking 25% faster and spending 24% less time in the double-support phase. However, these differences vary with age and are reduced in older subjects. Patients who planned to undergo TKR did not present higher knee forces, and different joint moments between clinical treatments depended on the age and BMI of the subjects.

Conclusions: Knee osteoarthritis is a multifactorial disease, with age and BMI being confounding factors. The differences in gait between the two groups were mitigated by confounding factors and risk factors, such as being a woman, elderly, and obese, reducing the variability of the gait compression loads. These factors should always be considered in gait studies of patients with knee osteoarthritis to control for confounding effects.

Adiponectin in Osteoarthritis: Pathophysiology, Relationship with Obesity and Presumptive Diagnostic Biomarker Potential

Osteoarthritis (OA) is a multifactorial, irreversible age- and obesity-induced joint degenerative disease, with an increasing incidence in developed countries. With a pathophysiology and etiology that are currently under-investigated, the only available disease-modifying treatment relies solely on total joint arthroplasty, which entails major economic burdens. Recently, the research focus has shifted towards the evaluation of metabolically active mediators secreted by the adipose tissue, which could be potential targets for a better understanding of the mechanisms involved in OA onset and development. Of note, adiponectin has drawn a great deal of attention, since it is the most abundant type of circulating adipokine and has been highly associated with OA occurrence. Thus far, studies have been controversial in establishing whether adiponectin possesses a destructive or protective role in OA development. Therefore, we critically and systematically reviewed, herein, the roles of adiponectin in the pathophysiology of OA, the link between obesity, adiponectin expression and the progression of OA, as well as its potential role as a future biomarker for a more optimized and reliable diagnosis of this degenerative disorder.

Molecular Classification of Knee Osteoarthritis

Knee osteoarthritis (KOA) is the most common form of joint degeneration with increasing prevalence and incidence in recent decades. KOA is a molecular disorder characterized by the interplay of numerous molecules, a considerable number of which can be detected in body fluids, including synovial fluid, urine, and blood. However, the current diagnosis and treatment of KOA mainly rely on clinical and imaging manifestations, neglecting its molecular pathophysiology. The mismatch between participants' molecular characteristics and drug therapeutic mechanisms might explain the failure of some disease-modifying drugs in clinical trials. Hence, according to the temporal alteration of representative molecules, we propose a novel molecular classification of KOA divided into pre-KOA, early KOA, progressive KOA, and end-stage KOA. Then, progressive KOA is furtherly divided into four subtypes as cartilage degradation-driven, bone remodeling-driven, inflammation-driven, and pain-driven subtype, based on the major pathophysiology in patient clusters. Multiple clinical findings of representatively investigated molecules in recent years will be reviewed and categorized. This molecular classification allows for the prediction of high-risk KOA individuals, the diagnosis of early KOA patients, the assessment of therapeutic efficacy, and in particular, the selection of homogenous patients who may benefit most from the appropriate therapeutic agents.

Blood flow restriction training in patients with knee osteoarthritis: Systematic review of randomized controlled trials

INTRODUCTION

Knee osteoarthritis (KOA) is one of the most common musculoskeletal disorders in the elderly. The patient experiences reduction in muscle strength, pain, joint stiffness and consequently a reduction in quality of life. Whereas high intensity training (HI-TR) is the most effective in the general elderly population, in KOA patients, painless alternatives might be more suitable, since pain can be a deterrent for exercising. Research interest has increased in blood flow restriction training (BFR-TR) due to the observation that, in this specific population, BFR-TR results in equal muscular adaptions to HI-TR but with less join discomfort/pain.

OBJECTIVE

We aimed to: (1) determine the value of BFR-TR in patients with KOA and (2) examine which exercise guidelines applied to healthy elderly populations can be adopted for patients suffering from this knee pathology.

METHODOLOGY

We searched the literature from the database inception to 2019 through PubMed, Cochrane, and Medline (EBSCO). The inclusion criteria were determined using PICOS principles. We assessed methodology using the Risk of Bias 2 tool and the Pedro scale. Conclusions were extracted with the use of best evidence synthesis.

RESULTS

The literature search yielded 45 articles. After screening, three studies matched the inclusion criteria. The included studies were analyzed and discussed. All the included studies reported within group improvements for BFR-TR regarding pain and strength.

CONCLUSION

Although the evidence of BFR-TR efficacy on KOA remains scarce, the results favor its use for muscle strengthening and pain reduction in KOA. Further high-quality studies with larger samples are required.

Relaxation capacity of cartilage is a critical factor in rate- and integrity-dependent fracture

Articular cartilage heals poorly but experiences mechanically induced damage across a broad range of loading rates and matrix integrity. Because loading rates and matrix integrity affect cartilage mechanical responses due to poroviscoelastic relaxation mechanisms, their effects on cartilage failure are important for assessing and preventing failure. This paper investigated rate- and integrity-dependent crack nucleation in cartilage from pre- to post-relaxation timescales. Rate-dependent crack nucleation and relaxation responses were obtained as a function of matrix integrity through microindentation. Total work for crack nucleation increased with decreased matrix integrity, and with decreased loading rates. Critical energy release rate of intact cartilage was estimated as 2.39 ± 1.39 to 2.48 ± 1.26 kJ m-2 in a pre-relaxation timescale. These findings showed that crack nucleation is delayed when cartilage can accommodate localized loading through poroviscoelastic relaxation mechanisms before fracture at a given loading rate and integrity state.

Effectiveness of Stepped-Care Intervention in Overweight and Obese Patients With Medial Tibiofemoral Osteoarthritis: A Randomized Controlled Trial

OBJECTIVE

To test the effectiveness of a 32-week, stepped-care intervention on disease remission rates in overweight and obese patients with medial tibiofemoral osteoarthritis (OA) compared to controls.

METHODS

In this randomized controlled trial, eligible participants were ≥50 years of age with a body mass index of ≥28 kg/m² and radiographic evidence of medial tibiofemoral OA. Participants were randomized to stepped-care (n = 87) or control group (n = 84). The stepped-care group received a 2-step intervention. The first step consisted of an 18-week diet and exercise program. The second step consisted of 4 treatment subgroups: 1) diet and exercise maintenance; 2) cognitive-behavioral therapy; 3) unloader knee brace; and 4) muscle strengthening exercises. Allocation into subgroups was based on disease remission state and clinical characteristics. The primary end point was the disease remission rate (yes/no) at 32 weeks, which was reached when participants achieved the Patient Acceptable Symptom State cutoff value for pain and for the patient global assessment of disease activity and/or functional impairment.

RESULTS

Disease remission at 32 weeks was achieved by 18 of 68 (26%) in the control group and 32 of 82 (39%) in the stepped-care group (difference 12.6% [95% confidence interval -2.3, 27.4], P = 0.10). The stepped-care group showed an improvement in pain and function between baseline and 20 weeks. While functional improvement was maintained at 32 weeks, pain levels tended to get worse between weeks 20 and 32.

CONCLUSION

The proposed intervention did not promote a significant difference in the rate of disease remission in comparison to the control group for overweight or obese patients with medial tibiofemoral OA.

Risk Factors Related to the Presence of Meniscal Injury and Irreparable Meniscal Tear at Primary Anterior Cruciate Ligament Reconstruction

Background:

Few studies have attempted to identify risk factors associated with irreparable meniscal tears at anterior cruciate ligament reconstruction (ACLR) and to describe follow-up data, such as the failure rate, after meniscal repair.

Purpose:

To investigate the associations of age, sex, body mass index (BMI), time to surgery (TTS), and preinjury Tegner score with the presence of meniscal injuries and irreparable meniscal tears at primary ACLR.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A retrospective review was performed on 784 patients who underwent primary ACLR by a single surgeon between 2005 and 2017 (406 men and 378 women; mean age, 25.8 years; mean BMI, 23.1; median TTS, 3 months; median preinjury Tegner score, 7). All patients had a minimum follow-up of 12 months (mean postoperative follow-up, 33.0 months). Multivariate logistic regression analysis was conducted to determine the association of patient variables with the presence of meniscal injuries and irreparable meniscal tears during primary ACLR.

Results:

The risk factor for medial meniscal injuries was TTS ≥3 months (odds ratio [OR], 4.213; 95% CI, 3.104-5.719; P < .001). The presence of irreparable medial meniscal tears increased with older age (OR, 1.053; 95% CI, 1.024-1.084; P < .001), higher BMI (OR, 1.077; 95% CI, 1.003-1.156; P = .042), and TTS ≥3 months (OR, 1.794; 95% CI, 1.046-3.078; P = .034). On multivariate analysis, none of the variables were significantly associated with lateral meniscal injuries and irreparable meniscal tears. The failure rate, defined as patients who needed additional medial meniscal surgery after medial meniscal repair, was 4.6%.

Conclusion:

Time from ACL injury to reconstruction of ≥3 months was strongly associated with medial meniscal injuries and irreparable medial meniscal tears at primary ACLR. Older age and increased BMI were also risk factors for the presence of irreparable medial meniscal tears at ACLR.

Risk factors for progression to total knee arthroplasty within two years of presentation for knee osteoarthritis

INTRODUCTION

Knee osteoarthritis (OA) is a leading cause of disability and functional limitations in aging adults. Total knee arthroplasty (TKA) is the gold standard treatment of this condition. The purpose of this study is to evaluate which patient characteristics are associated with proceeding to TKA.

METHODS

Retrospective review of patients with knee osteoarthritis at a single institution was conducted. Demographic, radiographic and clinical patient characteristics were analyzed. The primary outcome measure was whether patients underwent TKA over the study time-period. Univariate comparisons between patients not undergoing surgery and those undergoing TKA were performed. Multivariate logistic regression was performed to evaluate risk factors for undergoing TKA.

RESULTS

Two hundred seven patients were included in the study. One hundred eighty seven patients (90.3%) did not undergo surgery, while 20 (9.7%) underwent TKA. No statistically significant differences in demographics were observed between patients who underwent TKA and those who did not. On multivariate analysis, patients with Kellgren Lawrence grade 4 OA (OR: 20.793, p = 0.009) and varus alignment (OR: 13.044, p = 0.040) were at significantly increased risk of undergoing TKA. Using only these two variables, the area under the curve for predicting which patients would undergo TKA was 0.846, indicating excellent discrimination.

CONCLUSION

In patients diagnosed with knee OA, Kellgren Lawrence grade 4 classification and varus knee alignment are significant risk factors for undergoing TKA, and are associated with a decreased time from initial presentation to surgery. These findings may be used to counsel patients, aid triage decisions, and inform the development of future predictive models.

Body Mass Index and Musculoskeletal Pain: A Cross-Sectional Study

Introduction

With obesity reaching pandemic proportions, its detrimental influence on many health-related conditions has recently become a focus of research. Musculoskeletal (MSK) pain is one of several disorders associated with obesity.

Materials and methods

This study was designed to identify MSK pain in individuals with severe obesity, recruited from a specialized obesity clinic, and to evaluate the correlation between the MSK symptoms and some individual criteria.

Results

In 466 patients (342 females and 124 males), with a mean BMI of 42,77 ± 5.64 kg/m², 90,3% reported MSK pain. Severe pain was reported by 57,8% of female vs 26,6% of male patients. Female patients showed higher mean pain level when compared with males. Body sites with a higher prevalence of pain were: knee (63.5%), lumbar region (46.8%), hip (29%) and ankle (23%), with a predominance of severe pain. BMI have shown a positive correlation to numeric rating scale score in female participants in three body regions: shoulder (P = 0.010), knee (P = 0.042) and ankle (P = 0.024). Body sites with higher pain prevalence were especially in areas of increased mechanical load.

Conclusions

Understanding the relationship between obesity and pain may provide insights into preventive measures and therapeutic strategies for MSK pain. Persistent MSK pain is a significant problem in obese patients that can have a negative relationship with quality of life and function. This fact highlights the importance that patients with obesity may have access to interdisciplinary care, for the prevention and rehabilitation of MSK disorders. To further understand this association, more robust studies are needed.

Interval Between Staged Bilateral Total Knee Arthroplasties Does Not Affect Early Medical or Surgical Complications

BACKGROUND

The purpose of this study is to evaluate early postoperative surgical and medical complications in patients undergoing staged bilateral total knee arthroplasty (TKA) and determine if the interval to the second stage influences the risk of complications.

METHODS

A retrospective review was performed from 2016 through 2018 of all staged bilateral primary TKA procedures, yielding a cohort of 1005 patients (2010 TKAs). Four groups were created based on the timing of the second stage: 3 to 6 weeks, 7 to 12 weeks, 13 to 24 weeks, and >24 weeks. Clinical data compared between groups included demographics, knee range of motion, University of California, Los Angeles (UCLA) activity score, Knee Society pain score, Knee Society clinical score, and Knee Society functional score. Postoperative complications within 90 days were evaluated, with complications after the second knee being the primary outcome.

RESULTS

The mean follow-up after second stage was 10.7 months (range, 3 to 37 months). No significant differences were found between groups in the range of motion, Knee Society pain, Knee Society clinical score, Knee Society functional score, or University of California Los Angeles activity score in either the first or second knee. After the first knee surgery, medical complications were highest in the >24-week group. After the second knee, there were no significant difference in manipulation (P = .9), wound complications (P = .7), venous thromboembolism (P = .8), or other medical complications (P = 1) based on the interval duration.

CONCLUSION

The interval between staged TKA did not affect early medical or surgical complications after the second stage. Early clinical and function results were not different based on timing of the second surgery.

Adenosine A2A receptor signaling promotes FoxO associated autophagy in chondrocytes

Autophagy, a homeostatic pathway upregulated during cellular stress, is decreased in osteoarthritic chondrocytes and this reduction in autophagy is thought to contribute to the development and progression of osteoarthritis (OA). The adenosine A2A receptor (A2AR) is a potent anti-inflammatory receptor and deficiency of this receptor leads to the development of OA in mice. Moreover, treatment using liposomally conjugated adenosine or a specific A2AR agonist improved joint scores significantly in both rats with post-traumatic OA (PTOA) and mice subjected to a high fat diet obesity induced OA. Importantly, A2AR ligation is beneficial for mitochondrial health and metabolism in vitro in primary and the TC28a2 human cell line. An additional set of metabolic, stress-responsive, and homeostatic mediators include the Forkhead box O transcription factors (FoxOs). Data has shown that mouse FoxO knockouts develop early OA with reduced cartilage autophagy, indicating that FoxO-induced homeostasis is important for articular cartilage. Given the apparent similarities between A2AR and FoxO signaling, we tested the hypothesis that A2AR stimulation improves cartilage function through activation of the FoxO proteins leading to increased autophagy in chondrocytes. We analyzed the signaling pathway in the human TC28a2 cell line and corroborated these findings in vivo in a metabolically relevant obesity-induced OA mouse model. We found that A2AR stimulation increases activation and nuclear localization of FoxO1 and FoxO3, promotes an increase in autophagic flux, improves metabolic function in chondrocytes, and reduces markers of apoptosis in vitro and reduced apoptosis by TUNEL assay in vivo. A2AR ligation additionally enhances in vivo activation of FoxO1 and FoxO3 with evidence of enhanced autophagic flux upon injection of the liposome-associated A2AR agonist in a mouse obesity-induced OA model. These findings offer further evidence that A2AR may be an excellent target for promoting chondrocyte and cartilage homeostasis.

Efficacy of some Herbal Medicines in Osteoarthritis with a Focus on Topical Agents: A Systematic Review

Osteoarthritis (OA) is a leading cause of musculoskeletal disorders that mainly affects the elderly population. Some herbal medicines have the potential to alleviate the pain associated with OA and improve physical activity mostly through anti-inflammatory and anti-oxidative properties. The aim of this study was to investigate the effects of herbal medicines, especially topical types, on osteoarthritis. In this systematic review, the keywords "osteoarthritis", "herbal compounds", "herbal medicine", "topical drug", "hydrogels", "cream" and "treatment" were used to search publications published from 2010 to 2019 and indexed in databases including PubMed, SCOPUS, Web of Science and Google Scholar. After screening of titles and abstracts and detection of duplicate publications, 38 eligible articles were included in the main review. We also included herbal formulations in vivo. Bioactive fractions of herbal medicines mostly worked on OA through suppression of interleukin-1β (IL-1β), inducing nuclear factor-κB (NF-κB) activation by inhibition of inhibitor of NF-κB (IκBα) phosphorylation, IκBα degradation, p65 phosphorylation, and p65 nuclear translocation, downregulation of NF-κB targets including COX-2 and MMPs, upregulation of collagen type II, cartilage-specific proteoglycans (CSPGs), β1-integrin, and expression of cartilage-specific transcription factor SOX-9 protein. Noticeably, herbal medicines do not produce desirable effects, thereby using their combinations with other therapeutic agents seem to exert substantial clinical outcomes. Herbal gels have demonstrated robustly significant healing effects on knee pain, stiffness and mobility. It is worth considering that because OA is a chronic disease, longer duration of the studies/trials would even lead to obtaining more reliable judgments regarding topical treatment tolerability, safety and efficacy and clarify local or systemic adverse effects. Stability and standardization of a defined amount or concentrations of herbal gels would give promising effects on OA treatment and pain relief.

A randomized control trial on retro-walking improves symptoms, pain, and function in primary knee osteoarthritis

BACKGROUND

Primary knee osteoarthritis is the leading cause of chronic disability and pain among adults worldwide. Retro-walking has been shown to reduce patellofemoral pain, increases functional capability while strengthening the lower limbs and improving proprioception and balance. We aim to examine the effects of retro-walking on symptoms, pain, and perceived ability to perform daily activities in comparison to forward-walking in subjects with primary knee osteoarthritis.

METHODS

This was a single-blinded, randomized control trial involving 34 subjects between the age of 45-70 years (58.41±5.93) comparing retro-walking (RW) to forward-walking (FW). Subjects were randomly allocated to receive either RW with structured resistance training (SRT) or FW with SRT; 3 times a week for 12 weeks. The symptoms, pain, and function of daily living sub scores of the Knee Injury and Osteoarthritis Outcome Score (KOOS) along with Timed up and go (TUG) and Chair stand test (CST) were assessed at baseline and after 12 weeks. The outcomes were analyzed with two-way repeated measure analysis of variance.

RESULTS

Significant improvements for all outcomes were observed intra-group (P value <0.05) after 12 weeks. The KOOS sub scores, TUG and CST times was not statistically significant between study groups (P value >0.05). However, the partial eta squared scores for all outcomes were better in the RW group compared to FW except for CST.

CONCLUSIONS

It can be concluded that RW is a feasible and non-inferior option to FW in the rehabilitation of subjects with bilateral knee OA.

Obesity with radiological changes or depression was associated with worse knee outcome in general population: a cluster analysis in the Nagahama study

Background

In knee osteoarthritis (OA), pain is the most frequent and dominant symptom. However, which factors other than radiological changes contribute to the symptoms is unresolved. The aims of this study were to identify factors affecting knee pain from various variables with radiological changes taken into count and exploratively examine what subgroups or phenotype could be identified by cluster analysis using the identified knee pain factors.

Methods

Patients 60 years or older who underwent radiographic evaluation were included in this cross-sectional study, and those subjects who completed a questionnaire about knee symptoms without missing data were eligible for analysis. Multiple regression analysis was used to examine the associations between selected variables and The Japanese Knee Osteoarthritis Measure (JKOM) pain score. We grouped the subjects by cluster analysis using identified variables.

Results

Two thousand five hundred forty-two subjects were included in the full set of analyses. Age, body mass index (BMI), radiological grade, bone mineral density (BMD), and high-sensitivity C-reactive protein (hs-CRP) showed a statistically significant correlation with radiological showing the strongest value. For dichotomous variable, presence of depression showed a statistically significant result. We used BMI, radiological grade, BMD, hs-CRP, and presence of depression as a variable for cluster analysis and identified six subgroups: (1) minimal joint disease subgroup, (2) male and high BMD subgroup, (3) high CRP subgroup, (4) severe radiological OA subgroup, (5) depressive subgroup, and (6) moderate radiological OA with high BMI subgroup, showing the worst knee outcome.

Conclusion

This study identified the factors affecting knee pain other than radiological changes and identified six subgroups of knee outcome in the general population. The results showed that obesity with radiological changes or depression was associated with worse knee outcome.

Do Patients With Osteoarthritis get Weight Loss Counseling?

INTRODUCTION

Osteoarthritis (OA) is a degenerative disease of joints which if untreated can lead to a permanent disability of joints. Obesity plays an important role in the morbidity of OA. Since there is no curative treatment for OA, several researches focusing on nonpharmacological intervention for OA have come forth. Triad of education, exercise, and weight loss has been gaining popularity as a first-line nonpharmacological treatment for OA. This article measures the number of OA patients, irrespective of age and gender, who have received weight-loss counseling from their physicians and it also studies patients' willingness to lose weight after being counseled.

METHODOLOGY

A cross-sectional study was conducted from 10th June 2020 to 10th July 2020. Diagnosed cases of OA were included and their consent was taken. A self-administered questionnaire was used which included questions asking if they have ever received weight-loss counseling and if they will try to lose weight on being advised by their physician. Data were collected from the participants using google forms and analyzed using SPSS-22.

RESULTS

Out of 199 OA patients included in our study, only 28 (14%) participants received weight loss and exercise counseling from their physicians. A positive response was observed in 175 (87.9%) participants out of 199 who reported that they would exercise and practice a healthy lifestyle to lose weight if they were advised properly.

CONCLUSION

Results of our study showed that the total number of OA patients receiving advice from their treating physician regarding weight loss is less. However, the majority of the patients were willing to exercise and control their weight if advised properly by their physician.

Automatic Grading of Individual Knee Osteoarthritis Features in Plain Radiographs Using Deep Convolutional Neural Networks

Knee osteoarthritis (OA) is the most common musculoskeletal disease in the world. In primary healthcare, knee OA is diagnosed using clinical examination and radiographic assessment. Osteoarthritis Research Society International (OARSI) atlas of OA radiographic features allows performing independent assessment of knee osteophytes, joint space narrowing and other knee features. This provides a fine-grained OA severity assessment of the knee, compared to the gold standard and most commonly used Kellgren–Lawrence (KL) composite score. In this study, we developed an automatic method to predict KL and OARSI grades from knee radiographs. Our method is based on Deep Learning and leverages an ensemble of residual networks with 50 layers. We used transfer learning from ImageNet with a fine-tuning on the Osteoarthritis Initiative (OAI) dataset. An independent testing of our model was performed on the Multicenter Osteoarthritis Study (MOST) dataset. Our method yielded Cohen’s kappa coefficients of 0.82 for KL-grade and 0.79, 0.84, 0.94, 0.83, 0.84 and 0.90 for femoral osteophytes, tibial osteophytes and joint space narrowing for lateral and medial compartments, respectively. Furthermore, our method yielded area under the ROC curve of 0.98 and average precision of 0.98 for detecting the presence of radiographic OA, which is better than the current state-of-the-art.

Association between low back pain and body mass index in adult twins: an analysis of monozygotic and dizygotic twins of the Washington State Twin Registry

BACKGROUND CONTEXT

Low back pain (LBP) is a common and significant cause of disability worldwide, however; questions about cause still remain.

PURPOSE

To investigate the association between LBP, body mass index (BMI), and moderate to vigorous physical activity (MVPA) in a twin sample.

STUDY DESIGN

Cross sectional study of monozygotic (MZ) and dizygotic (DZ) twins from the Washington State Twin Registry.

PATIENT SAMPLE

Monozygotic and dizygotic twins from the Washington State Twin Registry.

OUTCOME MEASURES

Self-report measures: Low back pain, body mass index, duration and intensity of exercise.

METHODS

The sample included 5,183 same-sex pairs (69% MZ). The outcome was self-reported diagnosis of LBP from a health care provider. A phenotypic model tested the association between BMI and LBP without including genetic or shared environmental confounds. We then re-estimated the association using a quasi-causal model which controls for those confounds. Finally, we used a mediation model to investigate if the association between LBP and MVPA was mediated by BMI.

RESULTS

In the phenotypic regression of LBP on BMI, there was a ~4-fold increase in the odds of having LBP with every one-unit increase in BMI (odds ratio [OR] =3.83; 95% confidence interval =3.28, 4.46). However, quasi-causal regression of LBP on BMI was reduced to zero (OR =0.95; 95% confidence interval =0.60, 1.49). A significant genetic background to BMI and LBP was present (b_A =1.66; p<.001), even after controlling for confounders. In another analysis there was a significant direct effect between MVPA and LBP (b_p=-0.092, standard error [SE] =0.017, p<.001). In mediation analysis, the effect of MVPA on LBP was partially mediated through MVPA effects on BMI ( [Formula: see text] =-0.043, SE=0.003, p<.001) and BMI effects on LBP ( [Formula: see text] =1.281, SE=0.079, OR=3.6, p<.001), however shared environmental factors confounded this relationship.

CONCLUSIONS

BMI was not associated with LBP, despite sharing a phenotypic association, but they may share a genetic influence. The effect of MVPA on LBP is, in part, mediated by BMI but shared environment confounds this relationship.

LEVEL OF EVIDENCE

Level 3.

The Association of an Increasing Waist Circumference and Risk of Incident Low Physical Function in Adults with Knee Osteoarthritis

OBJECTIVE

To investigate an 8-year change in waist circumference (WC) with the risk of incident low physical function over 1 year in adults with, or at risk of, knee osteoarthritis (OA).

METHODS

Data from the Osteoarthritis Initiative were used. Change in WC was measured from study enrollment (0 month) to the 96-month visit and classified as Increase (≥ 5cm gain) or Maintain (< 5cm gain). We identified World Health Organization (WHO) risk category based on WC at study enrollment as Large WC (males ≥ 102 cm, females ≥ 88 cm) or Small WC (males < 102 cm, females < 88 cm). The outcome was incident low physical function (≥ 28 Western Ontario and McMaster Universities Osteoarthritis Index physical function subscale) at the 108-month visit. To investigate the association of the 8-year change in WC with the risk of low physical function, we calculated risk ratios (95% CI) and adjusted for potential confounders. We repeated the analyses stratified by the WHO disease risk category.

RESULTS

The Increase WC group had 1.43 (95% CI 1.04-1.96) times the risk of incident low physical function compared to adults in the Maintain WC group. Adults with a Large WC at baseline who increased WC had 1.55 (95% CI 1.00-2.37) times the risk of incident low physical function compared to those who maintained WC. Adults with a Small WC at baseline who increased WC had 1.97 (95% CI 0.84-4.63) times the risk compared to those who maintained WC.

CONCLUSION

Increasing WC increases the risk of incident low physical function in the following year. Maintaining WC may mitigate developing low physical function.

Purinergic System Signaling in Metainflammation-Associated Osteoarthritis

Inflammation triggered by metabolic imbalance, also called metainflammation, is low-grade inflammation caused by the components involved in metabolic syndrome (MetS), including central obesity and impaired glucose tolerance. This phenomenon is mainly due to excess nutrients and energy, and it contributes to the pathogenesis of osteoarthritis (OA). OA is characterized by the progressive degeneration of articular cartilage, which suffers erosion and progressively becomes thinner. Purinergic signaling is involved in several physiological and pathological processes, such as cell proliferation in development and tissue regeneration, neurotransmission and inflammation. Adenosine and ATP receptors, and other members of the signaling pathway, such as AMP-activated protein kinase (AMPK), are involved in obesity, type 2 diabetes (T2D) and OA progression. In this review, we focus on purinergic regulation in osteoarthritic cartilage and how different components of MetS, such as obesity and T2D, modulate the purinergic system in OA. In that regard, we describe the critical role in this disease of receptors, such as adenosine A2A receptor (A2AR) and ATP P2X7 receptor. Finally, we also assess how nucleotides regulate the inflammasome in OA.

Fish oil supplementation reduces osteoarthritis-specific pain in older adults with overweight/obesity

Objectives

OA is a leading cause of chronic pain and disability. Next to inflammation, vascular pathology has been hypothesized to play a role in its aetiology and progression. Owing to side effects and the low efficacy of pharmacological treatments, dietary supplements are popular as alternative treatments, but evidence of efficacy is limited. We tested whether fish oil and curcumin supplementation can reduce chronic pain and OA burden in older adults.

Methods

A 16-week randomized, double-blind, placebo-controlled, 2 × 2 factorial design supplementation trial with fish oil (2000 mg/day docosahexaenoic acid + 400 mg/day eicosapentaenoic acid), curcumin (160 mg/day) or a combination of both was undertaken in sedentary overweight/obese older adults. Secondary outcomes included treatment-induced changes in self-reported chronic pain and OA burden and whether changes were related to changes in small artery elasticity (surrogate marker for microvascular function), CRP (inflammatory marker) and well-being.

Results

The majority of participants (131 of 152) reported chronic pain, which was predominantly OA specific. Fish oil significantly reduced OA-specific pain (P = 0.002, Cohen’s d = 0.56) and burden (P = 0.015, Cohen’s d = 0.45) compared with no fish oil treatment; reductions were correlated with improvements in microvascular function and well-being. Curcumin, alone or in combination with fish oil, did not reduce pain measures.

Conclusion

Our findings indicate potential for fish oil to alleviate OA pain and burden in overweight/obese older adults. Further investigations should be undertaken in patients with clinically diagnosed OA to evaluate fish oil alone and as an adjunct to conventional pharmacotherapy and to investigate underlying mechanisms.

Trial registration

Australian and New Zealand Clinical Trials Register, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=370788, ACTRN12616000732482p.

Predicting Incident Radiographic Knee Osteoarthritis in Middle-Aged Women Within Four Years: The Importance of Knee-Level Prognostic Factors

OBJECTIVE

To develop and internally validate risk models and a clinical risk score tool to predict incident radiographic knee osteoarthritis (RKOA) in middle-aged women.

METHODS

We analyzed 649 women in the Chingford 1,000 Women study. The outcome was incident RKOA, defined as Kellgren/Lawrence grade 0-1 at baseline and ≥2 at year 5. We estimated predictors' effects on the outcome using logistic regression models. Two models were generated. The clinical model considered patient characteristics, medication, biomarkers, and knee symptoms. The radiographic model considered the same factors, plus radiographic factors (e.g., angle between the acetabular roof and the ilium's vertical cortex [hip α-angle]). The models were internally validated. Model performance was assessed using calibration and discrimination (area under the receiver characteristic curve [AUC]).

RESULTS

The clinical model contained age, quadriceps circumference, and a cartilage degradation marker (C-terminal telopeptide of type II collagen) as predictors (AUC = 0.692). The radiographic model contained older age, greater quadriceps circumference, knee pain, knee baseline Kellgren/Lawrence grade 1 (versus 0), greater hip α-angle, greater spinal bone mineral density, and contralateral RKOA at baseline as predictors (AUC = 0.797). Calibration tests showed good agreement between the observed and predicted incident RKOA. A clinical risk score tool was developed from the clinical model.

CONCLUSION

Two models predicting incident RKOA within 4 years were developed, including radiographic variables that improved model performance. First-time predictor hip α-angle and contralateral RKOA suggest OA origins beyond the knee. The clinical tool has the potential to help physicians identify patients at risk of RKOA in routine practice, but the tool should be externally validated.

Horizontal fissuring at the osteochondral interface: a novel and unique pathological feature in patients with obesity-related osteoarthritis

Objectives

Obesity is a well-recognised risk factor for osteoarthritis (OA). Our aim is to characterise body mass index (BMI)-associated pathological changes in the osteochondral unit and determine if obesity is the major causal antecedent of early joint replacement in patients with OA.

Methods

We analysed the correlation between BMI and the age at which patients undergo total knee replacement (TKR) in 41 023 patients from the Australian Orthopaedic Association National Joint Replacement Registry. We then investigated the effect of BMI on pathological changes of the tibia plateau of knee joint in a representative subset of the registry.

Results

57.58% of patients in Australia who had TKR were obese. Patients with overweight, obese class I & II or obese class III received a TKR 1.89, 4.48 and 8.08 years earlier than patients with normal weight, respectively. Microscopic examination revealed that horizontal fissuring at the osteochondral interface was the major pathological feature of obesity-related OA. The frequency of horizontal fissure was strongly associated with increased BMI in the predominant compartment. An increase in one unit of BMI (1 kg/m²) increased the odds of horizontal fissures by 14.7%. 84.4% of the horizontal fissures were attributable to obesity. Reduced cartilage degradation and alteration of subchondral bone microstructure were also associated with increased BMI.

Conclusions

The key pathological feature in OA patients with obesity is horizontal fissuring at the osteochondral unit interface. Obesity is strongly associated with a younger age of first TKR, which may be a result of horizontal fissures.

Obesity is Associated with an Increased Prevalence of Glenohumeral Osteoarthritis and Arthroplasty: A Cohort Study

The relationship between obesity and glenohumeral osteoarthritis is relatively understudied. The purpose of this study was to better define this relationship by age- and gender-matching 596,874 patients across six body mass index (BMI) cohorts and determining the prevalence of glenohumeral osteoarthritis and the standardized rate of glenohumeral arthroplasty in each cohort. Individuals with a BMI over 24 were found to be at increased odds for developing glenohumeral osteoarthritis, compared to the normal BMI cohort, and individuals with a BMI over 30 were additionally found to be at increased odds for undergoing glenohumeral arthroplasty.

Cost-Effectiveness of Diet and Exercise for Overweight and Obese Patients With Knee Osteoarthritis

OBJECTIVE

The Intensive Diet and Exercise for Arthritis (IDEA) trial showed that an intensive diet and exercise (D+E) program led to a mean 10.6-kg weight reduction and 51% pain reduction in patients with knee osteoarthritis (OA). The aim of the current study was to investigate the cost-effectiveness of adding this D+E program to treatment in overweight and obese (body mass index >27 kg/m² ) patients with knee OA.

METHODS

We used the Osteoarthritis Policy Model to estimate quality-adjusted life-years (QALYs) and lifetime costs for overweight and obese patients with knee OA, with and without the D+E program. We evaluated cost-effectiveness with the incremental cost-effectiveness ratio (ICER), a ratio of the differences in lifetime cost and QALYs between treatment strategies. We considered 3 cost-effectiveness thresholds: $50,000/QALY, $100,000/QALY, and $200,000/QALY. Analyses were conducted from health care sector and societal perspectives and used a lifetime horizon. Costs and QALYs were discounted at 3% per year. D+E characteristics were derived from the IDEA trial. Deterministic and probabilistic sensitivity analyses (PSAs) were used to evaluate parameter uncertainty and the effect of extending the duration of the D+E program.

RESULTS

In the base case, D+E led to 0.054 QALYs gained per person and cost $1,845 from the health care sector perspective and $1,624 from the societal perspective. This resulted in ICERs of $34,100/QALY and $30,000/QALY. In the health care sector perspective PSA, D+E had 58% and 100% likelihoods of being cost-effective with thresholds of $50,000/QALY and $100,000/QALY, respectively.

CONCLUSION

Adding D+E to usual care for overweight and obese patients with knee OA is cost-effective and should be implemented in clinical practice.

Phytohormones: Multifunctional nutraceuticals against metabolic syndrome and comorbid diseases

Metabolic syndrome is characterized by the co-occurrence of diverse symptoms initiating the development of type 2 diabetes, cardiovascular diseases, and a variety of comorbid diseases. The complex constellation of numerous comorbidities makes it difficult to develop common therapeutic approaches that ameliorate these pathological features simultaneously. The plant hormones abscisic acid, salicylic acid, auxin, and cytokinins, have shown promising anti-inflammatory and pro-metabolic effects that could mitigate several disorders relevant to metabolic syndrome. Intriguingly, besides plants, human cells and gut microbes also endogenously produce these molecules, indicating a role in the complex interplay between inflammatory responses associated with metabolic syndrome, the gut microbiome, and nutrition. Here, we introduce how bioactive phytohormones can be generated endogenously and through the gut microbiome. These molecules subsequently influence immune responses and metabolism. We also elaborate on how phytohormones can beneficially modulate metabolic syndrome comorbidities, and propose them as nutraceuticals.

Understanding the role of diabetes in the osteoarthritis disease and treatment process: a study protocol for the Swedish Osteoarthritis and Diabetes (SOAD) cohort

INTRODUCTION

Osteoarthritis (OA) is the most common form of arthritis and a leading cause of disability worldwide. Metabolic comorbidities such as type II diabetes occur with a higher rate in people with OA than in the general population. Several factors including obesity, hyperglycaemia toxicity and physical inactivity have been suggested as potential links between diabetes and OA, and have been shown to negatively impact patients' health and quality of life. However, little is known on the role of diabetes in determining the outcome of non-surgical and surgical management of OA, and at the same time, how different OA interventions may affect diabetes control. Thus, the overall aim of this project is to explore (1) the impact of diabetes on the outcome of non-surgical and surgical OA treatments and (2) the impact of non-surgical and surgical OA treatments on diabetes control.

METHODS AND ANALYSIS

The study cohort is based on prospectively ascertained register data on a national level in Sweden. Data from OA patients who received a first-line non-surgical intervention and are registered in the National Quality Register for Better Management of Patients with Osteoarthritis will be merged with data from the Swedish Knee and Hip Arthroplasty Registers and the National Diabetes Register. Additional variables regarding patients' use of prescribed drugs, comorbidities, socioeconomic status and cause of death will be obtained through other national health and population data registers. The linkage will be performed on an individual level using unique personal identity numbers.

ETHICS AND DISSEMINATION

This study received ethical approval (2019-02570) from the Swedish Ethical Review Authority. Results from this cohort will be submitted to peer-reviewed scientific journals and reported at the leading national and international meetings in the field.

Physical inactivity and knee osteoarthritis in guinea pigs

OBJECTIVE

To investigate whether and how a sedentary lifestyle contributes to knee osteoarthritis (OA) incidence and severity.

DESIGN

An experiment was conducted using Hartley guinea pigs, an established idiopathic knee OA model. To simulate a sedentary lifestyle, growing animals (n = 18) were housed for 22 weeks in small cages that restricted their mobility, while another group of animals (n = 17) received daily treadmill exercise to simulate moderate physical activity. After the experiment, histological assessments, biochemical assays, and mechanical testing were conducted to compare tibial articular cartilage structure, strength, and degree of OA degeneration between sedentary and physically active animals. Groups were also compared based on body weight and composition, as well as gut microbial community composition assessed using fecal 16S rRNA gene sequencing.

RESULTS

Prevalence of knee OA was similar between sedentary and physically active animals, but severity of the disease (cartilage lesion depth) was substantially greater in the sedentary group (P = 0.02). In addition, during the experiment, sedentary animals developed cartilage with lower aggrecan quantity (P = 0.03) and accumulated more body weight (P = 0.005) and visceral adiposity (P = 0.007). Groups did not differ greatly, however, in terms of cartilage thickness, collagen quantity, or stiffness, nor in terms of muscle weight, subcutaneous adiposity, or gut microbial community composition.

CONCLUSIONS

Our findings indicate that a sedentary lifestyle promotes the development of knee OA, particularly by enhancing disease severity rather than risk of onset, and this potentially occurs through multiple pathways including by engendering growth of functionally deficient joint tissues and the accumulation of excess body weight and adiposity.

Type 2 diabetes mellitus and osteoarthritis

OBJECTIVES

Type 2 diabetes mellitus (T2DM) and osteoarthritis (OA) are common diseases that frequently co-exist, along with overweight/obesity. While the mechanical impact of excess body weight on joints may explain lower limb OA, we sought to explore whether T2DM is linked to OA outside of excess weight and whether T2DM may play a role in OA pathophysiology. The consequence of T2DM on OA outcomes is a question of research interest.

METHODS

We conducted a critical review of the literature to explore the association between T2DM and OA, whether any association is site-specific for OA, and whether the presence of T2DM impacts on OA outcomes. We also reviewed the literature to assess the safety of anti-OA treatments in patients with T2DM.

RESULTS

T2DM has a pathogenic effect on OA through 2 major pathways involving oxidative stress and low-grade chronic inflammation resulting from chronic hyperglycemia and insulin resistance. T2DM is a risk factor for OA progression and has a negative impact on arthroplasty outcomes. Evidence is mounting for safety concerns with some of the most frequently prescribed anti-OA medications, including paracetamol, non-steroidal anti-inflammatory drugs, and corticosteroid injections, while other anti-OA medications may be safely prescribed in OA patients with T2DM, such as glucosamine and intra-articular hyaluronic acid.

CONCLUSIONS

Future research is needed to better understand whether diabetes control and prevention can modulate OA occurrence and progression. The selection of therapy to treat OA symptoms in patients with T2DM may require careful consideration of the evidence based to avoid untoward safety issues.