Incidence of total knee and hip replacement for osteoarthritis in relation to the metabolic syndrome and its components: a prospective cohort study

Osteoarthritis and the Mediterranean Diet: A Systematic Review

Osteoarthritis (OA) affects 240 million people globally. Few studies have examined the links between osteoarthritis and the Mediterranean diet (MD). The aim of this paper was to systematically review and analyze the epidemiological evidence in humans on the MD and its association with OA. A systematic search of EMBASE identified three studies that explored the association between MD and OA. Two of them were cross-sectional and the third one was a 16-week randomized clinical trial. Prisma declaration was followed to carry out this review. These studies described a positive association between a higher adherence to a MD and the quality of life of participants suffering OA. The prevalence of OA was lower in participants with a higher adherence to a Mediterranean diet. Biomarkers of inflammation and cartilage degradation related to OA were also analyzed and significant differences were detected only for IL1-α, which decreased in the MD group. Exploring the relationship between MD and OA is complex, moreover, the limited evidence and methodological differences in such studies makes it difficult to compare results. In conclusion, the three studies included in this systematic review demonstrated some relation between osteoarthritis and a Mediterranean diet. However, prospective and longer interventions are required to evaluate the long-term efficacy of the Mediterranean diet to improve symptomatology and preventing osteoarthritis.

Fatty acids and osteoarthritis: different types, different effects

While the association between obesity and osteoarthritis used to be solely regarded as a result of increased mechanical loading, systemic factors also likely play a role in the pathophysiology of osteoarthritis. Nutrient excess leading to obesity may result in lipotoxicity, which might be involved in the development of osteoarthritis. The different fatty acid types have distinct effects on inflammation. This review focusses on the currently available studies, summarizing the effects of the different fatty acid types on osteoarthritis and involved joint tissues. In animal studies omega-3 polyunsaturated fatty acids reduced the expression of inflammatory markers, cartilage degradation and oxidative stress in chondrocytes. In contrast, these markers were increased upon omega-6 polyunsaturated fatty acid and saturated fatty acid stimulation. Additionally, a decrease in pain and dysfunction was observed upon omega-3 supplementation in cats and dogs. In line, most human in vitro studies show pro-apoptotic and pro-inflammatory actions of saturated fatty acids. While all polyunsaturated fatty acids reduced markers of oxidative stress, omega-3 polyunsaturated fatty acids additionally decreased prostaglandin production. Human intervention studies with omega-3 polyunsaturated fatty acid supplementation may indicate a beneficial effect on pain and function and might be associated with less structural damage. In contrast, an adverse effect of saturated fatty acids on osteoarthritis has been observed. Monounsaturated fatty acids have been infrequently studied and findings are inconclusive. Existing studies indicate a promising effect of especially omega-3 polyunsaturated fatty acids on osteoarthritis signs and symptoms. However, more human intervention studies are warranted to draw robust conclusions.

What is the evidence for a role for diet and nutrition in osteoarthritis?

As current treatment options in OA are very limited, OA patients would benefit greatly from some ability to self-manage their condition. Since diet may potentially affect OA, we reviewed the literature on the relationship between nutrition and OA risk or progression, aiming to provide guidance for clinicians. For overweight/obese patients, weight reduction, ideally incorporating exercise, is paramount. The association between metabolic syndrome, type-2 diabetes and OA risk or progression may partly explain the apparent benefit of dietary-lipid modification resulting from increased consumption of long-chain omega-3 fatty-acids from oily fish/fish oil supplements. A strong association between OA and raised serum cholesterol together with clinical effects in statin users suggests a potential benefit of reduction of cholesterol by dietary means. Patients should ensure that they meet the recommended intakes for micronutrients such as vitamin K, which has a role in bone/cartilage mineralization. Evidence for a role of vitamin D supplementation in OA is unconvincing.

High-fat/high-sucrose diet-induced obesity results in joint-specific development of osteoarthritis-like degeneration in a rat model

Objectives

Metabolic syndrome and low-grade systemic inflammation are associated with knee osteoarthritis (OA), but the relationships between these factors and OA in other synovial joints are unclear. The aim of this study was to determine if a high-fat/high-sucrose (HFS) diet results in OA-like joint damage in the shoulders, knees, and hips of rats after induction of obesity, and to identify potential joint-specific risks for OA-like changes.

Methods

A total of 16 male Sprague-Dawley rats were allocated to either the diet-induced obesity group (DIO, 40% fat, 45% sucrose, n = 9) or a chow control diet (n = 7) for 12 weeks. At sacrifice, histological assessments of the shoulder, hip, and knee joints were performed. Serum inflammatory mediators and body composition were also evaluated. The total Mankin score for each animal was assessed by adding together the individual Modified Mankin scores across all three joints. Linear regression modelling was conducted to evaluate predictive relationships between serum mediators and total joint damage.

Results

The HFS diet, in the absence of trauma, resulted in increased joint damage in the shoulder and knee joints of rats. Hip joint damage, however, was not significantly affected by DIO, consistent with findings in human studies. The total Mankin score was increased in DIO animals compared with the chow group, and was associated with percentage of body fat. Positive significant predictive relationships for total Mankin score were found between body fat and two serum mediators (interleukin 1 alpha (IL-1α) and vascular endothelial growth factor (VEGF)).

Conclusion

Systemic inflammatory alterations from DIO in this model system may result in a higher risk for development of knee, shoulder, and multi-joint damage with a HFS diet.Cite this article: K. H. Collins, D. A. Hart, R. A. Seerattan, R. A. Reimer, W. Herzog. High-fat/high-sucrose diet-induced obesity results in joint-specific development of osteoarthritis-like degeneration in a rat model. Bone Joint Res 2018;7:274-281. DOI: 10.1302/2046-3758.74.BJR-2017-0201.R2.

Association between the severity of symptomatic knee osteoarthritis and cumulative metabolic factors

BACKGROUND

The association between cumulative metabolic syndrome (MS) factors and knee osteoarthritis (KOA) has been highlighted over the past two decades.

AIMS

To clarify the relationship between cumulative MS factors and symptomatic KOA.

METHODS

A cross-sectional survey involving 119 women aged 45-88 years who were scheduled to undergo knee surgery was conducted. They were stratified into tertiles of symptoms as assessed by the Japanese Orthopedic Association score for KOA. Multinomial logistic regressions were performed using the severity of symptomatic KOA as the dependent variable and each MS factor or the cumulative MS factors as the independent variables.

RESULTS

Logistic regression analyses were performed with the upper tertile of stratified symptoms of subjects used as the reference group. After adjustment for confounders, KOA patients who had two (p = 0.004) or three or more (p < 0.0001) MS factors were significantly more likely to have severe symptoms compared to those who had no MS factors. MS factors excluding obesity were similarly analyzed. Even after additional adjustment for body mass index (BMI), KOA patients who had two or more (p = 0.005) MS factors were significantly more likely to have severe symptoms.

CONCLUSION

Among KOA female patients diagnosed using radiographic definition, the severity of symptomatic KOA was significantly associated with hypertension, dyslipidemia, and the number of MS factors after adjustment for age, BMI, strength of the knee extensor, and Kellgren-Lawrence grade. The severity of radiographic KOA was not associated with any MS factor or cumulative MS factors.

A novel biomarker in patients with knee osteoarthritis: adropin

Adropin is newly discovered peptide hormone. Osteoarthritis (OA) is a kind of joint disease characterized by progressive joint cartilage loss and joint pain. The present study was carried out to investigate adropin and tumor necrosis factor alpha (TNF-α) levels and the relationship between adropin in patients with knee OA classified by Kellgren-Lawrence (KL). A total of 60 knee OA patients and 30 healthy controls were included in this study. KL grading was carried out using the radiographic findings. Demographic characteristics and laboratory parameters were recorded. Adropin and TNF-α levels were determined by using enzyme-linked immunosorbent assay (ELISA). Adropin level was lower in the knee OA patients compared with the healthy controls (p < 0.001), whereas TNF-α level was higher (p < 0.001). Adropin level was negatively correlated with TNF-α level, blood white blood cell (WBC) count, and neutrophil-lymphocyte ratio (NLR). However, there was a significant decrease in adropin level and an increase in TNF-α level parallel to the increase in the KL grade. In addition, serum adropin level was found to be significantly lower in KL grade 1 groups compared with healthy controls (p < 0.01). There was a decrease in adropin level parallel to the increase in the body mass index (BMI), and there was a statistically significant decrease in adropin level in knee OA patients higher than BMI > 30 (p < 0.01). Mean NLR of KL grade 4 was significantly increased compared with other grades (p < 0.05). The consequence of the present study suggested that serum adropin level could be used as a new biomarker indicating the early grade of knee OA.

Association Between Metabolic Syndrome and Radiographic Hand Osteoarthritis: Data From a Community-Based Longitudinal Cohort Study

OBJECTIVE

To explore whether metabolic syndrome and its components are associated with hand osteoarthritis (OA) using longitudinal data from the Framingham Study.

METHODS

Our cross-sectional analyses included 1,089 persons (ages 50-75 years), of whom 785 had longitudinal radiographs obtained 7 years apart. Of these, 586 with no hand OA at baseline were included in analyses of hand OA incidence. We explored associations between metabolic syndrome and its components (central obesity, hypertension, diabetes mellitus, triglyceridemia, and low high-density lipoprotein) and radiographic hand OA (defined as ≥2 interphalangeal joints with a Kellgren/Lawrence [K/L] grade of ≥2) using logistic regression analyses with adjustment for age, sex, and body mass index. In longitudinal analyses, metabolic syndrome was used as a predictor for change in K/L sum score and incident hand OA.

RESULTS

Metabolic syndrome was not associated with the presence of hand OA (odds ratio [OR] 1.11 [95% confidence interval (95% CI) 0.78-1.59]), change in K/L sum score (OR 0.83 [95% CI 0.59-1.17]), or incidence of hand OA (OR 0.91 [95% CI 0.58-1.44]). Hypertension was borderline significantly associated with the presence of hand OA (OR 1.25 [95% CI 0.90-1.74]), and a significant association was found between hypertension and change in K/L sum score (OR 1.47 [95% CI 1.08-1.99]). Consistent dose-response relationships were not demonstrated (data not shown). Furthermore, hypertension was not significantly associated with hand OA incidence (OR 1.23 [95% CI 0.82-1.83]). No significant associations were found between metabolic syndrome and erosive hand OA.

CONCLUSION

We found no association between metabolic syndrome and hand OA. The role of hypertension in hand OA pathogenesis warrants further investigation.

Association between Dietary Glycemic Index and Knee Osteoarthritis: The Korean National Health and Nutrition Examination Survey 2010-2012

BACKGROUND

Obesity and metabolic abnormalities are important risk factors for knee osteoarthritis (KOA). Recent epidemiologic studies have found that a high glycemic index (GI) and glycemic load (GL) diet are associated with a higher risk for metabolic complications and cardiovascular mortality.

OBJECTIVE

We aimed to examine the association between dietary GI, dietary GL, and KOA among Korean adults.

DESIGN

This was a cross-sectional study that analyzed data obtained from the Korean National Health and Nutrition Examination Survey 2010-2012.

PARTICIPANTS/SETTING

A total of 9,203 participants (5,275 women) aged ≥50 years were included.

MAIN OUTCOME MEASURES

KOA was defined as the presence of radiographic features of Kellgren-Lawrence grade ≥2. Chronic knee pain was defined as the presence of knee pain for more than 30 days during the past 3 months. Dietary information was collected using a single 24-hour recall method.

STATISTICAL ANALYSES PERFORMED

The association between the quintiles of dietary GI and dietary GL and knee conditions was analyzed using a multinomial logistic regression analysis adjusting for age, physical activity, obesity, hypertension and diabetes, serum low-density lipoprotein, and total energy intake.

RESULTS

Among the women, the association between dietary GI and symptomatic KOA was: quintile 1: 1.00 (reference); quintile 2: 1.29 (95% CI 0.87 to 1.92); quintile 3: 1.59 (95% CI 1.11 to 2.28); quintile 4: 1.74 (95% CI 1.21 to 2.51); and quintile 5: 1.77 (95% CI 1.20 to 2.60) (P=0.001). Chronic knee pain without KOA was associated with dietary GI; however, this association was not linear across quintiles. There was no significant association between dietary GI and asymptomatic KOA. Among the men, no significant association was found between dietary GI and any knee conditions. There was no significant association between dietary GL and KOA in both men and women.

CONCLUSIONS

There was a significant positive association between dietary GI and symptomatic KOA in women.

Classification of patients with knee osteoarthritis in clinical phenotypes: Data from the osteoarthritis initiative

OBJECTIVES

The existence of phenotypes has been hypothesized to explain the large heterogeneity characterizing the knee osteoarthritis. In a previous systematic review of the literature, six main phenotypes were identified: Minimal Joint Disease (MJD), Malaligned Biomechanical (MB), Chronic Pain (CP), Inflammatory (I), Metabolic Syndrome (MS) and Bone and Cartilage Metabolism (BCM). The purpose of this study was to classify a sample of individuals with knee osteoarthritis (KOA) into pre-defined groups characterized by specific variables that can be linked to different disease mechanisms, and compare these phenotypes for demographic and health outcomes.

METHODS

599 patients were selected from the OAI database FNIH at 24 months' time to conduct the study. For each phenotype, cut offs of key variables were identified matching the results from previous studies in the field and the data available for the sample. The selection process consisted of 3 steps. At the end of each step, the subjects classified were excluded from the further classification stages. Patients meeting the criteria for more than one phenotype were classified separately into a 'complex KOA' group.

RESULTS

Phenotype allocation (including complex KOA) was successful for 84% of cases with an overlap of 20%. Disease duration was shorter in the MJD while the CP phenotype included a larger number of Women (81%). A significant effect of phenotypes on WOMAC pain (F = 16.736 p <0.001) and WOMAC physical function (F = 14.676, p < 0.001) was identified after controlling for disease duration.

CONCLUSION

This study signifies the feasibility of a classification of KOA subjects in distinct phenotypes based on subgroup-specific characteristics.

Metabolic syndrome as a risk factor for total hip or knee replacement due to primary osteoarthritis: a prospective cohort study (the HUNT study and the Norwegian Arthroplasty Register)

Objective

Biochemical changes associated with obesity may accelerate osteoarthritis beyond the effect of mechanical factors. This study investigated whether metabolic syndrome and its components (visceral obesity, hypertension, dyslipidemia and insulin resistance) were risk factors for subsequent total hip replacement (THR) or total knee replacement (TKR) due to primary osteoarthritis.

Design

In this prospective cohort study, data from the second survey of the Nord-Trøndelag Health Study 2 (HUNT2) were linked to the Norwegian Arthroplasty Register for identification of the outcome of THR or TKR. The analyses were stratified by age (<50, 50–69.9 and ≥70 years) and adjusted for gender, body mass index, smoking, physical activity and education.

Results

Of the 62,661 participants, 12,593 (20.1%) were identified as having metabolic syndrome, and we recorded 1,840 (2.9%) THRs and 1,111 (1.8%) TKRs during a mean follow-up time of 15.4 years. Cox regression analyses did not show any association between full metabolic syndrome and THR or TKR, except in persons <50 years with metabolic syndrome who had a decreased risk of THR (hazard ratio [HR] 0.58, 95% CI 0.40–0.83). However, when including only participants whose exposure status did not change during follow-up, this protective association was no longer significant. Increased waist circumference was associated with increased risk of TKR in participants <50 years (HR 1.62, 95% CI 1.10–2.39) and 50–69.9 years (HR 1.43, 95% CI 1.14–1.80). Hypertension significantly increased the risk of TKR in participants <50 years (HR 1.38, 95% CI 1.05–1.81), and this risk was greater for men.

Conclusion

This study found an increased risk of TKR in men <50 years with hypertension and persons <70 years with increased waist circumference. Apart from this, neither metabolic syndrome nor its components were associated with increased risk of THR or TKR due to primary osteoarthritis.

Current and future trends in Russian Rheumatology Care and Research

This short article provides a description of the present state of rheumatology care and research in Russia and discusses opportunities for development and co-operation.

Association between metabolic syndrome and knee osteoarthritis: a cross-sectional study

Background

Osteoarthritis (OA) is the most prevalent chronic joint disease in China. The aim of this study was to examine the association between metabolic syndrome (MetS) and knee OA in a population-based Chinese study.

Methods

Data included in this analysis is from a cross-sectional study, i.e., the Xiangya Hospital Health Management Center Study. MetS was diagnosed according to the criteria defined by the Chinese Diabetes Society. Radiographic knee OA was defined as changes equivalent to Kellgren-Lawrence (K-L) grade 2 or above at least one side. Associations between MetS and its components with OA were evaluated by conducting multivariable adjusted logistic regression.

Results

A total of 5764 participants were included in the present study. The unadjusted OR (1.27, 95%CI: 1.10–1.47, P = 0.001), age-sex adjusted OR (1.17, 95%CI: 1.01–1.36, P = 0.041) and multivariable adjusted OR (1.17, 95%CI: 1.01–1.36, P = 0.043) all suggested a positive association between MetS and knee OA. Besides, its components (e.g., overweight, hypertension and dyslipidemia) were also associated with the prevalence of radiographic knee OA respectively, after adjusting for some confounding factors. In addition, with the accumulation of MetS components, the prevalence of knee OA increased. Furthermore, MetS as a whole was associated with the prevalence of knee osteophyte (OSP) (OR = 1.72, 95%CI: 1.42–2.09, P < 0.001), but not joint space narrowing (JSN) (OR = 1.06, 95%CI: 0.91–1.23, P = 0.449).

Conclusions

The findings of the present study indicated that there was a positive association between the prevalence of MetS and knee OA. However, MetS as a whole was associated with the higher prevalence of knee OSP, but not JSN, which should shed light on our understanding the association between MetS and OA.

Oxidized low density lipoprotein facilitates tumor necrosis factor‑α mediated chondrocyte death via autophagy pathway

We aimed to investigate the role of oxidized low density lipoprotein (ox-LDL) in tumor necrosis factor-α (TNF-α) mediated chondrocyte death and explore the mechanisms. Ten osteoarthritis (OA) and normal control cartilage tissue and synovial fluid (SF) samples were collected, and the expression of lectin-like ox-LDL receptor-1 (LOX-1) and ox-LDL level was examined by real time quantitative PCR and enzyme-linked immunosorbent assay (ELISA). An in vitro chondrocyte model was established by the introduction of TNF-α and ox-LDL, cell death was analyzed by trypan blue assay and the mechanisms were explored based on the apoptosis related pathway and autophagy pathway. Significantly increased ox-LDL level (70.30±17.83 vs. 37.22±19.97, P<0.05) in SF sample and LOX-1 expression level (0.51±0.10 vs. 0.32±0.04, P<0.05) in cartilage tissue was found in OA patients compared to those corresponding samples from control subjects. Ox-LDL could facilitate TNF-α mediated chondrocyte death and this effect could be blocked by LOX-1 antibody neutralization. Autophagy inhibition by 3-MA and Atg-5 siRNA could reverse the cell death effect mediated by TNF-α and ox-LDL co-treatment on chondrocytes. Oxidized low density lipoprotein facilitates tumor necrosis factor-α mediated chondrocyte death via its interaction with LOX-1, and autophagy is involved in the mechanisms.

Statin use and knee osteoarthritis progression: Results from a post-hoc analysis of the SEKOIA trial

OBJECTIVE

Epidemiological and experimental studies have suggested that lipid disorders might be involved in the pathophysiology of knee osteoarthritis (OA). Studies assessing the effect of statins on knee OA progression have shown conflicting results. We investigated the impact of statin use on radiological progression in patients with radiological and symptomatic knee OA.

METHODS

In total, 336 patients from the placebo arm of SEKOIA trial completed the 3-year follow-up and were included in this post-hoc analysis. Statin use was recorded at baseline interview. Minimal medial tibiofemoral joint space was measured on plain radiographs by an automated method at baseline and then annually. Radiologic progression was defined as joint space narrowing≥0.5mm over 3 years.

RESULTS

Overall, 71 patients were statin users (21.1%). They had a higher BMI (31.1±5.3 vs. 29.3±5.2kg/m², P=0.008), a higher sum of metabolic factors (≥3 factors: 43.7% vs 7.2%; P for trend<0.001) and a higher rate of radiological progression (49.3% vs. 32.1%, P=0.007) as compared to statin non-users. The significant association between radiological progression and statin use was independent of age, gender, WOMAC global score, disease duration, baseline joint space width, hypertension, type 2 diabetes, obesity (BMI>30kg/m²) and cardiovascular diseases [relative risk 1.49 (95% CI: 1.10-2.02), P=0.010].

CONCLUSION

Among patients with knee OA, statin use was associated with radiological worsening over 3 years, regardless of other potential confounding factors (obesity, type 2 diabetes, hypertension, disease duration, symptom intensity and radiological severity).

Association between osteoarthritis and dyslipidaemia: a systematic literature review and meta-analysis

OBJECTIVES

We aimed to investigate the prevalence of dyslipidemia in patients with osteoarthritis (OA) and whether OA and dyslipidemia are associated.

METHODS

We performed a systematic literature review and a meta-analysis, including cross-sectional, cohort and case-control studies, to assess the number of patients with OA and/or dyslipidemia. We calculated the mean (±SD) prevalence of dyslipidemia in patients with and without OA and the risk of dyslipidemia (OR, 95% CI) among patients with OA.

RESULTS

From 605 articles screened, 48 were included in the analysis (describing 29 cross-sectional, 10 cohort and 9 case-control studies). The mean prevalence of dyslipidemia was 30.2%±0.6% among 14 843 patients with OA and 8.0%±0.1% among 196 168 without OA. The risk of dyslipidemia was greater with than without OA overall (OR 1.98,95% CI 1.43 to 2.75, p<0.0001) and with knee OA (OR 2.27, 1.33 to 3.89, p=0.003) and hand OA (OR 2.12, 1.46 to 3.07), p<0.0001).

CONCLUSION

The risk of dyslipidemia was twofold greater with than without OA, so lipid disturbances could be a risk factor for OA. Such a result supports the individualisation of the metabolic syndrome-associated OA phenotype.

Association between hypertension and risk of knee osteoarthritis: A meta-analysis of observational studies

Evidence from observational studies shows that hypertension may be a risk factor for knee osteoarthritis (OA). However, the relationship between hypertension and knee OA risk remains controversial. This study aimed to quantitatively assess the relationship between hypertension and risk of knee OA.Three electronic databases (PubMed, Embase, and Cochrane Library) were searched up to July 25, 2016. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were extracted from the included observational studies. Publication bias, heterogeneity test, and subgroup analyses were performed.Eight studies including 2 cohort studies and 6 cross-sectional studies with 9762 participants were finally included in this meta-analysis. The results showed that hypertension was significantly associated with higher radiographic knee OA and symptomatic knee OA risks of 2.01 (95% CI, 1.28-3.15, I = 90.2%, P for heterogeneity <.001) and 1.49 (95% CI, 1.26-1.77, I = 0%, P for heterogeneity <.412), respectively. No publication bias was detected. The subgroup analysis showed that the study design did not influence the results (radiographic knee OA: OR = 1.42, 95% CI, 1.19-1.71 for cross-sectional studies and OR = 2.17, 95% CI, 1.30-3.63 for cohort studies; and symptomatic knee OA: OR = 1.85, 95% CI, 1.10-3.13) for cross-sectional studies and OR = 2.74, 95% CI, 1.81-4.16 for cohort studies).This meta-analysis showed that there was a significant relationship between hypertension and knee OA (both radiographic and symptomatic). However, further original studies are needed that use a better design.

Metabolic syndrome-associated osteoarthritis

PURPOSE OF REVIEW

Interest in the metabolic syndrome-associated osteoarthritis phenotype is increasing. Here, we summarize recently published significant findings.

RECENT FINDINGS

Meta-analyses confirmed an association between type 2 diabetes and osteoarthritis and between cardiovascular diseases and osteoarthritis. Recent advances in the study of metabolic syndrome-associated osteoarthritis have focused on a better understanding of the role of metabolic diseases in inducing or aggravating joint damage. In-vivo models of obesity, diabetes, or dyslipidemia have helped to better decipher this association. They give emerging evidence that, beyond the role of common pathogenic mechanisms for metabolic diseases and osteoarthritis (i.e., low-grade inflammation and oxidative stress), metabolic diseases have a direct systemic effect on joints. In addition to the impact of weight, obesity-associated inflammation is associated with osteoarthritis severity and may modulate osteoarthritis progression in mouse models. As well, osteoarthritis synovium from type 2 diabetic patients shows insulin-resistant features, which may participate in joint catabolism. Finally, exciting data are emerging on the association of gut microbiota and circadian rhythm and metabolic syndrome-associated osteoarthritis.

SUMMARY

The systemic role of metabolic syndrome in osteoarthritis pathophysiology is now better understood, but new avenues of research are being pursued to better decipher the metabolic syndrome-associated osteoarthritis phenotype.

Metabolic Syndrome, Its Components, and Knee Osteoarthritis: The Framingham Osteoarthritis Study

OBJECTIVE

Previous studies have suggested that metabolic syndrome is associated with osteoarthritis (OA). However, analyses have often not included adjustment for body mass index (BMI) and have not addressed whether levels of individual metabolic syndrome components are related to OA. This study was undertaken to examine the relationship of metabolic syndrome and its components with radiographic and symptomatic knee OA.

METHODS

Framingham Study subjects were assessed for OA in 1992-1995 and again in 2002-2005. Near the baseline visit, subjects had components of metabolic syndrome assessed. We defined incident radiographic OA as present when a knee without radiographic OA at baseline had a Kellgren/Lawrence grade of ≥2 at follow-up, and defined incident symptomatic OA as present when a knee developed the new combination of radiographic OA and knee pain. After excluding knees with prevalent OA at baseline, we tested the relationship of metabolic syndrome according to the National Cholesterol Education Program Adult Treatment Panel III criteria and its components with the risk of incident radiographic OA and symptomatic OA before and after adjusting for BMI using the risk ratio from a binary regression with generalized estimating equations.

RESULTS

A total of 991 subjects (55.1% women) with a mean age of 54.2 years were studied, and 26.7% of men and 22.9% of women had metabolic syndrome. Metabolic syndrome and many of its components were associated with both incident radiographic OA and symptomatic OA, but after adjustment for BMI, almost all of these associations became weak and nonsignificant. An association of high blood pressure, especially diastolic pressure, with OA outcomes persisted in both men and women.

CONCLUSION

After adjustment for BMI, neither metabolic syndrome nor its components were associated with incident OA. There may be an association between OA and high blood pressure that needs further study.

Systemic and Local Adipose Tissue in Knee Osteoarthritis

Osteoarthritis is a common chronic joint disorder affecting older people. The knee is the major joint affected. The symptoms of osteoarthritis include limited range of motion, joint swelling, and pain causing disability. There are no disease modifying drugs available, and treatments are mainly focused on pain management. Total knee replacement performed at the end stage of the disease is considered the only cure available. It has been found that obese people have an increased risk to develop not only knee but also hand osteoarthritis. This supports the concept that adipose tissue might be related to osteoarthritis not only through overloading. As matter of fact, obesity induces a low grade systemic inflammatory state characterized by the production and secretion of several adipocytokines that may have a role in osteoarthritis development. Furthermore, hypertension, impaired glucose, and lipid metabolism, which are comorbidities associated with obesity, have been shown to alter the joint tissue homeostasis. Moreover, infrapatellar fat pad in the knee has been demonstrated to be a local source of adipocytokines and potentially contribute to osteoarthritis pathogenesis. Here, we discuss the role of systemic and local adipose tissue in knee osteoarthritis. J. Cell. Physiol. 232: 1971-1978, 2017. © 2016 Wiley Periodicals, Inc.

AGE-RAGE Interaction Does Not Explain the Clinical Improvements after Therapeutic Fasting in Osteoarthritis

BACKGROUND

Therapeutic fasting improves joint pain in patients with osteoarthritis (OA), but the underlying mechanisms are unknown. Interactions of advanced glycation end products (AGEs) and their receptors (RAGE) play a role in OA pathogenesis. This study aimed to investigate whether the benefits of fasting in OA can be explained by changes in AGEs or RAGE.

PATIENTS AND METHODS

37 patients with OA underwent fasting for 8 days. Serum levels of an AGE (N-ε-(carboxymethyl)-lysine; CML) and the soluble RAGE (sRAGE) as well as clinical outcome parameters such pain characteristics (measured by visual analogue scale; VAS), joint function (determined by the Western Ontario and McMaster Universities Arthritis Index; WOMAC), and quality of life (via the 36-Item Short-Form Health Survey (SF-36) questionnaire) were assessed. The variables were measured at baseline, the end of fasting, and at follow-up at 4 weeks.

RESULTS

The CML levels did not significantly change from baseline to the end of intervention (Δ = -25.6 ± 92.2 ng/ml; p = 0.10). In contrast, the sRAGE levels (Δ = -182.7 ± 171.4 ng/ml; p < 0.0001) and the sRAGE/CML ratio (Δ = -0.4 ± 0.6; p < 0.001) significantly decreased, but they returned to baseline levels 4 weeks after the end of fasting. The scores for pain, WOMAC, and the physical subscale of the SF-36 significantly improved during fasting. There was no correlation between the clinical outcomes and changes in serum levels of CML, sRAGE, or the sRAGE/CML ratio.

CONCLUSIONS

Fasting resulted in a significant but non-sustained reduction of sRAGE levels and the sRAGE/CML ratio in OA, while the CML levels did not change. Improvement in clinical endpoints of OA does not correlate with changes in CML or sRAGE.

Exploratory analysis of osteoarthritis progression among medication users: data from the Osteoarthritis Initiative

BACKGROUND

We conducted an exploratory analysis of osteoarthritis progression among medication users in the Osteoarthritis Initiative to identify interventions or pathways that may be associated with disease modification and therefore of interest for future clinical trials.

METHODS

We used participants from the Osteoarthritis Initiative with annual medication inventory data between the baseline and 36-month follow-up visit (n = 2938). Consistent medication users were defined for each medication classification as a participant reporting at all four annual visits that they were regularly using an oral prescription medication at the time of the visit. The exploratory analysis focused on medication classes with 40 or more users. The primary outcome measures were medial tibiofemoral joint space width change and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee pain score change (12-36-month visits). Within each knee, we explored eight comparisons between users and matched or unmatched nonusers (defined two ways). An effect size of each comparison was calculated. Medication classes had potential signals if (a) both knees had less progression among users compared with nonusers, or (b) there was less progression based on structure and symptoms in one knee.

RESULTS

We screened 28 medication classes. Six medication classes had signals for fewer structural changes and better knee pain changes: alpha-adrenergic blockers, antilipemic (excluding statins and fibric acid), anticoagulants, selective serotonin reuptake inhibitors, antihistamines, and antineoplastic agents. Four medication classes had signals for structural changes alone: anti-estrogen (median effect size = 0.28; range = -0.41-0.64), angiotensin-converting enzyme inhibitors (median effect size = 0.13; range = -0.08-0.28), beta-adrenergic blockers (median effect size = 0.09; range = 0.01-0.30), and thyroid agents (median effect size = 0.04; range = -0.05-0.14). Thiazide diuretics had evidence for symptom modification (median effect size = -0.12; range = -0.24-0.04).

CONCLUSIONS

Users of neurovascular, antilipemic, or hormonal interventions may have less disease progression compared with nonusers.

Emerging role of metabolic signaling in synovial joint remodeling and osteoarthritis

Obesity and associated metabolic diseases collectively referred to as the metabolic syndrome increase the risk of skeletal and synovial joint diseases, including osteoarthritis (OA). The relationship between obesity and musculoskeletal diseases is complex, involving biomechanical, dietary, genetic, inflammatory, and metabolic factors. Recent findings illustrate how changes in cellular metabolism and metabolic signaling pathways alter skeletal development, remodeling, and homeostasis, especially in response to biomechanical and inflammatory stressors. Consequently, a better understanding of the energy metabolism of diarthrodial joint cells and tissues, including bone, cartilage, and synovium, may lead to new strategies to treat or prevent synovial joint diseases such as OA. This rationale was the basis of a workshop presented at the 2016 Annual ORS Meeting in Orlando, FL on the emerging role of metabolic signaling in synovial joint remodeling and OA. The topics we covered included (i) the relationship between metabolic syndrome and OA in clinical and pre-clinical studies; (ii) the effect of biomechanical loading on chondrocyte metabolism; (iii) the effect of Wnt signaling on osteoblast carbohydrate and amino acid metabolism with respect to bone anabolism; and (iv) the role of AMP-activated protein kinase in chondrocyte energetic and biomechanical stress responses in the context of cartilage injury, aging, and OA. Although challenges exist for measuring in vivo changes in synovial joint tissue metabolism, the findings presented herein provide multiple lines of evidence to support a central role for disrupted cellular energy metabolism in the pathogenesis of OA. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2048-2058, 2016.

Osteoarthritis and type 2 diabetes mellitus: What are the links?

Osteoarthritis (OA) is the most frequent joint disorder and one of the leading cause of disability. During a long time, it was considered as the consequence of aging and mechanical stress on cartilage. Recent advances in the knowledge of OA have highlighted that it is a whole joint disease with early modifications of synovium and subchondral bone but also that it is associated with obesity and metabolic syndrome through systemic mechanisms. In the past year, type 2 diabetes has been described in two meta-analyzes as an independent risk factor for OA. In vivo models of diabetes corroborated epidemiological studies. Indeed, diabetic rodents display a spontaneous and a more severe experimental OA than their non-diabetic counterparts, which can be partially prevented by diabetes treatment (insulin, pioglitazone). The negative impact of diabetes on joints could be explain by the induction of oxidative stress and pro-inflammatory cytokines but also by advanced age products accumulation in joint tissues exposed to chronic high glucose concentration. Insulin resistance might also impair joint tissue because of a local insulin resistance of diabetic synovial membrane but also by the systemic low grade inflammation state related to obesity and insulin resistant state.

Clinical Factors, Disease Parameters, and Molecular Therapies Affecting Osseointegration of Orthopedic Implants

Total hip and knee arthroplasty are effective interventions for management of end-stage arthritis. Indeed, about 7 million Americans are currently living with artificial hip and knee joints. The majority of these individuals, however, will outlive their implants and require revision surgeries, mostly due to poor implant osseointegration and aseptic loosening. Revisions are potentially avoidable with better management of patient-related risk factors that affect the osseointegration of orthopedic implants. In this review, we summarize the published clinical literature on the role of demographics, biologic factors, comorbidities, medications and aseptic loosening risk. We focus on several systemic and local factors that are particularly relevant to implant osseointegration. Examples include physiological and molecular processes that are linked to hyperglycemia, oxidative stress, metabolic syndrome and dyslipidemia. We discuss how orthopedic implant osseointegration can be affected by a number of molecular therapies that are antiresorptive or bone anabolic (i.e. calcium, vitamin D, bisphosphonates, calcitonin, strontium, hormone replacement therapy, selective estrogen-receptor modulators).

Type II diabetes mellitus and incident osteoarthritis of the hand: a population-based case-control analysis

OBJECTIVES

Emerging evidence suggests that diabetes may be a risk factor for osteoarthritis (OA). However, previous results on the association between diabetes and all OA were conflicting. We aimed to comprehensively analyse the association between type II diabetes mellitus (T2DM) and osteoarthritis of the hand (HOA) specifically.

METHODS

We conducted a matched (1:1) case-control study using the UK-based Clinical Practice Research Datalink (CPRD) of cases aged 30-90 years with an incident diagnosis of HOA from 1995 to 2013. In multivariable conditional logistic regression analyses, we calculated odds ratios (OR) for incident HOA in patients with T2DM, categorized by T2DM severity (HbA1C), duration, and pharmacological treatment. We further performed sensitivity analyses in patients with and without other metabolic diseases (hypertension (HT), hyperlipidaemia (HL), obesity).

RESULTS

Among 13,500 cases and 13,500 controls, we observed no statistically significant association between T2DM and HOA (OR 0.95, 95% confidence interval (CI) 0.87-1.04), regardless of T2DM severity, duration, or pharmacological treatment. Having HT did not change the OR. Although we observed slightly increased ORs in overweight T2DM patients with co-occurring HL with or without coexisting HT, none of these ORs were statistically significant.

CONCLUSIONS

Our results provide evidence that T2DM is not an independent risk factor for HOA. Concurrence of T2DM with HT, HL, and/or obesity did not change this association significantly.

Factors associated with diagnostic stage of hip osteoarthritis due to acetabular dysplasia among Japanese female patients: a cross-sectional study

Background

In Japan, the majority of hip osteoarthritis (OA) was caused by acetabular dysplasia, and about 90 % of patients were female. The present study focused on Japanese female patients with hip OA due to acetabular dysplasia, and examined the associated factors with OA staging at diagnosis, in special reference to body weight.

Methods

Study subjects were 336 Japanese women who were newly diagnosed with hip OA caused by acetabular dysplasia at 15 hospitals in 2008. The self-administered questionnaire elicited patients’ body weight at age 20 and at OA diagnosis. Four ranked OA staging according to radiographic findings of the hip joint (pre-OA, initial stage, advanced stage or terminal stage) was regarded as the outcome index. Proportional odds models in logistic regression were used to calculate odds ratios (ORs) and 95 % confidence intervals (CIs) for severer stage of OA.

Results

At diagnosis, 45 % of patients suffered from terminal stage of OA, whereas 13 % and 14 % were categorized into pre-OA and initial stage, respectively. After adjustment for potential confounders, weight gain since age 20 revealed the increased ORs for severer OA stage at diagnosis (OR 2.02; 95 % CI, 1.07–3.80). Other significant characteristics were age (67+ vs. 20–49 years, OR 12.4), lower education (junior high school vs. junior college or higher, OR 4.00), parity (OR 2.19), lower acetabular head index (<60.0 vs. 71.1+, OR 2.36), and longer duration since symptom onset (6.0+ vs. <1.0 year, OR 2.94).

Conclusions

Weight gain since age 20 might be involved in mechanisms of OA development, which is independent of age or severity of acetabular dysplasia.

Obesity in early adulthood predicts knee pain and walking difficulties among men: A life course study

BACKGROUND

Few studies have addressed the role of obesity in young adulthood in knee problems later in life. We assessed the associations of overweight/obesity with knee pain and functional limitations of the knee across the life course.

METHODS

Military health records from 1967 to 2000 (baseline) were searched for 18- to 50-year-old Finnish men (n = 1913) who participated in the Health 2000 Study (follow-up). Visits to health care were followed during service. Height and weight were measured at baseline and follow-up and waist circumference at follow-up. Weight was inquired at follow-up for ages of 20, 30, 40 and 50 years, if applicable. Life course body mass index (BMI) was calculated. One-month knee pain and functional limitations (walking difficulties and limping) due to knee problems were enquired with interview at follow-up. Cox regression model, logistic regression and trajectory analysis were applied.

RESULTS

Body mass index at the age of 20 increased the risk of unilateral knee pain by 38% and functional limitations by 27% for one standard deviation increment of BMI, respectively. One-unit increment of Z-score of life course BMI increased knee pain by 32%. Development of severe obesity during the follow-up increased the risk of knee pain by 80% and functional limitations by 93%. The effect of obesity on functional limitations was partly mediated by traumatic knee problems during military service.

CONCLUSIONS

Reducing overweight already in adolescence and avoiding further weight gain during life course may prevent knee pain and associated disability. WHAT DOES THIS STUDY ADD?: BMI at the age of 20 increases the likelihood of knee pain and functional limitations of the knee later in life. Development of severe obesity in adulthood increases the risk of knee pain by 80% and functional limitations by more than 90%. Both general and abdominal obesity are associated with knee pain, associations being stronger for general obesity.

The relationship between smoking and knee osteoarthritis in the Osteoarthritis Initiative

OBJECTIVE

To estimate the extent that smoking history is associated with symptoms and disease progression among individuals with radiographically confirmed knee Osteoarthritis (OA).

METHOD

Both cross-sectional (baseline) and longitudinal studies employed data from the Osteoarthritis Initiative (OAI) (n = 2250 participants). Smoking history was assessed at baseline with 44% current or former smokers. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used to measure knee pain, stiffness, and physical function. Disease progression was measured using joint space width (JSW). We used adjusted multivariable linear models to examine the relationship between smoking status and exposure in pack years (PY) with symptoms and JSW at baseline. Changes in symptoms and JSW over time were further assessed.

RESULTS

In cross-sectional analyses, compared to never-smokers high PY (≥15 PY) was associated with slightly greater pain (beta 0.36, 95% CI: 0.01-0.71) and stiffness (beta 0.20, 95% CI: 0.03-0.37); and low PY (<15 PY) was associated with better JSW (beta 0.15, 95% CI: 0.02-0.28). Current smoking was associated with greater pain (beta 0.59, 95% CI: 0.04-1.15) compared to never-smokers. These associations were not confirmed in the longitudinal study. Longitudinally, no associations were found between high or low PY or baseline smoking status with changes in symptoms (at 72 months) or JSW (at 48 months).

CONCLUSION

Cross-sectional findings are likely due residual confounding. The more robust longitudinal analysis found no associations between smoking status and symptoms or JSW. Long-term smoking provides no benefits to knee OA patients while exposing them to other well-documented serious health risks.

Association of Objectively Measured Physical Activity and Metabolic Syndrome Among US Adults With Osteoarthritis

OBJECTIVE

To investigate the association between objectively measured physical activity and metabolic syndrome among adults with osteoarthritis (OA).

METHODS

Using cross-sectional data from the 2003-2006 National Health and Nutrition Examination Survey, we identified 566 adults with OA with available accelerometer data assessed using Actigraph AM-7164 and measurements necessary to determine metabolic syndrome by the Adult Treatment Panel III. Analysis of variance was conducted to examine the association between continuous variables in each activity level and metabolic syndrome components. Logistic models estimated the relationship of quartile of daily minutes of different physical activity levels to odds of metabolic syndrome adjusted for socioeconomic and health factors.

RESULTS

Among persons with OA, most were women average age of 62.1 years and average disease duration of 12.9 years. Half of adults with OA had metabolic syndrome (51.0%; 95% confidence interval [95% CI] 44.2%-57.8%), and only 9.6% engaged in the recommended 150 minutes per week of moderate/vigorous physical activity. Total sedentary time was associated with higher rates of metabolic syndrome and its components, while light and objectively measured moderate/vigorous physical activity was inversely associated with metabolic syndrome and its components. Higher levels of light activity were associated with lower prevalence of metabolic syndrome (quartile 4 versus quartile 1: adjusted odds ratio 0.45, 95% CI 0.24-0.84, P for linear trend < 0.005).

CONCLUSION

Most US adults with OA are sedentary. Increased daily minutes in physical activity, especially in light intensity, is more likely to be associated with decreasing prevalence of metabolic syndrome among persons with OA.

Inter-relations between osteoarthritis and metabolic syndrome: A common link?

Osteoarthritis (OA) is a degenerative disorder of the joint, principally occurring during aging, and characterized by a focal degradation of cartilage. It is the most prevalent rheumatic disease in industrialized countries and represents the second cause of disability in France. However, the etiology of OA remains unclear. There is only one cell type found in cartilage, chondrocyte, which is responsible for its repair and the synthesis of the elements of the extra-cellular matrix. A dysfunction of these cells results in an imbalance between repair and degradation in cartilage, leading to its destruction. Recently, a link between OA and metabolic syndrome (MetS) has been suggested, introducing a notion of metabolic OA, and a new vision of the disease. MetS is characterized by a cluster of factors (insulin resistance, hypertension, dyslipidemia, visceral obesity), although there is still no clear definition of it. During the 20th century, MetS dramatically increased with changes in population lifestyle, becoming a major health issue in industrialized countries. MetS concerns 10-30% of the worldwide population, but is prevalent in 59% of OA patients. Patients with both OA and MetS have more severe symptoms, occurring sooner than in the general population. Indeed, OA is generally a disease concerning the population over 65 years old, but with an associated MetS the target population is around 50 years old. In this review, we will focus on common factors in OA and MetS, such as hypertension, obesity, dyslipidemia, mitochondrial dysfunction and hyperglycemia, linking one disease to the other.

Metabolic stress-induced joint inflammation and osteoarthritis

Osteoarthritis (OA) is a heterogeneous disorder with several risk factors. Among them, obesity has a major impact on both loading and non-loading joints. Mechanical overload and activity of systemic inflammatory mediators derived from adipose tissue (adipokines, free fatty acids (FFA), reactive oxygen species (ROS)) provide clues to the increased incidence and prevalence of OA in obesity. Recently, research found greater OA prevalence and incidence in obese patients with cardiometabolic disturbances than "healthy" obese patients, which led to the description of a new OA phenotype - metabolic syndrome (MetS)-associated OA. Indeed, individual metabolic factors (diabetes, dyslipidemia, and hypertension) may increase the risk of obesity-induced OA. This review discusses hypotheses based on pathways specific to a metabolic factor in MetS-associated OA, such as the role of advanced glycation end products (AGEs) and glucose toxicity. A better understanding of these phenotypes based on risk factors will be critical for designing trials of this specific subset of OA.

Is osteoarthritis a metabolic disorder?

BACKGROUND

Obesity is associated with an increased risk of developing osteoarthritis (OA), even in non-weight bearing joints. High levels of adipose tissue-associated inflammation may explain this association.

SOURCES OF DATA AND AREAS OF DEBATE

Published evidence looking at the associations between components of Metabolic Syndrome (MetS) and knee, hip or hand OA and the higher mortality described with knee OA.

EMERGING POINTS

Development of MetS and OA shares a relationship with adipose tissue-associated inflammation. This review supports this inflammatory pathway being part of the shared mechanism behind obesity as a risk factor for OA and the recently described OA-associated increased mortality.

TIMELY AREAS FOR DEVELOPMENT

In an era of an obesity epidemic, this review identifies a need for well-designed cohort studies assessing early metabolic changes in populations at high risk of OA and MetS, and to identify risk factors for increased mortality in patients with OA.

Behavioural physical activity interventions in participants with lower-limb osteoarthritis: a systematic review with meta-analysis

OBJECTIVE

To assess effectiveness of osteoarthritis interventions to promote long-term physical activity behaviour change.

DESIGN

A systematic review and meta-analysis. Protocol registration PROSPERO CRD4201300444 5 (http://www.crd.york.ac.uk/prospero/).

STUDY SELECTION

Randomised controlled trials (RCTs) comparing physical activity interventions with placebo, no/or minimal intervention in community-dwelling adults with symptomatic knee or hip osteoarthritis. Primary outcomes were change in physical activity or cardiopulmonary fitness after a minimum follow-up of 6 months.

DATA EXTRACTION

Outcomes were measures of physical activity (self-reported and objectively measured) and cardiovascular fitness. Standard mean differences between postintervention values were used to describe the effect sizes.

RESULTS

27,984 titles were screened and 180 papers reviewed in full. Eleven RCTs satisfied inclusion criteria, total study population of 2741 participants, mean age 62.2. The commonest reasons for study exclusion were follow-up less than 6 months and no physical activity measures. The majority of included interventions implement an arthritis self-management programme targeting coping skills and self-efficacy. Seven studies used self-report measures, the pooled effect of these studies was small with significant heterogeneity between studies (SMD 0.22 with 95% CI -0.11 to 0.56, z=1.30 (p=0.19) I(2) statistic of 85%). Subgroup analysis of 6-12 month outcome reduced heterogeneity and increased intervention effect compared to control (SMD 0.53, 95% CI 0.41 to 0.65, z=8.84 (p<0.00001) I(2) of 66%).

CONCLUSIONS

Arthritis self-management programmes achieve a small but significant improvement in physical activity in the short term. Effectiveness of intervention declines with extended follow-up beyond 12 months with no significant benefit compared to control. The small number of studies (11 RCTs) limited ability to define effective delivery methods. Investigation of behavioural lifestyle interventions for lower limb osteoarthritis populations would benefit from consensus on methodology and outcome reporting. This includes use of validated physical activity reporting tools and planning for long-term follow-up.

Association of low birth weight and preterm birth with the incidence of knee and hip arthroplasty for osteoarthritis

OBJECTIVE

Low birth weight (LBW) and preterm birth have been associated with adverse adult outcomes, including hypertension, insulin resistance, cardiovascular disease, and reduced bone mass. It is unknown whether LBW and preterm birth affect the risk of osteoarthritis (OA). This study aims to examine whether LBW and preterm birth were associated with the incidence of knee and hip arthroplasty for OA.

METHODS

A total of 3,604 participants of the Australian Diabetes, Obesity and Lifestyle Study who reported their birth weight and history of preterm birth and were age >40 years at the commencement of arthroplasty data collection comprised the study sample. The incidence of knee and hip replacement for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.

RESULTS

One hundred and sixteen participants underwent knee arthroplasty and 75 underwent hip arthroplasty for OA. LBW (yes versus no; hazard ratio [HR] 2.04, 95% confidence interval [95% CI] 1.11-3.75, P = 0.02) and preterm birth (yes versus no; HR 2.50, 95% CI 1.29-4.87, P = 0.007) were associated with increased incidence of hip arthroplasty independent of age, sex, body mass index, education level, hypertension, diabetes mellitus, smoking, and physical activity. No significant association was observed for knee arthroplasty.

CONCLUSION

Although these findings will need to be confirmed, they suggest that individuals born with LBW or at preterm are at increased risk of hip arthroplasty for OA in adult life. The underlying mechanisms warrant further investigation.

Weight change following knee and hip joint arthroplasty-a six-month prospective study of adults with osteoarthritis

Background

Inconsistent findings of weight change following total knee (TKA) and hip (THA) arthroplasty may largely be attributable to heterogeneous cohorts and varied definitions of weight loss. This study examined weight change following TKA and THA for osteoarthritis (OA).

Methods

64 participants with hip or knee OA were recruited from orthopaedic joint arthroplasty waiting lists at a single major Australian public hospital between March and October 2011. The Short Form (SF) 12 survey was used to assess baseline physical and mental functioning. 49 participants completed 6 month follow-up (20 from the THA group and 29 from the TKA group).

Results

The majority of subjects lost weight (>0 kg) 6 months following THA (70 %) and TKA (58.6 %). When at least a 5 % reduction in total body weight was used to define clinically significant weight loss, the proportion of people with weight loss was 37.9 % for TKA and 25 % for THA. Greater weight loss occurred 6 months following TKA compared with THA (7.2 % versus 3.7 % of body weight; p = 0.04). Worse pre-operative physical functioning (SF-12) was associated with greater weight loss following TKA (β = 0.22 kg, 95 % CI 0.02-0.42 kg; p = 0.04).

Conclusion

Most people lost weight (>0 kg) 6 months following TKA and THA and a considerable proportion of people achieved ≥5 % loss of body weight. The magnitude of weight loss was greater following TKA than THA, with worse pre-operative function being a predictor of more weight loss. Further attention to weight management is required to assist a greater number of people to achieve a larger magnitude of weight loss following knee and hip joint arthroplasty.

Diabetes is a risk factor for knee osteoarthritis progression

PURPOSE

Recent studies have suggested that metabolic factors (obesity, diabetes, hypertension and dyslipidemia) and their clustering in metabolic syndrome (MetS) might be involved in the pathophysiology of knee osteoarthritis (OA). We investigated their impact on radiographic progression by an annualised measure of the joint space narrowing (JSN) of the medial tibiofemoral compartment.

METHODS

559 patients older than 50 years with symptomatic knee OA were recruited for the placebo arm of the SEKOIA trial. The presence of diabetes, hypertension and dyslipidemia was determined at baseline interview. Body mass index (BMI) was calculated, obesity was considered >30 kg/m(2). MetS was defined by the sum of metabolic factors ≥ 3. Minimal medial tibiofemoral joint space on plain radiographs was measured by an automated method at baseline and then annually for up to 3 years.

RESULTS

The mean age of patients was 62.8 [62.2-63.4] years; 392 were women. A total of 43.8% was obese, 6.6% had type 2 diabetes, 45.1% hypertension, 27.6% dyslipidemia and 13.6% MetS. Mean annualised JSN was greater for patients with type 2 diabetes than without diabetes (0.26 [-0.35 to -0.17] vs 0.14 [-0.16 to -0.12] mm; P = 0.001). This association remained significant after adjustment for sex, age, BMI, hypertension and dyslipidemia (P = 0.018). In subgroup analysis, type 2 diabetes was a significant predictor of JSN in males but not females. The other metabolic factors and MetS were not associated with annualised JSN.

CONCLUSION

Type 2 diabetes was a predictor of joint space reduction in men with established knee OA. No relationships were found between MetS or other metabolic factors and radiographic progression.

Retinal arteriolar narrowing and incidence of knee replacement for osteoarthritis: a prospective cohort study

OBJECTIVES

The role of the microcirculation in the pathogenesis of osteoarthritis (OA) remains unclear. This prospective cohort study examined the association between retinal vascular calibre and incidence of knee replacement for OA.

DESIGN

1838 participants of the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study had retinal vascular calibre measured using a nonmydriatic digital fundus camera in 1999-2000 and were aged ≥ 40 years at joint replacement data collection commencement. The incidence of knee replacement for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).

RESULTS

77 participants underwent knee replacement for OA. They had narrower retinal arteriolar calibre compared with those without knee replacement (166.1 ± 24.8 μm vs 174.3 ± 24.5 μm, P = 0.004). For every one standard deviation reduction in retinal arteriolar calibre, the incidence of knee replacement increased by 25% (HR 1.25, 95% confidence interval (CI) 1.00-1.56). Participants in the narrower two-thirds of arteriolar calibre had twice the risk of knee replacement compared with those in the widest one-third (HR 2.00, 95% CI 1.07-3.74, P = 0.03) after adjustment for sex, body mass index (BMI), physical activity and HbA1c. There was no association for retinal venular calibre.

CONCLUSIONS

Retinal arteriolar narrowing is associated with increased risk of knee replacement for OA suggesting that further work is warranted to determine the role of the microcirculation in the pathogenesis of knee OA.

An educational review of cartilage repair: precepts & practice--myths & misconceptions--progress & prospects

OBJECTIVE

The repair of cartilaginous lesions within synovial joints is still an unresolved and weighty clinical problem. Although research activity in this area has been indefatigably sustained, no significant progress has been made during the past decade. The aim of this educational review is to heighten the awareness amongst students and scientists of the basic issues that must be tackled and resolved before we can hope to escape from the whirlpool of stagnation into which we have fallen: cartilage repair redivivus!

DESIGN

Articular-cartilage lesions may be induced traumatically (e.g., by sports injuries and occupational accidents) or pathologically during the course of a degenerative disease (e.g., osteoarthritis). This review addresses the biological basis of cartilage repair and surveys current trends in treatment strategies, focussing on those that are most widely adopted by orthopaedic surgeons [viz., abrasive chondroplasty, microfracturing/microdrilling, osteochondral grafting and autologous-chondrocyte implantation (ACI)]. Also described are current research activities in the field of cartilage-tissue engineering, which, as a therapeutic principle, holds more promise for success than any other experimental approach.

RESULTS AND CONCLUSIONS

Tissue engineering aims to reconstitute a tissue both structurally and functionally. This process can be conducted entirely in vitro, initially in vitro and then in vivo (in situ), or entirely in vivo. Three key constituents usually form the building blocks of such an approach: a matrix scaffold, cells, and signalling molecules. Of the proposed approaches, none have yet advanced beyond the phase of experimental development to the level of clinical induction. The hurdles that need to be surmounted for ultimate success are discussed.

Structural changes of hip osteoarthritis using magnetic resonance imaging

INTRODUCTION

Few data are available concerning structural changes at the hip observed by magnetic resonance imaging (MRI) in people with or without hip osteoarthritis (OA). The aim of this study was to compare cartilage volume and the presence of cartilage defects and bone marrow lesions (BMLs) in participants with and without diagnosed hip OA.

METHODS

Femoral head cartilage volume was measured by MRI for 141 community-based persons with no diagnosed hip OA, and 19 with diagnosed hip OA. Cartilage defects and BMLs were regionally scored at the femoral head and acetabulum.

RESULTS

Compared with those without diagnosed hip OA, people with diagnosed hip OA had less femoral head cartilage volume (1763 mm3 versus 3343 mm3; p < 0.001) and more prevalent cartilage defects and BMLs (all p ≤ 0.05) at all sites other than the central inferomedial region of the femoral head. In those with no diagnosed hip OA, cartilage defects in the anterior and central superolateral region of the femoral head were associated with reduced femoral head cartilage volume (all p ≤ 0.02). Central superolateral BMLs at all sites were associated with reduced femoral head cartilage volume (all p ≤ 0.003), with a similar trend occurring when BMLs were located in the anterior region of the hip (all p ≤ 0.08).

CONCLUSIONS

Compared with community-based adults with no diagnosed hip OA, people with diagnosed hip OA have less femoral head cartilage volume and a higher prevalence of cartilage defects and BMLs. For people with no diagnosed hip OA, femoral head cartilage volume was reduced where cartilage defects and/or BMLs were present in the anterior and central superolateral regions of the hip joint. Cartilage defects and BMLs present in the anterior and central superolateral regions may represent early structural damage in the pathogenesis of hip OA.

Incidence of total knee and hip replacement for osteoarthritis in relation to circulating sex steroid hormone concentrations in women

OBJECTIVE

The increased prevalence of osteoarthritis (OA) in postmenopausal women suggests that changes in either circulating sex steroid concentrations or the tissue response to sex steroids may have a role in the pathogenesis of OA. The aim of this study was to examine whether circulating sex steroid concentrations are associated with the incidence of total knee and total hip replacement for OA.

METHODS

Study subjects (n = 2,621; all women) were recruited in 1990-1994 from the Melbourne Collaborative Cohort Study (MCCS). Circulating sex steroid concentrations were measured in blood samples obtained from the women at the time of recruitment. The incidence of total knee and total hip replacement for OA during 2001-2011 was determined by linking the MCCS records to the Australian Orthopaedic Association National Joint Replacement Registry.

RESULTS

During the followup period, 115 women had undergone total knee replacement and 99 had undergone total hip replacement for OA. Greater log-transformed concentrations of estradiol were associated with a lower incidence of knee replacement (hazard ratio [HR] 0.70, 95% confidence interval [95% CI] 0.50-0.96), and greater log-transformed concentrations of androstenedione were associated with a lower incidence of hip replacement (HR 0.70, 95% CI 0.52-0.93). In contrast, greater log-transformed concentrations of sex hormone binding globulin (SHBG) were associated with a higher incidence of hip replacement (HR 1.70, 95% CI 1.05-2.77).

CONCLUSION

A lower estradiol concentration is a risk factor for knee OA, while a lower androstenedione concentration and higher SHBG concentration are risk factors for hip OA in women. These findings suggest that circulating sex steroids have a role in the pathogenesis of OA, and that modifying these steroid concentrations may provide a potential strategy for the prevention and treatment of knee and hip OA.

Association between metabolic syndrome, radiographic knee osteoarthritis, and intensity of knee pain: results of a national survey

CONTEXT

Although osteoarthritis (OA) has been suggested as another component of metabolic syndrome (MetS), weight-independent associations between MetS and knee OA or intensity of arthritic knee pain remain unclear.

OBJECTIVE

The objective of the study was to evaluate the above associations and suggest possible mechanisms.

DESIGN AND SETTING

This was a cross-sectional study using the fifth Korean National Health and Nutrition Examination Survey (2010).

PARTICIPANTS

A total of 2363 adults (≥50 y of age) who had completed both laboratory examinations and an evaluation for radiographic knee OA participated in the study.

MAIN OUTCOME AND MEASURES

Radiographic knee OA was defined as a Kellgren/Lawrence grade of 2 or greater, and the intensity of arthritic knee pain was assessed using a self-reported numeric rating scale. MetS was diagnosed based on National Cholesterol Education Program-Adult Treatment Panel III criteria, and insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance index.

RESULTS

In a multivariable logistic regression analysis, MetS was associated with radiographic knee OA (adjusted odds ratio 1.49; 95% confidence interval 1.23-1.79; P < .001). This association was not changed significantly after further adjusting for homeostasis model assessment-estimated insulin resistance but became nonsignificant after adjusting for weight or body mass index. Age-, sex-, and weight (or body mass index)-adjusted mean score of knee pain was significantly higher in subjects with more components of MetS (P for trend = .010 or .035, respectively).

CONCLUSIONS

The association between MetS and radiographic knee OA can be largely explained by an excessive weight but not by insulin resistance, a key pathophysiology of MetS. Because accumulation of MetS components appears to be associated with a higher intensity of knee pain, independently of weight, appropriate treatment for MetS may be helpful for subjects with knee pain.

Determinants of MSK health and disability: lifestyle determinants of symptomatic osteoarthritis

It is frequently considered that, for many people, symptomatic osteoarthritis involving the lower limb joints is a largely preventable 'lifestyle disease'. The purpose of this review is to evaluate the most recent scientific evidence examining the effect of various lifestyle factors, such as physical activity, obesity, diet, smoking, alcohol and injury, on the development of symptomatic knee or hip osteoarthritis. The strengths and weaknesses of various studies are discussed, the magnitude of any demonstrated risks presented and current overall conclusions drawn.