Differences in radiographic features of knee osteoarthritis in African-Americans and Caucasians: the Johnston county osteoarthritis project

Looking back on 30+ years of the Johnston County Osteoarthritis Project while looking forward with the Johnston County Health Study: A narrative review

Over the last 30 years, knowledge of the epidemiology of osteoarthritis (OA) has dramatically advanced, and Osteoarthritis and Cartilage has been on the forefront of disseminating research findings from large OA cohort studies, including the Johnston County OA Project (JoCoOA). The JoCoOA is a population-based, prospective longitudinal cohort that began roughly 30 years ago with a key focus on understanding prevalence, incidence, and progression of OA, as well as its risk factors, in a predominantly rural population of Black and White adults 45+ years old in a county in the southeastern United States. Selected OA results that will be discussed in this review include racial differences, lifetime risk, biomarkers, mortality, and OA risk factors. The new Johnston County Health Study will also be introduced. This new cohort study of OA and comorbid conditions builds upon current OA knowledge and JoCoOA infrastructure and is designed to reflect changes in demographics and urbanization in the county and the region.

Patterns of variation among baseline femoral and tibial cartilage thickness and clinical features: Data from the osteoarthritis initiative

Objective

To employ novel methodologies to identify phenotypes in knee OA based on variation among three baseline data blocks: 1) femoral cartilage thickness, 2) tibial cartilage thickness, and 3) participant characteristics and clinical features.

Methods

Baseline data were from 3321 Osteoarthritis Initiative (OAI) participants with available cartilage thickness maps (6265 knees) and 77 clinical features. Cartilage maps were obtained from 3D DESS MR images using a deep-learning based segmentation approach and an atlas-based analysis developed by our group. Angle-based Joint and Individual Variation Explained (AJIVE) was used to capture and quantify variation, both shared among multiple data blocks and individual to each block, and to determine statistical significance.

Results

Three major modes of variation were shared across the three data blocks. Mode 1 reflected overall thicker cartilage among men, those with higher education, and greater knee forces; Mode 2 showed associations between worsening Kellgren-Lawrence Grade, medial cartilage thinning, and worsening symptoms; and Mode 3 contrasted lateral and medial-predominant cartilage loss associated with BMI and malalignment. Each data block also demonstrated individual, independent modes of variation consistent with the known discordance between symptoms and structure in knee OA and reflecting the importance of features such as physical function, symptoms, and comorbid conditions independent of structural damage.

Conclusions

This exploratory analysis, combining the rich OAI dataset with novel methods for determining and visualizing cartilage thickness, reinforces known associations in knee OA while providing insights into the potential for data integration in knee OA phenotyping.

Disparities Exist in Physical Therapy Utilization and Time to Utilization Between Black and White Patients With Musculoskeletal Pain

OBJECTIVE

Black patients are less likely than White patients to receive physical therapy for musculoskeletal pain conditions. Current evidence, however, is limited to self-reported conditions and health services use. The purpose of this study was to use a large electronic health record database to determine whether a race disparity existed in use of physical therapy within 90 days of a new musculoskeletal diagnosis.

METHODS

Eligible patients (n = 52,384) were sampled from an Optum deidentified electronic health record database of 5 million adults distributed throughout the United States. In this database, patients were designated as "Black" and "White." Patients were eligible if they had a new diagnosis for musculoskeletal neck, shoulder, back, or knee pain between January 1, 2012, and December 31, 2017. Logistic regression and Cox proportional hazard models were computed before and after adjusting for covariates to estimate the association between race and receipt of physical therapy services within 90 days of musculoskeletal pain diagnoses.

RESULTS

Patients were on average 47.5 (SD = 14.9) years of age, 12.8% were Black, 87.2% were White, and 52.7% were female. Ten percent of Black patients and 15.5% of White patients received physical therapy services within 90 days of musculoskeletal pain diagnoses. After adjusting for covariates, White patients were 57% more likely (odds ratio = 1.57; 95% CI = 1.44-1.71) to receive physical therapy compared with Black patients and had significantly shorter time to physical therapy than Black patients (hazard ratio = 1.53; 95% CI = 1.42-1.66).

CONCLUSIONS

In a nationally distributed cohort, Black patients were less likely than White patients to utilize physical therapy and had a longer time to utilization of physical therapy for musculoskeletal pain.

IMPACT

These findings highlight the need to determine the mechanisms underlying the observed disparities and how these disparities influence health outcomes.

"I wish it had a place to go": a nominal group study of barriers to the effectiveness of non-surgical treatments for knee osteoarthritis inclusive of minority populations

Objective

To examine patient experience, views, and opinions regarding the ineffectiveness of the current knee osteoarthritis (OA) treatments.

Methods

Nominal groups were conducted with consecutive clinic patients with knee OA, oversampling African Americans. Patients discussed and rank-ordered their concerns.

Results

Fourteen nominal groups with 48 knee OA patients were conducted with a mean age of 60.6 years (standard deviation, 9.8) and a knee OA duration of 7.8 years (sd, 5.4); 25% were men, and 54% were African American. The most frequently cited highly ranked concerns for the ineffectiveness of current knee OA treatments were as follows: (1) medication-related—(A) side effects (3 groups; 4% vote), (B) limited efficacy (5 groups; 11% vote), (C) medication not targeting underlying disease (7 groups; 16% vote), (D) lack of personalized medication use (3 groups; 4% vote), (E) temporary benefit (3 groups; 6% vote), and (F) fear of addiction/natural treatment preference (2 groups; 3% vote); (2) exercise/physical therapy-related—(G) exacerbation of joint pain (1 group; 3% vote), (H) difficulty in doing exercises (2 groups; 2% vote), (I) lack of motivation (8 groups; 12% vote), (J) technical challenges/lack of personalized exercise regimens (1 group; 1% vote), and (K) cost (2 groups; 3% vote); and (3) weight loss-related—(L) difficulty in achieving weight loss (4 groups; 6% vote) and (M) motivation (1 group; 1% vote).

Conclusions

A representative sample of participants with knee OA identified several barriers to the effectiveness of current knee OA treatments. This new knowledge provides insights for making the current treatment options potentially more usable and/or more effective.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02676-8.

Trends and disparities in osteoarthritis prevalence among US adults, 2005-2018

Studies reporting trends and disparities of osteoarthritis (OA) in the United States are limited. We aimed to examine trends and disparities of OA prevalence among US adults, from 2005 to 2018. Continuous National Health and Nutrition Examination Survey (NHANES) data from 2005–2006 to 2017–2018 were analyzed. Age-adjusted and self-reported OA prevalence, stratified by race/ethnicity and socioeconomic status (SES), was calculated separately for men and women. The linear trend and the association between the survey cycles and OA prevalence were assessed. Age-adjusted and self-reported OA prevalence linearly increased in the seven survey cycles (both P_{linear trend} ≤ 0.0002) in men and women. Non-Hispanic Caucasians (both P_{linear trend} ≤ 0.0001) in both genders and Non-Hispanic African Americans women (P_{linear trend} ≤ 0.0001) had significantly increasing linear trends in OA prevalence. In addition, people with lower SES had a lower age-adjusted prevalence of self-reported OA when compared to those with higher SES. The increasing linear trends still existed among both men and women after adjusting for multiple confounders (both P_{linear trend} ≤ 0.002). There were significant rising trends and disparities in self-reported OA prevalence among US men and women between 2005 and 2018.

Use of Complementary and Alternative Therapy for Knee Osteoarthritis: Race and Gender Variations

Objective

To evaluate race and gender variations in complementary and alternative medicine (CAM) use for knee osteoarthritis (OA) (unadjusted and adjusted for demographic and clinical factors).

Methods

A secondary analysis of cross‐sectional data was conducted. The sample included Veterans Affairs patients 50 years of age or older with symptomatic knee OA. Current use of various CAM therapies was assessed at baseline. Logistic regression models were used to compare race and gender differences in the use of specific CAMs.

Results

The sample included 517 participants (52.2% identified as African American [AA]; 27.1% identified as female). After adjusting for demographic and clinical factors, AA participants, compared with white participants, were less likely to use joint supplements (odds ratio [OR]: 0.53; 95% confidence interval [CI], 0.31‐0.90]); yoga, tai chi, or pilates (OR: 0.39; 95% CI: 0.19‐0.77); and chiropractic care (OR: 0.51; 95% CI: 0.26‐1.00). However, they were more likely to participate in spiritual activities (OR: 2.02; 95% CI: 1.39‐2.94). Women, compared with men, were more likely to use herbs (OR: 2.42; 95% CI: 1.41‐4.14); yoga, tai chi, or pilates (OR: 2.09; 95% CI: 1.04‐4.19); acupuncture, acupressure, or massage (OR: 2.45; 95% CI: 1.28‐4.67); and spiritual activities (OR: 1.68; 95% CI: 1.09‐2.60). The interactive effects of race and gender were significant in the use of herbs (P = 0.008); yoga, tai chi, or pilates (P = 0.011); acupuncture, acupressure or massage (P = 0.038); and spiritual activities (P < 0.001).

Conclusion

There are race and gender differences in the use of various CAMs for OA. As benefits and limitations of CAM therapies vary, clinicians must be aware of these differences.

Ultrasonographic assessment of femoral cartilage thickness in patients with Helicobacter pylori infection

OBJECTIVES

Helicobacter pylori is a major cause of gastritis and a potential trigger of inflammatory disease. The effect of H pylori infection on distal femoral cartilage has yet to be evaluated. The aim of this study was to evaluate femoral cartilage thickness in patients with H pylori infection and to find whether this infection affects femoral cartilage thickness.

METHODS

This cross-sectional study included 199 patients. To measure the thickness of femoral articular cartilage, 99 patients with H pylori infections and 100 with H pylori-negative controls were enrolled into two groups. The measurements were made using linear probe ultrasonography with the patients in supine positions and their knees in maximum flexion. Demographic, clinical, endoscopic and laboratory data were collected for all patients.

RESULTS

Both the right and left femoral condyles had thinner cartilage thickness in the H pylori-positive group than in the H pylori-negative group (P = .016, P = .036). For the intercondylar area and lateral femoral condyles, although the H pylori-positive patients had thinner femoral cartilage thickness than the H pylori-negative individuals for both extremities, this finding was not statistically significant (P > .05).

CONCLUSION

Femoral cartilage was thinner in patients with H pylori than patients without H pylori for right and left medial femoral condyles. This study suggests that H pylori infections may affect femoral cartilage thickness and potentially increase the risk of cartilage degeneration.

Quantifying Mediators of Racial Disparities in Knee Osteoarthritis Outcome Scores: A Cross-Sectional Analysis

Studies on symptomatic osteoarthritis suggest that Black patients report worse pain and symptoms compared with White patients with osteoarthritis. In this study, we aimed to quantify the relationship among variables such as overall health and socioeconomic status that may contribute to disparities in patient-reported outcomes.

Racial/Ethnic, Socioeconomic, and Geographic Disparities in the Epidemiology of Knee and Hip Osteoarthritis

It is estimated that 32.5 million US adults have clinical osteoarthritis (OA), with the most common sites being knee and hip. OA is associated with substantial individual and societal costs. Race/ethnicity, socioeconomic status (SES), and geographic variations in the prevalence of knee and hip OA are well established around the world. In addition, clinical outcomes associated with hip and knee OA differ according to race/ethnicity, SES, and geography. This variation is likely multifactorial and may also reflect country-specific differences in health care systems. The interplay between different factors, such as geography, SES, and race/ethnicity, is difficult to study.

Racial Differences in Performance-Based Function and Potential Explanatory Factors Among Individuals With Knee Osteoarthritis

OBJECTIVE

In individuals with knee osteoarthritis (OA), self-reported physical function is poorer in African Americans than in whites, but whether this difference holds true for objective assessments is unclear. The purpose of this study was to examine racial differences in performance-based physical function as well as potential underlying factors contributing to these racial differences.

METHODS

Participants with knee OA from a randomized controlled trial completed the 2-minute step test (2MST), timed-up-and-go (TUG), and 30-second chair stand (30s-CST) at baseline. Race differences in performance-based function were assessed by logistic regression. Separate models were adjusted for sets of demographic, socioeconomic, psychological health, and physical health variables.

RESULTS

In individuals with knee OA (n = 322; 72% women, 22% African American, mean ± SD age 66 ± 11 years, mean ± SD body mass index 31 ± 8 kg/m2 ), African Americans (versus whites) had greater unadjusted odds of poorer function (30s-CST odds ratio [OR] 2.79 [95% confidence interval (95% CI) 1.65-4.72], 2MST OR 2.37 [95% CI 1.40-4.03], and TUG OR 3.71 [95% CI 2.16-6.36]). Relationships were maintained when adjusted for demographic and psychological health covariates, but they were either partially attenuated or nonsignificant when adjusted for physical health and socioeconomic covariates.

CONCLUSION

African American adults with knee OA had poorer unadjusted performance-based function than whites. Physical health and socioeconomic characteristics diminished these differences, emphasizing the fact that these factors may be important to consider in mitigating racial disparities in function.

"Bearing the Pain": The Experience of Aging African Americans With Osteoarthritis Pain

Studies document that osteoarthritis-related joint pain is more severe in African American older adults, but research on the personal experience of osteoarthritis pain self-management in this population is limited. Using a qualitative descriptive design, our objective was to extend our understanding of the experience of life with osteoarthritis pain. Eighteen African Americans (50 years and older) were recruited from Louisiana to participate in a single semi-structured, in-depth interview. A conventional content analysis revealed that “Bearing the pain” characterized how older African Americans dealt with osteoarthritis. Bearing the pain comprised three actions: adjusting to pain, sharing pain with others, and trusting God as healer. We discovered that a metapersonal experience subsumes the complex biopsychosocial-cultural patterns and the intricate interaction of self, others, and God in living with and managing osteoarthritis pain. Study findings have implications for application of more inclusive self-management frameworks and interventions.

Demographic Tendencies and Hospitalization Outcomes Among Inpatient Admissions of Osteoarthritis in the Midwest: A 2016 State Inpatient Database Study

Objective

To assess the inpatient prevalence of osteoarthritis in a Midwestern state and to identify trends in demographics and hospital outcomes.

Methods

The Wisconsin State Inpatient Sample Database (2016) was queried to identify hospitalization records with a primary diagnosis of osteoarthritis. Bivariate correlation, descriptive statistics, and single-layer mean comparison were used for categorical and continuous data within the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) sub-groups.

Results

In 2016, there were 64,805 admissions of osteoarthritis. The most common (>0.09%) were the right knee osteoarthritis (24.5%), left knee osteoarthritis (23%), right hip osteoarthritis (16.9%), left hip osteoarthritis (14.3%), knee unspecified osteoarthritis (11.5%), bilateral knees osteoarthritis (7%), and right shoulder osteoarthritis (2%). The mean age on admission was 67 years for each hip osteoarthritis, 66 years for each knee osteoarthritis, and 69 years for right shoulder osteoarthritis. The mean length of stay was 3.15 days for bilateral knee osteoarthritis and 1.92 days for the right shoulder osteoarthritis. Total inpatient charges and in-hospital mortality were highest in right shoulder osteoarthritis (USD 52,699.40 [0.6%]; N = 6), and total charges were lowest in right and left hip osteoarthritis (44,689.54 and 44,427.33, respectively). A greater frequency of females and Caucasians was consistently admitted within each of the included ICD-10-CM OA sub-groupings. Age was correlated with charge in the left hip osteoarthritis (r = 0.050) and right shoulder osteoarthritis (r = 0.068), and was negatively correlated with charge in the bilateral knee osteoarthritis (r = -0.115), right knee osteoarthritis (r = -0.054), and left knee osteoarthritis (r = -0.060).

Conclusions

In Wisconsin, with somewhat of a generalizability to other Midwestern states, attention should be given to Caucasian, elderly, and female patients with osteoarthritis of the hip and knee. Further studies are needed to broaden the understanding of cost utilization, how charges and hospital stay compare nationwide, and where preventative efforts are needed.

Shoulder Arthroplasty Utilization Based on Race - Are Black Patients Underrepresented?

BACKGROUND

This study aimed to analyze national and institutional trends in shoulder arthroplasty utilization based on patient race.

METHODS

The Nationwide Inpatient Sample (NIS) was employed to determine racial trends in shoulder arthroplasty utilization at a national level. An institutional database was then utilized to retrospectively identify all patients, undergoing shoulder arthroplasty within 2011-2013. Descriptive statistics were used to compare self-identified black and non-black subpopulations.

RESULTS

The NIS identified 256,832 primary shoulder arthroplasties within 2005-2011. Black patients constituted 3.92% (n=10,074) of cases. Utilization increased from 3.36% in 2005 to 4.49% in 2011. Locally, a total number of 1,174 primary shoulder arthroplasties were performed, the recipients of 5.96% (n=70) of which were black. Females accounted for 48/70 (68.6%) of black patients. Black patients had a higher body mass index (33.6 vs. 30.1, P<0.0001) and were younger (62.6 vs. 67.2 years, P<0.0001), compared to the non-black patients. Regarding insurance type, 1,074 patients (i.e., 65 black and 1,009 non-black) had comprehensive insurance data. Chi-square analysis of five major insurance categories, including private, Medicare, Medicaid, workers' compensation, and personal injury, indicated no difference in insurance patterns (χ²=3.658, P=0.454).

CONCLUSION

The findings revealed significant racial disparity in shoulder arthroplasty utilization both at national and institutional levels. This disparity exists despite the similar rates of osteoarthritis in both white and black patients. Black patients in our institution had similar clinical, demographic, and socioeconomic characteristics as in our non-black patients. The obtained results highlighted the need for the expansion of black patients' access to care services related to major joint reconstruction.

Movement-evoked pain, physical function, and perceived stress: An observational study of ethnic/racial differences in aging non-Hispanic Blacks and non-Hispanic Whites with knee osteoarthritis

BACKGROUND

Knee osteoarthritis (OA) is a pervasive musculoskeletal condition, often exacerbated by movement-evoked pain (MEP). Despite established research demonstrating significant racial differences in OA pain, few studies have investigated ethnic/racial group differences in MEP and lower extremity function and their association with psychosocial factors, such as perceived stress. Therefore, the primary aims were: (1) to identify ethnic/racial group differences in persons with or at risk for knee OA pain based on MEP, physical performance, and perceived stress measures, and (2) to determine if perceived stress explains the relationship between MEP and function in non-Hispanic Blacks (NHBs) and non-Hispanic Whites (NHWs).

METHODS

A total of 162 NHB and NHW community-dwelling older adults (50-78 years of age) were included in this analysis from the Understanding Pain and Limitations in Osteoarthritic Disease (UPLOAD) cross-sectional cohort study. Demographic, anthropometric, pain and functional parameters were assessed using a battery of validated instruments. Descriptive statistics, parametric, and multivariate analyses were conducted to determine ethnic/racial differences in perceived stress, MEP, and function.

RESULTS

Our results support the hypothesis that among persons with knee OA pain, NHBs have significantly greater MEP and lower functional level, despite similar levels of perceived stress. However, perceived stress was more strongly related to MEP in NHB compared to NHWs. Differences in function were limited to walking speed, where NHWs demonstrated faster gait speed.

CONCLUSIONS

Our cross-sectional study demonstrated important ethnic/racial differences in MEP and function. Also, perceived stress had a stronger effect on MEP in NHBs, suggesting that perceived stress may more strongly influence pain with physical movement among NHB adults. MEP may be a clinically important pain outcome to measure in persons with OA, and these data warrant future research on the impact of stress on pain and functional outcomes in older adults, particularly in NHBs.

Risk factor heterogeneity for medial and lateral compartment knee osteoarthritis: analysis of two prospective cohorts

OBJECTIVE

To evaluate the etiologic heterogeneity between medial and lateral tibiofemoral radiographic osteoarthritis (ROA).

METHODS

Knees without medial or lateral tibiofemoral ROA at baseline were followed for 60-month in Multicenter Osteoarthritis Study (MOST) and for 48-month in Osteoarthritis Initiative (OAI). We examined the relation of previously reported risk factors to incident medial and lateral tibiofemoral ROA separately and determined the etiology heterogeneity with a ratio of rate ratios (RRs) (i.e., the RR for medial tibiofemoral ROA divided by the RR for lateral tibiofemoral ROA) using a duplication method for Cox proportional hazard regression.

RESULTS

Of 2,016 participants in MOST, 436 and 162 knees developed medial or lateral tibiofemoral ROA, respectively. Obesity and varus malalignment were 95% and 466% more strongly associated with incident medial tibiofemoral ROA than with lateral tibiofemoral ROA, respectively (ratios of RRs, 1.95 [95% confidence interval (CI):1.05-3.62] and 5.66 [95% CI:3.20-10.0]). In contrast, the associations of female sex and valgus malalignment with incident medial tibiofemoral ROA were weaker or in an opposite direction compared with lateral tibiofemoral Osteoarthritis (OA) (ratios of RRs, 0.40 [95% CI:0.26-0.63] and 0.20 [95% CI:0.12-0.34], respectively). Older age tended to show a weaker association with incident medial tibiofemoral ROA than with incident lateral tibiofemoral ROA. No heterogeneity was observed for the relation of race, knee injury, or contralateral knee ROA. These findings were closely replicated in OAI.

CONCLUSION

Risk factor profiles for medial and lateral tibiofemoral ROA are different. These results can provide a framework for the development of targeted prevention and potential treatment strategies for specific knee OA subtypes.

Quadriceps Weakness in Individuals with Coexisting Medial and Lateral Osteoarthritis

Background

This study examined whether individuals who have mild medial osteoarthritis (OA) of the knee with coexisting lateral OA have less muscle strength than individuals who do not have lateral OA.

Methods

A series of 153 individuals (84% of whom were women) between 48 and 88 years old who had Kellgren and Lawrence (KL) grade-2 OA in the medial compartment of the knee underwent radiographic evaluation to assess the presence of lateral OA, which was graded with the system of the Osteoarthritis Research Society International (OARSI) atlas as well as the KL system. The isometric maximum strengths of the quadriceps, the hip abductors, and the hip extensors were evaluated with use of a handheld dynamometer.

Results

Individuals who had coexisting medial and lateral OA had more severe knee pain and weaker quadriceps than those who did not have lateral OA. The study adjusted for age and sex both for the OARSI atlas system (adjusted difference in mean strength: 0.272 Nm/kg, 95% confidence interval [CI]: 0.143 to 0.401 Nm/kg) and for KL grading (adjusted difference in mean strength: 0.185 Nm/kg, 95% CI: 0.061 to 0.309 Nm/kg). Logistic regression analysis showed that weakness of the quadriceps increased the odds of the presence of lateral OA sevenfold after adjustments using the OARSI atlas were made for age, sex, anatomical axis, range of motion of the knee, and intensity of pain in the knee.

Conclusions

Individuals who had coexisting medial and lateral OA had weaker quadriceps than individuals who had mild medial OA alone. Paying close attention to quadriceps weakness might provide a key to clarifying the pathogenesis of bicompartmental disease in the tibiofemoral joint.

Level of Evidence

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Racial-Ethnic Differences in Osteoarthritis Pain and Disability: A Meta-Analysis

Osteoarthritis (OA), a leading cause of disability and pain, affects 32.5 million Americans, producing tremendous economic burden. Although some findings suggest that racial/ethnic minorities experience increased OA pain severity, other studies have shown conflicting results. This meta-analysis examined differences in clinical pain severity between African Americans (AAs) and non-Hispanic whites with OA. Articles were initially identified between October 1 and 5, 2016, and updated May 30, 2018, using PubMed, Web of Science, PsycINFO, and the Cochrane Library Database. Eligibility included English-language peer-reviewed articles comparing clinical pain severity in adult black/AA and non-Hispanic white/Caucasian patients with OA. Nonduplicate article abstracts (N = 1,194) were screened by 4 reviewers, 224 articles underwent full-text review, and 61 articles reported effect sizes of pain severity stratified by race. Forest plots of the standard mean difference showed higher pain severity in AAs for studies using the Western Ontario and McMasters Universities Osteoarthritis Index (0.57; 95% confidence interval [CI], 0.54-0.61) and non-Western Ontario and McMasters Universities Osteoarthritis Index studies (0.35, 95% CI, 0.23-0.47). AAs also showed higher self-reported disability (0.38, 95% CI, 0.22-0.54) and poorer performance testing (-0.58, 95% CI, -0.72 to -0.44). Clinical pain severity and disability in OA is higher among AAs and future studies should explore the reasons for these differences to improve pain management. PERSPECTIVE: This meta-analysis shows that differences exist in clinical pain severity, functional limitations, and poor performance between AAs and non-Hispanic whites with OA. This research may lead to a better understanding of racial/ethnic differences in OA-related pain.

Update on the epidemiology, risk factors and disease outcomes of osteoarthritis

Osteoarthritis (OA) is the most frequent form of arthritis and a leading cause of pain and disability worldwide. OA can affect any synovial joint, although the hip, knee, hand, foot and spine are the most commonly affected sites. Knowledge about the occurrence and risk factors for OA is important to define the clinical and public health burden of the disease to understand mechanisms of disease occurrence and may also help to inform the development of population-wide prevention strategies. In this article, we review the occurrence and risk factors for OA and also consider patient-reported outcome measures that have been used for the assessment of the disease.

Associations between the chemokine biomarker CCL2 and knee osteoarthritis outcomes: the Johnston County Osteoarthritis Project

OBJECTIVE

Our study analyzes the association between chemokine-ligand-2 (CCL2) serum concentrations at baseline and knee radiographic osteoarthritis (OA) (knee-rOA), knee-rOA progression, individual radiographic features and knee symptomatic OA at 5-year follow-up.

DESIGN

OA outcomes were analyzed in a community-based cohort including a baseline enrollment and a 5-year follow-up. Baseline CCL2 serum concentrations were assessed by multiplex assay and associated with presence or progression of individual radiographic features at 5-year follow-up. Separate multiple logistic regression models were used to examine adjusted associations between baseline CCL2 and each of the knee OA variables at follow-up. CCL2 at baseline was modeled as an explanatory variable, whereas each of the knee OA variables at follow-up served as the response variables. Models were adjusted for age, BMI, race, and sex. Trend tests were conducted to assess any linear effect on outcomes across CCL2 tertiles.

RESULTS

Participants (n = 168) had a median age of 57-years and median BMI of 29 kg/m2. About 63% of all participants were women, and 58% Caucasian (42% African American). In adjusted logistic models, continuous log-CCL2 was significantly associated with knee-rOA. For each unit increase in log CCL2, the odds of having knee-rOA at follow-up was increased by 72%. CCL2 tertiles showed significant linear associations with presence and progression of knee-rOA and medial joint space narrowing (JSN), but not with presence or progression of osteophytes, bone sclerosis, knee symptoms, or symptomatic knee-rOA.

CONCLUSIONS

Serum CCL2 may help to elucidate some mechanisms of joint destruction and identify individuals with higher odds of structural knee changes.

Natural history of pain and disability among African-Americans and Whites with or at risk for knee osteoarthritis: A longitudinal study

OBJECTIVE

Compare knee pain and disability between African Americans (AAs) and Whites (WHs), with or at risk of knee osteoarthritis (KOA), over 9 years, and evaluate racial disparities in KOA-related symptoms across socioeconomic and clinical characteristics.

DESIGN

Osteoarthritis Initiative (OAI) participants were evaluated annually over 9 years for pain and disability, assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and a numerical rating scale (NRS) for knee pain severity. Mean annual WOMAC pain, NRS pain, and WOMAC disability levels were estimated by race using mixed effects models, adjusted for age, sex, education, marital status, body mass index (BMI), depression, and baseline Kellgren-Lawrence grade score. Race-specific mean WOMAC pain scores were also estimated in analyses stratified by socioeconomic and clinical characteristics.

RESULTS

AAs reported worse mean WOMAC pain compared to WHs at baseline (3.69 vs 2.20; P ≤ 0.0001) and over 9 years of follow-up, with similar disparities reflected in NRS pain severity and WOMAC disability. Radiographic severity did not account for the differences in pain and disability, as substantial and significant racial disparities were observed after stratification by Kellgren-Lawrence grade. Depression and low income exacerbated differences in WOMAC pain between AAs and WHs by a substantial and significant magnitude.

CONCLUSIONS

Over 9 years of follow-up, AAs reported persistently greater KOA symptoms than WHs. Socioeconomically and clinically disadvantaged AAs reported the most pronounced disparities in pain and disability.

Race, sex, and risk factors in radiographic worsening of knee osteoarthritis

OBJECTIVES

Characterize radiographic worsening in knee osteoarthritis (KOA) by race and sex over 4 years and evaluate the role of established risk factors in observed race/sex differences.

METHODS

Whites (WHs) (694 males and 929 females) and African-Americans (AAs) (92 males and 167 females) at risk for radiographic KOA were eligible. Cox shared frailty models were used to estimate race and sex group differences in radiographic worsening, defined by Kellgren-Lawrence (K-L) and OARSI joint space narrowing (JSN). Mixed effect models for repeated measures were used to estimate race- and sex-specific mean medial and lateral fixed joint space width (fJSW) over 4 years of follow-up, as well as annual loss of fJSW.

RESULTS

Risk of OARSI medial JSN grade worsening was higher among AA males than WH females [HR = 2.28, (95% CI: 1.14-4.57)], though adjustment for KOA risk factors attenuated the association. Compared to WH females, WH males had lower risk of K-L grade worsening [adjusted HR = 0.75 (95% CI: 0.58-0.96)]. Mean baseline medial fJSW (mm) was 6.49 in WH and AA males, 5.42 in WH females, and 5.41 in AA females. Annual change in mean medial fJSW was greater in AA males (-0.19mm/year) than in other subgroups (-0.09 WH males, -0.07 WH females, -0.10 AA females, p < 0.0001). Compared to WHs, AAs had less lateral fJSW at baseline and throughout follow-up.

CONCLUSIONS

Compared to WHs and AA females, AA males experienced higher risk of medial joint space loss. Controlling for established risk factors attenuated associations between race/sex and disease worsening, suggesting that risk factors such as obesity, history of knee injury, and bony finger joint enlargements largely explain race/sex variations in rates of KOA development and progression.

Relationship between Kellgren-Lawrence score and 3D kinematic gait analysis of patients with medial knee osteoarthritis using a new gait system

Knee osteoarthritis (KOA) is reported to have characteristic kinematics during walking. However, the relationship between Kellgren-Lawrence (K/L) score and the 3D kinematic gait of patients with medial KOA remains unclear. Here, ninety-seven patients with medial KOA and thirty-eight asymptomatic participants were involved. Patients with medial KOA were divided into early, moderate, and severe KOA based on the K/L score. Through kinematic gait analysis, we found a relationship between K/L score and 3D kinematic gait for patients. All KOA knees had a significantly reduced range of motion. As the K/L score was increasing, the knee flexion at the heel strike and 50% of the stance phase increased while the peak knee flexion in the swing phase decreased. In addition, the adduction and femoral rotation increased internally at the heel strike, 50% of the stance phase, and maximum angle of the swing phase. Femoral translation increased anteriorly and distally at the heel strike and 50% of the stance phase. The severe group had more medial translation than the asymptomatic groups. Significant alterations of three-dimensional joint kinematics were identified in subjects suffering various severities in Chinese patients. This study provides an important reference for the treatment options, therapy assessment, and rehabilitation of KOA.

The prevalence of radiographic and MRI-defined patellofemoral osteoarthritis and structural pathology: a systematic review and meta-analysis

BACKGROUND

Patellofemoral osteoarthritis (PF OA) is more prevalent than previously thought and contributes to patient's suffering from knee OA. Synthesis of prevalence data can provide estimates of the burden of PF OA.

OBJECTIVE

This study aims to conduct a systematic review and meta-analysis on the prevalence of PF OA and structural damage based on radiography and MRI studies in different populations.

METHODS

We searched six electronic databases and reference lists of relevant cross-sectional and observational studies reporting the prevalence of PF OA. Two independent reviewers appraised methodological quality. Where possible, data were pooled using the following categories: radiography and MRI studies.

RESULTS

Eighty-five studies that reported the prevalence of patellofemoral OA and structural damage were included in this systematic review. Meta-analysis revealed a high prevalence of radiographic PF OA in knee pain or symptomatic knee OA (43%), radiographic knee OA or at risk of developing OA (48%) and radiographic and symptomatic knee OA (57%) cohorts. The MRI-defined structural PF damage in knee pain or symptomatic population was 32% and 52% based on bone marrow lesion and cartilage defect, respectively.

CONCLUSION

One half of people with knee pain or radiographic OA have patellofemoral involvement. Prevalence of MRI findings was high in symptomatic and asymptomatic population. These pooled data and the variability found can provide evidence for future research addressing risk factors and treatments for PF OA.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42016035649).

Bacterial Contribution in Chronicity of Wounds

A wound is damage of a tissue usually caused by laceration of a membrane, generally the skin. Wound healing is accomplished in three stages in healthy individuals, including inflammatory, proliferative, and remodeling stages. Healing of wounds normally starts from the inflammatory phase and ends up in the remodeling phase, but chronic wounds remain in an inflammatory stage and do not show progression due to some specific reasons. Chronic wounds are classified in different categories, such as diabetic foot ulcer (DFU), venous leg ulcers (VLU) and pressure ulcer (PU), surgical site infection (SSI), abscess, or trauma ulcers. Globally, the incidence rate of DFU is 1-4 % and prevalence rate is 5.3-10.5 %. However, colonization of pathogenic bacteria at the wound site is associated with wound chronicity. Most chronic wounds contain more than one bacterial species and produce a synergetic effect that results in previously non-virulent bacterial species becoming virulent and causing damage to the host. While investigating bacterial diversity in chronic wounds, Staphylococcus, Pseudomonas, Peptoniphilus, Enterobacter, Stenotrophomonas, Finegoldia, and Serratia were found most frequently in chronic wounds. Recently, it has been observed that bacteria in chronic wounds develop biofilms that contribute to a delay in healing. In a mature biofilm, bacteria grow slowly due to deficiency of nutrients that results in the resistance of bacteria to antibiotics. The present review reflects the reasons why acute wounds become chronic. Interesting findings include the bacterial load, which forms biofilms and shows high-level resistance toward antibiotics, which is a threat to human health in general and particularly to some patients who have acute wounds.

Mechanical and neuromuscular changes with lateral trunk lean gait modifications

Lateral trunk lean (LTL) is a proposed intervention for knee osteoarthritis but increased muscular demands have not been considered. The objective was to compare lower extremity and trunk muscle activation and joint mechanics between normal and increased LTL gait in healthy adults. Participants (n=20, mean age 22 years) were examined under two gait conditions: normal and increased LTL. A motion capture system and force plates sampled at 100 and 2000Hz respectively were used to determine joint angles and external moments including LTL angle and external knee adduction moment (KAM). Surface electromyography, sampled at 2000Hz, measured activation of six trunk/hip muscles bilaterally. Peak LTL angle, peak KAM, gait speed, and mean values from electromyography waveforms were compared between normal and LTL conditions using paired t-tests or 2-way analysis of variance. There was a significant (p<0.05) increase in peak LTL angle, decrease in first but not second peak KAM, and decrease in gait speed during LTL gait. There were significant (p<0.01) increases in external oblique and iliocostalis muscle activation during LTL gait. There was no change in activation for internal oblique, rectus abdominis, longissimus, and gluteus medius. LTL gait decreased early/mid-stance KAM demonstrating its ability to decrease medial compartment knee loading. Increases in external oblique and iliocostalis activation were present but small to moderate in size and unlikely to lead to short term injury. Longitudinal studies should evaluate the effectiveness of increased LTL for knee osteoarthritis and if the increase in muscular demands leads to negative long term side effects.

Longitudinal analysis of cartilage T2 relaxation times and joint degeneration in African American and Caucasian American women over an observation period of 6 years - data from the Osteoarthritis Initiative

OBJECTIVES

To investigate the change in cartilage T2 values and structural degeneration in knee joints over 72 months in women of African American (AA) vs Caucasian American (CA) ethnicity.

METHODS

Knee 3T magnetic resonance imaging (MRIs) from baseline, 24, 48 and 72 months visits of 100 AA and 100 CA women from the Osteoarthritis Initiative (OAI) were assessed for cartilage T2 values and whole-organ magnetic resonance imaging (WORMS) score. Subjects were pair-matched by age, body mass index (BMI), Kellgren-Lawrence (KL) score, clinical site and subcohort within the OAI. We compared the rate of change in whole knee cartilage T2 values and WORMS cartilage, bone marrow edema pattern (BMEP) and meniscus scores between the two ethnic groups using mixed random effects models.

RESULTS

At 24 and 48 months 60 subjects and at 72 months 45 subjects per group were available for analysis resulting in 38 complete pairs with data of all time points. Compared to CA, cartilage T2 values in AA increased at a significantly faster rate at baseline (AA: 0.45 ms/y, CA: 0.35 ms/y, P = 0.029) and averaged over 6 years (AA: 0.36 ms/y, CA: 0.27 ms/y, P = 0.039) with changes in both groups reaching a plateau by 48 months. Cartilage, meniscus and BMEP scores tended to increase in both groups during follow up, but rates of change did not differ by ethnicity.

CONCLUSION

Cartilage T2 values increased faster over 72 months in AA than CA, however changes in WORMS cartilage, meniscus and BMEP scores did not differ. T2 values may be able to distinguish ethnicity-related differences of cartilage degeneration at an early stage before differences in structural joint degeneration appear.

Annual Incidence of Knee Symptoms and Four Knee Osteoarthritis Outcomes in the Johnston County Osteoarthritis Project

OBJECTIVE

To estimate annual incidence rates (IRs) of knee symptoms and 4 knee osteoarthritis (OA) outcomes (radiographic, symptomatic, severe radiographic, and severe symptomatic), overall and stratified by sociodemographic characteristics and knee OA risk factors.

METHODS

We analyzed baseline (1991-1997) and first followup (1999-2003) data (n = 1,518) from the Johnston County Osteoarthritis Project. Participants were African American and white adults, ages ≥45 years, living in Johnston County, North Carolina, US. Knee symptoms were pain, aching, or stiffness on most days in a knee. Radiographic OA was Kellgren/Lawrence grade ≤2 (severe radiographic ≥3) in at least 1 knee. Symptomatic OA was defined as symptoms in a radiographically affected knee; severe symptomatic OA was defined as severe symptoms and severe radiographic OA.

RESULTS

The median followup time was 5.5 years. Average annual IRs were 6% for symptoms, 3% for radiographic OA, 2% for symptomatic OA, 2% for severe radiographic OA, and 0.8% for severe symptomatic OA. Across outcomes, IRs were highest among those with the following baseline characteristics: age ≥75 years, obese, a history of knee injury, or an annual household income ≤$15,000.

CONCLUSION

The annual onset of knee symptoms and 4 OA outcomes in Johnston County was high. This may preview the future of knee OA in the US and underscores the urgency of clinical and public health collaborations that reduce risk factors for, and manage the impact of, these outcomes. Inexpensive, convenient, and proven strategies (e.g., physical activity, self-management education courses) complement clinical care and can reduce pain and improve quality of life for people with arthritis.

Multivariate Radiological-Based Models for the Prediction of Future Knee Pain: Data from the OAI

In this work, the potential of X-ray based multivariate prognostic models to predict the onset of chronic knee pain is presented. Using X-rays quantitative image assessments of joint-space-width (JSW) and paired semiquantitative central X-ray scores from the Osteoarthritis Initiative (OAI), a case-control study is presented. The pain assessments of the right knee at the baseline and the 60-month visits were used to screen for case/control subjects. Scores were analyzed at the time of pain incidence (T-0), the year prior incidence (T-1), and two years before pain incidence (T-2). Multivariate models were created by a cross validated elastic-net regularized generalized linear models feature selection tool. Univariate differences between cases and controls were reported by AUC, C-statistics, and ODDs ratios. Univariate analysis indicated that the medial osteophytes were significantly more prevalent in cases than controls: C-stat 0.62, 0.62, and 0.61, at T-0, T-1, and T-2, respectively. The multivariate JSW models significantly predicted pain: AUC = 0.695, 0.623, and 0.620, at T-0, T-1, and T-2, respectively. Semiquantitative multivariate models predicted paint with C-stat = 0.671, 0.648, and 0.645 at T-0, T-1, and T-2, respectively. Multivariate models derived from plain X-ray radiography assessments may be used to predict subjects that are at risk of developing knee pain.

Radiographic assessment of leg alignment and grading of knee osteoarthritis: A critical review

Knee osteoarthritis (OA) is a progressive joint disease hallmarked by cartilage and bone breakdown and associated with changes to all of the tissues in the joint, ultimately causing pain, stiffness, deformity and disability in many people. Radiographs are commonly used for the clinical assessment of knee OA incidence and progression, and to assess for risk factors. One risk factor for the incidence and progression of knee OA is malalignment of the lower extremities (LE). The hip-knee-ankle (HKA) angle, assessed from a full-length LE radiograph, is ideally used to assess LE alignment. Careful attention to LE positioning is necessary to obtain the most accurate measurement of the HKA angle. Since full-length LE radiographs are not always available, the femoral shaft - tibial shaft (FS-TS) angle may be calculated from a knee radiograph instead. However, the FS-TS angle is more variable than the HKA angle and it should be used with caution. Knee radiographs are used to assess the severity of knee OA and its progression. There are three types of ordinal grading scales for knee OA: global, composite and individual feature scales. Each grade on a global scale describes one or more features of knee OA. The entire description must be met for a specific grade to be assigned. The Kellgren-Lawrence scale is the most commonly-used global scale. Composite scales grade several features of knee OA individually and sum the grades to create a total score. One example is the compartmental grading scale for knee OA. Composite scales can respond to change in a variety of presentations of knee OA. Individual feature scales assess one or more OA features individually and do not calculate a total score. They are most often used to monitor change in one OA feature, commonly joint space narrowing. The most commonly-used individual feature scale is the OA Research Society International atlas. Each type of scale has its advantages; however, composite scales may offer greater content validity. Responsiveness to change is unknown for most scales and deserves further evaluation.

Racial disparities in total ankle arthroplasty utilization and outcomes

INTRODUCTION

The objective of this study was to examine the racial disparities in total ankle arthroplasty (TAA) utilization and outcomes.

METHODS

We used the National Inpatient Sample (NIS) to study the time-trends. Race was categorized as White and Black. Utilization rates were calculated for the U.S. general population per 100,000. Hospital length of stay, discharge disposition and mortality after TAA were assessed. We used the Cochran Armitage trend test to assess time-trends from 1998 to 2011 and chi-square test to compare TAA utilization. We used analysis of variance or chi-squared test to compare the characteristics of Whites and Blacks undergoing TAA and logistic regression to compare mortality, length of stay and discharge to home versus medical facility.

RESULTS

The mean ages for Whites undergoing TAA were 62 years and for Blacks was 52 years. Significant racial disparities were noted in TAA utilization rates (/100,000) in 1998, 0.14 in Whites vs. 0.07 in Blacks (P<0.0001; 2-fold) and in 2011, 1.17 in Whites vs. 0.33 in Blacks (P<0.0001; 4-fold). Racial disparities in TAA utilization increased significantly from 1998 to 2011 (P<0.0001). There was a trend towards statistical significance for the difference in the length of hospital stay in Blacks vs. Whites (52.9% vs. 44.3% with length of hospital stay higher than the median; P=0.08). Differences in the proportion discharged to an inpatient medical facility after TAA, 16.6% Blacks vs. 13.4% Whites, were not significant (P=0.36).

CONCLUSIONS

This study demonstrated significant racial disparities with lower TAA utilization and suboptimal outcomes in Blacks compared to Whites. Further studies are needed to understand the mediators of these disparities and to assess whether these mediators can be targeted to reduce racial disparities in TAA.

An Ongoing Assessment of Osteoarthritis in African Americans and Caucasians in North Carolina: The Johnston County Osteoarthritis Project

Osteoarthritis (OA) is the most common type of arthritis and is frequently associated with significant disability. Its public health impact is increasing due to the aging of the population and the obesity epidemic. The Johnston County Osteoarthritis Project is an ongoing, population-based prospective cohort begun in 1990 to fill knowledge gaps about prevalence, incidence, and progression of OA, and its risk factors, in African American and Caucasian men and women in North Carolina. Critically important phenotypic differences were observed in patterns of multi-joint OA burden, with African Americans much less likely than Caucasians to have hand OA and much more likely to have multiple large joint involvement. Racial differences also exist in systemic bone and joint tissue biomarkers. Novel potentially modifiable risk factors identified in this cohort include selenium and blood lead levels. Selected key findings of this ongoing study will be discussed.

Association of incident symptomatic hip osteoarthritis with differences in hip shape by active shape modeling: the Johnston County Osteoarthritis Project

OBJECTIVE

To investigate hip shape by active shape modeling (ASM) as a potential predictor of incident radiographic hip osteoarthritis (RHOA) and symptomatic hip osteoarthritis (SRHOA).

METHODS

All hips developing RHOA from baseline (Kellgren/Lawrence [K/L] grade 0/1) to mean 6-year followup (K/L grade ≥2, 190 hips) and 1:1 control hips (K/L grade 0/1 at both times, 192 hips) were included. Proximal femur shape was defined on baseline anteroposterior pelvis radiographs and submitted to ASM, producing a mean shape and continuous variables representing independent modes of shape variation. Mode scores (n = 14, explaining 95% of shape variance) were simultaneously included in logistic regression models with incident RHOA and SRHOA as dependent variables, adjusted for intraperson correlations, sex, race, body mass index (BMI), baseline K/L grade, and/or symptoms.

RESULTS

We evaluated 382 hips from 342 individuals: 61% women and 83% white, with mean age 62 years and mean BMI 29 kg/m(2) . Several modes differed by sex and race, but no modes were associated with incident RHOA overall. Among men only, modes 1 and 2 were significantly associated (for a 1-SD decrease in mode 1 score: odds ratio [OR] 1.7 [95% confidence interval (95% CI) 1.1-2.5] and for a 1-SD increase in mode 2 score: OR 1.5 [95% CI 1.0-2.2]) with incident RHOA. A 1-SD decrease in mode 2 or 3 score increased the odds of SRHOA by 50%.

CONCLUSION

This study confirms other reports that variations in proximal femur shape have a modest association with incident hip OA. The observation of proximal femur shape associations with hip symptoms requires further investigation.

Preoperative patient characteristics and outcomes of total knee arthroplasty in a multiethnic Asian population stratified by ethnicity

We aim to compare the patient profile and outcomes after TKA between the different racial groups in Singapore. Prospective data were collected from 364 patients who underwent TKA in Singapore General Hospital from January 2006 to May 2010. Patients were stratified according to ethnicity and we compared their preoperative demographic data, Short-Form 36 (SF-36), Oxford Knee (OKS) as well as Knee Society Scores (KSS). Malays were younger (62.0 ± 5.3) at time of surgery (p=0.05) and the body mass index of Chinese (27.9 ± 4.7) was lower than Malay (30.4 ± 5.0) and Indian (31.5 ± 4.5) patients (P<0.005). Malay (40.3 ± 11.0) and Indian (39.2 ± 9.3) patients had less favourable preoperative OKS than Chinese (35.9 ± 7.8) patients (P<0.05). All 3 ethnic groups achieved statistically significant improvements in outcome measures but did not differ significantly between the ethnicities.

Brief report: differences in multijoint symptomatic osteoarthritis phenotypes by race and sex: the Johnston County Osteoarthritis Project

OBJECTIVE

To determine differences in the phenotypes (patterns) of multiple-joint symptomatic osteoarthritis (OA) involvement by race and sex.

METHODS

A cross-sectional analysis of symptomatic OA phenotypes was performed in a community-based cohort, comprising subjects for whom data were collected from 4 sites of symptomatic OA involvement (the hands, knees, hips, and lumbosacral [LS] spine) at a single visit (2003-2010). Mutually exclusive phenotypes describing all combinations of these 4 sites were compared by race and by sex, using Fisher's exact tests. For those phenotypes occurring in >40 subjects, logistic regression was performed, with adjustments for race, sex, age, and body mass index (BMI), and interactions of race and sex were assessed.

RESULTS

The sample included 1,650 participants, of whom 36% were men and 32% were African American. The mean age of the subjects was 66 years, and the mean BMI was 31 kg/m(2). Overall, in this sample, 13% of subjects had symptomatic hand OA, 25% had symptomatic knee OA, 11% had symptomatic hip OA, and 28% had symptomatic LS spine OA. African Americans, as compared with Caucasians, were less likely to have involvement of symptomatic OA in the hand only, or in some combination of the hand and other sites, but were more likely to have involvement of the knee only. Men, as compared to women, were less likely to have involvement of the hand only, but were more likely to have involvement of the LS spine only.

CONCLUSION

There are differences in the phenotypes of multiple-joint symptomatic OA involvement by race and by sex that may influence the definitions of multiple-joint, or generalized, OA.

Periarticular osteophytes as an appendicular joint stress marker (JSM): analysis in a contemporary Japanese skeletal collection

Objective

The aim of this study was to investigate the possibility that periarticular osteophytes plays a role as a appendicular joint stress marker (JSM) which reflects the biomechanical stresses on individuals and populations.

Methods

A total of 366 contemporary Japanese skeletons (231 males, 135 females) were examined closely to evaluate the periarticular osteophytes of six major joints, the shoulder, elbow, wrist, hip, knee, and ankle and osteophyte scores (OS) were determined using an original grading system. These scores were aggregated and analyzed statistically from some viewpoints.

Results

All of the OS for the respective joints were correlated logarithmically with the age-at-death of the individuals. For 70 individuals, in whom both sides of all six joints were evaluated without missing values, the age-standardized OS were calculated. A right side dominancy was recognized in the joints of the upper extremities, shoulder and wrist joints, and the bilateral correlations were large in the three joints on the lower extremity. For the shoulder joint and the hip joint, it was inferred by some distinctions that systemic factors were relatively large. All of these six joints could be assorted by the extent of systemic and local factors on osteophytes formation. Moreover, when the age-standardized OS of all the joints was summed up, some individuals had significantly high total scores, and others had significantly low total scores; namely, all of the individuals varied greatly in their systemic predisposition for osteophytes formation.

Conclusions

This study demonstrated the significance of periarticular osteophytes; the evaluating system for OS could be used to detect differences among joints and individuals. Periarticular osteophytes could be applied as an appendicular joint stress marker (JSM); by applying OS evaluating system for skeletal populations, intra-skeletal and inter-skeletal variations in biomechanical stresses throughout the lives could be clarified.

Epidemiology of osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis in the United States and is a leading cause of disability. It is typically defined in epidemiologic studies by radiographic findings and consideration of symptoms. Its incidence and prevalence are rising, likely related to the aging of the population and increasing obesity. Risk factors for OA include numerous person-level factors, such as age, sex, obesity, and genetics, as well as joint-specific factors that are likely reflective of abnormal loading of the joints. In studying OA, several methodologic challenges exist that can hamper our ability to identify pertinent relationships.

Lumbar spine radiographic features and demographic, clinical, and radiographic knee, hip, and hand osteoarthritis

OBJECTIVE

To determine the prevalence of lumbar spine individual radiographic features (IRFs) of disc space narrowing (DSN), osteophytes (OST), and facet joint osteoarthritis (FOA); to describe the frequencies of demographic, clinical, and radiographic knee, hip, and hand osteoarthritis (OA) across lumbar spine IRFs; and to determine factors associated with lumbar spine IRFs.

METHODS

We conducted a cross-sectional study of 840 participants enrolled in the Johnston County Osteoarthritis Project (2003-2004). Sample-based prevalence estimates were generated for each lumbar spine IRF. The associations between lumbar spine IRFs and demographic, clinical, and peripheral joint OA were determined with logistic regression models.

RESULTS

Sample-based prevalence estimates were similar for DSN (57.6%) and FOA (57.9%) but higher for OST (88.1%), with significant differences across race and sex. Hand and knee OA frequencies increased across IRFs, whereas the effect was absent for hip OA. African Americans had lower odds of FOA (adjusted odds ratio [OR(adj) ] 0.45 [95% confidence interval (95% CI) 0.32-0.62]), while there was no racial association with DSN and OST. Low back symptoms were associated with DSN (OR(adj) 1.37 [95% CI 1.04-1.80]) but not OST or FOA. Knee OA was associated with OST (OR(adj) 1.62 [95% CI 1.16-2.27]) and FOA (OR(adj) 1.69 [95% CI 1.15-2.49]) but not DSN. Hand OA was associated with FOA (OR(adj) 1.67 [95% CI 1.20-2.28]) but not with DSN or OST. No associations were found with hip OA.

CONCLUSION

These findings underscore the importance of analyzing lumbar spine IRFs separately as the associations with demographic, clinical, and radiographic knee, hip, and hand OA differ widely.

Epidemiology of osteoarthritis and associated comorbidities

Osteoarthritis (OA) is the most common cause of walking-related disability among older adults in the United States, and the prevalence and incidence of OA are increasing rapidly. Systemic and local risk factors for knee OA have been identified, and obesity and joint injury appear to be the strongest risk factors that are both modifiable and have the potential for substantial impact on a population level. The risk factors for functional decline and disability in persons with symptomatic OA have been examined in relatively few studies. The course of functional decline in persons with symptomatic OA on a population level is generally one of stable to slowly deteriorating function, but on an individual level, many patients maintain function or improve during the first 3 years of follow-up. Obesity stands out as one of few modifiable risk factors of OA that also is a potentially modifiable predictor of functional decline. Physical activity also appears to have a substantial protective impact on future OA-related disability. Further epidemiologic studies and randomized controlled trials are needed to prioritize prevention through targeting these modifiable risk factors for OA and related disability.

Social determinants and osteoarthritis outcomes

Osteoarthritis (OA) is one of the most frequently occurring musculoskeletal diseases, posing a significant public health problem due to its impact on pain and disability. Traditional risk factors fail to account for all of the risk observed for OA outcomes. In recent years, our view of disease causation has broadened to include health risks that are created by an individual's socioeconomic circumstances. Early research into social determinants has focused on social position and explored factors related to the individual such as education, income and occupation. Results from these investigations suggest that low education attainment and nonprofessional occupation are associated with poorer arthritis outcomes. More recently, research has expanded to examine how one's neighborhood socioeconomic environment may be relevant to OA outcomes. This narrative review proposes a framework to help guide our understanding of how social context may interact with pathophysiological processes and individual-level variables to influence health outcomes in those living with OA.

Patterns of compartment involvement in tibiofemoral osteoarthritis in men and women and in whites and African Americans

OBJECTIVE

We conducted a cross-sectional study to describe the prevalence of tibiofemoral joint space narrowing (JSN) in medial and lateral compartments and assess whether it differs by sex and ethnic groups, and, if it does, to what extent such a difference is accounted for by knee malalignment.

METHODS

The Multicenter Osteoarthritis Study is an observational study of persons ages 50-79 years with either symptomatic knee osteoarthritis or high risk of disease. Knee radiographs were assessed for JSN in each tibiofemoral compartment. Mechanical axis angle was measured using full-extremity films. We compared the proportion of knees with medial compartment JSN and with lateral JSN between men and women, as well as between whites and African Americans, using a logistic regression model adjusting for covariates (race or sex and body mass index, age, education, and clinic site). We used generalized estimating equations to account for correlation between 2 knees within a person.

RESULTS

Of 5,202 knees (2,652 subjects), 1,532 (29.5%) had medial JSN and 427 (8.2%) had lateral JSN. Lateral JSN was more prevalent in the knees of women than in men (odds ratio [OR] 1.9, 95% confidence interval [95% CI] 1.5-2.4) and was also higher in the knees of African Americans than in whites (OR 2.4, 95% CI 1.7-3.3). Further adjustment for malalignment attenuated the OR for sex but not the OR for race.

CONCLUSION

Women and African Americans are more likely to have lateral JSN than men and whites, respectively. Valgus malalignment may contribute to the higher prevalence in women.

Racial differences in knee osteoarthritis pain: potential contribution of occupational and household tasks

OBJECTIVE

We examined whether occupational and household tasks contributed to differences in pain between African Americans and whites with radiographic knee osteoarthritis (OA).

METHODS

Participants from the Johnston County Osteoarthritis Project self-reported the frequency (often/always vs never/seldom/sometimes) of performing 9 occupational tasks involving lower extremity joint loading at their longest job (N = 868) and current job (N = 273), as well as 8 household tasks ever performed (N = 811) and currently being performed (N = 767). The associations of the numbers of occupational or household tasks with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale were first examined in simple linear regression models. If significantly associated with greater pain, each of these was included in adjusted linear regression models to examine whether the association of race with pain remained statistically significant.

RESULTS

African Americans reported significantly greater WOMAC pain scores than whites. Exposures to more occupational tasks at the longest job and the current job were associated with greater WOMAC pain scores (p < 0.01). The association of race with greater pain scores remained statistically significant when controlling for occupational tasks at the longest job, but was reduced by 26% and no longer significant when controlling for the number of current occupational tasks. Exposures to an increasing number of household tasks were associated with lower pain scores and were not further analyzed.

CONCLUSION

Current performance of physically demanding occupational tasks contributed to racial differences in pain severity among individuals with knee OA. Better workplace policies to accommodate OA-related limitations may help to reduce racial differences in pain.

The lack of correlation between radiographic findings and cartilage integrity

Total knee arthroplasty is a common treatment of osteoarthritis, although unicompartmental knee arthroplasties are frequently used to retain unaffected compartments. Joint space width (JSW) is a major factor in determining treatment. We examined the relationship between JSW and cartilage quality in 60 patients undergoing total knee arthroplasty to assess its accuracy in representing cartilage degradation. Radiographic JSW was recorded, whereas the unaffected compartment of each tibial plateau was examined postoperatively using Collins, Mankin, and Kellgren and Lawrence scores. No correlation was seen between visual or histologic grading and JSW. Histology more accurately represented cartilage quality, yet it is impractical to obtain preoperatively; thus, JSW is the main mode of assessment. However, using JSW solely to indicate unicompartmental knee arthroplasty may overlook disease in apparently unaffected compartments.

Osteoarthritis prevention

PURPOSE OF REVIEW

We discuss recent published epidemiologic data regarding risk factors for incident and progressive knee osteoarthritis and related knee pain to identify targets for primary and secondary prevention. We also discuss recently identified methodologic challenges to the study of knee osteoarthritis, particularly osteoarthritis progression.

RECENT FINDINGS

Recent epidemiologic studies and systematic reviews of knee osteoarthritis have confirmed that being overweight and obese, and knee injuries increase the risk for incident knee osteoarthritis. Biomechanical risk factors such as leg-length inequalities and malalignment require further study. Obesity also appears to play a role in accelerating osteoarthritis worsening. However, with the exception of malalignment, no risk factors for knee osteoarthritis progression have been identified. Novel approaches to the study of knee pain have demonstrated a strong association between structural abnormalities and knee pain, contrary to the 'so-called' structure-symptom discordance, as well as between fluctuations of knee pain with changes in specific structural lesions. A number of methodologic issues, including conditioning on an intermediate stage of disease and depletion of susceptibles may explain, in part, the difficulty in identifying risk factors for knee osteoarthritis.

SUMMARY

There is strong epidemiologic evidence that being overweight or obese and knee injury are associated with increased risk of developing knee osteoarthritis. Further study is required to confirm associations of leg-length inequality and malalignment with incident knee osteoarthritis. Few new risk factors for progression of knee osteoarthritis have been identified in the past few years. Without such knowledge, secondary prevention of osteoarthritis remains challenging.

Epidemiology of osteoarthritis

Osteoarthritis (OA) is the most common joint disorder in the United States. Symptomatic knee OA occurs in 10% men and 13% in women aged 60 years or older. The number of people affected with symptomatic OA is likely to increase due to the aging of the population and the obesity epidemic. OA has a multifactorial etiology, and can be considered the product of an interplay between systemic and local factors. Old age, female gender, overweight and obesity, knee injury, repetitive use of joints, bone density, muscle weakness, and joint laxity all play roles in the development of joint OA, particularly in the weight-bearing joints. Modifying these factors may reduce the risk of OA and prevent subsequent pain and disability.

Epidemiology of osteoarthritis

Osteoarthritis (OA) is the most common joint disorder in the United States. Symptomatic knee OA occurs in 10% men and 13% in women aged 60 years or older. The number of people affected with symptomatic OA is likely to increase due to the aging of the population and the obesity epidemic. OA has a multifactorial etiology, and can be considered the product of an interplay between systemic and local factors. Old age, female gender, overweight and obesity, knee injury, repetitive use of joints, bone density, muscle weakness, and joint laxity all play roles in the development of joint OA, particularly in the weight-bearing joints. Modifying these factors may reduce the risk of OA and prevent subsequent pain and disability.