Clinical risk factors associated with radiographic osteoarthritis progression among people with knee pain: a longitudinal study.

BACKGROUND: The aim of this study was to identify modifiable clinical factors associated with radiographic osteoarthritis progression over 1 to 2 years in people with painful medial knee osteoarthritis. METHODS: A longitudinal study was conducted within a randomised controlled trial, the "Long-term Evaluation of Glucosamine Sulfate" (LEGS study). Recruitment occurred in 2007-2009, with 1- and 2-year follow-up assessments by blinded assessors. Community-dwelling people with chronic knee pain (≥4/10) and medial tibiofemoral narrowing (but retaining >2mm medial joint space width) on radiographs were recruited. From 605 participants, follow-up data were available for 498 (82%, mean [sd] age 60 [8] years). Risk factors evaluated at baseline were pain, physical function, use of non-steroidal anti-inflammatory drugs (NSAIDs), statin use, not meeting physical activity guidelines, presence of Heberden's nodes, history of knee surgery/trauma, and manual occupation. Multivariable logistic regression analysis was conducted adjusting for age, sex, obesity, high blood pressure, allocation to glucosamine and chondroitin treatment, and baseline structural disease severity (Kellgren and Lawrence grade, joint space width, and varus alignment). Radiographic osteoarthritis progression was defined as joint space narrowing ≥0.5mm over 1 to 2 years (latest follow-up used where available). RESULTS: Radiographic osteoarthritis progression occurred in 58 participants (12%). Clinical factors independently associated with radiographic progression were the use of NSAIDs, adjusted odds ratios (OR) and 95% confidence intervals (CI) 2.05 (95% CI 1.1 to 3.8), and not meeting physical activity guidelines, OR 2.07 (95% CI 0.9 to 4.7). CONCLUSIONS: Among people with mild radiographic knee osteoarthritis, people who use NSAIDs and/or do not meet physical activity guidelines have a greater risk of radiographic osteoarthritis progression. TRIAL REGISTRATION: ClinicalTrials.gov , NCT00513422 . This original study trial was registered a priori, on August 8, 2007. The current study hypothesis arose before inspection of the data.

Post-Acute Rehabilitation After Total Knee Replacement: A Multicenter Randomized Clinical Trial Comparing Long-Term Outcomes.

OBJECTIVE: To evaluate the long-term benefit of providing a post-acute, outpatient group exercise program for patients following primary total knee replacement (TKR) surgery for osteoarthritis. METHODS: A multicenter randomized clinical trial was conducted in 12 Australian public and private hospital centers. A total of 422 participants, ages 45-75 years, were randomly allocated prior to hospital discharge to the post-acute group exercise program or to usual care and were assessed at 6 weeks, 6 months, and 12 months after surgery. The main outcomes were operated knee pain and activity limitations at 12 months using the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire. Secondary outcomes included health-related quality of life (Short Form 12 health survey), knee extension and flexion strength, stair-climb power, 50-foot walk speed, and active knee range of motion. RESULTS: While both allocation groups achieved significant improvements in knee pain and activity limitations over the 12-month followup period, there were no significant differences in these main outcomes, or in the secondary physical performance measures, between the 2 treatment allocations. Twelve months after TKR, 69% and 72% of participants allocated to post-acute exercise and usual acute care, respectively, were considered to be treatment-responders. While population normative values for self-report measures of pain, activity limitation, and health-related quality of life were attained 12 months after TKR, marked deficits in physical performance measures remained. CONCLUSION: Providing access to a post-acute group exercise program did not result in greater reductions in long-term knee pain or activity limitations than usual care. Patients undergoing primary TKR retain marked physical performance deficits 12 months after surgery.

Glucosamine and chondroitin for knee osteoarthritis: a double-blind randomised placebo-controlled clinical trial evaluating single and combination regimens.

OBJECTIVE: To determine if the dietary supplements, glucosamine and/or chondroitin, result in reduced joint space narrowing (JSN) and pain among people with symptomatic knee osteoarthritis. METHODS: A double-blind randomised placebo-controlled clinical trial with 2-year follow-up. 605 participants, aged 45-75 years, reporting chronic knee pain and with evidence of medial tibio-femoral compartment narrowing (but retaining >2 mm medial joint space width) were randomised to once daily: glucosamine sulfate 1500 mg (n=152), chondroitin sulfate 800 mg (n=151), both dietary supplements (n=151) or matching placebo capsules (n=151). JSN (mm) over 2 years was measured from digitised knee radiographs. Maximum knee pain (0-10) was self-reported in a participant diary for 7 days every 2 months over 1 year. RESULTS: After adjusting for factors associated with structural disease progression (gender, body mass index (BMI), baseline structural disease severity and Heberden's nodes), allocation to the dietary supplement combination (glucosamine-chondroitin) resulted in a statistically significant (p=0.046) reduction of 2-year JSN compared to placebo: mean difference 0.10 mm (95% CI 0.002 mm to 0.20 mm); no significant structural effect for the single treatment allocations was detected. All four allocation groups demonstrated reduced knee pain over the first year, but no significant between-group differences (p=0.93) were detected. 34 (6%) participants reported possibly-related adverse medical events over the 2-year follow-up period. CONCLUSIONS: Allocation to the glucosamine-chondroitin combination resulted in a statistically significant reduction in JSN at 2 years. While all allocation groups demonstrated reduced knee pain over the study period, none of the treatment allocation groups demonstrated significant symptomatic benefit above placebo. TRIAL REGISTRATION CLINICALTRIALSGOV IDENTIFIER: NCT00513422; http://www.clinicaltrials.gov.

The global burden of hip and knee osteoarthritis: estimates from the global burden of disease 2010 study.

OBJECTIVE: To estimate the global burden of hip and knee osteoarthritis (OA) as part of the Global Burden of Disease 2010 study and to explore how the burden of hip and knee OA compares with other conditions. METHODS: Systematic reviews were conducted to source age-specific and sex-specific epidemiological data for hip and knee OA prevalence, incidence and mortality risk. The prevalence and incidence of symptomatic, radiographic and self-reported hip or knee OA were included. Three levels of severity were defined to derive disability weights (DWs) and severity distribution (proportion with mild, moderate and severe OA). The prevalence by country and region was multiplied by the severity distribution and the appropriate disability weight to calculate years of life lived with disability (YLDs). As there are no deaths directly attributed to OA, YLDs equate disability-adjusted life years (DALYs). RESULTS: Globally, of the 291 conditions, hip and knee OA was ranked as the 11th highest contributor to global disability and 38th highest in DALYs. The global age-standardised prevalence of knee OA was 3.8% (95% uncertainty interval (UI) 3.6% to 4.1%) and hip OA was 0.85% (95% UI 0.74% to 1.02%), with no discernible change from 1990 to 2010. Prevalence was higher in females than males. YLDs for hip and knee OA increased from 10.5 million in 1990 (0.42% of total DALYs) to 17.1 million in 2010 (0.69% of total DALYs). CONCLUSIONS: Hip and knee OA is one of the leading causes of global disability. Methodological issues within this study make it highly likely that the real burden of OA has been underestimated. With the aging and increasing obesity of the world's population, health professions need to prepare for a large increase in the demand for health services to treat hip and knee OA.

Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.

BACKGROUND: Non-fatal health outcomes from diseases and injuries are a crucial consideration in the promotion and monitoring of individual and population health. The Global Burden of Disease (GBD) studies done in 1990 and 2000 have been the only studies to quantify non-fatal health outcomes across an exhaustive set of disorders at the global and regional level. Neither effort quantified uncertainty in prevalence or years lived with disability (YLDs). METHODS: Of the 291 diseases and injuries in the GBD cause list, 289 cause disability. For 1160 sequelae of the 289 diseases and injuries, we undertook a systematic analysis of prevalence, incidence, remission, duration, and excess mortality. Sources included published studies, case notification, population-based cancer registries, other disease registries, antenatal clinic serosurveillance, hospital discharge data, ambulatory care data, household surveys, other surveys, and cohort studies. For most sequelae, we used a Bayesian meta-regression method, DisMod-MR, designed to address key limitations in descriptive epidemiological data, including missing data, inconsistency, and large methodological variation between data sources. For some disorders, we used natural history models, geospatial models, back-calculation models (models calculating incidence from population mortality rates and case fatality), or registration completeness models (models adjusting for incomplete registration with health-system access and other covariates). Disability weights for 220 unique health states were used to capture the severity of health loss. YLDs by cause at age, sex, country, and year levels were adjusted for comorbidity with simulation methods. We included uncertainty estimates at all stages of the analysis. FINDINGS: Global prevalence for all ages combined in 2010 across the 1160 sequelae ranged from fewer than one case per 1 million people to 350,000 cases per 1 million people. Prevalence and severity of health loss were weakly correlated (correlation coefficient -0·37). In 2010, there were 777 million YLDs from all causes, up from 583 million in 1990. The main contributors to global YLDs were mental and behavioural disorders, musculoskeletal disorders, and diabetes or endocrine diseases. The leading specific causes of YLDs were much the same in 2010 as they were in 1990: low back pain, major depressive disorder, iron-deficiency anaemia, neck pain, chronic obstructive pulmonary disease, anxiety disorders, migraine, diabetes, and falls. Age-specific prevalence of YLDs increased with age in all regions and has decreased slightly from 1990 to 2010. Regional patterns of the leading causes of YLDs were more similar compared with years of life lost due to premature mortality. Neglected tropical diseases, HIV/AIDS, tuberculosis, malaria, and anaemia were important causes of YLDs in sub-Saharan Africa. INTERPRETATION: Rates of YLDs per 100,000 people have remained largely constant over time but rise steadily with age. Population growth and ageing have increased YLD numbers and crude rates over the past two decades. Prevalences of the most common causes of YLDs, such as mental and behavioural disorders and musculoskeletal disorders, have not decreased. Health systems will need to address the needs of the rising numbers of individuals with a range of disorders that largely cause disability but not mortality. Quantification of the burden of non-fatal health outcomes will be crucial to understand how well health systems are responding to these challenges. Effective and affordable strategies to deal with this rising burden are an urgent priority for health systems in most parts of the world. FUNDING: Bill & Melinda Gates Foundation.

Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.

BACKGROUND: Measuring disease and injury burden in populations requires a composite metric that captures both premature mortality and the prevalence and severity of ill-health. The 1990 Global Burden of Disease study proposed disability-adjusted life years (DALYs) to measure disease burden. No comprehensive update of disease burden worldwide incorporating a systematic reassessment of disease and injury-specific epidemiology has been done since the 1990 study. We aimed to calculate disease burden worldwide and for 21 regions for 1990, 2005, and 2010 with methods to enable meaningful comparisons over time. METHODS: We calculated DALYs as the sum of years of life lost (YLLs) and years lived with disability (YLDs). DALYs were calculated for 291 causes, 20 age groups, both sexes, and for 187 countries, and aggregated to regional and global estimates of disease burden for three points in time with strictly comparable definitions and methods. YLLs were calculated from age-sex-country-time-specific estimates of mortality by cause, with death by standardised lost life expectancy at each age. YLDs were calculated as prevalence of 1160 disabling sequelae, by age, sex, and cause, and weighted by new disability weights for each health state. Neither YLLs nor YLDs were age-weighted or discounted. Uncertainty around cause-specific DALYs was calculated incorporating uncertainty in levels of all-cause mortality, cause-specific mortality, prevalence, and disability weights. FINDINGS: Global DALYs remained stable from 1990 (2·503 billion) to 2010 (2·490 billion). Crude DALYs per 1000 decreased by 23% (472 per 1000 to 361 per 1000). An important shift has occurred in DALY composition with the contribution of deaths and disability among children (younger than 5 years of age) declining from 41% of global DALYs in 1990 to 25% in 2010. YLLs typically account for about half of disease burden in more developed regions (high-income Asia Pacific, western Europe, high-income North America, and Australasia), rising to over 80% of DALYs in sub-Saharan Africa. In 1990, 47% of DALYs worldwide were from communicable, maternal, neonatal, and nutritional disorders, 43% from non-communicable diseases, and 10% from injuries. By 2010, this had shifted to 35%, 54%, and 11%, respectively. Ischaemic heart disease was the leading cause of DALYs worldwide in 2010 (up from fourth rank in 1990, increasing by 29%), followed by lower respiratory infections (top rank in 1990; 44% decline in DALYs), stroke (fifth in 1990; 19% increase), diarrhoeal diseases (second in 1990; 51% decrease), and HIV/AIDS (33rd in 1990; 351% increase). Major depressive disorder increased from 15th to 11th rank (37% increase) and road injury from 12th to 10th rank (34% increase). Substantial heterogeneity exists in rankings of leading causes of disease burden among regions. INTERPRETATION: Global disease burden has continued to shift away from communicable to non-communicable diseases and from premature death to years lived with disability. In sub-Saharan Africa, however, many communicable, maternal, neonatal, and nutritional disorders remain the dominant causes of disease burden. The rising burden from mental and behavioural disorders, musculoskeletal disorders, and diabetes will impose new challenges on health systems. Regional heterogeneity highlights the importance of understanding local burden of disease and setting goals and targets for the post-2015 agenda taking such patterns into account. Because of improved definitions, methods, and data, these results for 1990 and 2010 supersede all previously published Global Burden of Disease results. FUNDING: Bill & Melinda Gates Foundation.

Hip and knee pain: role of occupational factors.

Many people rely economically on occupations involving high loading of the hip or knee joints for lengthy periods, possibly placing them at increased risk of developing chronic pain in these joints. There is a growing body of evidence from large longitudinal cohort studies, case-control studies and population-based surveys that certain occupations, or having work involving considerable heavy lifting, kneeling or squatting, may be associated with increased risk of symptomatic hip or knee osteoarthritis and joint replacement surgery. Only a few studies have evaluated the effectiveness of specific workplace strategies to reduce this risk. Identifying modifiable workplace risk factors and implementing feasible and accessible preventative strategies will be of great public health significance in the next decade.

The epidemiology of osteoarthritis in Asia.

Worldwide, osteoarthritis (OA) is estimated to be the fourth leading cause of disability. Most of this disability burden is attributable to the involvement of the hips or the knees. OA is strongly associated with ageing and the Asian region is ageing rapidly. Further, OA has been associated with heavy physical occupational activity, a required livelihood for many people living in rural communities in developing countries. Unfortunately, joint replacement surgery, an effective intervention for people with severe OA involving the hips or knees, is inaccessible to most people in these regions. On the other hand, obesity, another major risk factor, may be less prevalent, although it is on the increase. Determining region-specific OA prevalence and risk factor profiles will provide important information for planning future cost-effective preventive strategies and health care services. An update of what is currently known about the prevalence of hip and knee OA from population-based studies conducted in the Asian region is presented in this review. Many of the recent studies have conducted comparisons between urban and rural areas and poor and affluent communities. The results of Asian-based studies evaluating risk factors from population-based cohorts or case-control studies, and the current evidence on OA morbidity burden in Asia is also outlined.

Osteoarthritis.

Internationally, prevalence estimates for osteoarthritis show wide variability depending on the age and sex of the studied population, the method of case identification used, and the specificity of joint sites included. Currently, there is no generally agreed "gold standard" for identifying cases of osteoarthritis in epidemiologic studies. Despite this lack of standardisation, it is consistently demonstrated in population-based studies, worldwide, that osteoarthritis prevalence is positively associated with increasing age and that the greatest disease burden is attributable to involvement of the hip or knee joints. To estimate the true burden of osteoarthritis involving the hips or knees, comprehensive accounting of all associated morbidity is required. The identification of modifiable risk factors for disease incidence and progression is needed.

Changes in long jump take-off technique with increasing run-up speed.

The aim of this study was to determine the influence of run-up speed on take-off technique in the long jump. Seventy-one jumps by an elite male long jumper were recorded in the sagittal plane by a high-speed video camera. A wide range of run-up speeds was obtained using direct intervention to set the length of the athlete's run-up. As the athlete's run-up speed increased, the jump distance and take-off speed increased, the leg angle at touchdown remained almost unchanged, and the take-off angle and take-off duration steadily decreased. The predictions of two previously published mathematical models of the long jump take-off are in reasonable agreement with the experimental data.

Optimum take-off angle in the long jump.

In this study, we found that the optimum take-off angle for a long jumper may be predicted by combining the equation for the range of a projectile in free flight with the measured relations between take-off speed, take-off height and take-off angle for the athlete. The prediction method was evaluated using video measurements of three experienced male long jumpers who performed maximum-effort jumps over a wide range of take-off angles. To produce low take-off angles the athletes used a long and fast run-up, whereas higher take-off angles were produced using a progressively shorter and slower run-up. For all three athletes, the take-off speed decreased and the take-off height increased as the athlete jumped with a higher take-off angle. The calculated optimum take-off angles were in good agreement with the athletes' competition take-off angles.