Osteoarthritis of the hip and occupational lifting

A biomechanical approach to musculoskeletal disease

The importance of biomechanical factors in musculoskeletal disease may be appreciated in the clinical characteristics and pathophysiology of joint degeneration in osteoarthritis. The biomechanical characteristics of the neuromuscular system are integral in determining the function and stability of the synovial joint and in mediating the biochemical structure of articular cartilage. Alterations in the neuromuscular system including abnormal gait and dynamic joint loading patterns as well as muscle strength and proprioception deficits have been independently studied and associated with osteoarthritis. These factors have close functional and physiological interactions. Nevertheless, specific relations between muscle strength and proprioception and their independent contributions to dynamic joint loading are not yet clear. Targeted interventions to moderate these factors may, in the future, be a therapeutic option for the management of osteoarthritis.

Osteoarthritis of the hip joint and farm work

BACKGROUND

Different types of farming and farm work were studied in relation to the occurrence of osteoarthritis of the hip joint in a cohort of farmers.

METHODS

A group of 427 farmers with hip joint osteoarthritis were identified together with a matched control group of farmers without hip or knee problems. All were invited to an interview and physical examination. After a dropout of 10%, and removing those who had had predisposing diseases or trauma, the observations for 369 pairs were available for analyses.

RESULTS

Farmers with larger dairy and swine confinement operations (sows) had an increased risk of acquiring osteoarthritis of the hip. In a logistic regression multivariate model, those who milked more than 40 cows daily had an increase in risk (OR = 4.5, 95% CI 1.9-11.0) in relation to those who did not work in dairy production. Those who had worked more than 5 hr daily in animal barns over a long period of time also had an increase in risk (OR = 13.3, 95% CI 1.2-145.0) in relation to those who did not work with animals. In another model, those who had large farm areas (>100 ha) had a significantly decreased risk (OR = 0.14, 95% CI 0.05-0.43) in relation to those who had smaller farm areas.

CONCLUSIONS

Farmers operating farms with large plant production area and few animal contacts had a significantly lower risk of incurring osteoarthritis of the hip than did farmers in general. The presence of animal production showed a significant positive relationship to the risk of developing hip joint osteoarthritis. Am. J. Ind. Med. 45:202-209, 2004.

Socioeconomic status, occupation, and risk of hospitalisation due to coxarthrosis in Denmark 1981-99

OBJECTIVES

To predict the relative risk and time trend in hospitalisation due to coxarthrosis (CA) among groups of different socioeconomic status and occupations in order to test existing aetiological hypotheses.

METHODS

Four consecutive cohorts of all gainfully employed Danish men were followed up for CA. Standardised hospitalisation ratios (SHR) and time trends were calculated.

RESULTS

Self employed men had an SHR due to CA of 140 (95% confidence interval (CI) 130 to 151) in 1994-99. It changed -1.2% (95% CI -2 to -0.4) annually from 1981 to 1999. Self employed farmers had an SHR of 286 (95% CI 262 to 313) during 1994-99, increasing 0.14% a year (95% CI -0.9 to 1.1) from 1981 to 1999. Unskilled men had an SHR of 121 (95% CI 113 to 130) in 1994-99. The SHR increased 1.6% annually (95% CI 0.7 to 2.4) from 1981 to 1999. Employed agricultural workers had an SHR of 189 (95% CI 158 to 227) from 1994 to 1999. The SHR increased 3.7% annually (95% CI 1.2 to 6.2) from 1981 to 1999.

CONCLUSIONS

The relative risk of hospitalisation due to CA was consistently high among farmers in four successive analyses spanning an 18 year period. The relative risks remained stable over time despite the fact that the number of farmers decreased. The risk increased among employed workers in agriculture and horticulture over that period, and an increased risk was also found among tractor drivers and a few other occupations.

Epidemiology of osteoarthritis: prevalence, risk factors and functional impact

Osteoarthritis (OA), the most common form of arthritis, is a major contributor to functional impairment and reduced independence in older adults. OA of the hip and knee are two of the most important causes of pain and physical disability in community-dwelling adults. Symptomatic hand OA is a common disease among the elderly, and impairs hand function, this impairment being largely mediated by pain. Like other chronic diseases, the etiology of OA is multifactorial, and several local and systemic risk factors have been identified. Differences in the prevalence of OA may be attributable to both genetic and life-style factors. Disease definition may be based upon clinical or radiographic criteria, although case definition should rely on radiographic features for epidemiological studies. This review focuses on the functional impact of the disease, describes geographic differences in prevalence rates, discusses disease definition criteria, and summarizes the most common risk factors, including age, associated with the risk of OA.

MR imaging of sports-related hip disorders

Hip arthroscopy is being used increasingly for the diagnosis and treatment of hip disorders. MR imaging performed with appropriate technical considerations may aid not only in preoperative planning but in the appropriate selection of patients, which tends to lead to better postoperative results. Although the painful hip is imaged most commonly by radiography, MR imaging is considered the next imaging test of choice for evaluation of most common hip abnormalities in athletes, including labral injuries, ligament injuries, osteochondral injuries, fractures, bursitis, and musculotendinous injuries. MR arthrography can be a particularly useful technique for dedicated assessment of hip joint internal derangements.

Hip pain onset in relation to cumulative workplace and leisure time mechanical load: a population based case-control study

OBJECTIVE

In an unselected community sample of adults, to assess the role and importance of exposure to mechanical factors both at work and leisure in the aetiology of hip pain.

METHOD

A population based prevalence case-control study. Cases and controls were identified from a population survey of 3847 subjects registered with two general practices in Cheshire, United Kingdom. All subjects received a postal questionnaire which inquired about hip pain during the past month. An occupational history was obtained, including exposure to each of seven physical demands. Information was also obtained on history of participation in eight common sporting activities.

RESULTS

88% of those invited to participate returned a completed questionnaire. The 352 subjects with hip pain were designated as cases, and the remaining 3002 subjects as controls. In people ever employed, hip pain was significantly associated with high cumulative workplace exposure (before onset) of walking long distances over rough ground, lifting/moving heavy weights, sitting for prolonged periods, walking long distances, frequent jumping between different levels, and standing for prolonged periods. Odds ratios (ORs) in the higher exposure categories ranged from 1.46 to 2.65. Cumulative exposure to three sporting activities was significantly associated with hip pain: track and field sports, jogging, and walking, with odds ratios varying between 1.57 to 1.94. On multivariate analysis three factors were independent predictors of hip pain onset: cumulative exposure of sitting for prolonged periods (higher exposure v not exposed: OR=1.82, 95% confidence interval (CI) 1.13 to 2.92), lifting weights >50 lb (23 kg) (OR=1.74, 95% CI 1.06 to 2.86) (both relating to the workplace), and walking as a leisure activity (OR=1.97, 95% CI 1.32 to 2.94). The population attributable risk associated with each of these activities was 21%, 13%, and 16%, respectively

CONCLUSIONS

Cumulative exposure to some workplace and sporting "mechanical" risk factors for hip osteoarthritis (OA) appear to be related to hip pain in general-some (but not all) have previously been related to hip OA. Because these are common workplace or leisure time activities their attributable risk is high.

Total hip replacement due to osteoarthritis: the importance of age, obesity, and other modifiable risk factors

We studied whether several modifiable factors were associated with the risk of total hip replacement due to hip osteoarthritis among women.We identified 568 women from the Nurses' Health Study who reported total hip replacement due to primary hip osteoarthritis on questionnaires from 1990 to 1996, using a validated algorithm. The relation of potential risk factors, such as age, body mass index, physical activity, smoking, alcohol intake, and hormone use, to hip replacement was assessed using pooled logistic regression models. Higher body mass index was associated with an increased risk of hip replacement due to osteoarthritis (P for trend = 0.0001). Compared with women in the lowest category of body mass index (<22 kg/m(2)), those in the highest category of body mass index (> or =35 kg/m(2)) had a twofold increased risk (95% confidence interval [CI]: 1.4 to 2.8), whereas those in the highest category of body mass index at age 18 years had more than a fivefold increased risk (95% CI: 2.5 to 10.7). Age also had a positive association; women aged > or =70 years were nine times more likely to have hip replacement than those aged <55 years (95% CI: 5.4 to 13.9). Recreational physical activity, smoking, alcohol use, and postmenopausal hormone use were not associated with an increased risk of hip replacement. In the Nurses' Health Study, higher body mass index and older age significantly increased the risk of total hip replacement due to osteoarthritis. Part of this risk appeared to be established early in life.

Osteoarthritis of the peripheral joints

Osteoarthritis (OA) is a complex process affecting many different joint areas in the body. From a pathophysiological point of view some features are crucial for the diagnosis, such as cartilage fibrillation and thinning, subchondral sclerosis and the presence of osteophytes. From a clinical perspective, OA is the most prevalent rheumatic joint disorder, causing pain and stiffness of the joints and, for the individual, impaired function and health status. The aim of this chapter is to present current knowledge of definitions of OA, its presence in different populations and in different joint areas (the back excluded). Furthermore, methods of diagnosing and delineating clinically relevant forms of OA, now and in the future, are presented as well as current knowledge of the risk factors for developing and the factors for preventing OA.

The contribution of type of daily activity to loading across the hip and knee joints in the elderly

OBJECTIVE

In the elderly, we evaluated loading across the hip or knee joints during different daily activities.

METHODS

Elderly people drawn from the community entering an exercise study underwent a full kinetic and kinematics analysis of five different activities, standing, walking, arising from a chair, going downstairs and bending over. Inverse dynamic equations were used to compute forces and torques across the knees and hips during all of these activities.

RESULTS

132 elderly people, mean age 75, participated. Compressive forces across the knees and hips were, by far, the greatest vector forces and were highest during stair descent and, to a lesser extent, during walking. Compressive forces were lowest during standing. The highest moments were flexion and adduction moments, and these were maximal during stair descent.

CONCLUSION

Of the five activities we studied, descending stairs was associated with the highest calculated forces and torques across the knees and hips, and that may account for its tendency to cause joint symptoms and for its possible association with osteoarthritis incidence.

An update on the relationship between occupational factors and osteoarthritis of the hip and knee

This study reviews articles published in 2000 and 2001 about occupational physical activities as risk factors for osteoarthritis (OA) of the knee and hip. Six studies were identified in MEDLINE and EMBASE; five case-control studies and one cross-sectional study. Criteria for OA were: (on the waiting list for) joint replacement or (symptomatic) radiologic OA. Exposure was assessed by structured interviews or self-administered questionnaires. Job titles or details on specific physical activities were used as determinants. The authors determine that information bias and nondifferential misclassification, with respect to occupational risk factors, cannot be excluded. Relevant confounding factors were adequately taken into account. Even though response rates were high, nonresponse bias may still have an influence, although its impact cannot be assessed accurately. Within these constraints the studies gave further evidence to support the role of jobs and occupational physical activities on the occurrence of OA.

Risk factors for total hip replacement due to primary osteoarthritis: a cohort study in 50,034 persons

OBJECTIVE

To identify prospectively the possible risk factors for total hip replacement (THR) due to primary osteoarthritis in a large cohort.

METHODS

Data from a cardiovascular screening were matched with 9 years of national data on THR. Mean age at the start of followup was 54.9 years, and the 50,034 participants were followed up for an average of 9 years. During followup, 672 persons had a first THR due to primary osteoarthritis.

RESULTS

We found dose-response associations between body mass index (BMI), body weight, and the level of physical activity at work and THR for primary osteoarthritis. The highest versus the lowest quarter of BMI had a relative risk of 2.0 (95% confidence interval [95% CI] 1.4-2.9) among men and 3.0 (95% CI 2.1-4.1) among women. The highest versus the lowest quarter of body weight had a relative risk of 2.1 (95% CI 1.4-3.2) among men and 3.4 (95% CI 2.4-4.9) among women. Intensive versus sedentary physical activity at work had a relative risk of 2.1 (95% CI 1.5-3.0) among men and 2.1 (95% CI 1.3-3.3) among women. No association was found between physical activity in leisure and THR for primary osteoarthritis.

CONCLUSION

Intensive physical activity at work and a high BMI each contribute significantly to the overall risk of undergoing THR due to primary osteoarthritis. Lowering the exposure to these risk factors may substantially reduce the need for hip replacement.

Stair negotiation in older people: a review

Locomotion on stairs is among the most challenging and hazardous activities of daily living for older individuals. This is evidenced by the reports that stair falls account for more than 10% of fatal fall accidents. The demands that stairs place on the musculoskeletal and cardiovascular systems are compounded by the need for input from the somatosensory, visual, and vestibular systems at various stages in the task. Many of these collaborating systems deteriorate with aging, thus increasing the difficulty and risk of failure in a task that inherently involves exposure to significant danger. The task itself varies in its degree of challenge depending on many structural and environmental factors that are outside the control of the stair user. This review explores existing literature in the area of stair negotiation by older persons in an effort to define the key factors associated with difficulty and safety on stairs and to interpret these findings in the light of possible interventions that could increase stair safety. Further research is needed to ensure that current recommendations for stair design are suitable for older stair users. A Glossary of Terms is also provided.

Osteoarthritis: Update on Pathology, Pathogenesis and Treatment

Osteoarthritis (OA) is a joint disorder that is characterized by increased degradative and decreased synthetic processes. The pathogenetic factors that have been demonstrated to influence the progression of OA are cytokines and nitric oxide. This new information serves to further elucidate the factors involved in the etiology of osteoarthritis and will aid in the development of pharmacological tools to treat this disease. As our understanding of the pathogenesis of OA grows, so does our appreciation that it is not simply a disease of passive joint degeneration. Unfortunately, therapies aimed at modifying the progression of the disease remain frustratingly difficult to identify. Primary therapy for OA thus is still largely aimed at controlling the symptoms of the disease while minimizing drug side effects. New agents with the potential to slow disease progression are beginning to emerge however. These will be discussed along with the agents that should be used first line to control symptoms.