Musculoskeletal diseases are diseases of the locomotor system, which includes muscles, bones, joints and adjacent connective tissues. Musculoskeletal disorders include more than 150 different conditions that affect the musculoskeletal system and are characterized by disorders of the muscles, bones, joints and adjacent connective tissues that lead to temporary or lifelong limitations in functioning. Musculoskeletal injuries are typically characterized by pain, often persistent, limitations of mobility and dexterity, which reduces people's ability to work, or it leads to early exit from work, lower levels of well-being and reduced ability to participate in society. Pain that occurs in the musculoskeletal system is the most common form of non-cancer pain.
Musculoskeletal disorders are a major contributor to disability worldwide, with low back pain being the single leading cause of disability in 160 countries. Due to population growth and aging, the number of people living with musculoskeletal disorders and related functional limitations is increasing rapidly.
Musculoskeletal diseases occur throughout life - from childhood to old age. They range from conditions that arise suddenly and are short-term (such as fractures, sprains and strains, associated with pain and functional limitations) to long-term conditions such as chronic primary low back pain and osteoarthritis.
Musculoskeletal diseases include conditions that affect:
- joints, such as osteoarthritis, rheumatoid arthritis, psoriatic arthritis, gout, spondyloarthritis;
- bones, e.g. osteoporosis, osteopenia and associated fragility fractures, traumatic fractures;
- muscles, e.g. sarcopenia;
- multiple body areas or systems such as regional (e.g. back and neck pain) and widespread (e.g. fibromyalgia) pain conditions,
- inflammatory diseases, such as connective tissue diseases and vasculitis, which have musculoskeletal manifestations, for example systemic lupus erythematosus, or amputation due to disease or trauma.
Musculoskeletal disorders are also the largest contributor to the global need for rehabilitation. They are among the largest contributors to the need for rehabilitation services in children and represent approximately two-thirds of all adults requiring rehabilitation. Musculoskeletal conditions often coexist with other NCDs and increase the risk of other NCDs such as cardiovascular disease. People with musculoskeletal conditions are also at higher risk of developing mental health problems.
Occurrence
A recent analysis of Global Burden of Disease (GBD) data from 2019 showed that approximately 1.71 billion people worldwide live with musculoskeletal conditions, including low back pain, neck pain, fractures, other injuries, osteoarthritis, amputation and rheumatoid arthritis. While the prevalence of musculoskeletal disorders varies by age and diagnosis, people of all ages worldwide are affected. In terms of the number of people, high-income countries are most affected - 441 million, followed by countries in the Western Pacific region with 427 million, in the South-East Asia region with 369 million affected. Musculoskeletal diseases are also the largest contributor to Years of healthy life Lost due to Disability (YLD) worldwide, with approximately 149 million YLDs, accounting for 17% of all YLDs worldwide.
Low back pain is a major contributor to the overall burden of musculoskeletal conditions (570 million prevalent cases worldwide, accounting for 7.4% of global YLDs). Other factors contributing to the overall burden of musculoskeletal disease include fractures in 440 million people worldwide (26 million YLD), osteoarthritis (528 million people; 19 million YLD), neck pain (222 million people; 22 million YLD), amputations (180 million people; 5.5 million YLD), rheumatoid arthritis (18 million people; 2.4 million YLD), gout (54 million people; 1.7 million YLD), other musculoskeletal diseases (453 million people; 38 million YLD).
While the prevalence of musculoskeletal disorders increases with age, younger people are also affected, often during their peak income years. For example, childhood autoimmune inflammatory conditions such as juvenile arthritis affect children's development, while lower back pain is a leading cause of early absenteeism. The societal impact of early retirement in terms of direct health care costs and indirect costs (ie absenteeism from work or lost productivity) is enormous. Projections show that the number of people with low back pain will increase in the future, and even more rapidly in low- and middle-income countries.
Cause of malfunctions of the support-movement system
When a person is exposed to risk factors for damage to the musculoskeletal system, he begins to feel tired. When fatigue exceeds the body's regenerative system, it develops a musculoskeletal imbalance. Over time, when fatigue continues to outpace recovery and musculoskeletal imbalance persists, a musculoskeletal disorder develops. These risk factors can be divided into two categories:
- ergonomic risk factors related to work a
- individual risk factors.
Individual risk factors
Human beings are multidimensional. If we limit ourselves to a unique cause of musculoskeletal injuries, we limit our ability to develop a prevention strategy that will address the multidimensional worker. We need to address workplace risk factors as well as individual risk factors. Individual risk factors include:
- Poor individual work practices. Workers who use poor work practices, body mechanics, and lifting techniques introduce unnecessary risk factors that can contribute to musculoskeletal injury. These incorrect practices create unnecessary stress on their bodies, which increases fatigue and reduces their body's ability to recover properly.
- General poor health habits. Workers who smoke, drink excessively, are obese or exhibit a number of other poor health habits put themselves at risk not only for musculoskeletal disorders, but also for other chronic diseases that shorten their health.
- Poor rest and recovery. Musculoskeletal injuries develop when fatigue overwhelms the workers' recovery system, causing musculoskeletal imbalances. Workers who do not receive adequate rest and recovery are at greater risk.
- Poor nutrition, fitness, and hydration. In developed countries, an alarming number of people are malnourished, dehydrated, and at such a poor level of physical fitness that walking up a single flight of stairs takes many people out of breath. Workers who do not take care of their bodies are at higher risk of developing musculoskeletal and chronic health problems.
Exposure to these individual risk factors puts workers at a higher level of risk of damage to the musculoskeletal system.
Work-related risk factors
Workplace design plays a key role in the development of musculoskeletal disorders. When a worker is asked to perform work that is beyond their body's capabilities and limitations, they are being asked to put their musculoskeletal system at risk. In these situations, an objective evaluation of the design of the workplace (or a specific workplace) tells us that the worker's body recovery system will not be able to keep up with the fatigue that will be caused by the work. The evaluation will tell us that ergonomic risk factors are present, the worker is at risk of developing an imbalance of the locomotor apparatus, and thus a musculoskeletal disorder becomes an immediate reality.
Risk ergonomic factors
There are three primary ergonomic risk factors:
- Frequent repetition of tasks. Many work tasks and cycles are repetitive in nature and are often driven by hourly or daily production targets and work processes. High repetition of tasks in combination with other risk factors, such as high force and/or awkward positions, can contribute to the formation of damage to the musculoskeletal system. A task is considered highly repetitive if the cycle time is 30 seconds or less.
- Strong exertion. Many work tasks require a high force load on the human body. Muscular effort increases in response to high strength demands, increasing the associated fatigue that can lead to damage to the musculoskeletal system.
- Repetitive or persistent improper posture. An awkward posture puts excessive force on the joints and overloads the muscles and tendons around the affected joint.
The joints of the body are most effective when they work closest to the joint's mid range of motion. The risk of damage to the musculoskeletal system increases if joints are worked outside of this mid-range repeatedly or for extended periods of time without adequate recovery time.
Exposure to these risk factors in the workplace exposes workers to a higher level of risk of damage to the musculoskeletal system. High task repetition, heavy exertion, and repetitive/sustained awkward postures fatigue the worker's body beyond its ability to recover, leading to musculoskeletal imbalances and eventual damage to the musculoskeletal system.
According to SR legislation, the combination of inappropriate work risk factors and ergonomic load is listed as long-term excessive unilateral load of the upper limbs - which is a component of the physical load of the upper limbs that can cause excessive load on the upper limbs and can lead to damage to health, including the development of disease from long-term, excessive and unilateral load on the upper limbs. The degree of load on the upper limbs under the influence of long-term excessive unilateral load depends on: a) the time of exposure and inclusion of recovery breaks at work to recover from long-term excessive unilateral load of the upper limbs, which, together with other conditions, affect the long-term load-bearing capacity, b) muscle strength, which together with other conditions affects the excessive load, c) the frequency of movements, the position of the upper limbs and the monotony of work tasks, which, together with other conditions, affect the one-sidedness of the load.
Conclusion
If we want to lay the foundations for a strategy to prevent musculoskeletal injuries, it is important to understand what musculoskeletal injuries are and what causes them. Thanks to this knowledge, we will be able to allocate our time, attention and resources as efficiently as possible to prevent damage to the musculoskeletal system.
If a worker uses poor work practices, has poor health habits, doesn't get adequate rest and recovery, and doesn't take care of their body with a good diet and fitness regimen, they are at greater risk of fatigue overtaking their regenerative system. A poor overall health profile exposes them to a greater risk of musculoskeletal imbalances, or damage to the support-movement system.
Authors: *MDr. Jana Popaďáková, Department of Neurology, Hospital Svet zdravia Vranov nad Topľou doc. MUDr. Kvetoslava Rimárová, CSc., mim. prof., Institute of Public Health and Hygiene, UPJŠ in Košice prof. MUDr. Erik Dorko, PhD., MPH., Institute of Public Health and Hygiene, UPJŠ in Košice Mgr. Lívia Kaňuková, Institute of Public Health and Hygiene, UPJŠ in Košice***
Work supported by 2 KEGA grant projects of the Ministry of Education, Science, Research and Sport of the SR KEGA: KEGA 008 UPJŠ-4/2020; KEGA 010UPJŠ-4/2021.
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Decree of the Ministry of Health of the Slovak Republic no. 542/2007 Coll. on the details of health protection against physical workload at work, psychological workload and sensory workload at work.