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Upon completion of the chapter, the reader will be able to:
Describe the pathophysiologic principles of tissue injury and inflammation.
Identify the desired therapeutic outcomes for a patient with musculoskeletal injury or pain.
Identify the factors that guide selection of an analgesic or counterirritant for a particular patient.
Recommend appropriate nonpharmacologic and pharmacologic therapy for a patient with musculoskeletal injury or pain.
Design a patient education plan, including nonpharmacologic therapy and preventative strategies.
Develop a monitoring plan to assess treatment of a patient with a musculoskeletal disorder.
The musculoskeletal system consists of muscles, bones, joints, tendons, and ligaments. Disorders related to the musculoskeletal system often are classified by etiology. Acute soft-tissue injuries include strains and sprains of muscles and ligaments.1 Repeated movements in sports, exercise, work, or activities of daily living can lead to repetitive strain injury, where cumulative damage occurs to the muscles, ligaments, or tendons.2 Although tendonitis and bursitis can arise from acute injury, more commonly these conditions occur as a result of chronic stress.2,3 Other forms of chronic musculoskeletal pain, such as pain from rheumatoid arthritis (see Chapter 57) or osteoarthritis (see Chapter 58), are discussed elsewhere in this textbook.
EPIDEMIOLOGY AND ETIOLOGY
Musculoskeletal disorders are commonly self-treated, so true estimates of the incidence of both acute and chronic injury are difficult to obtain. In the United States, over 65 million musculoskeletal injuries occur each year, with 62% of episodes treated in ambulatory care offices.4 These disorders account for a large portion of medical care expenditures and are a leading cause of work absenteeism and disability, resulting in a substantial economic burden from lost productivity and lost wages.
Some musculoskeletal disorders arise from workplace injuries, including those induced by trauma or an acute overexertion and those induced by repetition and cumulative trauma.4 The most common sites of injury include the upper extremities (eg, hand, shoulder, and wrist), back, and lower extremity (eg, ankle, knee).
In older adults, musculoskeletal injuries may not be related to work but to daily life. Half of all musculoskeletal injuries occur in the home with falls being the most common cause for those aged 65 and older.4 In children and adolescents, fractures are more common than muscle and tendon injuries because growth spurts cause bones to weaken while the muscle–tendon unit tightens.2
Muscle injuries comprise the majority of sports-related injuries, and roughly half are related to overuse.4,5 The ankle is the most common site of sports injury.6 Activities that require rapid acceleration or pivoting at high speeds, such as basketball and soccer, pose the greatest risk of muscle sprain and acute injury.5,7