Musculoskeletal complaints account for >315 million outpatient visits per year and nearly 20% of all outpatient visits in the United States. The Centers for Disease Control and Prevention estimate that 22% (46 million) of the U.S. population has physician-diagnosed arthritis and 19 million have significant functional limitation. While many patients will have self-limited conditions requiring minimal evaluation and only symptomatic therapy and reassurance, specific musculoskeletal presentations or their persistence may herald a more serious condition that requires further evaluation or laboratory testing to establish a diagnosis. The goal of the musculoskeletal evaluation is to formulate a differential diagnosis that leads to an accurate diagnosis and timely therapy, while avoiding excessive diagnostic testing and unnecessary treatment (Table 331-1). There are several urgent conditions that must be diagnosed promptly to avoid significant morbid or mortal sequelae. These “red flag” diagnoses include septic arthritis, acute crystal-induced arthritis (e.g., gout), and fracture. Each may be suspected by its acute onset and monarticular or focal musculoskeletal pain (see below).
Table 331-1 Evaluation of Patients with Musculoskeletal Complaints |Favorite Table|Download (.pdf)
Table 331-1 Evaluation of Patients with Musculoskeletal Complaints
|Timely provision of therapy|
|Avoidance of unnecessary diagnostic testing|
|Anatomic localization of complaint (articular vs. nonarticular)|
|Determination of the nature of the pathologic process(inflammatory vs. noninflammatory)|
|Determination of the extent of involvement (monarticular,polyarticular, focal, widespread)|
|Determination of chronology (acute vs. chronic)|
|Consider the most common disorders first|
|Formulation of a differential diagnosisentry|
Individuals with musculoskeletal complaints should be evaluated with a thorough history, a comprehensive physical and musculo-skeletal examination, and, if appropriate, laboratory testing. The initial encounter should determine whether the musculoskeletal complaint signals a red flag condition (septic arthritis, gout, or fracture) or not. The evaluation should proceed to ascertain if the complaint is (1) articular or nonarticular in origin, (2) inflammatory or noninflammatory in nature, (3) acute or chronic in duration, and (4) localized (monarticular) or widespread (polyarticular) in distribution.
With such an approach and an understanding of the pathophysiologic processes, the musculoskeletal complaint or presentation can be characterized (e.g., acute inflammatory monarthritis or a chronic noninflammatory, nonarticular widespread pain) to narrow the diagnostic possibilities. A diagnosis can be made in the vast majority of individuals. However, some patients will not fit immediately into an established diagnostic category. Many musculoskeletal disorders resemble each other at the outset, and some may take weeks or months to evolve into a readily recognizable diagnostic entity. This consideration should temper the desire to establish a definitive diagnosis at the first encounter.
The musculoskeletal evaluation must discriminate the anatomic origin(s) of the patient's complaint. For example, ankle pain can result from a variety of pathologic conditions involving disparate anatomic structures, including gonococcal arthritis, calcaneal fracture, Achilles tendinitis, plantar fasciitis, cellulitis, and peripheral or entrapment neuropathy. Distinguishing between articular and nonarticular conditions requires a careful and detailed examination. Articular ...