History

physically active patients, with as many as 54 percent of athletes having some degree of knee pain each year.1 Knee pain can be a source of significant disability, restricting the ability to work or perform activities of daily living. The knee is a complex structure (Figure 1),2 and its evaluation can present a challenge to the family physician. The differential diagno-sis of knee pain is extensive but can be nar-rowed with a detailed history, a focused phys-ical examination and, when indicated, the selective use of appropriate imaging and labo-ratory studies. Part I of this two-part article provides a systematic approach to evaluating the knee, and part II3 discusses the differential diagnosis of knee pain