History and physical examination of the patellofemoral joint with patellar instability

Patellar instability is a common source of anterior knee pain among young, active individuals, and is more common in females than in males. There is usually an underlying malalignment of the lower extremity, which may contribute to the patient's complaints of "giving way." A careful, deliberate history and physical examination are instrumental in the diagnosis of a patient with anterior knee pain secondary to instability. The history should include the initial onset of the patient's symptoms, the exacerbating and relieving maneuvers, as well as any treatment-relieving measures the patient has had in the past. The physical examination is directed toward the identification of predisposing factors contributing to the patient's instability.